Me262 vs. P-80

Originally Posted by acesman

Not to imply that the Me-262 did not hold its own in air combat, but the Luftwaffe after 1943 was so grossly outnumbered that no individual skill, technology or bravery could reverse the outcome. Me-262's were especially targeted on their takeoff or landing, if possible, and the USAAF put a premium on harassing the airfields used for jets.

The Luftwaffe' was not grossly outnumbered until late Spring 1944, when during Big Week they lost around 1/3rd of their aircraft and 1/5th of their pilots. Also, the P-51's and a few P-38's were the only planes able to reach them, and those were sorely outnumbered at the time. The German's goofed by spreading out their fighters too much, allowing the comparatively small number of US fighters to tackle them at fairly even odds.

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Lunatic

[delcyros]

I have checked the waeponry again. A layout with 4-6 MG 151/15 as suggested by Lunatic would be excellent for a jet vs. jet fight, agreed. But it would be worse on interceptions against heavy bombers.
I would choose a weaponry of three MK 103/30 mm with 80 rounds each. The weight would be no problem if the Me-262 sacrifice half of it´s armor plates. This would remove the forward plates, but not the cockpit armor. With 80 rounds it would have enough ammo for 12 seconds (instead of 10 for the P-80). The trajectory of the Mk 103 would be excellent for high speed dogfights. It still has only a combined speed of fire of 20-22 shots per second, compared to 120 for the P-80. That are 6 shots fired by the P-80 and a single fired by the Messerschmidt, while the chance to hit would be roughly the same. I regard a single 30 mm/Mk103 hit far more destructive than 6 0.50 M3 hits. Such a modified weaponry would postively effect interception duties and ground attacks also.

First off, 3 x MK103's weigh 932 lbs - and the ammo is heavy too. Conversly, 6 x .50's weigh 396 lbs, and the ammo is relatively light. So you are putting roughly 2.5x the weight into the nose of the 262, this would drastically effect performance, you are roughly doubling the gun/ammo weight as compared to the MK108's.

Secondly, the most common type of firing solution in high speed combat is a leading deflection shot. In this kind of shot, you lay down fire in front of your target and let him fly through the stream. But, with only about 20 rps in that stream, the odds of the target flying through it w/o taking any hits are quite high. Gunnery against fast fighter targets using the MK103, with it's 420 rpm RoF would be very difficult.

Thirdly, the recoil from three MK103's would be quite high, making gunner even more difficult.

Forth, for attacking bombers with an MG151/15 armed Me262, it seems to me the underwing rockets are the perfect solution. This way you get the best of both worlds. Guns suitable for fighting fighters, rockets to take out heavy bombers.

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Lunatic

[delcyros]

The weight would never increase up to twice the weight of a MK 108 equipped plane:
Me-262 A1: 4 MK 108 (232 Kg) + 360 rounds (220 Kg) + 282 Kg armor=
734 Kg (100%)
Me-262 mod: 3 MK 103 (426 Kg) + 240 rounds (216 Kg) + 140 Kg reduced armor = 782 Kg (106,5%)

The removal of it´s nose armor is necessary because of the change of it´s center of weight. Cockpit armor would be about the same. With these numbers in mind I see no justification for a "drastic" performance change thanks to a "doubling of gun/ammo weight" compared to a Mk108 equipped plane.
A MG 151/15 equipped plane would be lighter. Total weight including ammo for 12 seconds would be:
6 MG 151 (288 Kg) + 840 rounds (172 Kg) + full armor (282 Kg) = 742 Kg (101 %)
The nose armor cannot be reduced, since the MG 151/15 have a shorter and much lighter barrel (or additional weight has to be put in the nose).
20-22 rps are about the same of a single 0.50 M3. I regard that rate of fire enough. A higher rate of fire would increase the probability of multiple hits on a certain space in a given time drastic. But a single Mk 103 hit is enough to get a P-80 kill (except maybe for wingtip hits or duds). The velocity and trajectory of a MK 103 shell is amazing, making aiming much easier (as shown for the 0.50 M3 by You). The recoil would be a problem, agreed. However, the MK 103 doesn´t blind that much (compared to 4 MK 108 with high rof). Both weapon layouts (Mg 151/15 and MK 103) are better than the original one, I think.

