John
Very many thanks for your response.
I think the origin of the problem is that model aircraft/UAV pilots may only be interested in AoA at the touchdown point. I shall point out that Mr Chopper Test (SC) and Mr Hover Jet know better!
Since you have shown interest... manned aircraft tend to use an horizontal cylindrical or conical probe with parallel slots along but slightly either side of rotational axis. Is this just a simple drag balance device or do they measure pressure and servo drive to balance?
Obviously, it would be best to KISS for a small aircraft. On the principle of parsimony, we only really need to relay/record AoA at T/O, stall recovery and landing. If possible, I would like to go for a symmetrical aerofoil section and had thought of a section of model helicopter rotor blade. Any ideas on where to pivot it? Max thickness point, or max pressure point?