US Lotus Elise Chassis
Elise Chassis Basics
The key to the Elise's featherweight and its immense rigidity
is its extruded aluminum chassis. The Elise chassis is an aluminum
tub that creates a backbone for all of the other pieces of the
car to be hung. The Elise tub chassis is made by Hydro Aluminium
(automotive group) a company that makes many aluminum products
for high-end auto manufacturers.
Twenty-six pieces of extruded aluminum are used to create
the Elise chassis. The extruded aluminum pieces are glued and
"riveted" together creating a layer of material that
is both lightweight and remarkably stiff. The rivets used in
this process are used to hold the pieces together during curing
and also give the chassis some resistance to "peeling"
during an accident.
Elise Chassis Weight and Rigidity
The Elise chassis weighs approximately 160 pounds a weight
savings of over 50% of a conventional steel welded chassis. The
S2 Elise differs from the original S1 by reducing the height
of the doorsill side rails. The reduction in doorsill height
made entry and exit in the S2 a much easier feat without dramatically
adversely affecting chassis rigidity. To reduce the doorsill
height, the side of the chassis was cut down slightly and then
re-enforced with bonded and interlocked pieces. The result was
a chassis that a slight reduction in bending strength but an
improvement (approx. 7%) in torsional rigidity. The added bonded
material also resulted in a slight weight increase of about 9
lbs over the original S1 chassis.
The result of this process is a very stiff chassis that
does not need a roof to maintain its rigidity. A "hard top"
can be fitted to the Elise but only serves a purpose of keeping
the water out not enhancing the chassis rigidity.
Elise Safety
The Elise chassis is also very safe in an accident. The strong
chassis and progressively collapsing front crumple zones are
quite effective. What is not generally known, is that not only
does Lotus design and develop suspensions and engines for other
manufacturers; it also does secondary safety work as well. In
fact, Lotus has designed the crash structure for the Aston Martin
Vanquish.
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