Luftwaffe fighter shot grouping

[Deleted member 68059]

It seems that several German aircraft had very poor lateral stability, in the case of the Me262, it appears to be probably related to the forced labour making them by that point in the war,
many had very poor stability and some excellent.

The 210/410 also appears to have had quite bad lateral (yaw) stability, which is interesting given its eventual role.

I wonder if the very good stability of the 110 "might" have had some impact on its arguably quite extended career - as late in the war,
the purpose of all these 2-engined aircraft (at least in daylight) was to make accurate pot-shots at ever increasing range from the bombers.

The documents above are translated to English post-war, and are from wartime German test analysis which concerned itself with the
impact on yaw stability with the shot grouping at 1000meters range.

 

[Greyman]

From a translated 1943 Italian document (originally written by the Germans?); Development of Sights for Fixed and Free Guns which detailed German efforts in this area up until that point.

Dispersion due to the aircraft itself is much greater. This has been experimentally determined by installing in a fighter aircraft a camera gun (all errors if a ballistic nature are thus cancelled out) and choosing the simplest form of attack, i.e. prolonged burst, exactly on the tail of a bomber aircraft on a straight course. In this form of attack the operations of aiming are very simple, as it is sufficient to sight slowly and fire only when it is certain that the target is centred in the sight.​

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The leading aces of the German Fighter Arm were chosen to carry out the experiments and camera gun tests were carried out for ranges of 500 m. and 1000 m.​

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The results were discouraging. The winner of the competition, Oberst Galland, got the best score with an 8% dispersion i.e. only 50% of the rounds at ranges of 500 and 1000 m. lay within circles of diameter 8 m. and 16 m. respectively.​

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Such inaccuracy is inevitable in air gunnery, since it is bound up with the instability and uncontrollability of the platform represented by our aircraft, which in the tests under consideration were the Me.109 and Me.110 i.e. two of the most manoeuvrable types of aircraft.​

For what it's worth British testing at the Gunnery Research Unit found that on average a pilot could hold his sight within 0.23 degrees (3ft at 250 yards) 50% of the time.

Compare that with 0.92 degrees of Galland -- a pilot certainly not representative of their average ...

 

[MIflyer]

I recall reading that the typical Luftwaffe pilot had about a 1% chance of doing fatal damage to a B-17 or B-24 on one pass. I wonder about the probability of he taking serious damage from the bombers' defensive fire on that pass. In any case, that inspired the larger caliber guns, 30MM and up for the German fighters.

The Me410 was experimentally equipped with a 57MM gun but they found that while theoretically could lob shells into bomber formations from outside the range of the machine guns, at that range they had almost no chance of hitting anything, and the gun tended to jam anyway.

 

[Deleted member 68059]

I recall reading that the typical Luftwaffe pilot had about a 1% chance of doing fatal damage to a B-17 or B-24 on one pass. I wonder about the probability of he taking serious damage from the bombers' defensive fire on that pass. In any case, that inspired the larger caliber guns, 30MM and up for the German fighters.

The Me410 was experimentally equipped with a 57MM gun but they found that while theoretically could lob shells into bomber formations from outside the range of the machine guns, at that range they had almost no chance of hitting anything, and the gun tended to jam anyway.

If the guncam footage is to be believed, then I`d say that despite these requirements on stability, the pilots who were sucessful killers closed in to point blank regardless.

According to US analysis, about 2 to 3 strikes from an Mk108 shell was typically fatal to a bomber. I have RAF photos from static range tests showing that one Mk108
round completely removes the whole tail of a Spitfire.

 

[Engineman]

High speed snaking was a common problem that could be worse with poor standards of construction. There were aerodynamic fixes that included thickened trailing edge of rudder. The Germans did use thin outward bent strips of alloy on the rudder of the 262 to help. Ultimately, powered controls and Yaw damping was the cure.

Eng

 

[MIflyer]

According to US analysis, about 2 to 3 strikes from an Mk108 shell was typically fatal to a bomber. I have RAF photos from static range tests showing that one Mk108
round completely removes the whole tail of a Spitfire.

Yes, the fact that a 30MM could do the job with just a couple of hits was seen as an answer to the 1% per pass kill probability of the 20MM equipped aircraft. I recall a Me-262 pilot saying that he would "strafe" the bombers by flying at them from the side and above rather than closing from the 6 o clock position. Spraying 30MM across a flight of bombers instead of focusing on a single aircraft had a better chance of shooting one or more down and probably greatly reduced the chance of being hit by defensive fire as well. What he wanted to do was hit the loaded bomb bay with a 30MM round, the secondary explosion destroying the aircraft. As described it sounds rather like the F-94's and F-89's of the 1950's making beam attacks on bombers with a spray of 2.75 in rockets.

Somewhere I have a picture of a Spitfire fuselage hit with a single 20MM round for a ground test. It opened up as if you had pulled back the peel on a banana.

 

[Thumpalumpacus]

The 210/410 also appears to have had quite bad lateral (yaw) stability, which is interesting given its eventual role.

I certainly remember reading somewhen along the line that the Me-210 was sidelined precisely because of its poor yaw characteristics. I can't vouch for that claim myself, so if it's inaccurate I'm happy to be corrected. But it was apparently quite unstable on that axis from what I've read.