Flying in the Wind

[Whirlydog]

There is a discussion under "Bad day of Flying" dealing with flying in the Wind. I believe this is a safety concern that needs to be understood. Thus this poll. My hope is that it can get us started in the right direction in understanding.

[Phil_Ruffin]

Fantastic idea Shawn....

[Udi]

oh brother!

I have turned into up-drafts and into down-drafts. I have gained and lost altitude due to poor altitude and airspeed control.

You may want to make the question more specific if you want this poll to have any value.

Udi-

[Whirlydog]

I can't change the question but maybe Todd can when he has a chance.

Todd, Please change the poll to read as follows:
To all pilots: When flying in windy conditions have you eperienced any real gain or loss of altitude when turning in a sustained wind? Please ignore those times cuased by gusts, up/downdrafts, and when you have changed your power settings.

Also remove the yes and leave the rest for answers.

I hope that is specific enough.

Thanks Shawn

[Chuck_Ellsworth]

Shawn:

For this poll to have any real meaning you should maybe ask the question based on more substancial evidence than "felt"

I know that you are trying to arrive at some understanding about how things fly.

However using what you "felt" was happening can be very, very missleading and the exact oppisite of what has or is actually happening.

A better example of what a flying machine is doing and what you "feel" is happening would to just go flying with someone and blindfold yourself...

Then try flying by feel.

When after a few seconds that goes all to hell and the other pilot gets the thing back under control have him / her fly with you blindfolded then you tell him / her what the airplane is doing.

That will answer the "Feel" reliability for what is really going on.

But hey, good to see you are at least looking for answers.

Chuck E.

[StanFoster]

Shawn: This poll will give false results. Your perception of what is going on is biased by the large differences in observed ground speed. What you "think" is happening is biased by what you are observing. Its no different than if you are flying downwind and close to the ground...you think your machine is really performing....then you travel at the same airspeed going upwind and you now feel like you are pulling a wagon of beans. Your machine is performing exactly the same.

It does not matter which direction you turn while traveling in a sea of moving air. You will have exactly the same altitude changes with the same stick inputs.

Just ask yourself this.....if you are flying in a steady wind and you enter into a shallow descending spiral....your rate of altitude loss will remain constant as your spiral enters into the upwind portion...and this rate of descent will remain constant as you then go trough the downwind portion of your spiral.

[Whirlydog]

I can't change the question in the poll. I don't have the edit capabilities

I agree with you that "feel" is the wrong term and that we need real data and experiences.

After Udi said that my question was not specific enough, I tried rephrasing the question and asked Todd if he could change it. Todd either has not had the time or is unable to change it. What ever the case it does not matter now. I will just repost a new poll if we agree that my new question is specific enough. If you don't like it, tell me how would you phrase it.

The New poll would read as follows:

TO ALL PILOTS: While fling in windy conditions have you experienced any REAL gain or loss of altidude and or airspeed when making turns in a sustained wind? PLEASE IGNORE CONDITIONS CUASED BY UP/DOWNDRAFTS, OR CHANGING OF POWER SETTINGS.

Shawn

[Chuck_Ellsworth]

Shawn:

Your question has at least given us some understanding of the lack of understanding by some thus far by their answers.

I wonder if that lack of understanding of simple physics and aerodynamics has any connection to the high rate of accidents with Gyros?

Chuck

[Whirlydog]

Chuck,

I will agree with you 100% that lack of understanding about the physics and aerodynamics of flight has contibuted to a lot of accidents.

Just as in Math, 2+2 is easy to understand, bit it gets harder the more we advance. When we progress to calculus and start talking about integrals. derivitives, imaginary numbers etc it can become quite complex. the same is true with the physics and aerodynamics of flight.

I highly reqard and respect your opinion, You have over 40yr of experience (I think I read that somewhere) flying and teaching people how to fly. Thus your opinion carries a lot of wieght.

Just becuase something that has been taught for the last 40-5-100yrs does not mean that a complex piece of physics or aerodynamics hasn't been overlooked in regards to gyroplane flight. There has been a lot of study dealing with fixed wing , rocket, and helicopter technolgy but very little toward that of gyroplanes. When rotary technology shifted toward helicopters, gyroplanes fell by the wayside and almost became a footnote in aviation history.

That is why I keep dogging this issue, so that we can understand what is happening and hopefully save a few live down the road.

We are the new test pilots that are taking over what was drop for closed to 50yrs. I am sure we will find a few nuances that apply only to gyroplane and no other form of flight. All I ask is that we keep an open mind and help each other discover and understand what those nuances may be.

shawn

[GyroRon]

Chuck, the only fun we will get out of all of this is when Shawn and some of the others finally get in a gyro and try to prove us wrong and see we were right. Then have to come here and read all of this in these threads where it was explained very well and in a way anyone should be able to understand, that any drop or increase in altitude is only due to the pilot not maintaining airspeed because he or she let their eyes following the ground fool them into flying slower when turning downwind.

Where is Craig Wall and Chuck Beaty when you need them?

[Chuck_Ellsworth]

Yeh Ron:

How true.

I sure miss Craig, the guy really had a good message.

Chuck B. is still lurking on Norms forum, I don't get on there much because I can't access it from this computer and have to connect my lap top.

What really frustrates me is this constant reinvention of the wheel.

Now if one of these guys wanted to discuss wind shear and dutch Roll in swept wing Jets up high enough to be operating in the coffin corner, that at least would be interesting.

But for Gods sake please accept the possibility that those of us who have flown a life time in most every conceivable contraption known to man and outer space aliens have figured out the basics....

That is all I want.

By the way, why aren't we fighting. ;D ;D

Chuck E

[gyromike]

Where is Craig Wall and Chuck Beaty when you need them?


Most likely lurking, and shaking their heads in amazement.

[GyroRon]

Chuck I don't WANT to be fightin with anyone. I am glad were getting along. ;)

[Chuck_Ellsworth]

Neither do I. ;D

[StanFoster]

Shawn: I just read on another forum about flying around a hot air balloon. It jogged my memory of doing just that last summer.

My friend was in his hot air balloon early one evening and the winds were at 15 mph which was his maximum. I was taking pictures of his balloon as I circled around him in my gyrocopter. I was able to just set up a constant turn and I didnt have to correct for any wind..because there was none. It was the simplest turn around a point I had ever tried. What I was actually doing was a turn around a moving point which was of course traveling along with the wind

Now...had I referenced to a tree on the ground and tried to make a turn around a fixed point...just as all pilots do in training....then I would have to ever increase my back stick as I went down wind and then gradually eased off the backstick as I went upwind.

Just this example of flying around a hot air balloon is concrete proof to me that it DOES NOT matter one bit which way you turn in a wind. But in reality..anyone that has the basic aerodynamics down already knows this.

[Chuck_Ellsworth]

Stan :

;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

[StanFoster]

Chuck: Ten smileys....THANKS ;D

[Heron]

Now . . .now . . .getting tears in my eyes here . . .isn't love beautiful?
Back to where it started: it seems to me some guys are talking about the moments after take off and turning downwind in a situation less than optimal. (power curve, lack of speed and all the good stuff)
As you are flying and with the proper inputs one pilot can turn anywhere he cares without any loss of altitude.True?
Lets add to it, shall we?
Fiction: a gyro flying straight and level, power setting locked and God turn the Big Fan off, reaction? Now God put the Big Fan blowing on the rear of the gyro, reaction?
Case # 1 what the inputs to keep it s/l
CAse # 2 the same
Thansk
Heron

[Whirlydog]

Hi guys, I have been gone all weekend, and the next few weeks are realy busy so I am not going to be able to continue much in this debate.

Ron, you said the most fun you will get out of this is when I start flying and try to prove you guys wrong. I hope that when that days happens, that you guys are right, but if not, I also want to be prepared.

since I live in an area where the wind blows more often than not I will use extremely caution when learning to fly in windy condition. Since it will be my safety and my life on the line I will prove to my self what is fact and what is fiction.

I agree with you guys 100%!!!!! that if you MAINTAIN AIRSPEEED your altitude will not change. I also realize that airspeed and ground speed will not be the same, and that my actual GPS readings will be a vector determained by my airspeed, windspeed and direction. Just let me say THESE WERE NEVER PART OF MY ARGUEMENT, AND I TOTALY UNDERSTAND THAT PART OF THE DISCUSSION.

My questions and arguement revolved around how can turning in the wind not effect my airspeed. MY common sence tells me it can. You say that it does not. We will leave it like that until I can go out and fly and discover the truth for myself.

Ron, I would like to congradulate you with coming up with the most thought out and reasonable explanation as to why people may be loosing altitude on downind turns, and I am sure this does happen. I am just not sure that is the only answer.

Gentle have a nice day and know that I have enjoyed this debate

Shawn 8)

[Chuck_Ellsworth]

Shawn :

You said. Quote:

" Since it will be my safety and life on the line I will prove to myself what is fact and what is fiction. "

I do not know what age you are, but I cannot believe that anyone would continue to deny basic aerodynamics and physics when hundreds of thousands of people have learned to fly and accept and believe these facts.

Am I to believe that you will enter flight training with the attitude that you will not believe your flight instructor, but will stubbornly insist on proving simple basic facts to yourself?

And the answers to your question shows that ignorance is rampant among some within this group.

Of course I once again have made some statements that will probably result in a few getting all agitated at me.

But so be it.

Chuck E.

[GyroRon]

Shawn, all your GPS readings are going to show you is how fast your GROUND speed is Period. Sure flying in the same direction as the wind is blowing across the ground the GPS reading will show a higher ground speed and flying into the same wind it will show slower ground speed, but that is all it will show you.

Your airspeed indicator will show you how fast your flying through the air and that is what counts for maintaining altitude and so on.

If you fly with your eyes on the GPS readings it is the same as flying with your eyes fixed on points on the ground and it is the same thing I have said all along, if you use ground speed to fly by you will slow the gyros AIRSPEED as you turn downwind and then can get behind the powercurve and if too low - like under 100 feet low in most cases - you can smack the ground.

But go prove it to yourself. Find a gyroplane CFI and ask him to show you downwind turns. If he can't maintain altitude in a normal downwind turn, then RUN away from him, as he shouldn't be flying, much less teaching.

[Whirlydog]

Ron, as I said above I know what the GPS and AIRSPEED indicators are telling me. I am not confused about their functions.

Chuck, When I do start flying instructions I am not going to dispute everything the flight instructor has to teach me. He will have a thousand things to teach me and just becuase I do not understand and may need to experience this ONE THING in order to believe, does not mean that I will question every thing he has to teach me. I Believe I am teachable, and not so old that this old (47)dog can't learn new tricks.

I have understood most everything you guys have tried to teach me here. What I don't understand is the WHY! To be told that something just doesn't happen a thousand time doesn't explain WHY it doesn't. Ron and Al are the only ones IMHO that have tried to explain the WHY behind WHAT happens and not just WHAT happens.

Chuck, Udi and others, you have tried valiently, but I just don't see the WHY coming through. I do value the Time, Patience, and Efforts you all have shown trying to teach some of us dim witted or obstanant people such as my self, in all things related to flying just not this issue. Keep up the good work and may we all continue to learn.


Shawn

[ToddP]

I've changed the poll to read as Shawn asked me to change it. I've also reset the poll since it reads differently now. Sorry for the delay getting this done.

Todd

[Chuck_Ellsworth]

Shawn :

When I post advice here I do it for free.

When I teach students I charge for it and ensure that they understand " everything " about the subject. ( For ground school my daily rate is $500. 00 for one or more students. )

This is a free " talk " forum and as such there is much to be learned here.

I am sure you will learn to fly Gyros because they are arguably the easiest flying machine to learn to fly.

However I am still mystified at the gyro community and the reluctance to go to a flight school and avail themselves of a structured ground school.

If you did there would be far less mystery about the basics of flying.

Chuck E.

[Whirlydog]

Thanks Todd I appreciate it.

Thanks Chuck for all the free adivice you are willing to share.

Shawn

[Heron]

Today it was very windy in Pompano and I had the opportunity to observe the heli pilots training all day (the shop is cross street in the back of the Pompano Air Park)
It seemed to me that the task was: steep climb, stop, roll to the left an 180 back to the runway, holding altitude.
I've seen many atempts go down and the student go back till they got it right.
And then there was the seagulls and buzzards . . .
What a show! Seen them fall out of the sky and gain speed to go back up and do it again . . .just for the pleasure of flying!
Some pretty nasty gusts and the big birds turn every way possible to keep it going . . .
They turn down wind and like a bullet they come down in a pendular like motion. Also they have this way of folding back the wings to descent rapidly and gain speed to keep going headwind without flapping the wings.
Just a lesson in wind turns . . . .
Heron

[Whirlydog]

It has been said that you can't change physics and that math doesn't lie, so I have come up with a problem for you guys to solve. Call it a brain teaser if you like.

A guy is sitting on the runway waiting for clrearence to take off. He is told he will be taking off in a 20MPH headwind coming out of the North. He verifies this it by looking at his airspeed indicator and it is reading 20MPH.

Now this AC has a GPS that determains ground speed and AIRSPEED indicator and an new gadget that show the thrust output of the engine and prop and is also computer controled to maintain what ever you set for the output. The new Thrust indicator /controler has been calibrated so that 1 TU (thrust unit) is required to gain and maintain 1MPH of airspeed. IE>On a calm day no wind, to fly at an airspeeed of 50 Mph, the thrust controler will be set at 50TUs and the indicator will show 50 TUs.

This guy Knows that to get his AC airborn requires an airspeed of 30 MPH. He decides that he want to fly at an airspeed of 50 MPH.

1. What does he have to dial into the THRUST CONTOLER (TC) to be able to lift off the runway and fly due North at an airspeed of 50MPH? (remember he is already reading an airspeed of 20MPH)

2. He climbs to a 1000 feet levels off, he is flying at an AIRSPEED OF 50 MPH, What is his TU and Gound speed?

3. After flying North for a while he decide to fly south and return to the airport. He does not change his Thrust settings, so the TU will remain constant HE then makes his turn and starts heading south. What is is current ground speed, airspeed?

