Testing gyros for buntovers potential

gyrogreg

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The thread ”Future of Gyros” prompts me to start this discussion on flight testing of gyros. An ASTM Task Team is working on some refinements to the stability portion of the standard. In this investigation, I believe a major light bulb has gone off – at least for me.

People worry most about getting into PIO or a buntover (PPO in terms of a HTL). One intent of the ASTM standard was to provide a way to easily determine by flight test if any particular gyro would be susceptible to buntover or PIO. A simple flight test, performed and reported on many gyro configurations, could be most informative. As you have all probably read, our ASTM standard focused on the static G-Load stability (actually this is the AOA static stability) of a gyro. The static G-Load stability flight test, a banking constant airspeed turn, was intended to be the test that could say whether a gyro could buntover or not. The presumption was that there was a symmetry from the +G-Load condition of a banking turn to the -G-Load condition of a buntover. A buntover is really an AOA static instability that causes a decreasing G-Load to continue and accelerate in a worsening reducing G-Load – nose down pitching.

It turns out that the banking turn flight test really only works for some severely AOA unstable gyros – such as an old-style Air Command with no HS. For less severe AOA unstable gyros, and especially for gyros with strong offset gimbal trim spring arrangements, this test did not define a buntover susceptible gyro very well. In fact, the revealing fact was when Jerry Tiahrt reported that his RAF 2000 passed the static G-Load test and nearly passed the static Power stability test! So, back to the drawing board we went!!! Apparently, the Static Stability flight tests were not truly definitive – by that I mean we know the RAF 2000 is capable of a buntover, and yet Jerry’s static flight testing did not identify it as such. The major problem with the G-Load test is that the offset gimbal provides the overwhelming aft stick pressure in a banking turn – whether the gyro is AOA stable or not. This test works for a FW airplane, but not for a gimbaled gyro rotorhead!

There may be different technical opinions on this, but what I think we discovered with Jerry’s testing is a new, “back door” way to determine if (or when) a gyro is statically AOA unstable and therefore capable of a buntover! The Static Stability tests are important, but they do not provide a definitive indication of buntover susceptibility, or not. What Jerry noted was that in performing the Fixed Stick static flight testing in his RAF 2000, he found that above a certain airspeed, the gyro responded to moderate turbulence with divergent pitch and airspeed oscillations. This got Jerry’s attention! This is an indication of DYNAMIC INSTABILITY. Jerry reported this was disquieting, and he subsequently lowered his personal Vne for this aircraft. (Jerry, if you are listening, please correct anything I might be relating differently than you reported – I did not go back and research our emails and your postings recently.)

I believe this has pointed us to a new determination of actual static AOA instability – ability to buntover. Please try to follow this: If an aircraft is able to oscillate in pitch, whether convergent, divergent or constant amplitude oscillations, it must be statically AOA stable. The mere fact that it demonstrates Phugoid pitch oscillations (slow rate, constant AOA oscillations), that gyro has static AOA stability. If it was statically AOA unstable, it could not oscillate – it would simply diverge exponentially nose-up or nose-down (buntover)! A phugoid oscillation occurs because there is static AOA stability – it is the small AOA divergences from steady state that provide the negative feedback restoring moment that causes the gyro to oscillate rather than statically diverge.

Fixed Stick flight testing was the key! With a fixed stick, you are evaluating the pure aircraft response and the airframe pitching, whether in the restoring or divergent direction. With a fixed stick, the airframe pitch response to a disturbance couples directly to the rotor (wing) and causes the whole gyro to react. If the airframe pitching response is in the unstable direction, the aircraft is statically AOA unstable. The key is that it is the Fixed Stick condition that really reveals the ability to oscillate in turbulence or if disturbed by a pilot input. This is actually the standard DYNAMIC fixed stick flight test that has always been part of the gyroplane ASTM standard – and that Jerry inadvertently flight tested when his gyro developed diverging oscillations in moderate turbulence!.

What I think we have discovered is that most gyros, such as the RAF 2000, at moderate airspeeds near their Minimum Power Required Speed (MPRS), are statically AOA stable and will exhibit slow rate phugoid pitch oscillations. The existence of oscillations indicate the AOA static stability! However, as in the case of the RAF, some gyros might become statically AOA unstable at higher airspeeds (airframe aerodynamic nose-down moments) and at higher power levels – both of which are moving the “effective” RTV forward of the CG – to the Chuck B. “classic” definition of AOA unstable and able to buntover!

