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Previously, I made some speed runs at the recommended maximum substainable engine rpm, and I discovered I had to hold considerable forward stick pressure to keep from climbing. This lead to the idea that if I reflexed the ailerons it would spoil lift and this would remove some back pressure and some of the corresponding drag. I shortened the aileron push/pull tubes so that the ailerons could be reflexed to five degrees. On September 18, 2004, I flew up and down wind flights and obtained the following average gps speeds.
With the reflexed ailerons, I had to hold more forward stick than before to keep the FireFly from climbing. So the idea of reducing lift to reduce drag was invalid because the reflexing moves the lift center rearward so that one has to place greater load on the tail to keep from climbing. It appears that as one flies the FireFly at greater than trimmed engine cruise speed, one has to add trim to the elevator control system. Another option would be to trim the FireFly out at max speed and accept whatever one gets for the desired engine cruise rpm. Also, one could raise the thrust line to see if it would push the nose down as the thrust increases and reduce the need for elevator trim plus reduce high speed drag. I lowered the thrust line to keep drag down at cruise, but I did not take max speed data before lowering the thrust line.
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