Training for Emergencies

Doug Riley

Platinum Member
Joined
Jan 11, 2004
Messages
6,616
This exchange about the role of cojones in aviation reminds me of the inner wrestling match I had with myself about the safety of gyros.

After flying a VW-Bensen in my teens, I bought an Air Command 447 (early lowrider model with no H-stab) around 1987. It was fun to fly, but midday summer turbulence was nerve-wracking. Especially at higher cruise speeds, the nose would dip down in downdrafts and rear up in updrafts. As you added power and speeded up past best cruise (say, north of 70), the nose went lower and lower, and you had to hold continuous back stick. The sensation was like that of a child riding in a wheelbarrow, about to be dumped out.

I didn't know about HTL and lack of H-stab at the time. I just "sensed" that I was riding on a knife's edge. I told myself to grow a pair, and that this was just the way gyros flew. But I also knew about all those "zero G" crashes in Bensens.

I switched to FW ultralights for awhile (which routinely go to zero- and neg- G in that same turbulence, but safely unless you hit your head on the cockpit frame). Then information about H-stabs and HTL began to circulate. With these "new" safety measures in place, I went back to gyroing and lived happily ever after. Mostly.

I still have questions about combining (especially) an AOA-sensing, variable-RPM rotor with a centered flap hinge, though. It's one of a couple reasons that I feel that all the small gyros on the market are flying with scanty hard-engineering data in hand. In this respect, among others, none of them is the equivalent of a type-certified aircraft. We have both "known unknowns" and "unknown unknowns."

Which is not to say that I won't/don't fly them. I enjoy the experience enormously. But we ought to be honest with ourselves.
 

DavePA11

Active Member
Joined
Nov 16, 2015
Messages
986
Location
USA
Why exactly are they called "trikes"?
"Pendulaire" actually sounds more apt to me.
Pendulaire is too hard to say. I assume they are called trikes due to having three wheels? Apollo just replaced the trike wing with a rotor and called a gyro.

Jetlag - Trike flyers in France must have bigger balls than those in Massachusetts who only fly their trikes in the early morning and late at night when there is no wind or turbulence. :) Actually, I think most sold their trikes and upgraded to a gyro or fixed wing plane to fly more places…
 

fara

AR-1 gyro manufacturer
Joined
Oct 31, 2011
Messages
3,945
Location
Tampa, FL
Aircraft
AR-1
Total Flight Time
4000+ 380 gyroplanes. Sport CFI Gyro and Trikes
....

I still have questions about combining (especially) an AOA-sensing, variable-RPM rotor with a centered flap hinge, though. It's one of a couple reasons that I feel that all the small gyros on the market are flying with scanty hard-engineering data in hand. In this respect, among others, none of them is the equivalent of a type-certified aircraft. We have both "known unknowns" and "unknown unknowns."

Which is not to say that I won't/don't fly them. I enjoy the experience enormously. But we ought to be honest with ourselves.

AOA sensing variable-RPM rotor with a centered flap hinge?

So AOA sensing on which section of the blade exactly and how would a variable-RPM be done in autorotation exactly except for allowing pitch changes in flight for blade with a full mechanism to do it with some smart way of not getting it out of bounds (so just go heli basically) and centered flapping hinge like an offset flap hinge or what exactly do you mean. Offset flapping hinge should reduce 2 per rev a bit but not sure exactly what you mean?
 

Burrengyro

Gold Supporter
Joined
Dec 15, 2020
Messages
112
Location
Ireland
Aircraft
ELA07S and Montgomerie Bensen (project)
Total Flight Time
300
AOA sensing variable-RPM rotor with a centered flap hinge?

So AOA sensing on which section of the blade exactly and how would a variable-RPM be done in autorotation exactly except for a pitch changes in flight for blade with a full mechanism to do it and centered flapping hinge like an offset flap hinge or what exactly do you mean. Offset flapping hinge should reduce 2 per rev a bit but not sure exactly what you mean?
Hi Abid,
When you say "Offset flapping hinge, do you mean changing the position of the hub bar to something other than 90 degrees to the teeter bolt alignment? Please explain? Thanks, John H.
 

