remember the ju88 13mm debate?.....

[hazed-]

recently I purchased the 'Warplanes of the third reich' by william green and just out of interest I looked up the information on the JU88A-4 hoping to find some evidence of its armament and I was also interested to see if there was any other information we may have missed.

Interestingly 2 things immediately stood out. Heres a quote on the JU88A-4:

'The first Ju 88A-4s manufactured received the jump211F-1 engine pending availability of the definitive Jummo 211J, these being rated at 1,340 hp, for take-off, 1,35- hp at 820ft., and 1,060 hp at 17,000ft.Reletively few had been delivered before the jumo 211J became available for installation, and by this time considerable changes had been made in both defensive armament and crew protection as a result of experience gained by the Ju88A-equipped Kampfgruppen during the "Battle of Britain". Although the Ju88A had faired better than other Luftwaffe bombers participating in the epic action, its high diving speed enabling it to evade even the spitfire, combat attrition had been by no means inconsiderable. Thus, the defensive armament of the Ju88A-4 was markedly improved. The MG15 was replaced by the far superior MG81 of similar calibre, and several alternative defensive arrangements were adopted for various production batches, but the pilot's single forward firing 7.9mm weapon, which could be used either fixed or free, was suplemented by either one 13mm MG 131 or two 7.9mm MG 81s fired by the bombardier through the transparent panels of the fuselage nose. Either one MG 131 or two MG 81s were provided to fire aft from the ventral gondola, and two MG 81s were fired aft from the rear cockpit canopy. From mid-1941, the aft section of the cockpit canopy was bulged to provide more space for manipulating the guns, and incorperated new circular armoured mountings for the twin MG 81s.'

Now as you know many have said that william green has made a mistake in this book and it has subsiquently been perpetuated by further books quoting his source. Often there are calls for a picture of a Ju88A-4 that would prove this claim. If you search this BB you will find many pictures of ju88s with various veiws of the nose gun.Some claim the only way the ju88 got the larger weapons mounted in the nose was at the expense of the bombsight (seen as a prodruding pod like structure on the lower front starboard side of the nose).

Well the good new is there are two pictures in this book with what i would say are two clearly different types of weapon in the pilots gun position!. There is the long barreled MG 81 and a short stubby barrelled gun which i can only assume is the MG 131 (or could it be a 20mm MGFF???, ok ok ill settle for 13mm!! )
I will scan in these pictures in the next few mins so you can compare them also.

Now im not sure but i feel its quite compelling evidence for this claim in his book that the KG crews changed the weapons to a heavier calibre after realising their defensive armament was proving less than effective. Something we AH ju88 pilots often claim also. For a LONg time we have tried to find some pictures that might help prove it  

However I will be adding something which is also in this book which points to the possibillity that we have a rather heavier bomb carrying capacity than the Ju88A-4 had which will come as a bit of a dissapointment to those same AH ju88 pilots.I'll add this later......

[hazed-]

ok i seem to have broken my scanner lol

I managed to do one scan and then i got bluescreened!

luckily although a very poor scan i did scan of the ju88a-4 with the stubby barreled gun in the pilots position so perhaps if someone could dig out a picture of the long barrelled gun you can see what i mean : if i could scan the other picture you would see the barrel is at least 2X the length of the one in this picture. Now this may not suggest 13mm necessarily, but it does at least point to the fact there were 2 different guns right? something to think about. Also you cant be sure but the angle of the gun does seem to appear as if its on a flexible mount ?

It would be great if someone else out there with this book and a BETTER!! scanner could scan in the pictures on page.454 top 2 pictures and this one on page.458

caption for pic says:
'(left) Ju88A-4s of III/LG 1 operating over the mediteranean in the summer of 1942.

Funked if you read this i cant believe all those times we discussed the guns in the ju88 and you often said you would only believe this gun was used when you see it, and you quote this very book so i assume you have it, and you havent noticed the difference between this picture and the ones preceeding it on the page i mention. It hit me as soon as i turned the page. Im looking now at the two pictures and by flicking the pages , you know like the cartoonists do, p454 & p458 and the difference is obvious!.

