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3D bottom swing-arm for custom recumbent trike

February 13, 2025 — BarryK

I posted about exploring various 3D CAD apps, script-based then came back to SolveSpace:

...designed the top swing-arm for my custom trike.

If you look at my custom trike project, the swing-arms, also known as A-arms or wishbones, are welded steel and ball-joints:

"Solar-powered recumbent trike"
https://bkhome.org/nomad/solar-powered-recumbent-trike.html

I'm planning to put stiffer springs on the front suspension, and reduce the wheels from 20 inch to 16 inch.

But also there is this germ of an idea to create plans so anyone can build a similar trike, from scratch. Plan for it to be mostly aluminium, including the swing-arms.

Working toward that, want to model the entire trike in 3D.

Haven't taken my trike on any journeys yet, just ridden around locally. Have learnt a lot about the handling, which is why want the stiffer springs -- they are on order. Going around corners, I can see that stability would be improved if the trike can lean into the corner, so would like to implement that on the next build. Either that, or make it a quad.

Can't go off touring on the trike anyway, as having an eye operation soon, followed sometime after by a train journey.

This evening designed the bottom swing-arm in SolveSpace:

img1

...notice something a bit odd; there are two brackets to which the shock absorber will bolt, a choice of two positions, but you cannot see right through one of the holes. SolveSpace is having some kind of logic problem there. It doesn't surprise me, the complicated mathematics that SolveSpace has to analyze.

The bottom-arm SolveSpace file is here.

Posting this in the "light" category, as it could be the start of an entirely new traveling-light custom-trike project.       

Tags: light