P-51D Superiority

[Romantic Technofreak]

First let me introduce myself as a new member. I live in Germany and since many years I am interested in air-WWII history. I won´t like to share the "best fighter" discussion because for me the case is clear: the P-51D "Mustang" is it. The reason ist that it fought the victory over Germany at the crucial point of time (early 1944). But I still have some questions about it, as I did not study aerodynamics or motor engineering, and the Mustang´s success surely bases there. So how can you fix the superiority of the Mustang? From my books I know the following:

1) Laminar wing profile (unknown in Germany before evaluating emergency-landed Mustangs?)

2) A special radiator construction, providing additional thrust (how can you imagine this?)

3) Use of high-temperature-resistant material for the motor, unavailable in Germany at that time (or disappeared in the tank production?) and giving the Mustang a top height of 2.000m over its German opponents (except some late versions of the Me 109)

4) Ability to outturn the Me 262.

Please give your comments and additions!

[simon]

In all honesty the ceiling is pretty much irrelevant.

Why? Well the Mustangs were basically tied to the bombers. OK the fighters were allowed a degree of tactical flexibility when it came to their deployment, but at the furthest they'd be 10,000ft higher, so if your main bomber force is operating at say 25,000ft with bombs, the Mustang escorts will be at most at 35,000ft, so a Bf109G could still be 2,000ft higher than the escorting fighters.

Ability to outturn the Me262? Again irrelevant, only 300 Me262s reached combat units and all during or after summer 1944, so this really was not important.

I'm not aware that the Mustang's unusual radiator arrangement did anything other than stop the engine overheating!

You've missed one vitally important factor in the success of the Mustang. The incredible range. That centre line tank allowed the Mustang to escort B-17s and B-24s all the way to their targets within Germany, Berlin if necessary and all the way back. That's why the Mustang was so important, without it the daylight strategic bombing offensive would either have not happened, or been even more costly.

I don't think the Laminar flow wing was unknown in Germany, or unique to the Mustand, I'm pretty sure the Spitfires had laminar flow wings, and they had a good 6 year headstart on the Mustang. My understanding is that the real benefit of the Laminar flow wing is that it allows the aircraft to travel at a much higher top-speed before the ailerons become unresponsive.

My own feelings on the Mustang are well documented so I wont repeat them save to say I don't think the Mustang was necessarily the best fighter but it almost certainly was the most important as far as the conduct of the airwar in the west was concerned.

Finally, the really importand battles as far as leading to the ultimate defeat of the Luftwaffe is concerned were actually fought before the arrival of the Mustang, and were fought with Thunderbolts, Lightnings, Spitfires and Typhoons in Autumn and Winter 1943, this was when the Junior leaders that should have become the next batch of instructors were killed or incapacitated.

Oh yeah, welcome onboard, good to have another new poster!

[Romantic Technofreak]

Hello Major Simon, thank you for answering. About the question which battle was the crucial one we are dissenting. My sources say that the struggle against the American day-bombers, protected by Mustangs, was it, although the Luftwaffe went already weakended into this fight. But let us discuss that another time, I would need a really good database for a qualified opinion on this.
The range argument for the Mustang is only valid against its allied competitors. In fighting you need speed, maneuverability and ceiling. Even if the Luftwaffe had had enough airplanes and pilots in early 1944, they would have been outclassed by the Mustangs.
Why that? There are some facts that should not be dissented in the traits the German fighters of that time had.
The ceiling of the FW 190 A-series was insufficient, compared to the Mustang. Sometimes it was even not easy for the FW 190 to reach the operating bombers, let alone perform a dogfight against Mustangs.
The speed of the Me 109 G-series was insufficient, compared to the Mustang. Other German fighters were not available at that time. And anyhow, the Mustangs flew high enough to dive down at their opponents because they were ordered to attack the bombers, so the Mustangs had a considerable and crucial speed surplus.
So, what is the mystery behind the performance of the P-51D? It is not the engine, although the Mustang´s Merlin was a bit stronger than the Me 109 G´s DB 605 A. The Me 109 K´s DB 605 D needed 300 hp more than the Merlin to match the speed of the P-51D. And this, although the Me 109 is smaller and sleaker than the Mustang, this way it should be better in terms of front and inducted drag.
So let me repeat the two things I was told. First, the laminar wing profile. The evaluation of the Mustang directed Kurt Tank to develop the Ta 152 from the FW 190D, thus receiving a speed surplus of 65 km/h!
And second, the way to make the radiator air leave the airplane body may really be important. My understanding for physics says that a heated gas has to expand and can be used for to provide thrust. Can you imagine the Mustang´s radiator to work a little bit like a ramjet?
And what I would really like to know: Is these to things all, or does the Mustang have still more hidden qualities?
Thank you for your attentiveness. Let more arguments follow!

