# Tyco 440 arm question



## Pete McKay (Dec 20, 2006)

Anyone know the degree timing on a stock 440X2 arm? Also, which way do you change the timing for more torque?


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## SwamperGene (Dec 1, 2003)

Stock Tyco arms are neutral, or "0" timed. You would retard the timing for more torque.


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## Pete McKay (Dec 20, 2006)

SwamperGene said:


> Stock Tyco arms are neutral, or "0" timed. You would retard the timing for more torque.


OK, then that answers my next question about arm rotation and moment of inertia for chassis loading. With an arm rotating clockwise (looking from the back) the chassis is loaded on the left side under acceleration. Now I need to figure out how much yaw is translated to the chassis with the arm rotating in either direction.

The 440X2 chassis with traction magnets exerts a force of 260 grams average, with the magnets removed it's only 180 grams average. With the magnets removed they should behave more like an old G+ car, which is where we're going.


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## Hornet (Dec 1, 2005)

Grab the com on a stock Tyco arm,there's enough play in the wires and internal locking tabs,you can usually get a couple degrees timing either way out of them ,by just twisting the com till the wires pull tight,then glue it where you want it .Disect a dead arm,and pull the old com off,it'll give you lots of insight into some old time speed tricks,specifically look at the lock tabs etc.,you'll see they have lots of room to move around.Personnally i even wondered if the timing didn't change while the arm is in the car,under varying load conditions,or if the car took a good wall shot,etc.
But Gene's right,they are generally regarded as 0 timed


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## SwamperGene (Dec 1, 2003)

Geez Rick, that ain't no old time speed trick anymore, that's a trade secret!

:jest:


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## Pete McKay (Dec 20, 2006)

Geez guys. I'm trying to curb the cheating, not endorse it.

I've already thought about the hard tires and alcohol rule. I used to soak my hard tires in alcohol, it made them really sticky and when taped would keep some of the glue off the tape. It took the promoter half the series to figure that one out. Then there was the 'ol stiffer outside shoe spring trick that some say worked, some said it didn't. Outlawed never-the-less though. 

I used to run those 440X2 tires that had the hump around the middle (called "humpers" for that) to put a little stagger in my sprinter. And don't forget the spring loaded front end that would make it through the tech block but would stick out too far once on the track and trip up anyone passing on the outside. 

The arms are the least of my worries since all the rules say is they have to be stock. Chassis lowering and guide pin rules will be the toughest to monitor.


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## AfxToo (Aug 29, 2003)

> Personnally i even wondered if the timing didn't change while the arm is in the car,under varying load conditions


Magnetically speaking, the timing absolutely does change with loading due to armature reaction. The magnetic field in the arm skews the magnetic field between the motor magnets, which alters the timing. The effect is more pronounced with increased load because it causes increased current flow in the arm and a stronger magnetic field to be generated in the armature. This is the reason why large brushed industrial motors have had movable brushes for many decades. However, for little slot car motors, armature reactance has a much more pronounced relationship to motor timing and performance than armature reaction.


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## Pete McKay (Dec 20, 2006)

I was speaking more of torque loading but that is pretty interesting too. I've read that some larger scale cars change the direction of their motor rotation on ovals because of the momentary torque input from acceleration. I'm not sure how this applies to an HO car. It may be a lot like aerodynamics, a matter of splitting hairs.


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## AfxToo (Aug 29, 2003)

When you're looking at the total magnetic downforce on a chassis like the X2 (and others of similar design) you really have to consider the resultant of 5 magnetic influences: the 2 motor magnets, the 2 traction magnets, and the electromagnet formed by the energized rotor pole. All of these have a significant impact on the dynamics of the car. Anyone who has played around with low downforce vs. high downforce traction magnet setups understands the interaction between the motor magnets and the traction magnets. Few people consider magnet #5. 

I'm a bit confused by the term yaw as used here. Yaw is movement in the azimuth, a force I would expect with a pancake motor powered car. With an inline I would expect "roll."


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## SwamperGene (Dec 1, 2003)

AfxToo said:


> Few people consider magnet #5.


So, so true, in fact I said long ago that that is the one reason a magnet marshall could fail as an HO tech device as 4 "matched" sitting HO cars will not likely be so under track power.

