R/C Drags....

Old 03-07-2003, 01:06 AM
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Default R/C Drags....

I've heard about this before but never entered a vehicle in it to try....

Until now!

http://ebiz.netopia.com/competitionx/aetc3dragracer

This weekend, Saturday, I'm hoping to throw down some sub 2-second 132' runs, at something near (or over) 80mph.

This thing is SCREAMING to have a high speed run done....

Let me know whatcha think!
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Old 03-07-2003, 01:52 AM
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Hi Tony,

I have been experimenting with a Rail for quite some time, with very interesting results.

Someone had started a tread about drag racing Rc. in rctech. I'm sure you will find it if you go back a few pages.

Interesting to see that you are doing it with a 4wd touring car. I built my own rail running a 6 or 8 turn motor off 10 cells through a Novak Tempest. It's been pretty impressive.

We have been running ours down a real 1/4 mile drag strip. The results so far have been astonishing - 14 seconds for a 1/4 mile, with a terminal speed over 80mph.

Son Josh controls the rail from the passenger seat of a friend's MGF sports car which I drive. I tell you it's quick. It runs away from the MG for about two thirds distance, then the MG starts coming in towards the finish. But the rail is still some 50 yards ahead at the finish. The reason for driving from another moving car is mainly a question of sight. You can't see it otherwise as it disappears very quickly up the drag strip.

If we are going to carry on running a real 1/4 mile, I am going to have to do something about motors - probably go brushless, and also do some more developement on the two speed gearbox i have. Mod motors don't take too well to 14 seconds of 10 cell full power. In fact armatures rarely do more than 3 or 4 runs without tearing apart or melting.

What I am trying to do is build up some interest in drag racing out here, and then run on say 100 yards. At least 100 yard runs give you time to think, and you can stand at the start and control the car.

I've read through your site. perhaps we should be helping each other out with developement.

America being the home of drag racing, I'm surprised there isn't more Rc drag racing.

Dood luck.

Joe from sunny Malta.
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Old 03-07-2003, 04:08 AM
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Last year my son & I built a front wheel drive only TC3 dragster, based on an article we saw in RC Car Action. We used one of our old RTR kits. The car was actually set-up with the steering in the back and a solid suspension up front. You drove the car in reverse. We used a Reedy Ti 7dbl., an LRP 7.1, and 12-2400mah cells. We ground slots in the chassis for the extra battaries where the electronics usually mount for the extra 4-cells, then mounted the eletronics on the original battery strap (we used the original RTR TC3 Hitec am radio, reciever, & servo). The steering was set-up with the servo mounted on a BRP bumper, facing rearward, with Lunsford turnbuckles going directly to the steering knuckles. Everything worked great, and it screamed! We never actually raced it in competition, but it was a big hit at our local indoor track. We had 30mm pink foams up front, and 10mm pink foams out back (we cut down a set of foams for "skinnies"). We would add traction compound to the front tires and the car would still "smoke em" all the way down our 80' back straight. The cars disassembled now, but I still have most of the components. Besides having to rebuild the motor every run, and trying to charge 12 cells at the same time with 2 chargers, it was a heck of alot of fun. Maybe we should put the beast back together again!
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Old 03-07-2003, 05:06 AM
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Sounds fun

I havent tried it, but I think it would be an advantage with a belt car, since they got reduced drive train loss, while first spooled up. I would remove the front belt, diff, CVD'etc, to free up the drivetrain.
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Old 03-07-2003, 05:33 AM
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tony,

you shoul checkout this site. this shop in dallas help the national this past year for rc dragracing.

http://www.tmraceway.com/
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Old 03-07-2003, 06:56 AM
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Default Electric On-Road > R/C Drags

Guys;

Most of the R/C Drag Cars that I've seen are 2 wheel direct drive (like a pan car). There used to be a guy out here that custom made the Rail Chassis and would bring them to the on-road track to show them off. (nice and very light)
One trick he showed me was that they Soak the Rear Foams in Paint Thinner overnight to really soften them up. They look and work just like full size slicks after this.

TPhalen;

Did you know that they have an R/C drag strip over here in the City of Rialto, CA (at the airport)? I think that they hold races once a month.
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Old 03-07-2003, 06:32 PM
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That's where we are headed tomorrow!!!! Rialto. The Airport.

I know most rails are of the 2 wheel drive design. I wanted to be different.

If we get enough time, I want to mount up some rubber tires, gear this puppy up and get a full on speed run. With 100,000 rpm's on tap, I'm hoping to hit close to the 100mph mark...

Oh ya, just uploaded some new photos with the Drag Wing installed. Hopefully this will help keep this sucker in a straight line!!!!
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Old 03-08-2003, 08:33 PM
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Ok. RC Drag Racing is the total sh*t!!!!! We had so much fun it was ridiculous!!!

I ended up running all 10 cells on the 5S Hacker Brushless, while my buddy Brad threw down with 10 cells on a brushed Reedy TI 8x1. Results?? His fastest time was a 2.530 @ 53.5mph, WITH wheelspin at the line. My fastest time was 2.419 @ 62.7mph. While this seems close, we found that if I just kept gearing this thing UP, it would just keep pulling harder and harder down the track. Unfortunately I figured this out a little late and we ran out of time to keep going!

The other limiting factor was tires. All the rails were running REALLY SOFT tires on the back (almost like running marshmellows!!!!). We were limited to TC foam tires and just really couldn't get the power to the ground. We are planning on rigging up some of the softy foams on some TC wheels and going back out. All the drag guys were certain with that tire setup we could put the cars in the low 2's, maybe even tickling the high 1's!

In comparison, out of the 20 or so dedicated drag cars out there, only THREE were putting in consistent 1.8's - 2.1's. Our TC's were the next in line as most of the other cars were hitting 2.4's - 2.5's. All in all I think it was pretty successful!

I uploaded some pix of the race day and a couple videos. If you get a chance you should check them out....it's pretty cool!

Last edited by TPhalen; 03-08-2003 at 08:47 PM.
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Old 03-08-2003, 10:14 PM
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TPhalen,
Your car looks really cool! I'm curious, is it hard to keep that car straight when accelerating so hard? Did you notice if it would drift to one side, or does it track straight?
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Old 03-09-2003, 09:16 AM
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There are really two ways to do this.

The first, if you have excellent traction, is to just wood it and fight the car to keep it in a straight line. You might also have a little wheelspin at the line which will make it wander left or right.

The second, which I did, is to back off the throttle expo on your radio a couple clicks. What this does is make the throttle smoother at initial takeoff. For instance, I had pretty good traction, but I would always spin the tires off the line. This would cause the car to hesitate a tad, then I would be trying to 'steer' it in a straight line down the track, scrubbing speed. So, I put the throttle expo at -25% (to start) and the car would leave the line like it was totally overgeared....but then get full power at about 4' from the line. So, runs were pretty straight.

When we get better tires I'm gonna put the expo back to 0% and just pull-n-go! Hopefully.
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Old 03-09-2003, 09:54 AM
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Default Go Soak your Foams

TPhalen;

That was the reason for the soaking in Paint Thinner (not Lacquer) was to turn the Foams Marshmellow soft for the traction.
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