Originally Posted by
Ian Corrigible
Not quite true. Prior to the JHL effort being folded into the JFTL AoA (which included various fixed-wing STOL and V/STOL designs) in late 2010, the concept definition work had been narrowed down to three candidate configurations:
- Bell's QTR (with 55 ft diameter rotors)
- A conventional tiltrotor (CTR) that Bell had additionally been funded to study in parallel with QTR (with 80 ft diameter rotors)
- Karem's OSTR (specifically the TR75, with 75 ft diameter rotors). As you may recall, the Army's "representative" JHL configuration used for wargaming purposes from 2007 on – the High Efficiency Tilt Rotor (HETR) – was very reminiscent of the OSTR.
I/C
I mentioned the quad in parentheses as it was basically the only feasible solution that did not require the implementation of some very low TRL items.
TR75 relies on some very dubious tuning claims, in addition to extremely high risk, high frequency individual blade control.