Thread: Electrathon - A Different Kind of "Hotrod"

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Congratulation on your good showing. Is this the start of a dynasty for Robinson Racing.

Last week I chopped up V1 (version 1) in order to start fresh on V2 for the new year. I thought I would share a couple of lessons that might be useful for builders without a lot of experience.

1. Build a decent platform. This platform will be the base for all measurements and fastening jigs. A two foot by eight foot sheet of ½ inch plywood on two sawhorses was not enough. For this iteration I fastened the sheet of plywood to eight foot 2X4s running beneath the plywood like floor joists. This provides a nice solid platform which does not sag that is still light enough to move out of the way if the space is needed.

2. Screw a eight foot measuring tape directly to the middle of the plywood platform. The edge of the tape provides a reliable mid-line and the tape provide a constant frame of reference for measurements along the length.

3. Prepare a bunch of layout blocks. In order to hold things in place for welding you will need fixtures to hold the tubing in place. Rather than scrounge up a suitable piece of scrap while you are thinking about the joint, it is handy to have a bunch of pre-drilled blocks on hand. You will already have enough on your mind when doing the lay out.

4. Set a tolerance. While working is it hard to know what is good enough. Experience must help a lot, but until I have that experience I decide that everything must be within 1/16 of an inch when fitting most parts. Steering and driveline must be a good deal more exact This seems reasonable without being too exacting.

5. Set a margin of error of joint fits. After a bit of experimentation I found that having no more than .035 of an inch gap on joints makes for pretty decent welds for someone of my experience level. Anything bigger and I tended to blowholes

I look forward to hearing more about your season!

Thanks for all the compliments, everyone. My son's win eased some of the pain I was feeling after the event, but I was still sore for two days after! I'm probably getting too old for this.., but it's just so darn much fun! Next race is January 17 at Wharton High School. I don't particularly like the track layout, but at least it's tolerably smooth.

David - If you look back at the beginning of this thread, I used a 2' x 8' piece of 1/2" plywood to make my "frame jig" platform. At the time I had it clamped to two work tables in the school shop. That kept it flat and level, but I later put 1" x 4" (on edge) framing under its perimeter and then added "wings" on either side to locate the side pods. I also built a fixture to hold the rear fork in place instead of using the plumb bob and measuring tape. Another fixture holds the kingpin bosses at the correct angle for welding and others hold the rear hoop and roll bars at their correct heights. I cut a stack of 2" x 4" blocks from 3/4" plywood to use for holding the tubing in place on the platform (plus I clamp the bottom rails down) and attached them with drywall screws so they can be moved if necessary. I'm still using the jig and all the fixtures. It's showing a little wear after having built 9 frames, but is still flat and accurate. I bend, cut, fit, and tack all the pieces together. Then I weld everything that I can reach easily. After that I take the frame off the jig and roll it over and over to weld all the otherwise difficult areas.

I just have a center line drawn on my jig, but attaching the measuring tape along the center is a good idea. Speaking of measuring tapes, if you need to measure around corners or a piece that is already bent, get a fabric tape measure from the sewing department at Walmart or a fabric store. I've kept a couple in my shop for years.

Good news, folks. The January 17 race is now history and it was another victory! Saturday's race course was set up as an oval on the Driver Education field at Wharton High School in northern Tampa. It actually was a similar course to the one we ran last month at Middleton, but this one was not a "boneshaker" like that one.

My son wasn't available, so I got an old friend of mine (and former go-kart champion), Jerry Bristow, to drive the #13 car. The cars were lined up according to car numbers, so Rodney Schreck #4 from Miami was on the pole, Bristow in the #13 was outside front row, and my #94 was deep in the field. It was a pretty uneventful race and at the end Schreck finished first, Bristow was second, and I was third. All three of us turned 126 laps and there was a mere 6 seconds from first to third.

In the second race the starting field was inverted, so I started outside second row. Schreck and Bristow were at the tail of the field. At the start, the two cars in the front row separated coming off turn two, so I shot between them to take the lead. Down the backstretch Bristow managed to pass the entire field to take second behind me. He matched me move-for-move through traffic for about the first two-thirds of the race until Schreck caught and passed him. At 20 minutes to go I dialed up the throttle, as usual. I seemed to have some uncanny good luck with traffic at some points while Schreck and Bristow were struggling to get through it. That worked to my advantage as, late in the race, I caught and passed Bristow to put him a lap down. I had Schreck in my sights and almost caught him, but then the traffic started hindering me and helping him. We finished that way. Schreck and I had turned 128 laps; I had about 3/4 of a lap on him and a full lap on Bristow.

In Electrathon, the total laps for the day is what matters and when the officials totaled the laps Schreck and I both had 254. The tie breaker then is total time; Schreck logged his laps in 2 hours and 31 seconds, but I did mine in 2 hours and 29 seconds. I won by a mere 2 seconds! It is the closest finish in Florida Electrathon history.

Aside from cars that I built finishing 1, 2, 3 in the Open Class, the car that I built in the first part of this thread also finished second in the High School division. The Tampa Bay points keeper commented that my cars have become the "class of the field" and they are "fast and reliable"...

I've been following this thread with a great deal of interest; it's good stuff and I've enjoyed reading it.
And to see you get results and comments like that...well; give yourself a well deserved pat on the back that man!
You've earned it.

