Thread: Electrathon - A Different Kind of "Hotrod"

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Thanks, Resto. And that's a very good question that maybe I should have addressed already. It is purely a matter of personal preference. The reason I don't put lateral bracing on the front axle is because, if it hits something hard enough to cause damage, I would rather just bend the axle tube than transfer the damage to the frame.

In the pic below you can see the front axle in this car only has vertical bracing. I was cut off going into a corner one time and simultaneously tangled with the other car and the curb. The left end of the axle was pushed back two inches, but the wheel was undamaged and I was still able to finish. Between the day's events, I was able to straighten the axle and went on to win the second event of the day! Had the axle been laterally braced, it could have caused damage to the frame that might have sidelined me for the rest of the day. As I said, it's a matter of personal preference, but Electrathon usually isn't as "rough and tumble" as Karts (I've raced those, too).

Reasoning understood. Just wondered.

Your build is going great!
To cut down steering frictoin in Kingpin bose on mine,i may of over did it using small PCV as a inter bushing with graffight and some small flat bearings at the base. But I was going for a power steering feel,seems to work well.
I did use ackerman for steering arm lay out,if thats helping any one.

OK, I was gone for a week on Spring Break. I spent the entire week painting the outside of my house... Anyway, we're back at school now and I can continue.

Having built the front axle, the next logical step is to fabricate some spindles. For the knuckles I used 3/16" x 1 1/4" flat steel. The first piece I fabricated is the steering arms. These pieces also form the top piece of the spindle knuckle. No rocket science here, I merely drilled the appropriate holes and then cut & ground the pieces to the shape I wanted. The hole for the tie rod is 1/4", the hole for the king pin is 3/8", and the other holes are 1/2" and are just for reducing weight. Notice I bolted the pieces together for grinding. That way the two pieces are identical. The other pieces are pretty self explanatory. The long piece has a 1/2" hole near the bottom where the spindle shaft (a 1/2" x 5" bolt) will be welded later. The little piece is just the bottom piece of the knuckle.

To assemble the spindles, I cut a scrap piece of 2" x 2" lumber on the miter saw. I was careful to make sure the saw was squared so it would cut nice square ends. I then cut the wood 1/16" longer than the kingpin bosses on the axle (kingpin bosses are 3 3/4"; I cut the wood piece 3 13/16"). I bored a 3/8" hole through the wood so I could bolt the knuckle pieces in place and then positioned and secured the outer piece with a clamp. After welding the outside, I removed the knuckle assembly from the wood and welded the inside. I simply repeated the process (using the same wood block) for the other spindle knuckle being careful to arrange the pieces so it would make the opposite side.

jr I was wondering if ackerman angle matters on 3 wheel cars ....ted

Yes, Ted, the Ackerman principle is the same as on a 4-wheel vehicle. As you will see when this car is finished, there is some Ackerman angle built into this setup. It isn't as critical here as it would be on a heavier vehicle that uses wider tires, but since friction and rolling resistance are definite considerations in Electrathon competition, I try to build some Ackerman into my front ends.

Hay we're all big shots we made April 09 "AutoWeek" mag,heres the page.
I'll add a small thing about ackerman; On a race car or any car that's driven hard,the front tires have a slip angle to each wheel that is not the same on each side becuase of def load,under hard driving to the real way that there pointed,this varys depenning on speed and is why ackerman can be a bit less then perfect to design as layed out in book[that is great for normel driving].

Cool! We need all the publicity we can get... I wonder if there will be any coverage on the event at Pensacola (Five Flags Speedway yesterday). Ten cars showed up; Rodney Schreck from Miami won both races...

The wheels I am using on the front of this car had to be specially assembled for me. 20 inch wheels with hubs that accept disc brake rotors are almost non-existent. At the local bicycle store, the proprietor and I selected a mountain bike hub that has sealed bearings and disc rotor mounting holes. Then I picked out a double wall alloy rim and the bike shop guy called his supplier and ordered them for me. $85 per wheel () and two days later I got these. The hole through the center of these is about a half millimeter larger than 3/4". The disc and brake caliper are not included in the $85; they are sold separately.

At the local ACE hardware store I found some bronze oilite bushings that are 3/4" O.D. and 1/2" I.D. The perfect solution for putting 3/4" hole bearings on 1/2" diameter axles. I failed to take a pic of them separately, but the bronze shoulder is visible here behind the nut.

This quick trial fit revealed that the 1/2" x5" bolts I had for the spindles would not be long enough. Fortunately, I had not welded them to the knuckles yet. I exchanged the 5" bolts for 5 1/2" and solved the problem.

To weld the bolts into the knuckles and assure that they are straight, I used a short piece of conduit as a sleeve and tightened the spindle nut firmly against it. Then I welded the head of the bolt to the back side of the knuckle. The sleeve not only assured that the bolt was installled straight, but also protected the bolt & threads from the welding spatter.

