While the 6 hp XO-3 is currently JM Harwood’s primary focus for heavy fuel engine development, larger and more fuel efficient engines are being developed.
XO-36 Heavy Fuel Engine
The XO-36 is an experimental opposed cylinder (XO) 36 cubic inch heavy fuel UAV engine. This is JM Harwood’s 60 hp UAV heavy fuel engine (HFE) with power-to-weight exceeding 1 hp/lb and Specific Fuel Consumption (SFC) approaching 0.5 lb/hp-hr. This engine is intended as a technology demonstrator for a Shadow C sized UAV engine. It is geometrically similar to the XO-3 engine and leverages the lessons learned in the heavy fuel combustion test bed.
TC XO-48/4S Heavy Fuel Engine
The TC XO-48/4S is a 60 hp turbo-charged (TC) 48 cubic inch 4-stroke (4S) heavy fuel engine intended for endurance UAV applications where minimizing fuel consumption is more important than minimizing engine weight. It has a specific fuel consumption of approximately 0.4 lb/hp-hr and a power-to-weight approaching 0.7 hp/lb. It traces it roots back to the foundation of JM Harwood. Prior to Summer of 2009, JM Harwood engine development was focused on high performance, high compression 4-stroke engines.