Rotary engines are known for their high power density, responsiveness to turbocharging, and mediocre fuel consumption. Modern commercial use has been limited to Mazda automobiles while some current UAS feature rotary engines in naturally aspirated gasoline configurations. In recent years, work to apply common rail direct injection to these engines has been completed enabling heavy fuel operation with fuel consumption characteristics below 0.50 lb/hp-hr. Several naturally aspirated rotary engines are commercially available in the 30-50 hp range, suitable for Group 3 UAS, while heavy fuel rotary engines in this output range are in development. Applying forced induction to these engines further improves UAS performance through altitude normalization. Baker Engineering LLC seeks to increase the power density of Group 3 and Group 4 rotary engines for the purpose of main propulsion in unmanned aerial systems. The Baker Heavy Fuel Rotary Engine and the R350 Rotary Engine each feature turbocharged heavy fuel operation and both are suitable for Group 3 propulsion. Characteristics pertaining to UAS performance shall be assessed for each of these engines. Potential Group 4 rotary engine propulsion will be investigated with evaluation of a turbocharged four rotor variant of the Mazda rotary engine family known as the 26B.
