Hi all,
As there is no "Trimming" forum and it was electric powered I thought I would ask this here....

I just totalled my Electric Gotchastreak on the 3rd flight.  , It has been a never ending succession of disasters ever since I pulled the bits out of box but that's another story, finally it was finished and I got to fly it. 1st flight was frightening, hopelessly underpowered. Cheap Chinese batteries (Or very expensive balance leads depending on your point of view). It would not reach the programmed RPM so I saw the flight out with a few loops and that was it, I thought I just had the RPM set wrong so upped it for the 2nd flight no difference, I then put a decent battery in and off it went again. Great, nice and smooth, a few loops good line tension etc, into inverted again rock steady, good line tension wings seemed level, recover from inverted (Half outside loop) and disaster, it got just past the vertical and turned in on me, went over my head about 40ft up in a graceful arc and ploughed into the circle behind me.

It had engine offset, rudder offset, tip weight (Set up using the method of lines on the reel half way up the inboard wing and an empty reel on the other wing took 3/4 oz, which was a bit more than the 1/4oz suggested in the instructions). Only change to the kit was to lengthen the nose by 1 1/2in to accommodate the battery without hacking into the wing and an adjustable lead out guide.  Line tension was good and steady right up to where it all went belly up, I'm sure nothing broke in flight but I'm at a loss as to what would cause this, Are there forces acting on the model during the recovery which point to a trim issue? Lines to far forward? Back? Still not enough tip weight, or do I just put it down to experience. I'm sitting staring at the remains thinking it deserves another chance but really would like to know if someone can help me not repeat  the performance if I do rebuild it.

Thanks in advance

TTFN
John.

Hi Mark,
 The CG was set exactly as per the instructions (1/2" behind the spar). I guess this in theory makes it slightly tail heavy assuming an IC version will have several oz of fuel added prior to the flight. The lead outs were/are set with the front line (Down) 1/4"behind the cg (So running slightly rearwards from the bellcrank end. It's a standard Brodak adjuster so the rear lead out (Up) was angled forwards from the bellcrank. The Tip weight was set with everything installed (Battery etc) and the whole thing hung from the leadouts with a slightly nose down attitude.

Weather conditions were almost flat calm and what (Very) little wind there was came from behind me. I'm not accurate enough to fly though my own prop wash just yet (Plus it was well off the previous laps flight line when it all went wrong), so I don't think that was the cause. But someone else's Prop wash?? I pieced the flight together and I wonder..... Our circles sit about 30yds off to the side of the end of the runway of a private flying club, A fair amount of interesting home builts etc frequent the field and the brief is if a plane lands or takes off cease all manoeuvres and fly level laps. (Sounds scary but works well). This happened to me during the inverted part, so I had to fly 6-7 more laps inverted than I had planned while a Christen Eagle took off. Given the conditions could his prop wash have been the cause? I didn't "feel" anything untoward after he cleared the field... Probably clutching at straws...... 

Having calmed down somewhat and remembering Phil Brown's Sig "SAVE ALL THE PIECES" my dining room table currently looks like a scene from an episode of "Air Crash Investigations" It's not as bad as I feared, Fuselage split, some damage to the foam wing Battery totalled. It was a fairly respectable 41oz so I think even with some weight gain as a result of the repairs it should not be a hangar queen so the rebuild starts this weekend. 

TTFN
John.

I agree with Winn. Either it was bad turbulence of something broke off in the plane that caused the inward yaw.