Doug Riley

Platinum Member
Joined
Jan 11, 2004
Messages
6,616
By "AOA sensing," I'm referring to disk AOA, not blade-element AOA. All gyro rotors are disk-AOA sensing devices.

A heli rotor is designed to be essentially constant-RRPM. A gyro rotor, in contrast, is a variable-RRPM device.

The heli rotor is designed to respond to changing G-load needs at constant RRPM, by means of increases or decreases in collective pitch and throttle (normally at the same time). The engine and rotor turn at constant RRPM, and throttle changes affect only manifold pressure.

The gyro's rotor, OTOH, responds to changes in its disk AOA. We commonly say that the rotor speeds up in high-G situations but, in fact, that's a backwards way of talking about it. What occurs is that disk AOA increases (because the pilot pulls the cyclic aft or an updraft hits from below). The rotor experiences an immediate increase in the blades' AOA* and therefore an increase in thrust -- but the rotor also speeds up. There's the variable RRPM effect.

This increase in rotor RPM at higher disk AOA is well and good in "G exceeding 1.0" scenarios (such as landing flares). But it's problematic at the low-G end of things. The rotor responds to low disk AOA by losing thrust and by slowing down. We call this a "low G" situation but, again, the rotor doesn't know about G's, it knows about disk AOA. It responds as designed, by losing RRPM.

Central flap hinges (whether teeter or other style) mean that only the rotor's thrust is applied to the gyro's frame. Your control and stability forces are akin to pulling from above on a rope attached to the teeter bolt. Less thrust and RRPM mean less control and stability. Slack the rope altogether, and you have zero control/stabilizing force.

If OTOH, you move the flap hinges outboard from the spindle, the centrifugal force of the blades also feeds back to the airframe, providing some control and stabilization force even at zero thrust. This is sometimes called the "T-bar effect."

The Cierva direct-cyclic gyros that retained the tilt-spindle cyclic system had slightly outboard flap hinges (perhaps intentionally taking advantage of this auxiliary supply of control authority), but they suffered as a result from high stick forces. You have to muscle the spindle around against the T-bar effect, once you move the flap hinges out from the spindle axis. A swashplate gets rid of this control-force trap... I believe Groen went through the process of re-discovering this dilemma; Jim Mayfield may want to comment.

My point is that the combination of centered flap hinge and autorotation has not been subjected to controlled experiments. We don't know exactly where the edge of the cliff is, or whether we can/should try to design our way back from it.
_____________________________________
* Notice that blade AOA is not the same thing as blade PITCH. We can have no collective control, and still have variable blade AOA (that is, the angle at which the air actually hits a blade element can vary). In particular, increasing disk AOA also increases blade AOA and vice versa. IOW, our variable disk AOA, though achieved with cyclic only, has the same aerodynamic effect on rotor thrust as a collective pitch control.
 

Doug Riley

Platinum Member
Joined
Jan 11, 2004
Messages
6,616
Here's a page from Gessow and Myers covering the offset-flapping-hinge idea. Note especially the comment that this rotor suspension setup provides control power in situations of low rotor thrust -- another way of saying "in low-G situations."

IMHO, the hobby-gyro "industry" has not explored this sort of meaty technical issue, instead unquestioningly copying Bensen.
 

Attachments

  • 20211007151350414.pdf
    892.5 KB · Views: 14

WaspAir

Supreme Allied Gyro CFI
Joined
Oct 21, 2006
Messages
5,061
Location
Colorado front range
Aircraft
Bell 47G-3B-1 / A&S 18A / Phoebus C, etc.
Total Flight Time
stopped caring at 1000
That might depend on which way you're going. With the nosewheel up front we call airplanes "tricycle" , but at the other end we call it "taildragger " while the FAA calls it "conventional gear" despite the wheel count being the same.

