This is it, the weathers OK and the time is right, so pack up the car and head for the field. When I arrived the steady breeze had dropped to an almost flat calm, still this is better than going the other way.
First things first, a few photos just in case the worst happens, here’s one on the starting box and table.
With the engine nicely warmed up a couple of runs to check the ground handling; no problems, straight as a die, but then it would be, the gyro’s doing all the work not me! Gradually build up the speed to see if the rear folding sections of the lower wings stay in place over the bumps and she’s nearly airborne, close the throttle and everything’s fine so the next one is for real.
This time a bit more throttle to ensure we reach flying speed and away she goes, as soon as the wheels leave the ground the left wing drops and it needs full right aileron just to keep level. Too late now to abort so gain height and see what we can do. A few clicks of right rudder eases the problem but when the throttle is closed a sudden right turn, it’s obvious that landing is going to be quite a challenge so I decided to cruise around at a safe height to let the nerves settle. Gradually reducing throttle and adjusting rudder trim line up for a landing, got to get this right as any sudden throttle change will result in an equally sudden turn! More by luck then judgement I hit the square and she’s down in one piece.
Time for the post mortem. First the ailerons are virtually useless so must use CAR (coupled aileron rudder). The trim changes with throttle indicate the need for more engine right thrust. I had intended to build it at 0º, as I have done with all my previous models, but the club aerobatic expert Bob Wasson gave the model the “once over” and declared that there was about ½º left thrust (note this is an expert not an “expert”!!) and he suggested I adjust the thrust line to 2º right thrust. At home careful measurements proved he was correct about the left thrust and I duly modified the bearers; could only get about 1½º right because of lack of room under the cowl.
In the background of this photo Bob is preparing his aerobatic model.
I mixed CAR and tried again a couple of weeks later, what a difference, the model was now completely controllable but still turned left as the throttle was opened, if I’d managed to get the full 2º as suggested I’m sure it would have “flown on rails”. I now also mix in a small amount of right rudder with throttle and she flies like a “good un”. A wonderful sight on a low, slow pass with the Laser burbling away at ¼ throttle, it doesn’t get much better than this!
yup a truly excellent thread greyhead,very very informative and with the pictures us non aero modellors can see how these things are put togethor and the thought process and occasional "redesign" all fits togethor.
excellent m8
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