Added: 5 years ago
From: justinfluegel
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  • Can someone explain to me in a lucid and knowledgable way why some airplanes have three bladed props like the F4U Corsair and others have 4 like the P51 Mustang. The British Supermarine had 5 blades, if memory serves. I've asked the same question about electrical generating windmills. I'm still waiting for some egghead to explain.

  • (1)

    The job of the propeller is to transmit power from the engine to the air passing through the propeller disk. For efficiency, the propeller must be matched to the engine depending on the power of the engine.

  • (2)

    As engine power increases, there are limited propeller options to efficiently transfer the power:

    Increase the pitch of the propeller blades.

    Increase the propeller diameter (make the blades longer).

    Increase the revolutions per minute of the propeller.

    Increase the camber of the prop airfoil.

    Increase the chord (width) of the propeller blades.

    Increase the number of blades.

  • (3)

    Many of these options are impractical.

    Blade angle - the pitch of the blade optimizes efficiency; changing the angle, costs efficiency.

    Blade length - size constraints - landing gear must become longer, affecting structure & weight.

    Revolutions per minute - as blade tips travel faster they become supersonic - forming shock waves - increasing drag, costing efficiency.

    Airfoil camber - airfoils are chosen for efficiency, changing them costs efficiency & causes structural problems.

  • (4)

    This leaves increasing the blade chord & increasing the number of blades.

    Increasing the blade chord: Increases the solidity of the propeller disk. (Solidity is area of the propeller disk occupied by solid componenets (the blades) versus open area.) As solidity increases, so does efficiency. Although increasing the blade chord is an easy option, it decreases the aspect ratio of the blades, causing a loss of efficiency.

    Thus, increasing the number of blades is most efficient approach.

  • (5)

    As the power of engines increased over the years, engineers increased the number of propeller blades. Once they ran out of room on the propeller hub, they designed twin contra-rotating propellers on the same engine. Two such examples are the Russian Tu-95 bomber and Tu-114 airliner. They had some of the most powerful turboprop engines built and both feature a total of eight propeller blades per engine.

  • Thank you! Your explanation was lucid and knowledgable, written by someone with an engineering background. At slow wind speeds wouldn't four or five blades on a wind turbine work better than three?

    Also, I was told that the TU-95 made so much noise because of prop speed that a couple of planes in formation could be heard on both sides of the Black Sea. That's pretty loud, I'm not sure I believe that.

  • they retained the upper nose paint.

  • Why American warbirds like P-47 or P-51 have no camouflage? British and German fighters had always camouflage, but American didn't have... they were shiny with colour marks. Why??

  • Because of the weight issue,take the paint off its smoother and removes drag.

  • It also helps with identification. You dont want to shoot your own plane down

  • Later in the war, the USAF high command ordered the paint stripped off the fighters so that they could be seen. They wanted to attract attention so that the fighters could do there job. Later they stripped the bombers too since the camo paint was no longer needed.

    Stripping the paint also improved performance by removing a couple hundred pounds off the airframe.

  • because there so great that they don't need to hide

  • they were grey, to disguise against the sky. Germans also had color marks.

    ex. the squad leader would have a yellow nose

  • The correct reason that all these sofa historians are not telling you about is that by 1944 the skies over Europe began to run silent of enemy fighters. In an attempt to get german fighters to engage the Allied High Command for the US decided to remove the camouflage and go with a polished steel look. You notice this heavily on early war B-17's and late war B-17's.

  • the nose of the aircraft retained the flat olive drab to prevent the pilot from seeing a massive glare.

  • @justinfluegel It isn't polished steel, it's polished aluminum, and its beautiful.

  • Amazing !! Just Amazing !! BTW I wonder if the owners of these P-51s (or any war-birds) are allowed to have the functioning 50 cal guns in the wings!! Can they?? or do they ???

  • I agree beautiful air craft,and NO, they do´nt!

  • thats the second video with the same post of you...

  • no they dont allow you to have 50 cals

    to function on any retired war birds

  • i saw one that did. they were firing blanks when i saw it later it looked like it could take 50s it may have needed small mods though

  • nevermind optical allusions...

  • the f4u why does the prop turn counterclockwise then clockwise???

  • Wow... one of the few times Glacier Girl has actually ran! haha

  • I have stood in the prop-wash of a F4U and I can tell you it is an awsome experience!!!

  • I stood in the prop wash of a Cri Cri once. That was pretty intense, too.

  • Is thst Corsair from Planes of Fame?

  • francos

  • That Corsair looks like a F4U-1D model. There were no "G" models. The "G" associated with Corsairs designated aircraft built by Goodyear and were designated "FG" not F4.

    The 3 bladed prop, dual antennas and 6 50 cal guns limit the model possibilities to an F4U-1

  • thanks for the heads up... fixing now.

  • psh, i dont want to hear about japanese fighters, if they were so good then they wouldve dominated the skies. the P38, wildcat, P40 ruled the air over the pacific. The japanese planes were a suitable fight but when it came down to it they were pushovers. ill take a cadallac of the skies anyday than a mitsubishi zero

  • you got no clue XC0688....

    the zero wás way better than a f4u or a f6f. the japanese only got the lack of good pilots and workin weapons.

    the p38 got more firepower but less dogfight ability. the navy only won cause of the lack of good pilots in the japanese navy.