You wanna see scary magnetism? There's a magnet modeling program you can download, lay out a four mag diagram similar to a slot car, then watch what happens to the fields when you throw a fifth down the middle....then imagine that fifth magnet spinning!


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## 1976Cordoba (Sep 20, 2000)

Pete McKay said:


> I was speaking more of torque loading but that is pretty interesting too. I've read that some larger scale cars change the direction of their motor rotation on ovals because of the momentary torque input from acceleration. I'm not sure how this applies to an HO car. It may be a lot like aerodynamics, a matter of splitting hairs.


I always went faster on big ovals when I spun the motor towards the inside of the turn; i.e. counterclockwise when viewed from behind.

For me, it was one of those moments of enlightenment where you go, "HEY! - What if . . . " on a hunch and low and behold if it didn't work.

I think it may be torque-related . . . or maybe the re-arrangement of the motor mags helped to aid the traction mags also . . . not sure but it was good for a couple tenths.


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## Hornet (Dec 1, 2005)

LOL,i think you guys are starting to over analze things a bit.
Show me somebody who's set-up to visually utilize the 5th magnet,cause your gonna have to see your results before you can do anything,and me,i'm not overly interested in sitting my high dollar toy cars in a pile of magnet filings then nailing the throttle,and spinning it up to speed.Theories are great,but you gotta be able to utilize them and the info they potentially can give you with the right kind of testing.
Practice is your best theory,it'll never let you down:thumbsup:


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## AfxToo (Aug 29, 2003)

I wouldn't get anything useful out of visualizing the magnetic fields because I only care about the net result. But it would be interesting to use a guassmeter and map out magnetic strength at various points along the bottom of the chassis and magnetic surfaces, with and without the motor running. It would be informative. If you want to see the interaction between the motor magnets and traction magnet you could remove the tractions and do a before-and-after set of measurements. I've never tried to do a full mapping, just quick and dirty ones to see the boosting effect that Phase II tractions have on motor magnets.

The fully energized pole is always on the same side of the arm but it's not constant strength as it goes through a charge and discharge cycle before and after being in the fully energized state. The net effect would be to influence the resultant field on one side of the motor. 

I totally agree, nothing beats practice and experience. The top builders know what it takes to build a fast car and most of the experience was gained through trial and error and testing testing, and more testing. The science can give you some good hints about areas where potential gains could be made, or help explain why a particular adjustment has the effect that it does. But the final result is still in the builders and drivers hands.


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## NTxSlotCars (May 27, 2008)

AfxToo said:


> When you're looking at the total magnetic downforce on a chassis like the X2 (and others of similar design) you really have to consider the resultant of 5 magnetic influences: the 2 motor magnets, the 2 traction magnets, and the electromagnet formed by the energized rotor pole. All of these have a significant impact on the dynamics of the car. Anyone who has played around with low downforce vs. high downforce traction magnet setups understands the interaction between the motor magnets and the traction magnets. Few people consider magnet #5.
> 
> I'm a bit confused by the term yaw as used here. Yaw is movement in the azimuth, a force I would expect with a pancake motor powered car. With an inline I would expect "roll."


I have experienced the fifth magnet. I think it's something most racers have run across from time to time, but didn't really know what it was. It seems to have more effect the longer you watch a slot car at speed, with a full load. Deslotting ends the effect. Toward the end of a three minute heat, if you are fortunate enough not to come out, you will notice a hypnotic effect as every acceleration and deceleration seems to become very exaggerated. The table seems to sway with every movement of your car, as your vision starts to tunnel. The car's magnetic force seems to draw you in more and more. Your eyes get dry, but you can't blink, you just can't look away. Time stands still, you start to lose your balance. You use every muscle in your body, every ounce of energy to keep the car on the track, at speed. You just can't seem to hang on.....it's almost a fifth dimension. 

That's when the power cuts off and someone yells"That's a heat!"

You can only wonder what would have happened if it went on.

Anonymous :freak:


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## Pete McKay (Dec 20, 2006)

'doba, you're going where I'm going with the reverse rotation. When we raced cobalt cars we would test with the magnets flopped every which way to find the best result. You don't get so much of that with neo's but I would imagine even stock magnets may have the best pole arrangements. 

Since we've eliminated the traction magnets we have only a two pole magnetic field. AFX, there is a moment of yaw along the azimuth associated with roll but a physics professor who I'm friends with said you'd need a field reading oscilloscope to measure it. 

