F4U Corsair Design Features

greetings this is Greg the f4u Corsair is probably the most easily recognized plane from World War two none of its external features are particularly unique the long nose inverted gull wings and the forward location of the vertical stabilizer can be found on other airplanes but no other airplane has all of these distinctive features and not to the same degree there are specific reasons for each of these things and there are quite a few other unusual features about the Corsair that a lot of people don't know about I plan to cover these subjects in this video I'll probably keep this video pretty light on technical issues since my previous airplane video and my next one will be very tech heavy I'll be focusing on the world war ii corsair variants mostly the earlier - ones but many of the pictures will be used for later variants externally they look almost the same so let's get started one unusual fact is that the f4u Corsair has aluminum armor in addition to its steel plate normally aluminum won't do much to stop a bullet unless it's too thick to be realistically used in an airplane but this wasn't normal aluminum it was an aluminum and copper alloy that was made with a special procedure making it very hard this alloy was invented by a German named Alfred Wilm in 1903 it was called duralumin or more often in u.s. technical manuals it was called der all the Germans didn't keep this new discovery a secret why would they nobody was taking the idea of military airplanes seriously in 1903 but by 1916 they started using it in airplane structures during the heyday of the great airships it was used in the frames of these giant vessels including the Graf Zeppelin USS Los Angeles and probably any other airship you've ever heard of from that era fast-forwarding a few years to world war ii and the u.s. started using it as armor plate now it wouldn't stop a 50 caliber or 13 millimeter bullet certainly not one fired from close range at a steep angle but it would deflect bullets coming in at a shallow angle relative to the armor 30 caliber or 8 millimeter bullets anyway in the case of the Corsair they use this thick plate on the upper Cowell deck above the fuselage tank the fuselage mounted fuel tank in the Corsair is self-sealing but there are limits to everything and some extra armor here is probably a good thing getting off topic for a moment derp all was not unique to the Corsair the Douglas a26 invader he also used it the a26 invader not to be confused with the b-26 Marauder was quite advanced the invader had heavy steel plate protecting the crew but it also made tremendous use of dural to protect the cockpit from bullets coming in as shallow angles notice the dural plate under the engine cowlings you might wonder what are they trying so hard to protect there in fact let's look at the steel plate again for a moment notice this area is fortified fore and aft with steel plate back to the other picture and you can see that it has der all below that armor is there to protect the propeller feathering pump it's not there to protect the a26 from losing an engine you couldn't possibly add enough armor to do that it's there to ensure that if an engine is lost the pilot will be able to feather the propeller to understand this let's have a quick look at this RAF mosquito that returned from a mission with an engine out note that the aircraft's left propeller blades are turned so that they show a minimal profile to the oncoming air this is what's called the feathered position and it's the position you want the propeller in if you've lost the engine a propeller that's not feathered will windmill and cause a huge amount of drag so much so that in most cases the plane will not be able to hold altitude with the power from the remaining engine thus if enemy fire knocks out an engine and the feathering pump typically the remaining engine will only serve to carry the plane to the crash site to protect against this and improve the odds of getting the plane home in this situation they protected the feathering pump with armor I know we've gotten a bit tract here but as long as I brought up the a26 invader let me mention a few more things about it I think it's a very underrated airplane it had a lot of firepower advanced gun turrets a lot of armor protection a laminar flow wing with dual slotted flaps and it's powered by twin R 2,800 engines with dual speed superchargers and water injection putting out 2,000 370 horsepower each at war emergency power carries a greater bomb load than most medium bombers and has a top speed of 355 miles per hour making it difficult to intercept in over 11,000 missions in Europe only 67 a 26 s were lost back to the Corsair one last thing about Armour it appears from diagrams that the later Corsairs had additional dural plate but I can't confirm that if anyone has source data on that other than this diagram I'd love to hear about it let's talk about that long nose originally the Corsairs cockpit was located conventionally due to a pre-production armament change to six wing mounted 50 caliber machine guns combined with the wing folding mechanism there just wasn't enough room left in the wings for large fuel tanks and the Corsairs are 2,800 engine needed a lot of fuel since both fuel and self-sealing tanks are heavy the tank needed to be located