My old Sikorsky had wheels at each of the four corners ("quad"?), so at least that one wasn't a trike. My glider has one mainwheel in the middle and one tailwheel, so maybe it's a "bike" ?
 
Last edited:

Burrengyro

Gold Supporter
Joined
Dec 15, 2020
Messages
112
Location
Ireland
Aircraft
ELA07S and Montgomerie Bensen (project)
Total Flight Time
300
Here's a page from Gessow and Myers covering the offset-flapping-hinge idea. Note especially the comment that this rotor suspension setup provides control power in situations of low rotor thrust -- another way of saying "in low-G situations."

IMHO, the hobby-gyro "industry" has not explored this sort of meaty technical issue, instead unquestioningly copying Bensen.
Doug,
Many thanks for the comprehensive explanation of Gyro AOA and flapping hinges. Is teetering confined to teetering at 90 degrees to the axis of the teeter bolt? Will the pitch angle of the rotor blade change during rotation if the teetering angle is advanced or retarded from the normal 90 degree to the teeter bolt? Would such a change have any effect on 2 per rev vibrations? Thanks, John H.
 

Smack

Re-member?
Joined
Nov 3, 2013
Messages
774
Location
Georgetown
Aircraft
Kitfox IV / F1 Rocket / Magni M-16 / Beech 18 / Aviomania G2sA-2
Total Flight Time
500+
Doug, by "centered flap hinge" you have me pondering something; see if this is what you are saying.
Blade 1 has a hinge located at the center of the rotor assy vertical axis.
Blade 2 also has a hinge located at the center of the rotor assy vertical axis.
So, blade 1 and blade 2 hinge axes are concentric; for concept purpose, let's say it is a steel rod and Blade 2's bearings reach around Blade 1's bearings (I'm missing SolidWorks about now...) in a 'yoke' fashion.
Perhaps that blade flap axis is common (as above), but the blades are 'offset' a bit (not in-line as is common on teeter systems), then the 2 blades have identical attachment, just staggered.
So, when creating lift, both blades will cone upward and without something to stop them, won't they just continue to rise?
Would some sort of 'stop' (to limit upward coning) be required to transfer the blade's lift to the mast?
The above 'unlinks' the blades (no longer teetering), so each finds its own flight path independent of the other blade.
Does the above idea get across and what happens in that scenario?
Brian
 

fara

AR-1 gyro manufacturer
Joined
Oct 31, 2011
Messages
3,945
Location
Tampa, FL
Aircraft
AR-1
Total Flight Time
4000+ 380 gyroplanes. Sport CFI Gyro and Trikes
By "AOA sensing," I'm referring to disk AOA, not blade-element AOA. All gyro rotors are disk-AOA sensing devices.

A heli rotor is designed to be essentially constant-RRPM. A gyro rotor, in contrast, is a variable-RRPM device.

The heli rotor is designed to respond to changing G-load needs at constant RRPM, by means of increases or decreases in collective pitch and throttle (normally at the same time). The engine and rotor turn at constant RRPM, and throttle changes affect only manifold pressure.

The gyro's rotor, OTOH, responds to changes in its disk AOA. We commonly say that the rotor speeds up in high-G situations but, in fact, that's a backwards way of talking about it. What occurs is that disk AOA increases (because the pilot pulls the cyclic aft or an updraft hits from below). The rotor experiences an immediate increase in the blades' AOA* and therefore an increase in thrust -- but the rotor also speeds up. There's the variable RRPM effect.

This increase in rotor RPM at higher disk AOA is well and good in "G exceeding 1.0" scenarios (such as landing flares). But it's problematic at the low-G end of things. The rotor responds to low disk AOA by losing thrust and by slowing down. We call this a "low G" situation but, again, the rotor doesn't know about G's, it knows about disk AOA. It responds as designed, by losing RRPM.

