Bad Day at Training [Archive] - Rotary Wing Forum

Screw

11-12-2003, 11:22 AM

Myself and Scott Essex reported for training today with Steve McGowan. Weather forcast called for 5-10 wind. *Felt stronger when we got there. Scott commented on the roller coaster effect of the heavy winds and I couldn't wait to get up there. *Missed lessons due to weather twice and it had been a week and a half since my last fix. I though my training was going better than I expected considering that most of time Steve usually kept his hands where I couldn't feel them in the stick or on the throttle and we did most of our work on the taxi ways. *All was going good until today. * Today was the first time I didn't feel like a pilot. *Today, it felt more like the machine was flying me, rather than me flying the machine. *I feel like I regressed. *I didn't make but one smooth landing today and I think it was because the gyro felt sorry for me. *I could feel Steve all over the stick and throttle which was unusual, but it let me know just how badly I was doing. I only remember trying to kill Steve twice though. *Once on take off, and once on a botched landing. Don't know what happened other than it was a windy day. *Too me, the condititions weren't that bad. *I'd flown without blinking an eye. Every time I turned into the wind to approach a runway, I would ballon up about twenty feet and I spent the rest of the time chassing the back pressure all the way down. *After the gyro fell out on me a couple of times, I cured it with power and by the end of the day, Steve said I was getting too dependant of power. I didn't have any problems losing altitude turning down wind and I thought I handled that part ok. * But I know I have had a bad day when all of our flying was done on the runway rather than the taxi way. We completed 1 hour today giving me a total of 4.0 hours. I hope next time goes better :-[

GyroRon

11-12-2003, 01:14 PM

John Steves machine is very un stable in winds and thermals. He can feel it coming before it even happens. As soon as it hits one of these bugers the gyro ballons up and you have to pull power and pull back on the stick to stablize the gyro. It will take a while, just be prepared for it. You could always learn to fly in a stable gyro, But IMHO your learning to fly a hard and potentially dangerous machine.... And when you do get to solo, you will be ready for anything. To date I don't think any of Steves students have crashed or gotten hurt. Also maybe things were calmer in Macon today but up here in Charlotte N.C. the winds were VERY strong all day. So anyway has he had you fly it with your eyes closed yet?

GyroRon

11-12-2003, 01:16 PM

Watch out! Murpheys gonna get ya! ;)

GyroRon

11-12-2003, 01:23 PM

I have tried to attach a darn picture on the last two posts. I will try this one last time.  >:(

Screw

11-12-2003, 01:47 PM

Yeah Ron, I've already done some flying for him with my eyes closed...I just sucked today.  Damn Low Time Pilot >:( Your pictures aren't posting. Remember David & Goliath?

Aussie_Paul

11-12-2003, 08:41 PM

What else would you expect on a rough day with Steves machine. I gather that Steve is a great instructor. Imagine how a student could progress with Steve AND a truly pitch stable gyro. Aussie Paul.

scottessex

11-12-2003, 09:59 PM

It wasn't a bad day, EXCITING, but not bad.  Certainly can understand downwind turns now. and Ballooning, and other such things that before I  had only read about.

GyroRon

11-12-2003, 10:11 PM

WTF?

GyroRon

11-12-2003, 10:13 PM

Well my mouse worked why not my pics? they aren't over 100 kb

GyroRon

11-12-2003, 10:17 PM

Try to post another pic

Screw

11-12-2003, 10:37 PM

Assie Paul Quoted, "Imagine how a student could progress with Steve AND a truly pitch stable gyro." The whole time I was thinking, "If it's this rough in his 800lbs gyro plus 2 aboard, Wonder how bad this could have been with Da Screw-Driver and just me?"

Screw

11-12-2003, 10:42 PM

And BTW, I find find Steve to be a very good instructor.  It's like he lets us do all the flying, and guides us in letting us know what we are doing right as well as wrong.  He also cleans up what we mess up. As I mentioned before, He keeps his hands in such a way that I don't know he is back there untill I need him. Yesturday, I needed him, and sure was glad he was back there. I also agree with Scott.  It really wasn't that bad, and I did learn alot with winds.  I just don't like beating on other peoples machines, and yesterday really hurt my pride more than anything.

scottessex

11-12-2003, 10:52 PM

That is why we are paying someone who knows what is going on!  It was kind of hairy out there!   Every time I go for training......I realise I need MORE training. :)

Chuck_Ellsworth

11-12-2003, 11:37 PM

Scott : You mentioned down wind turns. There is a lot of confusion regarding this subject, just be certain you really do know the dangers relating to down wind turns at low altitude... The problem will be the illusion that you see, the machine has no idea of up wind, down wind or x/wind. Just a word of caution., to make sure you really understand the subject. Chuck E.

scottessex

11-13-2003, 01:11 AM

What I meant was....These type of things are much easier to understand, once experienced.   You can read about it in books, but the actual experience adds clarity. I am not claiming to fully understand anything at this point. I have been a A&P Mechanic for 18 years, but a pilot for only 3 hours!

Udi

11-13-2003, 01:41 AM

John and Scott, You are both in good hands with Steve. *I agree with Ron that there's a certain advantage to learning to master Steve's machine, especially since John is going to fly a KB and not a Dom. *Still, I don't think that your education is complete until you've also flown a stable gyroplane. *If I were you, I would make a day trip and go to fly one hour with an instructor who flies a SparrowHawk, a Dominator, or a tandem Air Command. *Just so you know the difference. Udi-

Chuck_Ellsworth

11-13-2003, 01:44 AM

Scott: No problem, it is just that there are some really fuzzy ideas about the so called down wind turn effects on flying machines. If you were on Norms site you may have read some of the gibberish that was posted there by people who have a poor understanding of the subject. Just make sure you understand that a gyro or any other object in flight behaves exactly the same up wind down wind or any other direction. The problem can be wind gusts and turbulence, these will affect any flying machine and are easy to compensate for, unless they are severe...and if that is the case you should not be flying in such conditions. Please understand that I am not commenting on you or your instructor, I'm just cautioning you about the subject. Chuck E.

Udi

11-13-2003, 01:53 AM

This is a very interesting subject, Chuck. *When talking pattern work, isn't the main problem the "wind gradient" with altitude? *The famous lethal downwind turn? *Gyros, with their low airspeed and a very steep descent angle, may be affected even more than airplanes by wind gradient. Udi-

rehler

11-13-2003, 04:52 AM

Chuck, I know that the "downwind turn" is a favorite topic of yours, so I resist commenting in fear of starting another heated forum discussion, but ... 1. *Your theory (moving mass of air) is absolutely correct. 2. *My fixed wing experience clearly shows me that your theory is absolutely correct. 3. *My gyro experience, however, shows me that the gyro sinks on typical downwind turns, as experienced by other gyro pilots. 4. *After one of the forum discussions a year or so ago I went flying to again see what happens. *Visual reference was specifically avoided each time, but the gyro still sank when a down wind turn was done and took a little while to "catch up" to normal flight. *Not so on upwind turns. *In fact, with my eyes closed I could tell when I turned into the wind (no visual reference). So, I believe there is something to what most gyro pilots refer to as "downwind turns". I assume that you have tried such turns in a gyrocopter. *Am I correct, or just in fixed wing aircraft? I ask you (and others) to please hop in your gyro and try it as scientifically as you can and let me know what you find in actual gyro flight (not fixed wing). *Then we can perhaps determine why a small rotorcraft acts differently than the correct theory of the moving air mass, IF in fact you have the same experience as I did.

Chuck_Ellsworth

11-13-2003, 06:45 AM

For the purpose of comparison and observation. I have observed down wind turns in Gyroplanes, helicopters, very light wing loading homebuilts, spam cans and high performance jets. Note: The helicopter is far more manoeureable than a gyro. I am courious as to how you can maintain a constant attitude with your eyes closed, don't get insulted, I'm just courious about that example. Wind gradient *can be a factor, however there would have to be other factors to *consider when gradient becomes noticeable in aerodynamic changes while flying.. in otherwords it would be highly unlikely to have any signifigant lift decay through wind gradient unless there was some other instability causing factors present, such as high wind. The down wind turn is not anything special as far as I am concerned as long as the pilot understands the mechanics and physics of the fluid in which you are moving the aircraft. What is significant is wind shear and very quick horizontal wind speed changes, when these instabilities exist care must be taken to avoid sudden loss of lift. No matter if you are flying up wind x/ wind or down wind. With regard to gradient.  The slower the airspeed the more significant the loss of height for distance travelled over the ground when encountering a wind gradient change where the air movement, wind, increases in velocity with loss of height, simply because you will be in that portion of the air mass longer than if you had a high airspeed. Chuck E.