  • Dude, the F6F Hellcat ate Zeros for breakfast. Why do you think the Japanese ran out of good pilots? With a kill/loss ratio of 19:1 against the Zero I don't think anyone is going to make much of a case against the Hellcat in this comparison. The only advantage the zero had was turn, low speed turn at that, which by the age of the Hellcat was a defunct tactic. The only Japanese planes that compared were the Shindin and Hayate.

  • The kill ratio was that high for the F6F because by the time the Hellcat got into service pretty much all the good Japanese pilots were dead. Therefore giving the Hellcat the high kill/death ratio over the zero, because the Japanese had very few skilled pilots and the Americans had many.

    If the Japanese had some more skilled pilots the kill/death ratio would have been much different.

    Please, look up your information the next time you post something like that.

  • I have actually, and my comment still stands since even against the F4F Wildcat, a markedly inferior aircraft to the Hellcat, the Zero was only ever able to manage about a 1:1 kill/loss ratio. This was due to tactics, making best use of strengths, and best awareness of weaknesses.

  • American engineering understood that pilot safety takes priority. It never took much at all to down a Zero, while it took some considerable punishment to kill a Hellcat. The Hellcat's engine gave it 2000hp, while even later model Zeros only produced half that. Thus even though the Zero was lighter it was also much slower. The Zero couldn't dive to save its life either. So if you're attributing a 19:1 kill/loss ratio to bad pilots, then that's a pretty big insult to Japanese flight training.

  • ALSO, not only did the Zero suffer deficiencies in durability and top speed, once it reached its top speeds its elevator flaps got stuck because of the pressure. So not only can it not dive, but it was very difficult to pull out of the dive. It also rolled about as well as a square wheel.

  • I'm pretty sure we won cause of the big ass bomb we dropped on them..

  • lawl

  • lawl

  • There is just nothing like the sound of piston engined fighters! It's nice to see the three major fighter engines for the allies all starting up at one time (P&W R-2800, Allison V-1710, and the [Packard] Merlin).

    And the P-40 was an OKAY fighter. Any fighter with superior tactics stands a chance...but the P-40 filled a need when it was all the US had to offer.

  • the strength of the p40 was in a dive attack. she would reach supersonic and be able to pull out. the zeros couldn't. alot of zeros crashed because it was too light and not brawny enough to fly out of supersonic speeds.

  • i think ill start, no i wont, i think ill start, no i wont, yeah fine ill just start, oh no i think im gonna stall, no dont!, oh no i think i am!,no i wont stall!,yes i think im gonna stall!, no!, agh fuck this ill just flyyy **corsair talking**

  • but when it comes to best driven prop aircraft in WW2 it's got to be the P-51 or the Corsair. they had the speed, the range,the guns, an the moves lol.

  • and the looks ;-)

  • um ya I would rather be in a P-40 then a zero lol. an the P-40 wasn't that bad of a fighter. had armour plating unlike the Zero. zero had speed in it an the turning really. bad thign was it's machien guns had the hardest time during the earlyer part of the war shootign down p-40's cause the the protection it gave the pilot. really guys kind of hard to argue the p-40 to the zero. Flying Tigers should what good pilots could with a P-40

  • Gah! I can't stand it when the Corsair idles..It always looks like the engine's stalling!

  • The P-40 was competitive with a Zero just ask the flying tigers.

  • the best part is that a p-40 has NOTHING to do with any of this. Winning an argument online is like winning the special olympics, in the end, your still retarded.

  • Though not as capable as fighters *made later*, the P-40 was a rugged, dependable fighter; one of the best when the US entered WW2. George S. Welch, on December 7, 1941, downed 4 Japanese aircraft in his P-40. You're comparing apples and oranges; the P-40 was a *great* fighter for its time. Saying the P-40 was "the worst" is like saying "the P-51 was the worst U.S. fighter of the Korean War." Yeah, compare a P-51 to a MiG-17 and it's *going* to look bad.

  • edit out the intro

  • Nice but....I prefer the Spitfire and Hurricane

  • Really cool planes but my personal favourite is the bf109g10:)

  • these are cool planes but my favorite is the P-40 Warhawk

  • no offense, but the p-40 was one of the worst U.S fighters in ww2

  • No offense but the p-40 was an ok fighter. Wikipedia gives it a passing grade in the critical beginnings of the War. It could not match the P-51, but was a good reliable soldier.

  • The problems that plagued the p-40 plagued all u.s. fighters. The zero was fast and light and extremely tested inmanuverable at low altitudes and could out fly these planes. This is why the "Thatch weave" became a standard combat tatic. When a flying zero was captured off the Aluetians and repaired it was flight tested in San Deigo flight in to beter combat the zero.

  • the p-40m was hardly the worst fighter of ww2. just look at what the flying tigers of the american volunteer group in china did with them against the vastly superior japanese

  • thanks for posting video of our aircaft

    Provenance Fighter Sales...

  • F4U CORSAIR, CADILLAC OF THE SKY!!!!

  • Beautiful, yes. But, she seems cold blooded. Of course, if I was as old as she is, I'd be cold blooded to:)

  • beautiful planes

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