aircraft propeller as wind turbine blades?

[isee]

Would a fixed pitch prop work as well, better or worse than a similar sized diy pvc or wooden blade? I am about to make a wind turbine for fun and might have access to some props from a Cessna or the like. Would that be a worthwhile alternative to making my own? Would a two blade work, or should I look for a three blade?

It will be mounted on a dc permanent magnet motor (220v, 5300rpm, 8amp, 1.1kw) in  an area with an average wind speed of 9.2mph, pretty evenly distributed throughout the year.

[MattM]

I'm guessing not so well, but if it's free

[midwoud1]

Hi Isee.

How much is the Cesna prop diam.? We need 3 meter diam. for 800 Watt.

Rgds  FBM.

[karvik]

Hello!

Plane prop has a profile on the wrong side.

[mab]

it would definitely be worse than even a half decent carved wooden blade set:-

if mounted facing the wind (like on an aeroplane) then the curved side of the aerofoils would be facing the wind and would be like flying a plane upside down - it would work but be very inefficient.

if mounted the other way then it would turn backwards (i.e. the sharp trailing-edge of the blade would become the leading edge and the rounded edge would become the trailing edge, and would be equivalent to flying a plane backwards - again very inefficient - I've never managed to fly a plane backwards (except for a few feet in a tail-slide before it flipped round the other way) so I don't know just how inefficient it would be, but for your windmill I suspect you'd be better off with a couple of planks of wood.

I guess that's kind of a long-winded way of saying what Karvik just said - but I've already typed this. 

BUT: if it happens to be a variable-pitch prop (?) and you can adjust for -ve pitch then you may be on to a winner.

[stofanel]

I would venture to guess that an airplane prop would produce slightly better performance than an amateurishly carved wooden blade. First of all, propeller airfoils tend to operate at very high Re regimes (>2M) and transonic Mach numbers (the tips of these propellers approach Mach 1). Small wind turbine operate at low Re (<200k) in incompressible flow (M<<1). But even if they had the right airfoils, propeller blades are twisted differently. Propellers are designed to produce suction in front of the actuator disk, while windmills will produce suction behind the actuator disk. Sure, one can freemill a propeller to produce some power, but the efficiency will be horrendous.

[Royalwdg]

Airplane prop are built to push air and our wind turbine blades are built to be impelled to move by the wind like an airplane wing.  Props will not work.

[midwoud1]

Aircraft propellers don't work on windgenerators , Airfoil in the wrong direction. Wrong pitch. Heavy weight.
They are designed for 2400 Rpm. Small diams.
Read Piggott and Dan's Books.

FBM

[Flux]

The aeroplane prop is a poor choice for the reasons already given. In addition it is likely to be too coarse a pitch and far too heavy for what I suspect is a treadmill motor. The gyroscopic forces will tax the shaft and bearings to the limit.

A 3 blade carved wooden prop will get you some results from that motor but 800W is way beyond any continuous rating.

Flux

[isee]

Thanks all, I had a closer look even at a smaller wooden prop (2ft blade) and you are all indeed correct. Far too heavy, narrow and with the leading edge on the wrong side. Was just an idea, glad I checked.