# T-Jet Magnetic Downforce: FRAY vs Ultra G



## Ralphthe3rd (Feb 24, 2011)

I was having a discussion on another Slot Forum, about the Magnetic downforce of Stock Aurora T-Jet Chassis vs. that of Cars with Neo Traction magnets. And I said, a stock T-Jet chassis, has little downforce attraction of the magnets to the track. And the one fellow countered that I was WRONG, and stated that the Lowered FRAY and SS Chassis, when using Strong Ceramic magnets -does INDEED have Magnetic down force ! Soooo, I proposed a little experiment, and although my pix here don't prove anything- since my FRAY/SS Chassis is just sitting there...I was trying to point out, that my AW Ultra-G Chassis, even with Taller Drag tires, will stick to plastic sectional track held upside Down. BUT, I couldn't get my FRAY Chassis, with Matched/Very Strong DASH Magnets, to stick to the track upside down, even with no body, and No TopPlate/Armature/Gear assembly ! For Reference, the Track I used for this experiment is a single lane of Marchon Track, which has the same highly magnetic rails as does the Original Aurora Lock & Joiner Track, which I don't really have any pieces of- except for a Few Cobblestone tracks. Anyway, the Fray Chassis is as low as I go, and I am using .348" rear Sili-sponges in this shot, and very strong magnets, and I COULD feel some magnetic downforce when held on the track up-right, but not enough to hold the bare chassis (w/mags) when held upside down.


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## slotking (May 27, 2008)

> I was having a discussion on another Slot Forum, about the Magnetic downforce of Stock Aurora T-Jet Chassis vs. that of Cars with Neo Traction magnets. And I said, a stock T-Jet chassis, has little downforce attraction of the magnets to the track. And the one fellow countered that I was WRONG, and stated that the Lowered FRAY and SS Chassis, when using Strong Ceramic magnets -does INDEED have Magnetic down force


this is more about perception i think.
like picking up a 6 year kid and saying "wow your heavy" and comparing it to picking up an NFL offensive tackle:freak:

t fray car has down force, back in the day, if a fray car pcked up a tractor pin they used to use it was not legal.

today with the dash mags, they have a lot more stick! and may folks used .332 - 340 on the rears to make better use of the mags.

but they will not compare to a car using rare earth magnets.
that like comparing the ultra-g to a Slottech cheetah and it's 6 neo mags


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## rholmesr (Oct 8, 2010)

The strong mags and low ground clearance of a fray definitely do lead to having more mag force than a std tjet would have. That is just simple physics. Surely not enough to support even a stripped car upside down on a track but it is something.

No way it could compare to even a semi-magnet car like an xtraction or magnatraction in terms of hold down force.

348 tires are pretty large for a fray car. 

Ron


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## Ralphthe3rd (Feb 24, 2011)

Ron, I never raced in the FRAY(or any other Sanctioned National Races), and I only race on Sectional Track for §hits & Grins, so I NEED to use .348" because of the rail height.
BTW- I wonder if the strongest Nacho Magnets, either Poly or Neo type would hold a Fray chassis upside down to the track ?


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## rholmesr (Oct 8, 2010)

Nachos will hold a stripped car upside down just barely. I just checked on a car with 330 rears and 305 fronts, rtho front end, abt 2 gram pu shoe tension. No top plate or body. Car in this mode weighs about 13g and add the 2x 2g pu tension it seems like the mags are providing about 17g of down force. Way more than you would get with dash mags.

Wont hold if u add the top plate.


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## Boosted-Z71 (Nov 26, 2007)

I would be really easy to get some comparison numbers from a scale setup or magnet marshal, I can tell you that on the drag Buick I set up for Sgrig's contest with the Nacho mags I was very mindful of how much attraction they had to the track and the rear axle, but I dont think it was any where near the JL t-jet with the traction mag. I have played around with some "Fray" setup cars I have built and with JL / Danny Tantrum mags you can feel some attraction through the chassis to the track but it is nothing like the traction magnet in the JL car.

Boosted


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## alpink (Aug 22, 2010)

I would think a digital scale with a clear cover could give comparison numbers for each set up and variable tire heights?
similar to how some folks match magnets?


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## Boosted-Z71 (Nov 26, 2007)

Thanks Al, that was what I was referring to with the scale setup, but the words evaded me

Boosted


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## alpink (Aug 22, 2010)

yep, I KNEW THAT .
LOL


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## joegri (Feb 13, 2008)

jeez boosted i was hoping that the gran national was retired ! ask me all i saw was tail lights!


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## Ralphthe3rd (Feb 24, 2011)

BTW, I just did another small test(no pix this time, but I can if requested). In this test, I merely set up a bare Aurora T-Jet chassis tub, and again used very strong DASH Magnets, but this time the chassis had no pick-ups, and no wheels/axles or tires either. And guess what, the bare chassis DID stick to the rails upside down !


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## Ralphthe3rd (Feb 24, 2011)

Here's a NEW Surprise ! ....I wanted to shoot a photo of my latest test with the bare chassis tub with just DASH Mags sticking to the track upside down, then I thought to myself, I wonder how it will do with a complete Top Plate(Arm & Gears) installed ? Well....here's the Result- SUCCESS ! It Sticks upside down, albeit minus the axles, wheels, tires, crown, pickup shoes w/springs, and comm brushes !










Obviously, the closer to the rails you get, the stronger the down force !


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## slotking (May 27, 2008)

really????

your gonna endanger that young girl like that??
what if car falls and she is crushed!! how will you feel then!!
:jest

Just goes to show how important shoe tensin is (or the lack therof)
using the VRP spring meter tool has really helped me setup repeatable results to find that right balance between enough tension and to much


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## Boosted-Z71 (Nov 26, 2007)

joegri said:


> jeez boosted i was hoping that the gran national was retired ! ask me all i saw was tail lights!


Joegri, You just never know what might be slipping around on the streets. Beel looking for an old Faller sedan body, something 4 door, for the sleeper look :wave:

Slotking is right that young Lady is in danger, reminds me of the super glue commercial where they glue his hard hat to a steel beam and the guy is dangling in air.

Like was mentioned, just goes to show the closer you can get that chassis to the track (even with a T-jet) the more benefits there are.

Good tests Ralph, try adding parts until it will no longer stick (remove lady first)

Boosted


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## slotcarman12078 (Oct 3, 2008)

What's next Ralph? Maybe a construction dude with his hard hat crazy glued under the track? :lol: 

https://www.youtube.com/watch?v=SXZv2KZKCCo


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## Ralphthe3rd (Feb 24, 2011)

*Test #3 (Houston, we Have a Problem)*

Oops ! ....I was afraid that might happen, just too much weight, combined with too tall of a tire = Disaster ! And wouldn't ya know it, the farmers fence next door musta been down, and well....time for another BBQ


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## Boosted-Z71 (Nov 26, 2007)

Ralph you have too much time on your hands, but hey everyone loves a BBQ

Boosted


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## rholmesr (Oct 8, 2010)

Pull that pork from the wreckage....
Mmmmmmmm....pulled pork!


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## Ralphthe3rd (Feb 24, 2011)

And later in the day.....Mmmmm....


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## slotking (May 27, 2008)

:roll::roll::thumbsup:


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## Shadowracer (Sep 11, 2004)

Hey Ralph...that 27 car sitting on the trailer in the BBQ pic...what body is that?

Trev


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