Udi

11-13-2003, 08:26 AM

Just to supplement Chuck's explanation of wind gradient - loss of lift after a downwind turn will happen only as you are climbing into a higher tailwind altitude. *If you make the turn to downwind at level altitude there will be no loss of lift. *Gyros are more sensitive to this phenomenon than fixed wing airplanes because they fly slower. * Udi

Chuck_Ellsworth

11-13-2003, 08:43 AM

Scott : Please do not take my posts in the wrong light, I was responding because you are just starting and thought that it would be good advice for you to take a closer look at flying in turbulence. May I make two suggestions? First:   Ask your instructor when you don't clearly understand any issue in your training. Second : Be sure you receive enough ground school and suppliment it with reading.. I probably would be the wrong person for you to ask anything of due to my having got off to a bad start with some of the group here, so anything I would say will be challenged because of my arrogant attitude.  Then the important issues get buried in controversy. Chuck E.

Thumpernator

11-13-2003, 01:48 PM

Don't ya just love it!! * ;D

Screw

11-13-2003, 02:15 PM

;D.

Whirlydog

11-14-2003, 01:45 AM

Oops trying to use the quote button and it didn't come out right.

Whirlydog

11-14-2003, 02:10 AM

Okay guys am am a little confused here. * :-/ * First off let me say I do not have any flying experiece so I will be talking theory. * Chuck you said, *" There is a lot of confusion regrding this subject, just be certain you know the dangers relating to the down wind turns at low altitude...The Problem will be an illusion that you see, the machine has no idea of up wind, down wind, or x/wind. *Just a word of caution, to make sure you really understand the subject". I am just trying to undstand the subject here. *If the problem is just an illusion becuase the machine has no idea of up/down/x/winds what are the dangers we have to watch out for. * This is just theory. *I thought lift was produced by wind blowing and turning the rotor blades. if this is so, then lets say that I am flying with a 20mph x/wind and turn into the wind. * If I make no changes on the machine except the direction, this is what I would expct to see. *I have in effect just increased the amount of thrust or wind blowing through the blade and this would cause the machine to lift, and the opposite would happen by turning down wind (loosing lift and sinking). * Totaly confused and trying to learn *???. * Shawn

Chuck_Ellsworth

11-14-2003, 03:37 AM

To better understand the relationship of wind effects on a flying machine, picture this in your mind. You are in a small outboard motor boat in the middle of the Amazon river on a clam day without a ripple on the surface of the water and you are beyond sight of the shore. If you lock the outboard in a turn and just let the boat circle it will carve a perfect circle and maintain the same radius of turn and speed in the water.... However if there was a line scribed on the river bottom it would draw a spiral pattern down river. Any object being flown in the air which is a liquid will act exactly the same. Conversley picture yourself in the same boat and you are now on a very fast flowing shallow river with rapids formed by the turbulence created by the passage of the liquid over the uneaven botton and you locked the boat into the same turn at the same speed. You will still make the same even radius turn in the water with the same average speed through it...however due to the turbulence and wave action created by the water flowing over the uneven bottom your boat would also be pitching, rolling and yawing in direct relationship to the degree of roughness of the water... There will also by spikes in the speed caused by the rough water. As well there can be very noticeable changes of spped related to the depth of the water. ....shallow water, high speed then as the river gets deeper the flow speed reduces. Air will react in the same manner due to changes in the pressure gradient. Now if this river suddenly met another river at a very sharp angle and the speed of the other river was faster than the river that you were circling in there would be a very quick change in direction and velocity *measured over the bottom as you traversed the meeting point of these two movements of the liquid. Not to mention the boat could become uncontrollabel due to the turbulence of the water Hope that is of some help if you did not have a clear understanding of the picture. chuck E.

Whirlydog

11-14-2003, 03:56 AM

Chuck, Thanks, the annalogy helped to explain a few things. I have a lot to learn, and will let this rattle around in my brain for a few days before I come up with my next question. Shawn

Chuck_Ellsworth

11-14-2003, 04:51 AM

When flying a rectangular circuit superimpose on your mind the Amazon River flowing at the speed of the wind. On climbout your gyro will cover the ground the same as your boat driving up stream. Cross wind picture your boat steering at 90 degrees to the shore and it will drift down stream at the spped of the current. Down wind the speed over the bottom will be the increased at the rate of speed of  the current. Base will be the same as x/wind. Final will be the same as climb out with regard to speed over the bottom.....

PW_Plack

11-14-2003, 05:07 AM

Chuck, Assuming you're not encountering a shear, when you turn from crosswind to downwind, the mass of the gyro will cause it to take a moment to regain its crosswind airspeed. Won't this produce a momentary loss of lift?

scottessex

11-14-2003, 06:03 AM

Well whatever the hell it is. you can lose altitude one way and gain it the other. So be aware, that's all. Even it is not supposed to happen or whatever, or just an illusion, I know what I've experienced so far.

Chuck_Ellsworth

11-14-2003, 08:13 AM

P W Plack : No. The gyro is flying in an air mass and its movement is in relation to its speed and direction in that air mass. Lets assume the gyro has zero air speed and zero rate of climb or descent...just motionless in the air mass. Assuming the wind speed or the movement of the air mass is 20 miles an hour over the surface of the earth. What effect on movement in the air mass would the gyro exibit if you turned it slowly 360 degrees around its vertical axis??

PW_Plack

11-17-2003, 12:11 PM

Chuck, In your example, the gyro will not be accelerated along its course, so airspeed, angle of attack and lift can all remain constant. In a traffic pattern, we have to navigate to a desired ground track. The part of this with which I'm struggling is this: In a turn from crosswind to downwind, the mass of the gyro must be accelerated to maintain the same airspeed. Unless the gyro has zero mass, that will result in some finite span of time during which airspeed will drop, right? The same thing would happen in a wind gust.

Chuck_Ellsworth

11-18-2003, 09:54 AM

Paul : The gyro is moving in the airmass and will change direction in that air mass based on the velocity and rate of change in direction that you command it to do with the flight controls. Wind is the air mass moving over the surface of the earth, once the gyro is flying in the air mass the movement of the air mass over the earth has no effect on the flight characteristcs of the gyro....unless of course there is vertical movement associated with the air mass movement over the surface caused by irregularities of the earths surface or heat induced thermals. Simply put when flying in the circuit the gyro will fly exactly the same regardless of the direction you are headed in relation to the air mass movement over the surface of the earth. I see you have a PPL Aeroplanes, do you still have the met books that you had for ground school? Maybe a review of met will clear up some of your questions. Chuck E.

PW_Plack

11-18-2003, 10:07 AM

Chuck, I do, for both the Private and Instrument ground school courses, and will see if I can find one of those great Jeppesen diagrams that (usually) makes things clearer. Thanks, by the way, for your patience in working with us low-timers!

Chuck_Ellsworth

11-18-2003, 10:52 AM

No problem, Paul. It's usually the simple things in life that create most of our problems. The understanding of aerodymanics and the atmosphere its self is some times not covered in sufficient depth or at least the basics in sufficient depth by a lot of training facilities. I see you area broadcaster, where do you work? I used to fly the traffic patrol for a radio station in Detroit with a Hughes 300 in the mid sixties. Chuck E

PW_Plack

11-19-2003, 06:00 AM

Chuck, I do morning news (and studio tech, IT, commercial production, cook and bottlewasher) for a small AM operation, KUIK, with studios located in the terminal building of the Portland/Hillsboro Airport near Portland, OR. (It's listed as a backup nav on 1360 kHz in many references.) I fly traffic report duty one weekend a year, when the airshow's going on outside our window. (As the reporter, not the pilot...so far.) The cost of flying a helicopter, along with the revenue pressures brought on by the FCC's belief that cities like Portland need 50 radio stations, have all but ended helicopter traffic reports in any but the largest markets. Most now fly fixed-wing, but stage and produce the reports in such a way that, while they never say "helicopter," listeners will assume it. If there was a way to fly traffic watch with a gyro, how much more competitive could the costs be! I'm still pondering a scenario in which a normally experimental gyro, operated under "public use" rules, could fill this role. I believe I know a way...but I think I'd have to become deputized! Here in the northwest, at this time of year, there are days when you might have VFR conditions over many area highways, but don't even have IFR minimums to get a C-172 off the runway here at the airport. I've often wondered if there wouldn't be some way to file an IFR flight plan which matched the route you'd need to fly to get around for traffic watch. Here's a good question for you, Chuck: If properly equipped for IMC, is there any reason a gyro shouldn't be eligible to receive an Airworthiness Certificate with operating limitations allowing IFR? (Assuming a gyro stable enough to be practically flown that way?)

