Blade Tip Turbines
Systems with blade tip turbines can be considered a form of crosswind flight because the blade tip velocity is much greater than the wind velocity. We can capitalize on this phenomenon by using a turbine suspended below a lifter kite as suggested by Pierre.
Pierre’s blade tip turbines.pages (165.2 KB)
I would like to suggest the following improvements.
- Use two coaxial tip turbines at the end of each blade in order to neutralize cantilever forces and increase the available power. Tip turbines rotate at high speed and do not require gearing.
- Transfer the power from the tip turbines to a ground generator by means of a cable drive. This would eliminate the weight of an on-board generator, slip rings and an electrically conductive tether.
- Use the main rotor in auto gyro mode as an assist to the lifter kite to provide tension for the cable drive. This rotor is in line with the tether and operates at low efficiency due to cosine losses.
- In order to prevent the whole system from twisting the cable drive, use two counter rotating systems joined to a single cable drive but with two tethers connected to the lifter kite. This will prevent twisting, stabilize the lifter kite and double the power output.
Blade Tip Turbines.pdf.pages (178.4 KB)