Nick, Cran, Dave J et al,
What's the typical magnitude of hover efficiency gained by adopting 'washout' in a blade as opposed to a non-twisted blade.
It's a loaded question as the Rotorway needs all the 'lifting' help it can get and I was wondering whether a more efficient, twisted blade design would be a relatively inexpensive performance enhancement.
As it stands, the Rotorway autorotates extremely well with plenty of time to get the lever down and RRPM recovery easy. It might be worth sacrificing some of this for improved hover performance which, lets face it, is where most of these helicopters spend most of their time.
Could the required twist be provided dynamically by a fixed outboard tab on the existing blade (Aluminium extrusion leading edge with bonded/rivetted skins) or could you see structural / stress-related difficulties in such an application.
The current method for fine tuning the tracking is to bend the trailing by a few thou'. Therefore, I suppose simple blade twist could be established by bending the trailing edge to achieve reflex at the tip and downwards towards the root......
Your thoughts would be appreciated.
J