Please show your figures and how you derived then.

Shawn

[GyroRon]

Shawn..... Your kidding me right? You still haven't grasped this? Go to the airport and do whatever it takes to get in a airplane or helicopter gyro or whatever and put this to rest. I will give your questions a shot in a few minutes.

[GyroRon]

Okay to answer your questions.....

First off it will require more thust to climb than to just fly straight and level, at a given airspeed. I do not know the math to come up with the amount of additional thrust needed so I will just take a guess okay?

So to question 1. He needs 30 mph to lift off and wants to climb out at 50. So he will need to set the TU setting to 50 to go 50mph. Since he is in a climb it will take additional thrust so the TU setting may be set for 60 or 65. NOTE: had he just wanted to lift off and fly the runway and never climb out, he could have lifted off and flew right at lift off speed with a TU setting of 30.

Question 2. I will assume he leveled out and kept flying north into the wind, you didn't say..... The TU setting is 50 and the ground speed is 30.


Question 3. His airspeed is still 50 and his ground speed will jump up to 70.


Now do I need to explain better how I came up with my answers? I will try to do it briefly

Question 1. You said the plane lifts offs at a airspeed of 30 mph. So using your TU example he needs 30 TU to go 30 mph. But you said he wants to fly at 50 so the TU will need to be set to 50. But he is wanting to climb as well as fly forward, so you have to add some additional TU for the climb. Hence I come up with 60-65 TU. THE AIRSPEED HAS NOTHING - ZERO - TO DO WITH ANYTHING IN THIS QUESTION.

Question 2. This is so simple Shawn it is retarded. You said the TU setting is equal to airspeed. So to fly at 50 mph then he needs a setting of 50 TU. EASY!!! then you ask what is his ground speed. EASY AGAIN!!!! Just take the speed of the wind across the ground - you said 20 mph - and subtract that from the airspeed - you said 50 mph - and you get the ground speed of 30 mph. NOTE: you never said in this question he was still flying straight into the wind but It was assumed in my answer he was flying right into the wind.

Question 3. You never said how fast he was going or what TU setting he had in question 3 but it is assumed he left it all the same as in question 2. SO..... He leaves the TU at 50 and as long as he maintains steady airspeed by not allowing any climb or sink in the turn, he will come out of the 180 degree turn still doing 50 mph airspeed with the TU setting of 50. His airspeed is still 50 mph since the TU is still set at 50 TU. His ground speed will be the airspeed PLUS the speed the wind is blowing across the ground since your flying WITH the wind now. So take 50 mph and add the 20 mph and your ground speed will be 70 mph.

PLEASE Shawn tell me you understand this by now, Gee Wiz! :o

[Chuck_Ellsworth]

We are doing no one any good by basterdizing the language of aerodynamics by inventing new words to explain a very basic concept.

There has been enough discussion here on this subject that if someone cannot grasp the physics involved then so be it.

Then again having read the answers to this poll, what do we do with the 66% who haven't got a clue about the subject?

Maybe this is just another reason why the general concensus about gyro pilots is the way it is.

[Udi]

Shawn,

I hope you are not offended, but I have a suggestion for you. Go to the following web site and learn it carefully. You can learn a lot from this site, but start with the section about flying in wind. This is an excellent source so spend as much time as you need to understand this subject completely.

http://www.av8n.com/how/htm/maneuver.html

Udi-

[Whirlydog]

Udi, Thanks, I look forward to reading the material you recomended over the weekend.

Ron, IF airspeed has nothing to do with the equation then you are correct in your findings, but I don't see how it can be eliminated since it is a force acting upon the AC.

Chuck, you have often said that this is simple physics and dont know why we can't understand it. I tried to present it as a simple physics problem of two seperate forces and thier effects on the operation of an an aircraft. If their is a flaw in my problem what is it? Can you give us an equation that proves your point? I think that by the law of forces, that my problem shows there can be an increase or decrease in airspeed and lift cuased by the wind.

Well I am off to go read the material Udi recomended.

Shawn

[Whirlydog]

OOPS

[StanFoster]

Shawn: You need to understand the concept that when you are flying..it doesnt matter what the air is doing with relation to the ground. All that matters is what you are doing with relation to the air.

Like I mentioned a long time ago,.,I flew around a hot air balloon last summer while it was traveling along the ground in a 15 mph wind. I had to make no adjustments as I was doing my turn around a moving point.

Udi had the best advice as a place for you to study.

[GyroRon]

Shawn I just am at a loss of words on how to explain in any clearer. The wind does not effect the aircraft like you expect it does.

Let me try this to maybe help explain it more... If you were to to fly into a 20 mph headwind at the 50 mph you mention in your post, I say the airspeed is 50 mph and the ground speed is 30. If you were to hold out the window a wind speed meter it would read 50 mph even though the wind speed is 20, because your moving Through the air at a speed of 50 mph. At the same time if you were to take a real super long stick with a bicycle wheel on it that had a ground speedometer on it, and hold that wheel on the ground you would see a reading of 30 mph Because your flying at 50 mph in air that is blowing 20 mph in the opposite direction the plane is going, giving you the ground speed of 30.

Do all the same stuff as above after you turn 180 degrees and head south with the wind and your still going to show 50 mph in windspeed on the handheld wind meter hanging out the window, But now your going Through the air at 50 mph while the whole mass of air is blowing across the ground at 20 so your bicycle wheel will show a speed of 70 mph.

Sorry if you still haven't seen the light! I just don't know how else to explain it. I think once you get some stick time in ANY kind of aircraft you wil grasp this whole thing down quite easily but it should make sence to you at this point either way.

Have you not flown before Shawn?

[Phil_Ruffin]

How's this????

sorry will try again to post graphic.

[Phil_Ruffin]

Now how's this?

[Phil_Ruffin]

And this?

[GyroRon]

Looks good to me Phil. Except the gyro CAN lose altitude without pulling the throttle back. Simply allowing the gyro to slow down to behind the powercurve by pulling back pressure on the stick can start a loss of altitude. This is the whole point of the subject..... If you allow ground references to influence you to adjust your airspeed, when turning downwind on a day like the one in our example above, the sudden rush or percieved increase in ground speed will cause a lot of folks to mistakingly pull the stick back to slow down and USUALLY pull power too. But just pulling aft stick pressure can cause a loss of altitude.

[Heron]

You guys are great, thanks a bunch!
Now the original discussion was about a sharp turn downind and loss of altitude related to the turn.
Mostly for those ground smacking maneuvers . . .
Turning around the baloon in an angle wide enough will allow for the pilot to keep altitude steady if air speed is kept (no throttle changes)
The whole situation boils down to executing a proper turn in order not to mess up, specially at low altitude, like take offs followed by turns.
The Russian video (dont like Crazy Ivan) shows a turn made with power enough to gain altitud instead of loosing it.
Any aircraft capable of doing 180's will loose altitude until it regains air speed enough to climb again.
It is a great discussion and very well maintained, thank you all!
Heron

[Chuck_Ellsworth]

Several things should be mentioned in this discussion.

First and most important before anyone starts a discussion regarding aircraft handling proceedures it is absoloutely necessary that those who are involved in the discussions be conversant with the subject, at least enough to take part in said discussion.

What we have here is a situation wherein several people have gotten off on a discussion that started with the basic physics of fluid dynamics, and then turned into a complete screw up by the mixing of fluid dynamics with the aerodynamics of a gyroplane in the turn.

You cannot change your flight path from straight and level to turning and maintain airseed and altitude without changing several other factors the wind over the ground is irrevelant when considering the forces acting on a gyroplane when it is rolled into the banked attitude to start a turn.

The lift factor will increase in direct proportion to the angle of bank if the same altitude is to be maintained, this in turn produces drag which will either have to be overcome by adding power or increasing the pitch attitude.

If you increase power and pitch attitude you can maintain the same airspeed and altitude.

If you do not increase power you will lose either airspeed as you maintain altitude or you will lose altitude.

O N C E A G A I N ! !!

The damned wind direction has zero effect on a flying object in relation to its flight path through the air.....

N O W....

May I make another comment.

Where are all the North American Gyroplane Flight Instructors during these discussions?

Then maybe it would be better if some of the North American CFI's do not comment especially the RAF Factory approved CFI's who obviously do not understand the subject anyhow, and should not hold the CFI certificate in my opinion.

Once again before you get all wound up in arguing about this subject, please at least research the basics.

Or even better yet just tell me to go pound salt and save me all this typing. ;D

Chuck E.

[Phil_Ruffin]

Ron, your right if you use back stick pressure as you said you will loose air speed and altitude. I probably should have typed it in on the expamples somewhere, also about the ground reference issue. These very rough quick drawings were to try to help you explain to Shawn in your previous post. When I get time I will modify the graphics to reflect your comments.

Heron, you are also correct. The orig. discussion was about lost altitude in a sharp down wind turn, but somewhere the subject got changed to a high altitude turn in a moving air mass. Then the post got confusing because no one knew what the other was talking about.

When I posted my comments before on down wind turns it was expressed that I didn't understand. I do understrand. Maybe my earlier comments weren't clear enough, I'm an artist not a novelist.

I am also going to draw an example of the sharp down wind turn at low altitude. It is my belief that you don't have to be at low altitude to loose altitude when making this type of turn if you are flying from point A to point B without some kind of control input.

Later, Phil

[PW_Plack]

Chuck,

It occurs to me to point out that I don't believe any of these guys is challenging the accuracy of what you say. They just want to understand it, even if they can accept it (or prove it to themselves in flight) before the understanding comes.

I've asked a few stupid questions in the last two years as I tried to ramp up from zero to PPL. I've also asked a question or two that ended up pointing out a couple of cases of experts with misconceptions.

You coming for that free lunch at Scappoose January 10th? I got elected Vice President of Chapter 73 after running on a platform of getting more cranky old geezers to show up. Don't let me down!

By the way, an invitation to all...NAFI Master Flight Instructor Dave Wiley is providing a free gyroplane ground school before the next three Chapter 73 meetings. Two-hour sessions, 10a-12n Jan 10, Feb 14, Mar 13, six hours total. The only cost is getting there, and a voluntary donation will be accepted to help cover photocopy and other costs. I believe you'll need the FAA's Rotorcraft Handbook as a class material. Pot-luck lunch follows at noon, chapter meeting at 1pm.

Scappoose Airport is along the Columbia River north of Portland, Oregon. Airport identifuer is KSPB. The classes and meetings will be held at the Northwest Antique Aircraft Club, kitty-corner across the field from Sport Copter.

[Whirlydog]

Hi guys, I think I have an answer to all our questions concerning this thread.

By the time I finish this reply I think I will be able to prove that what you have been saying is 100% correct, except in a certain circumstance . I also hope to explain in what circumstance the wind will have an effect and maybe explain what happened in the examples where people did turn down wind, lost atitude and crashed, some loosing their lives. THIS WILL BE A VERY LONG POST, SO PLEASE BEAR WITH ME AND READ ALL THAT I HAVE TO SAY BEFORE YOU PASS JUDGEMENT AND REPLY.

Friday night I read the material Udi recomended and also dug up some old physics books to insure there was nothing wrong with my problem as presented. There is one force we( at least me anyway) have been neglecting in this discussion. I kept asking myself what am I missing that I can't except these answers. I can see where the wind has an effect on things every day, but I could not see how the wind would effect an aircraft in one way (drifting off coarse, groundspeed vs airspeed etc) and at the same time not effect my lift ratio. I thought how can you say in one breath that wind will do this and yet in the next breath say the wind has no effect, how could it blow me off coarse but not add or decrase lift?. When I realized which force I was negecting everything fell into place. That force is GRAVITY. Once you have gained enough lift to negate gravity then you have just became a weightless object floating in the wind (pitcure a piece of paper blowing in the wind). With that said evrything you have been saying is 100% true except in the circumstance I am about to discribe. Which maybe be another explaination as to why some pilots have lost altitude and crashed doing a down wind turn.

Now let us go back to the problem I presented earlier and progress from there. Basicly here was the set up. I have an AC that has a GPS,and AIRPSEED gauges and also a Thurst indicator /controler that you have to dial in a particular TU (thrust Unit) and the engine and Prop will start producing that amount of thrust and the TU indicator shows you the current amount of thrust you are achieving. The TU controler is calibrated so that 1 TU will produce an increase of 1 MPH in airspeed. I had also stated that this AC required a minimum airspeed of 30MPH in order to lift off the runway, and that he was headed and would be flying in a head wind of 20Mph. I then proceeded to ask what power setting he would need to fly at an air speed of 50MPH. I also asked what his ground speed would be ect. With that said let go see what happens when we apply gavity to this problem.

Let us also say this AC is a a gyro and does not have a prerotor. Our pilot is sitting on the runway waiting for clearance to takeoff. He is also headed into a 20MPH headwind. He has handstarted the rotor and since he is headed into a headwind this wind will also help to encrease the speed of his rotor. He checks his airspeed and it reads 20MPH. Becuase he is headed into a head wind the rotor is now turning at the same speed he would have going 20MPH down the runway on a calm day. He gets his clearance to take off and he starts down the run way. Let us at this point say he add 1TU at a time and see what happens and when it happens. Between 1-10 TUs he only adds forward speed and nothing happens. At 10 TUs , his airspeed says 30mph and his gyro is going to TRY to lift off. This is what happens. For one microsecond the gyro does lift off, and it is now one with the air. His altitude is now let say the thickness of a peice of paper, he begins to flybackwards, the airspeed goes from 30 to 10MPH and he looses lift. Since this gyro need an airspeed of 30 MPH to generate enough lift to negate gravity, it does not have enough speed or lift so gavity pulls it back down. Thus Gravity will continue to keep the gyro glued to the ground, until he reaches 30TUs.

