This is the YS 91SRX-Tareq Side Exhaust Helicopter Engine. Developed in collaboration with Tareq Alsaadi, the 91SRX-Tareq was designed for demanding 3D pilots. Featuring the latest in YS helicopter engine technology, the 91SRX-Tareq includes a redesigned carburetor, combined with a redesigned piston and sleeve and a lightweight machined heat sink, creating the most powerful and responsive .91 engine in the YS line up.
Type: 2-stroke helicopter engine
Displacement: 0.91 cu. in. (14.89 cc)
Bore: 1.06 in (27.0mm)
Stroke: 1.02 in (26.0mm)
Total Weight: 19.9 oz (565 g)
RPM Range: 2,000–17,000