System-level assessment of tail-mounted propellers for regional aircraft

Three regional transport aircraft of different configuration are synthesized for the same design specification using an automated design routine. The first aircraft features wing-mounted propellers, the second aircraft features propellers mounted on the horizontal tail plane, while the last configuration replaces the horizontal and vertical tail with two ducted propellers mounted near the rear of the fuselage. These last two innovative configurations have the potential to reduce the cabin noise, while the ducted propeller could also reduce community noise. The analysis and design methods to size and analyze these configurations include weight and balance, stability and control, aerodynamic performance, and mission performance. Propeller slipstream effects are taken into account and demonstrated to play an important role in the sizing of the horizontal tail surface. A comparison study between the three aircraft for a harmonic mission of 1530km and 7500kg payload demonstrates that the aircraft with wing-mounted propellers has the lowest maximum take-off mass and burns the least amount of fuel. The two innovative configurations have slightly less performance, which is ultimately attributed to the large center-of-gravity excursion that stems from an aft-mounted propulsion system. A 3% increase in maximum takeoff weight is predicted along with a fuel burn increase between 5% and 10% for the innovative configurations, respectively. Further investigation of the underlying assumptions might improve these results in future studies.