What happens when he reaches 30 TUs ? When he reaches 30TUs he has reached enough speed to maintain airspeed of 30MPH and he is now officialy airborn. he is flying with an airspeed of 30MPh a groundspeed of 10MPH.

I am told that I have to get off the computer so that my visiting mother-in-law can go to bed. I will finish this either tomorrow or monday when I get a chance.

Can I ask one large favor of you guys???? Will you please refrain from any comments or replys on this thread until I have finished what I have to say here. Even if it is to say "think you got it know " or what ever. If you feel you must respond please put it under the other thread. I will find it and read it. I would like my whole theory spread out in one area without a conversation break.

Thanks Shawn :o :o Iv'e seen the light

[StanFoster]

Shawn: I have to break your request not to post till you write some more....but I have to.

You have a serious error in your thinking on your airspeed going from 30 mph to 10 mph at the moment of liftoff. You will still have an airspeed of 30 and will not be flying backwards.

You are confusing your airspeed at the moment of liftoff..and then referring back to your ground speed of 10 mph.

[airRanger]

ANOTHER THOUGHT ::)

How much "ground speed" would be needed to take off "down wind" to overcome a relative windspeed of 30 mph? (hope I worded that right)
dennis

[gyromike]

C'mon guys!

This ain't rocket science. Every licensed pilot on the planet learned this in the first 5 hours of training!

Shawn, it would take 30 of your mystical TU's to get up to 30 mph IAS (Indicated Air Speed). It doesn't matter whether you're pointed into the wind or away from the wind. In your example, it would take 20 TU's just to sit still in the wind without rolling backwards. Another 10 to reach 30 mph IAS and flying speed. Nothing changes when the gyro breaks ground, or touches back down again.

Dennis,

Using Shawn's example gyro, at 30 mph IAS a takeoff into a 20 mph headwind would give you a groundspeed of 10 mph. A downwind takeoff would give you a groundspeed of 50 mph.

[StanFoster]

Shawn: Ron's posts on desribing what goes on in a downwind turn exactly desribe what most of us here already know. He was kind and patient enough to go into extra detail with you on this matter.

In a nutshell.....while flying in a sea of moving air...it makes no difference what so ever which way you turn. If you do the same stick and throttle manuevers..you will get the exact same results. Its when you are near the ground your perception of your true airspeed is being biased by what your eyes are telling you by the changing ground speed. A newbie has to be extra careful here not to let these perceptions of changing groundspeed result in changing their airspeed. If you start letting your groundspeed influence you to change your airspeed...then of course there will be a difference turning upwind compared to turning downwind.

I would never fly solo until I had this BASIC aerodynamic principle cleared up. This confusion on this topic is a major contributor to aircraft accidents resulting in many deaths.

[PW_Plack]

Shawn,

We need to stop your long post when you make your first incorrect assertion. Please explain what mysterious force of nature causes the gyro taking off to instantly lose 20 MPH of airspeed just because the wheels leave the ground, and we'll hang in with you.

[GyroRon]

Thanks guys for beating me to it! ;D

[Whirlydog]

Hi guys, I am back

After I wrote the first part of my disertation, and went to bed I realized that in actuality It may take 20 of my TU to even get the AC even moving down the runway. So Mike you are correct. :) But I wrote that with the theory that if 1TU could move me on the ground at 1mph then we would have 10MPh at 10TUs we would have what I will call a studder movement keeping me moving at 10mph ground speed until I reached 30Tus. A snapshout of what might be happening. Lets just say I was wrong and we can continue from there.

I think we can all agree that we would have to reach a ground speed of 10MPH and an airspeed of 30MPH to gain enough lift to become and remain airborne even if it is less than an inch off the ground. That our AC is comparable to a piece of paper floating in the wind. AND YES I would have to add more power if I want to lift any higher.

Shawn

PS I take it every thing else is correct , If not then what else am I missing before I continue.

[Whirlydog]

Okay let me see if we can come to an agreement on the next issue before I proceed any further. As long as I am tied to the ground the wind can have an effect on the gyro. Lets say we have two gyros tried down on the tarmac one is facing upwind and the other facing dowwind. If the the rotors are free to turn will the wind cuase the rotor to turn in opposite directions?

I believe this would be the case. I have a small windmill and if I go out in the wind, turn the thing 180 degrees I can watch the blades slow down and reverse direction. I am just trying to establish that this same thing can happen on a gyro.

A thought came into my brain ealier and I would also want to know if the following would be theoricaly possible, maybe not feasable but at least possible. Where I live the wind especially in the spring can be blowing a constant 40+ MPH. If I had a gyroglider could I have it tethered and fly it like a kite. Just think I could be flying and it wouldn't cost me a dime. A life size gyro kite ::) hummm I kinda like this idea what do you think

Shawn :D

[rehler]

Shawn,

Not a new idea but a good one. It is popular on coast lines where the wind is constantly coming off the water. Many people have tied gyro gliders to a rope like you suggest. It seemed to work fine.

[StanFoster]

Shawn: I have taken off several times in high winds by just adding power and more back stick till the gyro just lifts off without moving forward. It will just kind of bob around while you stay in ground effect.

So lets for examples sake say you were staying over the numbers at one foot altitude in a 30 mph wind. Mind you this is definately flying behind the power curve.....but you would be flying through the air at 30 mph..with your wheels off the ground but not moving over the ground. You could then turn down wind and still remain just one foot off the ground. However,,,you are keenly aware of your altitude and you have this awesome feeling that you are really moving as the ground is moving under you at 60 mph. But you are still flying only 30 mph through the air and still behind the power curve. If you let the ground speed influence your seat of the pants...you will slow up your airspeed and you are in trouble. Your turns are obviously made at more altitude and this is another part to the problem. As you make this downwind turn...the error to slow up your airspeed because of the very high groundspeed causes you to settle and since you have some altitude..you may not notice this until too late. So here you are settling..your airspeed is decayed and you still think you are flying plenty fast because of the ground speed under you.

After you have lots of experience...flying at ten foot altitude on a windy day and doing 360 degree turns will make it very clear that you have to tune out the ground speed and maintain your airspeed.

[airRanger]

Mike Gaspard said......
Dennis,

Using Shawn's example gyro, at 30 mph IAS a takeoff into a 20 mph headwind would give you a groundspeed of 10 mph. A downwind takeoff would give you a groundspeed of 50 mph.

Mike , my point was, you still have to overtake the tailwind. to be able to take off.
If there's a 30 mph tail wind and your rolling at 30 mph (your still on ground) as soon as you "leave" the ground (if your able, because you dont have any relative wind) are you saying then, that you'll automaticly be doing 60 mph?
Im just trying to get a grasp on this, NOT argue.
Dennis

[Whirlydog]

Air ranger,

what they are saying and I agree with is that in your question/example if you are rolling at 30MPH with a 30mph tailwind your airspeed would be 0 MPH. you would have to be rolling at 60 mph to get an airspeed of 30MPH to start flying if you are using my example of an AC needing 30 MPH to lift off the ground.

I understand what these guys are saying, but I have been trying to see, is if there is anyway that someone might loose airspeed and altitude with out reducing power when making a turn down wind. With me it has been a thing of eliminating all conseavable ideas and see what left. I have even tried my best to trip these guys up. These guys haven't budged. My respect for these guys grow every day. We have some great people on this forum.

MY knowlege is very limited and at first I didn't understand either. I do now. I still have one more theory to try out on these guys . I keep working this theory out in my head to see if there is a flaw in my logic, and/or how to explain my remaining thoughts on this subject in such a way, that it may be considered as an possibility even if it is highly improbable.

I will mull my current idea over the holidays before I spring my next questionable idea. In the mean time I do have a couple of questions?

1. When you make a turn will you loose any rotor RPMs?

2. What is the correct proceedure for engine out landings?

Yes I have read a few peoples experiences with engine out, and the proceedures, I would just like to have it explained again here. becuase the answers to these two questions will help me to either eliminate or help explain my remaining thoughts regarding this issue of flying in the wind. Also the Info would be here close at hand for everybody with out having to do a search. that is if my last idea has any merit.

I REALLY WANT TO THANK EVERYBODY FOR YOUR PATIENCE AND WILLINGNESS TO KEEP AT IT. I hope true understanding will come out of it for everyone who has questions but are afraid to ask, not just me. Maybe for a shortime I should change my handle to Bulldog instead of Whirlydog. ::)

YOU ALL HAVE A VERY VERY MERRY CHRISTMAS AND NEW YEAR.

Shawn :)

[gyromike]

Dennis,

Shawn beat me to it.

In your example with a 30 mph tailwind, you would need to acheive 30mph groundspeed just to catch up to the wind, with you Air Speed Indicator showing 0mph.

You would then continue to accelerate to 30mph Indicated Air Speed to get airborne (assuming 30mph I.A.S. is the takeoff speed for our theoretical gyro).

At the point of liftoff, the ASI would be indicating 30mph, and a GPS would be indicating 60 mph over the ground.

You would eat up a lot of runway doing this.

The same gyro pointed into the wind would likely perform a vertical takeoff.

[StanFoster]

Shawn: If you make a turn and hold altitude....you will feel more than 1 g while turning. The more g's that the rotor gets fed, the more rpms.

While you are flying,...you should always be aware of the wind direction just in case your engine quits. It is better to land into the wind to keep your groundspeed slow. Get your airspeed to best glide speed....roughly 45...and be prepared for a steeper descent than normal. You should have already practiced dead stick landings over a runway to get the feel of it so that when the real emergency happens..there is more confidence at the controls.

Pick oout a good landing spot....and dont feel you HAVE to land into the wind. Sometimes your choice would be better to land parallel to a hedgerow with a sidewind than flying into the hedgerow;..if you get what I mean. Its all a judgement call....you try to pick the lesser of the evils of the options presented to you.

[birdy]

Have been reading this thread with interest,and agree with most of what has been said.I think Shawn has got the message.

However,as I tend to do, I'll throw a stick in everyones spokes.

Common knowlage states that your ground speed is irelivant to a coordinated down wind turn,true .....to an extent.

Ground speed is relivent.
I'll try to paint a picture,
You are flying at 50k,100' above the ground,into a 50k headwind.
In relation to the ground,you are staitionary. You,your machine and the blades have no stored movement energy.[the blades energy is enclosed in the "disc" they fly in,but have no "movement", in relation to the ground.]
The engine only has to produce enough energy to counter the effects of gravity and drag.
To turn down wind,the craft has to gain "movement"energy, because it is changing from a 0 ground speed situ. to an eventual 100k ground speed situ.[with the tail wind.]
This "movement" energy can be gained from two sources.Either gravitational energy,[sacrificeing altitude] or by producing it with your engine.The gravitional energy would not be a good option because we don't have much to spare[starting from 100'].So we opt for the engine.
The engine now has to produce enough energy to counter gravity,drag AND provide movement, IN RELATION TO THE GROUND.
Once we level out to the 50k ASI downwind, and are still at a steady 100', the engine again needs only produce enough energy to counter the gravity and drag. BUT , the machine has gained 100k's worth of MOVEMENT energy, in relation to the ground.
To turn back up wind,[if the conditions were perfect],would require 0 energy increase,so long as we finished up at 50k ASI,100' , 0 ground speed.
The motion energy we had gained by turning downwind ,and was stored in the craft cruising at 100k groundspeed was just used up to counter the centrifical forces during the turn back upwind.[we now have no motion energy again, in relation to the GROUND.

This is why we need to add energy when turning downwind, and don't need to turning upwind,to maintain altitude and airspeed.

Our ground speed is only an indicator of the available motion energy.

So, to an extent,the ground speed is relivent,only it shouldn't be confused with the airspeed as you all agree.

Hope all that dribble is understandable.

[Aussie_Paul]

Good post Birdy. A lot of people I am sure will be interested in what comes out of your comments. I know I will.

I have been in a number of little bun fights on this topic over the years, including if it is rougher flying into a gusty wind or flying with it!!!!!

I have never been able to get my head around what I call the "Inertia thing". I think this is what you refer to as "movement.

Aussie Paul.

[birdy]

Yeh Paul,inertia is what I'm refering to,only I'm assuming there is some other thick basterds like me reading this so I tryed to keep the language simple. [lets hope I'm the only one ay.]

[birdy]

As far as flying up or down wind gose,from a low level perspective,the "bumps" ,I don't reckon are any stronger or severe, but there tends to be more down,flying down wind and up flying up wind.[to do with the degree of change in AOA on the disc when you hit the verticle winds from opposit directions.]This would give the impression of needing more power to fly downwind than upwind at the same airspeed.
I put this effect down to the "rolling" of the air that's in closer contact with the surface.Country that "snags" more air[tall , spaced trees ] is always rougher on windy days than open country with the same windspeed.

Anything above 300' I know nothing about.

[Chuck_Ellsworth]

I ocassionally surf these subjects just to stay in touch.

Today I am finally convinced that after over fifty years of flying most every flying machine on the planet I have missed the hidden danger when turning down wind.

After careful consideration of the subject I think I have found where my problem came from.

My career started flying low level in the crop dusting business both fixed wing and helicopter.....and therein lies the problem, it was all done in no wind conditions and I was lulled into beleiving that all turns were equal having never been exposed to a down wind turn.

I then went on to fly heavy water bombers at low level for fifteen years and became exposed to all kinds of winds and turbulence.

Fortunately I survived in spite of not knowing of the danger of the down wind turn....I guess ignorance is bliss in my case.

However thanks to this group of deep thinkers I can now take measures to insure that I compensate for the dangers of turning down wind.....

How can I express my gratitude to those of you who brought me out from the darkness of ignorance on this subject?

Chuck E.

[Harry_S.]

Chuck;

How could you be flying for over 50 yrs? Your not even a year old yet, per your profile.

[KevinKing]

Ok, I'm not a pilot, so I don't really feel qualified to say this, but...

Why do you think your gyro (or any aircraft) must have momentum relative to the ground for it to be able to fly? What does the ground have to do with anything (other than influencing the wind near the surface)? What about the movement of the Earth? Why is there no difference between flying East or West? What about the movement of the solar system throughout the galaxy, or the movement of the galaxy throughout the universe?

