Fatal in France

Pim,

We live in America. We do not want our government interfering any more than they absolutely have to. WE have several freedoms we want to keep.

Air bags and such is not wanted. I want to fly what I want to, and I alone am responsible for my outcomes. I do try to be safe. I just don't want to be ordered to do so.
 
Trade-offs!

Trade-offs!

Sounds like the MTO vs Magni choice ...decision is a trade-off ..... sporty nimble flying characteristics .....( but must KNOW & STAY with-in the envelope) vs. the solid slower -response "safer" - original "Euro-gyro" design!

John Nagle's ( Monarchist) recent excellent review of his piloting experiences doing a comparison between the two Euro-gyro makes validates my limited impressions of the differences between the two - from a pilot's perspective!

http://www.rotaryforum.com/forum/showthread.php?t=39371
 
I believe vance is saying in a nice way that PIM is a Troll,anyway he sounds that way to

me, at the least he has demonstrated that he has no personal knowledge of ever flying

a gyro, or perhaps any thing at all.


Best regards,eddie.....
 
Thank you for the link to the video Arnaud.

Thank you for the link to the video Arnaud.

Ferran,
I don't know about Ela, but I can tell you that Magni is safe enough to perform a "bell" (cloche) trajectory, providing you chop power at the top of the climb, before starting down : see at 1:09 in this video
https://www.youtube.com/watch?feature=player_embedded&v=x4EYJ40hTss

As I watch this video I tried to understand what the pilot is demonstrating.

In the open tandem gyroplane I fly (The Predator) I use the rudder in an effort to maintain coordinated flight.

The Magnis I have flown required more rudder work than The Predator. Even with my limited experience with the Magni I was able to maintain a semblance of coordinated flight and she seemed to fly much more efficiently in coordinated flight.

This pilot in this video appears to make no effort to maintain coordinated flight, airspeed or altitude during the maneuvers.

What is the pilot demonstrating?

I never saw the indicated air speed drop below 40 kilometers per hour, is this considered slow flight in a Magni?

Is this the proper speed at the top of the “Bell”?

Why is it important to chop the power at the top of the climb when performing a “Bell”?

Is the “Bell” what you would describe as a low G event?

Apparently you have a lot more freedom about how you fly in France.

In the USA this pilot could be violated for performing these maneuvers with a passenger.

In The USA this pilot could be violated for performing these maneuvers below 1,500 feet above ground level unless in waivered air space (during an air show).

Thank you, Vance
 
We have a continued Divergence of opinion Jordon.

We have a continued Divergence of opinion Jordon.

Vance I agree with what you are saying only that it the change in the rotor thrust vector (RTV) is the trigger for the PPO. A HTL gyro is always flying with the thrust line above the CoG and the pilot uses the RTV and the tail to keep it from pushing over.

I think PPO occurs when the the RTV is reduced and to do that requires unloading the rotor, which is done by reducing g, Whether that is low g I don't know but it is reducing the RTV sets the gyro rolling.

However flying in a slip is generally done at a lower airspeed and that the tail is not aligned with the relative wind so it may not be effective and can't be relied upon to arrest the forward rotation caused by the drag + HTL that is occurring.

I bet when ELAs are side slipped they produce a lot of drag and the drag vector is applied several inches below the CoG, they are also HTL and the propellor thrust line is several inches above the CoG adding to the moment in the same direction.

Because of the gyro is in a slip the tail will not be aligned with the relative wind. Furthermore the configuration of the tail (tri-tail) where the vertical stabilisers would disturb any air that was going the tail would make it a lot less effective or even ineffective.

So the pilot is now balancing the Propeller thrust vector and the drag thrust vector with the RTV with little help from the tail. In essence the gyro becomes a HTL machine with no tail.

If the pilot unloads the rotor (reduce gs) for whatever reason then it can PPO (drag vector + propeller thrust exceeds the RTV counterbalance thrust).

