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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anthom

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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)
 

anthom

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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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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...
 

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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.
 

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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Vance

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In my opinion based on my experience flying The Predator in a cross wind takeoff with the wind from the left the disk should start out flat because tilting it left slows the pre-rotation and rotor spool up. I leave the cyclic centered until around 200 rotor rpm gradually moving the cyclic left as the rotor gets a bite. If I guess the position of the cyclic correctly she will lift off without correction and both main tires will lift off at the same time.

I will typically have right pedal in to manage her tendency to turn into the wind. The Predator has a free castering nose wheel.

In a cross wind takeoff with the wind from the right the disk should still start out flat and gradually move the cyclic right as the rotor gets a bite.

I will typically have left rudder in and guess at the amount of right cyclic on lift off.

If done properly she will lift off without correction and both main tires will lift off at the same time.
 

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Doug Riley

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I always prerotate with the gyro facing into the wind, not with the wind entering the disk crossways.

I do so off to the side of the taxiway, where possible leaving room for FW traffic stacked on the taxiway behind me to pass and take off ahead of me if they wish. If I'm still spinning up, I wave them past and invite them on the radio to go ahead.

A gyro sitting on the end of the active runway spinning up blades (possibly cross-wind) puzzles fixed-wingers and monopolizes runway time. It also creates the possibility that another aircraft could appear on final and be flustered that you were holding out there on the active, not yielding but also not rolling.
 

fara

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In my opinion based on my experience flying The Predator in a cross wind takeoff with the wind from the left the disk should start out flat because tilting it left slows the pre-rotation and rotor spool up. I leave the cyclic centered until around 200 rotor rpm gradually moving the cyclic left as the rotor gets a bite. If I guess the position of the cyclic correctly she will lift off without correction and both main tires will lift off at the same time.

I will typically have right pedal in to manage her tendency to turn into the wind. The Predator has a free castering nose wheel.

In a cross wind takeoff with the wind from the right the disk should still start out flat and gradually move the cyclic right as the rotor gets a bite.

I will typically have left rudder in and guess at the amount of right cyclic on lift off.

If done properly she will lift off without correction and both main tires will lift off at the same time.
That would be true but I am talking about pre-rotation with stick forward. You start with disc very slightly tilted into the wind and as you get to 130+ RRPM you level it and do the rest normally
 

fara

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I always prerotate with the gyro facing into the wind, not with the wind entering the disk crossways.

I do so off to the side of the taxiway, where possible leaving room for FW traffic stacked on the taxiway behind me to pass and take off ahead of me if they wish. If I'm still spinning up, I wave them past and invite them on the radio to go ahead.

A gyro sitting on the end of the active runway spinning up blades (possibly cross-wind) puzzles fixed-wingers and monopolizes runway time. It also creates the possibility that another aircraft could appear on final and be flustered that you were holding out there on the active, not yielding but also not rolling.

Now imagine a new student solo pilot doing all this. Handling pre-rotation, holding brakes, talking on radio, waving them by hand (which hand because one is on the stick and one is on the brake/throttle) and then managing the rotors to taxi out going from headwind to crosswind, all the time rotor RPM is doing what it will do so he/she is having to keep an eye out on them as well. No wonder new pilots flap the crap out on takeoff because their rotor RPM gets too slow and they overrun the rotors easily and flip over or chop the tail.

Procedures for new pilots should be simple and straightforward as much as possible because that is already too much. No other single engine non-high performance, non-complex aircraft requires as many things and steps to be managed as a gyroplane in a takeoff. Why add even more to it for new pilots? Does not make sense to me.

There is no serious problem I have encountered announcing on the radio that gyro is taking active runway with delayed departure. One minute delay for pre-rotation at position and hold on runway xx.

Of course you would not announce that if someone was on the final. The runway is theirs once they call out final (unless it's a long straight in GPS approach 10 miles out). Usually after some practice it takes only 40 to 45 seconds to the point where gyro can start the takeoff roll at around 180 rotor RPM. Just my opinion.
 
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Vance

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Now imagine a new student solo pilot doing all this. Handling pre-rotation, holding brakes, talking on radio, waving them by hand (which hand because one is on the stick and one is on the brake/throttle) and then managing the rotors to taxi out going from headwind to crosswind, all the time rotor RPM is doing what it will do so he/she is having to keep an eye out on them as well. No wonder new pilots flap the crap out on takeoff because their rotor RPM gets too slow and they overrun the rotors easily and flip over or chop the tail.

Procedures for new pilots should be simple and straightforward as much as possible because that is already too much. No other single engine non-high performance, non-complex aircraft requires as many things and steps to be managed as a gyroplane in a takeoff. Why add even more to it for new pilots? Does not make sense to me.

