Well, I did four test flights of the X-37 today. I had finished the fuse covers and just left the top of the nose with taped on pieces so I could adjust CG. I did a bunch of glide tests and had the CG pretty well bracketed.
We had a cold but relatively clear morning so I decided to do some test flights before I did the finish work.
Results were not great, and were a bit strange.
I needed to add about 2.5 ounces for CG so auw was round 14 ounces. A bit more than my shuttle.
I did add some 1.25" wide strips to the wing TE to help with CG and lift area as a last minute addition.
1)boost was ok, I pitched over early to keep out of the fog, I tried to counter roll and keep the nose up, it was starting to react, but then stalled and snapped suddenly and landed inverted, I repaired the one broken stab with tape. It did not seem to want to react to pitch control, as if it was extremely nose heavy, but then suddenly snapped.
2)Added another half ounce of nose weight, since it snapped, thought maybe it was still a bit tail heavy. Boost was kept vertical, control was ok during boost, clicked in up trim for glide, maintained about a 30 degree nose down attitude and pitch up didn't seem to have any effect, no damage, landed at the same 30 degree down angle.
3) Feeling maybe it was too nose heavy since not enough pitch control(I was running a lot of throw on both rates), removed some weight and moved battery back, boost was ok, but it was definitely tail heavy, not much pitch reaction, another snap but landing was relatively flat.
4)Moved battery back forward, boost was ok, once burnout happened, I kept the speed up, no up trim, kept nose down about 20 degrees, however flare never happened, as if pitch control was not happening, no damage but landed hard, nose down.
So, my construction is pretty sturdy, and the tail controls were very robust to take the abuse and not slip, the rolled fuse cover worked great and the airframe took the abuse with zero damage.
Based on the flight response, it appears that under vertical boost, control is ok, however once in a slower speed angled decent, that the fuse flares at the rear, or the wing is sort of blanking the tail and the pitch control is not happening. Then eventually I get so much throw it pitches up suddenly (sort of like a speed break effect)and stalles and snaps, or never really pitches up.
It's interesting as Scott has gotten his to glide and found that it was very pitch sensitive. I am not running ailerons, however I didn't seem to have any roll issues, the plane stayed relatively flat and the snaps seemed to be under mainly pitch command when they happened.
I'm going to set this one aside for a bit and see if some suggestions here or eureka moment happens and go back to it.
