JM Harwood’s current efforts are focused on a bolt-in, heavy fuel replacement for the 6 hp 3W-56 gasoline engine used in the g-MAV / Class I. JM Harwood is currently using a Modified-Off-The-Shelf (MOTS) 3W-56 engine as a test bed for the development of critical technology such as the V-SInTech direct fuel injection system. This technology will flow into JM Harwood’s prototype XO-3 heavy fuel engine. The expected power-to-weight will exceed 1 hp / lbm and the specific fuel consumption will be approximately 0.5 lbm/ hp–hr.