[hazed-]

the other thing i noticed which doesnt match our AH ju88 is the max loadout William Green mentions:

first about the A-1:
'Two internal bomb-bays were provided, these being capable of housing a maximum of 28 110lb SC 50 bombs, and two external carriers were fitted beneath each wing, inboard of the engines, these being capable of lifting a 1,102lb bomb but normally mounting 220lb bombs when maximum internal bomb load was being carried, providing an offensive bombload of 3,960lb.For short range missions under overload conditions, the external racks could carry four 551lb or two 1,102lb bombs, raising maximum load to 5,284lb'

this overstressed airframe was showing problems and there was even a ban on aerobatics due to possible structural failure which led to the development of the ju88A-4.

Ju88A-4:

'The forward bomb-bay was deleted, this space normally being occupied by a fuel tank, the bulk of the load being carried externally.This could comprise two 1,105lb bombs on the inboard ETC carriers, two 551lb bombs on each of the carriers immediately inboard of the engine nacelles,and two 551lb bombs on the outboardcarriers.The remaining internal bomb-bay could take 10 110lb bombs, a flare or incindary-bomb container.'

so it seems we may have too many 50kg bombs available in AH.Later he has the specs listed for ju88a-4 and heres what it says:

'Armament: (Offensive) Ten 110lb SC 50 bombs internally and four 551lb SC250 or two 1,105lb SC 500 bombs externally or four 1,105lb bombs externally.'

This means(according to this book) we should either have 10x50kg+2x500kg+2x250kg OR 4x500kg+10x50kg doesnt it?

why have no one mentioned this when clearly they own this book? this would also tie in closer with other books i have which put the A-4's max load at @5000lbs(some 4,408lb) than the present @6000 we have in AH. HTC not that im complaining because as an LW flyer the more ordinance is obviously better, but id rather have a loadout like the real thing if this is correct.Plus you guys did once accuse me of only posting stuff which favours increases in LW weapons which isnt true as you can see .

So which is right? @5000lb or @6000lb?

[Tony Williams]

Your scanned picture is not clear, but I would suspect that the short-barrelled gun is an MG-FF, the long-barrelled one an MG 151/20. These would have been fitted primarily for offensive, not defensive, purposes, e.g. attacks on shipping or ground targets.

I regard Green as a rather dangerous source when it comes to armament, because he put in a lot of convincing detail, some of which was wrong. For example, in at least one book he stated as a fact that later models of the Bf 109 could be fitted with an MK 103 engine gun, MK 103s in underwing pods and 15mm MG 151 on the cowling, thereby scoring 0/3.

Tony Williams: Military gun and ammunition website and discussion
forum

[hazed-]

Tony if you have the book try taking another look at the picture or even this one ive posted.
Notice that the angle of the barrel is not in line with the front of the aircraft((or its direction of travel) which suggests it is on a flexible mount.
Another thing is the MGFF has been shown on other pictures of the ju88 and it is mounted much lower where the bombsight is positioned (ie lower starboard side) (also shown in this configuration in 'conscise guide to Axis aircraft of WW2' david mondey which also lists 13mm as part of armament as do all other books ive seen the A-4 in so far,have you a reference which doesnt list 13mm?)

 So if like you said this is an mgff then did they really have 2 different places to mount them? why would they do this?

also consider the size of the mgff and take a look at the AH cockpit or a photo of the real cockpit and try to picture the mgff in the position of the 7.9mm we have in AH. It would be enourmous and far too unweildy for a pilot to use on a flexible mount, even fixed it would be hitting the navigtor in the back of the head .Of course im not aware of a 13mm shortbarrelled mg 131 either but it does seem rather strange that they would mount a 20mm at that angle in the photo. plus if this is where they mounted it, this blows the old arguement that the 20mm armed ju88 cannot have a bombsight because the mgff takes up the space where the bombsight is mounted.They cant have it both ways can they?
 
