# The number of blades on a propellor **URL:** \ **Category:** Factual Questions\ **Created:** [July 4, 2012, 11:05am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204 "2012-07-04T11:05:35Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![bizerta](https://avatars.discourse-cdn.com/v4/letter/b/3be4f8/32.png) [@bizerta](https://boards.straightdope.com/u/bizerta)\ **Post date:** [July 4, 2012, 11:05am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/1 "2012-07-04T11:05:35Z")
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? ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [July 4, 2012, 11:43am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/2 "2012-07-04T11:43:07Z")
> [@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. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [July 4, 2012, 11:56am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/3 "2012-07-04T11:56:53Z")
> [@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. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [July 4, 2012, 12:02pm UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/4 "2012-07-04T12:02:34Z")
Bit of a favourite this one. [old thread 1](http://boards.straightdope.com/sdmb/showthread.php?t=234828) [old thread 2](http://boards.straightdope.com/sdmb/showthread.php?t=277540) [old thread 3](http://boards.straightdope.com/sdmb/showthread.php?t=626664) [old thread 4](http://boards.straightdope.com/sdmb/showthread.php?t=493444) ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [July 5, 2012, 3:02am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/5 "2012-07-05T03:02:26Z")
> [@bizerta](#): > > does/did anyone make a 5, 6, or other blades prop? [Single blade](http://www.glidingmagazine.com/Images/PropellerPylon01.jpg) [5 blades](http://www.mt-propeller.com/en/entw/news.htm) (scroll down) [6 blades](http://www.shutterstock.com/pic-47540671/stock-photo--bladed-propeller-of-military-turboprop-cargo-airplane.html) ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [July 5, 2012, 4:19am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/6 "2012-07-05T04:19:16Z")
[7 blade prop](http://t2.gstatic.com/images?q=tbn:ANd9GcTDEQftiFn18APX8257qT0N54E0n_W5BQwFdCHPZIq1qiHCtPZdsiHPCks4) ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [July 6, 2012, 12:36am UTC](https://boards.straightdope.com/t/the-number-of-blades-on-a-propellor/627204/7 "2012-07-06T00:36:55Z")
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.