Understanding VX and VY to Fly safe.

Ghetto Wash

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find an instructor to teach you how to hand spin up your rotors. Dot use a eurotub and pre-rotator to get your training in.
This isn't the first time I've heard someone say that hand spinning rotors will facilitate learning rotor management. It sounds like a wise idea to me. When I start my training, it will be in a "Eurotub". Can rotors be spun up by hand in one, or MUST the prerotator be used in Autogyro/Magni machines?
 

PW_Plack

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So your saying just forget about airspeed the gyro will never sink and I have no change of believing I'm flying faster airspeed even if I horse her off = just let her fly?
"Letting her fly" starting from the proper takeoff attitude and full power is not "horsing her off." If you're going to "horse it off," which usually means jerking the cyclic back before it's ready to fly, you're neither balancing on the mains nor following the numbers in your POH. Not sure how that applies to this conversation.

OK here are my last questions. For an new pilot Without airspeed indicator.

!) How do you confirm your human senses are correct? What instrument do I use instead?
2)AT full power takeoffs.. How do I know I am not behind the power curve? What instrument do I use?
John, for your (1) and (2) above, the only "instrument" needed until you get it off the ground is the observed attitude of the airframe, determined by "reading" the height of the nosewheel off the runway.

If you're trying to execute a short field takeoff, yes, you need the ASI, but not till after the mains are in the air.
 

Texasautogyro

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I find this thread interesting that people will take items out of context to try to prove a point.

Number one.

A student should learn ground rotor handling from day one. This includes balancing on the mains and basically flying the rotor. Once they master that then understanding drag and angle of attack comes into play.

In my introduction to this topic of VX and VY I should have mentioned this.
However I also use the Section from ATP standards to describe problems with lifting off at to slow a speed or to high a speed in reguard to clearing a 50 ft object.
It makes no difference what kind of aircraft you fly a nose high attitude on ground roll increases drag. This will cause you to use more runway. If you are in soft field or rough field it is taught to lift off in ground effect for that purpose. Then leveled to increase to a safe climb out speed meaning VX or VY. But in normal conditions after correct GROUND ROTOR management the lift off speed should be properly controled to lift off as close to correct speed as possible.

If done correctly the nose lifts and this is our indication the rotor has reached enough rpm to fly. You can cross check this with an RPM indicator if needed. The problem then comes into play does the aircraft have enough thrust to maintain altitude? This is where the climb speed comes into play. You can have full lift in the rotor but also have so much drag from angle of attack in the tilt of the blade that you simply cannot fly. Some times lift off does happen and you are behind the powercurve! This is why we cross check with the correct VX or VY.

Another problem i see is climbout with partial power. Again this is a no no! On take of you are either committed or you are not so when proper rotor rpm or the lifting of the nose is achieved you advance throttle to full if take off is desired. None of this climbout at 3/4 or so stuff i sometimes see. Now if you need to abort you abort start over if things do not seem right. Live to see another day. The two basics in every aircraft i have flow are power it altitude. Pitch is airspeed. Of course they work together.

The two gyro crashes in Europe Paul describes are not because of speed at all. They are because they did not teach correct ground rotor management. If they allowed the front wheel to lift indicating the rotor was spun up and then held it just off the runway instead of pushing it to far forward over speeding and slowing the rotor then jerking back instead of aborting. They would have let the gyro lift off just about right.

I have shown many students that there is a sweet spot in almost all gyro models that after balancing they will lift off at almost exactly vx all on there own. Just a simple cross check verifies safe climb proformance. Now as Birdy says I have flown 1700 hrs in gyro and can almost tell what speed I am without looking. But a new student does not. This is the low time danger zone and numbers are needed to fall back on to assure you have what you need when things go south.


