In 1967 the US Air Force solicited proposals for ``low-disc-loading [Vertical Takeoff and Landing] configurations suitable for high speed flight.' Bell Helicopter elected to respond with a proposal after initial analysis on configurations including a stopped edgewise disc and a trail rotor. They concluded that a folding proprotor design would best meet the requirements laid forth. Initial analysis work began on this folding proprotor (stop-fold) design in the same year and concluded in 1972 with a full scale 25 foot diameter pylon and rotor assembly wind tunnel test at the NASA-Ames Large Scale Wind Tunnel. The project was concluded at this point and never resulted in a production or research aircraft.
The original proposed stop-fold tiltrotor design by Bell Helicopter allowed for vertical takeoff and landing, a transition sequence rotating the pylon rotor assembly from helicopter to airplane mode, a conversion sequence during which the rotor stopped and blades folded along the pylon, and a transition from prop thrust to auxiliary jet engine power while the rotor was being stopped. This configuration effectively removes the high-speed restraints typical of a prop-driven aircraft and instead opens a flight envelope comparable to a fixed-wing jet.
This project entails both the simulation and basic analysis of the stop-fold concept with special attention to frequency responses and potential coupling between modes.
| Identifer | oai:union.ndltd.org:GATECH/oai:smartech.gatech.edu:1853/29662 |
| Date | 09 July 2009 |
| Creators | Bosworth, Jeff |
| Publisher | Georgia Institute of Technology |
| Source Sets | Georgia Tech Electronic Thesis and Dissertation Archive |
| Detected Language | English |
| Type | Thesis |
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