Elan Chassis / MX5

[Keith Walker <100662.3423@domain.elided>]

>>One more time: the Lotus Elan had a "sort of a unit body with a very
clever STEEL
bracing structure that tied the engine and tranny end to the rear end." The
backbone
that we're going on about here, in other words, was emphatically NOT an
"original and
brilliant" piece of work by Colin Chapman, but rather a bracing
substructure developed
by one of his engineers to make viable the otherwise inadequate plastic
unit body that
Chapman mulishly insisted on developing for his open-top Elite
replacement..<<

Not really. The Elan was originally meant to have a fibreglass monocoque
construction
but when they were developing it they knocked up a mule using a steel
backbone
chassis. This worked rather well, so got developed into the production car.
The same
style of chassis has been used by quite a few other makers as well (some
probably
predating Lotus use of the idea), noteably DeTomaso (and the closely
related Qvale
Mangusta)

The Elan body basically holds the occupants and the anciliary equipment. It
certainly
does have any real contribution to the stiffness of the chassis.

Take a look at an Elan with the bodywork off (quite easy to do) and you
will see
a very hefty chassis

In the UK there was quite a business in the 1980's taking Elan +2 models
and
turning them into convetables. It was a doddle to do as no structural mods
were
required at all.

The original Elite used a fibreglass monocoque, and worked well. If is an
idea Lotus
have not really used since, except in the Etna show car from the mid
1980's. On
a couple of cars they have bonded the chassis to the body (early Europa,
possibly
the series 1 Esprit as well, and according to some people the early Elan).
A grp
monocoque can work very well, if you have sufficient space for the deep
chassis
members required. I have a Minari kit car to build (uses an Alfa 33 engine
and
suspension) which uses a grp monocoque body. This has a very strong
chassis,
but then the sill sections are at least 12" deep and 6" wide

Is the MX5 based on the Elan. Possibly stylistically. However engineering
wise
it probably shares more with an Alfa Spider. It is certainly no lightweight
car,
and has more concerns with looking good than going quickly.

All the best

Keith
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