I know of at least 15 accidents in the last few years that are related to no ground rotor training. And or not understanding the importance of climbing at VX or VY. You simply just cannot go with a pitch or ATTITUDE angle. This changes with many things like thrust weight and wind. But if you come into land at speed then you know you have a safe approach not matter what the power setting. There are many reasons why you use varied powed setting for the approach depending on conditions. This will effect the pitch of the decent. This is why you just cannot use constant pitch or ATTITUDE for climb or landing because its dynamic. You pitch for speed. A student needs to understand this. The POH is just a basic guide. But if you change the format and design or add things to the aircraft you might as well be a test pilot and throw the POH away.

You will then need a new weight and balance and might need to adjust speeds for what ever you changed.

Just one more note. Years ago the FAA did have an ATP Gyroplane rating I know someone who has it.
 
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All_In

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Good post Desmond.

Yes I read as each person changed my statement to before lift off. As the thread was about Vx and Vy so was clearly asking just after lift off.

I mean it is like they do not know what Vx and Vy are used for!! I've never even thought about Vx or Vy BEFORE lift off. Have you?
Not sure what they are thinking how would Vx or Vy even apply before lift off? You match the numbers after lift off there is no point before or needed in any way that I can see or understand?

But hen Vance and all the others referenced airspeed in there procedures they referenced airspeed and I was happy again.

Didn't learn much form this thread or there answers until the end as I had already learn what they were sharing.

I do understand what you are saying and matches physics to me.

Even my buddy Paul switch it to before lift off. I do not write well is my only guess?
 
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All_In

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Desmon do you have time to instruct still.
I believe my parts are coming in Dec. By Feb she should be ready to fly.

I'd like to schedule some training with you in Feb?
 

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LittleJohn, Clear your pm box.:focus:
Yo Bro... Thank you I made space.


And I'm really looking forward to your fly-in at your Baja house this YEAR!
 

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John- I am not here much, but still enjoy reading stuff from my past life. Looking forward to you doing solo Vx and Vy take offs!
 

Cammie Patch

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A couple of thoughts to stir the pot.

1. Vx and Vy are not constants, in fact at a certain point they are the same. When is this?

2. What exactly is "seat of the pants" flying? It is definable. Someone teach me a short ground lesson on how to fly a "seat of the pants" maneuver, such as a takeoff or approach. I think the attempt will be educating on it's own.

3. And one thing I've been thinking about lately: to what degree is a gyro affected by ground effect? Is it possible that what we think it ground effect, is just the result of leveling off to increase airspeed? Most gyros are hardly a lifting body. I can visualize it easily in a FW, or a helicopter, but the geometry and the mechanics of a gyro make me wonder if it really has the effect we think it does.
 

Texasautogyro

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A couple of thoughts to stir the pot.

1. Vx and Vy are not constants, in fact at a certain point they are the same. When is this?

2. What exactly is "seat of the pants" flying? It is definable. Someone teach me a short ground lesson on how to fly a "seat of the pants" maneuver, such as a takeoff or approach. I think the attempt will be educating on it's own.

3. And one thing I've been thinking about lately: to what degree is a gyro affected by ground effect? Is it possible that what we think it ground effect, is just the result of leveling off to increase airspeed? Most gyros are hardly a lifting body. I can visualize it easily in a FW, or a helicopter, but the geometry and the mechanics of a gyro make me wonder if it really has the effect we think it does.

Yes this is true I tried to explain this somewhat in the first opening post. Introducing VX and VY speeds. In general avation I think they sometimes try to use a safe speeds that actually might be just a bit high for a margin of safety. However looking at this picture might help. These numbers can change based on conditions.
 

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Cammie Patch

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That graph won't be the best one for showing the relationship between Vx and Vy based on altitude, since it only shows on Vx speed and one Vy speed (that graph actually is the one used to determine exactly what value those speeds are. A better graph is one that shows the relationship between Vx and Vy per the full range of attainable altitudes, IOW, I want the Altitude on the vertical axis, and CAS on the horizontal axis.


When flying an Avidyne glass PFD that displays Vx and Vy on the airspeed tape, the pilot will notice that Vy and Vx move closer with an increase in altitude.

Here's another thought: Since these numbers meet at the same value at absolute altitude (IOW, it becomes the only airspeed that will maintain altitude), is it an airframe issue or a power issue?
 

