|
Colin and I would do the schemes
on Sunday afternoons at Gothic Cottage then during the week I
would work up the layouts into detail schemes and do some quick
stressing while Colin organized the works and did the suspension
calcs. Weight was one of Colin's phobias and everything was worked
out in detail and just as in an aircraft there was a running
weight and CG estimate. The design would be pretty well settled
before I did the detail drawings and the final stressing calculations.
We were lucky that we clicked
as a design team and seemed to be able to produce a lot better
than either of us could do on our own. Colin was one of the best
designers I ever worked with, always questioning and able to
soak up new ideas like a sponge. Ideas were kicked around and
shot at to see if there were any holes in the argument and this
was applied to other peoples' designs. We would never accept
someone else's design on face value but did our own sums to see
why it clicked, that way we were able to validate our calculations
without having to try it ourselves.
By the time the Eleven design
started we had a very good idea of the design load cases and
had added model testing to our design tools. A 1/5 scale model
chassis made from balsa wood was mounted in a test rig at the
rear axle pick up points and a torque was applied at the front
axle pick up points so we could measure torsional stiffness.
Normal structural calculations with a slide rule would take about
a couple of weeks but this way we could evaluate changes in an
hour or two leaving the long calculations till the design was
settled.
Weight checks were continuous
as Colin needed accurate spring loads to do the suspension calcs.
Here he designed to a plot of oversteer against lateral 'g' which
he reckoned to be the optimum and remarkably, it was right off
the drawing board. That's not strictly correct as on the first
run it did get into a half spin and stuck there so it was back
to the slide rule and a lot of midnight oil. It was about 1 o'clock
and we were both getting bug eyed on about the umpteenth re-calculation
when we found that a bit of short cutting on a long equation
had led to us dropping a 2. New springs were ordered on Monday
and the car handled spot on.
Wheel loadings were always a
problem as tyre load distribution was not well understood so
Colin tried to get hold of a magnesium wheel off a Cooper so
I could work backwards. The foundry wouldn't oblige but gave
him a bootful of cracked Cooper wheels which had been returned
for melting down. We couldn't believe our luck - all the fatigue
testing had been done for us so it didn't take more than a day
or two to come up with the wobbly web wheel.
The Lotus racing team was always
the number one objective but Colin was always looking for a bread
and butter sports car to provide a base income. Unfortunately
small volume production was too expensive. At one time we even
looked at using the 100E Ford Anglia chassis body unit with Lotus
suspension but the breakthrough came when Colin saw the Bond
fiberglass sports car.
Fiberglass would allow small
scale manufacture of a chassis body unit so we started from the
Porsche and worked back to what the weight would have to be to
make a Climax engined car competitive. Next, we worked out a
weight for all the bits other than the chassis, deducted them
from our car weight and arrived at a chassis weight. I went away
to try and put some stress figures to a two seat sports saloon
while Colin went off to work out a shape. Colin came up with
Peter Kirwin-Taylor's Elite shape and I came up with skin thicknesses,
stresses and stiffeners which met our weight target.
That was the start of the Elite
and the end of the original design team. Lotus needed a full
time design team and I had to choose between cars and aircraft.
Cars were fun but cannot compete with aircraft and I was up to
my neck on the Comet and so we parted and that ended my work
with Colin.
|