If a gyro approaches static AOA instability (with a worsening power/airspeed condition), the static restoring AOA pitch moment becomes weaker and weaker. As it does so, the phugoid dynamic oscillations become less convergent, neutral, and eventually divergent oscillations. The standard requires that a gyro not be dynamically unstable – in other words, still able to oscillate, but with diminishing oscillations. But, even if the dynamic phugoid oscillations become neutral or divergent, they are still oscillations, and there is still static AOA stability – however weakening! If we require a gyro to be dynamically stable – excited phugoid oscillations eventually diminish to zero - that gyro still has a margin of static AOA stability – it is assuredly statically AOA stable and cannot buntover in that flight (power and airspeed) condition!

So, then how do we test for the ability or not for a gyro to buntover? We conduct the standard Fixed Stick Dynamic Test. The key to this is that the stick must be truly mechanically fixed. It is not good enough to just try to hold the stick steady! An experienced pilot just cannot avoid stabilizing inputs! With the stick fixed, fly at MPRS in afternoon turbulence to observe that the pitch oscillations that are excited do not start getting worse and worse – divergent dynamic response – dynamically unstable and weak static AOA stability. (This test can also be done in calm air with a pilot “step” input on the stick – like professionals do it – but just flying in turbulence will work for informal testing just as well!) Then, increase the Fixed Stick airspeed by about 5 mph – change the fixed position of the stick - and watch for divergent oscillations in moderate turbulence again! Keep increasing airspeed and power to see if there is any airspeed where the pitch oscillations start getting worse and you, the pilot, release the fixed stick to stabilize the oscillations. This is the point, beyond which, that gyro will have meager AOA static stability, or beyond which it will be actually statically AOA unstable and able to buntover! That determines the flight condition (power and airspeed) beyond which that gyro can buntover or PPO. That should identify your Vne condition. Gyros that are capable of bunting over will only do so at statically unstable combinations of power and airspeed – normally at higher airspeed because airframe aerodynamic moments are normally statically destabilizing! This flight testing will determine your “safe operating flight area”. A really good thing to know – especially since buntovers are so insidiously surprising otherwise!

This test should be conducted at higher airspeeds with lower power settings as well – the prop thrust moment or lack of moment can contribute to AOA instability on certain configurations!

This Phugoid dynamic stability test is simple and safe to be conducted by any gyro pilot that is proficient in flying that particular gyro in moderate (afternoon thermal) turbulence conditions. The second post below will describe two ways to safely “fix the stick” for this testing. Jerry Tiahrt helped develop the “chain” or rope method. This is how he identified the buntover susceptible flight conditions for his RAF 2000.

I would appreciate any comments or flight testing feedback on these concepts. I have been evaluating these concepts for some time, and I think it is time to start sharing all this with others to hopefully provide some flight test feedback and validation. I have become convinced that this simple flight test will truly indicate if or when a gyro can buntover (or PPO). But what about PIO? To pass this test, a gyro must have a dynamic damper – a HS! It turns out that a HS, besides providing static stability directly, actually provides dynamic damping that also extends the static AOA stable margins and range. The dynamic damper is also the mechanism that prevents rapid PIO pitch oscillations (the rapid, constant airspeed, varying AOA oscillations) that promote PIO. I don’t have complete theoretical reasoning for this, but it can be expected that any gyro that is shown to be buntover proof from the above testing, will also be highly resistant to PIO due to its strong dynamic damping..

There are many aspects of the above theory that I haven’t discussed here – such as susceptibility to buntover in a push over the top of a zoom! But, the above are the basics. I hope some of you will provide some flight testing – and I hope this flight testing really opens some eyes – as it did for Jerry Tiahrt!

If you do some testing, please share your results.

- Greg Gremminger
 
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gyrogreg

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How to ”Fix the Stick”

How to ”Fix the Stick”

The “Fixed Stick” testing must be done with a truly mechanically fixed stick – it is not good enough to just hold the stick as still as you can! Both of these methods of “fixing the stick” lend themselves to quick release for pilot recovery from uncomfortable flight conditions. Both of these methods allow for lateral stick movements for roll control while fixing the stick in pitch:

Method 1 – Chain: A small chain attached to a secure point forward of the cyclic, with an electrical conduit clamp on the cyclic, works well. Route the small chain through the conduit clamp hole and hold it in your hand on the cyclic. Be sure that releasing the chain releases the restriction on the cyclic. To conduct the test, fly at the test airspeed, pull the slack out of the chain through the hole and grip the chain under your hand. Then, pull aft enough to hold the chain tight throughout the test. Adjust the length of the chain to fly at different airspeeds. (You can use a braided nylon rope in place of the chain if you assure taht the rope cannot stretch and the knows will not allow the length to tretch under tension - a small cahin from a hardware store may be better!)

