Testing gyros for buntovers potential

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What is the real cause of 99% of these crashes?

How would we attack it?

Thank you, Vance
Vance-----two words come to mine------"PILOT ERROR"----Not a put down to those who died---( I may well be next )-but we all make mistakes----call me at 281-489-2019 anytime---you seem fairly normal!!!------PS Anyone can afford a gyro but find training is as much or more expensive than the machine(and much more difficult to get)-Add to this people look upon them as a toy and add to this some fixed wingers think they are capable of flying one and you end up with bodies---Even after all the lessons and one flys well the God syndrome enters the picture and we get carried away with the power--more bodies---throw in bad judgment and you could fill a grave yard---BUT IT IS FUN!!! LC
 

magilla

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An experimental aircraft is not a car, nor an ATV. If you can't understand that basic premise, then none of us on this forum can help you.

True, a thermodynamics degree won't help you when the engine quits, and an aeronautical degree won't help you once you start to fall from a bunt-over, but in both cases, the knowledge would have helped to prevent either occurrence.

Jvitable, you are free to believe whatever you want about flying, but please don't ruin an excellent thread on testing gyroplane dynamic stability based on your naive and limited understanding of aviation.

You don't need to be rocket scientist to fly a gyro - many here have proven that... but don't poo-poo a thread that is attempting to make us all more educated because you are either intimidated by the knowledge or don't understand it.

Spencer
 

Vance

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Vance-----two words come to mine------"PILOT ERROR"----Not a put down to those who died---( I may well be next )-but we all make mistakes----call me at 281-489-2019 anytime---you seem fairly normal!!!------PS Anyone can afford a gyro but find training is as much or more expensive than the machine(and much more difficult to get)-Add to this people look upon them as a toy and add to this some fixed wingers think they are capable of flying one and you end up with bodies---Even after all the lessons and one flys well the God syndrome enters the picture and we get carried away with the power--more bodies---throw in bad judgment and you could fill a grave yard---BUT IT IS FUN!!! LC
Why are some aircraft designs over represented in fatal accidents if it is 99% pilot error?

Does a particular design encourage pilot error?

Does a particular design have less tolerance for pilot error?

For me, having some understanding of how to stay out of trouble encourages me to participate in gyroplane aviation. I feel that someone that clings to ignorance to overcome their fear may not be well suited to aviation as a hobby and is not likely to produce the growth in our sport that you desire.

I make mistakes and I hope that the way my gyroplane is designed will help me to manage the results of my errors. It is nice to have a way to quantify the tendency to have a power push over. I like not finding out the hard way that my aircraft needs work.

Thank you, Vance
 
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Feel alittle superior do you----

Feel alittle superior do you----

An experimental aircraft is not a car, nor an ATV. If you can't understand that basic premise, then none of us on this forum can help you.

True, a thermodynamics degree won't help you when the engine quits, and an aeronautical degree won't help you once you start to fall from a bunt-over, but in both cases, the knowledge would have helped to prevent either occurrence.

Jvitable, you are free to believe whatever you want about flying, but please don't ruin an excellent thread on testing gyroplane dynamic stability based on your naive and limited understanding of aviation.

You don't need to be rocket scientist to fly a gyro - many here have proven that... but don't poo-poo a thread that is attempting to make us all more educated because you are either intimidated by the knowledge or don't understand it.

Spencer
Spencer-you have a very condescending way about you.I knew enough about gyro theory to get my ticket add-on--You go from basic premise to the most detailed aeronautical analysis of the inner workings of gyroplane flight.I think your comment about me being naive and having a limited understanding of aviation is a very dumb thing for a person in your position to say.You know as well as I that anyone interested in becoming a gyro pilot would be confused and disheartened by this indepth stuff.Your group wants to be test pilots but have never studied the previous crash cases---thats stupid and naive---When I suggest a close look at the root causes I get zip because it does not fall into the groups agenda!!! PS-my engine quit and I am still here-lucky I guess-----Test all you want but please not over my house-----LC
 

barnstorm2

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The reason people get scared off from gyros is our high accident rate. "Gyrocopters" are almost synonymous with "widow-maker" among older pilots.

The reason we have a high accident rate is because so many pilots and passengers have died in PPOs.

Remove the PPOs and we have a pretty good safety record.

We have PPOs because over that past 20 years we have had many machines sold that have design flaws.

The "Pilot Error" is not understanding how and why PPOs happen and how susceptible your machine is to PPOs and if it has the known flaws that lead many pilots into PPOing.

We know that MANY high time pilots and CFIs have died from PPOs so training while it may partially mitigate the problem does not solve the problem or even reduce it to reasonable levels.

We do know that a properly designed gyro can not PPO (CLT) or will be very difficult to PPO (Stable).