[Corsarius]

Welcome to the boards!

So it seems we have a bit of a monomaniac here.

Perhaps the mustang could out-turn the 262.. so what? The 262's primary mission and armament was aimed at fighting bombers, not fighters. Besides, it's high speed allowed it to dictate the terms of combat. Should they be unfavourable, then the schwalbe could simply go away, unhampered by a lamilar-flow wing aircraft that was simply insufficient to play catch-up. Besides, the schwalbe's swept-wing profile and leading edge slats were arguably more advanced than the lamilar flow-wing of the mustang, as they were incorporated into the later F-86 sabre, which succeeded the mustang.

As for additional thrust generated by the radiator? Sure, I'll go with that. I've heard it elsewhere and believe it to be true. In a similar fashion the Japanese added speed to their fighters by using stubs that concentrated the exhaust of the radial, providing a few more kph in speed.

Basically, a lamilar-flow wing WAS more efficient than a traditional wing structure, such as that of a hurricane, but not as advanced as a swept wing (Me-262), a tailless swept wing (Me-163/263), an all-wing design (Go-229 and various Northrop aircraft), or a delta-type design (Do-223).

The Mustang's chief attribute was RANGE, not that it wasn't a great fighter, but I'd put a 'Jug' against it any old time. For speed, should that be the only case, then the Lightning was a superior beast, and the schwalbe and 109K-14 easily outstripped it (in climb as well as dive and straight. Remember that the Schwalbe's critical mach no was .95, and the 163 was .98 in a dive!)

As it has been said in other arguments, it was mass-production of aircraft at unreachable locations that won the war, not any single aircraft. The US could have just as well churned out zillions of P-26 fighters and B-9 bombers and achieved similar results, albeit at considerably higher cost (much, much, more considerably!). The US was in an unassailable geographic and industrial position. Even today it would be very difficult to stage an invasion of the US, whereas Europe has many points where it could be attacked from (Africa and the former SSSR spring to mind at one point in aviation history or another). Surrounded by allies and oceans with a powerhouse industrial centre (although not necessarily so technologically at the time, as they didn't need to be) the US could afford to build aircraft and other material for itself and for it's allies with relative impunity.

I mean, who got to attack the US during the war? The single German sortie didn't carry bombs (contrary to rumours that I have to keep squashing of German aircraft circling the statue of liberty), and the Japanese Fu-Go bombing programme wasn't exactly 'precision' if you get my meaning....

So to the meat of the argument, the P-51D was a great plane at the right time, but by no means was it the 'best'. Go have fun reading the 'best fighter' thread to see what was hammered out as a (tentative) best fighter.... you may be surprised and/or disappointed that at last count (I think!) it was the FW190D.

[Romantic Technofreak]

Thank you for answering me, Captain Corsarius. No, no I am not a monomaniac, but for proving that I need more time. Generally, if you chose a "best" plane of an entire war it is somehow arbitrary if you choose one not from the very end of it, because you miss the technological development ocurring during the remaining time. Why I made my choose I told already. Especially the advanced German developments (Me 262, Go 229, FW 190D, Me 109K, Ta 152, Do 335 (I am sure you meant this, because RLM No. 8-223 was the Focke-Achgelis helicopter) were not available in early 1944, and I cannot consider the Me 163 as a fighter at all (sorry if I hurt you, because you love it, but the Komet was not able to press home on its own drive), to underline that it suffered more losses than achieved kills during its short combat career.
So, if the top speed is the crucial thing, as you mention, my sources say the following:

Mustang 703 km/h
Thunderbolt 689 km/h
Tempest MkV 685 km/h
Re. 2005 678 km/h (if there is still one alive)
FW 190A 670 km/h
Lightning 666 km/h
Me 109 G-10 661 km/h (estimated, using water injection for 1.800 hp)
Spitfire Mk IX 652 km/h
Typhoon MkIB 652 km/h

although I have to admit that top speeds often are a "depends on whom you ask" problem. What a P-51D aviator thinks about the Me 262, let us ask Major "Bud" Anderson:
www.cebudanderson.com/faq.htm

My focus was on a special battle. To win the entire war for the axis is a very different problem. Of course, because I am German, the thought of how we and our allies could have won WWII is an interesting question. Please don´t misunderstand me, I am not a Nazi and I am glad that we did not win in reality because Hitler would have made an end to the kind of world we all love. But thoughts are free!
Especially if you say the U.S. could have won even producing outclassed airplanes I have to contradict you intensely. Maybe the U.S. industry could have replaced the planes if they were shot down in bunches, but what about replacing the crews? In late 1943 the FW 190s would have strangled the American bomber offensive if the Mustang had not appeared on the theater. And what if the Mustang would have been defeated? What if the air over the beaches of Normandy was filled with German airplanes instead of allied ones?
What if the U.S., producing armament undisturbedly, had to suffer one, two, three or more big defeats overseas? In fact they had to suffer none. And what if they were not able to keep the seas open and the axis fleets creeping nearer and nearer to their coasts?

