Beate's old Go-One 3

[freebeard]

It once was five posts. You can stutter your way from 11 to 15.

Someone should fabricobble a transverse composite spring. ....integral to the monocoque as a deformable structure.

[redneck]

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Welcome.

We have a member with the same velo as you.

https://diesel-bike.com/Aurora/aurora.html




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[Autobahnschleicher]

Originally Posted by freebeard

Someone should fabricobble a transverse composite spring. ....integral to the monocoque as a deformable structure.

The E-Ei uses that kind of front suspension, an interesting way to save weight, however it does lack adjustability and is not exactly cheap to manufacture.
The implementation of a Macpherson strut here seems a good idea for that reason.

[beate]

You can replace the springs in the struts by elastomeres.

That specific GoOne has a problem with the 2nd of the two idlers. For some unknown reason the chain is not guided anymore if the two or three innermost chain rings were used. I did not notice that when i bought the bike - the deraillor had been adjusted simply to block these gears. That must have been done long ago by one of the previous owners (it had been sold quite often). The majority of the GoOne 3s apparantly did not have that problem.

Workaround / solution: implement an idler that can move sideward with the chain. You'll find that in many recent velomobiles.

Here my modification - i still need to give it another 2mm toward the right, but i can at least use all gears.



BTW: i was aware of the Aurora project, but unaware that the owner is a momber of this community.

[freebeard]

I remembered the search term I struggled with at #11; duckduckgo.com/?q=compliant+mechanism&ia=web

[beate]

Transverse composite springs are actually used in the scene - see for example this quad (and a few other developments by that company):



You can even put a shell on it (a study by the developers which will not go into production)

[beate]

Back to the Go3:

You remember my remark on the stiffness of the rear swing arm?
The swing arm is NOT carbon fibre as many people believe. It is glass fibre. I gave it experimental stiffening rods made from wood - spruce, lightweight and comparatively stiff:



Fitted into the arms of the swingarm and glued with elastic PU glue (Sicaflex 201)



This noticeably reduces movement toward the side, but of course has almost no effect on torsion of the arms (which i understimated). Which leads me to the conlusion that i will need to replace them by carbon fibre bodies filling the full height of the swing arms as well. Not in winter, and i need to learn to work with carbon fibre.

[freebeard]

Nasty stuff needs vacuum bagging. IIRC the first bamboo bike frames came from calfeedesign.com/bamboo/. Their claims:

Bamboo Benefits:
Our most crash tolerant frame
Amazing vibration dampening
Stiffer than many carbon frames
Low carbon footprint
Functional work of art

Then there is Basalt. Similar performance as carbon fiber, but it isn't as brittle.

basalt.world/en/time-expands-its-range-of-bikes-made-using-basalt-fiber/

One could combine bamboo space frame with basalt tape joins.

[Piotrsko]

Doesn't need vacuum bagging unless you're a lightness freak. Is nasty since the fiber pieces are sharp and prone to breaking off , going aerosol and embedding in soft tissues then getting infected.... S glass is ~almost as strong.

[beate]

vacuum bagging is way too complicated for my possibilities (no workspace, work either deep in the night in the garage or in my 1 room appartment).

The strength of glass is unfortunately not sufficient in this application. As the fork clearly shows. The only alternative might be a well thought construction of (european!!!) birch plywood, which has about half the strength of glass laminate but a third of the density, so a sufficiently strong construction will be more lightweight.


(The parameters of concern here are Young's modulus and density)