The number of blades on a propellor

[bizerta]

My father's Cessna 182 had a 2-bladed prop. I can remember many Beechcraft had 3-bladed props., a DC-6 had 4-bladed props, and recently, a E-2 Hawkeye has an 8-bladed prop. What's the advantage to more blades? I would think the engine's power would be converted to motion regardless of the blade count.

The only things I can think of are:
=== ground clearance; more blades = shorter blades
=== lighter blades; with more blades, each blades needs to support less, but the mass of 8 blades would outweigh the strenghening of four blades.

And as a side note: does/did anyone make a 5, 6, or other blades prop?

[Alessan]

Originally Posted by bizerta

And as a side note: does/did anyone make a 5, 6, or other blades prop?

I don't know about fixed-wing aircraft, but several helicopters - such as the CH-53 - have six-blade props.

[jz78817]

Originally Posted by bizerta

My father's Cessna 182 had a 2-bladed prop. I can remember many Beechcraft had 3-bladed props., a DC-6 had 4-bladed props, and recently, a E-2 Hawkeye has an 8-bladed prop. What's the advantage to more blades? I would think the engine's power would be converted to motion regardless of the blade count

well, one thing to keep in mind is that props have a maximum rpm; once the tips of the prop blades reach the speed of sound, efficiency drops off sharply. More blades can get you more thrust for a given prop diameter.

[Francis Vaughan]

Bit of a favourite this one.

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[Xema]

Originally Posted by bizerta

does/did anyone make a 5, 6, or other blades prop?

Single blade
5 blades (scroll down)
6 blades

[Xema]

7 blade prop

[kanicbird]

From some work I did from boat (well really unmanned sub's) props:
1 blade is the most efficient but unbalanced and impractical.
2 blades is the most practical efficient setup
Adding more blades and you can balance them but the efficiency decreases (due to the blades interfering with the flow pattern of each other), but the ability to transmit power increases.