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Author: Subject: TR6, 4 and 2 Do they need to be round
VinceGledhill

posted on 3/9/03 at 09:39 AM Reply With Quote
TR6, 4 and 2 Do they need to be round

I have been coming along well with my chassis. I have not yet got any round tube for the triangulation pieces of TR6 TR4 and TR2.

I do however have some square box section left over from the tunnel section. (Doh... ordered 2 x 6m lengths)

My quesion is this. Could I safely use this 3/4 x 3/4 box section instead of round? Does the round have some magical proporties? Just seems a shame to go buying more steel and storing a load that I haven't used.





Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983

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ned

posted on 3/9/03 at 11:31 AM Reply With Quote
Vince,

I'm going to use square tube, and have seen other chassis with square tube here too.

I might use 1" as opposed to 3/4", anyone know if these tubes are mainly in compression or tension?

Cheers,

Ned.





beware, I've got yellow skin

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timf

posted on 3/9/03 at 11:38 AM Reply With Quote
if you look at cimtrix's post re stiifnes he recommends that they should be upped to 1" either sq or round

see here
http://forum.locostbuilders.co.uk/xmb/viewthread.php?tid=5810

[Edited on 3/9/03 by timf]

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James

posted on 3/9/03 at 12:04 PM Reply With Quote
quote:
Originally posted by VinceGledhill
I have been coming along well with my chassis. I have not yet got any round tube for the triangulation pieces of TR6 TR4 and TR2.

I do however have some square box section left over from the tunnel section. (Doh... ordered 2 x 6m lengths)

My quesion is this. Could I safely use this 3/4 x 3/4 box section instead of round? Does the round have some magical proporties? Just seems a shame to go buying more steel and storing a load that I haven't used.


Making them square is fine.

When it comes to TR1/2 (the two engine bay tubes) then 1" seems to be the order of the day- especially if you've re-inforced the nosecone area as per Cymtriks plans because greater forces are transferred as a result.

HTH,

James

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VinceGledhill

posted on 3/9/03 at 12:24 PM Reply With Quote
Thanks for that guys. I've got some 1 inch tube left. (only a Z tube to do) so probably will have enough to finish it off.

Nothing magical about round then?





Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983

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svinto

posted on 3/9/03 at 12:51 PM Reply With Quote
Nothing special, other than it might be easier to weld because of the tight angles...
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stephen_gusterson

posted on 3/9/03 at 01:06 PM Reply With Quote
I used 1 inch sqare, and on my car, made an 'X' brace instead of just one diagonal.

However, be careful if you try this cos on my car one of them projects outside the flat panel that would form the side. Im talking of the engine bay section. Not a problem on my car, I just slightly angled the panels. This wont be seen as a morgan look alike has body panels over the innner ones (wings and running boards) anyway.

Just be sure that the tube doesnt extend outside of the 'flat' area, unless you want a curved look.


atb

steve

[Edited on 3/9/03 by stephen_gusterson]






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JoelP

posted on 3/9/03 at 02:44 PM Reply With Quote
surely round is less likely to crush? ie go flat and fold?
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ned

posted on 3/9/03 at 02:51 PM Reply With Quote
i'd *guess* the round tube may be better in tension, but in compression a larger diameter/section of tube should be stronger.

I'm sure someone will correct me...

all IMHO

Ned.





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VinceGledhill

posted on 3/9/03 at 03:24 PM Reply With Quote
I'll do the TR1 and 2 in 1" square. And the others in 3/4 inch square. May add a diagonal to the passenger foot well too.





Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983

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cymtriks

posted on 6/9/03 at 07:32 AM Reply With Quote
All the TR tubes are a bit small for their job. This is especially true for TR1 and TR2 which are realy only suitable for smaller engines and lighter cars.

A proper finite element analysis of the lowcost chassis shows that the most highly loaded tubes are those that connect the front and back of the engine bay. Of these tubes TR1 & 2 are the longest, the thinest and carry a high load.

I'd suggest 16g 1 inch square or 14g 1 inch round.

Take a look at my chassis design in the photos section. The double Y brace across the engine bay is very effective and much better than any other way of getting the tubes around a wide engine. The chassis design shown is over twice the book chassis stiffness, about the same as a Caterham chassis and not far behind an ultima chassis in stiffness terms. You'll need to scroll back through my earlier posts to get all the details of the modifications.

Hope I'm not too late to help!

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VinceGledhill

posted on 7/9/03 at 09:51 AM Reply With Quote
Thanks for the advice cymtriks. I've done one side of the engine bay which is in 16g 1 inch square. The other side is yet to cut.

The Y section engine bay modification looks great. I'll certainly add that because I've not done the "R" tube yet anyway.

Ref the Y tube, I'll form a 90 degree bend with two 45's intersecting at the centre of the Y. Therefore the two top parts of the Y as you look at it will be the same length. The lower part of the Y cut and made to fit.

If this is not suitable then please let me know. Otherwise I will just get on with the job this afternoon.





Regards
Vince Gledhill
Time Served Auto Electrician
Lucas Leeds 1979-1983

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Mark Allanson

posted on 7/9/03 at 12:03 PM Reply With Quote
Variation on a theme Rescued attachment YBrace.JPG
Rescued attachment YBrace.JPG

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