UMS Gas Radial Engine Manual 9-115 StandardMetric Type 4-Stroke Petrol SPARK IGNITION CYLINDER 9 (ABC TYPE) 9 (ABC TYPE) CAPACITY (CU. IN) 9.7 90CC Bore 0.98″ 25.1MM Stroke 1.02″ 26MM Thrust* 27.5lbf @ 24×10 Menz prop. 12.5kgf @ 24×10 Menz prop. Power (HP) 7.6 7.6 Rotation...