"Monocoque"

[GrUmPyBoDgEr]

Monocoque = noun an aircraft or vehicle structure in which the chassis is integral with the body.
-ORIGIN French, from mono- "single" + coque "shell"

Taken from the Oxford compact English dictionary

The Lotus v. Spyder discussion continues & still provides great reading; I for one am continuing to enjoy it because new bits of information continue to surface both on the history & the engineering sides of the discussion.
Long may it live!

One point made within that discussion was the initial design of the Elan S1 body shell which has really interested me & rather than diversify the Frame/Chassis discussion I thought that a new thread about the development of the Body shell right from its conception would make an enlightening subject for history duffers like myself.

Mention was made of extremely strong S1 bodies that were supposed to be load bearing for all of the major components (suspension?) & that the sheet metal frame/chassis was added to overcome some shortcomings of that design.

I've not had any form of contact with any earlier Elans, my own experience being my one & only 1970 S4.
The S4 does not show any form of structural reinforcement that would provide any form of substantial component support.
The molded in bobbins used to attach it to the frame appear to be the only areas retaining any form of structural strength.

One of my once owned was an Elite Mk14 & that was one of the prototype cars so may have been quite different to those that later went in to production.
Nevertheless the body was what we would call a true monocoque design.
The whole thing was designed/built to carry all of the drive train & suspension components.
Depending on the loading the thickness of the fibreglass changed quite dramatically in order take those loads.

So, were those early Elan bodies really built to take such loads & subsequently altered after the "backbone" chassis had proved its worth?

Cheers
John

[rodlittle]

There was a discussion probably on here somewhere about bodyshell stiffness and why the boot lid was small on early cars and if I remember correctly Ron Hickman was quoted as saying that initially the boot lid was small to try and keep some strength in the body since it had no roof and the chassis was a way of curing all the stiffness problems,so I guess there were no production thicker bodies.
Of course what went on in development we shall probably never know now
rod

[ardee_selby]

There was a discussion probably on here somewhere...rod

Yes, Bill308 mentioned this:

http://www.type26register.com/articles/ ... date10.pdf

(From this thread:
elan-f15/how-about-stainless-steel-chassis-with-extra-features-t12698-15.html)

I would like to hear Mr. Mike Ostrovs take on this subject from what I've read of his hybrid Elite/Elan experiences.

Cheers - Richard

[garyeanderson]

I would love to see the original drawings that they were working with. My guess it that
they may have thought a Tubular structure for the front and rear "monocoque" subframes.
I believe that the 16 bobbins that are currently molded into the bodies were there to
mount the current "sub chassis" and would have been used with the
separate "subframes". look at how complex the molding tools were to create the
type 26 under side.

photos are of mid 1965 lotus molded body.








My guess is the tunnel not being boxed was a problem and a molded belly pan
(third molding) wasn't part of the plan and the open box suffered from that and
other issues. I believe that Frank Costin did an open monocoque later on and took
some creative thinking of where the strength was obtained from.

[rodlittle]

Just how many elans do you have Gary?
rod

[GrUmPyBoDgEr]

Ah yes the boot lid explanation sounds good also those ribs along the bottom of the car may have helped but they do appear to have some interruptions along their length, which would not have helped.
I'm sure that someone mentioned that the early/first S1 bodies were a lot thicker than later ones & those comments & my memories of the Elite were really what sparked me off on the monocoque thoughts.
So it seems that suitably strengthened i.e. locally thickened S1 bodies did not enter production or get sold?

Cheers
John

[GrUmPyBoDgEr]

There was a discussion probably on here somewhere...rod

Yes, Bill308 mentioned this:

http://www.type26register.com/articles/ ... date10.pdf

(From this thread:
elan-f15/how-about-stainless-steel-chassis-with-extra-features-t12698-15.html)

I would like to hear Mr. Mike Ostrovs take on this subject from what I've read of his hybrid Elite/Elan experiences.

Cheers - Richard

Richard,

as far as I can remember he used a stretched Elan frame together with the rest of the Elan drive train & suspension which he fitted into the big hole he'd carved out of the Elite body shell.
Provided the marriage was done properly the result must be very "Stiff"!

I know a guy in the midlands who has spent years collecting all of the right Elan bits (including a stretched frame) to fit into an unused Elite body.
As far as I know he's not started properly on the project but enjoys talking about it

Cheers
John

[elansprint71]

In Robin Read's excellent book "Colin Chapman's Lotus" the story of th Elan's difficult gestation is very well documented. All ideas of load-bearing plastic was abandoned well before production started.
Best Lotus book you've never read.

