The Fool on the Hill

The Fool on the Hill

Learning from CAD

By Simon Brooke || 10 September 2025

Learning from CAD

As I reported in my last essay on the tricycle project, I now have a CAD tool which I'm learning to use. So, learning to use it, I'm beginning to be able to visualise the tricycle, if not yet concretely, at least as an assembly I can look at and study. And doing that brings up several things.

That removable subframe

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Details, details

By Simon Brooke || 3 September 2025

Details, details

Thinking about how the tricycle will go together means thinking about a lot of details. One of the first thing that needs thinking about in detail is the four-bar linkage, since if that does not work the whole idea does not work and there's no point in investing quite a lot of money in laying up the hull.

Early CAD drawing of the four bar linkage

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Drawing the tricycle

By Simon Brooke || 2 September 2025

Drawing the tricycle

Current working SVG drawing of the tricycle

I have, as I wrote in my last post, real difficulty with learning 3d modelling software. Every system I've tried has a really steep learning curve, the commercial systems are extremely expensive making them very hard for me to evaluate, and some of my cognitive quirks just get triggered when trying to use them.

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Things which are blocking the tricycle project

By Simon Brooke || 25 August 2025

Things which are blocking the tricycle project

The tricycle project is extremely experimental and ambitious. It may not work at all. It may work technically, but I may not like it. It may work technically, but I may not be well enough to make use of it. If I commit to it, it will cost all my spare resources of both time and money for probably a year.

So let's once again lay out the things which are, for me, at present, blocking it, and consider whether those are reasonable; and, as part of that process, consider the steps and milestones which are needed to achieve a working vehicle.

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Rethinking the tricycle drive train

By Simon Brooke || 24 August 2025

It's almost a year since I last wrote anything about the tricycle project, but I haven't fortgotten it. Today, I've been rereading my posts on the design, and especially this one. I've been looking again at this picture, of Seventy Seven's removable front subframe which carries its front wheel, steering, and transmission systems; and I've been thinking. This will be a short post documenting my thoughts.

A largely carbon fibre subframe, carrying a bicycle transmission and steerable front wheel, with an extremely large chainring but relatively small wheel.

Firstly, the removable subframe is a win: it makes it so much easier to work on, and to replace if necessary. The downside to that is that there must be a weight and strength cost to having it removable.

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