This thread describes a fantastic way to rationally and scientifically test your machine for these flaws and tendencies.

Therefore, this thread and methodology is DIRECTLY related to helping our sport and saving lives.

.
 
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Ok

Ok

The reason people get scared off from gyros is our high accident rate. "Gyrocopters" are almost synonymous with "widow-maker" among older pilots.

The reason we have a high accident rate is because so many pilots and passengers have died in PPOs.

Remove the PPOs and we have a pretty good safety record.

We have PPOs because over that past 20 years we have had many machines sold that have design flaws.

The "Pilot Error" is not understanding how and why PPOs happen and how susceptible your machine is to PPOs and if it has the known flaws that lead many pilots into PPOing.

We know that MANY high time pilots and CFIs have died from PPOs so training while it may partially mitigate the problem does not solve the problem or even reduce it to reasonable levels.

We do know that a properly designed gyro can not PPO (CLT) or will be very difficult to PPO (Stable).

This thread describes a fantastic way to rationally and scientifically test your machine for these flaws and tendencies.

Therefore, this thread and methodology is DIRECTLY related to helping our sport and saving lives.

.
Bstormer-remove the ground and you will have a very good safety record-da
 

All_In

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I know I’m going to regret getting involved in this!
Buuuuuuuuuuut, being a newbie I have a perspective experienced gyro pilots and forum members probably don’t.

My hobby is actually learning, so threads like this are very helpful to gyro engineering wantabee’s like me.

However I have observed that even my closes friends and family members eyes glaze over when I try and share or discuss theory with them on any subject like this. Most newbie’s probably are paying much more attention to the squabble unfortunately than the substance of this thread.

As to scarring newbie’s out of the sport, can it get any worst?

Perhaps my current experience will shed some light on the question. All the FW pilot and my friends I have told about entering your sport have all told me, without exception so far, that “You’re going to kill yourself”. So I believe the evidence thus far has demonstrated that the general public even pilots are already convinced the sport is lethal.

Hard to imagine that if they have gotten this far that anything said here so far is really going to keep them out of the sky.

I really soaked up the information on which Gyro you consider as stable and made a note.

Now can anyone make a list of the gyros that are not stable, although maybe we better stick to list the ones you consider stable as this might start another even bigger battle, when you name someone’s favorite?

Cheers be happy,
John
 

C. Beaty

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All_In

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Here are a couple of articles you might find interesting. The first is a synopsis of research performed at the University of Glasgow on the subject of gyroplane stability. The second is an article by French aerospace engineer Jean Fourcade, based at least partially on research conducted at the University of Glasgow.

http://www-legacy.aero.gla.ac.uk/Research/Fd/Project5.htm

http://www.asra.org.au/L_Stability.htm
Oh those links look promising espically the 2nd, now reading…
Thanks,
John
 

mceagle

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jvitable said:
Your group wants to be test pilots but have never studied the previous crash cases---thats stupid and naive
Joe, I think you will find exactly the opposite. Those with the most interest in gyroplane technical safety are also those that have studied accident causation the most. What would be stupid and naive is for us to consider that we know it all and there is no more to learn.
I do not believe that anyone is trying to force you (or any low hour pilots) to do their own stability testing.
Make no mistake, there can be absolutely no doubt that the more knowledge a pilot has of gyroplane aerodynamics and handling, the better and safer pilot he will be. If it wasn't for people like the Chucks and Greg G, you would still be flying basic Bensen's with the ever reliable McCulloch engine.
 
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Really

Really

Joe, I think you will find exactly the opposite. Those with the most interest in gyroplane technical safety are also those that have studied accident causation the most. What would be stupid and naive is for us to consider that we know it all and there is no more to learn.
I do not believe that anyone is trying to force you (or any low hour pilots) to do their own stability testing.
Make no mistake, there can be absolutely no doubt that the more knowledge a pilot has of gyroplane aerodynamics and handling, the better and safer pilot he will be. If it wasn't for people like the Chucks and Greg G, you would still be flying basic Bensen's with the ever reliable McCulloch engine.
Tim-I don't remember seeing a Chuckbird gyro or a Gregtax engine before-sorry!---If you disected these crashes it would give prospective gyro pilots a chance to see these machines are not falling out of the air on their own accord with no warning.But then that would not fit in with C e's agenda.I believe in clt-great-lets make gyros as safe as possible and as forgiving as possible but to be constantly negative about our sport is not the way to move forward.Thrashing CFI's is another problem!Testing is great but making this sport seem so complicated to beginners with all the heavy aeronautical talk just adds to their fears. Our main goal is to eliminate PPO just as designers of fixed wing wanted to eliminate stalls. They finally did--they called the new craft a gyro----I am still getting calls from beginners or want-a-bes that are obviously intiminated by the direction of the forum.The Public dislikes us and we dislike each other--at least we are consistant! LC
 

ckurz7000

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A bit of background (skip if already familiar) ...

