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Marshall_Stack said:Just wondering....
The P-47, F4U, and F6F all had the same radial engine. The P-47 had a four-bladed prop, the Corsair initialy had a large three bladed prop (then a 4 bladed), and the Hellcat had the "standard" three-bladed prop. The Hellcat was substantially slower than the P-47 and F4U. If the Hellcat was given a four-bladed prop would it been faster? I know that the F8F Bearcat was faster with a four blade prop, but it was also lighter (and I think it had an uprated engine).
What do you think?
FLYBOYJ said:3 or 4 bladed propellers are determined by engine efficiency (determined by engineers) - operating propeller pitch and length are also considered. If you go from a 3 blade to a 4 blade propeller, it doesn't mean increased performance and efficiency.
davparlr said:The original question is a good question. What were the engineering or programmatical design goals that caused the selection of a three bladed prop on F6F and the four bladed props for the F4U, et. al.? Did the F6F have a different optimum operating envelope? What caused the change to the F4U that would not help the F6F? Etc.
I don't know much theory behind propellers. I do note that most of the high performance German planes use three bladed props. These must not have been optimum since after the war, most high performance propellers were four bladed (A-1, B-50, most commercial liners, etc. although the B-36 had three bladed). The C-130 has gone to even more blades. Gotta be several graphs that must be optimized for the desired characteristics.
Electric props were at first very unreliable - electric current to the pitch changing mechanism's was run through brushes and a slinger disk - these used to fail and when that happened the prop would go to flat pitch - not good, especially on take off....syscom3 said:The availability of four bladed props in the early war years was an issue. The early Curtiss-Wright 4 bladers had electrically controlled props that had some serious reliability issues (B26's were crashing quite frequently because of this).
I dont think things really improved untill Hamilton-Standard perfected their four blade designs.
heheheh....syscom3 said:Ive heard that the 11th wonder of the world is to listen to an R2800 at full throttle and load, go into flat pitch with zero load.
I can vouch for that.... I've heard that same saying from the mouths of guys who heard it IRL....syscom3 said:Ive heard that the 11th wonder of the world is to listen to an R2800 at full throttle and load, go into flat pitch with zero load.
Marshall_Stack said:wmaxt and GregP, thanks for the info.
wmaxt, when I click on your link, I get a "page cannot be displayed" error.