O.K., it is a nice surprise that you chose the FW 190D as best fighter. But to return to my opening theme, what about the Ta 152, what mainly was a FW 190D with laminar-flow wing profile?

[Corsarius]

Oookay. Now It's my turn to look silly. I mean the Do335 Pfeil, arguably the most advanced piston-engined aircraft to see squadron service and (very) limited combat.

[GregP]

Hi,

I have to chime in here. Hi Technofreak and welcome.

The Liminar flow wing has several advantages over a conventional wing. The most notable advantage is a higher critical mach number and less drag ... assuming laminar flow. Most laminar flow wings only achieve partial laiminar flow, and the Mustang is surely in this category given that it was parked outside, was not waxed regularly, and it did not have a boundary layer vacuum system. So, I conclude partial laminar flow.

The P-51 radiator was amazing. Most aircraft suffer a drag penaly with a liquid cooled engine due to radiator drag. The P-51 had an ingenious adjustable outlet for the radiator exit taht allowed the system to narrow down the intake until optimum cooling was achieved. I am quoting this from memory, but I recall reading that the P-51D achieved a 150-pound thrust (330 kg or so) from the radiator while most other liquid-cooled aircraft at the time incurred a drag penalty for having a radiator.

So, the Bf 109 had radiator drag while the P-51 had radiator thrust.

Also, the canopy of the P-51 produced much less drag than the squared-off canopy of the Bf 109.

The frontal areas of the Bf 109 and P-51 were not much different from one another, so form drag is about a wash.

However, wing placement plays a very important position in drag calculation. The wings of the Bf 109 were placed forward enough to cause more drag than the wings of the P-51, which were placed more to the center of the aircraft.

The riviting on the P51 was pretty flush, making for a smooth skin. I have seem Bf 109's and they are not particularly smooth.

Last, but not least, we come to an important difference ... the propeller. The propeller of the Bf 109 was never very optimzed and it was made of wood. While wood propellers are best for aerobatics, metal, when correctly formed, has a much smoother finish. The Aeroproducts props on the P-51 were MUCH better airfoil-wise and finish-wise than the Bf 109 or, in reality, most german WWI propellers. One notable excpetion are the paddle-bladed propellers on the high-altitude versions of the Fw 190. They were also of wood, but were well finished and worked very well at high altitudes.

Some later models of the P-51 were almost identical to the P-51D, but had a prop with a normal airfoil instead of the stepped Aeroproducts airfoil. They were NOT as fast and did not climb as well as the Aeroproducts unit.

The P-51D had its faults. It was a nadfull when the fuselage tank was full (very aft CG location) and could not really dogfight in this condition. Fortunately, the fuel burned off on the way to Germany so, by the time they GOT there, the P-51's were NOT in an aft CG condition. The P-51 rolled better than the Bf 109 and, indeed, better than most other WWII fighters. The Fw 190 was probably the rolling champ, but it could did not have a sustained turn rate to go with the exceptional rolling performance.

I believe the Fw 190's transient turn rate was good but, when the fight got past 20° or 30° of turn, the P-51D was a MUCH better turning machine.

Stilll, the primary reason the P-51D was such a winner is, to me at least, very clear.

The U.S.A. had more P-51's in good condition than Germany had opposing fighters. We also had a large supply of well-trained pilots. By the time the P-51D GOT to the fight, Germany had lost a lot of great pilots to combat and they were still flying the Bf 109 as a main fighter.

I'm not sure if you know it, but there were about 33,000 Bf 109's built. More than 10,000 were lost in takeoff and landing accidents. So, Germany lost 1/3 of the Bf 109s to bad landing gear placement!

Another point, the ailerons of the Bf 109, while wondrous at 250 mph, were almost imovable at 400 mph. The 109 also lacdked rudder trim! So it was VERY tiring for the pilots to fight vertically, despite the 109's good climb rate.

I'd say the Bf 109 was a superior fighter at meduiom speeds (for which it was designed). Once the fight got to 350 mph and beyond, the P-51 was in its element.

