Kit Vs Manual

[Blatman]

Westfields are space framed cars. AFAIK, whether it's for racing, or the road, the engineering principles for space framed cars are the same. I may well be being overly cautious about the panelling, but there is little point in saying that it'd be OK to do it on an uneven surface using axle stands, g-clamps and some guesswork, when I have information that tells me it would be less than sensible to do so.

We seem to agree though, because you say

as long as you are not sat on one side leaning over with all your weight on the chassie and putting one rivet in after the other in a line

.

That is what I meant by

A small deflection at one end while you lean in to get someting rivetted could be magnified at the other end.........

I was going to panel the outside of my chassis this winter, but it's a job that even my well qualified engineer will not attempt. "It's just not worth it. The risks outweigh the benefits" was what he said, after I'd tried every reason I could think of to see if it could be done to a decent standard.  I have no reason to doubt his advice, so I'll be taking his advice to not do it.

[Al Yupright]

I was going to panel the outside of my chassis this winter, but it's a job that even my well qualified engineer will not attempt. "It's just not worth it. The risks outweigh the benefits" was what he said, after I'd tried every reason I could think of to see if it could be done to a decent standard.  I have no reason to doubt his advice, so I'll be taking his advice to not do it.

So you're going to completely strip it to a bare chassis, trailer it upto the factory and plead with them to do it on the jig?

...hehehe should be an interesting conversation, and a big bill!

If you were to drive two identical cars, one which had been panelled in a jig and one which hadnt, I'd be amazed if you could tell any difference.

Cheers,

Al

[Phssthpok]

I'm with Blatman on this. To me it's common sense, you've got a flexible frame to which you're fixing sheets of alloy that only flex in one direction. If they're bonded on out of true then so is your frame. This might well explain why some builders have atrocious panel fit no matter how much care they lavished on trying to make the body work symmetrical. As for handling, I think what tends to happen is the discrepancies that result from misaligned panels are adjusted out when the car is set up; obviously not an ideal solution.

[stu999]

I also agree with Blatman's theory on this. However, as long as sensible precautions are taken by the home builder, I cant see it creating a problem. The addition of panels do give a lot of longitudinal rigidity to the chassis and the time taken to ensure all the holes are drilled the correct size and de-burred, and the panels are bonded with a good adhesive sealant is of far more importance. After all, the chassis shouldnt be  that flexible to begin with.

As stated, with racing car construction every little helps in terms of rigidity and perfect alignment, but considering that the average production car, even with modern production techniques, is built to a surprisingly large tolerance.

Not really a comparison, but the old Renault 4's etc had a wheelbase that was over an inch shorter on one side (the rear torsion bars to the radius arms overlapped, so the rear wheels were staggered). I cant remember many races being one by 'em, but they drove OK. For a french car.  

[Matt Seabrook]

well qualified racing car engineer, was that panelling the chassis in a jig would be highly desirable. Buying panels and doing it in the garage was pointless, to the point of foolishness............

Blatman me old mate perhaps you should let Westfield in on your insight as they are clearly lacking in this department then if the fit panels without it being in a jig. In an ideal world the chassis would be perfectly true but I have today measured the corner weights of my car and from best to worst there is less than 1% difference and I fitted the panels myself on piles of tyres. I think a fat b*****d like me getting in the drivers seat is going to twist the chassis weather it has been jigged or not. You said about me nit picking the other day about under bonnet temp I think that makes us one each. IMHO I think that getting the cars geometry set up correctly will make a far bigger difference then jigging the car up to fit the alloy panels but then I am not an expert so I will shut up now.

[Blatman]

Al.

Yep, I doubt I could tell the diffrence, BUT, until I try, I don't know.........Stripping the car and rebuilding it is free, 'cos I'd do it myself. I have a Minno, so transport to and from the Factory is petrol costs. I still don't know for sure if the Factory use a jig...........

Matt.

My theory is sound. IF a Westfield chassis is stiff enough not to be hampered by fitting ally panels by resting the chassis on a pile of tyres, then my theorising (and received advice) is rubbish. My engineer friend has been with me ever since I got my first chassis, and knows his business very well. He says that chassis flex is an issue that is not to be underestimated when undertaking this sort of work.

And yes, you probably could dial it out with suspension tweaks, BUT this could mean that the handling is always going to be compromised. You may end up with spring platforms at different heights on each corner. I can't see many people being happy with that, especially the perfectionists out there.

As for letting Westfield in on my insight.....they read the boardroom, so they'll be seeing this and either laughing at my stupidity, or changing their MO (after suitable investigation, naturally). FWIW, if I was production manager at Westfield, every car would be supplied with ALL ally panels ready fitted, and it would be done in a jig designed for the job. It wouldn't be an option..........