Central flap hinges (whether teeter or other style) mean that only the rotor's thrust is applied to the gyro's frame. Your control and stability forces are akin to pulling from above on a rope attached to the teeter bolt. Less thrust and RRPM mean less control and stability. Slack the rope altogether, and you have zero control/stabilizing force.

If OTOH, you move the flap hinges outboard from the spindle, the centrifugal force of the blades also feeds back to the airframe, providing some control and stabilization force even at zero thrust. This is sometimes called the "T-bar effect."

The Cierva direct-cyclic gyros that retained the tilt-spindle cyclic system had slightly outboard flap hinges (perhaps intentionally taking advantage of this auxiliary supply of control authority), but they suffered as a result from high stick forces. You have to muscle the spindle around against the T-bar effect, once you move the flap hinges out from the spindle axis. A swashplate gets rid of this control-force trap... I believe Groen went through the process of re-discovering this dilemma; Jim Mayfield may want to comment.

My point is that the combination of centered flap hinge and autorotation has not been subjected to controlled experiments. We don't know exactly where the edge of the cliff is, or whether we can/should try to design our way back from it.
_____________________________________
* Notice that blade AOA is not the same thing as blade PITCH. We can have no collective control, and still have variable blade AOA (that is, the angle at which the air actually hits a blade element can vary). In particular, increasing disk AOA also increases blade AOA and vice versa. IOW, our variable disk AOA, though achieved with cyclic only, has the same aerodynamic effect on rotor thrust as a collective pitch control.

So you are basically worried about low G situations.
Same as trikes, PPC, PPG and even many helicopters.
 

Mayfield

Gold Supporter
Joined
Oct 30, 2003
Messages
911
Location
Avondale, Arizona
Total Flight Time
>14K hours
Yes Doug. Groen used an offset gimbal rotorhead on the Hawk 1 and 2. The control forces were pretty large. We flew it and achieved acceptable jump takeoffs at a quite high DA but it was not elegant.

The next rotorhead, incorporating cyclic and collective pitch and a conventional swashplate, worked well but it was possible for the pilot to pull in and hold too much collective pitch. This would pretty quickly result in RRPM decay to unsafe levels.

Since our rotorhead incorporated coning hinges (Think giant R22) I thought I could mostly design out this dangerous RRPM decay. I'm not an engineer, so I had to convince my engineering staff that the idea had merit. I built several wooden models ( wooden model sounds so much better than “popsicle stick contraption) and bounced the idea off Chuck Beaty. Chuck thought the idea was worth a try.

To test the idea, we turned the blade grips upside down and machined new control arms. We ended up with a pitch/cone coupled rotor. I believe the ratio was nearly 1 to 1. When taking off the pilot would pre-rotate to about 150% of flight RRPM. When ready to leave the ground you would pull collective. My memory says somewhere around 10 degrees of collective pitch. The aircraft would launch; the RRPM would quickly decay. As the RRPM decayed, coning would increase. As coning increased the control arms would reduce collective pitch which would stop RRPM decay and reduce coning as the collective pitch settled to about 3 degrees. The mechanism allowed the pilot plenty of time to lower the collective into a detent corresponding with the 3 degree of collective pitch setting. During the landing flare the pilot could pull pitch to essentially stop descent. Again, the pitch/cone couple prevented catastrophic RRPM decay. It was a wonderfully benign system for a gyroplane that would be terrible for a helicopter.

It was an elegant solution and worked well.
 
Last edited:

Tyger

Super Member
Joined
Nov 25, 2017
Messages
1,239
Location
Germantown, NY
Aircraft
Magni M16
Total Flight Time
420
With the nosewheel up front we call airplanes "tricycle" , but at the other end we call it "taildragger " while the FAA calls it "conventional gear" despite the wheel count being the same.
My understanding is that the original "taildraggers" had NO back wheel, just a skid that actually did drag on the ground. They actually had only two wheels. I believe those two wheels would still be considered "conventional" landing gear.
 