Last, the Bf 109 had MANY different armaments during its heyday, but a large number of them had one cannon firing through the propeller hub and two rifle-caliber machine guns. The Bf 109F, for instance, had two 7.92 mm MG + 1 20 mm Cannon (MG151). The cannon had a slow fire rate, so the Bf 109 was mostly spitting bullets from two machine guns.

The P-51D has six 12.7 mm MG and the rate of fire was high when compared with the two MG on the 1209 plus the occasional cannon slug. Since hittign a fighter happens only in small amount of time, the two MG were more important when rate of fire is the criteria. Sure the cannon slug will do a lot of damage, but if you only have the P-51 in your site for 4/10 second, how many cannon slugs can you put into it.

The Bf 109F could put out 1.04 kg per second of fire while the P-51 , with the six MG, put out 3.64 kg per second of fire.

Therefore, I contend that the Bf 109, while a good low and medium speed aircraft for the intended function, was underarmed and was a lareg handicap at high speeds. Ergo, the P-51, which had the range to get there, was the winner for a large number of reasons, only one being the choice of a liminar airfoil.

For you reference, the late model Spitfires has a higher critical Mach number than the P-51's did, and it was one of the fastest of all propeller-driven planes in a dive. But, there were not anmywhere NEAR as many late model Spitfires around as there were Mustangs. Also, the really late models added a fuselage gas tinak that addressed the short range and, had they been made in numbers, or had the war continued, the Spitfires would have also escorted the bombers to Germany and back.

I contend that had Germany developed a better fighter sooner with suitable armament, or had they addressed the bad landing gear geometry, the abismal canopy, the position of the wing and the armament, the Bf 109 or the "new" fighter could have made a real difference. I suppose we'll never know since this never happened.

Comments Corsarius or Simon?

[GregP]

Hi again, in my above reply, I said the P-51 had a radiator that could narrow down the intake.

That is obviously wrong. I meant narrow down the radiator air outlet or exit.

Wish I could TYPE!

[tenmmike]

Romantic Technofreak im not a big p-51 guy but here is a display of radiator for you http://www.icon.co.za/~pauljnr/radsta.jpg

[GregP]

Nice post. I have read that there was actually thrust produced, but a 90% reduction in radiator drag is akin to a 90%thrust using the dame radiator, so maybe it's so.

In any case, the radiator in the P-51 was WAY better than any other radiator installation in any other mass-produced fighter in WWII. You MIGHT find a one-off with a better setup, but the major fighter aircraft did not include anything with a better liquid-cooled setup than the Mustang as far as I know.

For the best propeller, I'd choose Aeroproducts, hands down, though Dowty-Rotol also did a good job, as did the Focke-Wulf with the Fw-190D, the Ta -series, and any other high-altitude variants of the Fw 190.

Not really sure about Italian proprs, but they DID produce some very good-performing fighters near the end of the war, so maybe they were right in there. Ditto the USSR, though we really don;t know about high-altitude performance since their main fighters didn't HAVE any altitude performance to speak of, with the exception of prototypes.

Some of THEM had pretty decent performance, too.

I still pick Aeroproducts as WWII's "best prop."

[Corsarius]

Re your challenge GregP.

Yes, I'd agree most strongly that the US had superior manufacturing and economy to push out more aircraft, thus the technology edge the Germans enjoyed became more negligable. The Germans DID address the 109's problems by creating a long-awaited replacement (that never saw service) called the Me-309.

I found a pic here
http://www.warbirdsresourcegroup.org/LRG/me309.html

About the only one I could find. As you can see, speed, armament, and from viewing the picture, wing placement etc issues had all been addressed, but with conflicting orders from high command, and a dodgy manufacturing base that could hardly afford too many experimental craft, it didn't really see much of the light of day. Instead, the Me-109 just got dragged back in for yet another remake.

In my opinion, the -109 should have terminated in the "F" model, which is my favourite, and then the 190 or perhaps the 309 could have taken over should they have been available. That they weren't meant that the "G" and then the "K" models were turned out. The designers knew that they were trying to rebuild what was essentially a pre-war aircraft to a current standard. Imagine a modern anologue.. oh yes, we have one, the noble Canberra bomber. Well past it's prime and should have been put to pasture years ago, and yet it still soldiers on in RAF service (in limited numbers).

[simon]

Just got to stick my oar in again, multiple answer to everyone I'm afraid.

The Bf109's (Bf for Bayerisch Flugzeugwerk, rather than Me for Messerschmitt!) problems had largely been corrected by the Me309, which featured such advances as cockpit pressurisation and a retractable radiator, however the 309 was an unsatisfactory machine. According to the sources I have it could be out-turned by the Bf109G and was judged inferior to the Fw190D-9 already inservice so would have been unlikely to solicit any orders in any case.