I think the 15mm cowl guns on the 109K series may well be a mistake but it is true that the 109K-4 had a modified engine housing which gave it a much bulkier appearance and I cannot see what the reason for this would be if not to house a larger cowl machine gun.
Has it been proven absolutely beyond doubt that the 15mm was never used on any 109K? or is this an opinion?
Ive often heard people saying there is no way it could have had it installed but ive yet to see anyone show just how they can be so sure.
If there never was 15mm installed in the K series could you explain the larger (higher) cowling? the engine wasnt taller so this cant be the reason.
as to the MK 103 engine mounted cannon , this i wasnt aware of, could you explain why this isnt possible or how you know this isnt true please?

anyhow this is a ju88 thread rather than a witch hunt for william green . the photo is a good peice of material , worth looking at closely. There are plenty of people out there with the book and a scanner and im sure they can scan in the pictures i  requested, (funked for one, as he often quoted it)

As for the ju88 it seems only common sense to me the ju88 crews would want a larger calibre weapon on the ju88 for defence.Most books quote that the A-4 was developed as a result of crews discovering defensive armament and protection was inadiquate and so it had armour protection increased as well as the defensive guns.
Do you also dispute the ventral gondola having either 13mm or 2xmg81s? im curious here what you think. After all look at the number of other LW bombers that utilised the 13mm for defence.why leave the ju88 out?

How are you so sure about this?

[hazed-]

tony i went looking for pictures of the various guns we are discussing to re-remind myself of their various sizes, as i assume this is the problem involved with their use as cowl mgs or indeed in my argument against the gun in the picture being a flex mounted mgff, I went to your website first of course , but found none there. Have i missed some pictures? could you point to them?

edit: I found the mention of the MK103 you refered to and it mentions there was trouble with the fitting of the larger barrel:

'The later production Bf 109 K-4s introduced an engine-mounted 30-mm MK103 cannon in place of the standard MK 108, but the 2.5-in diameter outer sheath enclosing the barrel of this weapon rendered a barrel change under operational conditions a somewhat onerous task.'

do you think he has made this up? a man who has spent and i quote the forward : 'more than 2 decades of painstaking research' to write this book. could you point me to where you found evidence that would make you think this is so? Its really got my interest now and i find this statement about the gun barrel a strange one to invent

[Fishu]

MG-FF/M to be precise..

[butch2k]

According to official docs :

A-Stand : MG81
B-Stand 2xMG81
C-Stand MG81Z
Zuzatzbewaffnung in Führerraum : 2x MG15
Zuzatzbewaffnung in der Kanzel : MG/FFM

[HoHun]

Hi Hazed,

>There is the long barreled MG 81 and a short stubby barrelled gun which i can only assume is the MG 131 (or could it be a 20mm MGFF???, ok ok ill settle for 13mm!! )

"Junkersflugzeuge 1933 - 1945" by Bukowski/Griehl quote original Junkers drawings showing a 20 mm MG FF/M with 2 drums of 60 rounds each mounted low in the starboard side of the transparent nose. It's obviously operated by the navigator and though not indicated, there can be no doubt it's a flexible gun. (This is also evident from the photographs of an A-5 and an A-4 armed with this gun in the same book).

From what I gather, the MG FF/M was fairly common as a flexible nose gun. It can be recognized by the large cylinder enclosing the base of the barrel, giving the gun a decidedly stubby look.

I can't make out anything on the photograph you posted, though :-)

The MG FF/M's muzzle should be about as far out as the forward ring of the sight, and the base of the barrel where it's protuding from the nose should be enclosed in a fat cylinder that's slightly tapering towards the muzzle.

I guess you might be able to recognize it in the original picture.

