HIGHER EDUCATION
On the ground at Battle Mountain
Things did not go quite to plan once the races started. Early
indications were mostly positive; it wasn’t until after riding the
2.5-mile course that the major problem emerged
Continued from previous page
The drivetrain of the Velociraptor
was one of the areas that the team had
reengineered in the year-long run-up to
the race, including supporting the steering
column at both ends and changing the
bearing surfaces on the left-hand end
of the steering axle to travel on rails.
Although that stiffened the steering, it
also highlighted the major signi cance
of the effect of the offset steering. The
team had known that it would affect the
bicycle’s handling; bumps in the road are
trying to push the wheel backwards and
turn the bike to left, forcing rider Russell
Bridge to steer it back to centre. Barney
Townsend, the South Bank University
project lead, explains: “On the road tests
that we had done in the UK, it hadn’t
seemed a problem; it felt perfectly stable.
That said, in the UK the only tracks that
we had access to were a mile or a bit
longer, they don’t give us the ability to get
it up past 40mph.
“In Nevada, the bike ran the 2.5-mile
course happily enough, but with a bit of
weave. And then we got on the ve-mile
course, and it was getting up to well the
other side of 50mph – 55, 56mph – and
he was really struggling to control that
steering.” Eventually he crashed, at
greater than 50mph. Fortunately, Bridge
was ne; the new heavy composite
carbon roll cage protected him, and the
integrity of the vehicle. Had the same
thing happened with the previous design,
Bridge could have been injured or even
killed from road abrasion.
Although the crash didn’t threaten
Bridge, it did threaten the team’s medal
hopes. Continues Townsend: “We did
some head scratching. We knew we
could tune it a bit, and keep racing; we
could shorten the steering arm to make it
less sensitive, and things like that. But,
ultimately, the problem was exacerbated
by speed, so it would only get worse, and
if we managed to tweak a few more miles
an hour out of it, he would only end up
crashing at a higher speed. Ethically, we
thought the best thing was to have a big
rethink.”
The team knew it would be impossible
to rig up rear-wheel steering; that is said
to pose big problems with stability for any
bicycles, but particularly recumbents that
feature a lower centre of gravity. And it
also knew that, since the crash happened
early in the competition, it had a (little)
time to try a x.
CAR PARK ENGINEERING
“We had a team of engineers here, and
a reasonable toolkit, albeit our workshop
is the motel carpark,” reasons the
Last evening run
“In the space of three quite intense days,
we transformed that bike from a front-axle
steered, front-wheel driven, rear-braked
bicycle, to a rear-wheel-driven, front-fork
steered, front-axle braked bicycle. It was
quite a signi cant rebuild of all of the
mechanical components.”
The transmission unit and front wheel
were housed in between two side panels
of carbon and then an upright front
column that held the front bottom bracket
and chain-ring axle and the cranks. The
team recon gured the frame, cutting
the side panels in half and rotating one
upward, and built a new upright column
sitting between the wheel and the rider,
and mounted in that a pair of bike forks
pirated from a new bicycle bought from
a shop an hour down the road. The main
chainring was kept in the same place,
offset far enough from the front wheel to
enable a degree of steering. It drove the
8mm machine drive chain, lengthened
with spares, running all the way
shell and
engineering lecturer.
Arrival at fi nish line on fi nal evening after a
successful fi ve-mile race on new bike
The punishment infl icted by a
50mph crash on the composite shell
Figuring out the chainline in
the new confi guration
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