The ballistics of the Mk103, firing the Ausf. A mine round, were not as good as those of the .50 BMG. The MK103 hits mach 1.5 (sea level) at approximately 550 meters, the .50 BMG at ~900 meters. The ballistic shape of the Ausf. A mine rounds was quite poor. Even the Ausf B rounds (where these available for the MK103?) shape is not that good.

With such a low volume of fire, the pilot could not afford to fire at long range. It would eat up his limited ammo supply for a low chance of scoring a hit. If he cannot afford to fire at long range, why carry the MK103 over the MK108?

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Lunatic

[delcyros]

I do not question the gerneral superiority of the 0.50 M3 compared to the MK 103 or MK 108 equipped plane in a dogfight situation. But I tried to underline, that MK 103 weaponry (as suggested by OKL on 21st. of december ´44) would make the jet probably a better one.
Hits beyond 500 m were not very common, the usual shooting distance was under 300 m (which also was the limit range for MK 108, thanks to it´s poor ballistics). A MK 103 could increase the range a lot, that would be very good at ground attacks and interceptions. On the other hand this weapon layout would also work positively at high speed dogfights in close to middle range. The ammo would allow to fire the guns two seconds more:
Me-262 mod. : 3 x MK 103 (80 rounds= about 12 seconds)
Me-262 A1: 2 x MK108(80 rounds=about 8 sec) + 2 x MK 108 (100 rounds= about 10 sec.)
The advantage of a much higher rof (compared to MK 103)would last for 8 seconds only (in which it has doubled total rof of around 40 rps) the next two seconds (8-10) the total rof would be the same (around 20 rps) and in the last two seconds the MK 108 equipped Me-262 would be silenced, while the MK 103 equipped one could still fire at 20 rps. In that view the Me-262 A1 would run out of ammo much sooner than the MK 103 equipped one. And I think this would allow the pilot to fire at longer ranges and against different targets with equally chances of succes: Bombers, vehicles, fighters, shipping, light and medium tanks. This may justify the use of MK 103 over MK 108.

You are not factoring in the negative effects of recoil at all. Each Mk103 has more than 3 times the kinetic energy of the MK108. When you factor in the gas effect, it is probably over 4 times the recoil. Three MK103's would have between 2.5 and 3 times the recoil energy of four MK108's. And because the recoil is spread out across half as many pulses per second, it's going to be much more severe. It's going to be a lot harder to hold your aim with MK103's than with MK108's. They'd probably only be able to be used for very short bursts (~3 rounds per gun?).

Two seconds additional fire time is not very significant, especially when those two seconds involve half the volume of fire.

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Lunatic

[delcyros]

I agree in the problem with a higher kinetic energy. While the Me-262 was a pretty stable gunplatform at high speeds (allowing an increasement of up to six (!) MK 108 weapons into the nose or a BK 5 or MK 214 gun on a few planes), it would clearly suffer in it´s stability by firing three MK 103. However, all guns are in the nose, beeing close to the energy axes, this would greatly reduce the effects of the heavy recoil. But the plane still sufferd from heavy blinding. That´s why it always could fire a very few rounds per attack pass, only. (fine aiming becomes impossible with the blinding of four MK 10 In this way I see problems with both weapons making prolonged aiming very difficult for the pilot. While the high rof of the MK 108 would serve well for 8 seconds, the MK 103 with lower rof would serve also well in another way: The flat trajectory and the high velocity makes aiming quite easy (compared to a MK 10. The probability of hits would be much better. And the MK 103 still has it´s advantage in general prurose.