Method 2 – “Jam Stick”: Fashion an adjustable stick or several stick lengths to jam between the cyclic stick and a solid point forward of the stick – instrument panel! Adjust the length of the stick for different airspeeds. Hold the forward pressure on the “jam stick” to hold it into position against the stick. I coated the rounded tips of the stick with a bit of rubber to help hold it in place, while still allowing some amount of lateral movement for roll control. To regain full control, simply relax forward pressure on the stick to let the “jam stick” fall out.

See photos attached. Both of these methods require that the solid point forward of teh stick be truly solid - if the instrument panel can flex, I fashioned a metal bracket attach point to temporarily stabilze the attach point.

- Greg Gremminger
 

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C. Beaty

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The chain and conduit clamp will cull out the egregious stability offenders but the mildly unstable machines will slip through as a result of control flexibility. Particularly if trim springs are located at the rotorhead, allowing control backlash to play a role.

But good enough for home testing. It is important the chain be as pictured, made from sheet metal stampings and not the kind with twisted wire links that can snag and hang up.

Any meaningful stability testing for certification purposes must provide a breakaway lock at the rotorhead.
 
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donshoebridge

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“safe operating flight area” = SOFA, a nice compfy place to be.

Greg,

Are you going to update your testing documents for everyone to download?
 

gyrogreg

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“safe operating flight area” = SOFA, a nice compfy place to be.

Greg,

Are you going to update your testing documents for everyone to download?
Don,

Eventually, I hope to provide such guidance - detailed PRA articles. But, I would prefer to vet these ideas deeper, and it would be nice to get more correlating flight test feedback on this concept.

The ultimate validation for any theory is to correlate flight test data with real world history - in this case of buntover history. I fully expect that gyros that indicate buntover susceptibility per the dynamic stability flight test, within their published operating area, would also be those that have a history of buntovers and PIO.

Having been slightly stung by the lack of correlating flight test reports on the Static Stability flight testing recommendations, I would prefer a bit more flight feedback from a wider range of gyro models. (It took a couple years before we got any data from an RAF - Jerry Tiahrt's reports - to identify an issue with this guidance!) I would prefer to get flight test correlating feedback before making any declarations based on pure theory!

One problem, I suspect, with getting flight test feedback is that perhaps when someone's favorite configuration actually identifies problems per the flight tests, they are not so willing to admit that. Jerry's report on his RAF 2000 was one of the few reports we have ever received – thanks Jerry, you may have done the whole sport a real service! I think it is important to at least get some flight test feedback for the more common and popular gyro models – not just Magni, SH and RAF – specifically confirming that phugoid pitch oscillations are damped – dynamically stable – or not! I’m confident that all of the buntover free gyros will demonstrate dynamic stability throughout their published operating area. I am confident that gyros that do have buntover histories will have areas of their published flight envelope where they are not dynamically stable!

I do intend soon to distribute our proposed ASTM standard changes - which includes test method suggestions for this Dynamic Stability criteria as well. I will be distributing this to manufacturers and old ASTM gyroplane committee members, and others who might provide valuable comments and flight test reports.

But, this particular Dynamic Stability flight test is simple. Here it is in more words than you probably want!:

- Prepare and install one of the suggested methods to "fix the stick"

- Fly in the middle of a sunny day where there are thermals you can feel in the gyro - thermals you regularly have flown in!

- Start at a comfortable airspeed - MPRS (45-55 mph?)

- Set the stick position, using the chain or "jam stick" for that airspeed

- Let the gyro ride the thermals and verify the pitch disturbances do not just get worse and worse. - use lateral stick movement to keep the gyro level, but keep pressure on the chain or "jam stick" to maintain that stick pitch position. (Do not lean or sway your body to try to steady the aircraft!!!! - experienced pilots might do this naturally!)

- Repeat this test for 5 mph higher airspeed - set the new stick position.

- Repeat at 5 mph incrementally increased airspeeds.

- When pitch oscillations start getting worse instead of steadying out on their own, stop the test - beyond this airspeed/power point that gyro will likely be susceptible to buntovers! This is your Vne - at least for that power condition!

