German data on Mine shells to shoot down 4-engined bombers

[avin]

Wilbus,

I have no reason to believe Galland's statement was independently derived, and can't imagine how he would have derived it. Apart from potential one hit killers like the 30mm and 37mm, the only estimate for hits/kill I've seen is Sakai's P39 shootdown with 4 20mm shells - and the circumstances around this one were very unusual (he saw 4 puffs, and only 4 shells were fired).

I personally can't derive such an estimate from the main arena in a flight sim without the "score" hit percentage. It would be impressive to see a study done by an ace in the real deal.

I would imagine Galland was quoting the results of LW tests such as the one I quoted. These tests don't translate into real life hits/kill in a straightforward way, as I once thought.

Unless you know otherwise?

avin


[This message has been edited by avin (edited 04-10-2001).]

[janneh]

going little OT, but after luftwaffe staff began to record and research fighter statistics they found out incredible things from Hans-Joachim Marseille "Star of Africa";
Guenther Rall:"We found that Marseille needed an average on of only fifteen (15) bullets per kill" !!!

On one sortie he scored 6 kills and used less than half of his 109 ammo !
Of course Marseille was exceptional pilot and so this should not be generalized, but just think... 6 kills in 109 and more than half ammo left ! Not any rubber bullets, tho.
He flew 109E-4 ? and/or 109F-4 ? anyone ?

[edit]From "Horrido ! Fighter aces of the Luftwaffe": The wartime combat reports of the Luftwaffe fighter pilot were highly detailed. Every evening you had this business to go through. Witness, air witness, ground witness, your account of the combat, the type of enemy aircraft, the kind of ammunition you fired, the armament of your aircraft, and how many rounds of ammunition. These reports were nuisance to us, but when I was on the staff of Galland I saw how valuable they could sometimes be" by Guenther Rall.

So all were recorded really accurately.


[This message has been edited by janneh (edited 04-10-2001).]

[Karl]

Hi avin,

2cm M-Geschosspatrone 151
Patronengewicht: 183g
Geschossgewicht:  92g
Geschossfüllung:  18,6gr Nitropenta.

< Edited >

The Documets are right but you have to understand it. They say, to get down a bomber, you need 18 20mm or 4x30mm shells.
This based on calculation, how many Explosivfilling you get on the target.
You have to read all documents. Hm, how i can tell you. lets see .
Here is a small Table from a Mauser research Document.
----------------------------------------
Weapon   : 500m to target: 1000m to target
----------------------------------------
MG151/20 : 11 x 18 = 198 : 22 x 18 = 594
MK108    : 12 x  4 =  48 : 30 x  4 = 120
MK103    : 10 x  4 =  40 : 26 x  4 = 104
----------------------------------------

Now the story.

The MG151 has to fire 198 shells to get 18 statistical hits on a 500m target.
The MK108 has to fire 48 shells to get 4 statistical hits on a 500m target.
All based on 10% hitratio and and reviewed
with groundtest on bomber and Guncams.
I can show you much more Charts original from mauser.
< edited >

Karl  

[This message has been edited by Karl (edited 04-13-2001).]

[This message has been edited by Karl (edited 04-13-2001).]

[buile]

Karl,

Ignore the part of Avin's post that says:  

it does mean that the oft-quoted 18-22 20mm shells to down a heavy bomber is wrong. It took 45 shells.

And lets move the discussion closer to what we see as an interesting issue.  I think we can generally accept the number of M-geschoss as shown in the tests, but, the main question becomes: how do we get 18 hits of 20mm M-geschoss in a operational situation if not all the rounds on the belt are M-geschoss?  

We'd have to score more hits of all the types in the belt before we approach 18 hits of purely M-geschoss.  If we have non-M-geschoss in the belting, how does this affect the average numbers of rounds it takes to effect a shoot-down?  I would suspect it goes up some since those rounds contains less explosive.  But how much higher can we suspect that average to become (maybe this gets into the realm of putting angels on the head of a pin)?  The other rounds are usually HE/I correct?  Does the incendiary effect "hold its own" when it comes to starting fires that leads to the shoot down?    

Were other tests done using all the rounds present on an operational belting as opposed to a purely M-geschoss loadout?  Where does the number 22 come from (it seems quoted so often) as opposed to this document specifying 18?  Do we know where these other tests came from?

buile-

[avin]

Gerzzz,

I've tracked down the original document I quoted from. My German is very poor, but that 18 Mine shells indeed appears to be a theoretical estimate, as hooligan (and buile) explained already.

 

Gerzzz wrote:
The MG151 has to fire 198 shells to get 18 statistical hits on a 500m target.
The MK108 has to fire 48 shells to get 4 statistical hits on a 500m target.
All based on 5-7% hitratio and and reviewed

I think you'll find that 18 hits out of 198, and 4 hits out of 48, is not a 5-7% hit ratio.

avin


[This message has been edited by avin (edited 04-13-2001).]

[Hooligan]

Gerzzz:

Is that really you?  I would have never guessed it from the tone  .

I am terribly interested in finding out exactly what light the Mauser documents can shed on this particular question.  I don't know where Avin's document comes from but it does seem to quite clearly state that 18 Minengeschoss (not just 20mm but specifically M-shells) are required.  Do the Mauser documents make any similarly specific statements about number and type of rounds?

Hooligan

[Tony Williams]

I have seen a Luftwaffe figure of only 2% of rounds fired actually hitting the target.

As a matter of interest, I have also read that the Polish air force reckons 6% hits for their MiG-29s, and a Tornado F3 pilot tells me that a really good shot can land 20% of shots fired on a towed drogue target (nice and steady, with a radar reflector to help the radar gunsight.....)