There is no serious problem I have encountered announcing on the radio that gyro is taking active runway with delayed departure. One minute delay for pre-rotation at position and hold on runway xx.
Based on my research new pilots have uncomanded rotor excursions because they have not learned rotor management and don’t know what to do when the rotor warns them of impending trouble.

In my opinion too much airspeed for the rotor rpm and a mishandled cyclic is what causes the retreating blade to stall and the advancing blade to sail.

Doug’s technique works well with many of the gyroplanes I have flown and it is how I was taught by Greg in the American Ranger.

I feel using standard radio phraseology at a non-towered airport has value.

There is no active runway at a non-towered airport and there is no position and hold at any airport in the USA.
 

Vance

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In my opinion if a gyroplane is set up correctly and wheel balancing is done well a gyroplane will lift off when she is ready and I recommend against having a rotate speed (unstick speed).

Too often new to gyroplane pilots want to fly like a fixed wing with a Vr (rotate speed) and don’t pay enough attention to rotor management.

In my experience if wheel balancing is done well P factor is not noticeable in an open tandem gyroplane.

If I have one main tire lift off before the other in a tandem it is an indication that I did not have the proper left to right disk angle (cyclic position).

Takeoff mishaps are one of the leading causes of our high insurance rates so I feel it needs to be taught well.
 

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JETLAG03

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Limited gyro time but when flying flexwings I always believed that the most dangerous parts of any flight are the unstick and touchdown.

The wheel balancing whilst I understand some of its benefits put the student in the vey high risk part of takeoff, highly at risk from gusts or minor over controls where there may not be room or time for correction
 

Doug Riley

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Fara, both staying off the active while pre-spinning, and pre-spinning out of the way of traffic flow on the taxiway, are attempts at courtesy to fellow pilots. Neither of these actions is mandatory (well, unless you are Part 103, in which case arguably they ARE mandatory). If these courtesies overwhelm the new pilot, he/she can skip them until more comfortable. Courtesy and understanding go a long way to erase the evil reputation of gyros in the G.A. community.

I think also that there is some added safety in not sitting at the end of the active whilst spinning blades. The fixed-wingers just don't know what to make of this (unless you've met them beforehand and have briefed them on the peculiarities of gyro ops). The closest analogous task for them is a mag-check runup. That is done -- yup -- in the runup zone off the runway.

Not every landing aircraft is announcing as he/she proceeds around the pattern. Sometimes a landing airplane appears out of nowhere. I've had them land in front of my gyro just as I'm starting my takeoff roll. A spindly little gyro parked on the numbers is hard for them to see.
 

BEN S

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Want students to learn rotor management?
Start them in a single seater, cover the rotor rpm gauge if present and make them hand prop and drop down in the seat and get the rotors spun up on a calm day.
Gotta start with the basics. If they are incapable of doing this, don't advance them to the 120,000 dollar fancy rigs.
This methods really sears into fixed wing pilots that they are NOT flying a fixed wing.

Im sure I can hear a ton of negative feedback coming from people who have possible never even done it themselves saying how this is like learning to drive a Model T before giving them a Cadillac.
 

Vance

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Limited gyro time but when flying flexwings I always believed that the most dangerous parts of any flight are the unstick and touchdown.

The wheel balancing whilst I understand some of its benefits put the student in the vey high risk part of takeoff, highly at risk from gusts or minor over controls where there may not be room or time for correction
In my opinion wheel balancing is how a gyroplane tells the pilot when she is ready to fly.

In my opinion planting the nose during takeoff can lead to the rotor not accelerating normally and increasing the acceleration of the aircraft.

I feel too much air speed for the rotor rpm combined with back cyclic is what causes the retreating blade to stall and the advancing blade to sail.

With hard linked steering planting the nose can lead to confusion about what the rudder is doing.

Most of the pilots operating handbooks I have seen recommend wheel balancing.

Once wheel balancing is achieved I teach clients to progressively bring the cyclic forward as the rotor rpm and airspeed increase to keep the tire near the ground until liftoff.

In my opinion a properly set up gyroplane will lift off when it is ready near Vx when wheel balancing is done well.

For some wheel balancing is a challenging skill to learn and they look for a short cut like planting the nose on takeoff or some predetermined cyclic position.

The NTSB has recorded many takeoff mishaps from uncomanded rotor divergence. In the most basic terms, too much airspeed for the rotor rpm combined with bringing the cyclic too far back for the rotor rpm and airspeed.

In The Predator the I put in full throttle above 180 rotor rpm and the nose will come up somewhere around two hundred rotor rpm and the cyclic is progressively moved forward as airspeed and rotor rpm increases.

I will not approve solo flight for a pilot who cannot keep the nose tire just off the runway (less than an inch) for the duration of the takeoff roll.
 
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