Yeah ok that’s a good idea and would work for collective pitch testing. Would just have to limit the servo throws to a range it still has meaningful pitch so it doesn’t lose control, and then dial it in for optimum cruise.
I think the optimisation gain is mostly because of being able to have the best pitch in hover and in forward cruise, with forward cruise around 24m/s being a much steeper prop than what is required on the same motor whilst orientated for hover. With the tilt tricopter layout, we end up with a asymmetric drivetrain layout where the main 10" rotor (that doesn’t tilt) is producing some 60-70% of the lift in hover, whilst the two other tilt rotors (which also do yaw in hover) only do 15-20% of lift in hover each, and are essentially more for maintaining attitude control. That way with a fixed prop setup there’s some flexibility in that the forward tilt prop selection can be biased towards forward cruise, and the main rotor for hover, which then has to stop and stow for forward winged flight to reduce drag.
For the forward prop collective pitch version, the actual weighting needs to be determined in testing as using collective pitch might mean we can increase the bias to the main rotor in hover, if we can use reverse pitch on the forward tilt motors instead without it becoming unstable. (ie these would be used to “balance” on the main rotor) This wouldn’t be possible with a forward fixed prop at all as it wouldn’t have enough disk loading to maintain attitude control.
Also on the subject of determining optimum winged cruise, have you experimented, or have you done any tests to determine Carson’s velocity on winged airframes? (Ie best range is achieved at best glide slope speed)
A automated method for doing this would result in being able to determine the exact Carson’s velocity, and from that be able to accurately determine the required prop thrust and pitch requirements for each individual airframe, mass and configuration. Essentially this is like a airborne wind tunnel test using existing FC sensors onboard and some extra code (it can also be done manually). The simplest version without a AoA sensor would be to do a unpowered altitude hold test flight up to when it stalls ( and including stall if one wants to recover manually)
More information on Carson’s velocity can be found here: http://www.eaa1000.av.org/technicl/perfspds/perfspds.htm
And proposed methods for testing this with a FC here: http://diydrones.com/forum/topics/learning-and-using-lift-drag
I’m not sure if this might be partially implemented in the soaring additions, or might be helpful there as well to tune airframes for optimum endurance or range. (1.316 of Carsons being best endurance and 1.316 above Carsons velocity best range)