Info on Me262 with the BIG gun in the nose

[KraziKanuK]

KG200 Adler? Never came across any 262s assigned to this LW unit.

[DerAdlerIstGelandet]

Excuse me you are correct, I meant EK 262. I have been reading a book on KG 200 and it that is why that came to my mind.

[Haztoys]

I know this is old ..But theres alot of take about BIG guns in aircraft the last day or so...So I dug this up if anyone cares

[HoHun]

Hi Haztoys,

>I know this is old ..But theres alot of take about BIG guns in aircraft the last day or so...So I dug this up if anyone cares

Regarding the merit of big guns, a German committee on 16.2.1945 prepared a comparison study of the anti-bomber batteries considered by the Luftwaffe at the time.

Their analysis was based on the finding that an average of 0.36 kg of explosives were required to bring down a heavy bomber.

They calcuated the weight of the ammunition required to bring down a heavy bomber for each weapon considered, based on an even 5% hit rate for each weapon.

Then they used 6 barrels for the 15 mm weapons, 4 barrels for the 20 mm weapons, 2 barrels for the 30 mm weapons and 1 barrel for everything bigger, and calculated total battery weight and firing time required for one kill.

Finally, they ranked the batteries according to the product of total weight and firing time for a kill. (If a battery was twice as heavy as another, but required only half the firing time, they were ranked equal that way, so that was just a simple way of making the results comparable).

The resulting ranking (by reciprocal ranking value, best is 100%):

30 mm MG 213/30 - 100%
30 mm MK 108 - 72.8%
55 mm MK 412 - 48.5%
55 mm MK 112 - 47%
20 mm MG 213/20 - 27.2%
20 mm MG 151/20 - 26.2%
30 mm MK 103 - 23%
55 mm MK 214 - 12.4%
15 mm MG 151/15 - 5.6%
50 mm BK 50 - 5.2%

It's worth noting that the different muzzle velocities of the various weapon were deliberately ignored for this study since the findings of this committee were that high-velocity weapons had a higher dispersion than low-velocity weapons so that they offered no practical improvement of hit chances.

The EZ 42 gun sight that was capable of taking trajectory drop into account was (based on combat experience) seen as a better way to increase combat range than increased muzzle velocities or larger calibres. For the MG 151/20, good results had been achieved at 800 m combat range.

The study accepted that the intercepors would inevitably have to spend some time in the range of the bombers' defensive fire, as can be seen by the high priority for short firing times, which would reduce the exposure to defensive fire.

Regards,

Henning (HoHun)

[johnbr]

Great info.

[HoHun]

Hi again,

>Regarding the merit of big guns, a German committee on 16.2.1945 prepared a comparison study of the anti-bomber batteries considered by the Luftwaffe at the time.

I just found another study, published in Luftfahrt International 15, that compares the low-velocity MK 108 battery installed in the Me 262 with a high-velocity battery consisting of 2 x MK 103 and 2 x MG 151 (15 mm).

However, in contrast to earlier studies, the target considers weapons effect against Mosquito-sized jet bombers capable of a 750 km/h top speed, which the authors figured the Allies might field in the future.

MK 108 and MK 103 were assumed to fire mine shells, while the MG 151/15 was assumed to fire incendiary ammunition for the purpose of the study.

With standard reflector sight:

At 400 m range, the MK 108 battery is superior to the MK 103/MG 151 battery for load angles of up to 30°.

At 600 m range, the same applies as at 400 m range.

At 800 m range, the absolute hit chances drops so low that neither battery can expect a kill with the available ammunition supply.

With EZ 42 computing sight:

If an EZ 42 computing sight is used, muzzle velocity becomes a minor concern. Accordingly, the MK 108 battery becomes even more effective in relation to the MK 103/MG 151 battery.

Regards,

Henning (HoHun)

[Civettone]

Henning ... you're the man!



Kris

[Denniss]

Why should they have used the 15 mm MG 151 for testing ? AFAIR they used the standard MG 151/20 but it was just called MG 151.

[HoHun]

Hi Denniss,

>Why should they have used the 15 mm MG 151 for testing ? AFAIR they used the standard MG 151/20 but it was just called MG 151.

The report actually specifies "15 mm" throughout. I assume this was due to the desire for a very high muzzle velocity - the MG 151/20 did not reach the high figures of the MG 151/15 in that regard.

Regards,

Henning (HoHun)

[drgondog]

Originally Posted by Erich

well it was one of those late war Luftwaffe experiments to make them still on the cutting edge till wars end over every other nationality.

