58 replies to this topic

[CoastalAngler1]

I am needing to build up a stable of motors for JK Flexi racing: Retro Hawks and hawk 7s.  Got a few questions... and likely there are questions I've not thought of. 
 
How do you get fast motors?
Is there a way to tell the fast ones after purchase and break-in, aside from installing and measuring lap times?
Zapping worth the $2 ouch fee?
Break-in secrets?
Gearing secrets?

[slotcarone]

The Retro Hawks seem to only break in on the track. At least 30 minutes of run time. Just hammer it after 15 minutes on a power supply.

[Samiam]

Forget about the $2 zap. Unless it is a zapper capable of zapping cobalts it is useless on Poly-Neos. Any gains in readings are most likely the magnetizing of the can only. Ken-   claims he has "perfected" the procedure though.    

 

I break mine in on 3 volts for 30-40 min then run 'em on the track like Mike suggests.

[havlicek]

 How do you get fast motors?

 
... well, that IS the question.
 

Is there a way to tell the fast ones after purchase and break-in, aside from installing and measuring lap times?

 
No.

 

Zapping worth the $2 ouch fee?

 

No... it wouldn't be worth 50 cents if that were the cost.

 

Break-in secrets?

 

Like the guys above said... and therefore they aren't secrets!
 

Gearing secrets? 

 

That one's going to be track-dependent, so whatever seems to be working at your home track will be the best answer.
 
-john

[DOCinCanton]

Charlie, I answered your PM. Specifically for the JK Retro Hawk, I brake the motor in for at least 3 hours at 3.5V.  Also, I know for a fact that Bill's zapper works on Retro Hawk motors, definitely a positive influence; pardon the pun.

[Big Booty]

The magical breakin has always intrigued me.  All you are doing is matching the curvature of the comm to the brushes and perhaps wearing in the bearings a little.  If theres more to it than that Id like to know what it is?

 

As far as picking a "fast" motor there are lots of optical tachos on evilbay for about $20-30 dollars to measure rpm and you can build a fairly simple torque rig with a set of digital scales.  I then multiply max rpm by stall torque to give me a number.  The bigger the number the better.

 

Gearing, just choose a ratio that you think is close, do some laps and record the times and then change 2 teeth up and down on the spur and repeat.  It will soon tell you which direction to head in.   

 

Magnet zapping may provide an improvement if the magnets are too weak for the arm.  If they are already too strong for the arm zapping them to get more magnetic strength out of them may actually hurt performance.  I make these comments based on my testing deathstar motors.

[CoastalAngler1]

Terry Tawney showed me his retro hawk motor program box once.  I wish I could go shopping there...  Terry says 4.0 volts in a glass of distilled water for 10 seconds pre-oiled, dry off, then run like heck on the track like Mr Katz says.  I used my 3v dual 'D' battery procedure for 15 seconds in a glass of st johns river water on this one.  

 

Doc - I've had good luck with Bill's zaps too!   

 

What about track power?  Do you guys change motors a bunch of times, or set up many cars to test?

[havlicek]

Magnet zapping may provide an improvement if the magnets are too weak for the arm.  If they are already too strong for the arm zapping them to get more magnetic strength out of them may actually hurt performance.  I make these comments based on my testing deathstar motors.

 

The "deathstars" use ceramics, these use neos... apples and oranges. Degrading the field strength of neos by zapping them with a typical ceramic zapper, could result in more RPMs and less torque.
 
-john

[Gator Bob]

Zap it 'backards' and go down a tooth? ... Oops

[Big Booty]

A magnetic field strength of "X" Tesla is still "X" Tesla regardless of the magnet material composition.  And yes generally speaking less B field strength (mag strength) results in more rpm but at the cost of torque.  The trade off between rpm and torque are related to each other but not strictly on a one to one basis.  That is doubling one does not necessarily half the other.   There are gains to be had by slightly altering the B field for a given armature.  I tinker with the B field (mag strength) until I get a maximum in rpm x stall torque.   

[DOCinCanton]

Bill Pinch has an old school zapper.

