Thread: Electrathon - A Different Kind of "Hotrod"

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MrWizzard455 - Sorry nobody answered your questions back in June. I missed that posting somehow and apparently Electrathon did too. I can answer your questions, though.

Although there are some that are different, most of the cars run on 24 volts. We are limited to 73 pounds of batteries or two batteries off the approved list, regardless of weight. They must be gel-cell or AGM (sealed lead-acid) batteries. The most common setup right now is a pair of Optima AGM batteries (yellow or red topped) wired in series for a total of 24 volts.

An Electrathon race is a timed event. We run for one hour and the car that completes the most laps in that hour is the winner. We are required to carry at least 180 pounds of "payload" (That is the driver's weight, plus ballast if necessary, to equal a minimum of 180 pounds). So, with a minimum required weight and limited battery power, the challenge is to get the car to run for an entire hour while outrunning the competition.

Cars that utilize the batteries described above run in the "standard" class. That is the most common configuration. If a car owner opts to use NiCad, Lithium, or some other type battery besides the above mentioned gel-cells or AGMs, that puts them in the "advanced battery" class. Although the cars all run on the track together, the different battery classes are not competing with each other. Like a sports-car race, different classes are scored separately.

Went to Tampa to a race at Middleton High School on December 4th. I took my white car and the Optima Yellow-top batteries. A year ago at this same race I embarrassed myself with wheel bearing problems that were my own fault. I thought I was on my way to redemption this time when, about 40 minutes into the first race, I noticed a wobble in my right front wheel. As the race bore on, the wobble got gradually worse. I could see that the hub and brake rotor were running true, so that told me that spokes were breaking, letting the rim warp. With 6 minutes to go I heard a distinct "POP" going into a left-hand turn and the wobble suddenly got dramatically worse. As I passed the flagman I received the black flag and had to exit to the pits. Altogether, I had 6 broken spokes!

I have ordered 12-gauge spokes (stock is 14 gauge) and will re-lace my front wheels before the next race...

Happy new year all,sounds like Jim got the wheel stuff fig'd out.
I sold "Rolling Thunder" today,we'll see if she dose as well or better in other hands? I had a great crew and driver with Rex and Lance,hope new owner can have as much fun as we did.
Dana

Happy New year back at ya, Dana. I just powered up the computer and there was an e-mail from Rodney saying he bought the car. He was here on Saturday the 18th to have some welding and fabrication done on one of his other cars and I told him about the Rolling Thunder car being up for sale. He must have been thinking about ever since.

Sure hate to see your team dissolve; you guys were the class of the field whenever you showed up. Maybe you & Lance should stay in touch with Rodney; he has 3 cars now and can only drive one at a time...

Cool car Jim.

That's the car that Dana "the Bat" just sold. When the Bat and his son (driver) were racing, it won every race it finished. I think it had one DNF due to a flat tire... The car has linkage from the steering to the front suspension so it leans into the turns. Here's another pic of it making a right turn; notice how it is leaning into the corner. Dana can explain it better than me, but it's all about weight transfer to the inside whenever the car is in a corner.

Yup,like any good hot rod,gets the most out of your tires by having balance. In this 3 wheel car it was designed to,and had 33.3% on each of the 3 wheels with driver and bats in it,when ya leaned into the turn 15% was added to inside front wheel and 15% removed from out side front by as you see drivers body mass and center frame rolled over to inside when on the scales. The front wheel/tires would gain camber on the out side and lost camber on the inside of corner as the main body and rear wheel would gain camber as well in turn . This also droped side spoke load a lot.
FOR FULL SIZE RODS;
If ya don't have scales; A trick you can use on you'alls 4 wheel hot rods that can help the bite,find the dead center of rear axle and with a 6in. or so long angle iron point up on top of your jack placed front to back of rear,at the center point jack rear tires off the ground with driver in car=see if both tires clear ground close to same time,if not=the low wheel has too many lbs. adjusted on to it.see if ya can get it close [with in about 2in. at lest] a cross rear and that will also make front good and better braking

I have finished replacing the spokes on the white car's front wheels with the new 12 gauge spokes. They are dramatically beefier than the 14 gauge stock spokes. Next, I'm going to lengthen the steering arms on the spindles to make the car steer easier. I'll take pics of that process and post them here.