Chuck_Ellsworth

11-19-2003, 10:36 AM

Paul : Lets address the stability and IFR item first. It is safer and easier to fly any flying machine by reference to instruments alone than by visually looking out side for attitude and situational reference. So the stability and IFR equation are really a moot point. Simply put if the gyro is stable or unstable your control finess will be more accurate when flying by reference to instruments only. There are two gyros the Mc J2 and the Air and Space 18 A ( maybe three now with the Groen Bros Hawk, which I believe is certified. ) already on the market. The cost to certify is horrendous and very time consuming. I know your airport very well as I used to fly a Rockwell Turbo Commander 790 B in there for maintenance at Aero Air. I ocasionally drive to Scapoose to visit Jim Vanek, maybe next time I do I can look you up. That is as long as you don't think I am to arrogant and a blow hard. ;D  ;D Nice chatting with you. By the way if you have any questions that are better answered in private,  e-mail me at    chuck@ellsworth.org A lot of my answers seem to get all bogged down in criictism of my manner of posting. Chuck

PW_Plack

11-20-2003, 06:21 AM

Chuck, Come by Scappoose some second Saturday of the month, and I'll buy you a share of the pot-luck lunch at the Chapter 73 meeting. It would be great to meet you, and I know there are a few members who only lurk here, but would appreciate the opportunity. The January, February and March meetings will each follow a two-hour gyro ground school session with Dave Wiley, seaplane instructor and examiner, who also holds every FAA rating, including gyroplane. We'll be meeting in the Northwest Antique Aircraft Club's clubhouse, kitty-corner from Jim's shop at Scappoose, near the fuel dealer. Class at 9:45am, lunch at noon, meeting at 1pm!

Fiesty

12-09-2003, 05:54 AM

Chuck-

You are correct in what you say about downwind turns.

To help lets take a box 4 foot square and put a fly in it.

Now carry the box around the area.

The fly will not notice any change in air movement.

He will just continue to fly around and around.

The box represents a volume of air moving in a certain direction and speed.

Udi

12-09-2003, 08:54 AM

Steven,

If Randy's box is moving at a constant speed and direction than the fly doesn't know it is moving at all. You are correct that when we just accelerate the box the fly will have to accelerate as well, but once the speed of the box has stabilized, and it can be at 100mph, the fly will have no idea that the box is moving.

This is a very good analogy to wind.

Udi

ToddP

12-09-2003, 09:52 AM

Steven,

Your example of the balloons brought back some memories. When I was in college, I worked for a florist making deliveries. When you accelerate, all the balloons rush forward, when you brake they all rush back. Man I hated that job... :-[

Whirlydog

12-09-2003, 11:21 AM

There is something about the "box analogy that I don't like, call it a closed system. We can replace the fly with a human in a big jetliner, except when the plane is accelerating or decelerating we notice no movement. Partly the reason for this is that we are in a closed enviroment where outside influences do not effect us.

The reason we feel the acceleration is becuase of newtons law, "a body in motion wants to stay in motion, and a body at rest wants to stay at rest". When the plane takes off we feel that ecceleration becuase the plane is moving, but we as a body at rest want to stay were we are. Once the plane reaches a constant speed we and the plane are moving at the same rate of speed, thus we don't feel the plane moving. Once th box is at a constant speed the fly doesnt know the box is moving beuase they are moving at the same speed compared to something out side the box. Now when we decide to slow that plane and land we feel it becuase we are trying to move faster than the plane (a body in motion...) I don't think it has anything to do with reduced or increase air pressure, becuase the air moelcule are just like us they are trying to stay at rest or motion and are forced to one side of the box determined by the change of speed of the box.

Shawn

airRanger

12-09-2003, 12:55 PM

Would another though be........

in a Hot air balloon caught in a 1000 mph
(exaggerated mph!) jet stream feel any differant? I hear not!

Udi

12-09-2003, 01:25 PM

As long as you are flying in a body of air that is not accelerating in any direction, you will not feel any difference between a windy day and a no-wind day. Unless you watch the ground that is. From the gyroplane point of view, there is no difference between a downwind turn in a 30 mph wind and a no wind day. The only difference is ground tracking.

The key to this statement is that "the body of air is not accelerating". In a sense, you are flying in a moving box.

Udi

Whirlydog

12-09-2003, 02:08 PM

I just can't see how turning upwind/downwind is not going to effect how the gyro operates. Just by changing the direction of flight in a windy condition you have just changed the enviorment that it was currently flying in, and the AC should see it as having just increased or decreased thrust.

Using Chucks analogy of a boat on water. We are on a calm lake we apply power what happen to the boat? The bow should lift as we apply power and lower when we decrease power? In an AC I would expect forward movement and increase lift as I apply power, and the opposite as I decrease Power. Am I right so far?

Now let us put this boat in a wide moderate moving river (no rappids). I am traveling across the river then decide to turn upriver. Will the bow of the boat raise/ stay the same/ or lower if I do not change the speed of the engine? I would expect it to raise, and I would expect an AC to increase in lift. I would expect the opposite if I turn down river.

I could care less about the acual position in reference to some land point. By changing direction in the wind or river or what ever enviroment you want to use, are you not also changing how the object reacts or sees its new enviroment?

Can you expain to me how the wind does not increase or decrease the amount of thrust and or lift the AC is feeling?

Perhaps if you can explain the basics of how lift is generated. we can progress from there.

Shawn

PS. Has anyone ever tried to fly a kite downwind? Is it even posible?

Udi

12-09-2003, 02:47 PM

Shawn,

You have to free your mind from the earth!!! A kite is tied to a string, which is fixed to earth. Cut the string from the kite side and the kite will fall back to earth as quickly as if there was no wind.

When you fly at altitude, your aircraft doesn't give a damn whether the mass of air it is flying in is moving relative to the ground or not. Your speed in relation to the ground is meaningless. When you are flying, the only thing that matter to the gyro is your airspeed.

I will give you an example.

You are flying north at 50 mph. At your altitude, the wind is steady from the west at 50 mph. Your ground speed is 50mph north and 50 mph east, that's 70.7 mph northwest. If you have a GPS or if you look down, you will see that you are flying northeast at 70.7 mph.

Now, you keep flying in the same conditions and suddenly you pass over a layer of clouds. You can't see ground anymore; you can see only clouds below. The clouds are moving with the wind too. Looking down, you see that you are flying only north, not northeast. You, and the clouds, are carried inside the air mass we call wind RELATIVE TO THE GROUND. But when you can't see the ground, you don't know that there is any wind. So, when you fly over the clouds, your visual reference is exactly the same as if you flew over the ground in a no-wind day. You will see that you are tracking north at 50 mph relative to the clouds.

Now, still over the clouds, you are turning west. Your visual reference over the clouds will tell you that you are still flying 50, going west over the clouds. But your ground speed will be 0. You are flying 50 inside a mass of air that is moving 50 in the opposit direction. When you turn from north to west, will there be a 50 mph rush of wind, giving you a total airspeed of 100 mph? No, because before you turned west you were already moving, relative to the ground, at 50 mph going east!

As soon as you free your mind from earth you will understand.

Udi

Phil_Ruffin

12-09-2003, 06:29 PM

Seems to me that if you are flying 60 MPH in a 30 MPH cross wind and you decide to turn down wind then your forward air speed will drop to 30 MPH because you can't immediately increase your ground speed to 90 MPH to compensate for the 30 MPH tail wind you now have.

With a 30 MPH drop in air speed why wouldn't you loose altitude?

KevinKing

12-09-2003, 07:43 PM

The Earth is revolving around the sun at about 67,000 mph. At the equator, it is spinning at about 1000 mph. At noon, the rotation is opposite of the motion around the sun, so rotational speed is subtracted from the speed of revolution.

Say you're driving a car west at 50 mph, at the equator, at noon. Your speed relative to the sun (which is also moving through the galaxy) is 66,050 mph. Now, you suddenly turn so you're driving north. What happened? Did you go flying off the planet? No. The speeds of the Earth, the sun, the galaxy, are all irrelevant. For all practical purposes, the ground is completely stationary.

When flying thought the air, the only thing that matters is the air. You are moving through a stationary volume of air, and the ground is moving below it. The ground is irrelevant (except that your destination is most likely located there).

GyroRon

12-09-2003, 07:49 PM

Phil, the problem a few of you guys have is understanding that once your wheels leave the ground, ground speed is meaningless as far as your speed in the air in regards to the wind. Let me ask you all a few questions to maybe help explain.

1. If your flying into a 60 mph headwind at a indicated airspeed of 100 mph then how fast are you going through the air?

2. If your doing the same thing above how fast are you going in ground speed?

3. If your flying as above into a 60 mph headwind and your flying along as 100 mph indicated and you turn 180 degrees and now fly at 100 mph indicated with the 60 mph tailwind, how fast are you going through the air?

4. in question 3, how fast is your ground speed now with the tailwind?

If it was pitch black dark outside and you couldn't see the ground, this would all make sence to everyone. People are getting ground speed confused with airspeed.

Answers: 1. is 100 mph 2. is 40 mph 3. is 100 mph 4. is 160 mph - Look at the difference between what happens from going from the conditions in questions 1 and 2 and questions 3 and 4. you go from a 40 mph ground speed to a 160 mph ground speed, but the whole time your plane is going a steady 100 mph through the air.