over the planes center of gravity for balance reasons the only way to do that was to put it about where the pilots at and move the whole cockpit back so that's what they did this seemed to be a decent solution but then the US Navy found that the decrease in forward and downward visibility made the plane just too difficult to land on carriers and they rejected it for carrier duty limiting it to land-based operations mostly with the US Marines this was probably a huge blow to the Corsair design team a lot of the expense and the design of this plane revolved around its wing folding mechanism which was very strong and hydraulically operated limiting it to land-based operations negated some of the big features of the Corsair design nevertheless the plane did do extremely well as a land-based plane but then on the other side of the world something happened the British figured out that the Corsair could be landed on a carrier by flying a curved approach so as to keep the deck and landing signal officer in view just forward of the inboard section of the wing this wasn't ideal but it was still difficult but it was doable and the Corsairs ruggedness and performance made it worth doing the British carriers made a significant contribution to the war effort in the Pacific during the last 15 months of the war the exploits of the British fleet in the Pacific are rarely discussed but were significant even the British themselves seem to forget about this part of the war when the sailors from the British Pacific Fleet went home they often found that their countrymen didn't even know about the war efforts of the Royal Navy in the Pacific and worse the British Pacific Fleet wasn't even represented in the London victory celebrations of 1946 the fleet was one of the largest ever and contained six fleet carriers and four light carriers and quite a few smaller carriers on board these ten main carriers the Corsair was the most common fighter by far only one carrier was equipped with Hellcats - with sea fires the rest had Corsairs I realize I'm straying off topic a bit here and into subject matter outside the usual scope of my channel so I'll just add that the british pacific fleet engaged in many important battles including attacks on mainland Japan Okinawa and in naval engagements against Japanese carriers the British carriers and their Corsairs did really well even when the kamikazes reached the carriers they did minimal damage because unlike the US Navy the Royal Navy had armoured flight decks after the war the fleet stayed in the Pacific and performed humanitarian duties that's all I have to say on this topic but I would like to see someone with a more historically oriented channel tackle this in more detail military aviation history and military history visualized both come to mind as both are good channels in a field where many are not so we've covered a few of the Corsairs oddities like aluminum armor the long nose the resulting difficulties with carrier landings but there are a lot more unusual features the Corsair has dive brakes the designers wanted it to be effective as a naval bomber and at the time dive bombing was the only form of bombing proven accurate enough to reliably hit ship's maneuvering at sea however they couldn't put in conventional wing mounted dive brakes as seen on this dauntless here because the Corsairs wing had other higher priority design requirements so the designers of the Corsair used short and very strong main landing gear to do double duty as dive breaks by using the dive break control in the cockpit only the main landing gear will extend and the tail wheel stays retracted since the tail wheel and related doors would suffer damage at higher speeds when using the dive break control the main gear could be extended at speeds up to 225 knots indicated once extended the plane could dive at steeper angles at a given speed than it could with the gear up continuing on with the gear the Corsair is one of the first planes to have its main gear fully enclosed when retracted certainly the first u.s. Navy plane even typical land-based airplanes like the p40 BF 109 and Spitfire didn't have that at the time the Corsair entered service let's talk about the tail the vertical stabilizer is located really far forward on this plane some other planes are that way the de Havilland Mosquito is one and it's common although to a lesser degree on some modern airliners I don't have a specific source for this related to the Corsair but normally tails are built this way for structural and not aerodynamic reasons pretty sure that's what's going on here the vertical stabilizer via the rudder puts a large asymmetric twisting load onto the fuselage thus the vertical stabilizer has to be very solidly attached the Corsairs fuselage tapers down a lot at the rear and there isn't as much metal to attach to farther back you go add to that the fact that the space back there is already taken up and the cow and the structures compromised to some extent by the retractable tailwheel in a restaurant I just don't think they had enough solid structure back there for the vertical stabilizer of course this isn't a problem for the horizontal stabilizer since it creates a symmetrical force on the fuselage and attaches to the structure and transfers its force very differently some modern airliners are