HI ALL,
I need a participation in making a decision, between two brand new engines
Of the 80’s------OS.max 61 VF-------AND of the 90’s---OS.max 50 SX
Power output----1.8HP (17000 rpm)--------------------1.8HP (17000 rpm)
Prop size--------1X7------11X8------------------------11X7.7-----11X8
Weight-----------18.6 oz.------------------------------13.76 oz.
(The above data given by os.)

Now which one works better for a sport model 70 in wing span
(24 oz./sq.ft) wing loading, btw (both engines set ok. In the model)
If some one had actual tachometer. Reading for any of these engines, let us see it