Here is made-up former, with a selection of balsa strips for the mast body.
...and then fill in the gaps with smaller strips.
This can be held totether with rubber bands while gluing, and then sanded to a rounded shape.
As an aside, if you are using Kinder Egg shapes, the rear radar dome is easily made out of two cut-down ends, joined with a cardboard cylinder. Here you can see the two blue halves, with one edge sanded away for a mounting bolt as shown on the fittings plan.
Here are the aerial supports going in. Make up shapes as shown on the plan. I put a couple of brass tubes through the mast to make sure the top supports were aligned properly.
Here I am experimenting with Gun shapes. You can see the several circular shapes obtained with a circle hole cutter, with one of them sanded to a cone. In the foreground are two conical shapes cut of household plastic bottles.
Glue 4 onto the formers as shown...
Here I am assembling the rear gun base, sanded out of solid wood.
The radar dish is simply made by gluing a bit of brass sheet to the cylindrical motor.
And here are several Kinder Egg shapes which can be obtained. Ideally, you want the ones which come in two distinct halves, without the little protuberances on the top.
Cut the Kinder Egg halves down by scribing a groove around where the cutting line is...
Now we can start on the mast. It is made on two formers joined together with balsa. I wanted a rotating radar dish, so made the formers out of brass with a soldered brass tube in the middle for the actuating rod.
