engineer

tim   .

                                                      


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.   hunkin

                                                         


cartoonist

 

SUPERCYCLE

I have never been sporty. I felt it was a form of abuse being forced to play rugby on Saturday mornings when I was in secondary school. So the extreme competitiveness of professional sport seems bizarre to me. But at times it certainly is comic. I love the ridiculousness of the female Olympic shot putting event with their trouble about the many ‘trans’ contestants. But particularly memorable and entertaining were the 2014 Russian Scochi winter Olympics, when it was proved that the urine samples of all the Russian atheletes had been literally passed through a hole in the wall of the lab and replaced with ‘clean’ samples. It was good that the Olympic committee at the last moment removed their ban on the Russians and allowed them to compete in the Rio Olympics two years later. International harmony is worth a lot more than a bit of cheating in sport. 

I’d had the idea of making an arcade machine on this theme for a while but in March, having spent the winter making youtube videos, I strongly felt the need to make something again, almost anything. The physical making process with all its constant problems absorbs me like nothing else. So I set to work on the sports doping theme with no idea where I was heading. The cycling action is a good mechanical movement for models so seemed a reasonable starting point. I spent a few weeks making cyclists where you pull levers to activate their various leg muscles. This was interesting but a bit mild, particularly because what worked much the best was a single thigh muscle with a flywheel. Pneumatic rams have significant friction, so reducing their number worked best.

   
pneumatic muscle bikes

I continued researching the subject, finding Ken Fogil’s Icarus film particularly good source. This both explained the details of the Sochi scandal very clearly, but also confirmed my impression that in top cycling races that all the contestants are using banned substances to increase their performance to some extent – the key is to stay ahead of the game. There’s a constant stream of new drugs that aren’t yet ‘on the list’, there are some completely legitimate things like living at high altitude (this increases red blood flow) with the added advantage of making random spot tests less likely, and there are legitimate medical reasons for taking some drugs so its impossible to prove doping. I think the Bradley Wiggins doping saga was never so conclusively proved as Lance Armstrong and the Russians. Interestingly the Icarus film also showed what a marginal advantage normal doping provides. You still need to be at the top of your game to have any chance of winning. 

   
small bikes on test

All this detail seemed too complicated for one of my arcade machines. Meanwhile in my workshop I had started trying much smaller model bikes racing round the rim of a real bike wheel. Then my friend Andy Plant visited and he thought the bike wheel should move rather than the little cyclists. At first I didn’t agree but its always fun debating things like this with Andy and gave me the idea of using differential gears to move both the cyclists and the scenery.

 
First mechanical doping test

Near the beginning of the Covid lockdown I had explored a good wormhole. Starting from problems with the capstans on my Pirate Practice machine I became fascinated by Vannevar Bush and his work on mechanical computing in the 1930s. It was incredibly influencial – all the WW2 bombsight ‘computers’ for ships and aircraft were mechanical, based on his research. Differential gears were an element of this that was used to add and subtract. Used in opposite to how they are used in cars, the inputs go in through the two ‘rear wheels’, with the propshaft output the average speed of the two inputs. Then if the rotation of one ‘input’ is reversed, the propshaft output is the difference between the two inputs.

   
differential gear test

Finding the right differential gearboxes was tricky. There are tiny ones made for model cars, or large ones made for golf buggies, but very few in between. I eventually used a couple of golf buggy ones with 25mm shafts just because I already had them. The finished mechanism, complete with ‘cheating’ motors looked impressive. Later I was amazed and delighted to find that ‘mechanical doping’, adding hidden batteries and motors within the frames of mountain bikes, is an actual phenomena.

   
first race test

I wanted the doping to be secret. So you get told what to do by listening to advice from your coach through an intercom. My first idea for secretly activating the doping during the race was to pull the crank wheel towards you. I got this to work, but it somehow just didn’t feel like doping. So then I started playing with hidden foot switches and at some point thought of making them vibrate. This wasn’t right but led to trying an offset motor that wobbled your foot a bit. Finally for some reason this felt suitably medical, I could imagine the drugs being pumped into my foot. The first version was impractical because it would have got clogged with sand when on the pier. I went through 6 versions before settling on the final one. Though later I decided the effect is too mild to be noticed in the heat of playing the game so I’ll probably rebuild it yet again.

   
secret cheat switches

   
foot switches

The problem was that I had greatly underestimated the friction of differentials and other gears. Though still easy to turn, it meant the cheat motors needed a lot of power. I was shocked to find the original battery drill motors with a 4:1 reduction were drawing 9 amps each. I’m always nervous about large currents like this – smaller currents which can’t overheat wires etc. I tried larger mobility scooter motors instead. Ungeared these still drew almost as much current, but geared down 3:1 they now take a modest 2.5 amps.

I managed to get the machine in a playable state for the summer half term, ready for my grandchildren to try it out. It’s been very useful with many machines but particularly with this one. Jessie pointed out the obvious flaw in the game – “what’s to stop players just activating the cheat motor for the entire game?” but after a short pause added “its obvious, they will overdose and stop completely”. This was a proper Eureka moment. The game could be more like the real world, with the skill in judging how much dope you dare do without overdosing. Then Ellie, my daughter, suggested dividing the race into stages like the Tour De France so you can gradually perfect the optimum doping technique. 

   
Sam and Jessie test run

Nearing the end of making any machine I always have a crisis of confidence, maybe this is getting worse as I get older and have more experience of what doesn’t work. With this machine, playing it somehow just didn’t feel instinctive or satisfying enough. There’s a lot more mechanical complexity than most of the other machines, so only at the last moment did I have to address some wierd issues that had never occurred to me. Its actually essential to balance the relative amounts of friction in each part of the mechanism to get it to work well. 

While this final period of making a machine is definitely stressful its also exciting and gets my brain going like nothing else. It reinforces my bafflement of the fine art world with their emphasis on ‘concept’ rather than detail. The curators and critics just don’t have the technical knowledge to engage with any of it. But of course it suits me perfectly to be ignored by the lot of them. I get enough personal feedback to know people enjoy what I make. 

As the machine got closer to moving to the pier, my main concern became simply to get the Brightsign media players to change tracks quickly and reliably. The game becomes so much less intuitive if they don’t reliably keep up. I found the players are a lot less responsive if tracks includes sound tracks, so I added separate sound effects to mix with the mute brightsign tracks output. Also downsizing the video files to 720p helped a lot, as it does with so often.Over the years I’ve found its better not to announce a new machine at first..its more useful to watch how people react without any publicity and less embarrassing when it inevitably goes wrong with teething problems. This one worked better than many. Kids enjoyed manically cranking the handles and adults got the jokes. Everyone seemed to start by turning the cranks in the wrong direction – it will be a pig of a job to reverse them but I’ll bring the machine home in the winter to do it. I had underestimated the enthusiasm with which people would turn the cranks, the chain came off and then a bearing seized – more reasons to bring it home!

 

 

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