Opensource Rocket nosecone, transitions and couplers... OpenSCAD sketches.

Just in case it's useful I decided I'd chuck a few bits of openSCAD code I use to generate 3d models of transitions and nosecones and couplers for rockets onto github. I am no amazing coder but it's nice to opensource what little I can! Its pretty well commented so you just stick in the dimensions you need and render!

IT'S HERE!

Rocket Rail buttons... and shaving weight!

(Obligatory lathe shot above!)

In high power rocketry often a rail is used to launch the rocket rather than a simple rod as the aluminium tee slotted extrusion ( the same types that many 3d printer or hobbiest cnc router frames are made from) is more stable and rigid. This means that instead of a launch tube/lug being mounted to the rocket airframe a pair of rail buttons that slide into the slotted extrusion are added instead.

I struggled when I was building Panta Rhei for my level one certification to find out which rail buttons I needed or indeed the dimensions of the ones I needed as I hadn't ever been to a high power event. However I eventually discovered there are 2 types of rails commonly used, the 2020 rail with a 6mm slot or the 3030 rail with an 8mm slot.. Eventually a very kind UKRA member (driven mad by my constant questions) took pity on me and sent me a set of rail buttons that would fit a rail that would be used at the launch event I was aiming for.

They worked brilliantly and I've been doing a few experiments to make further rail buttons to try and shave the weight and also to be able to use a metric fit as the commercial ones use a 3/16 machine screw to fit them. People who know will know have a bit of a thing about using SI units... but also I think that the 3/16 screws with quite a course pitch thread when usually being fitted into 2 -4mm wall thickness they don't really offer an optimal thread type/contact area. So above is a picture of the commercial ones aimed to be used in a 6mm slotted 2020 rail.

Above is the first set I turned up, here I used Delrin which has a higher Young's modulus than nylon (which I believe the commercial ones are) and is very free to machine and also has a self lubricating quality as you can see about fitted with M3 12mm bolts (with a large head) offers almost a 2 gram saving over the originals.

So I also had a go at turning some out of Nylon and again they represent a weight saving over the originals even though the actual Nylon piece is slightly heavier than the original the M3 bolt weight saving makes a saving overall.

So I think the future is Delrin.. stronger and lighter!