My point is, the ONLY thing you need to worry about (except during takeoff or landing), is movement relative to the medium through which you are travelling.

[Aussie_Paul]

I agree totally Kevin, BUT I still do have a probem with the inertia of a mass. I would love one day to be happy with a how and why Scientific, not peoples opinions, explanation. nI would like to reduce my lack of understanding.

Aussie Paul.

[gyromike]

Paul,

It all depends on your frame of reference.

Have you ever moved around the cabin of an airliner at 600 mph?

Why didn't you shoot to the back of the cabin and splatter against the bulkhead when you stood up?

Were you able to walk forwards and backwards, or did you have to overcome the inertia of your body mass @ 600 mph?

Better yet, fly your gyro around in a coordinated 360º turn in high winds. Do you feel yourself pushed against the back of the seat on the downwind leg as you gained groundspeed?

Were you thrown forward against the shoulder harnesses as you turned on the upwind portion of the turn, as your groundspeed decreased?

Even better, do you hang from the harness as you fly around in circles...on the bottom of the planet? ;D

[GyroRon]

Holy Cow.... Scotty Beam me up, I can't believe this thread has been brought back from the dead. :o

[birdy]

Thanks Chuck E,For the inderect thanks,I think.
Kevin,mate, Read it again,you don't need momentum to fly[relative to the ground],so long as the conditions are right.ie;flying at 50k into a 50k headwind=no momentum.BUT, if you want to turn downwind,you HAVE to gain momentum,the momentum of 100k.[50k ASI+50k tailwind=100k GROUND SPEED.]Without this gain in momentum,you will simply drop from the sky through lack of airspeed.

This is what makes the relation between airspeed and ground speed very relivent WHILE TURNING DOWNWIND.

BTW Paul,those points are not my poinions,they are simple laws of physics,...........Opposet and eaqual reaction type stuff mate.

[GyroRon]

Hey Chuck.... I go coo coo for coco puffs ;D

[Chuck_Ellsworth]

Yeh Ron :

It simply amazes me that this subject would get so much discussion.

One would think that after almost 30 thousand hours of flying I would have noticed this down wind thing at least once.

But unfortunately I have never ever seen any change in the way an aircraft behaves regardless of which way you turn, up wind or down wind.

Speaking of physics Birdy.

If friction produces heat how fast could you hump a pail of water to a boil?

Chuck E.

[birdy]

Chuck E,thankyou,

I now know I can never take you seriosly,somehow I knew this would be your responce.Afterall,you are an EXPERT.

Instead of making inteligent,corrective comments you only do your best to belittle anyone who may have an opposing view.
Most people with your experiance and supposed concern for "newbes" would try to explain why I'm so far off the mark,or are you a typical exert and compleatly miss the point.

Am looking forward to greg explaining where Im going wrong.

[birdy]

Steven,are you trying to tell me chuck dosn't like me??? :(

Am not up with your lingo. :-

[birdy]

Steven,thanks for conferming the perseption of sarcasm,but don't think I'm worryed about him not liking me,I reckon I'd prefer it that way. >:(

I'v a lot of respect for Paul too,now that he listens more,alot of people here reckon he was arrogant,but I reckon now he is much more receptive.I'll have no problem having an INTELIGENT conversation with him,even if we are full o rum. ;)

Chuck is a crimminal waste of experiance,if he can't say something to do his experiance justice,he ought to say zip.At least then he'd have respect.

I'v never blindly accepted anyones word,espesialy people I don't know.

It's always interesting to talk to experianced people,but I tend to ignor the arrogant ones. :)

[PTKay]

Birdy,

I am having my aerodynamics class today afternoon and I will put this inertia question to my PhD teacher. We will see what he says.....

I find this question really interesting and have myself no ready anwser.

Don't bother irony and emotions, what counts is serious anwsers, I will try to get one for you.

PTKay

[PTKay]

BTW, Birdy,

with you moving to the US forum, it seems the Oz one is almost dead....,
no post since HOURS :(

PTKay

[Chuck_Ellsworth]

Birdy:

The friction thing was an attempt at humour.

You may think me arrogant, ignorant, sarcastic or any other description you choose...but there has to be a reason for my apparent tactics.

I use this method to try and jolt people into doing some research on the subject of aerodymamics and how aircraft fly.

The down wind turn argument is one of the stupidest subjects to ever be discussed in this or any other group.

It is as simple as 2+2=4.

It matters not to the aircraft which way you turn once flying in the air mass....period ....period...f...in period.

By the way your CASA seems to think that I understand the subject of flying. I'm a Canadian that holds CASA approval to issue type ratings to Australian pilots on Australian Transport Catagory airplanes.

So if some of you guys don't like my attitude so be it. I don't charge you for my time.

Chuck E.

[KevinKing]

Kevin,mate, Read it again,you don't need momentum to fly[relative to the ground],so long as the conditions are right.ie;flying at 50k into a 50k headwind=no momentum.BUT, if you want to turn downwind,you HAVE to gain momentum,the momentum of 100k.[50k ASI+50k tailwind=100k GROUND SPEED.]Without this gain in momentum,you will simply drop from the sky through lack of airspeed.


You're still talking about groundspeed. When you're flying 50 kts in a headwind, a tailwind, a crosswind, or whatever, your momentum/inertia is the same. You are flying at 50 kts relative to the surrounding air. The ground has nothing to do with it. If momentum were not relative, we'd all be flung to the back of airliners if we got up, and our cars would be flung off the planet if we decided to drive West instead of East.

I think what you're thinking about, is when you do those quick 180 degree turns (I'd love to see that!), you most loose your momentum RELATIVE TO THE AIR, and gain it back in the opposite direction. Ok, don't blast me too hard, as I said I'm not a pilot, and I'm only going on my knowledge of physics.

[quadrirotor]

Thanks Al Hammer.

[quadrirotor]

Thanks again Al Hammer.

[Aussie_Paul]

Ron, without the availability from Norms forum of all that archived stuff through the search facility, newbies to the forum have to ask rather than search.

Steve, I know the principles and agree with them.

If that jet liner suddenly reversed direction would I be rushed towards the back?

The reason that I ask is that a gyro can probably be reversed in direction quicker than any other aircraft. It may or may not be balanced during that severe turn.

Would this scenario change anything that we believe is normal?

Aussie Paul, just stiring up some deeper thinking outside the [_]

Gee that square took some doing when I am standing on my head!!!! LOL

[Chuck_Ellsworth]

I won't be around for long as we are about to start two more contracts, today I received conformation that we have the contract to get a PBY in London England airworthy and ferry it to Tel Aviv Israel.

Then it looks like we take one from Paris France to Sao Paulo Brazil to start a one year TV filming project of all of Brazil.

But as long as I'm around I may ocassionaly give my poliically incorrect slant on things.

What a lot of people here do not understand is the simple fact that I'm not a touchy feely socially correct kind of guy, naw fu.. that I just believe in telling it like it is .......from my way of looking at it.

Hey, how long do you think me and my crew would live in some of the worlds sh.t holes that we fly in if I were soft and caring about B.S. like being PC?

Chuck E.

[rehler]

Paul,

I think you have a good example. The aircraft is affected by the air around it. The person inside it is not affected by the air around the aircraft. If the turn around was quick - as quick as a gyro can turn - the person would feel the pull in the direction of flight.

The word "momentum" does have merit. It relates more to the gravity and mass of the pilot and gyro than to the air around the gyro. Momentum does affect the gyro's performance in a quick turn.

There IS a drop in altitude when a gyro makes a quick downwind turn. It is NOT the same in a fixed wing aircraft.

I wish Chuck could fly a light gyro, then he could understand that 1,000,000 hours in aircraft does not directly relate to a fast turning gyro. If he had gyro flying experience then I don't believe he would discard the downwind turn situation in a gyro.

[birdy]

Chuck E,thanks for comi'n down from the ceiling.If there is only one thing in common between you and me it's the hatered of political correctness crap,your last couple of posts sound a bit like mine on the oz forum.Only here I am trying to be diplomatic.Stuff the diplomasy,I'll say what I mean in me own language from now on.

I'm supprised by Ken's comment,"I wish Chuck could fly a light gyro."

Wot's e say'n chuck???????

Maybe I'm talk'n to the wrong bloke.

I know when I turn downwind ,in wind as strong as me air speed,it takes alot longer to do a 180 turn,without losing airspeed or altitude.[remember,I don't start with any altitude to spare.]But when I do a 180 turn upwind,it can be done in a thenth of the time and not lose airspeed or alt.
Obviosly on a calm day it don't matter which way tou turn cos there is no wind to counter,BUT,you can't turn 180 as fast on a calm day as you can into the wind.[with out loosing AS or alt.]

This I do know,I'v done it countless hunderds of times,close to the ground.And if momentum or inertia has nothing to do with it ,then what dose Chuck?????What makes the down wind turn a different story to upwind.???

Or don't you do" DANGEROUS" things like that.

[Chuck_Ellsworth]

Let me try once again to explain turns when there is a strong wind blowing.

First we must expect turbulence due to mechanical eddying of the air. that alone should give you pause for thought about doing any steep bank angle turns close to the ground.

Let me now once again clarify where from comes my understanding of this subject. I teach high command Control airplane handling and held a low level exemption for air displays in Europe. For years I taught aerial application both fixed wing and helicopter. Low level to me is exactly that, the machine is just above the ground.

As well I hold a Commercial gyroplane pilot license and cleraly, clearly, clearly understand how gyros fly and what can be done with them. Believe me a helicopter will perform manouvers you could not possibly do with a gyro.

There was a discussion some time ago on a European forum among helicopters and the down wind turn subject came up.

After weeks of discussion not one helicopter pilot could show proof that there is any difference in a turn with regard to wind alone. The concensus was there is no down wind turn loss of height in a constant airspeed constant angle of bank turn.

What you will get with a very quick turn done close to the ground in a wind is the illusion of a change in lift, any change in height will either be a subconsious change in the pitch attude caused by the opticlal illusion your brain "thinks" the eye is seeing as the apparent ground movement abruptly changes or caused by turbulence.


If I ever find that there is an aerodynamic change in lift caused "only" by turning in a wind I'll get right back here and let you all know.

In fact I'll kiss my own a$$ at high noon on stage at the next gyro meet I go to.
PS:

No, I do not do dangerous manouvers, all our low level displays or low level work is done based on proven and practiced manouvers.....thats why I'm still alive.

Chuck E.

[birdy]

Chuck,thanks for not hitt'n the ceiling.

I appreciat someone with your experiance trying to understand the mind of a simple bastered like me.

But I would also appreciate if you would try the sinario I posted earler,in a light gyro,in strong wind,close to the ground.


You may find you can rip the machine around into the wind in double quick time ,with no fear of ground strike, but I know I can't do the same manover turning downwind,with out spraying the machine onto the ground.
That is me point.

[PTKay]

Birdy,

I talked to my gurus and the anwser is the same like Chucks, there is NO difference.

They gave me a good explanation (example).

If you imagine the mass of air is like a big (and transprent) ship (let's say carrier with big deck). You are on top of, the ship is moving quite fast on completely smooth water with back wind of the same speed.

Now imagine, you are driving circles around the deck of this ship in your bike.
You obviously don't expect that turning your bike bug to stern will be different than turning stern to bug. Do you ?

You are on the deck, and relatively to this deck you do not change the attitude, no matter if it is up or down the ships movement.

That's my 2 cents.

And the "illusion" explanation by Chuck is all that makes the point.

Try: http://www.ebaumsworld.com/illusions.shtml

You will be shocked how your eyes can fool your brain.

PTKay

[Doug Riley]

Chuck Ellsworth is exactly right, in that the physics of a downwind turn in a uniform wind are the same as upwind. There are a couple subtle "buts," with which I believe Chuck will agree.

But #1: Near the ground (in Birdy country!), the wind is not uniform, but layered. The wind next to the surface hardly moves at all, because of friction. A few feet farther up, it's a little faster, a few more faster yet, and so on. If, in the course of your turn, you pass from a layer going at one speed to a layer going at another, you WILL experience an instant change in airspeed. Carrying on the analogy of riding in a train, it's as if the engineer suddenly hit the brakes. This is a type of wind shear.

(You get a favorable version of this effect when you first lift off into the wind. As you climb through the increasingly fast layers, you get a momentary burst of airspeed that you can trade for a little kick of altitude. It doesn't last, however; the gyro's speed soon matches the layer you're in and then you're back to the physics that Chuck has patiently explained.)

But #2: The "no difference up- and down-wind" rule requires you to hold a constant bank. When you try to follow a nice, even circular track over the ground, you will have to tighten the bank a lot as you come off the wind. That's what can produce the illusion that turning downwind causes you to "drop out of the sky." It's not the downwind turn that gets you, it's suddenly tightening your bank. That always requires more power to hold altitude.

Conversely, if you do manage to hold a constant bank, your ground track will be messy. As you turn downwind, your circular track WITH REFERENCE TO THE GROUND will stretch out in the downwind direction. You won't experience any unusual sinking feeling, though.

Experiment with holding constant airspeed and bank angle to verify this. Have a decent altitude, though, and don't try it when you have to watch for traffic. It requires concentrated attention to the airspeed indicator and detracts from your traffic-watching.

But #3: Turbulence is essentialy a series of changes in the wind's speed or direction that are too fast for the gyro to adjust to immediately. (The train engineer and the brakes again.) Turbulence produces changes in airspeed and angle of attack... but if, for example, you enter an updraft, the increase in angle of attack will last only a second or two. After that, the gyro again will "catch up" with the air and it will be as if there is no updraft. Until you fly out the other side, when the whole process reverses itself.

[rehler]

The ground or carrier deck has nothing to do with what the gyro does. Natually the "mind" and "visual relation to the ground" is valid and important. All pilots can see and agree with this.

