Flying a model designed for indoor use outside is always a
dodgy proposition, but to fly this model with an all up weight
of less than 100g on a breezy evening was almost suicidal. I made
the fundamental mistake of listening to the voices in one's head
which undermine all reason. You know the ones: "That glitch
was a one off, it won't affect the next flight", "The
tranny voltage will be ok", "Only one more flight"
etc.
Having finished building my modified Lady Bug some three weeks
ago, I was really eager to see how it would perform. With this
in mind and with growing frustration with the windy weather, I
threw caution to the wind, literally, and sneaked off to King's
Park with said model.
The first attempt with a 7 cell pack resulted in a long run across the ground like a dodgem car, but no take off. This surprised me a little but, undeterred, and with the support of those voices, I inserted an 8 cell pack and tried again. This time the Bug shot off the ground into a vertical climb followed by the inevitable stall and a steep descent! I managed to recover the situation and after a very fraught few minutes managed to land without damage. After some investigation I decided that the CG was too far aft and looked for something to use as ballast. The only thing to hand was my bunch of car keys (He's always looking for new ways to lose these! - Ed), so these were attached to the nose and another attempt to fly was made. This turned out to be better, but full throttle still resulted in a steep climb and a porpoise type flight. Obviously some downthrust was required, but how? A trip to the bushes, (no, not for that), and a suitable size twig was found. This was about 1/8" dia and a quick calculation showed this would give approx 7 degrees of down thrust. Too much. Splitting the twig down the middle reduced this by half when wedged under the rear of the motor mount. The third attempt was much better but model is not very stable. Opening the motor up fully results in the model cavorting around the sky like an angry wasp. Reducing the power calms things down and she flies quite nicely. I suddenly realised that my keys were thirty metres above the bushes and in dire danger of being lost forever (Ah, only a paragraph behind, then! - Ed), which would be very difficult to explain to Erindoors, so I landed the model and, disregarding those voices, decided that enough was enough for this session.
Having returned home and thought about the session, I have decided that the only way to adjust the C of G is to relocate the servos. The motor also needs some permanent down thrust dialled in. When these mods have been completed I will try again, perhaps indoors when the wind will not be such a factor.