Flexible gun mount question..

[Cvairwerks]

I was reading through some of the materials that I have on the AT-21 while waiting on some computer stuff to finish. In looking at the weapons stuff, it describes the nose gun mount as a K2A ball mount. After several hours of net searches, I cannot find anything on the K2A. I've posed the question on the G503 board and a website devoted to the M2 machine gun.
So far no responses in either location.

Anyone have any idea where I can find anything on the mount? I've got all of the prints for the a/c on microfilm, but don't have an IPB to get p/n's from, so I would have to look at all 14,000+ drawings to see if there is anything on the film. After going though hundreds of pages of drawings and thousands of pages of manuals every week at work, it doesn't take long to make me punch-drunk running the film on the viewer.

Ideas, pointers, sources...any or all would be most appreciated.

[DryMartini]

Thinking off the top of my head, CV -

The ball mount may be Government Furnished equipment,
and therefore would not be in the microfilm. I know I have
a similar problem with the B-17.

[Cvairwerks]

Yeah Bill, it was probably GFE, but they still would have had to have some data on it. I deal with GFE all the time at work and while we may not have all the drawings for that equipment, we do have enough that we can engineer the installation of it. The big mystery is trying to find anything on this mount. I can't even find a picture of one, or a description of it, at all.

In my research, I did find out that the turret was removed while the a/c was assigned to Ellington as a field hack. Apparently, it suffered a hard landing or two or three... and they fractured a longeron supporting the turret mount. As the a/c was not going to be used in it's designed role, they removed the turret itself and faired over the hole. I found someone that worked on her there at Ellington too. I need to see if she is still alive and can fill me in a little a bit while the a/c was flying down there.

[Taigh Ramey]

As you already know the K-2A is a ball socket mount for the .30 cal ANM2 flex gun. This is the same mount used in all sorts of WWII aircraft including the early B-25's & B-17's, B-34's etc. Here is some information that might be helpful to you.



I would think that the aircraft manufacturer's drawings might have outline and assembly drawings but likely will not have the production drawings for the mount as it was GFE. There is a chance I might have the prints on a set of microfilm I have but it will be spendy to get them scanned. I would ask Jay Wisler as I bet he might have one for sale or know where to get one. Carl Scholl may have one too.

Here is one in our collection:



It still has layers of Plexiglas between the mounting flanges.

The K-2 didn't have the spring loaded cap to keep the wind out like the K-2A. There were usually several of these mounts used with one gun that would be slipped into the socket in the direction of the attacking aircraft. In the early B-25 the gun was stowed on the right side of the nose and there was a K-2A mounted in the nose and left side of the bombardier's compartment. These sockets would mount directly in the plex sometimes without any additional support.

Here is a photo of a field mod where they put 6 50's through the glass nose. You can see where the K-2A socket was mounted originally in the nose and the left side and has since been blanked off.



The K-2 and K-2A were cast and the K-3 was stamped. The K-4 was similar but for the ANM2 50 cal gun.

I hope this is helpful,

Taigh

[Taigh Ramey]

Here is a cool old magazine cover shot of a B-17E showing the gun mounted in the lower socket and the other available sockets. Imagine having to pull the gun out and get it into another socket in the heat of battle. 30 below zero and your sweating like mad I have been told!



These are the K-2 mounts without the spring loaded cap to keep the wind out. Probably darn nice to have that wind cooling you off at low level in the south Pacific but not so nice at 20,000 feet...unless you are sweating!

[b29flteng]

How did they keep the recoil from shattering the plexiglass?

[Taigh Ramey]

Surprisingly the 30 cal recoil was not strong enough to damage the plexiglas and didn't seem to need additional support. These gun mounts were typically hard mounts without any recoil absorption.

The 30 cal was quickly replaced with the 50 throughout Army and Navy aircraft which did require additional support and gun mount adapters that could absorb the energy during recoil. You can see the difference in the early to late B-25's with the change of the 30 cal to 50 cal in the nose. You also see that the idea of moving the gun from one socket to the next was also dropped fairly early in the war. Incidentally the 50 was also moved from socket to socket in early B-24's too.

[Cvairwerks]

Score a big one for Taigh.... Thanks a bundle, as that's the first info that I've ever seen on the mount. I've pawed through Jay's website off and on for years and have never seen one listed there. Doesn't mean that he won't have one. I will send both Carl and Jay queries as to whether they have one. Just for reference Taigh, what manual is that page in? If other sources don't pan out, I just may pop out there some weekend and oogle yours and make a set of drawings at the same time.

[gemmer]

Surprisingly the 30 cal recoil was not strong enough to damage the plexiglas and didn't seem to need additional support. These gun mounts were typically hard mounts without any recoil absorption.

The 30 cal was quickly replaced with the 50 throughout Army and Navy aircraft which did require additional support and gun mount adapters that could absorb the energy during recoil. You can see the difference in the early to late B-25's with the change of the 30 cal to 50 cal in the nose. You also see that the idea of moving the gun from one socket to the next was also dropped fairly early in the war. Incidentally the 50 was also moved from socket to socket in early B-24's too.

I must respectfully disagree about the B-24 nose guns. The first model to have .50 cal nose armament was the C model( 9 production aircraft). Those and the earliest D models had a single gun mounted high in the apex of the nose. There were no other gun ports. Soon after, the gun was relocated to the extreme lower portion of the nose and the upper port was deleted.
Starting in stateside modification centers, two additional cheek guns were added that required the relocation of the pitot tubes, and an additonal sighting window on the port side. These changes were incorporated into the production lines over an extended period of time.

Moveable nose gun locations were limited to .30 cal guns in B-17s, B-25s, and a few B-26s.

Duane

[gemmer]

[

[Taigh Ramey]

I must respectfully disagree about the B-24 nose guns. The first model to have .50 cal nose armament was the C model( 9 production aircraft). Those and the earliest D models had a single gun mounted high in the apex of the nose. There were no other gun ports. Soon after, the gun was relocated to the extreme lower portion of the nose and the upper port was deleted.
Starting in stateside modification centers, two additional cheek guns were added that required the relocation of the pitot tubes, and an additonal sighting window on the port side. These changes were incorporated into the production lines over an extended period of time.

Moveable nose gun locations were limited to .30 cal guns in B-17s, B-25s, and a few B-26s.

Duane

I agree with you Duane. I had a picture in my mind with empty sockets in the nose of the early B-24's and when I went back to check I found just what you wrote about. Sorry about that and thanks for the correction!

Taigh