# Traction magnets



## T-Jet Racer (Nov 16, 2006)

Hey I got a Johnny lightning chassis I glued on the rare earth dot magnets from radio shack What a blast!! Anyone else doing this? Folded the tops of the pick ups over adjusted the wipe on the rails the car is an animal! I put a moldel motoring vette roadster body on it. I got to get some video of this thing running it's wild!!! :thumbsup:


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## *MAYHEM* (May 4, 2007)

I've done that with several Chassis over the years. Another good way to do it is using the traction mags from the lifelike T chassis and drill holes into the frame to mount them above the pickup shoes and in the rear just behind the motor mags. They'll corner like crazy and if you don't set them too low you'll still get great speed.


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## T-Jet Racer (Nov 16, 2006)

I tried to glue the mags on the pick ups once car failed to move! The things we will try....


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## JordanZ870 (Nov 25, 2004)

I do the "dot" trick so I am not playing permanent Corner marshal to my 7 yr old. He thinks he is a great driver and I get to actually RUN my slot cars! :thumbsup:


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## skrcustoms (May 15, 2007)

They (rare earth) work great for drag racing also when using high voltage.


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## sethndaddy (Dec 4, 2004)

T-Jet Racer said:


> I tried to glue the mags on the pick ups once car failed to move! The things we will try....


Try gluing it on the back right behind the pickup shoes. on plastic. I have not had one fall off yet, even with Speed Racer Seth air patrolling with cars to the floor on a daily basis.


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## keionius (Aug 22, 2007)

Cant say that i've tried this trick yet, but i will definately give it some thought.


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## sethndaddy (Dec 4, 2004)

at a price of $1.98 for 2 magnets you can't go wrong. Just walk into any radio shack and ask where their rare earth magnets are.


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## keionius (Aug 22, 2007)

How about mounting them on the motor magnets.


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## TK Solver (Mar 18, 2004)

I read somewhere that just one of these per car works fine. Can anyone verify this?


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## T-Jet Racer (Nov 16, 2006)

TK Solver said:


> I read somewhere that just one of these per car works fine. Can anyone verify this?


It works well with one but if the car gets sideways somtimes it stays that way for a while because the magnet grabbed the rail on the opposite side before going off. if you use the stock size wheels for AW on a t-jet the second magnet will hit the rail. so it needs to be worked out.


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## T-Jet Racer (Nov 16, 2006)

sethndaddy said:


> Try gluing it on the back right behind the pickup shoes. on plastic. I have not had one fall off yet, even with Speed Racer Seth air patrolling with cars to the floor on a daily basis.


Yea that is where I put them. I only tried the shoes to see if it would work. if they were drilled into the plastic above the shoes it would work great. If you do this you need smaller magnets.


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## RiderZ (Feb 19, 2007)

Could someone post a pic on where to glue the magnets?


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## zig (Mar 11, 2004)

keionius said:


> How about mounting them on the motor magnets.


There is an old trick to mounting them onto the motor magnets in an aurora slimline chassis to help make the magnets stronger... don't know why it wouldn't work on other types of chassis.


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## videojimmy (Jan 12, 2006)

I've used the rare earth magnets as well, with good results. I've also used them with motor magnets on a slimline. They seemed to help push the motor more. Those slimline magnets are weaker than weak.


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## TK Solver (Mar 18, 2004)

I tried it last night on a couple of the Bowtie Brigade cars with RRR custom wheels and relatively high centers of gravity. Without the magnet, they were touchy to drive. I glued a single Radio Shack magnet to the plastic on the bottom of the chassis just in front of the left rear wheel. It fit perfectly. I don't have a picture handy but I hope that's easy enough to visualize. This morning's test drives went just as I'd hoped. No more silly deslots. They still drive like TJets -- but with a feel of a lower center of gravity. I have a couple dozen very nice looking cars with custom wheels that are good candidates for this modification.


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## Gary#8 (Dec 14, 2004)

Hey T-Jet racer, We have been doing that for a couple of years now. The Johnny Lightning chassis are the ones to use. We also use the Radio Shack rare earth magnet. We super glue one on the left side bottom(left is driver side-right is passanger side) just behind the motor mag. If it sits to low grind away some chassis in that area so the magnet can be mounted higher or use taller rear tires.Try taking the front wheels off and see how fast they go.(need to remove front body screw and super glue guide pin on and use very small counter-sunk screw to hold body on in front) With guide pin glued on try getting the chassis to handle without body first.Then on the front use a Brass front (FRAY style) end with tires ground down so they just touch the track.Then you will not need a magnet in the front by the pick up shoes! These cars fly!!!! Almost as fast as a stock 440x2 widepan Tyco. Add a lexan body and ever faster! To add a "cheater" Radio Shack rare earth magnet take car apart, then on far right side, drill or grind a hole the size of Radio Shack magnet inside chassis where rear motor magnet goes. I use an exacto knife to finish opening bottom of new magnet hole after drilling. Be carefull not to damage or dimple metal ( copper or silver) riveted brush arm area(this piece of metal is what holds and hides Radio Shack magnet). Drop in Radio Shack magnet, put in rear motor magnet on top of Radio Shack magnet and put rest of chassis back together. Now if done right when you look at bottom of chassis it will look stock. Put Tuff ones rear tires or shorter on back and you will have a "Cheater ThunderJet". or "MagJet" as we like to call them.


