# T jet pancake arms and magnets



## cheftoo (Jan 24, 2017)

What type of magnets are best paired with low ohm armatures? 
16 ohm seems to be the standard for stock arms. I have a couple that are closer to 6 ohms. How will these low ohm arms perform with stock magnets? What is the best combination for these low ohm arms?
Thanks


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## alpink (Aug 22, 2010)

6 ohm arms perform much better with polymer magnets.
be careful ... NEO magnets are very strong and require 2 OHM or less custom winds with a lot of other customization to chassis running gear.
if you are allowed, find some silver content motor brushes too.
original Aurora T-jet hop up (silver content) brushes can still be found NOS.
there have been some other manufacturers that made them as well.
original Aurora AFX domed brushes have silver content.

shunts between the pick up shoes and the chassis help a lot as do braid added to the pick up shoes.
that is a little advanced and requires soldering, but I thought it was worth mentioning.


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## slotking (May 27, 2008)

the dash mags also work well with 6 ohm arms.
but you should use any where from old super II mags up to the poly mags.


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## Rich Dumas (Sep 3, 2008)

You did not say what sort of racing you intended to do or what kind of car for that matter. It is nice if you know how strong your magnets really are. Ceramic magnets can vary greatly in strength, even if they are the same type. I have a magnetometer and I measure all of my magnets. Years ago I bought some Aurora Super II magnets and those measure from 850 to 1100 gauss. The earliest Aurora T-Jet magnets might measure as low as 450 gauss. Johnny Lightning and Dash ceramic magnets measure between 850 and 950 gauss. Polymer magnets will be stronger than any ceramic magnet and those are available in different strengths. Neo magnets are the strongest type, they are also available in different strengths, but they can be somewhat more fragile in that the will loose strength if the are mishandled. 
For a particular armature there is a limit to how strong the magnets need to be. My own testing indicates that the power that the motor will put out is not directly proportional to the strength of the magnets, doubling the strength of the magnets will not double the power.
As has already been stated lower ohm armatures run better with stronger magnets. All 6 ohm armatures are not created equal, two different examples that do not have any obvious defects can have greatly different performance levels. Some of them are no better than a good 16 ohm armature. If the arm that you have is a dud you might be wasting your time fussing around with magnets, on the other hand it never hurts to experiment a little. The strength of the magnets will also have some effect on the way that a car handles.
Silver is only a tiny bit more conductive than copper, modern 85% copper brushes from Wizzard or Slottech might be better than the old Aurora silver brushes. I have some JB's silver brushes, I don't know if those are still available. I would expect that more powerful armatures would tend to be more fussy about the brushes that you use, so you might as well try different types.


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