Texasautogyro

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Yes that does show well how they converge.
 

All_In

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John- I am not here much, but still enjoy reading stuff from my past life. Looking forward to you doing solo Vx and Vy take offs!
Thank you Brother!!!

I miss you!

This year will be going to more fly-ins towing my ride(s) so each time I'm anywhere near you I'll be stopping a bugging you.

When I bring the G2sa two place we will go flying.

So glad Barb is on the mend her and your life should be so much better from now on.
 

All_In

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Hi Cammie

OK you get it I would also like to learn from you and fly with you at ROTR!

And maybe we could arrange a side trip like we did last year flying up the Snake river at twin falls in our flight of 3?

If the Air show at Twin Falls the same dates each year Would like to plan and invite those at ROTR to stay go to the airshow and fly of the Snake river with a gallgle of rotorcraft.

Thank you for posting I've learned from that!
 

Vance

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My Opinions about one two and three.

My Opinions about one two and three.

A couple of thoughts to stir the pot.

1. Vx and Vy are not constants, in fact at a certain point they are the same. When is this?

2. What exactly is "seat of the pants" flying? It is definable. Someone teach me a short ground lesson on how to fly a "seat of the pants" maneuver, such as a takeoff or approach. I think the attempt will be educating on it's own.

3. And one thing I've been thinking about lately: to what degree is a gyro affected by ground effect? Is it possible that what we think it ground effect, is just the result of leveling off to increase airspeed? Most gyros are hardly a lifting body. I can visualize it easily in a FW, or a helicopter, but the geometry and the mechanics of a gyro make me wonder if it really has the effect we think it does.
I will try Cammie. It appears I don’t type fast enough as you have already answered question one.

1. VX and Vy are the same at the absolute ceiling because there is no climb; they get closer as the absolute ceiling is approached.

2. I have not tried to teach anyone seat of the pants flying. I feel it is important to learn how to fly well with various flight instruments inoperative. If I had a gyroplane with no flight instruments I would not fly it. My monocular vision and low fear threshold may color my opinion

In the gyroplanes I have flown the angle of the fuselage is a good indication of air speed. Once I have something to line up with the horizon at a particular IAS and power setting I can use that to manage air speed. Power off is particularly consistent.

In my opinion rotor rpm in a gyroplane is primarily important for takeoff. It is not hard to develop a visual perception for the appearance of the rotor rpm. If I can still see the individual blades it is too soon to accelerate.
If I am being too aggressive with acceleration In The Predator it is easy to feel a throbbing begin in the cyclic.
It is not hard to feel when the rotor takes ahold of the air and it is time to advance the throttle. I would not operate out of a short field without a rotor tachometer. Once off the ground rotor rpm appears to take care of itself unless I unload the rotor so I don’t unload the rotor without a rotor tachometer.

The altimeter is already not really accurate enough for landing and as a one eyed pilot I use angles, sight pictures and how one thing moves in comparison to another. If I am trying to get over a mountain; I am high enough if the things behind it are getting taller as I approach and too low if they are getting shorter.

I love my vertical card compass but I don’t miss it much as long as I have a chart. I fly low enough that it is easy to relate things on the chart with what I see to manage my navigation.

I have had my yaw sting disappear and find I get a general feel for yaw by how the wind hits me. I feel it is sloppy flying but close enough to keep me in the air.

I find it more of a challenge in the Cavalon with the doors on and I practiced a lot using the yaw string to validate my efforts.

3. I feel that a gyroplane experiences ground effect and I have validated this by flying level low to the ground while reducing power. In The Predator I can get down to 1,620 engine rpm in level flight when we are less than a foot above the runway and it typically takes a little over 1,940 engine rpm for level flight 20 feet above the runway.
The Cavalon seemed even more affected by ground effect but I didn’t quantify it because I was not comfortable flying that low at 43kts in the Cavalon. Based on how she climbs out I suspect I feel ground effect up to around three feet above the runway.
I haven’t flown any other gyroplane enough to get a feel for ground effect.
Part of how I land The Predator is feeling the ground effect of the horizontal stabilizer when it is time to flair.
 