A bit of background (skip if already familiar) ...

Just for the sake of some lurkers or newbies getting a bit behind the aerodynamics flung around in this thread:

There is static stability and dynamic stability. A nice mental image of a statically stable situation is a ball sitting in a bowl like the picture below.

Stable.gif

If you give the ball a bit of a nudge to either side, it will respond by returning to its original position. Now, if you were to turn the bowl upside down you'd have yourself an unstable situation:

Unstable.gif

Here, the ball is precariously balanced ontop of the bowl and any slight nudge will make it roll into the setting sun, i.e., it won't return to its original position by itself.

Returning to the original example of static stability, you'll agree with me that after the nudge the ball will roll around a bit inside the bowl until it gradually comes to rest at its original position. This is what in aerodynamic-speak is so eloquently termed a "phugoid oscillation". The picture of the ball in bowl is an example of static stability (because the ball wants to return to its original position after the nudge) as well as dynamic stability (because the rolling around in the bowl after the nudge dies down after a while and the ball comes to rest at its original position).

In the next picture I have tried to separate static and dynamic stability by adding my hand to it, which jiggles the bowl back and forth.

Stable, driven.gif

I had to add my hand to the picture because I wanted to create a situation that has the potential to be statically stable but dynamically unstable. Just imagine that I jiggle the bowl too much and the ball eventually jumps out of it and rolls toward the setting sun. Even though the ball always wanted to roll toward the bottom if left to its own devices, the jiggling motion makes it roll around more and more until it eventually jumps out of the bowl: statically stable, yet dynamically unstable ("divergent phugoid oscillations" is the proper term to drop at your next cocktail party).

The problem -- or shall we say "challenge" -- we face with our gyros is that the shape of the bowl is determined by a lot of parameters and even changes under different flight characteristics. You might have a deep narrow bowl (high static stability) when flying slowly with little engine power. Going really fast, however, your bowl might look more like a flat skillet. In the former, your well trained aeronautical engineer will be speaking of a "high static stability margin", whereas the skillet presents a situation of almost "neutral static stability".

So how are we to determine the shape of our flying stability bowl? One way is by looking at how vehemently the gyro wants to return to its originally trimmed attitude. This is like assessing the shape of the bowl by looking at the force with which the ball wants to roll down its sides: steep bowl -- strong returning force, shallow bowl -- weak returning force. Assessing this restoring force in actual flying conditions is not an easy task for a number of reasons I don't want to go into. But there is an easier way...

You can look at the dynamic stability to learn somthing about static stability. In other words, you can look at how much the ball rolls around in the bowl to learn how deep the bowl is. This is what Greg is suggesting. The good news is that if the ball rolls around at all, you can be sure that you're still holding the bowl right side up as can be seen in the picture below.

Unstable, driven.gif

Here, it becomes clear that with negative static stability (inverted bowl) you can't get the ball to roll around at all. The precondition, therefore, to observe "phugoid oscillations" (i.e., the ball rolling around) in your gyro is to have positive static pitch stability.

I hope that helps, -- Chris.
 

birdy

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when I fly a gyro I am a God!
Like i said justin...... idiot. :) :)

Does a particular design encourage pilot error
Unfortunatly Vance, their first decision was they greatest error, just not their last.
 

b.charlton

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I can trim my RAF to fly hands off for extended periods in nil to mild turulence up to 70mph, over 70 the oscillations become larger and over 80 more divergent, i find it difficult to fly over 80mph for more than 30sec without touching the controls whereas at 60-70mph i can fly all day using only power and rudder. In strong turbulence pucker factor prevents me from letting go of the stick anyway, no matter what the speed. My machine has had a stab on for the last 8 years.
 

chuter

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jvitable:
I am still getting calls from beginners or want-a-bes that are obviously intiminated by the direction of the forum.
Well, they've made their first mistake. God help 'em if they're calling you for advice.

Newbies, look over this guy's past posts; you'll see he doesn't have much to add, just complains a lot.
 

gyrogreg

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Thank you, Chuck

Thank you, Chuck

Chuck, I don't know where you get the patience! For as many years as I have been in this sport, you have been working tirelessly (and absorbing abuses) to try to improve the safey of this sport! I don't know how you keep doing this - year after year! Thank you Chuck. I wish we could really know how many lives you have certainly saved over all these years. I guess some people are jut not savable.

But, sometimes our toughest tasks are to undo the damage others seemingly just want to do! (Trying to convince people that knowledge doesn't matter!?!?) I hope you keep hanging in there! Thanks again!

Also, Chuck, thanks for your last "bowl" post. You have a way to describe these things that I really envy!

