Fat Man and Little Boy

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lakeroadster

When in doubt... build hell-for-stout!
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I know they were designed to fall, and not be launched, but anybody ever seen or built a model rocket of Fat Man or Little Boy?

What's the thought on the aerodynamics of doing so?

Seems like a good fit for folks that like scale models of vintage warfare rockets and the like.

Little_Boy+Fat_Man.jpeg
 
There was a guy in Australia who built one and actually sold it as a kit. I was interested but it was a bit pricey.
 
Krusty made a flying bomb. I think it used the little engines (13mm), not the "normal" ones (18mm). I seem to remember it was based on one of those chocolate-covered plastic eggs that are banned in the US (we're too stupid to know which parts not to eat).

[edit] Took some digging, but found it:

https://www.oflittleinterest.com/in.../27-rocketry/188-kindersupriseeggbuildfeb2012

[edit 2] of course, I'm wrong. It *did* use 18mm engines...
 
FWIW - this movie was pretty good.


https://en.wikipedia.org/wiki/Fat_Man_and_Little_Boy


Fat Man and Little Boy (a.k.a. Shadow Makers in the UK) is a 1989 film that reenacts the Manhattan Project, the secret Allied endeavor to develop the first nuclear weapons during World War II. The film is named after the weapons "Little Boy" and "Fat Man" that were detonated over Hiroshima and Nagasaki, respectively.

fat_man_little_boy_original_film_art_spo_2000x.jpg
 
Yes, there was a guy in Illinois who did Little Boy. I did some Rocksim design stuff for him to do Fat Man. If I think of it I will post the files for you to check out.


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There is currently a movie on Amazon Video called "the Bomb" iirc, its an excellent documentary of the Manhattan Project.
 
2022-02-19 Update:

I'm back on the Fat Man model rocket design.​
In spring of 2021 @PSLimo succesfully launched his 38mm Fat Man... here's a link.​

The California Parachute

The Fat Man was designed with a tail section that was referred to as "The California Parachute" (see Mike Wagnon's exlpoded view below). Basically an 8 fin boxed aluminum assembly with an inverted transition that funneled air, much like a parachute.​
1988-Chuck-Hansen-Fat-Man.jpg
@PSLimo didn't use this drag inducing feature on his rocket, I want to take a look at building the rocket so these "California Parachute" baffle plates can be easily added / removed to see how it affects stability. My mindsim reasons that I can eliminate a lot of the nose weight and still end up with a stable rocket (think of a spool rocket). Not that the apogee will be any higher with the baffles, it'll just be a lighter weight rocket. I should be able to test this during the swing test. Add baffles and remove nose weight, rinse and repeat.​

Open Rocket & The Fat Man

I created a full 1:1 scale Open Rocket model based on dimensional data I could find online related to the original Fat Man design. Then I scaled that down for a 29mm motor design. The upper and lower ellipsoid "egg" shape I'm thinking can be turned on my wood lathe. The box fin section made from plywood basswood.​
The Open Rocket Sim needs 15 ounces of weight just to minimally stabilize a 15 ounce rocket (w/o 29mm motor). That's why I'm hoping to drop some nose weight by swing testing using the California Parachute baffle plates. As is.. Fat Man is pig.​
2022-02-19 Fat Man 29mm Open Rocket Simulation.jpg
But, if I use the base drag hack discussed in the Apogee Peak of Flight Newsletter 154 I can remove all the nose weight and the rocket is still stable​
1645311698745.png


319y8epqru721.png Fat Man Boxed Fin Arrangement.jpg 2022-02-19 Fat Man 29mm Open Rocket Photo Studio.jpg
 
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