A Trade-off Study of Tilt Rotor Aircraft versus Helicopters Using VASCOMP 2 and HESCOMP

Trade-off studies were conducted wherein two versions of tilt rotor aircraft were examined to determine optimum mission distances where the tilt rotor designs were superior to a comparable contemporary (pure) helicopter. Two FORTRAN computer programs (VASCOMP II and HESCOMP) were used to predict aircraft performance. Program results were validated using data from independent sources. A simplified user's manual is included (with sample data and program output) for VASCOMP II. The experimental results substantiate that the V-22, designated to replace the CH-46F among other aircraft, will offer significant improvements in speed, loiter endurance, hover endurance, performance, and efficiency. The results lend further credence to the manufacturer's claims that tilt rotor aircraft can transport more passengers/payload over longer distances in less time than conventional helicopters while retaining the important advantage of vertical takeoff and landing. It is acknowledged that the tilt rotor can readily perform transport missions using less fuel than helicopters but if a large percentage of hovering flight is required, conventional rotary wing aircraft are far more efficient than a fuel consumption standpoint. However, they do not have the staying power that the tilt rotor demonstrates.