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All_In

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I will try Cammie.
Good post Bro!
I was reminded and learn from that!!!

Thank you so much!!!!!!!

PS:
I have yet to feel ground effect in a gyroplane but too few hours to be concentrating on looking for it yet.
I did feel the 1st gyroplane,a RAF, and all the others when she flew off. But not ground effect yet. You sure feel ground effect in FW, aircraft, I've flown so far. They all stop descending at the same glide slope and some float!
 
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Vance

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However I could justify the time to fly the black box up and mount it on the Preditor and show you how to use it for your next airshow so we could create a google earth view of the your 'E' Ticket ride and then we could fly?

When is you next airshow Bro??????
The next air show I am planning on flying in is the Cable Air Show in Upland January ninth and tenth John.

More information available here:
http://www.cableairport.com/airfair/
 

All_In

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The next air show I am planning on flying in is the Cable Air Show in Upland January ninth and tenth John.

More information available here:
http://www.cableairport.com/airfair/
Oh that's great.

I can justify taking person time if I'm helping our rotorcraft community at the same time. Really looking forward to training with you.

Let try a week before the airshow.
I'll ship the black box up so you can install it before I come up. Pito tube needs to be in clean air on your ride and Would like to be able to use it a few times and makes sure it works before the airshow. So all of us could fly on Google earth with you!!!

Then when I come up will show you how to charge it, download the flight data log to your computer so your have some experience before the real flight.

Training in the data logger should only take a few hours and as for installing we can talk on the phone as we often do and have it finished and then I can fly with you and fly home when I come up to play.
 
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Cammie Patch

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I think seat of the pants flying is an interesting discussion. I'm going to try to quantify it, at which point it may morph into "flying by the numbers".

What can we use our seats for? I can sense a change in position of a force, or a change in the amount of force. I notice this in a flair while landing, or as pitch changes in some maneuvers. I feel the pressure move from my seat up my back. I like to point this sensation out to my students.

Is "seat of the pants" flying all about what we see? We can see the pitch of the aircraft change, as well as bank. These factors can be assigned numbers, as in pitch angle and bank angle.

Does what we see give us the info needed to fly a safe airspeed? Not around the edges, since we can only sense airspeed by our motion relative the ground and the wind will have a great effect on this. One could argue that we can sense airspeed by sound, and I do think this is true to a point, and if one gets to know their aircraft well enough it may have more of an impact than is obvious. ANR headsets can mask this.

Any other sensation we feel while flying has been proven to be untrustworthy, as demonstrated by many pilots who have flown into the clouds without trusting their instruments.

So, my argument here would be that good flying is this: Pitch + Power = Performance, although this is complicated in the take off phase by the changing speed of the rotors. But in pretty much all other phases I would stand by this formula. How is performance defined? By airspeed or climb/descent rate. IOW, airspeed and/or climb (or descent) rate is directly obtained by a combination of an engine RPM (or MP) setting combined with the pitch of the aircraft.

So, those CFIs who teach flying "by the seat of your pants", would you ever advocate flying certain phases of flight without using a certain power setting? Would you teach in a aircraft that didn't have a tachometer? That is because that number is such an important element in the formula. I'm sure you also teach a sight picture, which is the pitch of the aircraft, and the other element in the formula.

TL;DR, I don't think that the two different techniques in teaching are really all that different, and a good instructor will teach a student what power settings to use and what pitch attitude to look for. The most important part is that the student is able to replicate the performance when needed.
 

Cammie Patch

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Hi Cammie

OK you get it I would also like to learn from you and fly with you at ROTR!

And maybe we could arrange a side trip like we did last year flying up the Snake river at twin falls in our flight of 3?

If the Air show at Twin Falls the same dates each year Would like to plan and invite those at ROTR to stay go to the airshow and fly of the Snake river with a gallgle of rotorcraft.

Thank you for posting I've learned from that!
Hi John, hopefully TWF will have their airshow again next year. Would be great to do another run up the falls!
 
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