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Thread: Gyroplane takeoff techniques

  1. #1

    Gyroplane takeoff techniques

    In the 50 or so hours that I have flown gyroplanes, I have had the opportunity to fly with probably 8 different instructors in 3 different countries. There seem to be two different schools of thought on proper (and safe) take-off techniques on "new generation" gyroplanes like the German-made AutoGyro (MTO, Calidus and Cavalon) which are equipped with powerful pre-rotators.

    The technique I learned to fly gyroplanes with (and which seems to be endorsed in Phil Harwood's manuals) essentially calls for pre-rotating to 200 RPM, then bringing the stick back and smoothly advancing the throttle to takeoff power.

    The other technique which I have learned from some of the instructors, particularly the ones who have experience flying gyroplanes with no-prerotators (hand-spinning) or less capable pre-rotators focuses more on bringing the throttle up slowly while closely monitoring the rotor RPM, and then going full (takeoff) power once the rotor is fully sped-up. I appreciate the rationale behind this; the idea being to prevent the unit accelerating to the point that the retreating blade stalls and you end with rotor blade flapping with a potentially disastrous outcome.

    While I understand that a better and more experienced instructor will teach this technique to his student, to instill good habits and of course not knowing what kind of gyroplanes his students will be flying in the future, I wonder if it is truly necessary for safe operations on gyroplanes with powerful rotators, and even if the pilot is not subjecting himself to a performance penalty when operating off shorter runways?

    According to the Pilot Operating Handbook for an MTO Sport equipped with the shorter "Sport" rotor, the rotor diameter is 8.0 meters (the "Standard" rotor diameter is 8.4 meters). Unless my calculations are faulty, that would with a 4 meters length from hub to tip, at 200 RPM the rotor tips would be travelling at 187 mph. Of course, the Rotor blade has a lifting or driven region (the outermost third of the span), the driving region (middle portion of the span) and the stall region which is the inboard part of the span. So lets say that the center of the lift region is at 3 meters, the linear velocity at this point would be around 140 mph. At 2 meters (probably well in the driving region) the linear velocity is about 93 mph and at 1 meter from the hub it is about 47 mph.

    Even with a lift-off speed at 35-45 mph, I wonder what the risk of flapping is at these types of linear velocities, and if there really is a necessity to use the second technique for consistently safe operations? I can't help but wonder whether powerful pre-rotators, sufficient horizontal tail surfaces, and thrust lines close to the Center of Gravity are all part of the design of new-generation gyroplanes to make them safer and simpler to operate.
    Last edited by Uwe Goehl 42764; 02-09-2017 at 03:45 AM.

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