I believe the large horizontal tail on the ELA, MTOs etc all but eliminate the threat of PPO because it is the main counterbalance to the drag and propeller thrust vectors as long as there reasonable airspeed and the tail is aligned with the relative airflow , however there are flight regimes that make the tail less effective or even ineffective, slips being the main one, and then you are flying a HTL gyro with no counterbalancing force other than the RTV.

These gyros are PPO proof so as long as you keep the tail flying. Just saying this to make people think, the tail is critical on these gyros you need to keep it loaded just like the rotor.

I too are not an instructor just putting an opinion out there.

Cheer, Jordan

How do you use the tail to prevent a power push over in your MTO Jordon?

The MTOs I have flown had the horizontal stabilizer set at close to zero angle of attack in normal flight.

Is yours set up differently?

I feel any change in equilibrium can be the trigger for a power push over in a high thrust line gyroplane.

In my opinion for the description of how the rotor thrust vector affects equilibrium; it needs to be described in relation to something.

In my opinion unloading the rotor in a low G maneuver does not necessarily change the rotor thrust vector in relation to anything

I feel a power push over involves a forward tumble.

I feel that a slip generally speaking does not initiate a forward tumble and it is more likely to involve a roll.

I feel any high thrust line gyroplane is not “PPO proof”.

I feel these are important principles in gyroplane flight and understanding them is important to flying a gyroplane safely; otherwise I would just let it go by.

Thank you, Vance
 
Ok, Jal. I agree with your last message. However these things cannot be understood as black and white.

I totally agree that the factor which triggers all the problems is a 0 g or very low g situation.

It is true that the ELA is a very slight HTL gyrocopter. Magni is a slight HTL too, but it is more HTL than ELA. Both have a very similar HS which provides a neat negative lift push down in the tail in flight.

If you fly an Ela and with the aircraft perfectly trimmed you add power and let the stick free, the gyro will pitch its nose up. However it will pitch up too much and the final trimmed speed will be clearly lower than the initial airspeed.

In a Magni, in the same situation, the result will be smaller nose up pitch, which will keep the final airspeed closer to the initial one. We can say that Magni is better tunned than Ela…

However the important thing is what the reason is? I think that it is because the propeller blow into the tail generates an additional negative lift which Magni compensates with a higher HTL than Ela.

Be aware: more power implies more tail negative lift, that is to say, more nose up. It is the tail the main responsible for compensating the HTL, not the rotor.

Ferran

A divergence of opinion.

In my opinion there are many things that trigger problems flying a gyroplane besides a zero or low G situation.

I have never measured the thrust line offset of a Magni or ELA at gross weight.

I felt it might be more than “slightly high”.

How high is the Magni thrust line compared to the center of gravity at gross weight?

How high is the ELA thrust line compared to the center of gravity at gross weight?

In both the Magnis and the MTOs I have flown when I added power the nose dropped and when I reduced power the nose pitched up. I noticed this more at low speeds than high speeds.

There was also a noticeable yaw with a power change in both. The yaw was more pronounced in the MTO.

Am I doing something wrong?

I have not flown an ELA.

Thank you, Vance
 
It's possible for a symmetrical H-stab that normally flies at zero AOA to prevent a PPO, if it has a fast enough airflow and is large enough. It will do so a bit inelegantly.

The aircraft must progress far enough into the (impending) PPO for the H-stab to acquire a negative angle of attack. That is, the gyro must nose down, probably by 5-10 degrees. At that point, the H-stab will "bite" and will be creating a significant down-force on the tail. We hope that this force is not only enough to cancel the tail-up force created by prop thrust, but also enough to decelerate and reverse the pitching-over momentum that the fuselage has already developed.

I haven't had the chance to explore the flight behavior of a typical Eurogyro in detail. I'm told, however, that at least the Magni M-16 will, in fact, pitch down a bit before stabilizing, if the rotor is unloaded. It won't PPO; it will dip its nose. That's what you'd expect.

A HTL gyro with an immersed H-stab and correct negative incidence, OTOH, won't dip its nose when the rotor is unloaded. On the contrary, the nose will rise. A LTL gyro will do the same.

