HI, IAM BUILDING A BALSA USA EINDECKER 90 USING A SUPER TIGER 2 STROKE G90 WAS WONDERING HOW BIG A PROP I COULD USE I Want to use a wooden simatar size/ pitch

I would try a 16x6

APC 17 x 4 fun fly prop will work too. That thing should fly SLOWLY.

Hi!
16x4W APC !
16x6 is a little to big but might work too. 17x4 ...well sounds big to me!
I myself use a 16x4W APC on my You-Can-Do .60 (MVVS .91). Best prop for that plane /engine!

A 14 x 6 is the normal optimum prop - you could go to a 15 x 5 or a 16 x 4 -

I use a 13x8 with mine on an Ultra Stick. It winds up fast and gives me good speed at 12k rpm. For your plane I'd expect a 6 pitch would give you the right speed, so maybe a 14x6 would work well?