The point I was looking for was more of a weight (torque) transfer to the left side of the car with the arm rotating clockwise as opposed to a transfer to the right for an opposite rotating arm. Personally I prefer the initial transfer of that torque (weight) the the inside of the chassis on an oval basically because in real racing that's where teams want it. How much torque in transferred under acceleration, as my professor says, it minimal at best and the advantage is more in the head than on the track.

As far as racing "in the zone" as I call it, when you get into that rhythm, I get that even on small tracks like mine. You're not so much driving by sight really, even though peripheral vision plays a part at Sequoia, more by sound. If you break traction then it can throw off your breaking point. 

As you can tell I don't have a lot of knowledge on the advanced physics but I want to be aware of as much as I can since one of my new racers is an electrical engineering student. I'm sure he's going to keep tech busy.


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## NTxSlotCars (May 27, 2008)

When I get a new car I put it on the track with the wheels raised and run it. Then I flip the car around and run it in the reverse direction. If the RPMs are higher in forward, I leave it alone. If the RPMs are higher in reverse, I flip the motor magnets. Works great with HP7s, 440s and Turbos, not so great with LL, Curve Huggers and SuperG+. Oh yeah, doesn't work on Tjets or Magnatractions either.

Rich


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## SwamperGene (Dec 1, 2003)

NTxSlotCars said:


> When I get a new car I put it on the track with the wheels raised and run it. Then I flip the car around and run it in the reverse direction. If the RPMs are higher in forward, I leave it alone. If the RPMs are higher in reverse, I flip the motor magnets. Works great with HP7s, 440s and Turbos, not so great with LL, Curve Huggers and SuperG+. Oh yeah, doesn't work on Tjets or Magnatractions either.
> 
> Rich


Actually, it works rather well with T-Jets, you just flip one or both upside down, the idea is that you're aligning the strong points of the mag in relationship to each other and the arm timing. You can figure it out prior to assembly with a steel BB, but you still gotta run it to see how it relates to the particular arm.

:thumbsup:


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## AfxToo (Aug 29, 2003)

> a moment of yaw along the azimuth associated with roll


Huh?

http://en.wikipedia.org/wiki/Flight_dynamics


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## NTxSlotCars (May 27, 2008)

OH, I was meaning flip the polarity.

Yaw 'n' Roll

Rich


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## SwamperGene (Dec 1, 2003)

NTxSlotCars said:


> OH, I was meaning flip the polarity.
> 
> Yaw 'n' Roll
> 
> Rich


I knew that, we do it too - left to right, top to bottom- , but it boils down to the same thing, timing. If they're symetrically shaped mags, you can usually accomplish the same thing on a mag car by flipping them top-to-bottom. Back on topic, this works better if you're concerned about which side of the car you want to keep loaded. It all depends on where each mag's "sweet spot" is.


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## Pete McKay (Dec 20, 2006)

AfxToo said:


> Huh?
> 
> http://en.wikipedia.org/wiki/Flight_dynamics


Yeah, I went back and read that again. I blame it on my pain killers.


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## resinmonger (Mar 5, 2008)

Pain killers also kill brain cells but only the weak ones!


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## NTxSlotCars (May 27, 2008)

resinmonger said:


> Pain killers also kill brain cells but only the weak ones!


So does painting slot cars in the cave, man.

It's so easy.

Rich


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## Pete McKay (Dec 20, 2006)

Took me a bit to get that one Rich, I'm really slowing down for some reason, and I don't think it's all the pain killers.

I got the answer I was looking for, it don't matter which way the arm rotates with a stock arm. Chassis torque loading don't make a difference worth worrying about, and there are way too many electrical engineers on this forum.


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## hrnts69 (Apr 12, 2007)

Great info here!

I reversed the rotation of the motor via the motor and traction magnets and worked great in the UTAC race last Sat. nite. Its easly the best handling car i have but no power on the straights. We race Oval only with 1 Road Course race in the season. With the Box Stock 440X2 Pan chassis and reversed motor/traction magnets. I manged to get into the C-Main. Still not as good as my LL M chassis though. That a A-Main car there.

You guys think that the Ohms differ from car to car?

Has anybody tried putting a SG+ or LL M/T motor in the 440X2?
The LL T motor is insanly fast!!!


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