- Strictly speaking, this test should be done at all combinations of power and airspeeds. So, for all the higher airspeeds, the test should be done at normal power, idle power and full power - allow the gyro to climb or glide with the different power settings.
Typically, stability issues arise at higher airspeeds! But, they may be more prominent with higher power or with lower power (at high airspeeds), depending on prop thrustline configuration. You don’t really need to worry about or measure the prop thrustline, just test the gyro at higher and higher airspeeds for both high power and low power!

One caveat: If the fixed stick positions do not result in a steady airspeed, that gyro has a more basic problem – Static Airspeed Instability. All aircraft should have a specific airspeed that results from a specific stick position. This airspeed may be different at different power settings, but airspeed should at least be steady at any particular fixed stick position. If, when the stick is fixed, the airspeed keeps getting faster and faster, or slower and slower – never settles out – then that gyro has other issues and will definitely have controllability issues.

- Thanks, Greg Gremminger


- Greg
 

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test pilots

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Yikes!
Good luck guys -- I hope you get some useful data without incident.
Personally, I won't be caught above 0 kts IAS and/or 0 ft AGL without the "full, free, and correct" motion of all controls that's been on every checklist I've ever used. I just can't get past the cringing that comes from even hearing the term "jam stick".
 

Not Yet

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Either one of these devices can be instantly disabled to allow full movement of the stick. What is the problem?
 

Resasi

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The often thankless and unremarked upon test flying regime often does call for doing procedures that a lot of pilots would not consider doing.

That someone is prepared to look into the areas where we should not be for the benefit of all of us is a time for us to be very grateful. In this particular instance it does seem to be safe enough.
 

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I'm with Waspair...

I've only thing I fly is the R22, and other than a ride in a gyro, I can't speak to them. But I can't imagine rigging MY stick to no back cyclic even with a quick release. Bad things can happen pretty fast. Maybe a good CFI that is used to fixing problems that students have created. IMHO mortal pilots like myself shouldn't be messing with 'jambing sticks.

Tom
 

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I'm thinkin' (always dangerous!) that those that are concerned about the safety of these tests aren't visualizing how the test is conducted.

In the method of using the adjustable stick, 'Jamming' doesn't mean wedged as normally thought of. In this case it only means held in place by the controlling hand where it can't move. Quit holding it in place and the device disengages (drops from position) instantly; well it will as long as we have gravity!

I can't think of, but may be wrong, any scenario where an emergency would cause the test pilot to want or have to push the stick forward. In fact, in a gyro, this reaction is kinda a no, no anyhow!

I see the chain method as possibly being a little more problematic but if designed right where there is no possibility of the chain/string getting snagged then it appears safe also.

I do think that the 'stick' method might be better from the stand point that unconscious movement of the cyclic would be easier with the chain/string.

Mr. Beaty has mentioned several times how difficult it is for a pilot to conduct fixed stick tests (no devices used) because of learned responses to outside forces. Unless the pilot is extremely well calibrated, it is unlikely that he/she will be aware of subtle inputs. Thus the need for 'training wheel' type of devices that doesn't require a calibrated pilot.

I'm would think that eventually these test methods would evolve to include ways to quantify or document the results. It would appear to me that manufacturers in particular could benefit from this.

But 1st things 1st; the tests need to be performed by several pilots and their data reported. The data reported would include any problems in conducting the tests using these devices/methods.


Edit to add: It suddenly dawned on me that the 'stick' method might not work too well in an open frame gyro! "Whoops, didn't mean to bonk you on the head Farmer Brown!" Sticks are cheap but head bonks might not be! Haven't thought this thru this long enough to suggest a restraint that doesn't present problems of its own.
 
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magilla

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I'll test 'em! This is what I love about being a test pilot.

Ooooops, gotta get my gyro rating add-on first, then I will be more than glad.

Seriously, these tests, if conducted properly in a regimented fashion should prove no more dangerous than regular maneuvers.

The tests that get me on edge are checking max performance of the engine, operating for minutes at a time at max throttle/performance.

Fixed stick flight control checks shouldn't be a problem if you plan the maneuver, practice it dead stick (to include simulated emergencies) then go execute in a controlled environment (traffic pattern).

Good Luck,

And great work, Greg! Thanks for the update.

PS, I did not read into this thread ANY negativity about RAF2000s. The argument was well presented and well explained, and I cannot see anyone finding bias or fault with the test as described.
 