A H-stab with large tip fins can apparently lose much of its stabilizing power in a hard slip, since the fins cause disorganized flow over the top of the stab and disrupt its lift production. We've heard of scattered experiences with this problem.

Whether PPO was in any way involved in this accident can't be determined without more information than has appeared here. We don't know the throttle setting (engine sound) leading up to the crash, nor do we know the gyro's stance at the time it began to fall (Did it roll over? Which way? Was it slipping? Which way? Did it tumble forward?)

You normally carry a very low throttle setting on approach, so PPO seldom happens at that time in a flight. Drag-over, OTOH, depends only on airspeed and not at all on throttle setting. If someone opens the throttle aggressively on final, for a go-around or to stretch a glide, then PPO and torque-over again become possibilities. Knowing the behavior of the body of the gyro would allow us to rule one or more of these possibilities in or out.
 
Vance

How would you describe this demonstration.

WIATRAKOWIEC XENON - DISPLAY - YouTube

That looked like a very nice gyroplane show routine to me Mark.

He appeared to have good altitude control in tight turns although it is hard to tell without seeing the instruments.

I could see he was using the rudders but without seeing the yaw string I don’t know if he was trying to coordinate the turns.

His rotor speed management appears good and it looked like the rotor was always loaded.

The engine off landing and the turn to the crowd was a very nice finale.

I fly higher when I fly an airshow because I have a low fear threshold and don’t have much faith in the stability of the air near the ground.

I feel there is no way to compare this to the Magni video because it is from a different perspective and missing the yaw string..

I feel we have strayed too far off the topic and if we are going to get into judging air show performances we should do it in a different thread.

Thank you, Vance
 
That looked like a very nice gyroplane show routine to me Mark...

...I feel we have strayed too far off the topic and if we are going to get into judging air show performances we should do it in a different thread.

Thank you, Vance

Thank You Vance for your response and observations.

I didn't intend to stray as far off topic as one might think. My point was going to be that at the top of the climb at full power, full rudder deflection followed by a dive is very near the drag over scenario we are discussing.

Near but, NOT the same (when executed properly.)

(In a helicopter, what he is doing might be called a pedal turn.)

If you are also holding rear opposite stick to stay slow or over a certain point, bad things may be about to happen if continued unchecked.

The design has some to do with the outcome too. (I would not try this in a small or no HS, or short coupled machine like an RAF .)

Gyro's will safely do some amazing things, so long as you keep them within their flight envelope (and also within the pilots experience and skill envelope).

M
 
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....
The design has some to do with the outcome too. I would not try this in a small or no HS, or short coupled machine like an RAF .
...

The Zen gyroplanes have a big HS in the middle of the slip stream.

It balances the prop wash and prop roll torque.

It is also on a very long arm.

It balances the pitch torques.
 
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Pim,

We live in America. We do not want our government interfering any more than they absolutely have to. WE have several freedoms we want to keep.

Air bags and such is not wanted. I want to fly what I want to, and I alone am responsible for my outcomes. I do try to be safe. I just don't want to be ordered to do so.

Spot on. Don't rely on anybody with your own safety but yourself.
 
Ok, Jal. I agree with your last message. However these things cannot be understood as black and white.

I totally agree that the factor which triggers all the problems is a 0 g or very low g situation.

It is true that the ELA is a very slight HTL gyrocopter. Magni is a slight HTL too, but it is more HTL than ELA. Both have a very similar HS which provides a neat negative lift push down in the tail in flight.

If you fly an Ela and with the aircraft perfectly trimmed you add power and let the stick free, the gyro will pitch its nose up. However it will pitch up too much and the final trimmed speed will be clearly lower than the initial airspeed.

In a Magni, in the same situation, the result will be smaller nose up pitch, which will keep the final airspeed closer to the initial one. We can say that Magni is better tunned than Ela…

However the important thing is what the reason is? I think that it is because the propeller blow into the tail generates an additional negative lift which Magni compensates with a higher HTL than Ela.