[havlicek]

A magnetic field strength of "X" Tesla is still "X" Tesla regardless of the magnet material composition.  And yes generally speaking less B field strength (mag strength) results in more rpm but at the cost of torque.  The trade off between rpm and torque are related to each other but not strictly on a one to one basis.  That is doubling one does not necessarily half the other.   There are gains to be had by slightly altering the B field for a given armature.  I tinker with the B field (mag strength) until I get a maximum in rpm x stall torque.   

 

All basic, but the only relevant issue here is whether tests done by zapping ceramics will follow when *trying* to zap neos. Very few people outside of industry have access to... much less own a zapper capable of fully charging/reversing neos... even the polymer matrix ones, let alone the "solid" neos. It's generally not a good idea to try this, unless you're willing to throw magnets away. In the case of sealed motors, you would be throwing motors away.

 

-john

[Gator Bob]

  I tinker with the B field (mag strength) until I get a maximum in rpm x stall torque.   

 

How do you make those adjustments?

[Big Booty]

Oh I can see how we got onto magnet zapping now..... sorry Im a bit slow. Im a lot less high tech than magnet zapping.  I just play with the air gap by shimming to reduce the gap or by wet-rubbing with emery paper the surface of the mag to increase the air gap.  Im assuming the Retro hawk or hawk 7 is a sealed motor class?  So not being able to open up the can would stop you from doing such things.  Still nothing stopping you from some simple trial and error measurements on a donor motor to see whether the mags are too strong  or too weak for the arm or indeed just right.  How to use that knowledge on a sealed motor though??  Dont really know?  I can see where John was going now with all the zapping stuff.  I suppose if you find that the magnets are too strong you could try increasing the "external" air gap by opening up the vent holes?  Or maybe go more extreme and grind away the outside of the can on each side that holds the magnets in place.  That would increase the magnetic reluctance of the magnetic circuit.  Would that constitute opening the sealed motor?  Dont know, you'd have to read the rules under which you race very carefully.  Or you could try what John was suggesting and try an de-zap the magnets?  No idea if this would work.

[Big Booty]

Oh I just thought of something....have no idea whether this would work or not.  What if you were to place small button neos or maybe ceramics along the outer edges of the can on both sides so that the overall height of the external magnets is less then the height of the can?  This would increase the rpm but i have no idea how much you would kill the torque?  Cant see how this would be deemed opening the can on a sealed motor.  Unless there are rules covering the addition of external magnets.  Let me stress that i have no idea if this would actually work, just spit balling an idea that popped into my head.

[Samiam]

Sorry Rick. That would be illegal in every set of race rules I've seen. 

 

"just spit balling an idea that popped into my head."

 

 

Let it pop back out.

[Michael Rigsby]

Charlie,

 

I will give you the experience of someone who originally recommended the Retro Hawk for approval in My Series NASCAR after comparing them to the Falcon VII, and the hot shoes at our track mostly run the Retro Hawk because it is reliable and will give you a lot of racing and practicing for only $13.

 

We have tried breaking these motors in using water, alcohol, and whatever, and nothing beats just a normal power supply breakin and running like the devil on the track. I was drying out motors for guys at the enduro at Jacksonville, and broke in a couple in water for local racers.  It still took about 100 laps of racing for the motor to come in on those given the water treatment.  Judge for yourself.  I don't waste my time anymore doing it.  I have a MuchMore Motor Master, an older RC break in box, that cycles the motor from 2 volts to 8 volts constantly. I set it up for three 25 minute cycles doing that, put it in the car, and run it normally.  It works for me.  Water break in is a total waste of time with these motors and the brushes they have. Water doesn't phase them like it did an older Falcon VII.

 

An old school zapper like a Carlisle like Bill P., has MAY help if the magnets get weak. I do not recommend zapping them before putting the motor in the car.  The trick on these motors is to use as little heat as possible soldering it in, and not overgearing the car to get speed.  Killing the magnets with excessive heat is more of a danger than anything else.   Maybe after about four races and provided there was enough brush left, I might zap it in a large commercial zapper.  Don't waste your time with a Bow zapper like I have, or any of the other small portable zappers, they WILL NOT WORK on these motors. Like John said above, you may kill one of these Neo magnet motors trying to zap it because of the special equipment required to do it.