But ... the "hover to turn" example above is real and is similar to the "down wind turn" loss of altitude that gyro pilot experience. It too is real.

Why don't all of you take off work, get in your gyros and try it. It's easy to experience what happens. Then come back tomorrow and let us know.

A fixed wing aircraft can't hover in the wind and make an immediate turn as fast as a gyro so the inertia of the aircraft keeps up with the turn of the wings. A gyro can turn (spin) around its rotor axis.

You guys with helicopters, please also try it and let us know. I've tried it often, so I know that a quick turn from into the wind to with the wind causes loss of altitude. A slow (normal) turn, on the other hand, is just like a fixed wing and reacts just like Chuck and other say. It's the fly in the moving jar then.

[Udi]

Birdy - you were saying that in order to turn from zero groundspeed to 100k groundspeed; you have to change the momentum of the aircraft. This is absolutely correct! Any object moving in one direction has to change its momentum when turning 180 degrees. The same happens when you turn from 50k flying going north to 50k going south. In either case, you have to change the momentum of the ship by 100k at 180 degrees.

Your actual ground speed has nothing to do with this. If I placed a black sheet of plastic between you and the ground, you wouldn't know that you were flying at zero ground speed. All you would know is that you were flying 50k airspeed. Period! Your gyro does not have eyes, so it doesn't matter to him how fast you go in relation to the ground, it only knows that you are going at 50k. If you completely ignore the ground (hard to do when you're flying at 50 ft), and only look at your airspeed, keeping a constant AIRSPEED throughout the turn, you wouldn't know if you were turning from downwind to upwind or visa verse.

Wind sheer and turbulence is a different story. If you are flying low over bushes or trees, there may be a wind gradient, or wind sheer, with altitude. So, if you were to climb from 20 ft AGL to 60 ft AGL, as you make the turn, the wind may be 10 k/h stronger at your new altitude. This will cause a momentary loss of 10k of airspeed as the stronger wind comes from your back.

Harry – Like Steven, I believe you were flying way behind the power curve. You were turning from upwind to downwind. The ground was suddenly moving much faster under you, and you naturally pulled back a little. This was enough to get you behind the power curve and the only way to stop descending is by trading altitude for airspeed. I have had this sensation with a hang glider many times, and the only way to stay out of trouble is to ignore the ground and concentrate on your airspeed.

Udi-

[Udi]

A fixed wing aircraft can't hover in the wind and make an immediate turn as fast as a gyro so the inertia of the aircraft keeps up with the turn of the wings. A gyro can turn (spin) around its rotor axis.


Ken - when you are "spinning around the rotor axis" you are losing airspeed. This will affect your subsequent airspeed regardless of your ground speed. I have hovered in a fixed wing (hang glider) probably thousands of times, and many many times, I turned into downwind without losing airspeed.

Udi-

[Chuck_Ellsworth]

Doug and Udi :

Please each of you take over for me, I can no longer spend time trying to explain basics to these very well meaning but ill informed gyro pilots.

Please start by explaining the simple fact that if you are flying at or near the edge of the flight envelope speed and power wise any change of control input will instantly change the flight path, and insufficient power or airspeed will produce the loss of altitude.

I must quit now or I will get depressed and shoot myself.

Chuck

[birdy]

Chuck,mate,don't do that,you'll make me sad. :'(

Doug,Udi,chuck and Ken,I am sorry but steven is the only one who is understanding the point.

If speed relitive to the ground has nothing to do with turning in windy conditions,then why is an upwind turn so much safer to a downwind.You never hear people gett'n caught behind the power curve and spray'n thear machine on the ground do'n an upwind turn, do you,??


Udi made the point of keeping the air speed at 50k,if you do this of course you won't loose altitude,IN A GENTLE TURN.But I'll pay handsomely the bloke who can turn his machine down wind,starting from 50k ASI, 0k ground speed ,to 50k ASI ,100k groundspeed,as fast as it can be done upwind.[and not loose alt.]

It can't be done,simple,you have to gain momentum,in order to hold airspeed,[catching up with the air]and that momentum you have to gain is in relation to the ground ,not the air,you already have 50k ASI,and you want to finish up with 50kASI.


What is wind???
It is air that's moving horisontaly or verticaly"IN RELATION TO THE GROUND."If it isn't moving IN RELATION TO THE GROUND then it's not wind.
Udi ,you said
"If you completely ignore the ground (hard to do when you're flying at 50 ft), and only look at your airspeed, keeping a constant AIRSPEED throughout the turn, you wouldn't know if you were turning from downwind to upwind or visa verse."

That is in a gentel turn,at alt.
To turn SHARPLY downwind,you ether have to add alot of power or loose alt.You can turn sharply upwind at idle and not loose alt.Why???????
The only difference between the two turns is groundspeed.

Losing alt is not my imagination,you don't hit the ground and not get hurt ,because you only imagined it.

Of corse you loose alt in a sharp downwind turn,in any machine,the harder you turn the faster you drop,because you are giving the machine less time to "catch up" with the air.[Less time to gain momentum ,which is measured in relation to the ground ]

Just get in the bloody machine and try it,any accomplished pilot can rip a machine from down wind to upwind,and I'll shout the bloke a carton if he can do it the other way in the same amount of time.

[GyroRon]

I think Udi nailed it. If your in a gyro and you whip it around in a tight turn you will lose airspeed. Lose airspeed and you will lose altitude. Go up and try these tight turns in all directions in windy conditions and calm conditions and watch your airspeed indicator. you might be surprised.

[birdy]

Ron ,accepted,the best way to burn off air speed is to throw the machine into a 90 degree bank,like dropping the ancher.

If you do just that ,throw the machine into a 90 degree bank,and turn from upwind to downwind,you will drop like a brick.[no airspeed]Now do the same, downwind to up wind and you don't loose any alt.Why????[Go try it ]

[Heron]

You guys are making me sick! :-
You are not talking about the same thing, how do you intend to make sense?
Chuck, I will take a pound o salt for you in Sao Paulo . . .
And do not shoot your self, take a gyro up, do a very tight turn downwind and splat youself at the bottom of the air mass you were previously flying in.
And you are now in debt with me . . .nothing that a ride on the Big Flying Boat can't fix.
~!@#$%^ :(
nite!
Heron

[birdy]

Now we is gett'n somewhere. :)

Thank you Ron,Steven and Herron,for pointing out the obvious.

We were argui'n two different things.I noticed on page four that the sinario wasn't read properly,I'v never said on this thread anything about coordinated turns with maintained airspeed.{I didn't bring this up because I didn't want to be shot down again,you blokes understand eachother better than us simple cow growers] ;)

Explains a bit what I said befor about experts not understanding us simple people. >:(


I think some now know what me point is.
The reason why I restarted this thread was because my perception of what was explained meant there was no difference turning up or downwind.

Taken to the letter,by a simple bastered like me ,would mean it is safe to do so.Simple bastereds like me wouldn't consider the alt loss in a tight turn.[untill it was too late.] :'(

My intention by restarting the subject was to get the "newbs" to understand the dangers of turning down at low altitude.

I hope I'v succeded cos I'm tak'n me bat n ball and goi'n home now. :(

[Did I hear a sigh of relief??] ;D

[Aussie_Paul]

Hey Birdy, I am in there with you!!!!! LOL

Chuck, my good mate, you may have a gyro rating but you do not know how and what can be done with a gyro!!!!.

I totally understand and agree with your explanation, BUT that revolves around co-ordinated balanced flight.

A gyro is so nimble that a lot of the rules are broken. The old exception to the rules maybe.

At Bensen days 1999 I did my Raf required check flight with Jim Logan. Now Jim had come up through the police helicopter situation. Jim was a great check pilot, but did not know how to really handle a gyro.

I was used to being on Base leg, cutting the power back to zero, judging the turn and landing on the numbers. Jim liked to approach at a descent rate of 500 feet per minute with power as he would with his police helicopter.

I went for a ride with Duane Hunn, he and I had grown up with the early gyros where engine failure was expected. Duane said that he would love to put Jim in a 72 hp Mac powered Bunsen!!!!!

I really enjoyed flying with both those gentlemen. Different styles due to different backgrounds.

That is what we have here. Chucks responsible big machinery flying, and Birdy with his race around trees chasing cattle work requirement flying.

I am arguing all the time with people, including Birdy and manufacturers re pitch stability.

The problem with these people is that they have never experienced flight in a truly pitch stable gyroplane. Their only experience is flying gyros with varying degrees of instability, so how could they comment when they have never flown a pitch stable gyroplane?

I was in this same category in 1999. Remember Chuck E?

S**t, I made a fool of myself many many times but the patience of Chuck Beaty, and others, has seen me through. Now Chuck and I have some differing opinions on a couple of things but all in all it has been a wonderful experience for me, and I hope that Chuck B has enjoyed my challenges to him.

Not many of the Oz guys appreciate the testing that I have conducted during the last couple of years, but there will be a number of people on this forum who used to wait to see what tests I had conducted and what the results were.

I think that Greg Grimminger enjoyed the comparing of stick fixed testing experiences that he and I conducted on different sides of the world. A lot of people like to put their 2 cents in BUT they don't do the hard testing yards.

There is a lot of hard work in conducting the tests to gather the data required for the ATSM sub committee.

Enough for now.

Aussie Paul.

[Heron]

Paul The Aussie:
I have this HUGE brick that flies (don't ask how) and if I do not coordinate turns in a way that the RATIO OF TURN is kept to a minimum, it will loose AIR SPEED and consequently loose lift, falling like a BRICK.
And if I am too close to the ground before regaining the optimal speed I will dig a hole in to the pavement.
What else ??
Heron

[mrford61]

From reading many of Birdys posts I suspect that his gyro in fact is an extension or replacement of his dirtbike. It is not a means of aviation, it is a tool,and Birdy is no more an aviator than an astronaught. (absolutely no disrespect Birdy!!) In fact I share your fear of heights.

Birdy is doing a job close to the ground and using the ground as a reference because the ground in his case is his immediate threat.

Chuck and co. are indeed aviators and aware that in aviation the ground has no relevence as a reference and no bearing on flying anything.

I have spent thousands of hours in choppers as a spotter mustering cattle and those (worlds best) chopper pilots are very aware of the "downwind turn"

[Chuck_Ellsworth]

I was not going to post on this subject again.

However:

What concerns me is the "preception" of how aircraft fly that seems to be evident among some gyro pilots.

My benchmark for total missunderstanding of the subject of flying goes back to my first experience with a gyro pilot.

When I was first introduced to him I was told he was the best gyro pilot in the world.

The truth of course was the exact opposite, he was a self taught gyro operator with zero schooling and zero understanding of the very basics of flight and any other subject related to flight.

He was the president of RAF and as part of my deal with RAF he was given authority by Transport Canada to train me for my gyro license...It lasted three flights and I refused to fly with him due to my fear of being killed.

His authority to teach was short lived as Tansport Canada cancelled his temporary authority to teach.

He went on to support my opinion that he was incompetant by continuing to smash up his RAF's on a regular basis ending in his last flight which killed him and two other people in another gyro that he ran ingo during a filming flight.

So I get really nervous when people try and convince me that they are capable of defying the rules of safety and have figured out aerodynamics and physics of flight that the rest of aviation have never experienced.

Chuck E.

[mrford61]

Well Steven theyre your words, not mine.

Who says Birdy would be "rising" in rank. To aviator may be a step back for his application.

I guess the point I was trying to make is that Chuck is irrefuteably correct in terms of aviation.

Birdy is irrefuteably correct as a mustering pilot.

I wasnt setting standards.

Cheers.

[birdy]

Paul,
The point I'm talk'n about here has zip to do with stability.

The worlds most stable machine will make just as big a mess on the deck if one tryes to turn down without enough daylight between his cheeks and that deck.

Please don't lull your students into a faulse sence of security about stability in these circumstances.

Mark and Steven,
Maybe I'm not an aviator,have no idea what I am,but I know I'v been doi'n it a while and am still alive.

And chuck,I'm still to smash my machine through poor judgement or lack of understanding of it's capabilities.In fact,my understanding of the caperbilities is the only reason why I can do what I do and am still alive.

Ignorance won't save your neck, only save you the worry of the dangers.

[Harry_S.]

Right on Steven;

Maybe you could ease the irritation by ignoring the irritant.

[Chuck_Ellsworth]

I guess I just do not have to right personality nor the right stuff to post on this forum because it seems that some posters in this group find me to be below their social strata, Oh well so be it.

The fact still remains that gyro pilots as a group are considered to be in the fringe area of sport flying due the the public perception that they are wreckless and ill trained with regards to aviation regulations and rules.

So for those of you who are offended that I have the wrong attitude no problem, I will probably keep reading about how another gyro pilot smashed up their machines while ignoring all the rules of safety and normal decision making process that just keeps this sport on the bottom of the radar screen for the general flying community.

I have no intention of jumping in some simple gyro and attempting to fly it beyond what my own ability and common sense dictates would be foolish.

So have at er boys, show me just how good you can fly.

I'll keep scanning the news to see how it goes. ;D

Chuck E.

[bogman]

Contrair Chucky :) Some on this forum find you to be way above their social strata.


Your knowledge and experience is valuable to all of us. You gotta remember though that most of us are just weekend warriors, not professional pilots.

We have to juggle families and jobs to find time to enjoy this sport. Most of us can't spend the time to get or afford the training that you have.

We come here to hopefully pick up a nugget or two of some useful information and to share experiences.

We may be ignorant of technical knowledge but we aren't stupid. We tend to assimilate more of whats being said if people talk to us like we didn't just crawl out of a cave. ;)

So please don't give up on us, just relax a little.

[mrford61]

Mrford61:
Much better.
My apology for jumping so harshly to Birdy's defense.
Steven


Steven, cheers mate,
My post did come across a bit ambiguous.
Never was great at putting my thoughts into words. DOH!!! :(

It was actually meant in Birdy,s defence.

Over and out.

[GyroRon]

I think if Chuck posted more often and had more positive posts, his occasional negative jabs would attract less negative attention back at him.