Be aware: more power implies more tail negative lift, that is to say, more nose up. It is the tail the main responsible for compensating the HTL, not the rotor.

And this is special for Arnaud:

If you drop your power out in Magni in the top of this stupid and dangerous maneuver that you are defending you will be reducing your tail nose up tendency originated by the HS. Of course, this will be totally compensated by the absence of HTL (no power no trust).

I have seen the film and I don’t see any abnormal bell shape maneuver. The rate at which the Magni is lowering the nose is comfortably slow. I cannot say the same about the string: the pilot seems unable of flying correctly coordinated. So I think it would be of much more benefit to him to take some turn classes with a competent gyro instructor that showing us his poor flying abilities.

The case is that this kind of bell shaped maneuver is against the teetering rotors flight nature and must be avoided. There are other much more secure ways to down a too high nose than just pushing naively the stick forward (for example turning hard and letting the nose drop in the turn: you will be lowering the nose at a safe g load factor).

Ferran

Ferran I also agree with what you are saying.

However most slip maneuvers are done as a way to steepen an approach and therefore the engine thrust is low so the tail is not getting a great blast of air from the prop. Instead the stabilizers are blocking the airflow which is coming from the side in a aggressive slip so the gyro is now HTL without the counterbalance of the tail.

The reason why I use drag over instead of PPO, which technically it what I think it should be referred to, is that it is the increased drag vector due to the increased surface area of the pod exposed to the slipstream is the main force of rotation and not engine thrust and therefore is the "power" in PPO, although I am sure even at low rpms the propeller is still providing some residual thrust and being HTL will add something to this moment force.

I have no idea where the drag vector acts, but it obvious to me that it i is below the CoG, and the further below CoG it is applied then has the additional benefit of leverage


Vance not sure of the incidence of the tail on my MTO. Chuck has already explained how the tail works on these machines. The tail work as a dampener that corrects the nose down pitching moment without pilot input as long as there is sufficient airspeed. Also a large proportion of the tail is within the prop blast. The yaw you experience in the MTO is normal, it is designed with the middle vertical stabilser with offset incidence so that it compensates for propeller thrust at cruise power setting, so when you reduce power below 3000 rpm you get a noticeable yaw that needs to be corrected with rudder. It was designed so you didn't need to hold rudder in cruise.

If the tail is in disturbed air it will not produce the aerodynamic force it was designed. I am just speculating but I suspect it is the vertical stabilizers that are disturbing the airflow if the gyro is an aggressive slip and the tail is stalled. If the tail is stalled the you are flying a pure HTL gyro and the only counterbalance force is the RTV. This would make the gyro susceptible to both PPO (drag over) and PIO.

There are many fixed wing aeroplanes where spins are prohibited for a similar reason. That in a spin the airframe disturbs the air flow over the elevator which becomes stalled and the pilot cannot then lower the nose to reduce the AoA of the wing to unstall the aircraft. It the same thing with aggressive slips in gyro with a tri-tail and large cabin/pod, the disturbed airflow stalls the HS and therefore the pilot only has the RTV to balance the drag and thrust vectors, a quick reduction in RTV for whatever reason may result in the gyro tumbling if the drag and propeller thrust forces are strong enough.
Cheers Jordan
 
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Vance,
I have not flown a MT but I have flown a Magni M-16, and it will nose up if you add power. This is not a question of opinions, is a fact. Besides, any gyro which pitches down the nose when adding power it is an unstable gyro. The Ela pitch its nose up. I guess that the MT would do the same thing. I’m totally sure that they don’t pitch down when you add power, Vance. I’m not going to discuss about if they are slight HTL or not: they are stable gyros because when you add power they pitch its nose up. Their HS is working perfectly compensating the HTL (overcompensating in the Ela’s case).

