Understanding Gyroplane Flight Controls.

WaspAir

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Straight stick, full back, is good. The Adding a tilting to the side of the crossing wind decreases rpm acceleration,
and not decreases the torque of roll like that of a fixed wing in asymmetrical flight, because this effect does simply not exist on a rotary wing.
Torque was not my concern. I was thinking about whether you might be using a lift vector pointed slightly to the side to resist drifting from the wind pushing you sideways on the runway. Something like a slip only while on the ground. It's routine in gliders and I did it often with wheeled helicopters.
 

XXavier

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I still don't understand that. If I have to give an initial control offset for a crosswind takeoff, I do not change that offset till I'm airborne and changing my direction. If I were to follow your explanation, then I would be constantly taking off the offset to cater for the apparent change in direction of the wind during the take off. In which case I would be drifting to the side along the actual direction of the wind.

Make an easy experiment: with a moderate wind, run at 90º to the wind bearing a flag. You'll see...

Concerning the drift, it will be always there, because the lateral component, the crosswind, does not disappear, but you have the rudder to compensate it from the instant you lift the front wheel...
 
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thomasant

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My job is to keep my students and machine safe and so I try and follow the techniques that have been advocated. I agree that a thorough understanding is good.
But thank you for your explanations.
 

Jean Claude

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I was thinking about whether you might be using a lift vector pointed slightly to the side to resist drifting from the wind pushing you sideways on the runway. Something like a slip only while on the ground. It's routine in gliders and I did it often with wheeled helicopters.
Oh, yes of course, but it is a very little: For example a 20 kts crosswind pushes the fuselage laterally by about 100N.
If the rotor lift is 4500N then this requires 1.3 degrees of tilting ie ATAN(100/4500)
 

thomasant

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Oh, yes of course, but it is a very little: For example a 20 kts crosswind pushes the fuselage laterally by about 100N.
If the rotor lift is 4500N then this requires 1.3 degrees of tilting ie ATAN(100/4500)
Very interesting. What about the moment arm from the wheel axis of about 1 meter to the CG, of the 100 N acting on the fuselage. Will the moment arm make a difference? What about a gust of another additional 50N acting on the fuselage? Will these forces tend to have an unsafe effect on the take off, if not compensated with cyclic tilt?
In the tandem Air Command that I had, I used to get pushed off to the side quite a bit to the edge of the RW during T/O, even with cyclic offset and opposite rudder compensation. In the Alouette III helicopter that I flew, we were taught to tilt the cyclic into the wind during ground taxi just as Wasp Air describes it.
Sergio Pensotti from our gyro club flipped his M 24 gyroplane during prerotation in strong crosswind with a strong gust, while stationary, about two years ago.
In any case, I still follow the laid down procedures by the FAA manual, even though the mathematical calculations are definitely enlightening.
 

Vance

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Thank you all for your thoughtful input.

At the risk of being divergent or over simplistic I practice and teach to guess how much to tilt the disk into the wind at lift off.

I start the takeoff roll with the cyclic fully back and centered and as the nose comes up I tilt the disk into the wind as I come forward with the cyclic to keep the nose wheel near the ground.

If I guessed correctly the gyroplane will rise straight on liftoff without correction.

Too much or too little tilt will require an immediate input on lift off to remain over the centerline.

I feel drifting across the runway just after takeoff is dangerous as the wind may set me back down.

I do not steer with the cyclic during the ground roll and usually keep her pointed down the runway with the rudder until I am far enough above the runway to feel confident that a gust won’t set me back down.

This uncoordinated flying reduces my rate of climb.
 
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jm-urbani

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As a (thankfully former!) gyro instructor, I agonized over crow-hops.

The criticism of them is well-founded: they tend to teach you to fly behind the power curve, and they put you near the ground where a minor slip-up can result in unplanned ground contact.

The problem with abandoning them: a light single-seat gyro such as a Brock, Bensen, Air Command, Gyrobee, or Dominator grosses at less than half the trainer's gross. This means that the 1-seater's control response and torque reactions are MUCH snappier. This can put a newbie (used to a relatively leisurely half-ton trainer gyro) way behind the machine.

Moreover, low mass (especially in the case of a draggy open gyro) means much less gust penetration and extra-quick loss of airspeed when the power goes away.

Finally, single-place gyros are quite close-coupled compared to tandems. This, again, makes them comparatively twitchy.

I learned by first gyrogliding for 50 or so hours, then doing close-to-ground hops for another 50. I didn't crash or bust anything.

I didn't just "crow-hop," though. I started with that, but then proceeded to low S-turns and abbreviated full-bore climbouts (maybe 75 feet up) followed by steep, idling glides to the runway. Lastly, I did many full-throttle runs at maybe 5 feet, building as much airspeed as I could before running out of runway and landing at the end. I could make it up to 70 mph-plus before I had to put down. I had a 3,000-foot, paved runway at a rural airport.

In all this, I was trying to stay ALIVE in the era of one-a-month neg-G/porpoising fatalities in Bensens. There was the wreckage of one such fatal Bensen crash dumped behind a shed at my airport, in case I needed sobering up. I visited it often. I'd be damned if I was going to start porpoising at altitude because I got behind my craft!