Steering is next! A lot of Electrathon cars have twin-lever steering because entry and exit of the car would be difficult or impossible with any type of steering wheel in the way. In this design, however, a steering "wheel" is not only possible, but preferred. It works just like the steering seen on most Go Karts; a shaft, "wheel", pittman arm, and tie rods.

The first step is to locate where the steering shaft will go. To do this, I used a piece of conduit about 4 feet long. I put one of my students in the car and determined the approximate height and angle needed for the shaft. Then with the long shaft propped in place with a piece of flat stock and a folded rag, I was able to tack-weld the upper sleeve in place.

Next, I fabricated the pittman arm from 3/16 x 1 1/4" flat steel. I have to admit here that I actually made this piece three times before I got it right. The one in the unassembled pic is the first one and it was too short. The second one was also just a bit too short. Finally, on the third try I got it long enough. I also cut the conduit shaft down to a useable length.

The tie rods are fabricated from 1/2" O.D. tubing (bought at ACE Hardware) with a 1/4-28 grade 8 bolt welded to the end. At this point, the pittman arm is still not welded to the shaft.

Awsome looking front wheels and brakes,disk do stop great

With the major components all fit, it only takes a couple more steps to finish the steering. I first welded the pittman arm to the steering shaft. I only welded it on the side away from the sleeve so that it won't grind into it and cause unnecessary wear and binding.

Next, I fabricated the "wheel" (actually more of a bar because of space limitations) from a piece of 3/4" conduit cut to 14 inches in length. I notched it in the center so that I could bend it about 10 degrees and welded it. This serves two purposes. First, it helps to keep the ends of the "wheel" inside the cowling when turning. Second and more importantly, it makes gripping it more comfortable. After climbing up on the table and slithering my fat self down into the chassis, I held the steering "wheel" where I felt it was comfortable and marked the location on the shaft. Then I climbed out, removed the steering shaft, cut it to the marked length, and welded the "wheel" to the steering shaft. Care must be taken here to make sure the "wheel" is perpendicular to the pittman arm.

Finally, I reassembled everything and then drilled a 1/8" hole horizontally through the shaft and secured it with a hitch pin (arrow).

Brakes are next! Electrathon rules state that brakes are required on at least two wheels on the same axle. On a tricycle car it is easy to use ordinary rim calipers on the rear wheels. It becomes a bit more difficult on a cycle car because there is no fork assembly or framework where a rim caliper can be mounted on the front wheels; the brakes must be mounted at the spindles. In the past we commonly used Arai drum brakes on these cars. Unfortunately, Arai stopped making those over a year ago and they are no longer available. The obvious alternative is some of the newer (and more effective) disc brakes...

After assembling the discs to the wheels and the wheels on the spindles, I held the brake calipers in place, one at a time, to determine what kind of brackets would be necessary. A little rummaging through the junk cabinet netted an 8" corner bracket that is made of 14 gauge steel - perfect!

The bodies of the calipers are cast in an offset configuration to accommodate the fork mount on a bicycle. Therefore, in order to get the calipers in their correct positions on opposite sides, the brackets are different. I started by making patterns from poster board. The one for the right side was easy and accomplished on the first try. The left one was somewhat more difficult; I configured and cut it out four times before I got it right...

Once the bracket patterns were transferred to the steel, holes drilled, and shapes cut out (with a hacksaw and grinder), I bolted them to the calipers. Next challenge was to hold them in place and mark their locations on the spindle knuckles. Once satisfied with my marks, I disassembled the calipers from the brackets and the wheels from the spindles. Then I was able to clamp the brackets in place according to the marks and weld them in place. Finally, I reassembled everything and checked for smooth operation.

Well, it's finally on its own 3 wheels. Next up... motor mounts!

OK, first step to mounting the motor is to mock it up in position. I am using a Briggs & Stratton Etek motor here (Yes, Briggs & Stratton makes electric motors!). After situating the motor where I wanted, I added two crossmembers in the frame to support it. The rear one had to be contoured slightly on the ends to get it back far enough.

After the crossmembers were welded in place, I next fabricated the bottom mounts from 18 gauge perforated angle. Yes, this lightweight stuff supports the motor just fine; electric motors don't vibrate like gasoline engines, so metal fatigue is not a problem. I cut these pieces so they are mirror images of each other, notched them to fit the crossmembers, and then folded the bottom edges upward at a 90 degree angle. The fold adds strength and also keeps the bottom edge from hanging below the frame. I mocked up the motor in place again with the mounts underneath to assure the fit and mark which holes would be used. While the motor was in place I fabricated a tab for the top mounting hole; it's a piece of 16 gauge steel, drilled, and a 5/16 -18 nut welded to it. Then I elongated 4 pairs of holes where the motor bolts down to allow for chain adjustment (I put a red outline around the elongated holes so they would show for the picture).

I mocked everything up again, this time with bolts in place. I squared everything up with a try-square and measuring tape, and tack-welded the mounts in place. Then I removed the motor and welded everything solid. Finally, I reinstalled the motor and bolted it down.