Another way to look at it is using the stall speed of a airplane. Take this for example.....

your flying along in a plane that stalls at 40 mph. your flying into a 40 mph headwind. your plane can be flown slower and slower till it stalls. When it stalls you will be at a hover in respect to ground speed because the stall speed matches the speed at which the wind is passing over the ground.

But take that same plane and turn it 180 and fly with the 40 mph tailwind and fly the plane slower and slower till it stalls and your ground speed will be 80 mph because the plane now not flying but falling, is in air that is blowing at 40 mph across the ground and the plane stalls at 40.

Does any of this help?

One of the reasons I think some people get confused with headwinds and so on is from us always wanting to takeoff into the wind. What you have to understand is we can just as easily takeoff WITH the wind. The reason we don't is we will be rolling much faster across the ground ,and use up more runway because of that, to get a given airspeed in the moving tailwind. Or for example..... If your plane takes off at 50 mph airpspeed and you fly it into a 20 mph headwind for takeoff, if you could put a speedometer on one of the main wheels you would see a ground speed of 30 mph as the wheels leave the ground and the plane becomes airborne. BUT try to take off with the 20 mph wind at your tail and at 50 mph indicated where the plane will take off and fly, the ground speedometer is showing 70 mph.

mrford61

12-09-2003, 09:46 PM

Steve:
Not sure if I am right here but think the key word might be "SUDDENLY"
The first time I took off in a really strong wind I was watching the ASI like a hawk. I climbed out and started a downwind turn. It was a very gradual turn and and I maintained 40 knots indicated like a man possessed. I have no idea what the gyro done in relation to the ground because I was too focussed on airspeed. After the turn I was heading downwind at 40 knots IAS with no loss of altitude. I thought "whats the big deal". I actually thought the wind must have dropped such was the non event.
I went around again but with my new found confidence reefed her around hard with no respect for the ASI and was losing altitude at a rapid rate.
I figure in the first turn in relation to the ground I was at some stage flying completely sideways and in the second turn in relation to the ground I was stopped. ???

Heron

12-10-2003, 05:05 AM

It seems to me that a gyro has a built in climbing angle.
Wind + relative wind will create climbing ratio.
Head wind will result in more climbing than tail wind (that will possibly creat sink rate)
That's why a gyro will sink in down turns . . .or not?
That fly can out fly the box and than what?
That air mass will drag the fly with it in the direction where it is going.
Do we fly in compressed air (fluid)?
thanks
Heron

Whirlydog

12-10-2003, 06:11 AM

I am glad I am not the only one that feels the way I do.

Udi, I am trying to free my mind from "earth" and trying to understand only the effect to the AC in a given enviroment.

Let me ask it like this: let say you are flying, it is a calm day, no breeze at all, you are flying straight and level happy as can be. Then all of a sudden you hit a gust of wind head on at say 40 mph, what will be the reaction to the aircaraft?

I will wait for a few answers before my next question. If we can, lets forget about airspeed and groundspeed ect for a momment (we will get to that later), and concentrate on the expected reaction to the AC in the above example.

Shawn

GyroRon

12-10-2003, 06:21 AM

The problem Steve is this.... when we fly our gyros we are in a open or near open machine. We can usually se right between our legs to the ground, or long story shorter, we can really see the ground alot more than a little airspeed indicator.

So the problem is we get used to judging our speed by the rate of the ground moving below us. And not watching the airspeed indicator.

what can happen is when flying into a headwind we tend to fly faster than typical to try to get our ground speed back to " normal " and at that point our airspeed is higher than normal and the climb rate will be better because of that.

when we turn downwind or fly with a tailwind, the ground is flashing by below much faster than " normal" so we tend to fly slower airspeed to try to get the ground to fly by at the speed were used to seeing it go by at. With a high enough tailwind we can end up flying the gyro behind the power curve just trying to get our ground speed to match what were used to seeing on a calm day.

The real danger of the so called downwind turns, is when fairly low to the ground we go from a headwind to a tailwind, some pilots will as they make that turn allow the AIRSPEED to drop to keep the ground speed constant. When this happens the gyro will lose altitude and if low enough will smack the ground.

The fact is if you were able to go up and fly with out seeing the ground to gauge ground speed you would not see any difference between flying into or out of a headwind.

GyroRon

12-10-2003, 06:40 AM

Shawn if your flying along in calm conditions and all of a sudden hit a 40 mph gust the airspeed will - for the momment the gust is blowing - go up by 40 mph and your gyro will behave as if it is flying 40 mph faster than it was a momment before.

Typically when this happens - calm winds to a sudden 40 mph gust is rare, but wind gusts do happen - the gyro is being flown with the cyclic at a position to allow the gyro to fly at a certain speed, and with the sudden increase in airspeed from the gust the cyclic will be too far back and the gyro will want to climb. Some gyros will ballon up from this gust, but that has more to do with certain blades and airframe design.

But that is what would happen. the gyro would suddenly start a climb, the 40 mph gust on a calm day would start a RAPID climb.

the faster you fly a gyro the further forward you have to hold the stick. Most gyros with good amount of power will be limited in top spped by how far the cyclic can be pushed forward. So at normal cruise, say 60 mph the stick can still be pushed quite a bit further fowards if you were to want to fly at 100. The 40 mph sudden gust would have the gyro for at least a few seconds flying along at 100 with the stick still at the position for 60. Hence the climb.

Reverse the whole direction of the gust and flying along on a perfectly calm day and get hit with a 40 mph gust from the tail and the gyro will suddenly be flying 40 mph slower than it was a momment before. If you were flying slow enough to begin with - say 45 mph airspeed - this gust would have you for at least a second or three going only 5 mph airspeed.

Now if the gust continues and becomes a steady wind the gyro will pick back up to it's " regular " airspeed in this moving current of wind. How long will this take? I am not sure but I am sure it would be a matter of a few real short seconds.

But remember this is not a likely condition in the real world to have perfectly calm winds then a 40 mph gust.

Also you have to understand that if the gust becomes a steady wind the gyro will go back to it's trimmed airspeed in the moving air and the effect of the wind at that point on the gyro is just a varied ground speed depending on direction you fly in that moving air over the ground.

Whirlydog

12-10-2003, 07:13 AM

:D AaaH now we are getting somewhere.

Now if the gust continues and becomes a steady wind the gyro will pick back up to it's " regular " airspeed in this moving current of wind. How long will this take? I am not sure but I am sure it would be a matter of a few real short seconds

This is the point I am trying to make. During the time it take the AC to stablize and return to its "regular airspeed" it will have a tendency to lift or drop. Thus if we turn up/downwind we should expect the same tendency for a brief amount of time.

That is not to say we can.t learn to make those turns level and true. I can assume that the more gradual we make the turn, less the effect the wind would have upon us.

Shawn

Chuck_Ellsworth

12-10-2003, 08:06 AM

Shawn :

A lot of people here have tried to explain the wind and turning subject to you.

Try this.

Get a gold fish and put it in a bowl.

Then walk around in a room with the goldfish and the bowl.

Then get back to us and let us know what effect the direction you were walking had on the gold fish in the bowl when it turned from one direction to another.

Chuck

Udi

12-10-2003, 08:24 AM

Shawn, you almost got it... Ron explained very well how a gyro would behave in gusts. Your question about a 40 mph head gust was good, but you are missing the point.

When you turn from crosswind to downwind, we assume, there are no gusts and certainly no 40 mph wind shear. The mass of air that you are flying in is not changing speed. Therefore, when you make the turn your aircraft will not see any change in airspeed.

Phil, when you are flying with a 30 mph crosswind, you are already being "carried sideways" with the crosswind. That's why there will be no change in your airspeed when you turn into the wind. You are not connected with a tether to the ground. You are moving with the air.

Steven, I think you got it man! The dreaded “downwind turn” happens due to wind speed gradient. When you make a climbing turn into downwind, you MAY in fact climb into a faster moving air mass. Then, the aircraft really is losing airspeed until it can accelerate back to normal flying airspeed. Our recent discussions were on a much more basic level, assuming there are no gusts and wind speed gradients.

Udi

Whirlydog

12-10-2003, 08:35 AM

Okay guys I think I got it :P

The gold fish and fly example just don't work for me. I think it is an enclosed system that isn't effected by outside factors (me moving it around) I can wave my hand inside my car and a soon as I stick it out the wind will try and catch and take it off.

Here is what I think I have learned and what you are trying to say. You are moving in a mass of moving air, as you make a turn in that moving mass of air the AC will try and maintain the same "airspeed" requardless of wind direction. Becuase it is maintaining that constant "airspeed" there should be no lift or drop requardless of the outside windspeed and direction. The key here is that the AC is maintaining a constant airspeed.