My first pattern was frankly terrifying. But I didn't porpoise. In fact, I handled the following rapid series of engine flameouts and off-field landings without incident.

So, reluctantly, I think crow-hops are necessary for training/transitioning to fly a single-seat gyro. They are unnecessary, and should be omitted, for those who will fly only heavier 2-place gyros.

Like democracy, crow-hopping is the worst system ever invented, except for all the others. For single seat gyros, that is.
I have personnaly done a couple of crow hops when I transitionned from the magni to my monoseater,
I had only 50 flight hours experience and my gyro had been tested before by my instructor
as I had built a strong pre rotator I did not have to make many attemps, I only presminned 220 rrpm and then I have pushed the throtttle gently to find out when the front wheel would lift , and when it did lift I when back to idle, I did it 4 times and the third time I pushed the stick and flex on ground effect
the tricky thing is that when you flight at 1m above the ground to tend to reduce the throttle to land back and it is not a good thing because if you happen to climb higher and land the same way you crash .on my fourth attemp I did climbed 5 meters high (15 feet) and to land I when back to idel and did not forget to push the stick to keep my airspeed, and landed normal
I went it the pattern the fifth time and all went well
I don't think I will do the same this time with the tandem I will test , I will take off and land back at 66% of the runway, the goal will be to be able to land quickly in case something goes wrong, but I have 350 hours experience now ..
 

XXavier

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I have personnaly done a couple of crow hops when I transitionned from the magni to my monoseater,
I had only 50 flight hours experience and my gyro had been tested before by my instructor
as I had built a strong pre rotator I did not have to make many attemps, I only presminned 220 rrpm and then I have pushed the throtttle gently to find out when the front wheel would lift , and when it did lift I when back to idle, I did it 4 times and the third time I pushed the stick and flex on ground effect
the tricky thing is that when you flight at 1m above the ground to tend to reduce the throttle to land back and it is not a good thing because if you happen to climb higher and land the same way you crash .on my fourth attemp I did climbed 5 meters high (15 feet) and to land I when back to idel and did not forget to push the stick to keep my airspeed, and landed normal
I went it the pattern the fifth time and all went well
I don't think I will do the same this time with the tandem I will test , I will take off and land back at 66% of the runway, the goal will be to be able to land quickly in case something goes wrong, but I have 350 hours experience now ..

Interesting... I have never tried a single-seater, and didn't know that they were so tricky...
 

All_In

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PRA recommends having a CFI or at least a pilot on the ground with a radio who has experience in the single place you are transitioning too.
It has saved several near-crash or hard landing. It's almost like having them in a two-place telling you what to do.
 

Resasi

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With all the single seat training I was associated with we considered two way communication essential, and whenever possible a chase vehicle proceeding beside the gyro with the Instructor closely observing if we were training only one pilot.

Where this was not possible at least an observer at the beginning of the run, and one posted further down the runway in a position to observe the latter part of the run.

On one of the longest runways at Rissington where the longest runway went over a hill we had one observer at the beginning, one at the brow and one at the end.

At the height of our training we had up to six gyros and sometimes more training one behind the other taking turns to go up the runway on one side with the other for returning gyros. The runways at that service airfield were very wide. The group I was with at Henstridge and later at Rissington probably trained the most single seat gyro pilots during that period. At one stage we had around 34 gyros in the hanger.
 

jm-urbani

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it depends on the gyro you are using .. some are tricky, even vicious with a lot of motor effects... some are easy (ctl+tall tail)

most of the time the people trained on tandem have difficulties because of the fact the prop turns on the reversed direction compared with the 4 stroke engines ... this is the case on a magni M18 when taking of you must press left ruder and put the stick rigth ( the contrary of the M16)
I did not havr this issue with a tall tail you don't press any ruder on take off and you leave you stick in neutral position ... just greate you can focus only on the pitch axis



vi
Interesting... I have never tried a single-seater, and didn't know that they were so tricky...
 

fara

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I have not been looking at this forum lately too much. The crosswind takeoff is almost the same as normal takeoff except at the start you have the disc slightly tilted into the wind for pre-rotation and takeoff run, the takeoff will result in downwind tire lifting off slightly before upwind tire on the mains. Once up to speed the disc should ideally be level as in normal takeoff. If you a bit faster than normal break ground speed (38 knots in AR-1 and say you went to 42 knots before you allowed it to unstick), it may jump up and the propeller torque effect reaction (tilting due to torque) and crabbing into the wind will be felt more quickly or abruptly. Just being prepared to expect those may be helpful. P-factor may also have an effect initially depending on the attitude. Initial climbout the tilt in the rotor disc should be reduced to level and coordinated flight resumed to get good climbut. Leaving un coordinated control input in will reduce performance.

Tony mentioned someone flipping over their Magni gyro standing still while pre-rotating in a crosswind due to an unexpected gust. I can almost guarantee which way his rotor disc was tilted. The wrong way compared to the gust (or tilted way too much) and most likely propeller torque effect and mismanaged tilt of the rotor both combined and conspired to flip it over. By the time you are reaching 160+ RRPM, it seems in most crosswind conditions you can start to flatten and level the disc out in my experience.
 
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