Madness? It's neat. Works well for some stuff. For airplanes you'd have to use a weldable alloy (which means one with less tensile strength, since alloys like 2024 aren't weldable) and it would have to be in a dead-soft condition for the explosion, then heat-treated to specified strength and hardness in a huge oven. Thin sheet would be more likely to tear, too, and thicker sheet would make a heavier airplane.
I use the term madness with utmost awe and respect in this case. It’s wild how well it works.
IIRC the lead ballon was a cube, the shape being critical to the filling process to prevent tears. The sheets were assembled flat on the ground in a very specific way then opened like origami as they filled it.
You are correct. Myth Busters built a square, cubic lead balloon.
I'm really not sure why people are soured about this. The technique obviously works for the boat hauls. Seems to have worked very well. The difference I can see being and this might be made up with a smaller charge of explosive, is the lightweight needed for aircraft and the material is not being as durable as what you would install on a boat frame. The other is if this would work with a smaller amount of explosive, a much smaller amount of explosive in a controlled environment with the money be compatible to other forms of manufacturing.? As much as gets bad at around on forums for aircraft this really doesn't seem like such an extreme possibility. The tried and true methods obviously work and that is what I would stick with but on a commercial scale of light aircraft in a much controlled environment this could become a part of the manufacturing process maybe.Can you find me a nice step by step?
Explosion formed wing ribs sound way better than press stamped wing ribs
You're still stuck with welding the sheets together, then in dealing with sheet thinning as it stretches, in areas that might not be convenient for structural strength. And subsequent heat-treating to regain the strength. Boats can afford to use thicker sheets of soft, weldable aluminum that doesn't need further heat-treating; they likely weld in internal frames to stiffen the structure. It won't be a lightweight monocoque hull, but it might still be lighter than a lot of fiberglass boats.
You realise, you just did exactly that?
It is more a question how exactly things are built and how high the mass penalty ist. FRP can be designed extremely light. On most aircraft not strength but buckling / stiffness is the main driver of mass with FRP, and, of course, process steps necessary. And if you don't have high penalties for structural mass (to a certain degree), you can allow for "some more"
I'm no authority on structure weights, but did you notice the Cirrus interior 'appointments'? I'd bet on 50 lbs extra just inside the cockpit. The angle valve 360 is at least 30 lbs heavier than the parallel valve version. There's also the fact that it's a cantelever wing instead of strut braced.
Have you seen how the Questair Venture fuselage (compound curved aluminum) was formed? According to magazine articles back in the previous century, it was stretch formed by dropping a giant chunk of concrete in the shape of a male mold into the female mold. THUNK. Fuselage half...
