Photo Gallery

77-BT-34Photograph of personnel checking a casing.

A significant number of extra casings were shipped to Tinian Island and used in various tests with “dummy” bombs which contained all the active components of a working atomic bomb, but no fissile material to test out and prove the assembly procedures for the actual devices themselves.

Fat_Man_Assembly_Tinian_1945Implosion Sphere for Fat Man nearly assembled and about to be placed inside it’s casing.
Photograph from LANL History website showing partiallyshrouded Little Boy unit designated L-1.

This unit was assembled with non-nuclear components and dropped on 23 July 1945. Test was a complete success.

77-BT-173Little Boy unit checked up to a bank of equipment; possibly to test/charge components within the device.

Unknown whether this is a test unit or L-11; the unit dropped on Hiroshima.

77-BT-172Project A (Alberta) member Comander A. Francis Birch (left) numbers Little Boy Unit L-11 while Norman Ramsey (right) watches.

This is the actual unit which was dropped on Nagasaki.

Final Bomb Assembly

Fat Man devices after they were assembled, underwent a final procedure outside the Assembly Building, where their crevices were filled with putty, and then over-sprayed with sealant to maintain the proper environment within the device during the time it would take to deliver it to the target.

77-BT-183In this photograph, you can see the putty being applied to the forward polar plate.
 77-BT-185The sealant is now being applied via spray gun.
77-BT-186Workers have substantially completed application of the sealant.

Note the writing on the tail fin assembly and the logo on the bomb’s polar plate and on the worker’s coveralls.

 FatMan954c10This is a frame taken from a color movie taken of the sealant application, showing the color of the device and sealant/putty.
 77-BT-177Once the device was virtually complete, workers began to sign their names and various exhortations onto the device.

77-BT-182Close up of names on tail assembly of Fat Man.

77-BT-181“A Second Kiss for Hirohito!” signed by Rear Admiral W.R. Purnell, USN on the side of Fat Man.
77-BT-187The completed Fat Man device is being lowered/checked over on it’s transport dolly for the trip to the airfield.

Bomb Loading

"Fat Boy" on the way to the loading dock.

“Fat Boy” on the way to the loading dock.

At the loading dock.

At the loading dock.

Maneuvering "Fat Boy" into position.

Maneuvering “Fat Boy” into position.


In position and ready to be loaded into the Bomb Bay.

In position and ready to be loaded into the Bomb Bay.

77-BT-12177-BT-122Elanor Gay being positioned over the loading bay.





The Bomb Pit today.

The Bomb Pit today.







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