Have now completed the punch list items and am ready to maiden in the next few days. Tedious but important things like checking and setting throws, establishing fore:aft and lateral balance, double checking connections, blue loctite, etc.
I do have a few disappointments
1. The linkages of servos to elevators really is not precise. I have used 1 1/4" servo arms with AW control horns; with the geometry of the linkage different side to side, I had worried that the throws of the elevator halves would not be equal. Guess what? they are not. I am getting about 10% more throw on the L half than the right. I will see how it flies, but i'm almost certain that there will be some roll coupling with the elevator. I may have to build some structure in her aft and mount the elevator servos properly.
2. She was an ounce out of balance laterally; had to add an ounce of weight to the L wingtip. That is not related to distribution of weight in the fuse, but must relate to balsa density, or glue or something else. It is not that big a deal to fix, as the wingtip has ample solid balsa. See pics.
On the positive side, i am really impressed with the DLE55RA. It drew fuel and fired choked with 3 flips, and started and ran with three more. The fuel tank holds, I am estimating, 40oz, so one has the possibility of long run times.
After 15-20 min of idle -> midrange -> idle and a small mount of LS and HS needle adjustment, the engine ran WOT at 6500rpm. By the end of the tank (about an hour run time altogether), she turned 6750-6800 with a Xoar 22x10 beech prop. With that setup, i measured 27#8oz of thrust, so i have a T/W now of almost 1.5:1, which may get better with time. The engine runs smoothly, and even brand new would idle reliably at 1700rpm. Broken in, it will probably idle down to 1550 or 1600 like the DLE55 will.
My well-broken in DLE55 engines only turn 6800-6830 on the ground with the same prop, so I think the 55RA may well be good for the advertised 100 extra rpm.
We are all interested in flight reports from anyone else who has gotten their R90 into the air.