The Red Bull Billy Cart Challenge

Red Bull Billy Cart 2015 / James Bond – Lotus Seven

By John Barram

It all started a couple of months ago when our son Richard requested my involvement if he was lucky enough to be accepted into the first Australian Red Bull Billy Cart challenge. Now Red Bull, being Red Bull, don’t have an ordinary soapbox race. They have a comedy event where a team of four is to build something from scratch, do an amusing 30 sec skit related to their “theme”, then run the billy cart down the course, through slaloms, over jumps and even down stairs. So I watched the YouTube clips, most of which involved riding something like a giant hamburger down the track until it fell apart over the jump. Hmmm.

So my response was that if I/we were going to make the effort to build something, I wanted to build a scale model Lotus Seven which would not fall apart during the event and just might have a use with my little grandsons who are fast approaching the age where they could enjoy such a thing, possibly with a motor!

There were over 500 applications and Richard was one of the 60 chosen. His theme was “The James Bond Wedding Car” so their skit involved a couple of his big, hairy mates dressed up as the bride – Miss Moneypenny – and the other as a Bond Girl in a bright orange bikini interrupting the wedding and then Bond “escaping” down the track in the Lotus Seven.

So we had about six weeks for the build. We soon established 60% was the smallest we could go, so we got some steel and started cutting and welding and in three days had a rough frame. Meanwhile Richard had been scouting for appropriate wheels and had come up with mini moto-cross wheels, complete with brakes. The people at the Big Kart Track were keen to help and came up with front upright/axle/steering arm assemblies, plus a steering column and a seat from their karts. We went with a simple swing arm front suspension with spring/shock assemblies from a little quad bike.

The back axle we welded rigidly to the frame in the name of simplicity and ruggedness. Richard would need padding on his seat! By this time my brother David had got involved, and the pace quickened.

We could see from the previous races that Red Bull was setting tougher and tougher courses, with lots of the racers breaking over the jumps. So as soon as we had it mechanically complete it was test time. We easily achieved 48KPH on the sort of slope expected. It steered and it braked. Then for the jump. The first at about 30kph over 25cm was a breeze. So we went to 50cm with a steeper approach. Richard and cart flew through the air rotating steadily forward until he landed nose down at 45%, crunching the frame on to the roadway as the suspension bottomed out. But nothing broke and nothing bent. So we rearranged things to double the front spring rates and left it at that. It was time to get serious on the body.

Flat aluminium panels are no challenge to people who have been around Clubman race cars as long as David and I have, so these were soon sorted. We have access to a set of rollers so the bonnet and rear corners soon followed. But the most complex shapes on a Seven are the mudguards and nose.

I had a 45 year old pair of Seven front guard moulds which were no longer serviceable so I was able to cut the mould down to about 60% length in a way that gave a reasonable approximation of the full thing. Done. They just needed a lot of filling and finishing. In the “old race car parts” pile we came up with a pair of Clubman front guards which had enough flex in them to pull them in to the tighter radius required. A bit of trimming here and there and we had rear guards. But we could see no real shortcuts for the nose. So I made up a wooden frame and glued on surfboard foam. I then took to it with knives and sanding equipment. By the end of the day I had the shape of a nose, at least good enough for this exercise, so it went off to a mate for coating in fibreglass.

The fibreglass panels were painted, we sorted the brakes, checked the wheel-alignment, fitted head lights and a “windscreen” and with a few days to spare were ready to roll. Then off to Sydney with it in the back of Richard’s Prado like it had been built to fit. Pure fluke!

There were plenty of carts with an Australian theme and plenty of laughs. There was a Harbour Bridge, an Opera House, a meat pie, a Chiko roll, a thong, two shrimps on a barbie, etc. There was a beautifully built little Delorean and Derek Dean’s boys were there with a Ghostbusters entry.

The track, however, was mild compared to the more recent ones used by Red Bull. Most carts built up very little speed on the mostly gentle slope and the 20cm jump held few fears. It was a bit of an anti-climax for us. In speed our cart was about 12th out of the 57 runners.

The winner was the Harbour Bridge, iconic, beautifully built and one of the quickest carts there. It was a lot of work but a lot of fun. Now to fit it out for the grandsons!