I crashed bigtime yesterday and I am not exactly sure what went wrong. The plane is a Great Planes Big Stik 40 with an OS 55 AX. This was a brand new plane on its third flight. It weighed 5lbs 4.5oz. The balance point was 90mm. with an allowed range of 82-102 mm. Just slightly nose heavy; should be ideal for a beginner. The transmitter is a JR7202. The throws were Aileron +.35 inches - .2 inches; Elevator +0.63 inches -0.46 inches; Rudder +/- 0.75 inches. Exponential was set up at 20% all three. The recommended low rate was Aileron +/-.625; Elevator +/-.75; Rudder +/-1.25. The much lower throw on the Aileron was because I had problems with the aileron being too sensitive on my 1st Big Stik 40. The aileron differential was to cure slow turning difficulties I had with the 1st one. The elevator differential was set up because of too sensitive down elevator on the previous plane. I was trying to set the plane up like a trainor based on my experience with a World Models Sky Raider Mach I.
An instructor flew the plane once and with a few clicks of trim said it was fine. The second flite was mine and I took off very well, the aileron sensitivity was light, very easy to fly, aileron turns were good without rudder, had a little difficulty maintaining altitude; sometimes too high; sometimes too low. On the approach to landing, I decided the plane was too high when abreast of me (About 4 feet AGL ) and I started a go around. A little situational awareness is needed to describe what happened next. We were facing North; the plane was landing West to East. The wind was almost calm - very light. I went from idle to wide open and gave it a little up elevator. The plane very quickly rolled to the right; turned right; flew over our heads to the South. I somehow
managed a half loop to the North and then rolled upright. I then did two touch and go's; one good; one in the dirt but Ok; and
then landed a little hard in the dirt and broke the prop. A Zinger 13X5. Replaced the prop with a MAS 13X6. I was probably
elated because the plane had survived my first flight with it and I had evaded a close call. So I did not try to analyze the close
call - big mistake. Fueled up took a break to relax. Took off. I should mention both take offs were by gradually easing on the throttle and there was a slight turn to the right; easily corrected by even a beginner. Did a few circuits waiting for traffic to clear;
and then started to land. Again was too high and started to go around at about 4 ft. AGL. Again full throttle and a little up elevator. Again a roll to the right and over our heads. Managed to get the plane headed North, but in a knife edge, with the left
wing low and it plowed into the ground. I have firgured out that it was very wrong to go to wide open throttle as half to 75%
would have been adequate. We had just carefully set up the engine before flying and there was no hesitation, whatsoever,
quickly going to full throttle from idle. The plane maintained altitude at 40% throttle. Although not measured; the thrust to weight
ratio was probably over one for both propellers. I need to understand what exactly happened so I can avoid these situations
in the future. I have found a lot of different ways to crash and I am getting discouraged.