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| Priming the catapult |
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| Ping! The mini is launched |
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The Cat-alysts' diary
Once more the Cat-alysts team had been brought together to defend our reputation and title. We made our way to the yard in our S-Type, to indulge in a little safety training and to inspect what appeared to be a most excellent tool-kit this time! No nasty Banana Splits buggy things either, but proper quad bikes, which even I thought were fun. We also got to grips with oxygen-propane cutting gear – cheaper than all that acetylene, but actually not quite so good.
The yard was in a beautiful setting, surrounded by woodland ... and there, as part of the set wall, was a Renault. But not any old Renault. This was Tim's actual Renault 21 Turbo E527 YKK, with leather seats, which he sold on as a runner in 1992, and here it was, somewhere in Berkshire, done roamin'. Many a mutual friend had enjoyed a ride in that car!
Back to the hotel, where we eventually met up with our expert, Richard. As usual we took him off for a pizza to ensure we could work together, communicate and do business. He hinted at not having had too much preparation time, but hey, we knew it was a two-day build, so we'd have plenty of time to fill in the gaps. After a couple of pre-fight beers, it was off to bed for an early start at the yard.
Build day 1
The farmers looked relaxed and chirpy. I (Garry) felt we could be beaten by no nicer bunch of guys, but of course victory was still our aim.
Robert delivered the words 'a car flinger'. Wow! Big! Hilarious! Pointless! The team jogged off to the wipe-board for a team planning, briefing and 'you what?' session. Our TC did his best to explain. We knew that we were to try for a large cross-bow affair, probably powered by elastic (!), but communication wasn't brilliant.
Want some?
Tim spotted some huge beams and returned for help. Robin of the farmers found them too, and when I returned with Tim there was the makings of a dispute. They were adamant; we were too. But what were the rules? Richard turned up. A fight seemed a not unreal possibility. I am very small. Everyone is, compared to Robin. Oh dear! Eventually Richard decided to settle the matter with picking the hand with the stone in. Their team captain was on hand to make the selection – indeed all of their team were. This left Tim and Shane to scavenge at will, which I could see in the background they were doing, running back and forth with a veritable steel stockholder's inventory. Eventually, Richard revealed the losing hand to Andy, who gamely handed over the huge beams ... and then Richard reveals the other hand was a loser too! He'd dropped the stone behind his back, so Andy couldn't win. I sensed a fix in every sense of the word. Robin, the tall one, made to have a joke fight with me and I caught a knee, by accident, in three of my right ribs. It would be more than three weeks before I could sneeze again without pain – his knee was quite solid!
The upshot was that we chalked our name on the steel and had to leave it where it lay – it was still too heavy to move.
The build went on. Tim had also bagged a very large articulated trailer, which we felt would make an ideal bed for our Mini-launcher ... if only we could move it.
Conceptual struggle
Back at the board, Richard and I struggled to draw and redraw the concept – the pictures weren't going too well but we did know it should be big, with a sledge mounted on two tubular rails, propelled by a giant elastic band. We had no idea how to fix the rubber band at one end, or release it, or even how we would get the tension in the band. Other than that it was all sorted.
Eventually a crane was called to bring the trailer in. There was no way we could move it.
We had some tubes for rails and the material to make a sledge. The sledge had to be as light as possible but yet able to withstand the massive predicted 60mph impact at the point of take off. Shane fabricated it using galvanised scaffold poles and an old zinc-plated frame. It still was heavier than we wanted, at an estimated 100kg, but we hoped it would last for more than one launch.
Tim came back with a lot of rubber bands. We put them aside, knowing we could do that job tomorrow.
Richard seemed ever so keen to elevate the ramp to 20 degrees, whereas the classic thinking was that for maximum distance 45 degrees was optimum (provided that the difference between launch altitude and impact altitude, in this case up to 8 metres, was neglected for all the pedants out there). The discussion did not get me any nearer the reason.
At the end of day one, we seemed to have little to show for our work other than some huge stuff, a trailer, a car we didn't really want and no idea how to release the beast. We retired to consider our position.
