Me 109 30mm weapon

[ibreh]

Hello all  

i was asked by to squadmember to look for the following data in a book i have and talked about. i posted it on our squadBB, but some said i shall post it here too. so lets go, i hope it is of interest for some of you  
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Hristo asked me to look for the weaponry , especially the 30mm, of the various 109 models. I have a book (german language) thats named „Die Deutsche Luftruestung 1933 - 1945" where all german war planes including prototypes and planned aircraft are written down with weaponry, engines and so on. Of course i cannot say wether it is correct in all regards or not. But this book is rewritten 5 times untill now because they were able to collect more and more information from the former allies since it´s first outcome, and i think it is a very serious information. There are no stories in, only data.
The following is what i found about the 109 with 30mm (i write down the standard types and the different „ruestsaetze" like gondolas and so on).
Me 109 G-6:
(first 109 where the 30mm is named)
engine DB 605 AM, AS, ASB, or ASD
weapons 2* MG 131 13mm, 1* MK 108 30mm

Me 109 G-6/R4
like G-6, plus 2*30mm MK 108 in gondolas, + GM 1 injection

Me 109 G-6/R6
like G-6 plus 2*20mm MG 151/20 in gondolas

Me 109 G-8
reconnaisance plane, only weaponry 1* MK 108

Me 109 G-10
engine DB 605 D (1435 hp)
weaponry 2* MG 131 13mm, 1* MK 108 30mm

Me 109 G-10/R6
like G-10 plus 2*20mm MG 151/20 in gondolas

there are some more G-6 and G-10 with added wingmounts, like rockets WGR 21. It seems that the G-6 and G-10 have allways 1*30mm MK108 in the prop, maybe some buildin 20mm because of shortage of MK108, as some squadfellows think??. The G-14 and G-16 only uses MG 151/20 20mm.

Me 109 H-1 (the H serie was very small in numbers, a so called "hoehenjaeger" (highaltitude fighter)build from the airframe of the former Me 109 F series
engine DB 601 R-1 with GM-1, larger wingspan
weaponry 2* MG 17 7,9mm , 1* MK 108 30mm

Me 109 K-0 (build from 11/44 on)
engine DB 605 D with GM-1
weaponry 2* MG 151 15mm, 1* MK 108 30mm

Me 109 K-2,
engine DB 605 ASCM or DCM with MW-50 injection
weaponry like K-0

Me 109 K-4 same like K-2, but „Druckkabine" (sorry, dunno the english word, to translate it word by word it is pressure canopy , for hi altitude)

Me 109 K-6, small serie
engine DB 605 DCM
weaponry 2* MG 131 13mm, 3* MK 103 30mm (2 in wings, not in gondolas!!)

Me 109 K-8
engine same like K-6
weaponry 1* MK 103 30mm in nose, 2* MK 108 30mm in wings! (no gondolas !!)

Me 109 K-10, very limmited numbers
engine DB 605 L (1750hp)
weaponry 3* ;K 108 30mm (2 in wings)


so the MK 103 is only named for the K-6 and K-8, all others use the MK 108 .

difference between MK 103 and MK 108:

MK 103
length 2318 mm
weight 146 kg
rounds of fire 440/min
velocity 860m/sec
cartridgeweight 980g
shellweight 530g

MK 108
length 1057 mm
weight 58 kg
rounds of fire 660/min
velocity 520m/sec „later" 850m/sec (not mentioned when)
cartridgeweight 480g
shellweight 330g

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So, if you have questions or i can see for some other things in this book just tell me. But i can only look for it, i am no expert on this.
Plus i want to beg your pardon for my bad english  

cu all


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ibreh
III./JG2 Richthofen
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[Gunthr]

Thanks Ibreh, that is interesting.   Do you know where I could find a discussion of the relative differences in performance and combat effectiveness amoung the Aces High 109 varients?

Gunthr
332nd Flying Mongrels

[RAM]

Seeing that data I must ask again, if K-4 109s were fitted with Mg151/15, then the G10 isnt by far as good as a 109K4.

Seems also (Hristo posted this data in JG-2 forum) that by late 1944, Mk108 cannons had much improved powder and propellant in the 30mm cartdridge, leading to a much higher muzzle velocity, in order of 800 M/s...if this is truth then G10's Mk108 must have much better ballistics than it has right now (in fact, as it has a similar Muzzle speed that Hispano 20mm, it MUST have much better ballistics that it, as it is a much heavier round, isnt it?  )

I'm quite interested in this, because 15mm cannons had much better hit power than 13mm MGs, and a hi-speed 30mm round can finish the F4U1-C Headon Campaign...

[ibreh]

no gunthr, i don´t know such a discussion site or something like this, sorry.