I have talked about this question because is a big misconception to think that shutting down power in the top of a bell shaped maneuver you will avoid PPO. In the Magni’s case this is uneventful. In the Ela’s, it is worse to pull back the power because is overcompensating and it will nose down too much (which is not very good if you are in a low g situation). Probably it is not a coincidence that all these accidents in short final has happen with the power at idle..

My opinion is totally divergent from yours. I’m going to put the things in this way: It is impossible to have a drag over if there is not a concurrent low g situation. This is a fact too, at least if we are talking about Ela’s. And this is the case in this thread. I’m an Ela pilot with a lot of experience in this aircraft and I can ensure you that it will not drag over in a normal 1 g flight situation.

Of course it can drag over in a very low g flight condition. If you want to discuss what is the cause of the control loss in this case you can. However my point is that all sustained 0 g situations conduct to a total loss of control. I know that you don’t believe that is possible to have sustained 0 g situations in a gyro. My answer to that is that more than half a second is a sustained 0 g situation, and unfortunately It is possible to have 0 g situations lasting enough to conduct to accidents.

JAL, I’m not talking about PPO. I’m talking about a 0g event that produces a loss of control. No 0g implies no loss of control: nothing happens.

It is very simple: every gyro control problem starts with a very low g situation.

Any way I understand your point about the forces acting on the pod that can trigger the drag over. However the control authority of the rotor will able to counteract this effect, except in too low g situations.
I agree with you and Chuck when you say that the HS is ineffective in a heavy side slip. However I totally disagree with the concept that in that case you will be flying a pure HTL.

The HS is still in its place under the effect of the propeller blow, Sir. Your explanation about the way in which the HS gives stability is nice. However there is an additional factor: our HS (Magni, Ela or MT) are providing a true negative lift, which compensates the HTL. That means that if you have power in a side slip you are not in the same situation than a HTL without HS. If you drop all the power to idle, then there is not HTL (no power no thrust).

You are flying MT’s. Please do the following test: at a secure flying altitude at cruise speed trim the gyro and don’t act on the stick. Then low the power to 3500 rpm and look what happens. Then come back your first power setting and you will get initial flying condition: cruising speed at leveled flight. Now add more power, say something like 5200 rpm.

I guess than in the first case your gyro will pitch its nose down (and in the second it will pitch up). This is important, because it dictates what you should never do to recover a low situation: reduce power.

These are my two points: 0 g is the main cause of control loss and we have to use the power in the opposite way that everybody thinks to recover very low G situations in these kind of machines.


Ferran
 
Vance,
I have not flown a MT but I have flown a Magni M-16, and it will nose up if you add power. This is not a question of opinions, is a fact. Besides, any gyro which pitches down the nose when adding power it is an unstable gyro. The Ela pitch its nose up. I guess that the MT would do the same thing. I’m totally sure that they don’t pitch down when you add power, Vance. I’m not going to discuss about if they are slight HTL or not: they are stable gyros because when you add power they pitch its nose up. Their HS is working perfectly compensating the HTL (overcompensating in the Ela’s case).

I have talked about this question because is a big misconception to think that shutting down power in the top of a bell shaped maneuver you will avoid PPO. In the Magni’s case this is uneventful. In the Ela’s, it is worse to pull back the power because is overcompensating and it will nose down too much (which is not very good if you are in a low g situation). Probably it is not a coincidence that all these accidents in short final has happen with the power at idle..

My opinion is totally divergent from yours. I’m going to put the things in this way: It is impossible to have a drag over if there is not a concurrent low g situation. This is a fact too, at least if we are talking about Ela’s. And this is the case in this thread. I’m an Ela pilot with a lot of experience in this aircraft and I can ensure you that it will not drag over in a normal 1 g flight situation.

Of course it can drag over in a very low g flight condition. If you want to discuss what is the cause of the control loss in this case you can. However my point is that all sustained 0 g situations conduct to a total loss of control. I know that you don’t believe that is possible to have sustained 0 g situations in a gyro. My answer to that is that more than half a second is a sustained 0 g situation, and unfortunately It is possible to have 0 g situations lasting enough to conduct to accidents.