Regards,

Henning (HoHun)

[HoHun]

Hi Hazed,

>first about the A-1:

According to the same original drawings I already quoted, the maximum load capability per station of the A-1/A-5 was as follows:

Forward bomb bay: 18 x 50 kg
Rear bomb bay: 10 x 50 kg
Inboard wing root racks: port 1800 kg, starboard 1000 kg
Outboard wing root racks: 500 kg each
Optional outer wing racks: 250 kg each

For the A-4, it was:

Forward bomb bay: 18 x 50 kg
Rear bomb bay: 10 x 50 kg
Inboard wing root racks: 1800 kg each
Outboard wing root racks: 500 kg each
Optional outer wing racks: 500 kg each

Obviously, this means you could hang bombs under the Ju 88 until it collapsed on the ramp :-)

Lacking a detailed weight breakdown for the Ju 88A-4, I'd say it's total useful payload (fuel, oil, bombs) was about 4500 kg for a take-off weight of 13800 kg. The carrying capability for bombs was what was left over after deducing the necessary fuel mass from the gross payload.

So, 2 x 1800 kg would have been possible, leaving just 900 kg of fuel/oil. That would have been enough for about 2 hours of flight at full power, which would have yielded an entirely unsatisfactory combat radius. (In real life, that is :-)

Accordingly, operationally useful loads were usually much smaller than the possible maximum load. I don't think the optional wing racks saw much use for that reason - not only would the additional weight of the bombs cut down the amount of fuel that could be carried, but the additional drag would have further reduced the radius of action.

Rate of climb and ceiling were both affected as well, so bombing up a Ju 88 to the maximum would leave you with a very sluggish aircraft.

>'The forward bomb-bay was deleted, this space normally being occupied by a fuel tank

As the Junkers drawings shows, it wasn't deleted by default (like in the C-6 destroyer/night fighter which only retained the aft bomb bay). I don't think conversion was as easy as with the B-17 though, which could carry a droppable tank internally.

Regards,

Henning (HoHun)

[HoHun]

Hi Tony,

>Your scanned picture is not clear, but I would suspect that the short-barrelled gun is an MG-FF, the long-barrelled one an MG 151/20. These would have been fitted primarily for offensive, not defensive, purposes, e.g. attacks on shipping or ground targets.

Actually, heavy nose guns in a defensive role were called for by Luftwaffe doctrine. The reasoning was that engagement times would be so short an attacker wouldn't be deterred by light guns.

The drawbacks were short ammunition supply and a narrower cone of fire, but the former was accepted based on the short firing time to be expected in head-on attacks, and the latter based on the low probability of hitting (or getting hit) if the fighter came in at a lateral angle.

Regards,

Henning (HoHun)

[HoHun]

Hi Hazed,

>'conscise guide to Axis aircraft of WW2' david mondey which also lists 13mm as part of armament as do all other books ive seen the A-4 in so far,have you a reference which doesnt list 13mm?)

Junkers :-)

Actually, the MG131 wasn't introdue until 1943 I believe, so the A-4 series was well underway. The Battle of Britain had shown the need for a defense against head-on attacks (a finding later confirmed by B-17 crews), and the MG FF/M was the weapon available for that purpose.

If an MG131 was used in the Ju 88, it usually was in a "lentil" mount in the B position (upper rear). Originally, the Ju 88 was equipped with 2 lentil mounts on both sides of the aft canopy, but this could cary a bit. For example, the book I quoted shows an A-5 of KG51 with a single lentil mount plus 2 MG15 in beam positions of the canopy. In later Ju 88 modifications, the two lentils with one 7.92 mm MG81J each were replaced by a single one with a MG131. (The Junkers drawings list this with the C-6 only. As it had the drawback of a narrower field of fire compared to the twin lentils, it apparently wasn't considered fit for daylight operations. The Ju 188 also is equipped that way, but it had a top turret to provide 360° protection.)

There were many different lentil mounts, by the way, for 1 x MG15, 1 x MG81J, 1 x MG81Z (twin gun), or 1 x MG131. It seems the Ju 88 was never equipped with more than 1 x 13 mm or 2 x 7.92 mm in lentils though.

The C position could also be fitted with a MG131 replacing the MG81Z as in 1943, a mount was introduced that could take both weapons alternatively. The RLM data sheet notes "equipped with MG81Z" though, so it might not have seen use with the MG131 operationally.

>So if like you said this is an mgff then did they really have 2 different places to mount them? why would they do this?

The fixed one could be operated offensively by the pilot, the flexible one defensively by the navigator.

