Indeed my blades rotated by their trailing edge! But they were small (0.23 m diameter) and rather “flat” and the efficiency of the fly-gen kite wind turbine using these blades looked to be nice, although this way is unorthodox and likely not recommended for larger blades.
Some previous discussion about this subject:
Yes, but the propeller has such a thin profile it still has incredible performance.
If it performed any better, we’d have more generator burnout issues.
This comes up now and then.
My thinking is:
A blade for a propeller is made to generate thrust. The curved side of the airfoil should face in the direction you want the resulting force to pull.
A blade for a wind turbine should spin with an approaching wind and generate a lift force mostly downwind and a little bit to generate a moment to rotate the shaft. The curved side of the airfoil is facing away from where the wind comes from.
Propellers come in CW and CCW types, but no matter how you …
I measured (with a multi-meter) 9 volts at 13.7 m/s then 3 amperes at 14.4 m/s, by using a Master Airscrew GF 9x4 on a motor Mabuchi RS-380PH used as generator, at about 7100 rpm, so 85 m/s tip speed and TSR of 6 for an apparent wind of 14 m/s. I extrapolated the 7100 rpm value from the voltage (3.8 volts) obtained with a drill running at 3000 rpm, which is of course very approximate. The apparent wind speed by car was measured with an anemometer.
So about an average of 27 W at 14 m/s, for a sw…
Hello Pierre:
You can get away with running small, thin-profile, injection-molded, toy propellers backwards.
A propeller of normal thickness is terrible when running backwards as a turbine rotor.
I once did a serious, documented, experimental project to develop a wind turbine rotor that could work in either direction for a non-aiming turbine in a bi-directional wind resource. Talked an architectural firm into paying for it. Tried a few versions. Turned out not to work very well - unaccept…
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