The test chassis was exactly that: a rolling welded aluminum and carbon-fibre frame used to test motors and controllers and other parts. We had the run of one of the university stadium’s grounds at night, so the test chassis needed headlamps and a safety beacon. I went to a local parts store, picked up a couple of rectangular sealed beams, someone welded up some aluminum frames to cage them in ,and they got lashed to the front of the chassis. I made up a safety beacon out of a halogen bulb, a flasher, and a few bits of wire. Round and round the stadium the test chassis went, through the night brightly.
The car—the actual solar car—posed more and bigger challenges than the test chassis. We couldn’t just throw parts on it; we had tight packaging and mass constraints, race regulations to comply with, and conflicting needs for various aspects of the thing. It was very much like conceiving and realising a production vehicle, which was sort of the point.
But despite all those constraints and conflicts and regulations, there was still often more than one way to do whatever was at hand. For example: turn blinkers. The race was to be run on public roadways, so the car had to have stop lights as well as front and rear turn signals. The actual light units, front and rear, were provided on a sponsorship basis by some sketchy outfit called of Daniel Stern Lighting. The front ones were VW turn signal repeaters, while the rears were wide, low-profile central stop lights intended for incorporation into spoilers; all made by Hella. Okeh, but there was some intra-team kerfuffle about how to control them. A few of the team members debated whether to use an oscillator or a flip-flop or some other kind of circuit I don’t remember with a sonolert or other annunciator and a switching logic board to control and indicate the turn signals. They were worried about having to find a place for four lights on the razor-thin rear of the car, which Aero/Body would not agree to unless absolutely every other option had been studied and rejected. So they were designing ever-more-complex circuits to have the brake lights double as turn blinkers.
I excused myself and drove to the nearby auto parts store, where I fetched a particular 2-pin turn signal flasher for $7. Drove back and tossed it on the table, where it garnered some blinks and stares of incomprehension. I picked up the dry marker and drew a simple circuit on the whiteboard: the lamps’ feed wires were to be hot full-time, and left and right A/B toggle switches would select between two ground paths: one via the stop light switch on the brake pedal (only for the rears), and the other via the turn signal flasher (fronts and rears). There was a fair amount of doubt, but they wired it up and the system worked fine. Even had a nice, loud click audible to the driver. How many days and dollars would’ve been taken up designing and debugging a complicated circuit and bypass arrangement to do exactly the same thing? I guess more than the 45 minutes and $7.
All the other teams used pickup trucks or Suburbans to pull Haulmark or Wells-Cargo type trailers just big enough for their cars, but we were the University of Michigan, so ours was a semi-truck type, a 48-foot box on wheels. It had exterior speakers wired up so we could play the UM football fight song loud enough for all the rest of the teams to hear, which I thought was unseemly and tacky and nobody cared to hear my thoughts on the matter.
We built a full machine shop into it, with a special compartment for the car in the aft lower deck. We built a powered liftgate large enough to accommodate the entire car, then lift it up to be rolled into its berth, then fold up vertically to form the rearmost wall of the trailer. For roadside safety, the shop door was on the starboard side of the trailer box. The trailer and its contents were powered by a trio of generators with Briggs & Stratton 2-cylinder engines, all in an underslung housing made out of diamondplate and angle iron.
The Chief Engineer used threaded black iron pipe to create a rather nice six-into-three-into-one exhaust system for the generators, with the single 2″ common pipe passing through the forward wall of the housing. But the niceness didn’t survive the trip through the wall—to the threaded end of the 2″ iron pipe he clamped a 90° automotive exhaust elbow, with the other end pointed starboard. To this he clamped an automotive muffler. The tailspout was a plain straight pipe about 6″ long, ending about a foot away from the shop door.
Eventually, once we were on the road and in the race, machine shop users started complaining of persistent headaches when using the shop. It hadn’t shown up as a problem before, because why use the trailer shop when the much bigger homebase shop was available? I got in one of the vans, drove to an auto parts store, and picked up some elbows and lengths of plain exhaust pipe, some hangers, and a downturn tailspout. Back on site, I removed the straight tailspout and rotated the muffler-and-elbow counterclockwise about the headpipe through an angle of 135° so the muffler outlet was looking down at about 45° on the port side. I ran straight pipe down to just inside the lower corner of the box, then a 90° elbow exiting rearward, then a length of pipe running rearward, then a 45° elbow drafting outward from the lower corner of the box, and capped it off with the downturn tailspout, well away from any air access point to the inside of the trailer. The machine shop got a lot quieter and the headaches went away.
That wasn’t my only involvement with the trailer, either. It needed an exterior lighting system that would meet both US and Australian regulations, as we really had our eyes on that Australian race, and we really had the means to ship the entire freakin’ 48-foot trailer halfway round the globe. So I went on a great big shopping spree, extra-fun because it wasn’t my money I was spending for thirty-three part numbers and a hundred and thirty-eight items. The new rear lights went on the outside surface of the liftgate.
There was some astonishment one night when I fetched a tube of RTV silicone and used it to seal something or other back there—maybe a wire access chamber or something. I certainly wasn’t the only one on the team who knew about RTV silicone, but I was the only one in that group that night: look here, he’s got some kind of miracle: squeezable goop in a tube that turns into actual rubber if it’s left alone awhile! This is not me claiming to be the only smarty on a team of idjits; I wasn’t and they weren’t. But it might’ve been good if there had been some attempt at a formal, organised exchange of knowledge rather than its ad hoc distribution, too thick in some places and way too thin elsewhere. Keep the RTV in mind; we’ll be back to it in a bit.