“Little Boy” and “Fat Man”

The two atomic bombs dropped on Japan to close World War Two have been steeped in controversy ever since.


Fat Man on the left. Little Boy, on cart, at right.

The bombs were the product of the “Manhattan Project” that started in 1942 under Major General Leslie Groves.  This was a joint project with Britain and Canada and was a further development of the British “Tube Alloys” program.  By most counts it was the third most expensive weapons system of the war, after the German V2 and American B-29. Given that the bombs were dependent on the B-29 as a delivery system this is a massive national effort.


The seeming unending “controversy” is perhaps understandable since these are, by far, the most destructive weapons ever deployed and the only atomic weapons ever used.  But I don’t think study of the time and events needs to go too deep to realize there was never a reasonable expectation they wouldn’t be used. The initial impetus for the weapons was a desire to develop them before Germany could.  But by early 1945 it was clear there was no need to use them against Germany due to a rapidly approaching defeat.
Japan however, was fighting with increasing fanaticism and desperation.  Employing suicide pilots against ships and continuing resistance past the point of no hope it was obvious a final victory would be very costly in lives.  Our signals intelligence and code breaking of the period was also extremely good; we knew in mid-1945 that there were Japanese leaders ready to sue for peace, but they were not a majority and were not making policy. (I highly recommend “Marching Orders” by Bruce Lee for a thorough look at American signals intelligence in the war, especially in the closing events).
Japan was under a complete naval and air blockade and her cities were being burned to the ground. Japanese territory was falling rapidly to allied assault.  Japanese leadership was seriously discussing their national destruction as if it was the “honorable” course of action.
American leadership was ready to accommodate them, while hoping for a less cataclysmic solution.  Enter the bomb.  At the time, most people with knowledge of the project regarded the bombs simply as really big bombs.  Understanding of radiation, fall out, and the world changing aspects of nuclear weapons were pretty limited.  We had a new weapon, and an enemy who needed a reality check; NOT using them would have been pretty unthinkable. Not to mention a betrayal of trust for the hundreds of thousands of Soldiers and Marines getting ready to invade the islands.
No doubt, in the aftermath, many have regretted ever letting that particular genie out of the bottle.  But faced with the cost of an invasion it seems likely the bombing DID save lives, both American and Japanese.


Just a little scale perspective. Fat Man was a large piece of ordnance. Not as big as a British “Grand Slam”, but big enough the B-29 was the only American bomber for the job.  Maybe some day I’ll have a B-29 to pose with it…

I do need to mention that was another element in the final Japanese decision to surrender.  The Soviet declaration of war was nearly as big a shock to Japanese leaders as the bombing. Many had apparently clung to a *unrealistic* hope that the Soviets would help negotiate some sort of compromise peace.  Those hopes were discredited concurrent with the atomic bombings.  So facing ruin and no options changed the balance of power within the Japanese government.  At least enough to say surrender vs fight to utter annihilation became a total toss up. Hirohito himself cast a tie breaking vote to end the war.


Little Boy is obviously much less massive.

The two bombs used represent very different technologies.  Little Boy was a Uranium bomb. It used a rifle type detonator that slammed one mass of Uranium 235 into another.  This was considered a simple type of weapon that wasn’t even tested prior to use. But Uranium 235 is very difficult to process and that really became a prohibitive factor in building any more such bombs.
Fat Man was a plutonium bomb. It was triggered by firing multiple masses of Plutonium into a central core.  This detonator was considerably more complicated to produce and was the reason for the world’s first atomic test at Alamogordo NM.
Much is often made of saying the Nagasaki bombing exhausted the American supply of atomic bombs. This is only partly true.  There were elements for a third bomb being prepared for transport to Tinian when Japan surrendered, and series production of Fat Man type bombs was on the immediate horizon.

The bombs shown here are from the vintage Monogram B-29 Superfortress kit.  They are extremely easy to assemble little items, greatly complicated by poor molding and fit issues.  I spent far more time filling and sanding, filling and sanding, and filling and sanding again than I did with “assembly”!  And in the end, its still obvious I’m no “master builder”.

I have mentioned before that I am getting started with a basement remodel project at home that will shut down my modeling entirely for a few months. I’m not sure if I might get something else done before that break; I hope so, but don’t bet on it!

~ Dave

About atcDave

I'm 5o-something years old and live in Ypsilanti, Michigan. I'm happily married to Jodie. I was an air traffic controller for 33 years and recently retired; grew up in the Chicago area, and am still a fanatic for pizza and the Chicago Bears. My main interest is military history, and my related hobbies include scale model building and strategy games.
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10 Responses to “Little Boy” and “Fat Man”

  1. Theresa says:

    The death of Japanese was regrettable but invasion was unthinkable in cost. The island hoping showed the fanaticism of the Japanese will. The last 3 month of the war was the most costly in terms of material and manpower. The planers were looking at deaths of 1.5 to 6 million. Plus the Red Army would have to be deployed and that would end up with a divided Japan as much as Germany and Korea. That was unacceptable so the decision to drop was to prevent a divided Japan and many war atrocities caused by the Red Army prevented.

    • atcDave says:

      All good points. I think the Kamikaze, Iwo Jima and Okinawa were huge factors. I avoided mentioning specific numbers on casualty estimates because they are so conjectural. But the bombings clearly saved American lives, and likely saved Japanese lives as well.

  2. Pierre Lagacé says:

    Still have those two bombs in my stash Dave.
    Didn’t build the Enola Gay.
    I show post something about my build someday.

  3. Pierre Lagacé says:

    So much controversy around the dropping of the Bomb.

  4. Pingback: Boeing B-29 Superfortress | Plane Dave

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