Advanced Concepts
V/STOL (Vertical/Short Takeoff and Landing)
There are several ways to go straight up and end up flying, though the
means of doing so is usually much heavier and less economical than doing one or
the other exclusively. The Harrier and the Osprey (both, incidentally, named
for birds of prey) are really the first generation of operational systems for
VTOL. There will be others. A system is planned for the upcoming Joint
Strike Fighter which will likely have a turbofan/shaft engine, driving another
fan part-time to generate lift thrust.
Propfans
The propfan bridges the gap between the turboprop and turbofan. Turbines
power large, short span, wide chord fans without a duct around them.
Performance is somewhere between a turboprop and a turbofan. As yet,
the propfan's economy has yet to outweigh the noise problems and
lower operating speed.
Advanced Turbofan Concepts
Ramjets : Information Page