I still contend that if you were to make that turn acute enough that you could momentarily encrease or decrease you airspeed and the AC would rise or drop until the ship stabilized and resumed normal airspeed. Just somethibg to be aware of, and I think Rons explanation of how we are judging and tring to adjust our air speed can have a large effect to the handling of the AC.

Shawn

PS. Stick me with a fork I'm done. Udi, Chuck, Ron, thanks for your replies this has been a good learning experice for me and hopefuly for others.

GyroRon

12-10-2003, 08:51 AM

This isn't rocket science folks! If your flying in the air your airspeed is how fast your flying through the air. Wind is the air moving across the ground. If your going 60 mph in the air - airspeed - then your going to be flying at 60 mph airspeed no matter which direction your flying.

If you could lose all sight of the ground, while flying your gyro, you would have no idea if your flying into a headwind or tailwind. The only way to know now is to look at the ground - or see smoke being blown, or to check ground speed on your GPS etc...

Sudden gusts is a whole other subject. And I would say it is safe to say that flying along and hititing a gust from the front or tail, you will either rise or fall even if only slightly and momentarily. This rise and fall would happen with any aircraft, a airplane, helicopter etc.... This is why some people would rather not fly in Gusty conditions. If the wind blew steady, Even at extreme high speed, people would fly without concern because the ride would be smooth and stable. But it rarely works out like that, it is usually steady wind with strong gusts and the gusts make the ride miserable, and challenging when landing and taking off.

Phil_Ruffin

12-10-2003, 09:08 AM

Shawn, That's the point I was trying to make but didn't I guess.

As far as being carried sideways with a cross wind, I realize that, but I don't think that I am being carried sideways at the total speed of the cross wind. Maybe some of it but not all of it.

I know when I turn down wind if my turn is slow enough for the down wind to build my air speed in porportion to my turn I will not loose altitude.

If I make that turn sharper and the cross wind is now a tail wind, and it doesn't have time to build and keep my air speed where it was, then I will loose altitude until the my gyro catches up to the new tail wind that I now have. (Man, what a sentence)

Phil

Heron

12-10-2003, 09:24 AM

MOving requires a given point to be relative to.
The air mass is moving relative to what?
Why sometimes the ground reference is used and times is not?
In a turn all the axis will be changed but the gravity axis that will remain constant. Turning will bleed of forward speed (forget the fluid) and the aircraft has to react to it . . .
Maybe some drawings could help . . .
Thanks
Heron

Udi

12-10-2003, 09:47 AM

I don't know why you guys don't get it. The air mass that you are flying inside is just like a very big aquarium, car, box, call it whatever you like, that is moving over the earth.

For you and your aircraft, flying in a moving mass of air (i.e. wind) is just like a fish in an aquarium or a fly in a closed box. The air is moved, as one large mass, by the powers that be. You are flying inside one huge aquarium.

It makes no difference how fast you make the turn. A fish in a bowl can swim forward and turn right back as you are hauling it in your car at 90 mph. Any reference outside the mass you are swimming in makes no difference at all. The movement of the moon above your head makes about the same difference to your aircraft as the movement of the earth below.

Udi

Udi

12-10-2003, 09:59 AM

Phil,

Why don't you make an experiment. Make yourself a visor that allows you to see the instruments in your gyro, and the horizon, but not the ground. Try to completely lose your ground reference. Go fly on a windy day. Climb to 1000 ft, and fly around the pattern or around a field. Fly cross wind and turn to downwind. Use only your instruments and the horizon for reference. Maintain constant airspeed. Now turn to base, and then to final. Using only your instruments and the horizon, you should see or feel no difference between a turn to downwind and a turn to final. Remember, you have got to ignore the ground and maintain airspeed and altitude. If you can go up and do the same exercise at $5000 ft, it will work even better. The wind will be stronger and your ground reference speed almost not noticeable.

Udi

Whirlydog

12-10-2003, 11:51 AM

I thought I was done. 8)

Things we all can agree on

1. Maintain air speed and the AC will maintain altitude.
2. increase/decrease airspeed, and altitude will change
3. What you are saying (and convinced me of) is that the AC will maintain its "airspeed" in any direction we decide to point it, independent of outside coditions.

What hung me up, (and mabe a few others) was that I thought you would increase/decrease airspeed when making a turn in the wind. and thus gain or loose altitude.

What brought on this whole disscussion is people who thought as I did and maybe even felt they had expierenced this lift/drop sensation.

Knowing that the AC will try to maintain a certain airspeed, the only question that has to be answered is this: Is there the posibility of temporarily increasing/decreasing airspeed while making a turn in the wind?

If there is a posibility, then all we need to know, is that we need to learn how to turn keeping a constant airspeed.

If this isn't a posibilty, then an explantion is needed as to why some people feel the AC rise or drop when making these turn.

Shawn

Now I am done :P

rfi

12-10-2003, 02:11 PM

If you make a very abrupt 180 degree turn in a gyro from a headwind you will lose altitude momentarily. A gyro can make a steep enough turn that you lose airspeed when turning downwind. I know of two people who sank into the ground from a hundred feet altitude after making a steep downwind turn after a takeoff at Albuquerque.
The reason is that your ground speed in a head wind is your airspeed minus the speed of the wind. Let's say that you take off in a 30 mph headwind and are doing 45 airspeed. Your ground speed is only 15 mph.

If you make a steep turn downwind your ground speed is still 15 mph and the wind is blowing at 30 mph from behind you so you have minus airspeed and the ship will sink since you have no air blowing through the rotor.

It will continue to sink until you have picked up sufficient airspeed. In order to maintain the 45 mph airspeed your ground speed is (45+30) = 75 mph.

One should never make abrupt turns at low altitude with a strong headwind unless you want to live dangerously.

rfi

12-10-2003, 02:12 PM

Chuck_Ellsworth

12-10-2003, 02:25 PM

Please, Please, Please.

The time has come for some of you to go to a proper flight training school and take a ground school course.

Seems that no matter how simple a lot of posters try and explain this subject the message is not getting through.

Like the law of gravity the laws of the fluid called an air mass do not change... no matter what you think the flying machine is doing.

Chuck E.

Al_Hammer

12-10-2003, 03:27 PM

I guess when the smallest thing you fly is the size of a B-52 bomber it is hard to understand what the problem is with a downwind turn. 8) 8)

If you've ever seen the video of Cmdr Wallis tumbling head over heels in his Little Nellie gyro during a demonstration, it's a good example of getting caught by a downwind turn, exactly as Don described.
He climbed out straight ahead and then made a quick 180 rudder turn or cropduster's turn or whatever you want to call it.

At this moment the engine happened to quit and you could see him drop like a rock. Of course, if he'd had power he could have regained airspeed and flown out of it, but the point is that it is to be expected to lose altitude if you try a stunt like that.

A conservatively flown pattern will allow you to maintain a steady airspeed through all turns, but in a gyro, the pattern is often flown quite close in.
In many cases because of restrictions about flying over houses, etc, a strict ground path must be followed.
In this case, it is unavoidable that the pilot reference the ground in order to stay within the confines of the pattern. Even worse is the case of a gyro making low passes over the field as is so commonly seen. The turns at each end can be fairly sudden.

An extreme example is a gyro pilot practicing hovering in the wind.
If she :D should be so ignorant as to suddenly turn 180 degrees while hovering 10 ft over the ground, what do you think is going to happen?
So, yes, if you keep your eye on airspeed and add power as needed to maintain altitude in all turns, you will be fine in normal circumstances.
-But flying low and slow and yanking a gyro around a small field don't be thinking about goldfish in a bowl please or you will be eating dirt like Cmdr Wallis did.(and luckily he walked away.)

Chuck_Ellsworth

12-10-2003, 03:46 PM

Al :

Lets take the "hovering into wind example and move it from low level to say five thousand feet.

To " Hover" into wind is not really hovering, only a helicopter will hover, but fo the sake of gyro talk it appears to hover when flying into wind at the exact speed of the wind, yes the ground speed is zero so it appears to be hovering.

Now back to five thousand feet and we fly straight and level at the same low airspeed and maintaining an exact altitude as in the hovering example.

If you suddenly turn steeply or rapidly, what happens to your altitude?

Al_Hammer

12-10-2003, 04:04 PM

Actually, Chuck ,isn't hovering , by definition, maintaining a fixed position relative to a spot on the ground?
I mean a helicopter hovering over a spot in a wind is really no different than a gyro hovering over a spot in the wind. Of course a gyro cannot hover in no wind. But I don't meant to get caught up in semantics.

