Three-Engine Two-Fan Navy Multimission V/STOL Aircraft Considerations

A three-engine, two-fan arrangement for an advanced vertical and short takeoff and landing (V/STOL) lift/cruise multimission aircraft has many advantages.

With three engines, sufficient engine-out thrust is available for safe operation, over the range of multimission emergency landing requirements. The flexibility offered by being able to shut down one engine for loiter and cruise results in a fuel-conserving aircraft. The capability to add the power of the third engine provides a high-speed vehicle when the mission requires.

A two-fan system with fans under each wing provides for smooth transition from vertical flight to forward flight and return. Minimum-distance STOL performance is achievable because all of the thrust is available to accelerate the aircraft during the takeoff ground roll and to interact with the wing during climbout.. In shaft-driven systems, clutching horsepower can be drastically reduced or eliminated. Fans can be made interchangeable. Maximum fuselage volume is available for payload and operational systems components. Wing-mounted pod arrangements provide good compatibility with such passenger-carrying configurations as vertical onboard delivery (VOD) and commercial aircraft.