141 replies to this topic

[GE53]

Working as a welder for many years using 3/32 tungsten, 2% thoriated, if dropped on the floor they would break.  

[Martin]

Mike, I have crashed plenty of times while welding and have never snapped one.

It sure seems strong to me but I can test it compared to a drill blank axle.

 

Well I just did the drop test with 2% and pure Tungsten. I dropped them several times and when they did not break I threw them several times onto a concrete floor still no break. I finally got the 1/i6" to shatter and I chipped the concrete. I mean I threw it hard.  Its is brittle and it is heavy only testing will show its +s and --s in our slot car world. we shall see.

Paul found a carbon fiber axle so we will see on that. I work with Carbon fiber and it wins in most engineering situations. Anybody out there tried or use them?

I am old school most of my cars have threaded axles. But I do remember 1/8"fiberglass axles used in the front, and 1/8" aluminum axles made by Russkit cars back in the day.     

[MSwiss]

Trying to get used to a new phone, so some of posts may be goofy at first.

 

Anyway, if tungsten was the best to use for slot car axles, that's what would be used.

 

As far as Pablo's issue, I forgot I had a couple wing cars with the Phoenix that are built up, by someone else , for me, that just waiting for the lead wires to be attached.

 

As long as the axle is supported by both bushings, that axle seems perfectly aligned, albeit with a bit of magnetic drag from the powerful Phoenix NEO mags.

And as one would expect, as soon as you pull the axle through, the end attracts to the can.

 

The moral of the story.

 

Always use 2 bushings, and keeping them adequately lubed, is probably a bigger priority than before.

[Pablo]

I put a spur on the wrong end of my axle and a dummy keeper on the pinion end, then tried to spin the axle.

It rotated twice and stopped  

[MSwiss]

If you are going to race, running around the track, spinning the tire with your index finger, you probably want to go to another motor.

 

But if you are going to race conventionally, I would just use the most rugged axle you have, and not worry about the magnetic drag, when this motor is running 50-100K RPM.

 

Again, as I mentioned, these motors have been raced for months, including an LMP(?) enduro, at BP.

[Pablo]

In the end, I may have to do exactly that - shut up, don't worry, and race.

But I'm still going to test lap times with a non-magnetic axle.

 

If I fail it won't be my first failed experiment

[Bill from NH]

Mike, is magnetic drag on the rear axle ever an issue with Grp. 27 & 7 wing cars? I would think the cobalt magnets used in both classes would be far stronger than the Phoenix neos.

[MSwiss]

What it ever an issue?

 

No.

 

We weren't going to race with an inferior axle to eliminate it.

 

I just did a quick experiment with the pictured car, the Phoenix in one of my Group F chassis., and what was a G27 car to beat , back in about 2006, running 2.0 laps on my non-Gerding King.

 

The Phoenix motor definitely has a stronger attraction to a steel axle, than the 6(?) mag G27 motor.

 

WAG, 30% more attraction.

 

If it hasn't been already mentioned, the Phoenix has solid NEO, not poly NEO blend, mags.

 

They are bigger, in every direction, that what is raced in G27 and G7, and the thin FK can probably allows more leakage.

[Pablo]

Axle experiments - I have 3 axles, all same length, to test using the Phoenix motor.

 

The Koford M623R is the "gold standard", weight is 1.9 g, ultra hard, very attracted to the Neo mags.

These are so straight, on the dial indicator the needle seems like it's stuck. And they don't fail, period.

 

The tungsten fits the bushings fine, weight is 4.6 g, seems hard, not near as straight as the Koford, but it's not bad at all. Good enough to race, straightness-wise. And, of course, zero attraction to the motor.

 

The carbon fiber also fits the bushing fine, weighs 0.4 g, doesn't seem very hard to the touch - when you tighten a set screw on it, it galls it. Strength - feels like I can bend it with my fingers but has strong "memory". No attraction to the motor, of course. Straightness is hard to assess because of the strange surface, but on the dial indicator it seems to at least as straight as a budget axle. Seems worthy of a race test.

 

 

The next part of my backyard experiment was to check amp draw at 3 volts with each axle and a gear.

