Early B-17 Armaments & related topics - a few tidbits

[johnpipe108]

Hello, I'm a newcomer here, but got interested in early B-17 armaments by a strange route - two Hollywood movies, Destination Tokyo (uses replica E-8 mounted M-2's & Boeing B-17 side-gun ammo boxes in a submarine movie!) and Air Force, both by Warners. I've been corresponding with NASM archives for about a year and a half or so, and have collected a number of armament diagrams and T.O. covers, and some interesting orders. Odd to be bitten by the early B-17 bug at all, as my main military interest for most of my life (born December 1944) has been the WWII Fleet Submarine!

I had started an essay on this topic last year, but it needs a complete re-write as of a response from NASM dated 21 March 2013, which clarifies a great deal of the previously acquired info, as I had made a number of deductive errors (I'll bet that's not unusual in the B-17 area!).

An item of interest, partially quoted here: The "R" & "U" order, T.O. 1-1-81, January 27, 1943. General -- Reclassification of Airplanes. Section 2. Airplanes Affected. (2)a. Combat Airplanes - "The following combat airplanes, no longer considered entirely suitable to perform their primary combat missions, will have their standard model symbols prefixed by the letter "R" (Restricted), as noted:"

The list begins with RA-17, includes RB-17, RB-17B, RB-17C, RB-17D, and also such well known warbirds as RB-24, RB-24A, B, C, RB-25, A, B, RB-26 ... through the RB-37; fighters from RP-12E through RP47C, there are 57 aircraft restricted en bloc! Also reclassified were 23 Cargo Airplanes in part b, reclassified "U" (Utility), from UC-35 through UC-94.

"3. Any of those airplanes listed in paragraphs 2.a. and 2.b. which have previously been placed in the obsolete class (Z prefix) will retain that classification and not revert to a Restricted or Utility classification.

By Command of Lieutenant General ARNOLD: WALTER H. FRANK, Major General, U.S.A., Commanding General, Air Service Command."

Armaments: The Air Force film shows E-8 (replicas, like all the sim-fire .50's seen) on the B-17 side guns (and others, some "Hollywood Artistic License" perhaps here); T.O. 01-20-E-72 of 19 July 1942 ordered the replacement of the Type E-4 gun mount adaptors with Type E-12 adaptors on B-17B, C, and D aircraft. I have wondered where Hollywood got the E-8 copies from, or whether this order might have been filled (partially, perhaps) with E-8 mounts on the aircraft in question, or else perhaps Hollywood had been shown the E-8 drawing, or the photos from T.O. 11.10-9 (the only documentation I have seen on the E-8 adaptor). Can't help but be curious on such questions!

I've also been wondering why the B-17E & F used E-8 (single-trigger) instead of E-12 (dual-trigger) adaptors.

I've seen, on the web, a color photo of a pre-upgrade B-17B turret-mount (interior view with gunner), but the E-4 adapter is missing from the photo! That missing E-4 had originally had me confused and could not visualize such on the B-17C of course. There are "gotchas" in some of those "historic" but posed photos!

The AAF ordered that the streamlined side turret on the B-17B be removed and replaced by a flush installation, per T.O 01-20EB-17 (7 Aug 1940) although this is is not reflected in the illustrations in 01-20EB-2 (Handbook of Service Instructions ...").

We have been trying to determine the earliest date for upgrade of B-17 aircraft to 500 round side-gun boxes; it looks like possibly early 1943, perhaps around April/May, and not later than September 15 (revision date for B-17F armament diagram 65-6806, P. 421 of T.O. 01-20EF-2 issued originally apparently December 1, 1942 and "Corrected to December 15, 1943). The B-17F armament diagram mentioned shows that the side-gun and top-gun Boeing 100 round boxes were retained for backup.

I have obtained photocopies of 4 Boeing ammo-box drawings; the top-gun box (B-17C/D & F) 15-6999, the side-gun box (B-17C through F) 15-7469, the B-17C/D bottom-gun box 15-7453, and the 500 round top-gun box 14-3286 for the B-17F. The side-gun box, as seen in many side-gunner photos, originally had re-inforcing embossing on the bottom and rear; it was deleted by rev I,J (re-draw), probably when it was no longer a primary ammo-feed. I am not certain, but I believe the C-2 mount-adaptor was used on the feed-side pawl-bracket of the M-2's to hang the boxes prior to the Hughes flex-bracket.

I have also recently acquired an AAF Type 0-1 33 round box with original cardboard packing box, un-issued condition with minor corrosion on the spot welds, and can say that the Boeing 100 round top-gun box was a virtual expanded clone of same. The mounting clip is the exact same pattern as on the Boeing side-gun box. The O-1 was steel, but the Boeing top, bottom and side referred to were Aluminum alloy. All have either the same or approximately the same mounting clip, plus buttons on the top and bottom boxes to secure the boxes via a clip on the underside of the E-5a dual-adaptors.

We are still looking for sources of AAF drawings for the flexible gunnery adaptors, as NASM archives does not have a complete AAF collection.

I wanted to get some of this out there now, just in case! My health has improved from Stage 3 terminal; I still have technically a terminal illness, but it's now probably a few years rather than months before I'm down for the count!

With warm regards,


John Meshkoff

[DryMartini]

John,

You have information that I've been dying to get for our B-17 project.
I'll get in contact with you.

-Bill

[johnpipe108]

I have just been working on a drawing for the E-10 Ring-Spring adapter cartridge, used on B-17 and other aircraft armaments. This is the working part, the recoil adapter, with dimensions as taken from Handbook of Instructions With Parts Catalog, Type E-12 Gun Mount Adapter, T.O. No. 11-10-12, revised July 20, 1943.



It's been some time since I tried getting a plot and converting it, and the lines came out somewhat faint. I will experiment when I make time and try to get a better line quality in the finished display file. Some dimensions are not given, so I've estimated those and as you see they are commented. I've only given those details needed to make a display replica for restoration (the complete dimensions for the bona fide are not in the manual).

Regards, John

[johnpipe108]

I have collected a few pertinent related images. First, the gunnery-manual page for the E-12 adapter, used on B-17B, C & D aircraft after the upgrade from the E-4, also I believe used on the B-24 side-guns:



The E-8 flexible adapter, as used on the B-17E & B-17F sideguns; note the distinct trunnions, single-trigger, and unusual trigger-pull limit-adjuster, a ring in the right spade-grip that was mounted off-center.





The E-10 ring-spring recoil-absorber unit, as mounted:




Air sergeant at Harlingen Air Gunnery School, holding twin .50 caliber M-2's mounted on E-8 adapters; I cropped this image from a montage in the HAGS journal, where it was printed reversed left to right to better suit the montage, and corrected here. Note the C-2 adapter bracket, used to hang individual ammo-boxes, mounted on the feed-side pawl bracket of the M-2. Thanks to the liberatorcrew CD by Jon Moran.



E-10 unit, showing the correct application of twisted brass wire to secure the mounting bolts against loostening from the recoil:




Hope this is helpful,

Regards, John

[DryMartini]

]
Excellent information, John!

Caught your Ma-Duce thread. Pretty cool!
http://www.scale-models.co.uk/other-mod ... 1-8-a.html