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ibreh
III./JG2 Richthofen
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[HABICHT]

hiya 109 fans
like you know, i'm a big 109 fan and often
angry about the flight model in "allied"
simulations.
but i have some facts to say:
i know there are DRAWINGS of weapon installation in the web and in historic books.
there you see 109 k6, k8 & k10 with the MK108
built in wings. but there are although many drawings , showing the MK108 in gondolars.
i know/found NO real PIC showing the cannons in wings.
saw a 109 in real live VERY near, looked into the 30mm hole in th spinner, cool.
but i must say, THERE were NO room for a mk108 with ammunition in these small wings.
why should be room for a MK and not for a MG151/20?? which were used in gondolars?
the wing of the late 109's even needed a
little bump to retract the gear completely.
only inside winged cannon 109 i know and i
saw real pictures,is gallands personal modified 109F6 with 2x MGFF in wings.

for all pilots with less historic knowledge:
i want the Mg 213C or MK 213 cannons.
MG213c=20mm with 1700 rounds per minute :-)
MK213 =30mm with 1500 rounds per minute :-))

the Mg/MK 213 was a the firts developed
revolver cannon, like all modern fighters have on. it was ready for combat, but befor
war ended only installed in one Bf110.


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JG2 "Richthofen"

[This message has been edited by HABICHT (edited 04-03-2000).]

[Hristo]

MG 151 as cowl guns on K varients ? Again ? Is it just William Green, or some other source ?

Ok, MK 103 only in K-6 and K-8, small series aircraft. Also pretty hard to believe a MK 103 in 109 wings, hmmm.


What caught my attention is such a big difference between initial velocity of “early” and “late” MK 108 rounds of 60 % !!

Was it possible at all in the same gun ? How was it achieved, by smaller/lighter round, more propellant or … ?

Does anyone have more data on this particular subject ?

[Vermillion]

Hristo, one problem with Green's book is that for many years it was considered "the best" source on Luftwaffe aircraft. And many authors in the following years, didn't do their own research, and subsequently have the same MG151 15mm cannon error as Green.

On the 60% increase in velocity of the 30mm cannon.  

There are two ways I know of increasing muzzle velocity 1.) decreasing the weight of the round  or 2.) increasing the presure inside the barrel (more force on the projectile).  This goes back to the basic physics equation of velocity = force \ mass

If you decrease the size of the projectile, you get a trade off in increased velocity, but decreased impact mass and less explosive in the shell.

The second way, is possible, by increasing propellant, a more efficent propellant, and or a longer barrel.  But it also means a much higher manufacturing quality of the metals used, and the weapon manufacturing itself. If not, you get a gun that tends to blow itself up.

Even if you use both methods in conjunction, I find a 60% increase hard to swallow.

My guess is that someone is again mixing up the 30mm Mk108, with the much different and much heavier 30mm Mk103. Which has a muzzle velocity in the 860m/s range.

Now, I have seen sources that say a very late war version of Mk108 was planned/available that increased rate of fire, up to about 850 rpm, instead of the more traditional 600 rpm, which is much more believeable than increasing the velocity by that much.

Just my own opinons.


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Vermillion
**MOL**, Men of Leisure
Carpe Jugulum
"Real Men fly Radials, Nancy Boys fly Spitfires"

[This message has been edited by Vermillion (edited 04-03-2000).]

[ibreh]

sorry verm, hristo and all others!!
it IS round of fire ("schussfolge")that was increased from 660 to 850 "later" and not velocity.
sorry, my fault by typing!  
Habicht, these are drawings with the 30mm MK in this book too, no photo´s, maybe the same drawings you know. and in the drawing of the K-6 it looks more like 3 MK 108, and not as given in text the page before 3 MK 103. the drawing of the K-8 shows clearly nose MK 103, wings MK 108.


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ibreh
III./JG2 Richthofen
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[Hristo]

Thanks, Ibreh, for clearing this  

Who knows, maybe we can live with increased RoF too.

[HABICHT]

cc ibreh,
but i wanted to say, that the mk103 and the
mk 108 are much to big with ammunitinon for
the 109 wing. they even had big problembs to fit the MK's into a much bigger 190 wing.
cc, i know the drawings. but i have books,
saying Mk in wings others said in gondolars.
even for the mg151/20 the 109 wing was to small. the mgff, galland used in his F6 were
smaller than the mg151/20. look at the earlier 190er. the mgff's are in the outer wing, where less room was. the mg151 was nearly the fuselage where wing was bigger. at later 190 with 4xmg151/20, there where bumps at the 151/20 position on & under the 190 wings.
i thing thouse drawings of the K6,8,10 where
never realized. there are existing although
enough drawings of the k6 with gondolars.

but again, nothing is 100% for sure.