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/  

[Karl]

edited

[This message has been edited by Karl (edited 04-13-2001).]

[buile]

 

appears to be a theoretical estimate. hooligan (and buile) explained this to me already

Theoretical in so far as conducting tests presumably against static targets like Hoolign said.  However, the results are further bolstered by examination of gun camera apparently from operational use.

They are using a nearly 10% hit rate as determined from guncamera of the "better" pilots.

buile-

[avin]

[edit] No need to keep this up.

[This message has been edited by avin (edited 04-12-2001).]

[buile]

I suggest we put the issue of tone in this thread behind us.  Lets start with a clean slate, please, and ignore the tone issue unless:

a: we decide to join a private discussion.

b: tone becomes a problem in the private discussion.

I am interested in the discussion here, and would rather not have this issue become a barrier to examining it.

buile-

[Vermillion]

I'm interested in any discussions on these types of issues, but I'm way too busy to start checking yet another BBS or mailing list each day.

------------------
Vermillion
**MOL**, Men of Leisure

[Karl]

Hi,

i have translating some parts. Sorry about my lack of english. But i hope you understand it.
--------------------------------------------
Forderung an die Entwickung von FLiegerbordwaffen.

          Bühler, Berlin,

1) based on the expierience we have in the last month of war,
   we need only 2 kinds of Ammo for destroying flying targets.
 
  1.1)  Geschosse mit Brandwirkung
        ( Projectiles with fire effect)
  1.2)  Geschosse mit Minenwirkung  oder Gasschlagwirkung
        (Projectiles with mine effect or muzzle blast effect)
         
 
 Projectiles with major penetration values are not needed, while
 the airia of armored surfaces of the plane is very small. So we dont
 need further development for Ammo with higher V0 to penetrade Amor.

 
 We need only the V0 to get the Ammo to the target and the correct calculated
 Ignitiontime with delay.

 ...
 Projectiles with fire effect is very usefull against the B17. The B17 has hughe
 Fuel tanks in the wings.  On the other side the B24 has there fuel tank placed in
 the Fuselage and only small tanks in the wing. Here works the "Brandmunition" with
 less effect.
 Projectiles with Mine effect / muzzle blast effect works on both planes good.
 
 ...

2) possebility of the probability of hit ( Thats right ? oha )

  The probability of hits is based on:

   2.1) Projectile flying time  ( V0 )
   2.2) Form value of the projectile
   2.3) Rate of fire
   2.4) Weapon dispersion
   2.5) Stability of the airplane ( effect the Hitrate of the pilot )
   2.6) % Hitrate of the pilot ( german word "Abkommengenauigkeit" )

  If we do a calculation about a special muntion , how much Rounds we need
  to get hits, we will determine, that there is only a small different between
  high und low V0. The pilot need with the 3cm MK108 ( V0 = 505m/s ) at 500m Combatrange
  22 Rounds per hit and with the 3cm Mk108 ( V0 = 870m/s !! ) at the same range 19 rounds
  per hit. The same  calculation at a target distance 1000m  the  values are 57 and 51
  rounds per hit. We calculated this based on a 10% Abkommengenauigkeit >8)
  ( Pilot hitrate ) reviewed from many "Frontfilmauswertung" ( Guncam ).
  Eine 95 prozentige Trefferwahrscheinlichkeit bei Gaußcher  Kreisverteilung der Schüsse ist dabei errechnet. " Hm hard to translating" ( 95% probability of hit during Gauss set distribution of the shots is thereby calculated.

  Numbers of needed Hits to get a 4 MOT Bomber down:

  --------------------------------------------------
  2cm   Minengeschoss, Sprengladung  18g, 18 Treffer
  3cm   Minengeschoss, Sprengladung  72g,  4 Treffer
  5cm   Minengeschoss, Sprengladung 350g,  1 Treffer
  5,5cm Minengeschoss, Sprengladung 420g,  1 Treffer
 
  --------------------------------------------------

  These values are as averaging value from GunCams and Tests determined.

-------------------------------- end.

The Document is much longer with much data.
Anyway, my resume of this is:

Yes, 4 30mm hits to get down a Bomber IS possible. BUT, you have to hit at the right places. Not always 4 hits causing a destroyed Bomber. The numbers are average.

Karl


[This message has been edited by Karl (edited 04-13-2001).]

[This message has been edited by Karl (edited 04-13-2001).]

[Karl]

Need more data ?

Karl

[buile]

The question now becomes (in relation to the 20mm): if the pilots are not firing all M-geschoss from their guns, how does this change the average number of hits to effect a shoot-down?  Since there is less HE in the non-Mine rounds, we'd expect the number to rise.  How high can we expect the number to rise?

Should we begin looking at the issue in relation to the gram weight of explosive needed like the way Avin was pondering?  Or, does the different effects of the ammunition (incendiary vs pressure effect) throw that off (not linearly related)?  By how much can we expect?

That's why we're wondering about the primary source for the oft-quoted "22 average hits" to see how that number was arrived at.  Or, what about any pilots who studied the number of hits they took (with an operational belting).

 

Yes, 4 30mm hits to get down a Bomber IS possible. BUT, you have to hit at the right places. Not always 4 hits causing a destroyed Bomber. The numbers are average.

Yes, the number is an average, but i wouldnt get *overly* strict on the placement of those rounds.  You dont the all 18 hits to be in the right place, you need, on average, 18 hits to get the subset needed into the right places.  That's what i think.  Otherwise, you'd say you need an average of 3 20mm hits to down a bomber (but all 3 hits must be to the cockpit).  It's: how many hits do you need on average to get enough in the right places for a shoot down?  18 M-geschoss.  Okay, now how many with a normal belting?  

buile-

[This message has been edited by buile (edited 04-13-2001).]