[Chuck_Ellsworth]

Hi Ron:

First off I was really distressed to find out that your Pacer got wrecked, did you get it fixed yet?

As far as my posts go hell I'm not here to win kiss my ass awards for being PC. I only try and point out that there are rules of safety and common sense that dictate how long you may live when you fly any flying machine.

Regardless of the physics and aerodynamics involved there are sane limits that come into play when flying,,,,and low level clipping the grass quick turns are just plain dangerous even without wind.

Anyhow I'm up to my ass in new inquiries from people wanting airplanes moved and type ratings so I probably won't have much time to post here anyhow.

PS :

We just took on a contract to get a PBY airworthy for flight that has been parked outside for eight years.

Once we get it safe to fly we will deliver it from London England to Tel Aviv Israel via France, Italy, Greece, turkey, Cyprus and into Israel.

Don't worry thanks to reading this forum I am now fully aware of the danger of down wind turns so chances are I wont wreck the f.ckin thing before we get it delivered. ;D ;D



Chuck

[bogman]

Well Steven if you want the experience conveyed in a way that will be easily taken by everyone, we will need the help of a true posting expert to teach us.

Where is Craig Wall when we need him? ;D ;D

[Whirlydog]

Wow, I see this thread has started up again. I have been in Eurpoe the past three weeks and have not had a chance to read and catch up on what has been happening here.

I believe there are good ways to make turns and bad ways to make those turns. Yes if we keep a CONSTANT BANK AND CONSTANT AIR SPEED we should not see any loss of altitude ( the good way to make turns).

I also believe that we can make turns very quickly and and the momentom or inertia of the aircraft will cuase us to loose airspeed and altitude becuase we could be flying backwards so to speak and it will take a period of time to regain forward motion and air speed. I think this is what Birdy was getting at.

Let say we are in our car at the race track we can go into a banked turn stay on coarse and at the end of the turn be headed in the oposite direction and never loose speed or control. Now lets say that we are in the staight away and want to reverse I direction on the track. if we can whip that car around 180 deg,
the car is going to want to continue in the same direction it was going. We are now going backwards, we floor the gas and it will take a period of time before we see the car moving forward again. What just happened is one of Newtons (I think it third) laws, that a body in motion wants to stay in motion.

Now lets apply that to gyro flight. It is my understanding that we can change the direction the gyro is pointing in very quick measure, thus be flying backward due to our previous forward momemtum, and momentarily loosing airspeed and altitude. We should expect to see this requardless of wind conditions.

I don't know how long it will take the average gyro to recover from this manuever, but lets say that it takes 2 seconds on a calm day now wind. since we have lost some airspeed we can expect to loose a little altitude also, I dont know how much but for sake of argument say 25 feet per second that it take to regain forward momentum and airspeed. In this seneario we would drop 50 feet and back to normal flight.

Now let see what happens when we apply a little wind to the factor. First lets go back to the car senerio. Drivng uphill could be the same as flying upwind. and driving downhill the same aquivelent of flying down wind. IE. it takes more power to drive up hill than down hill, the same should apply to maintaining a certain ground speed in the gyro. also if we were to maintain a certain power level in the car we would go up the hill slower and downhill faster, thus in our gyro we would maintain airspeed but our ground speed would change dependent on direction. We can also say tha the steepness of the hill is porportional to the effects of windspeed to the aircraft.

Now we are driving our car up a steep hill and whip a 180 turn. it will take a shorter time before we would see the momentum stoped, the direction changed and speed build back up. Going down hill it would take longer for the montem to stop, direction changed and the time to get back up to speed.

Now if we are flying in the wind and whip out that quick 180 turn, the time it takes the aircraft to stabilize will or should be different depending on which direction we turn. I we make that turn into the wind we have the wind blowing through the rotor blade in the right diection for lift and it take a lot less time to stop the inertia and build up airspeed ( same as the car going up hill doing the 180 and heading down hill). The effect of the gyro going downwind would be the equivelent of the car make the 180 while headded down hill. thus it will take longer for the gyro to regain airspeed and loosing altitude until it does regain airspeed.

Again yes we can make turns with out loosing airspeed, and should try to make our turns in such a way to maintain airspeed, but we need to be aware that becuase a gyro can make such a tight turn we could easily loose airspeed, and the direction and speed of the wind could increase or decrease the natural effect of doing such a manuever.

I hope I am on the right track here. The main thing is we should be tring to increase our understanding, get the right training, and maybe save a few lives

Shawn

[Doug Riley]

Shawn: Your reference to the wind "blowing through the rotor" is where the fallacy lies. Some folks also think you have to hold rudder "against the wind" when flying to a destination that's across the wind from your starting point. Both are untrue.

There is no "the wind" when you're flying. Wind (a steady one at least) is a huge block of air. The block may be moving over the surface of the earth, but you and your craft are INSIDE the block, like a fish in a fishbowl. The block's movement relative to earth is irrelevant to you. You and your rotor don't feel it, any more than you feel the 1000 mph rotational speed of the earth when you're standing at the equator.

The physics of reversing your direction in the air are not equivalent to making a turn in car on a hill. They are equivalent to making a turn on level ground. Again, the fact that the ground is moving as earth turns or the fact that the whole planet is screaming around the sun doesn't affect your car's turn.

Birdy and others in similar lines of work (such as crop dusters) must constantly maneuver with respect to objects on the ground. Therefore, their downwind turns have to be tighter WITH RESPECT TO THE AIR than their upwind turns. If they did a constant-bank, constant airspeed turn downwind, the movement of the block of air they are in would result in their drifting downwind from their target. That's why those low downwind turns can put you into a wicked sink.

People get in trouble in downwind turns in airport patterns because, by definition, these patterns are flown with reference to the ground. Your downwind turns must be extra tight to maintain a nice rectangular path over the ground. If you could see your path through the air while doing this, you'd recognize that a neat rectangle with reference to the ground is a lopsided mess with respect to the air... and it's your motion through the air that determines whether your rotor can make enough lift to hold you up. Only your motion through the air produces "wind" thorugh the rotor. Mother nature's wind is undetectable when in flight.

[Whirlydog]

Doug, not to argue with you, but I thought my reasoning and logic was pretty sound. If I am wrong then I am wrong, but it may give us something to think about and possible explain why a few people have died making such a move.

I am here to learn.
Shawn

[Doug Riley]

Shawn, the wind does not "blow into" the rotor unless you are on the ground.

When you ride an escalator, once you're aboard, the stairs do not continue to come up from behind you and whack you in the heels.

Carrying your goldfish in its bowl on an airliner going 500 mph, the goldfish does find it difficult to swim in circles, even though half of each circle is upwind.

Driving in your car, you don't have to struggle to reach forward to tune the radio, even though your hand is travelling "upwind."

Your car analogy was working OK until you threw in the hill. A hill on the ground is the same as a hill in the air: a climb or a descent. Your hill analogy applies to a discussion of climbing and descending turns, but not to level ones.

The wind does not "blow against" your airplane if your destination is at a 90-degree angle to the wind. You don't have to hold rudder, slip the plane, fly one wing low or do anything else odd. Don't look at the ground and you'll never know by the feel of things whether you're going up- down- or cross-wind - because aerodynamically there's no such thing. These concepts are as meaningless to the rotor or wing immersed within the moving block of air as they are to the goldfish.

Honest.

[Udi]

Shawn,

Nobody says the downwind turn is not a real problem. Many people have got into trouble, and some even crashed on a downwind turn. This is a real enough problem.

What Doug, Chuck E., Ron, Me, and a few others are saying is that, if you fly the gyroplane (or airplane) WITHOUT looking down to the ground, you wouldn't know you were turning into upwind or into downwind. The aircraft doesn't care that the wind is blowing ON THE GROUND.

The downwind problem is related to people who fly their aircraft, using the ground as reference for airspeed. Doug explains this very well in his post. When flying a gyroplane low and slow, it is hard to ignore the ground. When you are turning downwind, looking AT THE GROUND, you may have the sensation that you are accelerating - simply because your GROUND SPEED is accelerating. If you are ignoring your airspeed indicator and are looking only at the ground for reference, you will pull back on the stick because you feel like you are going too fast. Pulling back on the stick, you are slowing (slowing – means airspeed!) the gyro behind the power curve and, as a result, you will be losing altitude quickly. You don't know why you are losing altitude because you have full power and you are moving with a good speed over the ground.

There is no contradiction between what Doug and others are saying and the fact that people get in trouble in a downwind turn. They get into trouble because they use the ground for airspeed reference, or because they are trying to fly with a certain track to the ground. Not maintaining airspeed while flying close to the ground is one of the biggest mistakes a pilot can make.

Udi-

[GyroRon]

Chuck go ahead and be the bad boy of the forums. But it would be nice to see more postive postings from you. Besides the RAF bashing and the stuff in this thread, what other positives have you contributed to the forum? Look don't get pissy with me, I really don't care how or if you post. Just offering a opinion that I am sure is shared.

Thanks for asking about 1107Charlie. Last I heard the wings were to be on and all paint work done by the end of this week. Then it is a matter of getting the engine back together - waiting on the crankshaft to get back from the shop - and then finishing the annual and she will be back in the air where she belongs. I expect - no make that hope - to be going to pick here up before the end of April.

The rest of ya need to go up and practice this whole downwind turn stuff. It is just as Doug and Udi explained.

[Chuck_Ellsworth]

O.K. Ron :

I have thought it over and of course you are correct, in 125 posts here I have contributed nothing of value.

You will be pleased to know that I have decided to have no further input here.


Chuck Ellsworth

[jucie]

Hey, Chuck, come on. Nobody wants you to leave.
Countless times I had read that people do appreciate your messages, as I do.

Take it easy, ok? Be cool.

[CLS447]

Goodbye Chuck. Man ,I wished that he would have built & flown gyrocopters!

[GyroRon]

No I would like Chuck to stay as well, I have gotten used to his rude insulting comments and they don't bother me personally anymore.

My point I was trying to make is, Chuck is on and off here on the forum, and when he is on 90 percent or more of his posts are either rude or negative in tone and or nature. AND that is fine by me, I am not the forum master or police. Some of my own posts are viewed as negatives - even when or if they were never meant to be seen that way.

But when Chuck comes back from his breaks doesn't anyone else notice how bitter and negative most of his posts are? Just look at all of his posts from the last 2 weeks. SO...... All I did here was to offer up some advise that perhaps if he contributed more positive postings here that maybe the Positive to negative post factor would be closer to 50 percent or better - instead of the 90-10 percent he has now. It is my honst opinion that if he had more positive things to say more often, people wouldn't get so bent up when he tells you to kiss his ass, or to pound salt, or that your a retard and he is the best pilot there ever was.

He doesn't have to, nor should he, leave cause of my posts here in this thread. I am only trying to help.

But isn't it funny how he can tell you to pound salt and to go to hell and so on, but offer some advise his way and he is no longer going to grace us here with his presence???? Come on Chuck just get with the program and lets treat each other here with a tad more respect. No one wants to see you leave, and just the same No one here wants you to tell them to pound salt either.

[KevinKing]

Ron, you would have loved Craig Wall. Chuck has been quite polite compared to him. Hey Craig, are you out there?

Come on Chuck, don't stop posting just because a few people think you're rude. I can't speak for anyone else, but I value your input.

[GyroRon]

Kevin I had dealings with Craig. He and I got into it about two years ago when I was new to the forums. He would go off the deep end on you, and your right Chuck is angel compaired to Craig. But in the end I would rather deal with Craig than Chuck because craig got involved on a positive level with a lot of the discussions here and he was a big help to many.

Chuck I saw your other post. Don't go away just cool your temper a bit and jump in more often and don't be so negative. Your input to the forum is valued by many, just check your ego and attitude at the door and try to have a little fun when you post here. We are in this sport - flying gyroplanes - for fun, not for business and that should explain alot of it.

[Whirlydog]

Hi Guys, I am back from a long weekend, Sorry to hear Chuck is disenchanted with us, but oh well.

Chuck, Even if GOD was to answer question on this forum I am sure there are some that would question and argue what he had to say also. Myself included.

None of us are God, so let us continue to question and argue in a constructive and repectful manner and I am sure we can all learn things.

For the more timid people out there if you have questions or a theory, don't be afraid to ask it, or presenting your ideas, becuase this is how we learn.

Doug, Ron, Udi, and everybody esle thanks for bearing with me and my theorys and questions. I may still question things here, but what I need most is to get some time in the air. Again Thanks everybody.

shawn

[Harry_S.]

Craig vs Chuck. Craig knows gyros. Chuck does not.

[Chuck_Ellsworth]

Yeh Harry :

I don't understand anything about aviation, so maybe you could educate me?

I find I just can't resist comoing back here, debating with people like you and Ron and a few others is sort of like slowing down on the highway to rubber neck a wreck, I really have no personal intrest in it but just have to look. :D


Chuck E.

[Heron]

heheheheheh :)
It is like a short circuit isn't it Chuck?
They post. . . . you jump . . .;)
CArry on guys . . .carry on!!
Heron

[Blll]

Hey Folks...

There is ONE difference between a gyro vs either a helicopter OR an airplane that might pertain to this discussion....

Airplanes or helicopters MUST use their wings/rotor blades to change their direction in an airmass....moving or not.....

A gyro can spin about its rotor axis....and use the thrust from its engine to change direction...and when that happens you

1....quite providing the thrust/drag that keeps the rotors working at the neccessary rpm

and

2....your using your propellor to change direction in the airmass rather than proper reorientation of the rotor system....not a wise way to do it since the rotor system is many times more effective than the propellor in that regard

take care

Blll

[Chuck_Ellsworth]

Yeh, Heron:

I guess it is like a short circuit... :D :D

But it wouldn't be as entertaining if I just ignored some of these posters.....I have not seen much proof of exceptional skills or exceptional qualifications to teach all these subjects being posted by those who seem to find me not their kind of guy though. And I'm sure Craig is really impressed.