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C. Beaty

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What’s the big deal? Both Dick DeGraw and his wife Carroll have been flying gyros with stick locks for years. Admittedly, spring detent locks.

Paul Bruty in Australia flew his RAF-2000 with the telescoping stick lock and found he had to drop it after the first excursion from trim. That’s been several years ago.

Roger Wood in Cincinnati Flew his Bensen with a stick lock back in the 70s and learned he had to take over after about 3 cycles of oscillation.

There is simply no other way of determining dynamic stability of a gyro due to the masking effect of the offset gimbal rotorhead without expensive instrumentation.

At least one helicopter had a spring detent stick lock, the Hiller Hornet. There was a heel button the floor to engage/disengage it.
 

Chuck_Ellsworth

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The tests that get me on edge are checking max performance of the engine, operating for minutes at a time at max throttle/performance.

.
That also used to make me nervous and it took a while to get used to it when I first started doing unlimited aerobatics in the Pitts S2B.....but we just set full RPM and full throttle and lock it there during the whole routine.....amazing how they hold together. :plane:
 

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The only thing that comes to mind is - what if the jam stick dropped out and got stuck in the control mechanism or rudder assembly somehow and the pilot was not able to reach it?? We lost a fellow here in an ultralight a few years ago for that very reason. The stick would have to be secured from 'dropping' in advance of the test in my opinion (unless someone has a third hand). Am I missing something here??
 

gyrogreg

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The only thing that comes to mind is - what if the jam stick dropped out and got stuck in the control mechanism or rudder assembly somehow and the pilot was not able to reach it?? We lost a fellow here in an ultralight a few years ago for that very reason. The stick would have to be secured from 'dropping' in advance of the test in my opinion (unless someone has a third hand). Am I missing something here??
Tie a line on it or tie one end loosely to the instriment panel. - Greg
 

gyrogreg

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Yikes!
Good luck guys -- I hope you get some useful data without incident.
Personally, I won't be caught above 0 kts IAS and/or 0 ft AGL without the "full, free, and correct" motion of all controls that's been on every checklist I've ever used. I just can't get past the cringing that comes from even hearing the term "jam stick".
If a gyro requires such constant attention on the stick, you already have your answer! That gyro is statically unstable, like constantly having to work at balancing a yard stick upright in the palm of your hand. Stable gyroplanes and aircraft do not require constant attention on the stick! A stable gyro will fly indefinitely at a near constant airpseed with a fixed stick - even in turbulence! The stick fixed position should determine a constant mean airspeed - determined by power and stick position. Any deviation from that attitude or airspeed should tend to immediately correct for that deviation! That is because a stable aircraft has a restoring pitch moment when there is any deviation from steady state pitch and airspeed - the definition of static stability.

A stable gyro requires much less attention to the stick than a helicopter - a helicopter, without stability augmentation is basically statically unstable* - but this does not need to apply to gyroplanes. The examples Chuck quotes above, where the locked stick must be immediately released, are perfect examples of dynamically iunstable unstable gyros, and they can very likely buntover if pushed a little harder with the right disturbance and an inattentive pilot! - fixed stick or not! If they actually still oscillate before the pilot has to take over, with just a little more power or airspeed, that gyro will be statically unstable and primed to buntover!

A well stabilized gyro requires much less attention to the stick than similarly sized airplanes in the same turbulence. This is partly because the rotor is less sensitive to wind deviations. But it is also because the stable gyro forces immediate restoring cyclic into the rotor - and the rotor very powerfully starts restoring the steady state. This is one of the most remarkable features of a stable gyroplane, one that astonishes every doubting Thomas airplane pilot until they actually experience it themselves. That is one of the most fun things to demonstrate to FW pilots in a gyro - find the most turbulence you can find and have THEM fly in it! I have sold a few gyros (Magnis) to FW pilots for just that reason!

It might be difficult to design a gyro that would not have phugoid oscillations, and therefore be AOA statically stable, at MPRS or less. That's why I say to start at that airspeed - then increase airspeed in small increments. At the point where oscillations start growing instead of settling out, you do still have static AOA stability - you are still safe from buntover, but stop there and don't go any higher airspeed because you are losing your static stability safety margin.

