smart51
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| posted on 19/11/07 at 01:29 PM |
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steel for chassis
What kind of steel should I use for my (non-seven) chassis? The whole thing will weigh 250kg when built.
I was thinking of 25mm OD, 1mm wall thickness, with 19mm OD for bracing. My local metal supermarket only do imperial sizes but are cheap and
helpful.
They have 1" in 0.889mm wall thickness and 1.2446 mm thickness. The latter is 25% heavier than I'd budgeted for. is 0.9mm too thin? Am
I better off finding some slightly lighter metric tube?
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Phil.J
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| posted on 19/11/07 at 01:46 PM |
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250kg? You must be extremely optimistic or have some very good manufacturing facilities! My bike engined hill climb single seater weighs 272kg with a
tub weighing only 16kg, and it's amongst the lightest in the class.
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smart51
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| posted on 19/11/07 at 01:54 PM |
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The 250cc scooter engine and transmission is 36kg complete, which includes the trailing arm, clutch and brake. The chassis, made from 1mm wall tube
and 3mm mounting plates would weigh about 27kg painted. 10" wheels and tyres are also light, especially as there are only 3 of them. OK, 250kg
is a tough target, but with weight, aim low.
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t.j.
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| posted on 19/11/07 at 04:57 PM |
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I'm probably building a tank!
i'm using 25x25x2mm all around.
grtz 
[Edited on 19/11/07 by t.j.]
Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)
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toady
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| posted on 19/11/07 at 07:53 PM |
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Thats what I'm using as well. Perhaps we'll have to start a "tank" club.
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cjtheman
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| posted on 20/11/07 at 04:48 PM |
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me too 25x25x2
can i join your tank club
wanted
sunny weather
sva pass 12/6/09
taxed 16/6/09
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blueshift
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| posted on 21/11/07 at 08:39 PM |
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Weird, is 2mm the fashion now?
Why not 1.6mm, has anyone suggested it's not strong enough? I find that hard to believe (n.b. I am not an engineer).
smart51, if you're asking those kind of questions on here, are you sure you know enough to design a chassis strong and safe enough?
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smart51
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| posted on 21/11/07 at 09:31 PM |
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I'm happy enough with the shape of the chassis, it is somewhat inspired by the locost chassis. What I want is some soothing or warning words
about wall thickness.
Previous posts suggest 1.25mm wall is fine but I've not found an opinion on 1mm or 0.9mm. I'll probably use 1.65mm wall for tubes that
directly bear suspension loads, but am not sure about the other tubes.
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Mark Allanson
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| posted on 21/11/07 at 10:45 PM |
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I would have thought 1.6mm for a passenger cell and the same for front and rear subframes/pickup tubes and 0.9mm (20g) connecting it all together. If
in an accident, the subframes will collapse intact onto the cell and absorb all/most of the energy.
1.6mm is proved strong enough for the suspension pickups, and something only weighing 250kgs will hold together with 0.9mm walled tubes as it is
mainly the shape and location of the tubes, not the wall thickness which gives the strength.
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Angel Acevedo
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| posted on 26/11/07 at 12:01 AM |
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quote:
Originally posted by t.j.
I'm probably building a tank!
i'm using 25x25x2mm all around.
grtz
[Edited on 19/11/07 by t.j.]
Tank??
That`s a light armored vehicle,
mine will be (eventually i hope) 38 x 38 x 14 ga....
Beware of what you wish.. for it may come true....
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