Tosh McCaber Posted August 7, 2019 Share Posted August 7, 2019 I have a Clouds High motor glider, which has a pylon rear mounted engine at high level at the back of the wing. When I launch the model, it has a very distinct downward pitch, trying to fly into the ground, especially on full throttle. Corrected temporarily with up elevator, the model flies pretty well under power during the flight, with no similar pitching down. I wonder whether I should be readjusting the thrustline of the engine with down thrust, i.e. pointing slightly downward towards the centre of gravity at the front. Or do I adjust it with some upthrust, i.e. pointing the engine downwards towards the tail boom? Or just leave it where it is ?? Answers will be appreciated! Quote Link to comment Share on other sites More sharing options...
alex nicol Posted August 7, 2019 Share Posted August 7, 2019 Hi Tosh, Good question. My guess would be the reason for the pitching on hand launch could just be the speed of launch, especially as it flys OK after the launch. Altering the thrust angle may affect normal flying. you'll get some more technically detailed responses to your question than mine Cheers Alex Quote Link to comment Share on other sites More sharing options...
Don Fry Posted August 7, 2019 Share Posted August 7, 2019 I've got one of these, and if chucked at full power, it hits the ground. At chuck, the motor, high above the wing pitches it down, there is little speed hence little lift, so not much lifting force to bring the nose up, and the elevator just is not big enough to drag the tail down fast enough to beat the nose, before it hits the ground. If you chuck it with a little power on, say 20% power, it floats away like a glider, sinks a bit, answers the elevator and climbs away. Opening the throttle now just gets it climbing faster, as the wing is in control. The fix would be fit a smaller prop, smaller motor, or just launch at a moderate throttle setting. And it's nice to get up quickly so I reckon leave alone. edit, Alex is right, chuck it fast enough, you get the wing working out of your hand, use as much power as you like. But I've got a transmitter in one hand, and prefer to chuck accurately. Edited By Don Fry on 07/08/2019 12:43:36 Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted August 7, 2019 Share Posted August 7, 2019 Built a Seibel from the RCM&E plan some years ago. It has the top mounted angled motor. On take off it just tried to drive itself into the ground. I would say that the motor needs a larger angle upwards away from the tail but I gave it up as a bad job in the end. Anyone want it? Quote Link to comment Share on other sites More sharing options...
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