Built for horsepower, the .91 still uses the same case as the FA-65/80 but puts out a whopping 1.7 hp. Famed Radio Controlled Modeler columnist and engine guru Clarence Lee calls the .91S "a real stump puller...". Compared to popular competitors, the lightweight AAC 91S wins the power-to-weight ratio contest hands down. You will be astonished at the power, reliability and smoothness of this engine when you see it for yourself.