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JG2 "Richthofen"

[This message has been edited by HABICHT (edited 04-03-2000).]

[flakbait]

I hate to burst your bubble, but the 109 G8 only had 2*M.G. 131 machine guns. No Mk.108, no M.G. 151/20, no cannons at all. It was a recon aircraft so they lost the cannons, lightened the gross weight a bit, and added cameras. They also added an MW-50 boost.

Also, the R4 for the 109 was never produced. The R6 was the 20mm gondolas, and the R4 was supposed to be attached in the same manner.
I don't know why, but the R4 never made it past testing stages.

No 109 variant up to the G6 had a 30 mike-mike cannon. The G-10 had one as optional armament that had to be installed in either rear areas or at the factory. I know this from several books, plus the written flight logs of my grand dad. I thought Japanese were records freaks; grand dad put them to shame!

Here's an excerpt from his flight log, dated 12-7-44 when he flew a 109 G-10 armed with a factory-fitted Mk.-108:

"Fired at Boeing [B-17] on the right wing of the kette. Position of attack was head on. Witnessed strikes on the top section of cockpit, upper weapon turret, and back to the tail section. Trailing wing man witnessed tail seperation from aircraft, also reported over radio large holes in top sections of the Boeing.

Repeat attack pass was made 21 minutes after first. Fired until the 30 millimeter stopped. Approx. 21 rounds struck Boeing lead in the cockpit area, right wing, No. 3 and 4 engines destroyed and on fire. Trailing aircraft made pass on right wing, seperating it from the Boeing."

His after action report reads something like this [his handwriting needs work; it's hard to read]:

"...Total enemy planes destroyed counted at 6. 108 cannon caused catistrauphic damage. Pilot bailed out, abandoning aircraft..."


After I asked him about the jamm, he told me what happened:

"That cannon was a mess! It tried to double chamber which blew up the round already in the weapon. My oil light came on, the whole airplane jerked hard and up, I thought I was a dead man! I decided to loose some altitude and bail out, which I did at 6,800 meters I think.

When I got back to the field, my ground crew had found the wreckage and brought it back. The cannon round didn't explode, the powder in the casing did. He said 'If that thing had really blown we would of picked pieces of you from the trees!'. I don't doubt him. From then on I only flew the G6 with the 20mm cannon. I flew a K4 model for a few weeks, but I almost didn't make it back because of that cannon."


Anyway we could model jamming or a double feed? Or would you rather not share my grand dad's experiences?  

Flakbait

[funked]

Ibreh, thanks for the info.  That makes more sense that the rate of fire was increased rather than muzzle velocity.

As far as I know the MG 151/15 did not appear in the K-4.

K-6 and K-8 were not produced.

[humble]

flakbait,

Very interesting reading, thanks for sharing it. Was your grand dad one of the "old hands" or did he only fly late in the war. I'm curious if he could shed any light on the relative handling/speed of the G6 to K4 vs the pony. Also curious if he flew 190's at all.

[SnakeEyes]

Yah, speed against the Stang would be real interesting.  I hear that the Luftwaffe and the USAAF used to head-out to the ol' Aerodrome on the weekends and drag race 'em against each other...

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SnakeEyes
o-o-o-
=4th Fighter Group=

[Toad]

 

Originally posted by RAM:
(in fact, as it has a similar Muzzle speed that Hispano 20mm, it MUST have much better ballistics that it, as it is a much heavier round, isnt it?    )

Ram, what do you consider "better ballistics"?

If you shoot a heavy and a light projectile of the same ballistic coefficient <and here we assume here that a 20mm Hispano and the 30mm German 108 have a close BC...which probably isn't true at all> the light projectile will go farther with less drop. As Verm mentioned, it's the old Force = Mass x Acceleration equation, basically.

I don't have the Ballistic Coefficients for either projectile and these numbers are vitally important in determining ballistic performance.

But, if they were close, initially the heavy one would have more muzzle energy and would retain that advantage out to some distance. At some point tho, the loss of speed compared to the lighter projectile will likely tip the energy balance towards the lighter projectile. Generally this would be at the "longer" ranges of the total range.

So, how are you defining "better?" Range? Drop? Muzzle Energy? Downrange Energy? Muzzle Velocity? Downrange Velocity? Or,as they say in the ads, "A combination of ingredients?"

Considering that these are explosive rounds in any event, it may be that kinetic energy isn't as large a factor as the explosive nature of the round in question.

Just some things to think about.    

Flakbait:

MORE! MORE!

I love reading those first person accounts! Sounds like you have a real treasure there, especially if he is still amongst us.

My regards to him and you!

Thanks!


[This message has been edited by Toad (edited 04-03-2000).]