Anyone weighed their bare chassis finished with all the paneling in place?


Care to share the details?

Graber

I worked this out once but cant remember the result!

Basically, you can work out from the book that its about 45 metres of tube in the car. You can also figure out the area of sheet pannelling.

Taking steel to be summat like 7.7 times density of water, and that a cube of water 100mm x 100mm x 100mm weighs a kilo, then a similar cube of steel will weigh 7.7 kilos.

so, if you work out the cubic area of steel in the chassis, you should be able to recon the weight, with a kilo or so extra for the welding wire.

anorak off.

atb

steve

quote:

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Originally posted by sgraber
Anyone weighed their bare chassis finished with all the paneling in place?


Care to share the details?

Graber

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Wow Steve, that was mega-anorak!

But entertaining nonetheless!

Thanks

Graber

Does the CO2 / Argoshield trapped inside the tubes make the chassis lighter or heavier ?
Ron's book said about 35lb in one of the pictures - no sussy brkts etc

Steve, what about the weight you save by grinding the welds flat?

I've got a strong suspicion that the figure of 35lb is a load of old cobblers. And the picture of RC holding a chassis is rubbish too - it's aluminium.

Kingr

quote:

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Originally posted by madforfishing
Does the CO2 / Argoshield trapped inside the tubes make the chassis lighter or heavier ?

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oh dear - 2 problems
1) weight reduces much more than mass does - overall you are less able to accelerate - think about trying to run with enough helium balloons so you only weigh 1 gram - you couldn't do it.
2) helium in tyres - tiny molecule - no viscosity diffuses like mad - your tyres would keep going flat....

Hi,
I weighed mine by standing on bathroom scales and lifting first the front and then the back and subtracting my own weight. I only lifted it a centimeter or so from the axle stands so this should give an accurate figure. I weighed just the bare chassis. That is only the welded bits but this included the 16swg steel floor and footwell end plates. All suspension mounting brackets were in place as well but no suspension components. There were still some small brackets left to attach.

Anyway the weight was just over 60Kg's. I think it was 65Kg's in fact but don't have the figures to hand - will double check tonight.

Note that I used 2.0mm thick steel tubing instead of the 1.6mm stuff because it was all I could get locally at the time. Also note that my car is a McSorely 7+4" design and has extra triangulation in place to handle the V8 engine and de-dion rear suspension.

I'd expect a book chassis to be around 50-55Kg's again for the basic chassis (as held up by uncle Ron in that picture.) 35lb's my ar$e!! Even in aluminium it must have been at least 35Kg's!!!

Hope this helps,
Craig.

BobC: if you filled your chassis with helium your car would be less massive and accelerate faster than if it was filled with air.. remember you're not just filling it with massive helium, you're flushing out the more massive air.

for optimum mass reduction you'd pump out the chassis to a high vacuum, but you'd have tricky sealing issues and perhaps introduce odd stresses.

plus this whole idea is silly. air has a mass of about 1.2kg/m^3, there's probably less than 500g of air in a chassis.

With my car its not the weight of the car that bothers me........its the fat twat driving it
Bob

This is what my chassis weighed with no panneling, no floor,no pedal supports, but all the brackets fitted
Rescued attachment Chassis Weight.JPG

What about rollbars? Weights above are for plain book chassis which doesnt include the rollbar as part of the frame does it?

Just checking cos mine weighed a fair bit more than that, ~100kg but it included IRS (which I think means more support at the back), big arse rollbar with supports down to bottom (rather than top of rear panel), welded in floor, footwell ends, all brackets (inc handbrake, steering rack, etc) and powder coat!

I design x-ray machines that work on density so this stuff kinda rubs off on you


a sheet of steel 2400 x 1200 x 1.6mm works out approx 35 kilos.


approx 45 metres of tube with 25 x 25 x 1.6mm is about 55 kilos. That agrees nicely with marks figure on the scales.

SO, assuming you panel the floor and the rear bulkhead with steel, that uses about a sheet and a half if i recall, so thats about 108 kilos all up.

way out from uncle rons figures!











atb

steve

quote:

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Originally posted by sgraber
Wow Steve, that was mega-anorak!

But entertaining nonetheless!

Thanks

Graber

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Hey Steve, what do you do for a living and is your car a standard one?

design morgans and make x-ray machines at home.

or somethign like that.

xray morgans and stay at home......I could live with that.


atb

steve

At this point in the build:



My chassis weighed between 80 and 90 lbs. It's very difficult to get the thing balanced on a bathroom scale, and I didn't want to attempt to hold it while standing on the scale, then weigh myself separately in the fear of finding out I've gained MORE weight.

I agree that the 35lbs figure in the book is complete nonsense. 135lbs at that point of construction would be more likely.

you cant ave built that, the workshop looks way too tidy! knock some boxes over and scatter some empty pot noodle pots here and there or no-one will ever believe you.





Russ.

Not an actual weight but is a calculation that includes all the tubes and all the panels in 16 gauge:-

I got 181 lbs for the complete book chassis with all steel paneling.

I also got 159 lbs for the weight minus the luggage region, i.e. everything forwards of the seat back tubes.

As my computer models are very simple the weights tend to be slightly overestimated due to something called "mass doubling" which means that a small error creeps in at every tube joint.

By the way I've seen a list of weights on the Fluke Motorsport site. I think I recall a Westy Seven chassis given as 184lbs bare.