a bit like this they don't have retractable tailwheel zora restaurants back there but they often have axillary power units in the tail and often have the vertical surfaces forward a bit the Boeing triple7 comes to mind let's go back to the fuel system for a moment most of the world war ii Corsairs have two fuel tanks one in each wing each with a 62 gallon fuel capacity in addition to the 237 gallon self-sealing tank in the fuselage the fuel tanks in the wing are not self-sealing instead they can be purged with co2 prior to entering combat this makes the atmosphere in the tank above the fuel inert the system also purges the lines to the wing tanks it does not remove the fuel in the wing tanks so although the manual doesn't say this I'm sure that once the tank is hit after some period of time if it gets hit again that's not going to be so good of course within our 2800 engine you could probably use all that wing tank fuel up before you get into combat and then purge them which is probably what happened more often than not the fuselage tank is pressurized by supercharger boost taken from the intake manifold and passed through a regulator this ensures the fuel pressure doesn't drop at altitude due to the formation of vapors in the tank however if the tank is hit hard enough so it doesn't fully self seal and starts to leak this system will force fuel out of the tank at an accelerated rate of course we don't want that so to minimize leakage in this case the pilot can shut that system off remember those co2 bottles in the cockpit let's look at them again World War two aircrafts are typically really terrible in regards to economic s-- and the Corsair is about average in this regard it's certainly not great this is a good example it's possible when heading into combat and it's time to blow the co2 into the wing tanks you could finger fumble this and blow the gear down even with the gear control in the up position once you do that you can't bring it back up and you're easy prey for enemy fighters I read one account of a pilot being killed from this exact scenario I think I read about that in the book the Jolly Rogers about VF 17 and Tom Blackburn I know I read it somewhere I'm just not 100% sure it was in that book if anyone knows of that story and the source please post that in the comments below it's time to discuss the bent wings often these are called cranked wings or inverted gull wings I consider any of these terms acceptable although some people get quite hung up on aviation terminology in nearly every single book or video on the Corsair they tell you that the bent wings are there so that the propeller will clear the ground that's not incorrect it's just that it's really far from being complete it's sort of a kindergarten level explanation and one that is obviously incomplete because there are numerous planes that use the same engine and don't have been wings for example the Hellcat and the Thunderbolt they both use the are 2800 engine with propellers nearly the same size the Hellcats propeller is 1.5 inches smaller in radius and the Thunderbolts is only one inch less in the case of the Thunderbolt used telescoping landing gear which introduced complexity that the Vaught designers didn't want in a naval fighter so we'll use the Hellcat for a comparative explanation let's start by looking at the Corsairs fuselage note that it's equally round or I should say essentially round until you reach the cockpit and its diameter is about equal to the diameter of the cowling again until you reach the cockpit this is because the Vaud engineers were really focused on performance and they wanted the Serah to be competitive with land-based fighters and a part of that goal was to have a 400 mile per hour top speed to help reach that goal they wanted to keep the fuselage frontal area to a minimum however the are 2,800 engine which they selected for this design required oil cooling and intercooling and lots of it the normal solution for a radial engine fighter was to locate at least some of those components or they're related in takes for ducting at the front of the fuselage let's take a look at the grumman f4f wildcat here its landing gear and inner coolers are located in the fuselage which contributes to its girth by the way notice the mid mounted position of the wing better yet notice that the wing is mounted to the fuselage just about in line with the propeller spinner that's going to matter later nevah didn't want to do it this way they didn't want a fat fuselage so they located the inlets for the oil coolers as seen here in the inboard section of the wings leading-edge these inlets also send air to the inner cores which are not shown in this picture now let's take a look at the Hellcat the Hellcat which is in the foreground has a has wing mounted landing gear and to help it reach the ground look how far down the wing is mounted relative to what we saw on the Wildcat it's about in line with the bottom of the engine the fuselage area below that line is for ducting and coolers add in the fact that the Hellcats gear is much longer than the Corsairs and the prop has a 1.5 inch smaller radius and we can see why it doesn't need bent wings note the Bearcat in the background has telescoping year like the p-47 I suspect the shorter gear in the Corsair was a lot stronger than the Hellcats