I could help them with the XTR2 front end downforce too, but I'd want a consultancy fee for that...........

Is that the 'phone..........        

[Al Yupright]

Yep, I doubt I could tell the diffrence, BUT, until I try, I don't know.........I still don't know for sure if the Factory use a jig...........

Aye! Make sure they'd do what you wanted and not just do it like all the other cars. Anyone know how many jigs they've got? I guess there are a fair few variations? SE, SEi, SEW, SeiW, Race, Mega, V8, MT75, Type9. So I wouldnt be surprised if they've only got one or two jigs for each variant, and hence the jigs are in use for chassis manufacturing almost all of the time. So might not be easy to persuade them to do your panels?

Maybe they do the works race cars panelling on there, if they think theres anything in it?

Any ideas what c******m do? Do they skin them on the jigs at Arch?

On the chassis flex, my orange car has the detachable petty strut, so I've just fitted that to see if I can feel any difference driving with that in it. Goes from the rollbar to the passenger footwell, so that should help reduce/change a lot of chassis flex.

I take it you have caller ID, Blatman!  ;-)

Cheers,

Al

[Blatman]

Caller ID.......arf.........

At the last factory open day (over 12 months ago now) I recall having a look at all the production bays and various jigs. I don't remember how many work bays and jigs there were, but the over riding memory is that there were quite a few.

For anyone reading this who was having similar thoughts, at least they have a chance to call the factory and ask them if it's safe to panel the chassis at home, or what would be the best way to ensure accurate panel fit, and not twist the chassis. It's definitely gotta be worth the call...............

[Richard M Green]

Can I drag this conversation, and peoples' memories, back to the day when you brought the new chassis back from the factory:

And what did we all (well most of us) do? Yep, sat it on a pair of the factory's trestle stands. One under the nose at about where the engine mounts are, and one under the rear chassis member.

And how much did it bend (droop) in the middle by? Very approximately; about the square root of eff all.

Now if Haxsaw wants to help us out (and cure his own worries about not having a jig) he could make the measurement for us all, on his new chassis, with the aid of a dial gauge and a jack, but I reckon adding an extra 20kg point load in the midst of that suspended chassis will still not inflict any measurable deflection - and that 20kg represents a helluva lot more than the self inflicted weight of the spaceframe at that distance.

Put simply: If your chassis bends under its own weight, then take it back to the factory and ask for one that's been welded rather than paper clipped.....

Stands back and waits to be flamed.

Regards all

Richard

[Blatman]

Succinctly put.

I'm off out to buy some ally panels, some rivets and some silocon(e) sealant. I shall return to my car with my engineer, tell him to stop being such a scaredy cat and get on with it........

[Richard M Green]

Noooooooooo!

May I suggest don't use silicon. Try to find some PRC in your area. Made by PRC DeSoto in the wilds of Oop North. It's a two pack epoxy used for bonding aluminium panels such that the rivets are virtually superfluous. Ideally a B2 compound will give you a sensible compromise of working viscosity and cure time.

Beware: it sticks like you would not believe. MEK acts as a solvent until it has cured. After that it's resistant to virtually everything.

Both the Westies that I have built were assembled (glued together?) using the stuff.

Regards all

Richard

[Blatman]

I presume I'd have to strip the powder coating from the mating faces of the chassis, and key the surface.....

Silicon(e) would *just* be for weather proofing, rather than structural bonding.

[Richard M Green]

No, PRC is not intended to be used on bare metal. In fact, all that you will need is etch primer on the aluminium panels, and a decent de-greaser such as MEK on the powder/epoxy coating.

[Mike H]

Blimey that PRC sounds nasty!

But would Blatman be able to replace his panels ever again? I've heard of people using stuff like that before, sounds a bit too permanent for me. As the rest of the car is bolted/rivetted together I think I'll stick with rivets and silicon for now.

Would PRCthingymajig be good for bonding cycle wings to brackets? I know that particular subject has been done before on here, but if PRCthingymajig is 'the dogs' then I may use that instead of Wurth.

I picked up my kit on Saturday, just need to find a decent powder coater now.

My panels were also ready drilled which I guess has saved me a lot of time measuring stuff.

But I'm still a little confused, should I get the panels etched before coating or not? - sorry wrong thread!

many thanks for all the 'advice'

Mike

 

[Mark Stanton]

I picked up my kit on Saturday, just need to find a decent powder coater now.

Give Cat Motorsport a call