Prop blade loads
Prop blade loads
(OP)
Hi!
I'm trying to design a variable pitch mechanism for a 2-blade prop (D 1.75 m) and a 160 HP engine. The pitch mechanism should be actuated by a DC motor. Trouble is, I don't know how to calculate the aerodynamic loads which twist the blade. Best result I got so far is around 60 Nm, but I think that's to high.
I need a book suggestion or a formula or any data I can use to estimate the DC motor power,gear ratios etc..
I'm trying to design a variable pitch mechanism for a 2-blade prop (D 1.75 m) and a 160 HP engine. The pitch mechanism should be actuated by a DC motor. Trouble is, I don't know how to calculate the aerodynamic loads which twist the blade. Best result I got so far is around 60 Nm, but I think that's to high.
I need a book suggestion or a formula or any data I can use to estimate the DC motor power,gear ratios etc..





RE: Prop blade loads
First, do the problem twice. Once with the blade at angle "A" and then with the blade at angle "B". The difference in forces should give you a way to estimate the torque required.
Fe
RE: Prop blade loads
Cheers
Greg Locock
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RE: Prop blade loads
Don´t forget the centrifugal loads trying to fine-pitch the blades (unless you use counterweights).
RE: Prop blade loads
good luck
RE: Prop blade loads
RE: Prop blade loads
I had a motor glider in my shop with a variable pitch/feathering prop made in Germany. In an accident a blade tip had been damaged.
It was sent to a repair station and serviced.
When the aircraft was test flown, the prop would not feather, several attempts, were made which produced ominous noises from the feathering mechanism. At this point the test flight was dis-continued, the aircraft landed, and the propeller checked. The feathering mechanism was bent.
We then discovered that the repair station had installed the counterweights on the wrong side of the prop.
B.E.
RE: Prop blade loads
http://www.vintagebonanza.com/docs/215-manual.pdf