A review of configuration design for distributed propulsion transitioning VTOL aircraft

One of the biggest challenges in aviation is the design of transitioning vertical take-off and landing (VTOL) aircraft. Thrust-borne flight implies a higher mass fraction of the propulsion system, as well as much increased energy consumption in the take-off and landing phases. A good VTOL design will offset this disadvantage by transitioning to conventional forward flight, thus travelling at much higher efficiency than a comparable rotorcraft, for an overall improvement in mission performance. This paper intents to support the configuration designer of VTOL aircraft by giving a review of some of the available configuration possibilities, considering the latest advancements in technology. While VTOL aircraft can use the conventional wing-fuselage-stabilizer configuration, much of new development efforts involve unconventional planforms. The advent of distributed propulsion and electric- or hybrid-electric propulsion systems offers additional opportunities to optimize the vehicle layout and improve flight performance. This review considers propeller driven designs, lift fans and ducted fans, as well as jet lift and hybrid configurations that use a mix of propulsion methods.