I want to design & build my own gyrocopter and started to read a lot about it. The intention is to make a 2-seater Microlight (450 kilo max take-off weight). My most important concern at the moment are the rotor blades.
Two main questions here:
A. Theory regarding gyrocopter rotor blade.
What is the theoretical optimum shape?
I see many companies offering many types of rotor blades from different materials. Just from pure theoretical perspective:
(1) what is the ideal form for a gyrocopter rotor blade (shape, angle of attack twist, etceteras)? Since the outer part of the blade produces the lift and the inner part maintains the autogyro effect (depending on circumstances such as forward speed) I can imagine that theoretical optimal shape is something highly complex for a gyrocopter rotor blade. Does anybody have any idea from practical experience or theoretical background?B. Tilt (or bend) the rotor blade to save space.
(2) Are there rotor blade manufacturing companies who go for the best shape/ best performance? Who either have the theoretical background or practical test facilities. Any suggestions which companies to contact?
Also from what I read so far I would need rotor blades of about 365 cm each, which will make the vehicle too long to handle (won't fit in my garage for sure).
My friend has a model helicopter where the rotor blades can be folded together (both blades side-by-side in parallel), which reduces the space problem already.
Due to the centrifugal forces the blades stretch out by themselves without a permanent fixation (they hinge 'freely' around a single pin).
(1) Could the same trick be used on a large (real-life) scale for a gyrocopter? Does anyone have any experience with this?Closed (bend/ folded) rotor blade.
(2) I know naval helicopters can also bend (or fold) a single rotor blade in half, which conciderably saves a lot of space. Can I use the same technique for a gyrocopter rotor blade? Anyone knows if this has been done before? Does anybody know a rotor blade manufacturer who could produce such a blade?
Open rotor blade.