Originally Posted by delcyros

I agree in the problem with a higher kinetic energy. While the Me-262 was a pretty stable gunplatform at high speeds (allowing an increasement of up to six (!) MK 108 weapons into the nose or a BK 5 or MK 214 gun on a few planes), it would clearly suffer in it´s stability by firing three MK 103. However, all guns are in the nose, beeing close to the energy axes, this would greatly reduce the effects of the heavy recoil. But the plane still sufferd from heavy blinding. That´s why it always could fire a very few rounds per attack pass, only. (fine aiming becomes impossible with the blinding of four MK 10 In this way I see problems with both weapons making prolonged aiming very difficult for the pilot. While the high rof of the MK 108 would serve well for 8 seconds, the MK 103 with lower rof would serve also well in another way: The flat trajectory and the high velocity makes aiming quite easy (compared to a MK 10. The probability of hits would be much better. And the MK 103 still has it´s advantage in general prurose.

Again you are missing the point about the recoil pulses. Even if you added enough MK108's to have equal recoil energy to the MK103, it would not be as detrimental to aiming because the recoil energy is much more concentrated. In air-to-air combat, it is very hard to score any hits with a weapon that can fire only very short bursts - espeically with only a reflector gunsight to aim with.

As for the blinding effect, I have to wonder why the Germans didn't redesign the 262 nose such that they could mount the guns on the bottom.

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Lunatic

[delcyros]

I simply have no sources regarding the recoil energy of different weapons. All remains estimation (for me), but I would like to see some datas, maybe You can help? Yes, it sounds silly to mount heavy guns in the upper part of the nose. The nose gear took a great deal of space and because of the nose geometry I doubt that four MK 108 could be mounted on the botton, MG 151 and MK 103 are more unprobable because of their longer barrels. Maybe two single MK 108, mounted on each side of the gear are possible? The soviets have tried to bring two 23 mm Shvak and a single 37 mm gun into the nose of their Suchoi -"Me-262"-modification. It proved to be a very stable gun platform, but I don´t know about the recoil energy of these weapons, too.
Short bursts are not unlethal, but remains for experienced pilots, exclusively. Most german Experten preferred a heavy cannon armement over smaller calibres with higher rof.

Originally Posted by delcyros

I simply have no sources regarding the recoil energy of different weapons. All remains estimation (for me), but I would like to see some datas, maybe You can help? Yes, it sounds silly to mount heavy guns in the upper part of the nose. The nose gear took a great deal of space and because of the nose geometry I doubt that four MK 108 could be mounted on the botton, MG 151 and MK 103 are more unprobable because of their longer barrels. Maybe two single MK 108, mounted on each side of the gear are possible? The soviets have tried to bring two 23 mm Shvak and a single 37 mm gun into the nose of their Suchoi -"Me-262"-modification. It proved to be a very stable gun platform, but I don´t know about the recoil energy of these weapons, too.
Short bursts are not unlethal, but remains for experienced pilots, exclusively. Most german Experten preferred a heavy cannon armement over smaller calibres with higher rof.

Yes, but by "heavy cannon armament" they meant the MK108, not the MK103.

Recoil energy is the same as the round energy plus perhaps another 10-20% for the gas effect which is from any unexpended propellent power as the round leaves the barrel. So you can figure the recoil is a little more than the number of joules of ke listed in many sources. For the MK103, this is a little more than 3x that of the MK108.

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Lunatic

[delcyros]

Thanks for the informations. After what I have read, the Fw-190 A5 / U11 had an armement of 2 engine cooling mounted MG (MG 17?), 2 MG 151/20 in the wing roots and two additional MK 103 under the outer wing. The recoil pulses made the weapon nealy useles, so only a very few Fw-190 have been refitted in this way. The total recoil energy is very close to a Me-262 (MK-103 modified), but the excentric fitting in the outer wings rendered the Fw-190 weapons nearly useless. Would it be different if the recoil energy pulses are located closer to the energy axes as in a Me-262?
There were a few Me-262 equipped with even heavier weapons, like single BK 5 and MK 114. These weapons are mounted in the nose, also. They do have a comparable total recoil energy (the BK 5 a little less, the MK 114 more...) and an even worse recoil pulse. However, the Me-262 seems to be a very stable gun platform, since the main problem in this weaponry was -again- the immense blinding of such heavy weapons (beside of a tactical use). The total recoil energy of a MK 103 equipped plane would be doubled, compared to a MK-108 equipped plane. However, the energy pulse would be more concentrated, as you pointed out. I think a structural reinforment of the weapon hardpoints in the nose is necessary to deal with the forces. Thus would probably increase the weight further. (a BK 5 need a total of 96 kg reinforcemt of the nose, so between 50 and 80 kg are needed?) You made a good point in this, Lunatic.

