I've been working on the Pneumatic Giraffe model today. The main part is the telescoping neck. I've decided to use four sections, that said, the model could be easily modified to include more. Notice though that the wider sections get progressively shorter so there is a natural limit. Anyway – I've gone with four.
The sections of neck fit inside the other. To stop them coming right out I've glued a small double thickness card rectangle on both sides of each piece. The narrower tube has this lip on the outside, the wider piece on the outside.
The tube fit together, then, when the inner tube is pulled out the two lips meet and stop the neck flying apart.
When the head is pressed back down into the giraffe crate I had problems with some section going down too far so that when I tried extending the neck again the lips caught on the bottom end of the tube. To stop this happening I fitted an end cap to the end of the tubes with an air hole in the centre. Works a treat!
I've completed the model by making a box with lid and adding a giraffe head.
Blow through the hole and the giraffe pops out – at some speed!
Okay – so now I need to make some changes to the layout, for example I'm going to move the neck back a bit in the box to allow room for the head, then it'll be time for a bit of colour. Coming on nicely!