I don't know why you moved the altitude to 5000 ft.
At 10 ft it is pretty clear that if the tail is turned 180 by a suden application of rudder, that the gyro is going to smack the ground when its airspeed goes from plus 30 mph to -30(minus meaning coming from the rear).
Maybe if the pilot was clever enough to push the stick way forward as he turned 180(to incline the disc into the wind) and had an engine that could reverse thrust he might stay in the air.
At 5000 ft he will also lose altitude until it able to regain airspeed, but I notice you said what happens if he makes a steep turn? I am not talking about a steep cooordinated turn, but rather a skidding turn.

Heron

12-10-2003, 04:04 PM

Ok I am the little golden fish . . .
Starting to like my owner going crazy and walking around the house with my bowl in hands.
Then I start to get confy with his pace and go really close to the glass and turn rapidly . . .he stops abruptly when I am mid turn . . .I will smash my little nose or but in to the bowl!!!
You took the mass speed out of the equation and my solid body moment of inercia is to strong for me to compensate with my littel fins . . .
Forget the ground and the wind they are not the main reason for sinking.
Thanks
Heron

thallett

12-10-2003, 04:10 PM

"suddenly turn steeply or rapidly" Right on, Chuck. And if you can't see the ground you can't tell whether you turned UPWIND or DOWNWIND.

Chuck_Ellsworth

12-10-2003, 04:34 PM

Yeh Tom :

I hesitate to post to much here because I tend to get my n.ts caught in my key board sometimes.

But if we all just stand back from the buzz words and examine the subject objectively it is really just simple common sense.

First off don't be stupid enough to fly agressively at low altitude, and if you are dumb enought to do it in windy conditions and kill your self it ain't gonna matter what part of the physics you were ignorant of.

You are still dead.

Chuck

Al_Hammer

12-10-2003, 05:17 PM

Well put, Steven; and very diplomatic :-*

One thing to think about: your right hand rotor blade turns downwind as it becomes the retreating blade, and what does it do?

It loses altitude i.e. it flaps down.

Chuck_Ellsworth

12-10-2003, 05:28 PM

Steven, with all due respect lets objectively examine wind gradient.

Wind gradient is a change in speed over a given height, met forecasters difine gradient when there is a vertical change of speed of six knots or more per. thousand feet.

So yes, technically a gyroplane if flown very close to its lower power curve limits if quickly turned downwind can be affected by wind speed change and also the vertical movement of the air.

So rather than split hairs it is better to just agree that any low level turn that is performed at a critical airspeed and power configuration is to be avoided.

And if it is windy common sense should dictate that more caution be used.

Chuck E.

Chuck_Ellsworth

12-10-2003, 05:44 PM

Al :

Are you building a Helicycle?

And with regard to helicopters, I do have different flight envelopes with regard to wind and low level turbulence between a light R22 and a heavy S61, however the thought process is not really a consious thing , its more subliminal due to the vast difference in how the two machines behave in those conditions.

Chuck

Al_Hammer

12-10-2003, 05:54 PM

Yes, Chuck, I have a Helicycle nearing completion.

I have also listed it for sale, due mainly to financial constraints, if you're interested:

http://was.kewlhair.com/hammer/chopper/ForSale.htm

Chuck_Ellsworth

12-10-2003, 06:14 PM

I would be interested if I was in better financial mode...

But right now I am still behind the power curve financially, I am planning on welding up a little Wing this winter, then I'll have to sell something to pay for an engine.

gyromike

12-10-2003, 07:05 PM

But right now I am still behind the power curve financially, I am planning on welding up a little Wing this winter, then I'll have to sell something to pay for an engine.

An organ?

"Pardon me sir, may we have your liver?"
"But...but, I'm using it!"

Apologies to Monty Python.

PW_Plack

12-10-2003, 07:15 PM

Actually, I happen to know that Chuck is eyeing the Rotec radial, in which case, he might consider donating an organ to get one.

Or, you might say, he "has his heart set" on a Rotec.

Chuck_Ellsworth

12-10-2003, 08:27 PM

No Steven.

You probably read that on Norms forum.

That was sposted by Bruce Bindon, and if you don't know who he is you are far better off.

Chuck

Udi

12-10-2003, 09:18 PM

I can't believe it... Al? You too?

Just when you think you know someone...

Go figure.

PEOPLE !!! I have news for you.

THERE IS NO WIND IN THE SKY.

Everyone repeat after me...

THERE IS NO WIND IN THE SKY.

There is only wind on the ground. When you are flying, THERE IS NO WIND.

NO WIND IN THE SKY

Why is that so hard to understand???

By the way, Chuck, you are wrong too :P Close to the ground there may be a significant (i.e. 10 knot) wind gradient due to ground contour, and/or obstructions, like a tall tree line. The dreaded downwind turn is not an invention, it actually is a known phenomena that's claiming a few lives a year.

OK. One more time. Repeat after me:

THERE IS NO WIND IN THE SKY

Udi ;)

Chuck_Ellsworth

12-11-2003, 07:12 AM

Udi :

I am for the sake of this audience trying to explain this subject in as simple a manner as possible...

You and I can I am sure agree that the "air" is a fluid that has the capacity for movement, expansion , contraction and heat dissipation or heat absorbsion.

These qualities of "air " create what we see as "weather" which constantly changes due to the ability of air to "move".

We could therefore by using the example of "gradient" which is a fact , also caution that a gyro when flying downwind at low level and at the wrong end of its performance envelope if quickly turned up wind encounters a difference in air flow caused by a very local phenonema sp? can lose altitude and crash..

Thus we have the dreaded up wind turn???

Now I must go to the airport and drive some rivets.

Chuck E

Whirlydog

12-11-2003, 07:24 AM

Guys,

THIS IS A SAFETY ISSUE!!! As Don Parham pointed out, people have DIED not understanding the issue at hand.

You can say "there is no wind in the sky", or "its a law of physics, and you can't change physics" all day long, and maybe that is true. But something is happening that has and will claim lives and we need to know what that something is.

I believe this something was discribed by Ron in my question about hitting a gust or sustained wind, again illustrated by Don, and backed up by Al. Steve and Phil told how they expierenced this phenomena.

Udi, You asked Phil to do an experiment the next time he went flying. I will ask the same of you, and you can come back with your findings. On the next windy day you can fly get up to 1000-5000 feet so you can olny bump into a cloud, and with out changing your throtle settings make a few abrupt turns every which way and tell us what happens to your airspeed and altimeter readings. I would welcome any CFIs willing to do this, and let us know of your findings

Let us make this a safety concern and not just a debate.

Shawn

Chuck_Ellsworth

12-11-2003, 08:34 AM

Shawn :

What you are suggesting is something that has been done for one hundred years, i.e. learning about how things fly.

For you to suggest that we go up to altitude and perform the manouvers you suggest makes no more sense than we also learn how to walk again before we head out to the aircraft.

May I once again suggest that you either receive some basic ground school on this subject or read some books relating to the subject.

With all due respect you must do some background research before you come on this forum and suggest that we are not aware of "safety" regarding this subject.

Quite frankly you have been given sufficient information from this group that you should at least grasp the answer to the "experiment" that you are suggesting we do.

Chuck E.

Udi

12-11-2003, 08:51 AM

Yes, Chuck, I know. There are a few levels of discussion going on at the same time. I just wanted to mention, to you, that loss of lift in a downwind turn is possible; although for other reasons than we discuss here.

Shawn, you asked if I can do the same experiment I asked Phil to do. Well, I can report hundreds, actually thousands (maybe tenths of thousands?), of downwind turns. The most compelling kind I can tell you about, for the purpose of this discussion, were in a hang glider. Hang gliders are turning 90% of the time during cross-country flights, and about 20% of the time during ridge/mountain surfing. When soaring in hang gliders, you are flying very close to the stall speed, because that is the speed in which you have the best sink rate. I have made quick 360-degree turns in winds that were stronger than my airspeed. If what some of you are saying is correct, I would have been stalling all the time.

My confidence is not based on theory alone, I've been flying different aircraft for 25 years.

Udi

Whirlydog

12-11-2003, 09:05 AM

Chuck,

It is becuase of conflicting info on this subject that I asked for the experimant. I believe I have a good grasp of the issue. Becuase people can die, by making the wrong move, that is why I am calling it a safety concern.

I am not impling that you are unsafe or that you don't have other peoples safety in mind.

But when you have a few people that are saying there is no wind in the sky and others that say wind is effecting how thier AC operates then someone is wrong.

Asking for the experiment can only help to prove which side is right. I think we need poof at this time and not theory. that is why I asked Udi, and any CFI to do this experiment so that repected people can give us facts and not opinions. I am sure people will trust thier findings above that of a lowtime pilot or me.

Shawn

Udi

12-11-2003, 09:05 AM

One more thing, Shawn. I know exactly why some pilots feel the way they do about downwind turns. It's very simple, and Ron explained this before. When you are flying a gyro close to the ground, your ground speed is much more "visible" than your airspeed indicator. Some people don't even have an airspeed indicator.

