Hi!
Tettra tanks are very common in the racing world. There is many other dimensions.
Smallest is a 85cc (3 1/2 oz) and largest 500cc tank.
The China-Clipper tough to fly...?? No no. It's a sweet flying thing
!
Al these sport Q-500 racers, if set up correctly, are as easy to fly as highwinged trainers and could be flown as slow as these too. Al my Q-500 airplanes could be flown to a nearly stand still in the air without stalling. Of course they are capable to stall but only when I want too, by giving full elevator and aileron (snap-roll).
Have you balanced yours laterally? Perhaps one wing is heavier than the other? I've always had to put a little lead in one wingtip on mine.
Also check final weight. 1800g is what my planes weigh (due to Swedish Q-500 rules) but American Q-500 rules allow even lighter airplanes at 1360g (3 1/2 pounds).
The landing gear on the Sonic 500 is not good, too soft! But bend them forward and landings will be easier.
Regards!
Jan K
Sweden