Discussions on buying, building or rehabbing a race track. Topics like plans, materials, tools, construction, finishing, commercially available tracks, and so on.
- Pine Head Legend
- Posts: 2646
- Joined: Wed Jun 17, 2009 2:49 pm
- Location: Boogerton, PA
SlartyBartFast wrote:Has no one thought about using gravity to slow the cars down?
Well, I know I've thought
about it. But I haven't thought enough to build one that would work well (meaning efficiently or economically, and partly for reasons Speedster noted). I suspect others have thought about it even more, with the conclusion being the conventional skid-type systems. A car actually loses relatively little speed in the flat; without additional braking a car starting at 4' needs to climb to ~3.5' to come to a complete standstill on, say, a 32' track.
Good to see a post from you again, SBF!
- Pine Head Legend
- Posts: 6888
- Joined: Sat Jul 05, 2003 7:01 pm
- Location: Morton, Illinois
FS, your readers should remember that they want the car to stop ... and stay stopped at the end of it forward movement... no rebound, no rolling back down the hill. That means that the friction pad surface needs to be retained whether the end of the braking section is elevated or not.
It is interesting that even a small amount of elevation helps the friction surface do its job without increasing the risk to the race car. Elevation provides two values: First raising the car converts kinetic energy to potential energy. Second, pitching the direction of travel up temporarily increases the force of friction between the car belly and the friction pad!
"If it's not for the boys, it's for the birds!"
- Posts: 13
- Joined: Sun Feb 19, 2012 3:40 pm
- Location: Louisville, KY
Thanks to all on Derby Talk I added a friction brake to a old SuperTrack that had one of the old hard foam stop end sections. We didn't try the new SuperTrack memory foam stop section because we were still not sure a hard stop section was a good idea, even though it looks as though it may be better than the old foam stop section.
I modified the friction brake section somewhat from what others have done for other tracks. It had to be a little different because of no center rail on the track. Everything worked great although I believe next year I might try some more modifications to make it work better. This year I kept from modifying the SuperTrack at all (no cutting or drilling holes) just incase the end section didn't work. I used Nance 2-1/2" x 25' Rug Tape Item #: 92623 from Lowes on the rails even though I did eventually buy the natural rubber from http://www.mcmaster.com
" target="_blank but didn't change it out since the rug tape was working. Notice I didn't use the rug tape on the whole length because it stopped the car too soon (in the transition section or tapering center rail) and the car slid to the side of the rail. Allowing the car to easily slide on the center rail through the transition kept the car on the rail until the rug tape where it then slowed it down. I also included dividers between rails to keep cars leaving the rails and hitting other cars. The stop section was 4 feet long and used cut up grout sponges for the final backup stop, against wood, if the cars made it that far (they didn't). Note the duct tape was just to keep the end section in place so the kids wouldn't move it. I also added a threaded eye hook to the front of the end section to connect the start section of the track to the brake section by rope (as is recomended by the manufacturer) to keep the track from coming apart.
- Pine Head Legend
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- Joined: Fri Jul 18, 2003 1:23 pm
- Location: Mountain View, CA
Darin McGrew wrote:Our stop section uses the non-slip safety tape. It holds up great (it's designed to be walked on), although I haven't compared its stopping ability for derby cars to other materials.
Sunday afternoon, we got the track down to check it out, and experimented with ideas to improve the brake section. The technique that worked was to replace the non-slip safety tape on the raised center rails with soft rubber weatherstripping. We aren't sure how durable the weatherstripping will turn out to be, but it isn't expensive, and even if we have to replace it every year, the much improved braking will be worth it.
For the record:
Elevating the raised center rail an inch or two didn't have a noticeable effect, and we weren't comfortable elevating it further. And we were able to determine that redesigning the stop section so the track drops out from under the wheels would put the cars in contact with the center rail only a few inches earlier, which wouldn't be worth the trouble of redesigning the stop section.