stunthanger.com
Engine basics => Engine set up tips => Topic started by: Gary Anderson on June 10, 2008, 03:44:44 PM
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Hi guys,
What is the advantage of using three or four blade props? Is it just ground clearance, or better engine run, looks, there must be something good about using them, to many of the big boys use them. I have always set my land gear to use the size prop for the engine I'm using. (Most two blade props and spinners are usually a lot cheaper than the three blade set up.) I'm sure the question has been asked before, just don't know where to go to get the answer. I would appreciate your input, Gary
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It is basically clearance. A 2 blade prop has a higher efficiency than the equivalent thrust 3 or 4 blade (a 1-blade is best!). However with the power that modern PA engines bring, sometimes you can't fit as big a prop as you might want to use the power.
Look at the WW2 Corsair. Even with the 4 blade prop, they had to "bend" the wings to get extra prop clearance.
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Blade area to absorb H.P.
Less Dia. to reduce torque reaction.