[ardee_selby]

In Robin Read's excellent book "Colin Chapman's Lotus" the story of th Elan's difficult gestation is very well documented. All ideas of load-bearing plastic was abandoned well before production started.
Best Lotus book you've never read.

Does it also explain why Lotus chose to bond body & chassis on S1 Europas'? And was it being leant on by insurance companies that brought about the change?

Cheers - Richard (BTW re: "I'm going to take myself off to an island and not going to post for a week". Your week isn't up yet, so s*d off! )

[GrUmPyBoDgEr]

In Robin Read's excellent book "Colin Chapman's Lotus" the story of th Elan's difficult gestation is very well documented. All ideas of load-bearing plastic was abandoned well before production started.
Best Lotus book you've never read.

I did read it a long time ago; I think

[elansprint71]

In Robin Read's excellent book "Colin Chapman's Lotus" the story of th Elan's difficult gestation is very well documented. All ideas of load-bearing plastic was abandoned well before production started.
Best Lotus book you've never read.

Does it also explain why Lotus chose to bond body & chassis on S1 Europas'? And was it being leant on by insurance companies that brought about the change?

Cheers - Richard (BTW re: "I'm going to take myself off to an island and not going to post for a week". Your week isn't up yet, so s*d off! )

No idea about those cars with the engine at the wrong end.
Thought that I should keep an eye on things just in case.
IPhone, eh? Blessing or curse? Discuss.

[garyeanderson]

Is it dead?
Why does this topic deserve flushed?
No one interested in Elan history?

Sad

Gary

[ardee_selby]

<snip> No one interested in Elan history?

Yes, of course...and it's just cost me yet more ????'s to get hold of the book mentioned...

(i.e. Colin Chapman's Lotus by Robin Read) It had better be worth it!

Cheers - Richard

[GrUmPyBoDgEr]

<snip> No one interested in Elan history?

Yes, of course...and it's just cost me yet more ????'s to get hold of the book mentioned...

(i.e. Colin Chapman's Lotus by Robin Read) It had better be worth it!

Cheers - Richard

Well whilst you're in the spending mood Richard, go ahead & order "Colin Chapman Inside the Innovator" by Karl Ludvigsen; that is, if you don't already have a copy.

It's a real myth-buster & covers many technical subjects.
Having said that, it is pretty heavy going & I put my copy down having only read a few of the many interesting capitals some time before moving home took over my life.

Cheers
John

Oh dear now we've drifted off topic again, how on earth does that always happen

[trw99]

Gary

Plenty of us are interested in the history of the Elan! To help row this discussion along I delved into my books and came up with this brief Elan body development time frame. It may be wrong but if anyone can expand on it then please feel free.

1958/9 the backbone conceived

A mule, known as M2, was built to test the backbone mechanicals using a proprietary Falcon Sports Car glass fibre body shell. Harvey reports this bore the badge ?AC Special? and was driven more than 50,000 miles in 18 months, then disassembled in 1960. This worked well enough for the decision to go ahead with a pre-production prototype Elan

November 1961 Hickman makes first airbrush rendering of Elan body; clay models were built soon after

Williams & Pritchard were called in to help with building the master body moulds. Bolster contends that the bodyshell was virtually an unstressed member, though it contributed to the torsional stiffness when bolted down

Early 1962 the first bodyshell was fitted to a backbone chassis

Jul/Aug 1962 tooling and production orders made by Purchasing Director John Standen

1962 John Thompson Motor Pressings of Wolverhampton given Lotus contract for the backbone chassis

9 October 1962 Bourne given the order for bodies by Lotus

17 October 1962 Elan shown at London Motor Show

May 1963 First production Elans delivered to dealers

Hickman attributes the commercial success of the Elan to:

1) the then state of the art Unimould body manufacturing process, attributed to John Frayling and developed by Hickman and Albert Adams;
2) the bonded in bobbins designed by John Westell of Maximar and refined for production by Hickman;
3) the cheap to make backbone, entirely Chapman?s idea;
4) producing a professional looking car body whilst using other makers parts

I have attached a photo of a Falcon to give those of you who like to be able to see these things the chance to do so! I have some snaps of Elan styling models taken from a Supercar Classics magazine article on Hickman. However, I have never seen a photo of the mule or the Hickman airbrush renderings. Anyone have them?

Tim