OK, although slightly sceptical I'll go along with the idea that the Mustang's radiator generated a slight thrust, however was this what made it so successful, seriously, I doubt it.

The Range argument is far from irrelevant when considering the Mustang's success over the Luftwaffe, it is key to it. Speed, armament and manouevrability are all completely irrelevant if you cannot take the fight to the enemy, if the Mustang had not the range it did the Luftwaffe could have chosen to simply ignore it as they did in the early stages of the US bomber offensive when facing Spitfire MkVs and Thunderbolts without drop tanks. The Luftwaffe knew the Allied fighters would not have the range to take the bombers all the way to the target and back so they simply waited until they had to turn back, then attacked the unescorted bombers.

When the Mustang appeared this was no longer an option, they had to attack the bombers with their escorts, the only alternative was to allow the USAAF to bomb Germany unhindered and that was obviously not acceptable.

Secondly the range of the Mustang also allowed the USAAF's free ranging fighter sweeps to engage the Luftwaffe at any point, whether it be in the air, or when they were more vulnerable such as when taking off, landing or parked on the ground.

My understanding is that the US did actually credit ground kills towards the end, as this encouraged pilots to engage in Ground Strafing of airfields. One or two passes and you could be an ace.

The comment has been made that the Fw190 struggled to reach the bombers, my understanding is not that this is because it had insufficient ceiling, although certainly the Fw190A series was a better performer at lower altitudes, but because it was acting in the role of an interceptor, meaning that whereas the US bomber and fighter formations could form up over England, climb to say 20 or 25,000ft then set off for Germany, the Fw190s were being scrambled from the ground, by the time they reached the height of the bombers they would have been climb all the time and reacting to radar vectors. The high escort of P-51s could then dive, adding diving to their already existing speed advantage and hit the Fw190s before they even reached the bombers.

As for the cannon on the Bf109, well I don't think you can discount, certainly not early on in the G series where it mounted an Mg151/20, perhaps later when the much slower firing 30mm Mk108s were introduced. Seriously though, if cannon were so ineffective, the RAF would have never altered the original 8 gun layout of the Spitfire MkI.

If you want Romantic Technofreak, you can discount the issue of range, but to me as I've said above it was key to the Mustang's success. Yes by the time the Mustang arrived the Luftwaffe had become largely a second rate airforce flying old designs, but even a second rate airforce can shoot down unescorted bombers.

There's a great phrase which soemone, I think it may have been Ricky, used in the Fighter's thread. The Mustang can't do what the Spitfire can, but it can do it over Berlin. That's why the Mustang was successful, not a marginal thrust generated by its radiator, not a laminar flow wing which in any case had been in use since 1936. Not a high resistant material, which in any case would only lessen maintenance. Not Ceiling. Not the ability to out-turn the Me262.

Range.

[Romantic Technofreak]

Hello everybody, thank you very much for your replies!

Captain GregP, that was what I needed! I am going to store your text for my files. Only problem was that I still could not imagine how that crazy radiator works. Tenmmike, you got me out of that hole. I shall study that draft, hopefully I get enlightened.

Simon, I think there is a misunderstanding between us. I do not discount the Mustang´s range, for me it is the prerequisite for choosing it as a "best fighter". But it was not worth a discussion for me, because the functions of the fuselage tank and the reliable and economical Merlin motor are easily to understand for me, while the other qualities really made me wonder. As GregP pointed out, there would be a German fighter with special traits required to beat the Mustang, but range is, I think, not necessarily among those traits.

When I looked at my speed list once again, I realized that the Re. 2005 made it´s very good performance by using a copy of the German DB 605 with only 1.475 hp! Estimations by using the water/methanol injection booster with the same engine lead to a result of 724 km/h, using the same equipment together with the Jumo 213 delivers 2.250 hp and an estimated top speed of 780 km/h! Having only the Mustang´s 1.700 hp available, it still runs 711 km/h.
If you ask me personally, the results for the Re. 2005 are very doubtful. It beats its comrades of the Italian "Digit 5" series by 35-50 km/h, and how should this be possible? On the other hand, when I look at the silhouette of the Re. 2005, it might be even made faster by prolongating the rear fuselage, as we in Germany say "Länge läuft" = "length runs"!

[simon]

I will agree with you and disagree at the same time.