Way to Go Jim. Congrats on the victories! And way to go on your designs too.

Times 10 on the congrats! A 1,2,3 finish with your cars is certainly a great achievement and you should be very proud!

I know we here in the club are proud to see the results you've been getting too!

So like all racing.. What's next?!?!?

Thank you all for the compliments. Yes, it's nice when your efforts finally start paying off. I got involved in this sport back in 2002 when my students and I began construction on our first car. At first we had trouble just finishing a race and it didn't matter if I had students driving or if I was doing it myself. When we finally got one of our three cars to run the full hour in a race it was usually at the tail of the field. After a few years of tinkering we got so we could finish in the top 5, then the top 3. I retired in 2010 just as the race schedule began to expand from 3 races a year to 7. Finally, in 2011, with no more students to mentor, more races to run, and intensified focus on what I was doing, the cars I build became contenders for a win at every event. That gives me a good feeling.

Formula E? I look for that type of racing to expand rapidly. It may need a few tweaks to really gain fan acceptance, but it's cool. As for me, I think I'm a bit old for any teams to be interested in me.

What's next? More of the same for now; I'm still having fun. I'm rapidly approaching the day when I'll probably give up this sport, though, and leave it to the younger folks (I'll soon be 67). I still have my coupe and roadster to keep me busy.

Originally Posted by J. Robinson

Thank you all for the compliments. What's next? More of the same for now; I'm still having fun. I'm rapidly approaching the day when I'll probably give up this sport, though, and leave it to the younger folks (I'll soon be 67). I still have my coupe and roadster to keep me busy.

It's great that you're enjoying it.. kinda reminds me of a song from the late 70's / early 80's about doing it 'til you're satified..


Speaking of the coupe & roadster.. what's the latest?

Did you ever find out what caused the flats?

34-40 - That's pretty good; "Do it till you're satisfied". The song that runs through my head sometimes when I'm passing those high school kids is Toby Keith singing "I ain't as good as I once was, but I'm as good once as I ever was." I guess it's especially true when we old fat guys beat the kids by 15 or more laps.

As for the coupe and roadster: I have a 15 gallon aluminum fuel cell that I'm going to put in the coupe. It fits differently than the old 10 gallon Geo Tracker tank so the increased capacity doesn't take away any more trunk space, but my range will increase by 50%. The roadster will just get driven... a lot.

Thanks for the reply Jim. The fuel tank sounds like a great idea, especially the increase in drive time / range! More time for doing "it"!! LOL..

I haven't updated in a while, but we've been having a pretty good season. In February we raced at USF Tampa during the annual Engineering Expo and, once again, cars that I built finished 1 - 2 - 3. This time it was Rodney Schreck from Miami who took top honors. Jerry Bristow, driving my #13 car, took second. I dropped out late in the first race with a blown rear tire, but finished the second race with no problems. I logged enough laps in my total for the day to capture 3rd place.

In March we raced at Tampa Bay Technical High School. Late in the first race, Rodney and I got into a "tooth and nail" battle for first place, swapping the lead back and forth for several laps. I finally managed to outrun him off the last turn of the last lap and hold onto the lead, beating him to the finish line by .8 second. My son, driving the #13 car was a close third about 6 seconds back. In the second race, Rodney was involved in a mishap caused by a rookie driver and lost 4 laps. Later, with about 8 minutes left in the race my son's rear tire went flat, forcing him to retire while leading. When the day was over I won, Rodney was second and Jim Jr was third. Once again, cars I built finished 1 - 2 - 3 on the day's total laps. Post-race inspection revealed that my son's rear tire was worn completely through the casing causing it to blow. My rear tire was showing cord all the way around; if the race had lasted two more laps I likely wouldn't have made it!

Is it just me?? Or. does it sound like you folks have a lot of trouble with tires? Seems like we read about tire issues quite a bit. Or is it that the tires are just being overloaded in this application?

Just curious.. and once again, congrats on all the successes!!!

Congrats Jim. Very impressive engineering and strategy here!.

34-40 - Yes, we do have occasional problems with tires. We are using bicycle tires in a manner which they really aren't designed for. On a 20-inch bicycle, two tires are carrying the weight of a bicycle (usually less than 30 pounds) and a rider (usually less than 160 pounds). The tires and wheels have the added advantage that they are leaned or tilted into corners at a rate that keeps the tread at it's best angle for traction and the spokes in line with the load place upon them while they corner at speeds of 5 to 10 mph. We take those same tires and wheels, load 400+ pounds on three of them, hold them at a fixed angle, and attack tight corners at 20 to 35 mph. If the surface is the least bit abrasive, it will just grind the tread right off the tires (and sometimes break a few spokes) in the course of the two 1-hour races at a typical event.

Having said all that, though, I must now admit that we started the day on used tires! The rear tires on my two cars had been used at the last race (USF Tampa in Feb.). I thought they had enough tread left to go the distance this time, but I obviously was wrong. I simply misjudged how abrasive this track's surface was. Had I not made that mistake, my son would have beat me by over a full lap.

Thank you both for the compliments. Looks like I'll probably miss the April race because of an obligation elsewhere. The last race of the season is May 2nd in Cocoa, FL. I won that one the last time we ran there; I'll be trying for a repeat... with all new tires on both cars!