Description
U.S. Air Force Emerson Model B-4 Auxiliary Ammunition Booster for B-47B Stratojet, P/N 535372-1
Item Overview
This original Emerson Electric Model B-4 auxiliary ammunition booster was used with the twin-.50-caliber tail-turret system installed on the Boeing B-47B Stratojet. The electrically powered booster pulled linked .50-caliber ammunition through the aircraft’s feed chute toward the tail guns. Its anti-rollback mechanism prevented the ammunition belt from moving backward when the guns stopped firing. The booster is stored in its military preservation container. The crate identifies the assembly as Model B-4, part number 535372-1, under U.S. Air Force contract AF 33(038)-14775. A faint marking indicates that the unit was packed, preserved, or reprocessed in 1953.
Identification and Features
- Item type: Auxiliary ammunition booster assembly
- Manufacturer: Emerson Electric
- Model: B-4
- Part number: 535372-1
- Aircraft application: Boeing B-47B Stratojet
- Parent system: B-4 tail-turret and fire-control system
- Armament supported: Two .50-caliber machine guns
- Operation: Electrically powered
- Purpose: Pulled linked ammunition through the feed chute toward the guns
- Mechanical feature: Anti-rollback mechanism
- Contract: AF 33(038)-14775
- Preservation or packaging date: 1953
- Status: Inert mechanical and electrical aircraft equipment
How It Worked
Aircraft ammunition often had to travel through long or curved feed chutes before reaching the guns. Pulling the belt through this route placed extra strain on the gun-feed mechanisms.
The auxiliary booster provided powered assistance by drawing the linked ammunition through the chute and toward the tail guns. This helped maintain a steady ammunition supply during firing.
When firing stopped, the booster’s anti-rollback mechanism kept the ammunition belt from sliding backward. This helped preserve the belt’s position and reduced the chance of a feed problem when firing resumed.
This assembly supported the ammunition-feed system. It was not one of the machine guns, the radar sight, or the main B-4 control panel.
Contract and Date Markings
A surviving Emerson B-4 turret control panel manufactured under the same Air Force contract is marked “PANEL ASSY–CONTROL B4 TUR.SS”. That panel has separate ammunition counters for the left- and right-hand guns and carries an M.F.P. date of June 13, 1953. The matching contract and system markings support this booster’s connection with the B-4 twin-gun installation.
An AF51 serial-number prefix appears consistent with a fiscal-year 1951 procurement series. However, it should not be treated as a confirmed manufacturing date. The visible 1953 marking is best described as a packing, preservation, or reprocessing date.
Historical Background
The Boeing B-47 Stratojet was a six-engine, swept-wing jet bomber developed during the early Cold War. Its speed, high-altitude performance, and modern shape influenced many later jet aircraft.
The B-47B became the first major operational version used by Strategic Air Command. Modified B-47B aircraft received a two-gun tail turret equipped with .50-caliber machine guns and the B-4 fire-control system. The guns were operated remotely, allowing the crew to defend the aircraft without placing a gunner inside the tail.
The B-4 system combined aiming, control, ammunition monitoring, and gun-support equipment. The auxiliary ammunition booster was part of the hardware that kept linked ammunition moving toward the guns during operation.
Later B-47E aircraft used two 20mm cannons and an improved A-5 fire-control system. This makes the Model B-4 booster a part associated with the earlier B-47B twin-.50-caliber installation rather than the later B-47E armament system.
Condition
This is original U.S. Air Force military surplus in a long-term storage container. The booster and container may show aged preservative, finish wear, scratches, discoloration, surface oxidation, dust, stains, fading, and other signs of storage.
Crate markings may be faint, incomplete, or difficult to read. The assembly has not been tested, and its electrical or mechanical operation is not guaranteed. It is offered as a collectible, display, restoration, or research component.
This listing is for one Model B-4 auxiliary ammunition booster assembly in its storage container. The B-47 aircraft, machine guns, linked ammunition, feed chutes, turret, radar equipment, control panel, wiring, and other components are not included unless specifically pictured or stated.
Ideal For
- Boeing B-47B Stratojet restoration research
- Strategic Air Command collections
- Early Cold War aviation displays
- Aircraft armament-system collections
- Emerson Electric military-equipment collections
- U.S. Air Force surplus displays
- Aviation museums and educational exhibits
Approx length 9", Approx width 8", Approx height 8", Approx weight 7.0 lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item’s general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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