Then the Phoenix suffered catastrophic failure. Power supply was acting really goofy so I knew I had a problem.

 

Holy Cow, Bunky, BOTH BRUSHES HAVE DEPARTED THE HOLDERS

 

End of experiment for the day

[Pablo]

Let's investigate this motor failure. Why did a brand new motor - never even been on a track - drop BOTH brushes out? I've been racing FK motors for years and never seen this until now.

 

Motor is out of the chassis.....

 

 

Despite using my inspection flashlight, 3X reading glasses, and geezer goggles, the brushes are nowhere in sight. So I'll now remove the endbell and take a look.

[Pablo]

No wonder I couldn't see where the brushes went - they got pulverized and splattered all over the EB

 

 

Comm failure combined with brush failure = "poof"

 

 

Never even got to test it on a track, my axle "anti-magnetic" experiments were for naught, and I made myself a fool by ordering carbon fiber axles in anticipation of the Phoenix being "the next best mouse trap". I think the only thing got trapped is, me

 

 

[Bill from NH]

In the photo, the top comm segment appears to have partially lifted from its binding material. If so, the comm could have eaten soft brushes. Hang onto the magnets & can for a future build.

[havlicek]

Hi Pablo,

     From the (very nice) photos, it looks as though all the coms segments have let go from the phenolic core.  These coms are sort of like the old Mabuchi coms, with the plates just sitting on their core, instead of forming the inside of a copper shell with "dovetails" to help key them to the phenolic after slitting, the way modern "actual" slot car motors are done   I'm surprised that more of these motors don't suffer the same fate as yours did, but many/most DO last for the expected lifetime of the motor.

***Here's the thing, phenolic resin is very tough stuff...like REALLY tough stuff.  Just as your photos show, it's most often not the phenolic itself that fails, but the connection ("bond") between the copper shell and the phenolic.  When (*I think it was) Gunther Faas figured out how to improve the situation by dovetailing the inside of the copper shell before filling it with phenolic, com reliability took a major leap forward.  I have some Faas com shells that haven't been filled, and they look fully like those we see today.  The only thing that has changed on some coms is the number and shape/geometry of the dovetails, with some having 12 instead of 6.  Personally, I have my suspicion that doing that many dovetails can make for a slightly weaker com than having 6, but it may also be the depth and width of the dovetails.  The rocket scientists can figure that one. 

Anyway, these Phoenix motors are basically like hot-rodded Falcons.  They may have a good balance between magnet strength and wind and still last OK, but the basic setup is being "asked" to do significantly more than your average sealed motor.  You may have just been unlucky, or maybe there will be *on average* more failures like this with them???

[Pablo]

At least it failed at home, not during a race 

The guys who bought a whole bunch of them now have to be wondering.........

I think at this point it would be prudent for me to install a Hawk 7 and a Koford axle

[boxerdog]

The axle experiments would still be interesting. 

[Pablo]

Concur. Stay tuned and it will all play out, hopefully to include the Windmill Experiment.

There are probably other "test-monkeys" that will be using the Phoenix and may volunteer to try the CF axle.

[Pablo]

We had a good field of karts today at The Dungeon. The rule changes that disallow added air control (other than a spoiler) and mandate a permanently sealed FK type motor of your choice, seemed to encourage more participation.

 

Only two racers chose to use a Phoenix. Everybody else used Hawk Retros or Hawk 7's.

I guess my blown Phoenix at home was just a fluke - neither of the 2 Phoenix motors in the field failed and both still had plenty of brush life left.

 

I spread a few CF axles around in case anybody wanted to try them, and nobody did - not yet, anyway.

The Windmill tungsten axle is still in my box. Maybe after everybody re-thinks and re-groups, someone will want to try them.

 

My intention for this thread isn't to brag of my race results, but I won today's race with a Hawk 7.

It had more than enough power for a kart.

 

My opinion is, the Phoenix is too much punch for a kart. But if a racer has the skills to drive one into the winner's circle, I applaud it. That's why I worded the rules the way I did: Motor must be an FK type permanently sealed non-rebuildable motor with internal non-serviceable brushes.