O.S. FS-95V Ringed 4-Stroke Engine Review

Image Credit: O.S.

Review by Eric Bradley, Staff Contributor

Equipment Used:

- Mounted on TF Corsair and an AW Yak 54

- APC 13x6, 13x8, 14x8 props

- Xoar 13x6, 13x8 props

- Master Air Screw 14x6, 14x8

- Byron's 15% nitro with 15% oil


- More power than the .91FS SII previously made by OS

- Fits 60 size planes

- Carb position is far from the prop

- Easy to tune

- Multiple exhaust mounting options

- About $180 less than the .91


- NONE!  It is a great engine!


If you mount this on a warbird or a sport plane or a 3D worthy airframe you will not be disappointed. I tried various props all seemed to perform well. I use a larger prop for the motor on my Corsair and an APC 13x8 on this yak. At idle with bursts of throttle it sounds a bit like a Harley with a deep throaty exhaust. It started up with little effort on the first go, and extremely easy to tune and keep running. If you can afford to get one of these over a used .91FS it is so worth it. It's a flawless performer.