Consideration of the High Bypass Ratio Tip Turbine Cruise Fan for Long Range and Long Endurance Aircraft

Consideration of the high bypass ratio, tip turbine cruise fan for long range and long endurance aircraft is presented. Thermodynamic analysis and installation aerodynamic criteria are discussed. The analysis includes a comparison of the turbojet, low bypass turbofan, and high bypass cruise fan systems with the same gas generator cycle. Significant test program accomplishments on the cruise fan system are presented, as well as suggested aircraft installations. The tip turbine cruise fan is shown to have unique multiple bypass ratio characteristics with high take-off thrust ratings, low specific fuel consumption levels, and high speed potential.