Could someone tell if the O.S 30 FS is the equivalent to the O.S .15 2 stroke, are there any simple conversion charts.

Thanks John

I don't know if there are any charts but in the past we always said " take 10 off and it should be good ". If it's a 30 4s then it should work fine in a 20 size plane. ENJOY !!! RED

Thanks Red

I'm thinking of putting a .15 2S or 30 4S on a E Flite PT-17 , it has a 44" wing

John

Red Head is right in this size,
typically
4-stroke minus about 33% = 2 stroke

like
40 4c = 25 2c
70 4c = 45 2c
90 4c = 60 2c
120 4c = 90 2c
etc.etc.

Thanks Man !!