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## T-Jet Racer (Nov 16, 2006)

Gary#8 said:


> Hey T-Jet racer, We have been doing that for a couple of years now. We also use the Radio Shack rare earth magnets. We super glue one on the left side bottom(left is driver side-right is passanger side) just behind the motor mag. If it sits to low grind away some chassis in that area so the magnet can be mounted higher or use taller rear tires.Try taking the front wheels off and see how fast they go. On the front use a Brass front (FRAY style) end with tires ground down so they just touch the track.Then you will not need a magnet in the front by the pick up shoes! These cars fly!!!! Almost as fast as a stock 440x2 widepan Tyco. Add a lexan body and ever faster! To add a "cheater" Radio Shack rare earth magnet take car apart, then on far right side, drill or grind a hole the size of magnet inside chassis where rear motor magnet goes. Be carefull not to damage or dimple metal ( copper or silver) riveted brush arm area. Drop in Radio Shack magnet, put in rear motor magnet on top of Radio Shack magnet and put rest of chassis back together. Now if done right when you look at bottom of chassis it will look stock. Put Tuff ones rear tires or shorter on back and you will have a "Cheater ThunderJet". or "MagJet" as we like to call them.


putting it in on the inside sounds great, I have to try it so it has the " stock" look Thanks for the input


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## keionius (Aug 22, 2007)

I'll have to give it a try. Thanks zig.


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## Bro-man44 (Feb 7, 2007)

Hey guys,
Been following this thread and am very interested in trying some of the ideas posted here. Has anyone checked out one of the sponsers here on HT? Magcraft Super strong rare earth magnets at the bottom of our page. They sell in bulk and I believe in small amounts also. They also have a variety of other types. Someone PLEASE send pictures of how they attach the magnets!!  Heres the link:
http://www.rare-earth-magnets.com


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## TK Solver (Mar 18, 2004)

Sheesh, Magcraft's price is just $8.99 plus shipping for 100 magnets. Shipping to my address is just $5.35 by Fed Ex Ground. That's less than 15 cents each. I don't have a need for 100 of them (yet) but at that price it seems like one of the slot car dealers could buy some and sell them for as much as 50 cents each to go along with other slot car orders.


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## T-Jet Racer (Nov 16, 2006)

TK Solver said:


> Sheesh, Magcraft's price is just $8.99 plus shipping for 100 magnets. I suspect that shipping would be more than the magnets. Even if shipping is $11.00, that's only 20 cents a piece. I don't have a need for 100 of them (yet) but at that price it seems like one of the slot car dealers could buy some and sell them for as much as 50 cents each to go along with other slot car orders.


Yea, their price for the magnets is great. I am getting a 100 pack so when I order it I'll let you know how bad the shipping was....


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## Montoya1 (May 14, 2004)

Is this not what AW have done with the new Ultra G?


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## T-Jet Racer (Nov 16, 2006)

Montoya1 said:


> Is this not what AW have done with the new Ultra G?


It sounds like it from what I have read on their website, We will have to wait and see how strong their net chassis is in the GRIP dept. Anyway this was nothing new but I had never done it to a car and ran it on a large 4 lane track before. With 2 of these magnets I dont think the car would ever deslot. 1 magnet still gives you the need to monitor the power input or off you go.


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## jamiestang (Dec 15, 2006)

K and J magnetics here in Jamison PA has some alot of different shapes and sizes of magnets at good prices. 

Id like to see a pic of these radio shack magnets


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## mikeponiatowski (Jan 24, 2006)

*I also use Rare Earth Magnets.*

I also use the small round Rare Earth Magnets on my Aurora T-Jet GT type and Indy cars. However, I install them quite differently from others mentioned. 
1. I split them in half using pliers w/a wire cutter edge. I use Crazy glue to install one-half on each side of the under-chassis just in front of the rear tires. 
2. You need to be very careful to make sure they are split down the middle. This can be tough to do with such small magnets. I have ruined a few getting the hang of it. 
3. I have found that there is still clearance under the track when using Tuff Ones or LowPro RRR wheels and tires. See pictures.
4. I do not add any weight or magnets to the front. They are still T-Jets and I believe some level of driver skill needs to be part of the equation.