So what happens when you turn quickly from upwind to downwind, your groundspeed is changing from say, 30mph (if you are flying 50 and there's a 20 mph head wind), to 70 mph. If you ignore your airspeed indicator, you get the sensation that you are accelerating very fast. Some people will instinctively slow down, and find themselves flying behind the power curve.

The only way to recover from flight behind the power curve is trade altitude for airspeed. Therefore the loss of altitude, and therefore the deaths of those whom were silly enough to make this error at low altitude. Any experienced pilot knows they must ignore any external speed indication if you want to stay out of trouble. That's why we have airspeed indicators (holes in the helmet for hang glider pilots).

Udi

rehler

12-11-2003, 12:22 PM

Udi, you stated: "The most compelling kind I can tell you about, for the purpose of this discussion, were in a hang glider."

This does not relate directly to the question concerning gyrocopters. Aircraft with wings have a constant connection with the moving air mass. Rotorcraft do not. The rotorcraft blades cut through a new piece of air with each revolution. With each revolution the craft is then riding on "new" air.

So, the inertia of the rotorcraft mass wanting to continue to move in the same direction has a significant effect that does not affect any fixed wing aircraft to any appreciable degree. The "downwind turn" safety problem is a gyro problem. It is not a fixed wing problem. Fixed wing airplanes do not sink like rotorcraft in a 180 degree downwind turn.

rehler

12-11-2003, 12:39 PM

To add to my above post:

If a helicopter is flying straight and level quickly turns 180 degrees with the tail rotor, the craft will continue going in the same direction (helicopter now flying backwards). It then will takes some time for the craft to start flying forward again in the new direction. This does not occur in a fixed wing airplane.

I believe this inertia with rotorcraft (without fixed wings) is the cause of the "downwind turn" problem experienced with gyrocopters, and which is not believed by experienced fixed wing pilots. It goes completely against their training and experience in fixedwing aircraft.

Udi

12-11-2003, 01:16 PM

Ken, all inertia-related phenomena that affect the gyro in a downwind turn will be the same in an upwind turn. The only exception to this rule is when you encounter a wind gradient due to climb or descent. In other words, if you climb into a back wind, you will momentarily lose airspeed. The same thing happens to fixed wing, although they may be less sensitive than gyros.

I would bet you $100 that, as long as you maintain altitude and airspeed, you would not see any difference between a downwind turn and an upwind turn. This has nothing to do with the type of aircraft you are flying, just basic aerodynamics.

Udi

rehler

12-11-2003, 01:26 PM

Udi,

I won't take that bet! Yes of course. It is loss of "airspeed" that causes the sinking problem.

If inertia causes the gyro to continue in the same direction, this reduces the gyro's airspeed - thus the sink.

And yes it is the same upwind and downwind, but the safety issue only applys to loss of lift - the downwind turn.

Udi

12-11-2003, 01:31 PM

Ken, explain please why, in your words "the safety issue only applys to loss of lift - the downwind turn" if the same inertia rules apply to upwind and downwind turns?

I knew you were not going to take my bet - YOU ARE GROUNDED ::)

Udi

Chuck_Ellsworth

12-11-2003, 01:48 PM

Shawn :

OK I can see where you are coming from....

So we can get one of the CFI's to go up and prove these things....

I wonder why after having been a CFI and then going on to teach advanced flying for over forty years I have been missing so much about how to fly and how aircraft react in various weather conditions?

Anyhow I will get the hell out of this discussion and leave it to someone else more qualified.

And I also may as well just tear up my US Commercial Gyroplane license because the FAA issued it without really checking that I actually understand the issues relating to safe flight.

Chuck E.

Phil_Ruffin

12-11-2003, 06:02 PM

Udi, Chuck,
I understand where your coming from on a lot of points.

Chuck, You talk about flying a 5000 ft. I don't know to many gyro pilots that normally fly at that altitude. I don't fly at 5000 ft. it takes all the fun out of it for me. I usally fly around 1500 to 2000 ft. But a lot of the time I am at 800 to 1000 ft. depending on the safety factor of the ground below. I live in the country with a lot of open spaces. The people I fly with on occassions also fly at these altitudes.

Udi said:
So what happens when you turn quickly from upwind to downwind, your groundspeed is changing from say, 30mph (if you are flying 50 and there's a 20 mph head wind), to 70 mph.*

Here's what I think may be causing my altitude to drop in a down wind turn, and yes I use my altimeter and air speed guages so I know I do lose altitude.

I undedrstand Udi's statement, I fly at around 55 to 60 MPH air speed, about 1/2 to 3/4 throttle. In my experience which granted is no where near what a lot of you guys have, is that my gyro will not go from 30 to 70 in the blink of an eye. When I make a sharp down wind turn it takes my gyro a moment or two to get to the 70 MPH air speed. So I am losing altitude until I build that speed.

This sort of concurs with Kens statement:
If a helicopter is flying straight and level quickly turns 180 degrees with the tail rotor, the craft will continue going in the same direction (helicopter now flying backwards).* It then will takes some time for the craft to start flying forward again in the new direction.

Udi also said:
I would bet you $100 that, as long as you maintain altitude and airspeed, you would not see any difference between a downwind turn and an upwind turn.

Sure if you maintain altitude and air speed you want notice any difference.

I can do this as long as I gradually increase throttle while I am turning down wind.

Phil

GyroRon

12-11-2003, 07:55 PM

Phil, either you are missing something, or are having a hard time talking with the keyboard. ;)

What Udi was talking about was GROUNDSPEED. Your ground speed in the example condtions, Flying your gyro at 50 mph AIRSPEED, with a headwind of 20 mph.

Remember the gyro is in the air flying WITH the wind. It doesn't see it as a headwind or tailwind. Only objects on the ground see it as a headwind.

So here you are flying at 50 mph in the 20 mph headwind. IF you look down and were to track your ground speed you would only be going 30 mph, ACROSS THE GROUND.

So then you decide to turn 180 and go back where you came from and now you will be in a 20 mph tailwind so to speak.

Your still flying along at 50 mph AIRSPEED on your airspeed indicator and if you weren't watching the ground you wouldn't know there was any wind. But since your flying along at 50 mph THROUGH the air, and that air is moving across the ground at 20 mph, your GROUND SPEED is now 70 mph.

The danger to all this is like I and Udi explained earlier. If your real low and flying into this type of conditions, you get used to seeing the ground pass under you at the rate of 30 or so mph while flying into the " headwind". But that is fine because your flying THROUGH THE AIR at 50 mph which is well above the powercurve or minimum speed for safe flight......

But as soon as you decide to go the otherway and whip a 180, you go from flying into a headwind to a tailwind. And this is perfectly fine. BUT if you did nothing to adjust your speed or alititude and kept a steady airspeed through your turn, the Ground speed will rapidly accellerate. Why does the ground speed accellerate? because your now flying in a mass of air that is moving across the ground at 20 mph in the same direction as you as flying THROUGH that same mass of air at 50 mph. This gives you a ground speed of 70 mph.

Now here is the safety part or danger part. If you allow yourself to on some level use ground reference to gauge your airspeed - and you most likely won't be doing that on purpose but in such a open machine as a gyro it is hard not to - you get used to seeing the ground flash by under you at 30 mph as your were flying into this wind. when you turn 180 and go with the wind your ground speed will want to go to 70 mph. BUT the danger part is you will automatically feel this increase in speed as a increase in AIRSPEED and either back off the throttle or pull back pressure on the stick or both. And in a sence what you are doing is slowing down from 50 mph airspeed to a slower speed to end up with a ground speed that looks simular to what you were just doing a minute ago - which was 30. So your flying at 50 mph, with a ground speed of 70 mph, but your seat of the pants airspeed indicator that uses your eyes following ground references says HEY I am going WAY too fast!!!! And you want to slow down the gyro to what your seat of the pants indicator felt a minute earlier. And so you try to replicate the a GROUND speed of 30 mph as you were doing before you turned downwind. BUT do the math guys..... If your doing 30 mph ground speed in air that is already going 20 mph in the same direction, that leaves only 10 mph for indicated airspeed in the gyro. At 10 mph your gyro is going to be a dropping! If your too low to the ground your gonna hit the ground and hard!

Anyway a good portion of the people inj this thread are not gyro pilots yet. But to those who are PLEASE for your own sake go up and try some turns into headwinds and tailwinds and experiment a little for yourself. Try turns bothways maintaining the same AIRSPEED all the way through the turns and I will bet money you don't go up or down in altitude. Try it again using a gps or some other way to fly the turns using ground speed and you will see a loss of altitude in a downwind turn and a gain in a up wind turn.

And look I don't mean to be a jerk about any of this, as I ask dumb questions too, but if you go out and try this and still don't understand that me and Udi and Chuck are right on this then you guys probably do need some good ground schooling. I am certain though that if you go up and try these turns as a experiment and focus hard on watching what happens as your doing it, it will all make sence.

rehler

12-12-2003, 08:11 AM

Udi, you asked: "Ken, explain please why, in your words "the safety issue only applys to loss of lift - the downwind turn" if the same inertia rules apply to upwind and downwind turns?"

