The PRO series helicopter ring-type engines are equipped with dual ball-bearings, Schnuerle porting, one ring-type piston / cylinder assembly and two-needles automatic mixture control carburetor.

Specifications:
-Displacement: 8.27 cc. / 0.504 cu. in.
-Bore: 22.5 mm. / 0.886 in.
-Stroke: 20.8 mm. / 0.819 in.
-Crankshaft: UNC 1/4 - 28 Practical
-RPM: 2,000 ~ 20,000
-Output: 1.75 BHP / 17,000 RPM
-Weight: 405 g. Iwo/muffler / 14.28 oz.