Plan B
Back at the hotel, the team reconvened with beer after getting cleaned up. It soon became apparent that sliding four tubes over two rails and having them supporting the weight of a Mini would create too much friction, and would require us to set the gauge between the two rails absolutely perfectly all the way up, and then to keep it that way during the violence of what could be several launches. We came up with a change in plan, something the Cat-alysts try to avoid but had got away with in both the Tunneler and Hydrofoil challenges (see Scrapheap 2001). We decided to have a single guide-rail up the centre, with the same 'C'-section tubes over a tubular rail, but the weight would be supported on wheels running on the very flat bed of the trailer.
Next we turned our attention to understanding how to fix the rubber bands, which with a drawing turned out to be remarkably simple: a couple of shackles fixed to a couple of uprights off the end of the bed-rails.
The next problem was the release mechanism. Why not just pull on a single bolt, which we'd weaken, against an end stop until it snapped. It would all happen in an instance with no elastic relaxation. Voila!
Our attention turned to the tensioning – a pulley arrangement would be difficult and dangerous. We opted to use a tow truck in agreement with the crew's safety concerns, pulling on a chain running under a roller-bearing and up the bed. We'd have to 'bolt' the trailer to the ground to avoid it being lifted into the air by the rearward force.
We had another beer and retired, happy that we now knew exactly what we were doing.
Build day 2
Day 2 kicked off and we briefed our change of plan. With clear direction we were off.
The trolley was put on wheels and the single central rail was fixed to the bed. The tubular rail was fixed to this with perfect alignment.
In mid afternoon, Andy came over to help us with some gas cutting and welding! What a gentleman! So much so that in our hearts we cared not that in the background Robin stole back the steel that only yesterday we were fighting over.
Tim and Richard wound us some rubber bands, which we were promised would launch our Mini into oblivion. Of this we had no doubt – not once did we question this element of our design.
Soon we were cleaning up the bed rails and whizzing 'Sally Rogers' up and down our high-speed runway. Bump stops were added at both ends, using polystyrene as shock absorption at the exit end.
I took to the 'Confession Milkfloat' to reflect on two days of what had turned out to be most satisfactory building. I had to confess, I'd only lost my temper with an immovable piece of steel trailer and a flexible piece of the set – the team had worked brilliantly. Smug mode all round: win or lose, our enemy were fab, we didn't care and intended to win or lose in spectacular style, a damp-squib event being our worst nightmare.
Test day
Our device had been transported to a disused airfield in Surrey. Stitched back together it looked tiny on the airfield; huge next to the support truck – but nowhere near as tall and immense as the opposition's device.
We fixed the bungees, some decking to the trolley, put the trolley on its rails and fixed the whole device to the tarmac. The mono-pod was welded at the correct elevation. We could only manage about 24 degrees.
We selected a bolt that we thought should fail at the right force and tied the device down laterally with a couple of ratchet straps. It was going nowhere – we could only hope the Mini would.
Bump stops of gaffer-taped polystyrene were added, along with a Garry-made effigy of myself, made from a pink sports sock, accidentally dyed by washing with my Cat-alysts T-shirt. I'm sure this sub-consciously represented the desires of some of our less enthusiastic fans!
The truck was hooked up, to be driven by Richard who seemed to know how to make it go OK.
Time to go. The nerves were there – we wanted something big to happen. Andy loaded us a Mini (such a gentleman!) and Richard started to drive away, taking up the slack. We retreated to a safe distance.
Bang!
The Mini crept up the runway to what appeared to be half-way, rolled back down and smashed back into the bottom.
Spectacular
The farmers then put in what we thought would be a huge throw but turned out to be a spectacular failure, the best and most terminal we'd ever seen. The heat was on us to deliver a result.
We added another bungee, with Shane atop a double-decker bus, dangling precariously over the tarmac. We selected a much weaker waisted bolt, sorted the feed through the lower bearing, re-shackled the chain to the truck tractor unit directly and went for another pull.
This time the bolt snapped with a very satisfying crack. The Mini moved off at what appeared to be a very slow pace, then accelerated. The trolley hit the bump stop, creating a shower of polystyrene, the crushed Garry effigy fell to the floor and the Mini left the ramp, landing a satisfying distance away. We knew we'd won but also knew that four more bungees would have given us something more like the performance we'd predicted and hoped for. I'm not sure I'd ever do a bungee jump based on those promised performance figures.
We were sad to have beaten the farmers. I believe their machine could have won, had we not upped the bungee count.
Regardless, the celebrations on both sides lasted well into the early hours, having achieved a result after all!
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