>also consider the size of the mgff and take a look at the AH cockpit or a photo of the real cockpit and try to picture the mgff in the position of the 7.9mm we have in AH.

Good visualization :-) But the MG FF was down in the nose, not up in the windscreen like the MG15.

Regards,

Henning (HoHun)

[Karnak]

All of the guns on our Ju88A-4 are the superior MG 81s.
http://www.hitechcreations.com/ahhelp/models/ju88a4.html
Now, I know we don't have the two guns for the pilot, nor a 20mm for him and we don't have the bombardier's gun options, but the rest of our Ju88's guns are the better of the options described in the opening post.

[Tony Williams]

Originally posted by hazed-
Tony if you have the book try taking another look at the picture or even this one ive posted.

Sorry, I misunderstood your initial post about the location of the gun - getting too lazy to read everything  I'm no expert on the Ju 88 and I'll go along with whatever Henning says!

I think the 15mm cowl guns on the 109K series may well be a mistake but it is true that the 109K-4 had a modified engine housing which gave it a much bulkier appearance and I cannot see what the reason for this would be if not to house a larger cowl machine gun.
Has it been proven absolutely beyond doubt that the 15mm was never used on any 109K? or is this an opinion?
Ive often heard people saying there is no way it could have had it installed but ive yet to see anyone show just how they can be so sure.
If there never was 15mm installed in the K series could you explain the larger (higher) cowling? the engine wasnt taller so this cant be the reason.
as to the MK 103 engine mounted cannon , this i wasnt aware of, could you explain why this isnt possible or how you know this isnt true please?
 

I have a number of sources but the simplest thing to do is quote Manfried Griehl's book on the Bf 109G/K (pub. Schiffer), which deals with planned as well as actual installations. Griehl is one of the few aviation historians to take armament seriously and I have never found an error about gun installations in his work.

The standard MK 103 action could not fit in the 109's cramped cockpit. As evidence for that, I can quote a 1946 document prepared by the Director of Aircraft Weapon Development of the RLM. A modified gun (MK 103M or 103 mot) was designed to fit, and there is one account of it being tested in a K-10, but it seems that it was unreliable. The K-8 was designed to use the 103M, perhaps before the results of the tests were known, but that was never built.

Griehl makes no mention of wing-mounted MK 103s for any 109; only MK 108s. That poor little plane would have had a hard time getting off the ground with MK 103s, they weighed more than twice as much as the MK 108s.

Griehl doesn't even mention the possibility of the MG 151 as a cowling gun in any Bf 109. I suspect that the higher cowling was to enclose the gun breeches of the MG 131; in the G series, there were big bulges in front of the cockpit to accommodate this.

Tony Williams: Military gun and ammunition website and Discussion forum

[HoHun]

Hi Tony,

>Griehl makes no mention of wing-mounted MK 103s for any 109; only MK 108s. That poor little plane would have had a hard time getting off the ground with MK 103s, they weighed more than twice as much as the MK 108s.

That poor little plane had a big big engine and could have carried the MK103s easily :-)

However, the Luftwaffe had much earlier decided that MK103s were no efficient anti-bomber guns, as the MK108 despite its low muzzle velocity was almost as accurate against bombers - big, non-manoeuvring targets - and even had a higher rate of fire.

Only the Fw 190A carried MK103 experimentally, but the MK108 became the standard anti-bomber weapon.

The Me 109K-8 was the same as a K-6 with a MK103 replacing the central MK108. The wing guns were internally carried MK108 (or MG151) in both cases (with the latter option probably responsible for confusing William Green).

The K-6 on the other hand replaced the K-4/R6 in Luftwaffe planning, having internally mounted wing cannon instead of the gondolas. "K-4/R6" was a bogus designation as officially, gondola weapons were designated "R4", but the Luftwaffe just carried over the Rüstsatz numer from the Gustav series.

I don't think there were any K-4/R6 conversions, and the end of the war prevented the K-6 from going into production (which was firmly scheduled).

Regards,

Henning (HoHun)