Dubai - WAG - Gyro down 9.12.15

EGNF

Newbie
<<As I mentioned earlier just because Icon has now produced an almost stall proof airplane, does not make every other fixed wing a bad airplane.>>
Actually they have produced a SPIN resistant aircraft, which involved a substantial weight penalty, and required a subsequent weight dispensation from the FAA, who specify BRS as mandatory, it still stalls!
Ivan
 

C. Beaty

Gold Supporter
The methods of eliminating residual moments from gyros have been known for 80 years; they don’t cost anything nor weigh anything.

That these flaws continue to be incorporated is a reflection of the knowledge of the “designers,” who in most cases are members of the cut-n-try school, scaling up Bensens.

Whatever a product may be, from automobiles to whisky and cigarettes, there will always be brand loyalty.
 

Rick E

Newbie
All good points, but maybe it's pushing it to think of an MTO as a barrel. As I mentioned earlier just because Icon has now produced an almost stall proof airplane, does not make every other fixed wing a bad airplane. Knowing ones airplane limits and flying within them is pretty basic even for a neophyte like myself. Vx, Vy, Stall Speed etc. Point being - flown within it's envelope, the MTO and others have proven themselves to be very capable aircraft.
As I said, be great to see you guys get together and produce the perfect touring gyro. Not so smart guys like me will be lining up to buy them............
Off for a breakfast flight with some buds now.
You keep writing what I'm thinking Loftus, Merry Xmas to all regardless of what you fly.
Rick
 

Doug Riley

Platinum Member
Spin-proofing an airplane is a much tougher nut to crack than torque-balancing a gyro. For one thing, stalling an airplane's wing is a normal part of its operation . That's how you land the thing. The very difficult design trick is to allow the stalling of both wings but prevent the stalling of only one at a time.

Torque-rolling (or slip-rolling) a gyro is not a part of anyone's flight routine, as far as I know. Both of these "maneuvers" are uncommanded excursions from controlled flight. Should you wish to roll the gyro, a little or a lot, there are control inputs that will accomplish this for you while you maintain control. In fact, a gyro has quite a lively commanded roll rate.

IOW, the problems of gyros' slip-roll and torque roll don't accurately analogize to FW spins. A more accurate FW analogue to the gyro's torque roll might be the torque-roll problems of very high-powered single-engine prop planes, such as the Gee Bee racer or even the P-51.

Still the analogy isn't perfect. These planes simply had enough torque to overwhelm their ailerons' power, at low airspeeds at least. In the gyro, these instabilities are especially insidious because they are normally masked by rotor thrust, only to jump suddenly out of the closet when G's are reduced.

Moreover, a FW plane can endure very high roll rates with no ill effects on the plane (as long as it's not right next to the ground). That's not true of a gyro whose airframe decides to snap-roll on its own: the rotor can only follow the frame at roll rates of X degrees per second; at (frame-led) roll rates above X, the the rotor lags behind so much that it crashes into the teeter stops and/or starts to stall blades.
 

eddie

RAF, turbo subaru 230hp
doug, thats a very good explanation,of a very deadly problem with gyro's.





Best regards,
 

RotorRambler

Junior Member
doug, thats a very good explanation,of a very deadly problem with gyro's.
I agree, Eddie. Doug Riley is one of the best explainers around.

I'll bet he could explain quantum physics in less than a hundred words and with an analogy no more complicated than popcorn.

Ira
 

eddie

RAF, turbo subaru 230hp
IRA, his explanations make me think that he is more of a pilot than a armchair math guy.

To me his explanations should end a lot of needless arguments!





Best regards,and happy new years
 

chipchap42

Newbie
Spin-proofing an airplane is a much tougher nut to crack than torque-balancing a gyro. For one thing, stalling an airplane's wing is a normal part of its operation . That's how you land the thing. The very difficult design trick is to allow the stalling of both wings but prevent the stalling of only one at a time.

Torque-rolling (or slip-rolling) a gyro is not a part of anyone's flight routine, as far as I know. Both of these "maneuvers" are uncommanded excursions from controlled flight. Should you wish to roll the gyro, a little or a lot, there are control inputs that will accomplish this for you while you maintain control. In fact, a gyro has quite a lively commanded roll rate.

IOW, the problems of gyros' slip-roll and torque roll don't accurately analogize to FW spins. A more accurate FW analogue to the gyro's torque roll might be the torque-roll problems of very high-powered single-engine prop planes, such as the Gee Bee racer or even the P-51.

Still the analogy isn't perfect. These planes simply had enough torque to overwhelm their ailerons' power, at low airspeeds at least. In the gyro, these instabilities are especially insidious because they are normally masked by rotor thrust, only to jump suddenly out of the closet when G's are reduced.