The Luftwaffe would have needed greatly superior aircraft or greatly superior numbers to defeat the US in the air, but they had neither. The Luftwaffe had superior aircraft (The Me262), but not aircraft that were good enough, or in enough numbers to tip the balance, and as commented on the other threads, not enough servicable or reliable aircraft and no way of effectively countering the Allied strategic bombing offensive.

Sometimes though to see the real reason for a war or battle turning one way or the other you need to look beyond the technology employed and see that the strategy or tactics used to employ it are just as important if not more so than technological advantage. This was the edge for the US, they had a far better understanding of Aerial warfare, and all the while the Luftwaffe had Goering and ultimately Hitler at the top they could produce as many planes of whatever capability as they wanted, it wouldn't make any difference because the correct thinking just wasn't in place to use them in the right way.

Apologees for the misunderstanding.

What part of Germany do you come from BTW, I lived at varying locations along side the British Army between 1980 and 1996?

[GregP]

Nice post Simon.

I am good at miscommunicating! There is no doubt that the Musrang's range was a big advantage and a major reason for its success. However, I was attempting to address Techno's question on why the P-51 was a clear winner over the Bf 109 with an engine of almost rqual horespower.

It was faster, rolled better, had a better sustained turn rate, delivered more weight of fire per second, had better visibility, and a better propeller.

Obviously, if it never GOT there, the difference would be unimportant. Range DID play a key role.

However, I'd say that if the U.S.A. had produced the Brewster Buffalo with sufficient range to reach Berlin instead of the P-51 Mustang, then the airwar might nave had a very different outcome.

My only point there is that whatever fighter was given the range to be an escort to Berlin, it needed to be able to contest the Bf 109 and Fw 190 on equal or better terms if it were to be successful against them.

Nice quote about the Mustang not being able to do what a Spitfire could, but it could do it over Berlin. I like that.

From a purely academic standpoint, I'm not sure I agree with the statement. I will allow the Spirfire was generally a better turning aircraft, but I do not know about the roll performance. The ailerons in the Spitfire were not as large as the aileron on the Mustang when you llok at it from the perspective of are of the ailerons as a % of wing area, so I couldn't say.

It would be a very interesting thing to compare, and I'll look into it. What model of Spitfire would you say should be the basis for comparison? The P-51D got to the fray in 1943, so I'd say it should be a Spitfire that was availanle in combat in 1943.

Then we could compare weight of fire per second, rate of climb, max level speed, max dive speed, roll rate, and turn rate.

I'd say the Spits were very excellent, as were the Mustangs. As to which was the better fighter, I'll say that pilot skill would probably determine it. If the pilots were equal, I'd give a slight nod to the Spitfire, but not enough to really matter in the end. They were both great fighters.

Of course, the Mustang didn't rreally get to BE great until we installed the Merlin engine so, to a large extent, the Mustang owes it's greatness to the British in any case.

It would be interesting to compare the mid-1945 Mustang vs. the mid-1945 Spitfire vs. the late model Reggiane Re 2005 vs. the Fw 109D or Ta-152 vs. the MiG-3/9 vs. the F4U-4 vs. the Ki-84 vs. the Ki-100, eh?

Wish we could get an example od each one and do an evaluation of it with today's ability to collect accurate data.

[simon]

The P-51D didn't get into combat anywhere till Mid 1944, so I'd say for a fair comparison the Spitfire MkXIV.

[GregP]

OK, I looked up some gun numbers. I pasted in some figures from Excel, but they didn't format very well.



