1970 Vespa 50s electrification project

General Discussion about large electric scooters and motorcycles and other things with no pedals.
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EddySPalm   10 W

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Re: 1970 Vespa 50s electrification project

Post by EddySPalm » Sep 19 2018 12:49pm

TilmanBaumann wrote:
Sep 19 2018 10:37am
Hi,

how did you determine the material and thickness requirement for your swing arm? What steel and thickness did you use?
I'm building one right now, and I think I'm building a tank. :oops:
I honest to god started with a 10mm thick 80mm wide flat section of steel.

photo_2018-09-19_17-43-37.jpg

If I don't fsck-up the welding I can use square tube for the arms for sure.
Hey,

First of all, you need to design the swingarm so that the forces from it's surroundings (mostly reaction forces from the shock and brake) yield as little bending and twisting as possible. Compression, tension and shear (to a certain degree) is favourable.

Square and round (or simply hollow) sections are brilliant because they can handle forces in most directions.

So if you make sure your forces are not acting with an offset to whatever your chosen section is, and if you keep your lengths of flat stock to a minimum (very prone to twisting, and even buckling) you're probably onto something!

Hope that gave some kind of general, boring answer 😅

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EddySPalm   10 W

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Re: 1970 Vespa 50s electrification project

Post by EddySPalm » Sep 19 2018 12:53pm

Btw my sections are from mild steel, 355MPa yield, all 2mm thick.

The front is 40mm round tubing
The middle pieces are 40mm square, and
The rear pieces are 40x20mm rectangular.

TilmanBaumann   10 W

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Re: 1970 Vespa 50s electrification project

Post by TilmanBaumann » Sep 19 2018 4:44pm

I think I will use some 40x20 section as well. (Stainless I think)
Gives me some girth and is way lighter. I can always tack stuff on it it wobbles.

Thanks for your help.

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EddySPalm   10 W

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Re: 1970 Vespa 50s electrification project

Post by EddySPalm » Sep 20 2018 1:57am

I reached a milestone today, and sent the swingarm in for final welding!
I used last night to drill and file out a slot for the spherical bearing cup to be welded in, and I got it both further back and up than I thought I would, so super happy with that. The welder at my local machine shop said he wouldn't have time for it anytime soon, but I'm alright with that.
Some pictures from yesterday evening:
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EddySPalm   10 W

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Re: 1970 Vespa 50s electrification project

Post by EddySPalm » Sep 20 2018 2:01am

Ohh and a little delayed bonus shot from the FLUKE IR thermocamera, showing maximum temp on the BMS during our 100A run. That's 56 degrees C.
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