Last edited:

JETLAG03

Active Member
Joined
Jul 6, 2019
Messages
329
Location
france
Total Flight Time
300+ flexwing (pendulaire) newly trained on gyrocopter ((autogire)11h)
So you are basically worried about low G situations.
Same as trikes, PPC, PPG and even many helicopters.
To be fair @fara on a trike I have never worried too much about low g. I have with a passenger, left the seat completely when I entered a strong downdraft, least I think it was a downdraft, I know we fell like a stone, my mate made a great impression of a mouse with his squeal.:oops:.

P.s. larry's videos re trike flying are exceptional and helped me understand my pendulaire much better and the fact that the pendulaire can easily cope with meteorlogical conditions that would makes most men squeal.

p.p.s. I don't think my "crown jewels" are bigger than anyone elses, but, with age, they hang lower
 

fara

AR-1 gyro manufacturer
Joined
Oct 31, 2011
Messages
3,945
Location
Tampa, FL
Aircraft
AR-1
Total Flight Time
4000+ 380 gyroplanes. Sport CFI Gyro and Trikes
To be fair @fara on a trike I have never worried too much about low g. I have with a passenger, left the seat completely when I entered a strong downdraft, least I think it was a downdraft, I know we fell like a stone, my mate made a great impression of a mouse with his squeal.:oops:.

P.s. larry's videos re trike flying are exceptional and helped me understand my pendulaire much better and the fact that the pendulaire can easily cope with meteorlogical conditions that would makes most men squeal.

p.p.s. I don't think my "crown jewels" are bigger than anyone elses, but, with age, they hang lower

Yeah I have left my seat a few times but in 3500+ hours of flying that's very very rare and does not last long at all.
Your gyro with a decent tail (HS) will also handle a transient situation like that. There is a point if the air comes from top of the disc or wing going below, the rotor RPM will slowdown. Once it slows down about 15% or more, its next to impossible to recover. That's the part that does not happen in a trike but what will happen in a trike is if that conditions lasts too long, you will get into a tumble and tumble has a self propelled acceleration with each rotation. But those conditions are basically thunderstorms, severe virga and really really strong downdraft with turbulence and gusts. Airplanes don't want to be flying in those conditions either. We had a RV-7 tear its wings off in 2019 right from the hanger we are at when it flew into an embedded small thunder cell over the Gulf of Mexico killing both pilots. Tragic loss.
 

Doug Riley

Platinum Member
Joined
Jan 11, 2004
Messages
6,616
Brian: Re your Post #22:

What keeps our blades from folding up in response to their own lift is not the rigidity of the (Bensen-style) hub bar, but rather the outward pull of centrifugal force. Cent. force* pulls out at right angles to the rotor's rotational axis, while lift pulls up; the combination of the two settles the blade into a coning angle of a few degrees only. It doesn't matter if the blade is free to rise as much as it wants; unless RPM is lost catastrophically, it won't rise more than a few degrees because cent. force won't let it. There have been rotors with centered, but independent, flap hinges designed as you described. Chuck Beaty built one that looked like a giant door hinge, and some old helicopters had blade-root yokes somewhat like the one you're picturing.

If the flap hinge is not at 90 deg. to the blade's spanwise axis, then the hinge is said to have a "Delta three" offset. The A&S 18A uses some of that. It provides the 18A with an automatic reduction in collective pitch as the blades use up their stored rotational energy and slow down after a jump. They drop from helicopter pitch to gyro pitch.

Jim Mayfield is describing a different way of achieving the same effect as a Delta three offset, while still employing a rigid teeter bar and hinge: in either case, pitch-cone coupling is the result.

Fara, yes, I am concerned about low-G situations. And, yes, trikes and teetering-rotor helos and PPCs have issues with low G, too. (BTW, trikes may have been so named to distinguish them from the original foot-launched powered hang gliders. Just a guess.) I don't know of any trikes or PPC's that have achieved STC, though. I don't know if one could pass.