Originally Posted by delcyros

Thanks for the informations. After what I have read, the Fw-190 A5 / U11 had an armement of 2 engine cooling mounted MG (MG 17?), 2 MG 151/20 in the wing roots and two additional MK 103 under the outer wing. The recoil pulses made the weapon nealy useles, so only a very few Fw-190 have been refitted in this way. The total recoil energy is very close to a Me-262 (MK-103 modified), but the excentric fitting in the outer wings rendered the Fw-190 weapons nearly useless. Would it be different if the recoil energy pulses are located closer to the energy axes as in a Me-262?
There were a few Me-262 equipped with even heavier weapons, like single BK 5 and MK 114. These weapons are mounted in the nose, also. They do have a comparable total recoil energy (the BK 5 a little less, the MK 114 more...) and an even worse recoil pulse. However, the Me-262 seems to be a very stable gun platform, since the main problem in this weaponry was -again- the immense blinding of such heavy weapons (beside of a tactical use). The total recoil energy of a MK 103 equipped plane would be doubled, compared to a MK-108 equipped plane. However, the energy pulse would be more concentrated, as you pointed out. I think a structural reinforment of the weapon hardpoints in the nose is necessary to deal with the forces. Thus would probably increase the weight further. (a BK 5 need a total of 96 kg reinforcemt of the nose, so between 50 and 80 kg are needed?) You made a good point in this, Lunatic.

Thank you. I've actually studied this before. A long time ago I calculated that each round coming out the pair of Ho155's on the Ki-84-1c would slow the plane approximately 11 mph. Such huge recoil forces are a real issue for effective weaponry in aircraft.

What Germany really needed was something in the 25 mm class, firing mine-type ammo (~40 grams/round) at decent velocity (750 m/s?) and decent RoF (750 rpm?). 30mm were fine for bombers but not really well suited for dogfighting, and it was hard to carry enough ammo. Four 25mm guns of the nature described above would deliver enough HE to down bombers, and enough volume of fire and velocity to be effective against fighters.

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Lunatic

[delcyros]

25mm would be interesting. But are you sure with a ~40 g/round? Even the MG 151/15 had 72g/round (MG 151/20 ~112 g/round). The blast effects of a 40 g mine round would be minimal. 25 mm and usual cartridge length implies between 150 and 200 g/round or aren´t they?
In this way, the development of MG 213 B/20 mm could provide the best weaponry for the plane (and for all purposes). But it wasn´t avaiable in the timeframe of early-late 1945 in numbers. Even with them, the blinding of nose mounted guns (in the Me-262 way) would still make prolonged aiming difficult. However, the nose design looks really good

[FLYBOYJ]

I've had the opportunity to fly T-33s, with and without tip tanks, and although I'm no honcho fighter pilot (I wasn't even trained as a military pilot) but I could tell you I would take the P-80 any day based on what I saw on the T-33. Its easy to fly, manueverable and very forgiving. \/

I think the biggest advantage the P-80 would of had over the ME-262 is durability. As we know much of the 262 was steel and other non-strategic material. We knew that the engines only lasted a few hours. Even if the war went on a few months longer, if the ME-262 was available in numbers, and if the P-80 was deployed against it, I think the 262 would have been a maintenance logistical nightmare and would of been overwhelmed by vast numbers of P-80s that were more reliable, easier to maintain and operate! The amount of lead thrown at each other wouldn't of mattered if the ME-262 couldn't even get off the ground.