Moreover, a FW plane can endure very high roll rates with no ill effects on the plane (as long as it's not right next to the ground). That's not true of a gyro whose airframe decides to snap-roll on its own: the rotor can only follow the frame at roll rates of X degrees per second; at (frame-led) roll rates above X, the the rotor lags behind so much that it crashes into the teeter stops and/or starts to stall blades.
Doug,

I'm new to this and looking to avoid some potentially fatal mistakes. I appreciate your brief explanation above but I'd like to know more. If I look up Torque roll, I just find a bunch of RC modeler info or stuff that isn't relevant to gyros. Do you know (or anyone else) if there's anything published anywhere that really explains it from the gyro perspective?

As I understand it, the rotor does not produce torque, so the torque must be coming from the engine propellor? And the effect is seen at low rotor rpm?

Thx, Paul.
 

Doug Riley

Platinum Member
Paul: Mainstream aviation considers the gyroplane to be the flying equivalent of a one-horse open sleigh -- fun perhaps, but hopelessly obsolete. So there's been very, very little professional engineering literature about them written since the 1930's.

There's a book by one Brooks (Peter?) about the Cierva gyros (look on Amazon). It recounts the efforts of the inventor of the gyro to eliminate torque roll, once he designed out the wings and ailerons that he'd used on the earlier models. It really tells you all you need to know -- about the nature of the problem and about how to fix it. Very briefly:

Yes, we're talking about the rolling torque that is caused by the reaction between the airframe and the prop.

As long as the rotor is pulling upward on the frame with a large and steady force, it's possible for this upward pull to be aimed a little to one side and thereby cancel the rolling tendency. Problems solved? Not.

Everything's fine until the rotor's upward pull decreases. It can do so either because of strong turbulence or an intentional low-G (an arc toward earth) maneuver by the pilot. The reduction in rotor pull (thrust) then allows the prop's torque to roll the gyro, even though the pilot did not command a roll. The roll can be violent enough in extreme cases to cause a crash; it's happened several times over the years, in many different types of gyro.

Ron Herron, designer of the Little Wing tractor gyro, retraced Cierva's steps as outlined in the old Brooks book, more or less showing the rest of us how it can be done.

We should have figured this out long ago, as the original Bensen gyro with 90 HP engine would lift one wheel during a ground runup, at least if there was no one in the seat. IOW, it tried to pull a torque roll without even being in the air.
 

GyrOZprey

Aussie in Kansas.
Brilliant explanation Doug....

Brilliant explanation Doug....

You just simply & perfectly answered a LOT of my remaining :noidea: :confused: ... I understand the prop-roll effect ... I counter it with a little left stick in my single seater ---every time I break ground! ... but for some reason ...the reason for offset -rotorhead of the new-gen gyros ...eluded me!
You're the BEST!!! :first:
Thanks :yo:


Paul: Mainstream aviation considers the gyroplane to be the flying equivalent of a one-horse open sleigh -- fun perhaps, but hopelessly obsolete. So there's been very, very little professional engineering literature about them written since the 1930's.

There's a book by one Brooks (Peter?) about the Cierva gyros (look on Amazon). It recounts the efforts of the inventor of the gyro to eliminate torque roll, once he designed out the wings and ailerons that he'd used on the earlier models. It really tells you all you need to know -- about the nature of the problem and about how to fix it. Very briefly:

Yes, we're talking about the rolling torque that is caused by the reaction between the airframe and the prop.

As long as the rotor is pulling upward on the frame with a large and steady force, it's possible for this upward pull to be aimed a little to one side and thereby cancel the rolling tendency. Problems solved? Not.

Everything's fine until the rotor's upward pull decreases. It can do so either because of strong turbulence or an intentional low-G (an arc toward earth) maneuver by the pilot. The reduction in rotor pull (thrust) then allows the prop's torque to roll the gyro, even though the pilot did not command a roll. The roll can be violent enough in extreme cases to cause a crash; it's happened several times over the years, in many different types of gyro.

Ron Herron, designer of the Little Wing tractor gyro, retraced Cierva's steps as outlined in the old Brooks book, more or less showing the rest of us how it can be done.

We should have figured this out long ago, as the original Bensen gyro with 90 HP engine would lift one wheel during a ground runup, at least if there was no one in the seat. IOW, it tried to pull a torque roll without even being in the air.
 

fara

AR-1 gyro manufacturer
Propeller Torque effect not Torque roll

Propeller Torque effect not Torque roll

Doug,

I'm new to this and looking to avoid some potentially fatal mistakes. I appreciate your brief explanation above but I'd like to know more. If I look up Torque roll, I just find a bunch of RC modeler info or stuff that isn't relevant to gyros. Do you know (or anyone else) if there's anything published anywhere that really explains it from the gyro perspective?

As I understand it, the rotor does not produce torque, so the torque must be coming from the engine propellor? And the effect is seen at low rotor rpm?

