Week three. The challenge is to construct a human
bowling ball. The device can be motor-powered for some distance, but must
then free-wheel and cannon into some very large skittles.
This week's teams are the Up 'n' Atoms - Ali Day,
David McFarlane, and Jimmy Ridewood, who work at the CERN labs in Geneva,
and are playing in royal blue. Graham Bridges is their expert. Their outline
plan is to put a small car in a
single large metal frame - it's about 85% of a
roll cage - and put on the brakes so suddenly that the whole thing rolls
forward when they put on the brakes. The really clever bit is that they'll
drop down the last bit of the cage when they hit the brakes.
The RENE Rebels - Mandy Foster, Claire Riding,
and Gina Smith - work in the Royal Navy Engineering division. Their expert
is Pete Smith, and they're playing in bright yellow. Their plan is to mount
a moped between two large wheels; the moped will then lift up, and spin
the rider round in the frame. Key to this has to be a spring-loaded system
to raise up the moped at the right moment.
To make their big wheels, the Rebels weld sheet
steel to a frame, then cut it down to size. The wheels must, of course,
be the same size, otherwise the contraption would veer madly off in all
directions. Early in the build, that
would be their main challenge.
The Atoms haven't been able to find any wheel-shaped
steel. They have found plenty of straight steel, which they can notch,
bend, curve, and construct their two big wheels. They also need to shrink
their car, otherwise it'll stick out the ends. Solution? Cut the middle
out of the car.
In time, the Rebels find there isn't enough sheet
steel, so replace that idea with spokes - effectively, they're making two
large bicycle wheels, with a moped joining them in the middle.
As build day progresses, attention turns from the
wheels to the way they'll take the motor off the ground. The Atoms develop
a pivot system, one that should complete by force of gravity when the brakes
go on. The Rebels have a
spring-loaded hinge, something it looks like they'll
have to work manually.
For the Atoms, it's disaster, as the large wheels
are different shapes. Back to the old welding board. Both teams complete
their outline wheels with an hour to go, but the Rebels have their A-frame
spring contraption, some stabilising cross-struts, and steel-plate reinforcement
for the wheels yet to fit; the Atoms have their wheel-completing catch
to finish, and a counterweight to install to start the forward roll on
their big, heavy machine.
Thence to the actual bowling. The teams have a
100 metre run-up under petrol power, but must then cut their engines and
roll 50m to the skittles - made of three oil cans piled up and wrapped
in cushioning.
The Rebels go first, make a very good roll down
the course, cut the engine - and splutter to a stop. The hinge didn't lift,
probably because their driver didn't let go of the handlebars. The Atoms
go hell-for-leather, hit the brakes,
topple forward - and topple back. Not enough forward
momentum.
Run two for the Rebels, and there's a lot of speed,
and a couple of skittles go over. But the wheel wasn't turning, the hinge
hadn't worked, it was all under motor power, so no score. Second shot for
the Atoms has the speed to topple the wheel over, but then the contraption
comes back, rocking to a halt.
Everything hinges (and weights) on the third run.
The Rebels have brought in a rope to activate the hinge, the wheels come
off the ground, but there's not enough forward momentum to send the wheel
into a roll, and it skids to a halt
just before the front pin. The Atoms have added
some water tanks containing more ballast to their ball, and that extra
weight brought the wheel to the skittles, and no less than seven fell.
The Up 'n' Atoms are this week's winners.
*Ali Day emailed me and provides this
link to a site about their experience