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## mrwillysgasser (Jan 3, 2002)

The new utra-g chassic has one installed allready! New casting on chassis with place for magnet cast right in.


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## TK Solver (Mar 18, 2004)

I've done quite a bit of testing the past few days, and a single driver-side magnet seems to eliminate the need for restricting the pick-up shoe travel and overcomes problems with rear axle hole slop. I wonder what the pull force of the AW magnet will be. According to the MAGCRAFT calculator (http://www.rare-earth-magnets.com/pull_force_calculators.htm), the Radio Shack magnet should have a pull force of about 1 pound. That seems to work well. I've read that some of you use one on each side. That would be pretty potent, especially if the one on the passenger side is even closer to the rail. Those motors probably heat up a bit.

The smallest MAGCRAFT round disc (.125" diameter and .063" thick) has a pull force of 0.67 pound. Those sell for roughly 15 cents each, shipped. MAGCRAFT also has a .25" square by 0.1" thick magnet with a pull force of 2.4 pounds. Those sell for about 30 cents each, shipped. Has anyone ever tried those squares? A single square would fit nicely on the plastic just ahead of the driver side rear wheel and be a lot cheaper than two Radio Shack discs, with just a bit more pull force. My fear is that they'll wear out the motors though.


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## mtyoder (Jan 3, 2004)

Oh yeah, we been doing this for years. Once you reach a certain point with modification those little magnets are mandatory(wheelie bars too)! I like the sound of those little square magnets. Hafta checkem out!


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## Slott V (Feb 3, 2005)

Just a safety reminder: IF anyone decides to grind magnets, you should very cautious about not inhaling the dust or grindings or it can cause respiratory problems! :drunk: 

Also, if you allow neodimuim magnets to snap together, or if you bang them they will lose their strength.


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## Lype Motorsport (Mar 14, 2004)

*Magnet Location Pic HERE!*

Hi Gang
Heres a pic on where to put the magnet on a T-Jet. We have been runnin them on not only JL/Round2/AW T-Jets since they were first introduced, we also run them on Aurora T-Jets since the mid '90s. I usually use a good CA (super) glue to attach then let them dry for a few minutes before running. Hope this helps


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## TK Solver (Mar 18, 2004)

The reaction forces on the four wheels can be modeled by the following set of equations:

R1 + R2 + R3 + R4 = F 
R1 = F*((1-x/W) * (1-y/L))
R4 = F*(1-x/W) - R1
R1 + R2 = F*(L-y)/L

R1 is the reaction on the rear wheel opposite the magnet. 
R2 is the reaction on the rear wheel nearest the magnet. 
R3 is the reaction on the front wheel nearest the magnet. 
R4 is the reaction on the front wheel opposite the magnet. 
F is the pull force of the magnet.
x and y are the magnet center coordinates, looking down at the bottom of the chassis, where (0,0) is the middle of the wheel opposite the magnet.
W is the width; roughly the axle length.
L is the wheel base; the distance from the rear axle to the front axle.

I don't have a car in front of me right now for actual measurements, but assuming L=2.5, W=1, x=0.8, y=0.2, and F=1, the force is distributed to the wheels as follows...

R1 = .184
R2 = .736
R3 = .064
R4 = .016

Just 8% of the force is impacting the front wheels. Still, that's about 29 grams to the magnet-side front wheel and 7.25 grams to the opposite front wheel. The one pound of force is an estimate based on the Magcraft web site. That's the maximum force when the magnet is actually attached to an object. In our case, the force may be considerably less depending on the distance from the rail to the magnet. In fact, the force falls off as the inverse cube of the distance. If the magnet is touching the rail, the distance is half the thickness of the magnet. Double that distance and the force is reduced to 1/8th of the max. So, assuming the magnet is 0.1" thick, if the magnet is .05" from the rail, the force would be just 1/8th of a pound.

Here is a formula you can use to compute the resulting magnetic force based on the distance from the magnet to the rail, the thickness of the magnet, and the nominal force of the magnet...

Force = NomMagForce * (2*distance/Magthickness + 1)^-3

Of course, this still doesn't answer the question as to whether a single magnet will cause the car to turn left or right faster... but it is a light on the path.


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## T-Jet Racer (Nov 16, 2006)

TK Solver said:


> The reaction forces on the four wheels can be modeled by the following set of equations:
> 
> R1 + R2 + R3 + R4 = F
> R1 = F*((1-x/W) * (1-y/L))
> ...


Ab use the FORCE LUKE!


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