Mart,
APT is developing the OPOC engine for FEV Engine Technologies, so
FEV’s website might provide some additional insight into the type of supporting tech you'll see going into the powerplant. As if the OPOC design, the converted 4cyl & 6cyl Subaru boxer engines and Pratt’s PW207 turbine weren’t enough engines for one program, there is a fourth manufacturer developing a 6-cyl diesel for the Hummingbird:
Nivek R&D.
Re: Comanche, as IFMU states the rotor system was designed around a composite flexbeam which allowed all but the thrust bearings to be eliminated. Pitch control rods
were retained. IIRC, the offset hinge was 15%.
Slowrotor,
Can’t answer whether or not the A160 uses heavy tip weights. I know the team
has emphasized the fact that the tip of the rotor is more flexible than the root in terms of flap, lag and torsion.
With regards to the rotor head, everything about this vehicle has been specifically designed to meet very exacting long-endurance goals, so lower drag was traded-off wherever possible. Airflow interference with the mast-mounted mission pod probably also influenced the numbers. As Dave Jackson notes, it’s a very mission-specific design.
Another supporting technology publicly revealed by the DoD is the use of “high-speed electrical actuators [which, in combination with the hingeless rotor] allows for precision control and improved performance in turbulent flight conditions.”
I/C