I ment: Loss of lift (downwind turn) when you are near the ground is the safety problem. Increase in lift (upwind turn) is not a sefety issue.

But wait! I'm wrong. There would be the same loss of airspeed either way - downwind or upwind turn. I need to think about this more.

rehler

12-12-2003, 09:04 AM

Another thought.

I am convinced that the gyro downwind turn problem is real (physics) and I believe it is more than (in addition to) the visual ground reference problem. I am trying to figure it out like everyone else.

Perhaps the gyro downwind turn loss of lift problem has to do with the rotor acting different than the wing (fixed to the aircraft). The rotor creats lift all around 360 degrees as the rotor is acting like a wing as it turns at every point of the rotation regardless of the direction of air movement. The fixed wing, however only lifts when it is aimed in the forward direction. Also the gyro rotor is different from the powered helicopter rotor. The gyro rotor increases or decreases its speed as needed to keep the gyro at 1 G (the right amount needed to lift the weight).

The fixed wing instantly provides more G force when in a turn. The gyro rotor blade does not react instantly because it has to increase the rotor rpm to increase the G force lift and this takes some time. This is a big difference!

Because of the above difference the inertia of the gyro allows it to continue its original path prior to a turn, while the fixed wing responds instantly to the air placing the G force on the pilot. The gyro will continue to move (skid through the air) in the original direction until the rotor blades speed up to react to the new G force.

During this brief period of time the gyros forward airspeed and lift reduces causing the problem we are discussing.

Does this idea hold water?

Heron

12-12-2003, 09:39 AM

Everyone is jumping from one theme to the other, and now Chuck E. wants to jump from the proverbial band wagon . . .please don't, but if you do don't forget the chute!
Lets get this subject under the scope of downwind/headwind turns and what happens to any situation in a gyro and why?
Please?
Does it sink downwind? Does it do anything headwind?
When a loaded rotor is pushed from the back what is the reaction of the aircraft?Inverted from the front push?
In other words, does the wind pushes a rotor down from the back?
It seems to me that is a combination of speed and AOA that causes the sink.
And for you guys flying at 5 k . . .who cares about a couple dozen lost feet?
Thanks
Heron

Udi

12-12-2003, 10:07 AM

I have a basic problem, Ken, with any argument that claims dissymmetry between downwind and upwind turns.

I believe in the fish-in-a-bowl/fly-in-a-box/butterfly-in-a-car type analogy. I don't see any reason why there should be any dissymmetry between downwind turns and upwind turns. You are flying in a moving body of air. The velocity of the air, and your gyro, relative to the ground is irrelevant.

The only reason for any kind of loss of lift dissymmetry in a turn, in my humble opinion, is when the air itself isn't symmetrical. This could be due to altitude dependent wind gradient or gusts. Otherwise, there is no "wind" in the sky! Take a wind meter with you when you go flying. Can you measure the wind speed (other than your airspeed) while flying? You may be able to measure gusts though…

I thought all this downwind turn stuff was just “flying 101”, but now all of you guys are making me wonder maybe there are some real subtleties in the way unstable air affects a gyroplane. If there are, I would really like to hear a good scientific explanation.

Udi

rehler

12-12-2003, 12:33 PM

Udi,

I agree with you completely with all aircraft I have flown - except for gyrocopters. So, what could possibly be different?

Please read my post up above this one about 3 posts. That's my best guess at this point. But I am convinced that it is real so there must be a "physics" answer to explain it.

As you suggest, however, it does not explain dissymmetry in a turn. But no one complains about loosing altitude in an upwind turn?

pwendell

12-13-2003, 11:01 AM

Maybe I'm just dense, but it seems as if there are so many different threads to this discussion that it is really losing focus.

With respect to the experience of losing altitude during the downwind turn after takeoff, I think the explanation is simple. While climbing after takeoff, we are at full, or nearly full, throttle. When we enter the turn, some of the power -- lift -- that was being used for the climb is now used to make the turn. So, the rate of climb slows or we actually begin to lose altitude. The steeper the turn, the more pronounced this effect will be. If the pilot also unconsciousely confuses apparent groudspeed with airspeed, a phenomenon that Ron has explained so well, and actually reduces power, it can get real dangerous real fast. The lower the gyro's climb rate, due to engine performance, pressure altitude, etc. the more it will tend to loose altitude. This effect may also be further exagerated by the fact that gyros tend to fly very tight patterns and, as a result, make a steeper crosswind/downwind turn sooner after takeoff than most fixed wing aircraft.

I'm still a student gyro pilot who hasn't yet soloed, so what do I know? But that's how it seems to me.

I think it is indisputable that, once aloft, normal wind ceases to be a factor with respect to gyro performance. Sharp gusts and strong gradients are another matter of course.

Phil_Ruffin

12-13-2003, 02:23 PM

opps!

mrford61

12-14-2003, 06:34 PM

I know this topic is nearly done to death but I rally would appreciate an explanation to an incident I witnessed on a very windy day at a "fly in" (only 5 gyros).

A pilot fitted a set of old 22 ft benson blades, aluminium with funny looking slots cut in them, to his gyro instead of his usual 23 ft wide cords. He took off into the strong 20knot ? wind and climbed to about what appeared to be 150-200'. He turned downwind and as he flew back past us you could see he was gradually losing height and doing his best to climb. The motor was running fine. I watched him descend over the tree-line then heard the horrible sound of a gyro hitting the deck. The pilot was completely unscathed, the machine was a wreck. All he said was it just would not maintain height. I am not questioning physics, just curious.

P.S.
Said pilot was feeling very shame until about 3 hours later another pilot clipped the outstretched windsock with his rotor as he passed low so his mate could take a photo. A spectacular crash at high speed with the machine scattering in pieces. That pilot got off lightly with abrasions and 2 broken arms.

P.S.S
Neither pilot flies any more.

GyroRon

12-14-2003, 07:53 PM

How fast did it look like he was flying downwind?

Most all gyros will have to fly about 20 mph to maintain altitude, this is flight ahead of the powercurve. Fly slower and the gyro will be losing altitude. Most gyros the power curve starts even higher. So if he was flying DOWN WIND even at the powercurve at say 20 mph then add the fact that he was in air moving across the ground at 20 knots - which is like 23 or 24 mph - then even flying at the powercurve he would appear to you on the ground to be flying along downwind at 40-44 mph.

While he was flying INTO the wind and climbing he would have been flying faster than the powercurve to be climbing so his airspeed would have had to be let's say 40 mph BUT then the 20 knot wind would have him doing a ground speed of only 20 some odd mph.

So in a nut shell, his observable speed from on lookers on the ground would have been fairly slow up wind and going much faster down wind - Even if he had gone by downwind at or slightly behind his gyros powercurve.

Did it look like he was a good bit faster downwind than upwind? If so was it ALOT faster?

you see my guess would be he climbed out and then turned downwind. Doing this at a fly in, he would most likely be watching the ground - to see who is watching him, We ALL do it at fly ins. Also turning downwind in a 20 knot wind, His ground speed would get Very noticably faster - To you on the ground and him in the pilots seat.

Had he took off, flew upwind and then turned downwind and flew downwind all at the same AIRSPEED - say 45 mph -, he would have had about a 20 mph ground speed upwind and a ground speed of near 70 mph downwind. A BIG difference in ground speed.

All of a sudden picking up all this speed while watching the ground, I think he pulled back stick and slightly reduced power and got behind the powercurve. If you reduce below a certain point in a gyro, pulling back on the stick will NOT make you go up it will only make go fly slower. So he could have pulled back and got slow even with the engine making a lot of noise.

In a gyro you can not stall. But you can get behind the powercurve, and it is a lack of performance. The only recovery from it is to trade altitude for airspeed to get back ahead of the powercurve.

So I think he got behind the powercurve, His engine was running just fine and making plenty of power, But he didn't drop the nose to get the airspeed he needed to get the gyro flying again - He was so low at this point lowering the nose would seem like a BAD thing to do to most pilots, and he basically mushed it in behind the powercurve all the way top the ground.

Had he turned back into the wind, without lowering the nose to gain AIR speed, he would have probably flown backwards or at least appeared to hover in the 20 knot headwind due to the high wind speed and his slow air speed.

The proper recovery for what he did would have been to lower the nose and add power to gain airspeed and get ahead of the powercurve. Due the the increase in ground speed, for safetys sake he should have turned back into the wind so that at least if he was going to crash he would have crashed at a ground speed of nearly zero rather than a ground speed of 20 knots or better.

Hope this make sence. I tried. And it is just my two cents.

PS too bad they both quit gyros. Had they opened their minds some, they might see where it was them not the gyro to fault.