But the situation with gyros and zero G (= zero disk AOA) is, in any event, unique. Our RRPM is variable (but not instantly), and is related to disk AOA. As you point out, loss of RRPM is a one-way street beyond a certain point. Most, if not all, gyro low-G crashes have clearly resulted from airframe instability (HTL, engine torque and/or low center of drag), which is preventable by design, but low RRPM is certainly another route to disaster.

My point is not that Bensen-style gyros are clearly and unavoidably uber-dangerous. Still, in discussing gyro safety, we shouldn't ignore the fact that these issues have not been explored systematically to see just where the safe edge IS, or how much better some other setup might be. This lack of knowledge is itself a risk factor: a "known unknown." Compare a C-172. It's pretty unlikely that any unexplored coffin corners are left in one of those.
__________________________________
* No, it's not really a force; it's an inertial effect, but the difference doesn't matter here.
 

fara

AR-1 gyro manufacturer
Joined
Oct 31, 2011
Messages
3,945
Location
Tampa, FL
Aircraft
AR-1
Total Flight Time
4000+ 380 gyroplanes. Sport CFI Gyro and Trikes
Brian: Re your Post #22:

What keeps our blades from folding up in response to their own lift is not the rigidity of the (Bensen-style) hub bar, but rather the outward pull of centrifugal force. Cent. force* pulls out at right angles to the rotor's rotational axis, while lift pulls up; the combination of the two settles the blade into a coning angle of a few degrees only. It doesn't matter if the blade is free to rise as much as it wants; unless RPM is lost catastrophically, it won't rise more than a few degrees because cent. force won't let it. There have been rotors with centered, but independent, flap hinges designed as you described. Chuck Beaty built one that looked like a giant door hinge, and some old helicopters had blade-root yokes somewhat like the one you're picturing.

If the flap hinge is not at 90 deg. to the blade's spanwise axis, then the hinge is said to have a "Delta three" offset. The A&S 18A uses some of that. It provides the 18A with an automatic reduction in collective pitch as the blades use up their stored rotational energy and slow down after a jump. They drop from helicopter pitch to gyro pitch.

Jim Mayfield is describing a different way of achieving the same effect as a Delta three offset, while still employing a rigid teeter bar and hinge: in either case, pitch-cone coupling is the result.

Fara, yes, I am concerned about low-G situations. And, yes, trikes and teetering-rotor helos and PPCs have issues with low G, too. (BTW, trikes may have been so named to distinguish them from the original foot-launched powered hang gliders. Just a guess.) I don't know of any trikes or PPC's that have achieved STC, though. I don't know if one could pass.

But the situation with gyros and zero G (= zero disk AOA) is, in any event, unique. Our RRPM is variable (but not instantly), and is related to disk AOA. As you point out, loss of RRPM is a one-way street beyond a certain point. Most, if not all, gyro low-G crashes have clearly resulted from airframe instability (HTL, engine torque and/or low center of drag), which is preventable by design, but low RRPM is certainly another route to disaster.

My point is not that Bensen-style gyros are clearly and unavoidably uber-dangerous. Still, in discussing gyro safety, we shouldn't ignore the fact that these issues have not been explored systematically to see just where the safe edge IS, or how much better some other setup might be. This lack of knowledge is itself a risk factor: a "known unknown." Compare a C-172. It's pretty unlikely that any unexplored coffin corners are left in one of those.
__________________________________
* No, it's not really a force; it's an inertial effect, but the difference doesn't matter here.