Thx, Paul.
Paul you need to search for
Propeller Torque Effect "not" torque roll.
That will bring you to the right information. Its experienced in any propeller driven aircraft out there. Its a generic aircraft engineering term and is explained for all types of aircraft that use propellers.

When you lift off the ground though and have to use left cyclic, that is not just propeller torque effect (which is indeed a rolling effect), its also P-factor increasing due to change in attitude and also partly gyroscopic precession for the same reason (sudden change in attitude) These create rolling and yawing effects both. You will see you will need "less" left cyclic if you control your attitude change and allow smooth change in attitude to lift off. In essence any change in attitude nose up from level flight (change in AoA to a higher AoA) is accompanied by an increase in p factor and that means also a corresponding increase in yawing tendency that needs to also be countered by the pilot. propeller torque effect remains constant for a given power setting and prop combination. This yawing can also induce a rolling to one side in certain conditions.
 
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Gyro_Kai

Senior Member
And the laws of physics are re-written again.
There are pilots (not good ones), who answer to lift-off with violent attitude changes. However, if you have your noswheel in the air, keep the throttle where it is and wait for the wheels to leave the ground, there is no attitude change other than one wheel and then the other leave the ground.
The attitude change is along the roll axis, because the formally level attitude changes to a slighly side-slanted one, due to the fact that there is a torque working. The frame will lean far enough to create the same counter torque to the frame and then stays in equilibrium.

While on the ground, the forces on the landing gear provide that torque.

Ela and MTO have countered this problem cosmetically, by off-setting the roll-axis joint.

The fun starts when lots of forces changes, i.e. you go sideways for a x-wind landing, still all forces in equlibrium, and then a gust or shear hits you and one of the forces, the rotor-pull, vanishes for a moment. If the propeller torque is countered with an epennage, then there is one less problem to take care off. However, if it is not, and the x-wind comes from the direction, you are already leaning in...whohoo.

Kai.
 
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Vance

Gyroplane CFI
An answer to Paul's question.

An answer to Paul's question.

When you lift off the ground though and have to use left cyclic, that is not just propeller torque effect (which is indeed a rolling effect), its also P-factor increasing due to change in attitude and also partly gyroscopic precession for the same reason (sudden change in attitude) These create rolling and yawing effects both. You will see you will need "less" left cyclic if you control your attitude change and allow smooth change in attitude to lift off. In essence any change in attitude nose up from level flight (change in AoA to a higher AoA) is accompanied by an increase in p factor and that means also a corresponding increase in yawing tendency that needs to also be countered by the pilot. propeller torque effect remains constant for a given power setting and prop combination. This yawing can also induce a rolling to one side in certain conditions.
In my opinion a gyroplane flown well lifts off with very little angle so P factor and gyroscopic precession are not much of a factor on takeoff.

All the gyroplanes I have flown that needed a lot of pedal on takeoff and had power/yaw coupling had short vertical stabilizers and short rudders.

In my experience; any need for cyclic input on climb out is barely noticeable. They are many gyroplane models that I haven’t flown so it may be more evident in them.

In my opinion Paul; the way to avoid challenges with torque roll in most gyroplanes is to keep the rotor loaded or reduce power if it is not.
 
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fara

AR-1 gyro manufacturer
In my opinion a gyroplane flown well lifts off with very little angle so P factor and gyroscopic precession are not much of a factor on takeoff.

All the gyroplanes I have flown that needed a lot of pedal on takeoff and had power/yaw coupling had short vertical stabilizers and short rudders.

In my experience; any need for cyclic input on climb out is barely noticeable. They are many gyroplane models that I haven’t flown so it may be more evident in them.

In my opinion Paul; the way to avoid challenges with torque roll in most gyroplanes is to keep the rotor loaded or reduce power if it is not.
That's correct Vance. That is what I am saying. Abrupt changes in attitude on take-off exacerbates yaw effects. Taking off smoothly reduces them almost to the point of not being noticeable
 

fara

AR-1 gyro manufacturer
Picture sequence of the accident

Picture sequence of the accident

Here is a sequence of photographs from the WAG gyroplane fatal accident. The broken part is to the best of my knowledge is the pilot's unstrapped helmet coming off in a possibly badly executed un-coordinated banked turn.
 

Attachments

C. Beaty

Gold Supporter
In frame 14:33:21, the rotor indicates zero “G”, being flat with respect to the flight path and with no perceptible coning.

The machine then rolls in a direction opposite to propeller rotation.

This is a pretty good example of torqueover.
 

thomasant

Member
Incredible! (numbers from the bottom)

Straight and level frame 14:24:25
Rolled right (?) frame 14:24:26
Upside down frame 14:24:27

As I see it, he rolled in 1 second!
 
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