It was a filure and was not going to be pressed further, the prescence of the successful R4M would be treated into mass production had 46 onward happened with a more controllable guided rocket system. Pulling jet mph off was not what the jet pilots wanted nor needed with the superiority in Allied fighters. From what I hae found the Mk 108's would have been pulled off in time and replaced by faster firing 2cm weapons with longer range and a slightly longer fuselage and streamlined canopy for speed and endurance

I always had the same feeling. Speculatively speaking a faster firing 20mm would have been a strong consideration. The 262s had a hard enough tome scoring with 30mm from close range with the closing speeds.

The 50mm (almost) reminds me of the 75mm gun in the modified B-25. It is only recently that the fire control systems work well placing a 105mm gun on target with the AC-130

[Crumpp]

At 400 m range, the MK 108 battery is superior

The Mk108 was an excellent air to air weapon given the targeting technology of the day.

If not the pinnacle of aircraft projectile weaponry in 1945, it was at least very close to it.

The Ta-152C schußwaffenanlage and the Bf-109G umrüstatz 4 schußwaffenanlage all give the Mk108 a point blank zero at 400m.

When one considers that the chances of landing lethal strikes plummets in the 100m from 400m-500m, the Mk 108 was an optimal design for the sights of the day.

According to an RAE study, the chance of landing a lethal hit with any gun system, drop from 55% at 400m to 13% at 500m with a non-CGS sight.

All the best,

Crumpp

[Crumpp]

The 262s had a hard enough tome scoring with 30mm from close range with the closing speeds.

Hi Bill,

They definately did have a very hard time scoring hits.

I tend to think that this is a consequence of the closure speeds and not the weapons. Short of a laser beam or the modern day lead based equivilent, a mini-gun, there is not a projective weapon system that would have faired any better in the 262 IMHO.

This was a problem of the jet age.

All the best,

Crumpp

[drgondog]

Originally Posted by Crumpp

Hi Bill,

They definately did have a very hard time scoring hits.

I tend to think that this is a consequence of the closure speeds and not the weapons. Short of a laser beam or the modern day lead based equivilent, a mini-gun, there is not a projective weapon system that would have faired any better in the 262 IMHO.

This was a problem of the jet age.

All the best,

Crumpp

I totally agree, and actually believe the fast firing, ballistically superior 20mm might have had an edge over the Mk103 or 108 30mm with EZ 42 gunsight. There is zero issue in my mind about superior killing capabilty of the 30mm over the 20mm..

My reasoning, not supported by any specific statistics, is that great ballistics and higher rate of combined fire should give the 262 a chance to start firing at 800 yards and close to 300 before having to make a decision about break.

I have no comprehension why the 262 was ever equipped for night fighting with all the issues about closing speeds on targets you can actually see in daylight...

[Erich]

simplicity really, even Kommando Welter had considered pulling the 4 3cm pieces and replacing them with the 2cm mauser as it was already proven effective with the Ju 88G-6 craft in bomber killing, the 262 then could of had a later or farther start in letting off it's cannon and yet having to place more rounds into the Allied craft the use of 2cm Minen was standard equipment by 1945 ~ HE and HE/I

as to closing speeds believe it or not the 262 was ideal for Mossie hunting, dive from above and then swoop up slightly and let go with the heavy cannon. Yes it was earmarked for the future to engage the slower 4 engines, that was the plan anyway ..... with the twin seater and all the goofy radar hardware in and out the twin seater and external twin drop fuel tanks was quite a bit slower overall than the single seat A-1a used by the 10./NJG 11

[Crumpp]

Hi Bill,

I think you would be absolutely right if our sighting technology was not the limitation.

It is my understanding that even with CGS sights; engagement ranges were still only practical in the vicinity of 400M-500M.

The only real improvement in aerial projectile weapons, the multi barrel electric cannon, did not exist. The next step in targeting innovation, the radar CGS, did not exist either. So within the limits of targeting technology, I don't think you could get a better weapon system than Mk108 in the Me262.

The weapon itself is immaterial as we are restricted by our ability to accurately target.

If all of our weapons show a similar ability to land hits due to sighting restrictions, we might as well make the hits we do get count.

Here is a portion from the German experience with the EZ40/42 program. The engagement ranges are typical:



Here is the RAE experience with CGS sights. While they do improve a pilots hit chances considerably, there effectiveness dropped steadily with range. At 400M-500M the chances of downing an aircraft were greater than a reflex sight but still not very good.




All the best,

Crumpp