Doug:
Every kind of aircraft has limitations and they are supposed to be flown within those limitations.
Trikes like Airborne Australia's 912XT have a TC with CASA and that TC is based on regulations based on BCAR Sec S which is also used for airplanes. Trike wings do structural testing for positive as well as negative G but that is simply for structural and transient G conditions. If you ever get into a negative G in trikes that is more than transient you basically have no control whatsoever and you are in danger of a tumble and once it starts, basically you are gone besides pulling a BRS if you have enough height.
This does not mean they can't be TC'ed. This just means low and negative G is out of their flight envelope and they are tested for stability in pitch as airplanes are.
May be pitch stability and dampening in older gyroplanes was not that good and that would hold your statement that most if not all low G conditions are a result of airframe but that really isn't true of modern gyroplanes. It requires deliberate pilot input and action to get there. Center Line Thrust only can make a case in the static condition for thrust line being high (meaning 0 forward speed) but that is not where the fatal accidents are happening and that ought to put a huge monkey wrench in assigning that as the major cause of most of these accidents. I know there is a big tendency n this forum by people like Chuck Beaty to prescribe solutions like center line thrust with a small close in cruciform tail (ala Dominator) yet that is no guarantee of not getting out of control with that. I have about 12 hours on a light Dominator I didn't feel any more in or out of control on it than anything else. It just shook more because it probably was not precision made or balanced. I remember a fatal accident in a single seat Dominator when I first got on this forum in Florida with a new pilot who had trained on a MTO but had no training on a Dominator and soloed on his Dominator and on the very first flight got into PIO, into low G and crashed and died. Clearly training on type was the thing missing because he was judged ready to solo in a MTO or like aircraft by 2 instructors. The Dominator's center line thrust or its cruciform tail did absolutely nothing to prevent PIO or to allow recovery from his PIO and subsequent loss of control.

At the same time looking at accidents with Magni, MTO and this type of gyroplanes, the stats do not favor your assertion. Its been pilot inputs and actions that have created issues just as it did in that Dominator. Pointing to training in type being a bigger factor than anything else. In trikes its the same conclusion. Training in specific type or style turns out to be more important than your time as a pilot in other categories or types of aircraft. A UK insurance study determined the same result for fatal accidents in 2007. Most of the fatal accidents were high time pilots coming to a new category of aircraft and most fatal accidents were in calm evening clear conditions.

The safe edge is fairly clear to me. If you are flying a gyroplane and take it to low G's for more than a transient time (like experienced in weather conditions generally), you will slow the rotor and once that gets down to a certain point, its not recoverable. Also if you are going to unload the rotor using your engine thrust by abrupt pitch inputs at full power for example, you will slow the rotor down. If you do extreme sustained side slips/skids you can start to unload the rotor and if you do not correct it, it will again slow the rotor down. The rotor only knows airflow through it and when its starts flowing from the wrong angle, you are in danger.

If these limitations are not acceptable, people should not be flying trikes, gyroplanes, PPC. PPG and I would even dare say helicopters and go to aerodynamic control like in airplanes. Certainly a lot of people do. I certainly know more than a dozen people who died due to tumbles in trikes but yet I would get into a trike without a second thought because I know what I should not do and I am trained in them and if there was a new model that is unlike others I have flown before, I would have the humility to go up with someone familiar enough times to get familiar with it before solo. Its the same thing I would do with airplanes or gyroplanes. That's just what I believe to be reasonable and follows common sense.

Trikes are dead simple and very very safe when flown normally by a properly trained pilot whose ego is smaller than his/her shadow. They don't handle turbulence well so flying them early morning or late evening is best and they are a sport for generally younger pilots because they are definitely physical.

Oh there sure is a coffin corner in a 172 (assuming the slang use of the term not its actual high altitude stall meaning). Try doing an accelerated uncoordinated stall in it from 500 feet. You will be playing with fire. Seen it when someone crashed right into the ground and died. But why would you do that just because you were doing a downwind to crosswind turn from base to final and overshot your runway target and banked it 60+ degrees to make it back. That's not the fault of the plane. That coffin corner kills more GA pilots than any other single thing to this day. You can say this really isn't a coffin corner because its a known issue well so is the low G, extreme side slip, don't hang on the engine thrust limitation of 2 blade teetering rotors. Don't go there and take training. Want to do aerobatics, go to aerodynamic control not a trike or gyroplane. There is no out from one mistake. It would be foolish.
 
Last edited:
Top