OK, ever since my first race in the white car I have been unhappy with the steering. The ratio between the pittman arm length and the steering arms (on the spindles) is such that the car is hard to steer. After two one-hour races on a tight road course my arms are tired and my forearms are sore for a day or so after. When I built the black car I made the steering arms longer so the car is easier to steer. If you have followed this thread, you know that I have been preoccupied with other problems on this car (tires, then wheel bearings, then spokes), some that were of my own ignorance. I chalk all that up to my learning curve... Anyway, it's time to tackle the steering ratio.

I measured the distance (center to center) from the kingpin to the tie rod holes and found it to be 3 5/8 inch. I want to add an inch to that dimension as I did on the black car. I began by marking a line through the center of the tie rod hole (1st pic) and sawing off the ends of the steering arms. I cut pieces of 3/16 x 1 flat stock 1 1/2 inches long and then beveled the ends of all the weld areas (2nd pic) so the welds will penetrate all the way through. Next, I clamped the pieces together and welded both sides (3rd pic). This is the ugly stage.

Next step is grinding and drilling. I first ground all the welds flat with a hard wheel on a pistol grinder. Next I clamped the pieces together with the steering arms back-to-back (1st pic) and ground them to shape. Doing it this way assures that the two pieces are shaped identically. I also drilled the new tie rod bolt hole while they were still clamped together to assure that the holes are in the same place.

After grinding and drilling, I separated the two pieces, dressed them with a soft grinding disc to remove burrs from the edges, then sanded them with 220 grit in preparation for paint (2nd pic). I gave them a fresh coat of Krylon gray primer and finished with Krylon gloss white, the original finish (3rd pic). After a couple hours drying time, I put everything back together (4th pic). I measured the center-to-center hole spread (king pin to tie rod) and found it to be 4 3/4 Inches, an increase of 1 1/8 inch. The car should be appreciably easier to steer now.

hay j.r. can't help but wonder if maybe there is an ackerman angle problem here as we talked earlier if the ackerman is wrong it will push the wheel on the out side of the turn sideways that maybe your spoke problem and hard steer also .there is a good chance I am wrong don't know but I did kick ass in 57 and 58 in go carts at moon cart track and learned some. hope this helps if not just disregard ......ted

Hi Ted. You are probably at least partly correct. There is/ was some Ackerman built into the steering arms, but probably not enough. Now, lengthening the steering arms decreased the angle even further. Although the lack of Ackerman may be a contributing factor, the main crux of the problem was the length ratio between the pittman arm and the steering arms. The pittman arm is 2.875 inches measured from the center of the shaft to the center of the tie rod holes. The old steering arm length was 3.625. The effective ratio then is 1.26:1. By lengthening the steering arms to 4.75, the new ratio is 1.65:1. That doesn't look like much on paper, but it is a 31% difference which makes a big improvement in the way it feels.

Wow, you were really in at the birth of Karting! I drove my first kart race in 1961 (I was 13). My son and I got back into karting for a while in 1995 - 96. I have to say it was a lot more fun in the old days. Now it's just a contest of money and "there ain't enough bang for the buck".

what about using ultra capasitors instead of batteries? they are much lighter and can be charged a million times.I already have the motor and controls. I'll have to give it a try.I'll let you know how it works.

Nissan - Let me know what you find out. Will the charge in a capacitor last for an hour? I thought capacitors discharged very quickly. I'm not sure what class that would put me in...

My son has suggested that I put capacitors in series with the batteries to eliminate power spikes to the batteries when accelerating/ decelerating. I've never pursued the idea because I don't know what I need (size, wattage, amperage) or where to get them.

It would def help to have more ackermam then your using now,I'm sure you know how to lay it out from rear wheel center contact to road point back to king pin and have tierod on that line,but for racing you don't need and should not use full ackerman anyway becuese of slip angle at race speed is higher on out side turn wheel then on inside wheel= you should use at the speeds were going about 1/2 of ackerman<Barlow U of Fla.]
As for capasitors,I beleve that is out by the rules if you check and ask EOA