A few behind the scenes pics for anyone interested. Captions to explain are under each picture.
Aluminum work hardens too much to be able to push these shapes very far without applying heat to soften and normalize the metal. This has to be done in many steps. Metal is 3003 H14 aluminum in .063 thickness for the boosters, and .050 for the cowl.
While the metal is still hot, I work it with a teardrop mallet into the metal die I have . I do this for the upper and lower cowl pieces individually. The parts are trimmed later on.
The flanges are fairly easy to do with a little heat and hammering. Without the hammerform die underneath, I would not be able to make these parts accurately.
What the upper cowl looks like fresh out of the hammerform die.
Lower cowl section
This is the sheet metal for one of the boosters going into an old school pinch roller. This requires several passes to get it to curl into a tight enough cylinder.
After carefully measuring the diameter (7.25") The boosters are held in place with Cleco clips, and then riveted every 1/2", 1/4" from the edges.
This is a homemade flange tool. I use it to bend the edges of the bottom of the booster over 90 degrees to make a flange. This takes three passes to get it to roll over fully.
After some hammer and dolly work to flatten the flanges, I take a file to the surface to make it nice and flat. You can see the difference between one with a flange and one without in this pic.