I have attended several gyro gatherings in the 90's and met a lot of nice people.

Seems that there a few that may not be so friendly towards me if I ever went to another one..but I guess those are the breaks.


However I think I'll struggle through all this without any real damage to my normal life. :D :D

Chuck E.

[Heron]

Yeah Chuck I think you are going to be okay too!
For those outside this kind of argument in the forum it is all very funny and enternaining, ITOH those envolved suffer somewhat (high blood pessure, increase in pill dosage and . . .) :)
A little fat to chew is always good and keep things alive.
Just do not go in to this quiting mode of yours again, ok?

Many good things come out of this Forums and in the end is all good, i tend to like evryone, just my friendly, sarcastic, ironic self.
thanks
Heron

[CLS447]

Chuck E. , I am very sorry. I must have missed your posts on building & flying. How is your LW coming along? What has been your favorite gyro that you have flown to date?

I agree that the gyro is the easiest aircraft to build & fly. That's why I'm into them. I also think that they are the easiest to store & transport & maybe afford. They are also the most fun! So please , Let's treat them as such, & leave the negative stuff for people who WANT to hear it! Thanks. We would love to see pics of your new project or even that dusty old RAF!

[ToddP]

I was just browsing NTSB reports and came across this one, seems to fit into this thread:

NTSB Identification: MIA93LA172 . The docket is stored in the (offline) NTSB Imaging System.
14 CFR Part 91: General Aviation
Accident occurred Saturday, August 07, 1993 in OKEECHOBEE, FL
Probable Cause Approval Date: 6/30/94
Aircraft: LOVE, SANFORD W. DOMINATOR, registration: N44162
Injuries: 1 Uninjured.
THE PILOT STATED HE WAS FLYING NORTHBOUND AT 200 TO 300 FEET, AT 50 MPH WITH A 25 TO 30 KNOT SOUTHEASTERLY WIND. THIS WAS 5 TO 10 KNOTS SLOWER THAN HIS NORMAL CRUISE SPEED. HE MADE A TURN TO THE NORTHWEST WHICH PLACED THE GYROCOPTER DOWNWIND. AS HE COMPLETED THE TURN THE GYROCOPTER BEGAN TO DESCEND RAPIDLY. BEFORE RECOVERY COULD BE MADE THE MAIN ROTOR CONTACTED A PALM TREE AND THE GYROCOPTER IMPACTED THE GROUND. THE GYROCOPTER THEN ROLLED ON TO THE RIGHT SIDE AND CAME TO REST. ROTOR RPM WAS NOT MAINTAINED DURING THE TURN WHICH RESULTED IN THE RAPID DESCENT.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:

THE FAILURE OF THE PILOT IN COMMAND TO MAINTAIN ROTOR SPEED WHILE REVERSING DIRECTION.

[birdy]

Hmmmm...............,Reckon I'll just lurk some more.

[Greg Mitchell]

Birdman....all sounds a bit familiar..whadaya reckon? Lookin forward to Bond Springs and jousting with Brutus?

Mitch

[Harry_S.]

Chuck:

I don't think any one doubts you have thousands of hrs. PIC. And as a CFI.

How many hours do you have as PIC of gyroplanes?

My point is; aviating a gyro is very much different than aviating a fixed wing.

Aviating a gyro is much different than aviating a helo.

I'm sorry if I mis-understood that you were a gyroplane CFI. If you were, I stand corrected.

[Heron]

Todd:
Tha report has to be wrong, You see . . .aircraft should maintain level flight because the air bubble does not care what the aircarft is doing, it just moves and the pile of metal goes along with it!
That pilot is a terrorist! He is conspiring against some very knowledgeable people that knows better . . .
Gosh . . .
Heron

[birdy]

An example of the upwind/downwind turn situation I origionaly posted is now on vidio,and if there is no difference between the two turns I'll eat my f@#k#@g hat.

[Harry_S.]

Birdy'mate;

Where's the video? I'm anxious to see it.

I was flying the other day in a 25 mph wind. I was heading upwind towards home when I saw fit to do turns around a point. I'm wondering why I lost a
100 ft. when my turn went downwind.

Birdy, can you make turns about a point without looking at the point? On the ground that is.

[Doug Riley]

There is no difference in the physics of flight among gyros, helicopters, fixed-wing planes and other craft that use airfoils to create lift. They all accelerate air downward and employ the reaction from this activity as lift. Whether any of these craft will stay up or fall down depends on two things: (1) the amount of air accelerated in a given unit of time and (2) how much it's accelerated.

However good the NTSB is at investigating airline and train crashes, they know nothing about gyros. For example, past reports from the NTSB have attributed gyro crashes to "loss of tail rotor". The report quoted here riduculously attributes settling out of a turn to "loss of rotor speed." As we all know, as long as the rotor is experiencing a load of one G (or more), RRPM can't decay and can't even be controlled by the pilot. OTOH, airspeed IS under the pilot's control and CAN be lost.

Airspeed is more likely to be lost in a level, downwind turn if the pilot is watching the ground to guage his speed. It's CERTAIN to be lost unless considerable power is added, IF the pilot needs to carve an accurate circular path over the ground -- that's the case in cattle mustering and also in flying airport patterns. Hence, pilots doing these activities must understand that a ground-referenced downwind turn is going to require extra airspeed and/or power.

If your turn is performed with reference to a specific circle on the ground, a downwind turn will require tightening your bank as you proceed. This, in turn, requires more power. If you haven't got the extra power, your airspeed will be used up instead and down you'll go.

OTOH, hold a constant bank and airspeed and ignore the ground and you won't be able to tell downwind from upwind. Neither will your gyro.

[Chuck_Ellsworth]

Harry S.

Next time there is a 25 knot wind try your turn around a point and do not change your bank attitude or your power setting. Just to make sure turbulence will even out any altitude variations do your turn around a point for five minutes.........let us know what happened.

Then get back to me and let me know why your altitude remained the same.

A "Smiling Jack" type.

Also known as Chuck Ellsworth

[Harry_S.]

Doug;

The last two paragraphs in the above post said it all. This is exactly what we have been trying to get across.

There ARE times when you must look DOWN. 1) Turns about a point.

[pwendell]

Boy, I can't believe this thread is STILL going on and on and on.

How are downwind turns different from upwind turns?

1. I will assert that while performing a moderate, steady banked turn there is absolutely NO difference.

2. While flying with REFERENCE TO THE GROUND, e.g. while 'mustering' or flying the pattern, there are two significant and related differences.

a. When turning onto the downwind, GROUNDSPEED increases. This can cause a pilot to, unconsciousely, add back pressure to slow down and end up on the back side of the power curve losing altitude.

b. Because GROUNDSPEED increases while turning downwind, it is necessary to steepen the turn to keep a constant distance from an object on the GROUND. The steeper bank requires more power to maintain altitude. If one is already at max power, e.g. during climbout, one will loose altitude.

3. This is the controversial difference. When making a rapid turn to downwind, which gyros do so effortlessly, it takes a finite amount of time for the wind to accelerate the gyro onto its new vector. The greater the wind, the longer this time will be. During that time, the gyro will experience a loss of airspeed and a resultant loss of altitude if power is not added to compensate.

For me, the really important thing to remember is that all of these factors have a tendancy to come together. For example, during the downwind turn in the pattern, the pilot is flying with reference to the ground and may unconsciousely add back pressure to slow down while in a steep turn to the downwind leg. Since many gyros will still be at full power while turning downwind, the untrained/unaware pilot might run out of options quite rapidly. In addition, because there are several factors contributing to the same phenomenon -- losing altitude while turning downwind -- it can be difficult for the pilot to determine exactly what is causing it, thereby leading to many bizzare and false explanations.

Just my two cents.

[Dean_Dolph]

Doug, I posted a message on this subject under 'just a bunch of hot wind' in the General forum that I would appreciate your comment on.

In that message I did lose sight of automatic rotor rpm maintence in a 1g turn so what I posted may be completely off base.

[Doug Riley]

P. Wendell, you were doin' great until you got to #3. There most certainly is an acceleration going on when you execute a turn, whether it's upwind or downwind. (An "acceleration" is a change of velocity -- which means a change in speed, direction, or both). In a turn at steady airspeed, the acceleration is a change of direction only. A given number of degrees per second of turn involves the same amount of acceleration, upwind or down.

It's not the WIND that changes your direction or speed. The wind doesn't "blow past the gyro". The gyro is immersed in the wind and feels no wind. What changes your direction is a force that YOU create by tilting the rotor toward the center of the turn.

When you use the rotor in this way (pulling you around your turn), you're giving it extra work to do. It must both hold the gyro up in the air and have enough force left over to pull you through the turn. The steeper you bank, the faster you'll travel through your turning circle BUT the more rotor force is diverted from holding you up to pulling you around.

The rotor must speed up to accomplish both tasks at once. To speed up, it extracts energy from the gyro's forward movement. If power is available to replace this energy, you'll continue flying level. If you have insufficient power, the extra demands from the rotor will either slow you down or force you to dive. The more rapidly (in degrees per second) you travel through your turn circle, the steeper you have to bank and the more likely you are to have insufficient engine power to stay level.

[Harry_S.]

Chuck E;

I don't believe you know what you posted.

In a 25 kt. wind, there is no way to do *turns about a point*, concentric turns that is, without changing bank attitude and power changes. Turns about a point require a constant radius from the point.

To do what you suggest--not change bank attitude or power setting--which in essence would be co-ordinated turns--for 5 min., I believe I would be somewhat downwind of my *point*, if still airborne. I usually fly at 4-500 ft. and within 5 min. I could be kissing the ground, but I wouldn't allow that to happen. I will do it at altitude.

I will execute what you suggest tho, and report back.

How 'bout some of you experienced drivers do the same and report back? Those of you who fly in a windy area, that is.

[Chuck_Ellsworth]

There is a very simple formula for figuring the load factor as angle of bank is increased.

15 degrees = 1.04 G
30 degrees = 1.15 G
45 degrees = 1.41 G
60 degrees = 2.0 G
75 degrees = 3.86 G

Getting the picture yet?

Anyone notice what happens to load factor as you pass 60 degrees of bank?

Chuck E.

[Harry_S.]

Chuck;

That's real important to us gyro drivers!!

[Udi]

The information Chuck provided is only important for pilots who wish to understand why their gyro needs more power in turns, and how the angle of bank affects the required power to maintain level flight. For all other pilots this information is totally useless. I happen to be one of those geeky pilots who is actually interested in this kind of info.

Udi-

[Chuck_Ellsworth]

Harry_S :

With all due respect the laws of physics and aerodynamics apply to all flying machines equally.

I am beginning to understand that you may have some emotional issues with aviators who may be more qualified and knowlegable than you,

May I suggest that there may be many new commers to the gyro community that would like to be informed about the laws of flight that the rest of aviation accepts and uses to guide their operation of all flying machines.

And may I respectfully suggest that ignorance of these subjects will put others at risk thinking that these laws do not apply to Gyros.

By the way gyros are the most simple and basic of rotory wing aircraft but ignorance of aerodynamics and physics can prove fatal, even in gyros.

Maybe a review of all the fatalities in gyros, and the causes of said fatalities will shed some more light on this subject for every gyro pilot.

Chuick Ellsworth

[Harry_S.]

Chuck;

On this, I agree with you.

[birdy]

Harry,mate,the vidio footage is in town with the bloke who wants to make a propperly cut DVD or tape.
I'm begini'n to tyre from repeat'n meself on this forum,I'll just leave it up to the evidence on the film to do the talk'n.It appears there are some here that don't want to belive that there may be someone that may know something that they don't.Espesialy if that someone is just a simple cow grower.

It don't bother me if the nonbelivers don't want to understand,I couldn't care less about them,God couldn't convince these people.

The only reason I'm persevering with this crap is for the newbees.Some of them may be interested in the other point of view,which comes from a compleatly different feild of flying.


PS;Chuck E,
Those figures would only apply to coordinated turns,right???{I hope so,coz when I rip into a 90 degree bank I reckon 3.8G + would tear the head off me machine.] Them's interesti'n numbers all the same.

[Chuck_Ellsworth]

Birdy :

Yes, those numbers apply only to a co-ordinated sustained turn.

We do manouvers in airshows that "appear" to be very steep turns, but you can unload the G load by changing the vector of the manouver with use of elevator for one thing.

The very bottom line is knowing what your machine is capable of and not exceeding your or your machines limits.....

That is obviously how you fly your gyros or we would not be having this conversation.

I will not get into the physics as they do not change, only perception changes.

You take care and fly in your own limits.

Chuck

[Al_Hammer]

Part of the fascination of rotorcraft is that the dynamics of the rotor are so much more subtle and complex than the fixed wing.
A 60 degree bank generates a 2.0 g load factor, which can be calculated as 1/cos(bank angle)
Rotor lift must double in order to sustain level flight.
Rotor RPM increases according to the square root of the load factor. Square root of 2.0 =1.41. If normal RPM is 350, it will increase to 494 RPM.
As a rule of thumb, the power required to turn the rotor(autorotative power) increases as the CUBE of rpm. Thus, to support a 2 g turn, requires 1.41 cubed or 2.8 times the power of level flight.
This additional autorotative power is achieved by pulling back the stick and increasing the flow through the rotor. Throttle must be added to overcome the additional drag in order to maintain airspeed constant in the turn.

Beyond 60 degrees it gets "interesting"...

For a 75 degree steady state bank angle, the load is 3.86 g's
Once again we can calculate the increase in rotor rpm required to sustain this load. It is sq root of 3.86 = 1.96
Rotor rpm must go from 350 to 350x1.96=687 RPM, theoretically.
The power required is proportional to the cube of 1.96=7.52 times the power.
The rotor can never deliver that much additional power, even if the engine were up to the task of providing the aditional thrust, because compressibility effects at the rotor tips start to kick in. The increasing drag prevents the rpm from getting anywhere near that required to sustain the 3.86 g load.

