Quote:
Originally Posted by cdavenport
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I can tell you from looking at its structure that it was designed to retard the fall of the bomb by creating drag. Modern nuclear weapons employ a parachute drag system to
allow the bomber to escape the worst of the blast effects.
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About the function of the tail structure, I found a reference when they talk about the difficulties to stabilize in a correct and predictable way the bomb when it falls.
Little Boy, with its simple and conventional shape, didn't give any relevant problem regarding its stability, but Fat Man with his fat shape had a tendence to roll, doing unpredictable its trajectory. The shape evolved giving a more aerodynamic profile to the body, doing it to seem to an egg, and enlarging and adding a sort of hopper to the tail.
The data from Wikipedia are
Fat Man
Weight 10,213 pounds (4,633 kg)
Length 10.7 feet (3.3 m)
Diameter 5 feet (1.5 m)
Little Boy
Weight 9,700 pounds (4,400 kg)[1]
Length 120 inches (3.0 m)[1]
Diameter 28 inches (710 mm)[1]
If we compare the data, we can see that the lenght and the mass for both the weapons are similar. What is different is the diameter, almost double in Fat Man than in Little Boy.
So, regarding the speed, bigger frontal section = bigger resistance = less velocity and more time for the bomber to go away.
Rather, for the stability issue, we had to increase the resistance of the tail, like we do with the feathers on the tail of an arrow and so making slimmer the Man.
I don't know if my interpretation is correct, but comparing the two bombs, it seems logical, in my mind.
I can't wait to see your model.
Best, Nando