Thanks, Greg

* Ironically, a helicopter with an effective HS on the long tail moment arm - lots of dynamic and static stability - becomes more and more AOA and airspeed statically stable at higher airspeeds. That alone should be enough hint about what to do with gyros. Where do you think the thrustline is on a helicopter? It is at the rotor level - very HTL! And yet, they can fly stable at higher airspeeds if they employ a good HS. And, a helicopter in those conditions, also does not require a lot of constant attention to the stick. (Cobra and Apache pilots have lots more things to do than to just fly the helicopter.) In all aircraft types, the only attention the joystick should require is for the pilot to command a deviation from the steady state condition.

- Now is about the time someone complains that the stable gyro won't be any fun then! It will be a "lead sled"! Come on, where are you? Speak up! Let's see if you know the difference between a fixed wing and a non-fixed wing! Anyone want to explain the difference as it relates to maneuverability and controllability?
 

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... -use lateral stick movement to keep the gyro level, but keep pressure on the chain or "jam stick" to maintain that stick pitch position...

Either a stick or a chain will cause any movement of the stick in the roll axis to create a change in stick pitch position, since the locks will hold the stick in an arc, not in a straight lateral line. Is this significant?
 

gyrogreg

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... -use lateral stick movement to keep the gyro level, but keep pressure on the chain or "jam stick" to maintain that stick pitch position...

Either a stick or a chain will cause any movement of the stick in the roll axis to create a change in stick pitch position, since the locks will hold the stick in an arc, not in a straight lateral line. Is this significant?
Paul, Not really! The gyro is still flying without pilot stabilizing pitch inputs. It would be very difficult for the pilot to learn how to put in stabilizing pitch inputs with this lateral stick action only. In moderate turbulence, once it is level at the power and trimmed (stick position) airspeed, there are norrmally not a lot of lateral inputs required anyway.

If you really wanted to be precise with the "jam stick", you could square the base of the "jam stick" - against the flat instrument panel, so lateral movements on the corner of the stick would compensate the pitch input! Do the geometry. But, this is not necessary. Just do it the simple way - it will be very revealing! The difference between a well stabilized gyro and a gyro that starts losing its dynamic stability is very convincing! Remember, at the power/airspeed point where it starts losing its dynamic stability, it is still oscillating and therefore still AOA statically stable - and incapable of a buntover at that apoint. But, don't press beyond that loss of dynamic stability point! You found your Vne!

- Greg
 

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* Ironically, a helicopter with an effective HS on the long tail moment arm - lots of dynamic and static stability - becomes more and more AOA and airspeed statically stable at higher airspeeds. That alone should be enough hint about what to do with gyros. Where do you think the thrustline is on a helicopter? It is at the rotor level - very HTL! And yet, they can fly stable at higher airspeeds if they employ a good HS. And, a helicopter in those conditions, also does not require a lot of constant attention to the stick. (Cobra and Apache pilots have lots more things to do than to just fly the helicopter.) In all aircraft types, the only attention the joystick should require is for the pilot to command a deviation from the steady state condition.

A helicopter rotor, like a propeller produces a line of thrust, not thrust applied to a point.

The thrust produced by a helicopter rotor acts in a straight line that is very nearly coincident with the tip plane axis. The horizontal component of the forward tilted thrust line supplies the propulsive force.

A helicopter can be either nose heavy or tail heavy, depending upon how the projected thrust line passes relative the aircraft’s CG. The only difference is that it doesn’t have propeller thrust to contend with.

Generally, helicopters without horizontal stabilizers are always tail heavy at forward airspeed. The aerodynamic drag of the fuselage swings the CG aft of the rotor thrust line, the rotor thrust line being fixed in space by operating conditions.

An exception is the synchopter, with the outboard blade tips moving aft. A synchopter has an unbalanced component of rotor torque acting about the pitch axis that provides a nose up moment on the airframe. Think of a dragster with cambered wheels doing wheelies.
 
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A Pity!!!

A Pity!!!

How you guys have knoted and twisted this great sport with all this bull amazes me.I had no idea we had so many distinguished aeronautical enginners in the group.Since (it seems to me) that 90+% of all gyro accidents are caused by lack of training or bad judgment we could spend our time more wisely in this area.Why don't all you geniuses sell me your death machines cheap(that is if you own one).Problem solved!!! LC PS-then you will have the money to buy a nice Sofa with airbags---be safe-Joe PSS-all joking aside I believe most crashes are caused by the angle of the dangle being out of synchronization with those two small nuts located just behind the control stick-this problem can be corrected by replacement of said small nuts with a larger size--!!!!
 
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