it's extension speed is certainly much higher 200 knots for the Corsair and 225 in dive break mode versus only 135 knots for the Hellcat those limits are usually controlled by the extension system and not always the gear itself but still it's a huge difference and the Hellcats gear not do double duty as a dive break I watched quite a few carrier crash landing videos and I didn't find a single one where a Corsairs landing gear broke off of course the Hellcat served on carriers earlier so it could just be that there are more videos of the Hellcat but still I found quite a few videos where the Hellcats gear broke and often where the fuselage broke somewhere after the cockpit in similar crash landings with the Corsair I never once saw a broken gear and the plane seems to hold together really well the Corsairs fuselage doesn't have enough girth to mount the wing low enough for the gear to reach the ground and neat at least not if it's going to be short enough to retract into the existing wing and double as a dive break however there is another issue and it's related to speed there are different types of drag that affect airplanes and one is called interference drag and it's a big factor I've referenced the pilots handbook of aeronautical knowledge here it's extra drag caused by the joining together of two surfaces like everywhere the fuselage connects to something else wing or tail component NACA did many studies on this and found that the area where the fuselage joins the wing route is a significant source of interference drag they tested various points of attachment and found that a wing that joins the fuselage at about a ninety degree angle is about ideal if the Corsair had a straight wing that joined the fuselage at that angle it would be mounted about in line with the propeller spinner much like what we saw on the Wildcat imagine how long the gear would have to be then so by using the bent wing design they could not only have the propeller clearance they could do it without the telescoping gear they could do it and still keep the fuselage frontal area to a minimum and reduce interference drag so it's not entirely correct to dumb this whole thing down and say that the bent wings were just so the propeller would clear they could have solved that with telescoping gear but that would have added complexity and sacrificed strength and the dive break capability of the gear they could also have solved it with a fatter fuselage combined with longer gear but that would have sacrificed the gear strength and slow the airplane down the bent wing created enough propeller clearance without sacrificing gear strength or speed and that's the point of the design of course the extra complexity of the wing design offsets the gains a bit but overall it results in a net gain which is why they did it all of this enabled the Corsair to exceed its design goals and have a top speed in excess of 400 miles per hour and below 20,000 feet it was competitive with land-based fighters throughout the entire war once the US Navy started putting Corsairs on carriers they became the dominant fighter in the US Navy the plane stayed in production until 1953 making it the last of the world war two naval fighters to be produced even outlasting the Bearcat I have one last thing to mention the Corsair went on to have a long military career and ultimately scored the last air-to-air kills by a piston engine fighter this happened in 1961 when a disagreement over a soccer game I'll back up for a moment soccer is a British word for association football I'm not quite sure how you get the word soccer out of Association I think it might have something to do with warm beer and Lucas electronics but in any case in some parts of the world they call this sport soccer football but it's not what we in the u.s. call football so it gets a bit confusing regardless apparently some people in Central America are really into this sport and a disagreement over one of the games set off a short war in which both sides were flying u.s. World War two airplanes the Corsair came out on top with one scoring three air-to-air kills at least one of which was against a p-51 the corsair pilot reported that he was able to easily out turn the p-51 and get the shot so I hope you enjoyed this video I know I got off topic a few times I sort of avoided engine stuff and a lot of the Mack and details just for a change of pace the Corsair is our 2800 engine could easily be a video all its own so I largely ignored it in this one my next airplane video will be very heavily biased towards engine technology in World War two hopefully some of the information in this video is new to you let me know what you think in the comments section please like and subscribe for more and thanks for watching and have a great day you [Applause]

Channel: Greg's Airplanes and Automobiles

Views: 216,102

Rating: 4.9261646 out of 5

Keywords: F4U, Corsair, F4U Corsair, Duralumin, Dural, Aluminum armor, Inverted gull wings, cranked wings, bent wings, carrier landings, British Pacific Fleet, CO2 purge, Corsair tail

Id: rNcV13uayxw

Length: 23min 58sec (1438 seconds)

Published: Sun Sep 09 2018

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[u/when_adam_delved]

"The F4U Corsair is probably the most easily recognizable plane of World War II" as a P-38 strolls into view.