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Post by sst1610 on Dec 16, 2010 15:32:42 GMT -7
Hello,
I'm wondering how your dynamic braking shut down works. I have the 16' model, which is 15' 2'' timed and my cars don't slot down at all once they hit the shut down. I thought the dynamic braking was supposed to start spinning the motor in the opposite direction to help slow down faster. And lastly, any other ideas or options to help slow the cars down faster? I would extend the shut down length but it will have to be homemade since this company is no longer in business.
Thanks,
Dave
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Post by 440gtx on Dec 16, 2010 17:56:27 GMT -7
Hello, I'm wondering how your dynamic braking shut down works. I have the 16' model, which is 15' 2'' timed and my cars don't slot down at all once they hit the shut down. I thought the dynamic braking was supposed to start spinning the motor in the opposite direction to help slow down faster. And lastly, any other ideas or options to help slow the cars down faster? I would extend the shut down length but it will have to be homemade since this company is no longer in business. Thanks, Dave Dynamic braking doesn't spin the motor backwards. It basically turns the motor into a generator with a dead short. If you have the 16' and you are timing 15' 2" how much slow down area do you have? I have 5' of shutdown and the fast cars still make it to the end of the track. I have a towel folded up and placed as a "sand trap". With the SCI track you should have received 2 short jumpers with a magnet on both ends. Those are used to short out the shutdown rails. Just make sure that you have the plastic insulator between the powered rails and the shorted rails or you will have a problem. If you need me to, I can take a picture of the insulators and the jumpers and post them here. Matt |
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Post by sst1610 on Dec 16, 2010 18:20:33 GMT -7
Matt, I believe it's the 5' shutdown which is most likely too short for the length the track is. Where did you place the insulators? I think I had them in the wrong spot to begin with. Some of my tycos stop short now, but the muscle cars that i built for your race will go right off the end. I need to make a box at the end with some cusioning inside. I'm definitally not going to run my gassers or mmps until i figure something out to do.
Dave
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Post by 440gtx on Dec 16, 2010 19:00:27 GMT -7
My insulators are a couple inches past the finish line. We run everything at 13.8v here. That helps with the slow down. It also lets you actually see the cars go down the track.
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Post by sst1610 on Dec 16, 2010 19:25:39 GMT -7
Ok, I will try a couple different things, I also was running the cars at 24v
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Post by rickvoegelin on Dec 17, 2010 8:51:34 GMT -7
My track is a routed TKO, not SCI, but I've wired the 8' shutdown area for dynamic braking (which just means that the power rails are connected after the finish line). In my experience, downforce has a bigger effect on slowing down the car than dynamic braking -- cars with strong traction magnets stop in 3 or 4 feet, but cars with low downforce (X-Traction Musclecars, for example) can coast all the way to the sand trap (towel) at the end of the track. Pancake motors (T-jet, JL, AW) seem much less affected by dynamic braking than inlines (although my inlines also have considerable downforce).
As Matt pointed out, voltage also makes a big difference in how much speed the car is carrying at the end of the powered section, and how far it will coast. At 13.8 volts, just about every car will stop in 8'; at 20 volts, many are in the sandtrap.
Thanks,
Rick V.
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Post by allstarhr on Dec 17, 2010 14:50:16 GMT -7
This is kind of embarrassing but it worked. When I first heard of HO drag racing I knew we were going to move in a year. I wanted to get going with a track so I used Tomy track from start to 3" past the finish line.
For the shut down area I took 12 yard sticks plus 12 one eight inch by 1" steel x 36" long from Home Depot. I drilled the appropriate holes, counter sunk the holes in the steel and bolted them on top the yard sticks to a 1X4" 6 foot long piece of pine with the right gap between them for the guide pin to ride in. (The distance between guide pin slots in Tomy track just happened to be one inch which made the 1" wide steel perfect for mounting between the lanes.)
I mounted my Tomy track on another piece of 1"x4"x10' pine with the cheap $110.00 Trackmate timing system wired under the board. More 1"x4" pine boards were stood on edge and drywall screwed into the sides of the track pine to form guard rails and elevate the wires above the folding tables we used to hold it on. A totally portable drag strip!
The timed section was 10' long and the shutdown section was 6' long. Timed length= 8"-9" or 1/8 mile in 1/87th scale (Railroad HO scale.)
When the cars went past the finish line, three inches later they were on the 1/8" thick by one inch wide by 72" long steel strips that were mounted with the same pin gap as the plastic track. The guide pin stayed in the gap and the tires and shoes rode on the metal. Magnet cars stopped quick! T-jets not so quick but still OK since at that time I was using two TOmy wallwarts for power; one for each lane. Worked well till my one son left it outside in a heavy rain. Course that forced me to get a routed track built.
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Post by kdog on Dec 17, 2010 14:54:56 GMT -7
Ya know Phil...just when I think I have heard the best storys, you keep the hits comming, Merry Christmas to you, and all the Orlando Folks !!!
Please.... for all the guys.....For Christmas....we want the Smokie R. Drag Strip story !
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Post by allstarhr on Dec 17, 2010 14:57:36 GMT -7
Hi Kdog! This is not politically correct... but then none of the politicans are correct either...and my wife says... neither am I. Merry CHRISTmas to all. Ya know that shut down with the steel strips might be just the thing for the John Force/AW track shutdowns if needed.  |
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L_Brown
Pro Stock
Larry Brown - North Texas
Posts: 347
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Post by L_Brown on Dec 17, 2010 16:12:23 GMT -7
MERRY CHRISTMAS  |
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Post by sst1610 on Dec 17, 2010 16:54:23 GMT -7
Great thanks for the info guys, also I wired the track like the directions say and my 4 gear cars go backwards. Anyone know why
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Post by 440gtx on Dec 17, 2010 17:10:02 GMT -7
if you have the negative power lead on the right hand rail (passenger side of the car) and the cars run backwards, the motor magnets are probably in wrong. On a 4-gear chassis the red magnet should be in the front. On a 3-gear chassis like a magnatraction/x-traction the red magnet is in the rear.
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Post by sst1610 on Dec 17, 2010 17:59:51 GMT -7
Ok thanks Matt
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Post by mobydidit on Dec 19, 2010 20:15:29 GMT -7
I use 1/4" thick 1" wide steel for shutdown rail. Stops the magnet cars very quick. Its made with 4 6 foot long pieces & the cars ride on top of it. They are screwed down & spaced apart to create a guide pin slot.
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Deleted
Deleted Member
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Post by Deleted on Dec 21, 2010 7:51:53 GMT -7
I have raced on Moby's track and it does work well. so much so that I convinced my partner, Hank, to do that for his portable 1/64 scale drag strip. the racers are happy too. Happy New Year everyone.
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