Right I've Decided To Do A T Series Conversion

[Reg]

Just out of interest Reg where do you think it would fail? - I really cant work it out!

I didn't say it would fail, just I'm not comfortable with it as it is now.

 

The twisting forces that the brace bar you have modified has to cope with now have been transmitted to the weakest part of the wishbone ie: the middle.

 

Like I said before a shear plate 1-1.5mm thick stitch welded on top of the bit you chopped would make it much stronger.

 

Maybe I'm over the top in my judgement, but in the 9 years of my car being seriously abused off road and on track I've not had a single weld failure.............

 

Reg

[Phil.S]

Just out of interest Reg where do you think it would fail? - I really cant work it out!

I didn't say it would fail, just I'm not comfortable with it as it is now.

 

The twisting forces that the brace bar you have modified has to cope with now have been transmitted to the weakest part of the wishbone ie: the middle.

 

Like I said before a shear plate 1-1.5mm thick stitch welded on top of the bit you chopped would make it much stronger.

 

Maybe I'm over the top in my judgement, but in the 9 years of my car being seriously abused off road and on track I've not had a single weld failure.............

 

Reg

 

Oh OK. I'll weld the plate on the top then just to be on the safe side. Cheers for the advice.

Phil

[cmm_elise_s]

are you having a laugh?? replacing a tubular steel bar with some 4 mm plate??

 

 

Eh, no.

 

Isn't the entire design ethos of the Elise chassis based on the notion of replacing as much tubular steel with plate??

 

It's how you use the mateial - Simplicate, then add lightness (CC).

 

Looking at the original wishbone design, I'm inclined to agree with Phil that the cross bar in it's original position is largely redundant once fitted. Even if it was removed completely, I can't see how the wishbone would fail in normal operation?

 

It certainly helps spread any side loading across both bushes and would therefore help reduce wear, but it isn't adding a great deal of strength.

 

The cross bar helps to align the pivots, makes manufacture simpler / more accurate and gives the component added strength when being stored / transported / fitted.

 

To this end, I would suggest a 4-5mm steel plate would be more than adequate. I'm interested to know how you think this would fail given that it's only ever going to loaded in compression or tension? (Let's assume it's fully welded)

 

But hey, I'm no chassis designer so what would I know

 

Dunc

 

 

 

Basically the plate would be a thin web and could be subject to a fair bit of shear force thus bucking could occur. In addition the torsion on the plate would be greater than its capacity.

 

"...The cross bar helps to align the pivots, makes manufacture simpler / more accurate and gives the component added strength when being stored / transported / fitted...." Actually you will find the cross bar reduces the effective length of the other two bars, the potential bending moment induced into the member would be of a reasonable magnitude .....stops them pushing together when under force......etc etc plus the benefits you have given

 

I would have to carry out some calcs on this to check it fully. Of course I am making a few assumptions.

 

with regards to your comment about the ethos of the Elise...........the whole structure acts as one......this is a non standard modification............

 

I am not a chassis engineer either but I am a structural engineer who mainly designs STEEL structures.

 

 

 

to the chap talking about 1mm weld.............a 6mm FW is only good for 0.6kN/mm length of weld.......so.......enough said

 

 

 

anyway enough debating.....any more progress photos????

[dss123]

I am not a chassis engineer either but I am a structural engineer who mainly designs STEEL structures.

 

 

 

Ask a structural engineer what 1+1 is and he'll tell you 9 (just to be on the safe side).

 

 

 

 

Dunc

[Reg]

the chap talking about 1mm weld.............a 6mm FW is only good for 0.6kN/mm length of weld.......so.......enough said

 

Don't think anyone has mentioned a 1mm weld.....

 

I suggested a 1-1.5mm steel shear plate stitch welded on top of the tube that Phil has already welded in.

He would only use a 6mm plate if he was replacing the steel that he's already welded in, or was attaching something like a shock to it. (or if he wanted to make a APC).

 

Phil, if you want some professional advice, my mate makes chassis for a living. If you want his email address drop me a PM.

[cmm_elise_s]

makes or designs?

 

Phil, if you want some professional advice, my mate makes chassis for a living. If you want his email address drop me a PM.

[Elaine]

makes or designs?

 

Both.

 

E.

[richbk]

seems like you guys need to help phil with his exciting project,

 

not try and out do each other with tech knowledge

 

and i know naff all about steel , welds, plate or engines

 

just read last page of thread and i thought i'd jumped to seloc LOL

 

richbk

[dobbo]

just read last page of thread and i thought i'd jumped to seloc LOL

 

richbk

 

Harsh

 

 

 

 

but fair

[Ladders]

Yes, does have a bit of feeling of deja vu! (sp!)

 

Now if it was a honda, on seloc!

 

Thing is at least it's constructive critisim!

[cmm_elise_s]

'Fortunately' the Institution of Civil Engineers and Institution of Structural Engineers of which I am a member of both require my to inform people of safety issues relating to engineering works.

 

hence I have only tried to give a reasonable engineering judgment with my posts.

 

 

 

If I really wanted to be a smart arse I would have made reference to the angles of intersection between fusion faces of welding materials and how the strength of weld is reduce when you go beyond sertain angles.....but......anyway.............. .........

 

'not try and out do each other with tech knowledge'.........I though i was the only one who appeared to have technical knowledge............JOKE

 

 

seems like you guys need to help phil with his exciting project,

 

not try and out do each other with tech knowledge

 

and i know naff all about steel , welds, plate or engines

 

just read last page of thread and i thought i'd jumped to seloc LOL

 

richbk

[richbk]

LOL

 

only trying to put things back on track,

 

we have a wealth of knowledge on here and its great to share it, im sure phil appriciates everyones input..just not sure the tone of the posts was serving any purpose or helping what is a great thread...i saw it was up to 8 pages and thought he'd got it going and was reporting lap times from donny

 

anyway..

 

richbk

[Phil.S]

Donny lap times - LOL!!

 

Yeah I appreciate all the advice but its not worth squabbling over. I'll get the damn engine running this weekend and we can then move the topic on....

[Reg]

Spoke to my mate Chaz yesterday, he said he would use 1.6mm for this job.

He actually laughed when I said 6mm had been suggested....................

 

Phil, if you have a look at the plates on the front wishbone you will see they're nothing like 6mm, even if added together. There isn't any bracing between the plates either (unlike what you have done), so yours will be strong enough with 1.6mm.

 

No qualifications, I've just have made/modified many chassis (with no failures),

Reg

[Phil.S]

Spoke to my mate Chaz yesterday, he said he would use 1.6mm for this job.

He actually laughed when I said 6mm had been suggested....................

 

Phil, if you have a look at the plates on the front wishbone you will see they're nothing like 6mm, even if added together. There isn't any bracing between the plates either (unlike what you have done), so yours will be strong enough with 1.6mm.

 

No qualifications, I've just have made/modified many chassis (with no failures),

Reg

 

Thanks Reg