Note: I had written earlier that the rotor would stall. Chuck has corrected me on this. I was going by helicopter theory which predicts rotor stall based on
a formula for "stall margin."


As I was thinking about this I realized that there is a difference beteen fixed wing and rotorcraft:
In a fixed wing , back stick produces a more or less linear increase in lift due to to the increase in AoA over the wing.
In a gyro, back stick increases disc angle, which does not increase blade AoA as much. Most of the wind the blade sees is coming from rotation, not from up flow. Increasing disc angle increases airflow through the rotor which in turn adds power and increases rotor rpm. The rpm goes up as the cube root of power and the lift goes up as the square of rpm.

Bottom line is the "lift slope" of the rotor is about 1/10th that of a standard airfoil, as I recall. That means the lift increase caused by pulling back the stick is much less than for a fixed wing.
Got a headache yet?

[C. Beaty]

I believe, AL, the limit of rotor thrust is determined by the onset of compressibility rather than stall.

As the blade loading is increased (consider axial flow; a vertical descent, for example), the outer portions of the blades begin to encounter shockwaves and a rapid increase of profile drag. The slope of the drag curve becomes so steep that the rotor behaves like the friction governor of an old time wind up phonograph.

A farther increase of load doesn't proportionately increase rotor speed and it will eventually stall as load continues to increase.

Thick, highly cambered airfoils begin to generate shock waves as low as mach 0.5, depending upon angle of attack.

[Harry_S.]

Chuck B;

Welcome aboard.

[Al_Hammer]

Thank you , Chuck. :D I stand corrected. I've changed my post somewhat to remove the questionable portion.
In a helicopter, the rotor would not slow down with increased drag as long as there was sufficient engine power to maintain rpm. At some load point the rotor will stall, whereas in the gyro the drag will simply limit the rpm. I should've thought of that. :eek:

[GyroRon]

Bout time! Thanks for joining us Chuck Beaty! :)

[Al_Hammer]

Steven, thanks. I'm glad to be the one that Chuck replied to in his first post to this forum. ;)
I would guess(and its only a guess) that the ultimate sustainable g load would be somewhere between 2 and 3, probably closer to 2 than 3.
If Chuck is right about the compressibility thing, then the rotor simply can never spin fast enough to do more than that.
If it could, then it would probably stall anyway. Many helicopters reach max load at around 80% VNE and the rotor will in fact stall if too much load is pulled, such as trying to pull out of a dive or a loop.

[Dean_Dolph]

Yeah, Ron, it is good to see Chuck B. here. But now I need to prepare to get a new printer before I had intended. I wore out one on Norm's conference printing out the little bits of wisdom that Chuck and others posted. My poor printer was just barely keeping up with Doug, Al, Greg G. and others and now throwing Chuck into the mix is going to cause it to have at least a nervous breakdown if not a physical one.

[C. Beaty]

Helicopters, Al, run their rotors at constant speed so as not to blow up the engine or over stress the rotor system. There is merit to having a helicopter equipped with a 2 speed transmission; low gear for hovering and low speed flight and high gear for high speed operation. This idea is discussed at some length is Shapiro: "Principles of Helicopter Engineering."

Gyroplanes, on the other hand, allow their rotors to run at whatever speed is necessary to carry the load. The tip speed of a properly pitched gyro rotor is very near to the square root of blade loading times 66.

Tip speed also sets the rotor limited top speed. Top speed will be near 35% to 40% of rotor peripheral speed in which case the cyclic stick will be on or near the forward stop if there are no other intervening factors.

Where required top speed in in the vicinity of 100 mph, the ideal blade loading is 35 lb/sq. ft. of blade area (not disc area). With 35 lb/sq. ft., tip speed will be 35^0.5 * 66 = 390 fps.

The hogs seldom have sufficient blade area and many run as high as 75 lb/ft^2 which results in a tip speed of 572 ft/sec, already at mach 0.52 with shock waves a-nibbling; especially when some forward speed is added. Not too much left for high Gs.

Lightly loaded rotors (blade area, not disc area) can pull surprisingly high G loads.

[Al_Hammer]

Steven, just to confuse you further, here's a snippet of a post by Craig Wall on Flygyros that brings up a couple of points not covered so far(such as the effect of blade pitching moment) It is in the context of designing for top speed, and he is referring to Ken wallis's use of smaller rotors.


quote
... Wallis is running where he should be. Nearly everyone else is "over-rotored". He does push the limits of tip speed, but he didn't just *do* it- he worked up carefully. He's not your average Joe-Schmoe gyronut.

35 lbs/square foot blade loading is a figure that has, for our range of gyros, been shown to be the best compromise between disk loading and tip speed. It has been arrived at both empirically and theoretically for the airfoils and speeds we typically fly. For any more details, please consult Chuck Beaty or read Raoul Hafner's works.

For myself, I trust that figure because while lighter DISK loadings have lower drag, they also have less margin above tip stall due lower RRPM , and gust sensitivity...and at the other extreme, higher DISK
loadings have higher drag and a lower margin above Mach problems. Having BLADE loadings above 35 lbs give too much tip speed for the correct disk loading, while low BLADE loadings for correct disk loadings give pathologically low RRPM.

Again, for the optimum tip speed, consult Beaty or Hafner. The point here is to reduce the advancing blade drag by keeping the speed as low as possible while still maintaining a proper margin above retreating blade stall, or, more to the point, preventing the appearance of an overly-large stalled region inboard on the retreating side, which causes the disk to fly at an excessive AOA due to flapping. It also causes the advancing blade to have a substantial NEGATIVE lifting region at the tip.

So, that's what the correct tip speed and blade and disk loading do- they minimize flapping, optimize the disk AOA, reduce both negative lift and total drag on the advancing blade, and optimize the stalled region on the retreating blade FOR THE CHOSEN TOP SPEED. That's the key- you have to know what speed you are designing the machine to go, and of course the available power figures into that.

RRPM is a function of the square root of the loading- a 2-G turn gives you 1.414 times the RRPM- IF THE BLADES ARE TORSIONALLY RIGID, which of course they are not. If they have a slight positive pitching moment, the blades will twist to give an increased blade AOA, which will reduce the RRPM increase to something below the sq rt relationship.

What you see at these numbers, as you have calculated, is top speeds in the range of 70 mph or so with typical power-to-weight ratios. Probably the most noticeable effect is the need to hold a lot of forward stick pressure at high speeds- in fact, increasing the blade incidence too much can cause you to be speed limited by running out of stick travel. Low loadings cause low disk angle at high speeds, and the machine gets overly sensitive in pitch, even though the flapping has increased. You get negative stick gradients, and handling becomes a real issue, especially in turbulence.

If you go to smaller rotors, as Wallis has, you can get higher speeds more safely- but you must be SURE you aren't going to run into Mach problems. It does you no good to make a "brittle" machine that flies on the edge of disaster, because one day something will cause you to eat away your margin to nothing, and someone else will be comforting your widow.

It's all a compromise between performance, handling, and safety.

Craig
end quote

OK, Dean, get out the printer...

[birdy]

Now this is the sort of yabba a simple ozzy cow grower likes to read,top posting men.

Now,another one,the actual power of the gyro rotor has always fascinated me.

Just for the excersize,I'll describe my mustering machine.

170kg with 26' extruded alloy blades.

If I'm cruising at 50k,S&L and rip the machine into a 90 degree bank until the airspeed is 0 to and load the rotors with inertia,is there any ruel of thumb to roughly estimate how much power these rotors are producing????
To stop 170KG in such a short distance with a fan would require alot of power,not to mention,increasing the rotor rpm at the same time.

[birdy]

I forgot to mention me,add 75KG to the weight coz I'll be sitt'n in it. :D

[Al_Hammer]

Birdy, here is one way to estimate the power:

Calculate the hp required to change your velocity from 50 knots to zero in a certain time.

If you know the time it takes to go from cruising speed to zero, then you can use this method to get the average power produced by the rotor in that time.

Lets assume you stop the gyro in 1 sec.

First calculate the kinetic energy of the gyro moving at 50 knots (= approx 60 mph)
The kinetic energy in level flight , for a 245kg mass moving at 60 mph= 88132 Joules
I used an online energy calculator at http://www.1728.com/energy.htm

1 watt= 1 Joule/sec
So, if you stop your gyro in 1 sec, it takes 88132 divided by 1= 88132 watts.

1 hp=746 watts
so the power of your rotor in this turn is 88132/746=118 hp
If the time to stop is 2 sec, the power is half or 59 hp.
If the time to stop is 1/2 sec, the power is doubled to 236hp

So, all you need is someone with a stopwatch to observe.

[Harry_S.]

Birdy, mate;

You asked for that!!

[birdy]

Spoton Al, you blokes have good access to these formulas and it's very interesting.Thanx.
That formula estimats the power needed to stop the machine,but what about the extra power required to rev up the rotor while it is stopping the mass of the machine.To excelerate the rotors while they are under load[G force] would take alot more than 118hp for that 1 second wouldn't it.???[in other words,the heavy extruded rotors gain alot of inertia while simultaneously stopping the mass.]

[Al_Hammer]

birdy, you are right, the 118hp is the power delivered by the rotor.
More than that is needed to be pumped into the rotor because some of the energy is stored in the spinning mass. That mass is still spinning at the end of the turn with excess rpm above the normal rpm.


Here is what I would do to estimate the energy actually stored in the rotor (in the form of excess rpm) at the end of the turn.

You calculate the FORCE needed to slow the mass of the gyro to zero, based on the formula F=ma; force = mass times acceleration.

This would be the average force and wouldn't represent the fact that the gyro may, in fact, slow down slowly at first, and then more rapidly at the end as the rotor built rpm.
But it would be better than nothing.
Next, you could figure what rotor RPM would be required to produce that force.
You know that the rotor normally produces a force equal to the weight of the gyro=245kg at some rpm.
It is easy to calculate the rpm for the new force. since rpm varies as the sg rt of load change. To produce twice the force the rotor spins sq root 2= 1.41 times as fast as normal.
When you know the new RPM, you can then calculate the ENERGY stored in the blades if you know the diameter and the weight of the blades. (This where the weight of blades does come into play)
This stored energy is sometimes measured in hp-secs. That is, you've got so many hp and it will last for so many secs, like amp-hrs in a battery charge.
The R22 has about 100 hp-secs stored in the rotor at normal rpm. It takes 90 hp to maintain level flight. So you don't fly for long on what's in the rotor once the engine takes a nap. It makes for a nice flare though, right?

[birdy]

Sorry I don't have a rotor tack on this machine,it would make it simpler to work out the power but for arguments sake,if they are doing 360 rpm in S&L flight,then you do a rip turn and excelerate them to 440rpm in one or two seconds,this is a gain of 80 rpm in 1 to 2 seconds.With 50 kg blades,you would need s..t loads of power to do that mechanicaly,while stopping the machines mass at the same time.

Just think'n with me eyes shut,I reckon they would have to have at least twice the cruise power while they are reving up.The fact that they are excelerating at an amazing rate while at the same time ,stopping the machine means there has to be alot of power produced during the rpm exceleration stage
For a chopper to do this with ti's blades ,it would need heaps of power.An R22 on a hot day here is very marginal on power,and they have constant rotor rpm.For an R22 to excelerate it's blades 80 rpm in one or two seconds,even with no pitch,would be a miracle in mechanics.

[Al_Hammer]

birdy, I think we forgot to consider that the force of lift becomes a braking force when you bank hard.
Consider the fact that even if the rotor gained no energy at all, it would still stop the gyro fairly quickly.
The rotor in level flight is producing over 500 lbs of force to sustain the weight of the gyro. When you turn 90 degrees , this force is pointed horizontally and it's 500 lbs of thrust trying to slow you down.
The extra g load on the rotor does pump it up, but I don't think the gains are as extreme as you were suggesting.
The gyro would stop in around 3 seconds (off the top of my head) assuming it puts out 500 lbs of thrust horizontally. The extra energy pumped into it causes it to slow even faster, that's all.
Thanks for helping me to think it through.

[birdy]

Yeh,I see were you are coming from Al,but if they was powered rotors,how much hp would you need to make the rotors do the same thing???what I'm trying to say is,an R22 couldn't do what autorotation can to the rotors ,ie;excelerate while under load,and the R22,in power to weight comparison,is not much different.
Or am I bark'n up the wrong tree again.

[Al_Hammer]

Lets look at the R22. I think you might be underestimating it, birdy.

If it weighs 454kg(1000 lbs) and is moving at 60mph, the power required to stop it in 2 sec is about 109hp.(using same calcs as before) If we assume the rotor is producing about 90hp in level flight, it is possible to bring it up to 109hp by going to 110 percent rpm on the tach.(rotor energy goes up as the square of rpm)
This is within allowable limits if the collective is lowered and aft stick used to load the rotor.
So, it looks like it should be possible to slow the R22 to zero speed in 2 sec. by simply using the available power in the rotor. No additional engine power is needed. The rotor may try to speed up in the turn, so some collective may need to be pulled.

At the Robinson flight safety course, they demonstrate a throttle chop in straight and level flight. The collective is not lowered. Just using back stick the rpm can be kept in the green for several seconds. This proves that even at cruise pitch, the rotor can still be made to autorotate under load.

[Dean_Dolph]

Al, my printer never gets a chance to cool off. The only reason this one has lasted as long as it has is because Craig stopped honoring us with his presense. The rest of you stepped up to make up for the loss but the latest printer is tough although there have been times of late where a faint buning smell was evident. I don't know if it was from the work pace or from the printed content!

[birdy]

Now that makes sence Al,it's obvios I don't fly choppers.
If I'm read'n you right,anR22s blades could be trying to auto in a hard bank???

[Al_Hammer]

Now that makes sence Al,it's obvios I don't fly choppers.
If I'm read'n you right,anR22s blades could be trying to auto in a hard bank???
yup, I believe they could.

[birdy]

Thanx Al.
Gess that explains why I should stick to the simple gyro for this sort of work.