Plywood for suspension?

[mike_o]

I'm considering building a lightweight, low power ( 2 x 3 KW) kart-like vehicle. Gokart wheels, independent rear drive shafts, dual belt drive BL motors and dual ESCs with steering vectored "electronic diff". Each motor drive, shaft, brake and wheel bearing mounted in identical stiff, boxes/frames for screwing down on a plywood chassis.

Now the question: How about building the chassis with a flexible, transversal "tongue" on which the drive boxes are mounted? This would provide a little (pendulum) suspension movement. Not much, don't want to upset the camber, and don't want to break the plywood. but enough to add to the inherent tire "suspension/absorption".

Is that viable? I know the flexing properties of plywood is a design parameter in boat hull design, but it probably flexes less than what I intend. Fatigue cracking?

thx, mike

 

[Papa]

Sure it would work, but I'd suggest using carbon fiber leafs instead - and unlike wood, impervious to moisture. The Corvettes (and perhaps others) used CF leaf springs. You can easily fabricate your own by layering (and alternating weave patterns) to achieve the desired results. CF also has excellent damping properties.

 

[PaPaSteve]

One of my previous work mates designed and built a few plywood gokarts.
The method of assembly was interlocking 3/4" plywood and used a waterjet to cut the parts.
Several of the guys used to post their after hours projects on instagram under the title
"safetythirdbuilds"
You'll find a glimpse there.

 

[Chalo]

The Corvettes (and perhaps others) used CF leaf springs.

Those were fiberglass, which is another applicable material choice. Pultruded fiberglass bars make excellent leaf springs, with the fibers oriented longitudinally.

 

[Papa]

Those were fiberglass, which is another applicable material choice. Pultruded fiberglass bars make excellent leaf springs, with the fibers oriented longitudinally.

Oops... I stand corrected. The ones I installed eons ago were black, so just ignorantly assumed.
Snow skies can also be butchered and used for suspension parts. I see'em all the time littering secondhand stores.

 

[amberwolf]

A number of poeple have used skis and snowboards for leaf-spring suspension. I was going to do this but never got around to it (I don't have the skis anymore to try).

Leaf Suspension using Skis

I got these as a random find a few days ago: http://www.endless-sphere.com/forums/viewtopic.php?p=306463#p306463 and took them home because I have been pondering whether sections of skis could be used as leaf springs, either single- or double-ended, for at least a trailer if not a bike or...

endless-sphere.com

 

[mike_o]

Thanks for the inputs! Sounds like I could start out with plywood and if the thing is a success and the plywood proves to weak, it could be upgraded to fibreglass. Or inforced with it.

 

[A-DamW]

Couple of links for fun:
The Recumbent Bicycle and Human Powered Vehicle Information Center