RE: Aircraft for an OS 91 4-stroke
I have a OS 91 Surpass in my Tiger 60 and love it *( both plane and engine). The previous motor was a MVVS 61 on a tuned pipe and power is comparable, but not as finicky as the MVVS. The Tiger is aerobatic but not really a 3d'er.
That's what my Goldberg Sukoi 26MX with a saito 1.80 is all about!
Mike