I started this thread to try to improve our collective knowledge about these things, and to help individuals be able to make better decisions what and how they fly. I don't intend that these investigations identify just two classes of gyroplanes - safe and unsafe! It is likely even the gyro with the worst accident history has safe areas of their flight envelope! It is the knowledge of what the safe operating range really is on that model that is really important! Exceeding this safe operating envelope is what kills people. We all have to know what that safe operating range is for each aircraft we fly! We are just suggesting a way to determine this safe operating envelope without having to discover it in the few seconds before we die!

What we don't know we don't know is what kills us! If people stray into areas they don't even know exist, they are going to get into trouble one day! But, for the more stubborn among us, the challenge seems to be helping them even accept such important truths as such "knowledge is safety".

I started this thread for two reasons:

1) To expand our overall knowledge

2) To help people grow their knowledge - at least better know what they don't know!

I am sorry that there are attempts to hijack this thread to try to convince people that knowledge is not important. For #2 above, we are just trying to help people make better decisions about what and how to fly. I'm sure most people following this thread can recognize this value. It is those few people however that the hijacker just might influence to ignore valuable knowldege that I do worry about!

- Greg Gremminger
 

gyrogreg

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I can trim my RAF to fly hands off for extended periods in nil to mild turulence up to 70mph, over 70 the oscillations become larger and over 80 more divergent, i find it difficult to fly over 80mph for more than 30sec without touching the controls whereas at 60-70mph i can fly all day using only power and rudder. In strong turbulence pucker factor prevents me from letting go of the stick anyway, no matter what the speed. My machine has had a stab on for the last 8 years.
Ahh, real feedback! Thank you Barry. This somewhat echoes what Jerry Tiahrt first reported on his stock RAF 2000.

But, this report is for a Stick Free condition. A stick free condition can actually be somewhat forgiving! The best way to fly a gyro when it is in an unstable situation is to allow the stick to move. This somewhat prevents actual airframe movement from coupling into the rotor. When the rotor is forced to move in the divergent direction - as a result of the spindle moving with the airframe - fixed stick - the rotor (wing) further agravates the unstable situation by again changing the rotor AOA or loading which again forces the airframe to pitch further in the wrong direction!

The best way to fly a gyro when it is statically unstable is to allow the stick to move where it wants to move - restricting stick movement makes unstable airframe movements worse! The pilot that is proficient at flying an unstable gyro actually learns to move the stick to prevent any divergent motions of the airframe from coupling into the rotor. The worst situation when a gyro is statically unstable is when the pilot restricts the stick even more - or worse yet, reacts to misleading airframe pitch motions with the wrong stick input!

But, on most gyros, such as on your RAF, there is friction and the trim spring arragement that probably makes "stick free" very similar to "fixed stick". We know that when you release the stick in an RAF flying in turbulence, the stick can be observed to move around - this is at least preventing some of the airframe movement from coupling to the rotor! So, your stick free condition is probably very similar to, but likely a bit better than fixed stick. We propose fixed stick just to be sure the stick is not allowed to move at all - which makes the static instabilty more apparent. This also better simulates what a novice pilot might do on the stick - freeze it, or move it wrongly!

When a gyro is flying in the statically stable condition, the airframe movements are in the correct or restoring direction. In this case two beneficial things happen:

1) The airframe movements, from the pilot restricting the stick, or from friction or trim spring coupling these restoring movements back into the rotor, causes the rotor to respond in the restoring, or statically stable direction. A statically stable gyro flies more stably when the stick is fixed! Just the opposite of a gyro in an unstable condition.

2) The airframe moves (pitches) in the proper direction to indicate actual flight path or rotor load condition. This means that if the pilot responds to the pitch movement of the airframe (seat and nose movement), that response will be in the correct, restoring direction. For a gyro in a statically unstable condition, the airframe often pitches in the wrong direction, and the pilot is likely to be excited to exasperate this condition with wrong direction stick movement! In the statically stable case, the airframe coupling to the rotor mostly compensates the disturbance, the airframe barely pitches in the disturbance, and the pilot isn't even necessarily excited into a response - less likelihood of being excited into an over corrective response! A statically stable gyro flies even moe stably in teh fixed stick mode!

Anyway Barry, thanks for the raref eedback. This is good feedback for an RAF with a HS! I certainly hope we might get some fixed stick flight test feedback on this variant - and on other models too! But, if you are not comfortable with fixed stick, please don't do it! Or, at least approach it in small steps!

Thanks, Greg
 

Steve Osborne

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Chuck does not have any problem dishing it out Greg. If you go back and read the majority of CB posts you will see that he has hi-jacked 90% of the RAF threads regardless of content. Welcome to the world of daily abuse and bashing.:)
 
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