JAL, I’m not talking about PPO. I’m talking about a 0g event that produces a loss of control. No 0g implies no loss of control: nothing happens.

It is very simple: every gyro control problem starts with a very low g situation.

Any way I understand your point about the forces acting on the pod that can trigger the drag over. However the control authority of the rotor will able to counteract this effect, except in too low g situations.
I agree with you and Chuck when you say that the HS is ineffective in a heavy side slip. However I totally disagree with the concept that in that case you will be flying a pure HTL.

The HS is still in its place under the effect of the propeller blow, Sir. Your explanation about the way in which the HS gives stability is nice. However there is an additional factor: our HS (Magni, Ela or MT) are providing a true negative lift, which compensates the HTL. That means that if you have power in a side slip you are not in the same situation than a HTL without HS. If you drop all the power to idle, then there is not HTL (no power no thrust).

You are flying MT’s. Please do the following test: at a secure flying altitude at cruise speed trim the gyro and don’t act on the stick. Then low the power to 3500 rpm and look what happens. Then come back your first power setting and you will get initial flying condition: cruising speed at leveled flight. Now add more power, say something like 5200 rpm.

I guess than in the first case your gyro will pitch its nose down (and in the second it will pitch up). This is important, because it dictates what you should never do to recover a low situation: reduce power.

These are my two points: 0 g is the main cause of control loss and we have to use the power in the opposite way that everybody thinks to recover very low G situations in these kind of machines.

Ferran
 
You are flying MT’s. Please do the following test: at a secure flying altitude at cruise speed trim the gyro and don’t act on the stick. Then low the power to 3500 rpm and look what happens. Then come back your first power setting and you will get initial flying condition: cruising speed at leveled flight. Now add more power, say something like 5200 rpm.

I guess than in the first case your gyro will pitch its nose down (and in the second it will pitch up). This is important, because it dictates what you should never do to recover a low situation: reduce power.

Ferran

Hi Ferran,
Did you not notice that something more is happening (regarding to those two gyros you are referring above) that not only they pitch the nose up by adding power and/or pitching down by reducing power?
 
Yes, Giorgos. They are yawing a lot if you don't counter act with the pedals, and at very much lower intensityt they roll a little. However, these effects are not relevant to the discussion.

Ferran
 
The late BJ Schramm’s (Rotorway and Helicycle) admonition; “Don’t look at the design, look at the designer” is a profound statement that is unfortunately meaningless to the general public. “If it’s pretty, it must be good” is the usual attitude.

ELA and MTO gyros are copies of a Magni with minor variation of detail. Mr. Magni was a mechanic with no training as an engineer who learned gyro design by building a Bensen.

Is the Aviomania Genesis the only professional design from the eastern side of the Atlantic?
 
Yes, Giorgos. They are yawing a lot if you don't counter act with the pedals, and at very much lower intensityt they roll a little. However, these effects are not relevant to the discussion.

Ferran

I quote this (even if these effects are not relevant to the discussion.) I have not read all the posts but....
This ( much lower roll intensity) is strong enough to roll a gyro upside down in less than a fraction of a second and if you fly with blades unloaded. (Zero Gs, for examble.)
There are plenty of videos on youtube, and I know also gyro pilots with much experience who were eye witness to such kind of accidents. I know only one who survived from this. Just before crashing down the gyro touched ground right side up. The pilot could not say if it was he or his angel who saved him the last second.
Have a nice weekend, Ferran, and all others.
 
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Is the Aviomania Genesis the only professional design from the eastern side of the Atlantic?[/QUOTE said:
I think I have enough experience regarding Genesis, C. Beaty, and I can say YES, that's the only gyro I have flown until now without any tendencies of yow/roll/b.overs. or anything else by adding or subtracting power. Even from very low throttle to full 120 HP turbo engine torques, pilots need not to correct anything. Both gyros, single and tandem, react the same way. They correct themselves.
I don't say this because I am flying Genesis, it's a fact.
 
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