Plane Date Guns Weight of Fire (kg/sec) Muzzle Power (kW)
Supermarine Spitfire Mk I Jul-36 8 * 7.7 mm MG 1.72 480
Messerschmitt Bf109C-1 Feb-38 4 * 7.92 mm MG 0.73 110
Messerschmitt Bf109E-3 Late 38 2 * 7.92 mm MG + 2 * 20 mm Cannon 2.37 530
Messerschmitt Bf109F-1 Nov-40 2 * 7.92 mm MG + 1 x 15 mm Cannon 1.04 420
Mikoyan-Gurevich MiG-3 Dec-40 2 * 7.62 mm MG + 1 * 12.7 mm MG
Supermarine Spitfire Mk VB Mar-41 4 * 7.7 mm MG + 2 * 20 mm Cannon 2.24 1,250
Hawker Typhoon Mk IB May-41 4 * 20 mm Cannon 5.20 2,010
Macchi C.202 Folgore Jul-41 2 * 12.7 mm MG 1.13 320
Yakovlev Yak-7 Late 41 2 * 12.7 mm MG + 1 * 20 mm Cannon 2.64 1,080
North American Mustang I Feb-42 4 * 7.62 mm MG + 2 * 12.7 mm MG 1.99 730
Republic P-47B Thunderbolt Mar-42 8 * 12.7 mm MG 4.85 1,830
Vought F4U-1 Corsair Jun-42 6 * 12.7 mm MG 3.64 1,370
Messerschmitt Bf109G-5 Mid 42 2 * 13 mm MG + 1 * 20 mm Cannon 2.32 640
Macchi C.205 Veltro Sep-42 2 * 12.7 mm MG + 2 * 20 mm Cannon 3.69 970
Lockheed P-38F Sep-42 4 * 1.7 mm MG + 1 * 20 mm Cannon 3.73 1,420
Fiat G.55 Centauro Feb-43 2 * 12.7 mm MG + 3 * 20 mm MG 5.12 1,330
Kawasaki Ki-61 Sep-43 2 * 12.7 mm MG + 2 * 20 mm Cannon 3.69 1,080
Yakovlev Yak-3 Oct-43 2 * 12.7 mm MG + 1 * 20 mm Cannon 2.64 1,080
Supermarine Spitfire Mk XIV Jan-44 4 * 7.7 mm MG + 2 * 20 mm Cannon 2.24 1,250
Nakajima Ki-84 I Hayate Apr-44 2 * 12.7 mm MG + 2 * 20 mm Cannon 3.95 1,310
Hawker Tempest Mk V Apr-44 4 * 20 mm Cannon 6.50 2,300
Focke-Wulf Fw190D-9 Aug-44 2 * 13 mm MG + 2 * 20 mm Cannon 3.87 1,000
Republic P-47M Thunderbolt Dec-44 8 * 12.7 mm MG 4.85 1,830
Messerschmitt Bf109K-6 Oct-44 2 * 13 mm MG + 3 * 30 mm Cannon 10.40 1,470
Supermarine Spitfire Mk 21 Apr-45 4 * 20 mm Cannon 5.20 2,010
Kawasaki Ki-100 Jun-45 2 * 12.7 mm MG + 2 * 20 mm Cannon 3.95 1,310


From the above list, we can see that the Bf109 was woefully underarmed until the Bf109K-6, which had the highest weight of fire of any WWI fighter I can find. How many were fielded? I can't say.

The Hawker Tempest Mk V had the highest muzzle energy at 2300 kW, but it wasn't a major factor in fighter vs. fighter combat.

So, if we ignore these two models, between mid-1942 and late 1944, teh Spitfire Mk 21 has the best weight of fire at 5.20 kg/sec. A close second was the Fiat G.55 at 5.12 kg/sec. The P-47 was thrid at 4.85 kg/sec. The Bf109's were in the 1 to 2.3 kg/sec range except for the K-6. The P-51 could put out 3.64 kg/sec. The Fw 190 D-9 was 3.87 kg/sec.

Looking at the table, it seems the best armament for weight of fire per second and muzzle energy was 4 * 20 mm Cannon, but few planes HAD that armament.

From 1936 to 1945 we see weight of fire going from0.73 kg/sec for the Bf 109C-1 up to 5.2 kg/sec for the Spitfire Mk 21. Only the Bf 109 K-6 had the large 10+ kg/sec armament, aand it was not a major factor numerically. The great aces usualyl mostly flew the Bf 109 F and G models for the bulk of their kills, and these had a a low weight of fire ... which says something for their gunnery skills.

Most American fighters had 6 * 12.7 (50-cal) mm MG that gave a respectable 3.64 kg/sec.

Italian planes, while mostly lioghtly armed, were right in there by 1943 at about the same as a Mustang. The Spitfire, Mk V up through the MK XIV, had a weight of fire of 2.24 kg/sec and didn't get with the program until the Mk 21. But the British also fielded the planes with the highest firepower in terms of muzzle energy ... the Typhoon / Tempest series. The Japanese, by the time the Ki-84 got there in Apr 44, had closed the gap and even upped the ante a bit. The Ki-84 had a slight edge on the F6G and F4U in weight of fire, but not enough to call it a real advantage. They were about even, gun-wise anyway.

So, this doesn't really solve anything except to point out that MOST Bf109 variants were, in fact, underarmend ... which we all knew anyway.

Another useless bunch of facts, huh? Time for a beer.

[Corsarius]

When I first got interested in aviation history I remember being quite stunned at the weight of firepower fielded by the Zero-sen as opposed to just about anything else in the era. Same story for the FW190, certainly it made a powerful mix of ballistics.

And GregP, you have WAY too much time on your hands! :P

[simon]

You're just jealous!

Anyway I'm personally slightly sceptical of using weight of fire and muzzle power as a method of calculating effective fire from an aircraft. There's too much else that can effect things, not least of which is ammunition capacity.

