[johnpipe108]

I have been giving my M2 replica a severe and well-needed facelift, which includes new sidebars and recoil-adapter (the perforated cage on the rear) for the E-8 variable cradle adapter replica. The width of the recoil-adapter is determined by the sidebar spacing, which in turn is governed by the mounting dimensions of the E-10 adapter. It will be really helpful if anyone can supply the E-10 dimensions, especially the distance between the mounting faces, as my E-10 replica is only an approximation, and I would like to get the recoil-adapter width correct.

Current state:



BTW, the E-8 was the original Edgewater cradle introduced for the B-17C belly and waist guns; later in the war it was re-designed by simplifying and integrating the trunnions, and adding a second trigger forward of the left spade-grip. These changes resulted in a new Mil designation of E-12. In waist gun photos after July 1943, the presence or absence of a second trigger is usually the only way to identify whether E-8 or E-12.

Thank you very much in advance,

Regards, John

 

[johnpipe108]

I made inquiry at Smithsonian NASM, and obtained the following Technical Orders:

Technical Order No. 11-10-9, dated June 19, 1942. This covers, in general, the following: Adapter Assembly, Gun Mount, Types, E-5, E-5A, E-7, E-11, E-8, E-9, E-10, E-12 (.50 caliber M2 flexible aircraft adapters). This contains detailed description and explanation of operation and service. There is a full-scale, but un-dimensioned line drawing (Figure 7- Sectional View of Cartridge, Figure 8- Digram of Recoil Absorption Action), in addition to the following photographic illustrations: Figure 5- Type E-10 Adapter on Gun, Figure 6- Type E-8 Adapter, Figure 9- Bronze Slide Blockis of Type E-8 Adapter on Gun.

Also covers .30 caliber adapters C-12, C-13, C-16, C-17 and C-18.

T.O. 11-10-12, dated December 20, 1942, Revised July 20, 1943. Handbook Of Instructions With Parts Catalog, Type E-12 Gun Mount Adapter. This contains much useful info on E-10, and is a vital document for re-constructing an E-8 Adapter, also complete service manual for the E-10, with dimensional-drawings for the Inner and Outer Shell Assembly Bases, and the two special spanner wrenches.

Figure 13 - Ring-Spring Cartridge Dimensional Drawing. E-10 OAL 5-3/8" Normal, Major diameter at front swell 3.99"+/- .031, outer-shell minor diameter 3-1/4" +.031 -.000, mounting-boss face-to-face 3-5/8" +/- .010 (5/8-18 NF-3).

Regards, John

 

[dougstump]

John,

The “cage” at the rear of the E-8, 10, 12, etc. is not a recoil adapter. The gun does not touch that part of the adapter. It keeps the gunner away from the recoiling gun, allows the mounting of various sights, and mounts the grips & triggers. Depending on the adapter type, the “cage” was usually aluminum, either stamped sheet metal or cast.

I worked on the restoration of several of these when I was a volunteer with the 8[SUP]th[/SUP] Air Force Museum in the 80’s for the B-17 & B-24.

Doug