Sal, that should be no big deal, I dare saying that this time. I'm quite confident that the original was well thought out and the geometrically equal (just smaller) model will fly well. The big elevator should be able to balance the model. I just can't prove that since both my stability calculator and the simulator simply assume a nice "round" wing airfoil polar, a symmetric stab airfoil, and positive stability. I can somewhat circumvent them but not completely.
But negative stability is basically rendered, as the simulator flights show. That's why the simulator model now takes off easily after I made the tailskid higher. The model picks up speed until the tail raises automatically and takeoff occurs. It's quite surprising to see that, and it's good.
Several things are counterintuitive on IM, but only because we're not used to it. The airplane seems even quite good-natured as long as the normal flight envelope is observed. If you fail to do that it's a beast, though. So finding a good balance may not really be a problem but you might rather have a hard time getting used to the things that are counterintuitive in the first place. After that (programming the flight computer between the ears) flying the IM should be easy.
You could use the simulator model - even if it's crude - to practise. You should set up the real model to assist you in any case.
I would set different elevator throws up and down, maybe by dual rate. Up should be small (10° or less) to avoid stall, down should be big (25°) to balance the airplane.
Permanently pushing the elevator stick (when the airplane is not yet balanced) is cumbersome, hence a pitch hold gyro. Takeoff (raising the tail) might be tricky, both with unbalanced and balanced airplane, so I think about switching it on only after takeoff (and maybe before landing as well).
Adverse yaw is big but easily balanced by rudder. Now top aileron required even in standard turns is really big, and I feel a bit annoyed if the aileron-rudder mix is on and the rate of turn seems to be diminished by top aileron. It feels better if the airplane is banked with the mixer on and top aileron held with mixer off, but switching the mixer is annoying as well. In the simulator, working the rudder by hand is the best solution, but in reality it's rather a bank-hold gyro.
Maybe just for the record, there's another idea, not by me but by Blaine Beron-Rawdon whose stability calculator I'm using. He suggested a
rate gyro to stabilize a thermal glider in circling (
http://envisiondesignusa.com/evdusa/...mentation.html, mind the title). Interestingly, a two-channel (aileron) gyro is put on the airplane's
yaw axis so top aileron is about proportional to rate of turn. By adjusting gyro gain, different bank angles and rates of turn can be established. If the gyro axis is inclined 30° backwards (like in my glider, next three pictures:
http://time.hs-augsburg.de/~erd/Mode...ar.html#Fixtur) it will even make for some roll stabilization in straight flight. All this would be nice also for IM but it has to be set up / adjusted so I'd put the gyro on the roll axis and switch hold mode on for the first flights.
There are no such solutions for other "problems" like down elevator required in some situations, power needed in turns, minimum speed avoidance, and such. That would require a programmable flight computer but is a completely different department as well as FPV. I think only about means to make all, and especially the first flights safer.