For a good example of the latter consider the Bf109E-4, it carried only enough ammunition for 6 seconds of fire from its 2 Mg-FF cannon, after that it was down to a paltry 2 machine guns, so if you consider early 109s after only a short while into a combat they seem even worse!

Another problem is that muzzle energy becomes increasingly irrelevant as you start to consider especially the large cannon.

Finally an aircraft's capabilities as a gun platform greatly effect the usefulness of it's armament. The Hurricane MkI which you haven't got there but which would be identical to the Spitfire MkI was a far better gun platform, altogether more stable, and the fact that the guns were grouped closely together in the wing meant the weapons were far more likely to be firing at the point of aim. The Spitfire however was less stable and had it's guns scattered throughout the wing, the result would be that fewer rounds would in practice actually hit the target. So here in terms of the actual amount of fire that is going to the point of aim the Spitfires 8 guns were considerably less use than a Hurricanes! This kind of thing can be quite succinctly summed up by Adolf Galland's comment that a gun in the nose is worth two in the wings.

(As an aside I heard a radio interview with a Battle of Britain veteran who commented that the Spitfire MkI's outer two machine guns deflected so wildly due to the thinness of the wing as to be virtually useless as weapons!)

As with so much there are just too many variables to take into account to be able to use statistics that easily, muzzle velocity, reliability, ammunition storage and cyclic rate all play a part in determining the usefulness or otherwise of an automatic weapon in air to air combat.

BUT, it did make interesting reading... ;)

[GregP]

Hey Corsairius,

Too much time on my hands? Yep. I'm an unempolyed engineer looki8ng for work.

However, the data I quoted come from my database, which I posted about in the forum. So, the reference is right in front of me on the screen.

No big deal to look it up.

By the way, there is an issure of Flight Journal out now that is dedicated to the Corsair. Get a copy. It has some good stories and some good information about the Corsair, including early F4U-1's, the F4U-4's, and the models powered by the P&W R-4360 corncob radial of 2800 to 3000 hp or more.

With your log-in name, it would be a nice addition to your library ...

[Corsarius]

Flight Journal.. Okey-dokey. I'll check if the local newsagent stocks it (they're pretty good on British and american publications).

In any event, My name has nothing to do with that sterling fighter, but is an anachronism all to itself. Still, I always liked the idea of a fighter plane built by Goodyear. When I was a kid I thought they were made of rubber and the bullets would just bounce off!

[GregP]

Corsarius, if you can't find the Flight Journal Corsair issue, let me know. I can get an issue and mail it to you. However, don;lt wait too long or they'll be off the shelf!

I assumed you must be a fan of the Chance-Vought Corsair ... simply fromyour log-in name. If that is not so, I'll cease advising you of things I find about the plane if you prefer it.

I think it was a good looking plane marred by an ugly vertical tail. Also, I cannot imagine a plane with poorer forward visibility in the landing pattern or on the ground, but in the air at patrol speeds or above, it was wondrous.

[Grendel]

> 1) Laminar wing profile (unknown in Germany before evaluating emergency-landed Mustangs?)

Laminar flow wing had been originally visioned in the 1920s and by 1930s it was already a known thing. It's efficiency is today much debated and certainly a lot of other aircraft achieved same performance without laminar wings.

> 2) A special radiator construction, providing additional thrust (how can you imagine this?)

Easily. As with laminar wings this was a known effect already before the war.

As for some interesting details on the 109, it had a very interesting cooler arrangement that actually resembles very much that of the P-51. It happens that the coolers, which look like very small, are in fact embedded into the wings and have a very low wetted surface. Also they look like normal coolers which just dip into the airflow , but they are a bit more complex. The cooler is embedded in the wing so that a plate over the cooler would skin off the dirty boundary layer like in the P-51 cooler and let it pass , while using the "clean" air for cooling. This makes it possible to use less surface for cooling which means more speed. The similarities don't end here, just as in P-51 the cooler rear end has a plate designed to adjust the amount of air flowing through the cooler (it is opened and closed automatically or with manual override). The design of this flap seems quite the same as the one on P-51, which was designed to generate the "Meredith Effect". The Meredith Effect is actually a cooler acting like a jet engine. Jet engines are actually very simple, you have a compressor compressing air, fuel heating it and a nozzle turning the heat into momentum. In this case you have a cooler heating the air, the mouth of the cooler (and airspeed) compressing the air and the flap on the back working as a nozzle to convert heat to momentum. This effect could generate up to 300hp on the P-51 and it would in most cases (high speeds) almost zero out the drag of the cooler scoop.