 

The best way to pick a fast motor, is to grab the first one off the wall at the raceway, purchase it, break it in, and put it in the car and run it.  I have found these motors to be pretty dang equal, with only about a tenth between my worst and my best. The biggest difference seems to be in the amount of brakes that the motor has from motor to motor.  I have three NASCAR's set up with the Retro Hawk, all run in the 4.3-4.4 time area on our track, and the brakes are different between all the motors. TRACK TIME IS YOUR BEST RATING ON THE MOTOR....PERIOD. Motors may seem strong in RPM when free revving them, but there is a torque factor there you can't really measure without seeing how the motor performs in the car. I still have my original Retro Hawk I purchased from when it arrived last year.  It was turning 4.3's in my NASCAR when I pulled it out of the car, but the brakes were going away making it hard to brake for the deadman on the hillclimb in racing.  At my last calculation, it has about 1800-1900 laps of practice and racing.

 

Gearing...well...another story and another ball of fuzz to deal with.  On our hillclimb, and the guys who race at Bills track from our area, run either a 12/34 or 12/35 with these motors running a .720-.730 rear tire.  I have two geared at 12/34, and one at 12/35 to get a little more brake and flatter exit response out of the donut into the leadon.  All of the motors run pretty cool at 13.8V track voltage and our hillclimb has two 90 amp power supplies with a large cap so it stays steady. 

 

I do not recommend cutting the shaft unless you have to.  I know some cut it when using in a flexi, but I kind of like have that little extra length on the shaft to act as a heat sink, even as small as it is.  You can only do this if you do not run a comm cooler...no room on a flexi.

 

As far as the Hawk 7, I was a big proponent for them when they came out, and highly recommended them for Group F wing car and GTP for amateur classes, but when we started having them throw winds, I switch to the Hawk 6 and didn't look back.

 

These are just my opinions, and from a guy who takes notes on all my motors and performance specs, racing or not.

 

Good Luck with your program.

[CoastalAngler1]

New Hawk 6's come with tied comms - is that OK?

 

From the MYSeries.org - 2015 Rules:

JK LMP
Motor
JK Hawk 7 or JK Hawk Retro – Must not have been opened or tampered with in any way.
JK Hawk 6 – Legal motor setup is the JK Hawk 6 from #30306 only
Replacement Armature – JK Hawk 6 (#303062) only. No wrapped commutators
No modifications allowed except:
May change can screws
May true commutator
May zap magnets and glue magnets in place
May change motor brushes and springs

[Big Booty]

The hawk 6 is the only motor with external brushes?  It states that you can change the brushes and springs.  It doesn't stipulate what brushes and springs can be used so you have room to experiment there.  Measure the diameter of the comm and then the height of the brushes.  My guess is that the brush height will be too tall for the comm.  Undercut the trailing edge of the brushes an see if that improves things.  Also lower powered motors tend to run too much spring tension.  Reduce the tension and see if that improves things.

 

Good luck.

[DOCinCanton]

Charlie, I have no secrets for you, just good common sense. Basically, to get a good Hawk 6 motor, it's paying attension to details. I am not an expert on building fast motors but the following is on my common sense list.

 

1) Alignment of the bushings. Its probably a good idea to cement the endbell bushing in place; it backs out way too easy and may become sloppy in its fit to the endbell. It's probably a good idea to replace the can bushing. The stock brushing will wear out the arm shaft. Lots of steel in it. When doing this, get on old arm and wrap some tape around it so that when you push it into the can, the arm is snug. (or buy a properly sized setup arm) Align the can bushing by opening it's hole a tad and solder in place with the snug arm and the endbell in place.

 

2) True the commutator. If the motor has been used (or even a new arm) you must clean up all of the dark/worn spots on the comm.

 

2.5) I added this after posting: Align the brush hoods. The stock brush hoods are terrible. You can spend alot of time here, but it's worth it. Buy an alignment tool for this purpose. Also, use a small square file to smooth out the sharp edges.

 

3) With the screws installed in the endbell, make sure the arm spins free centered in the magnetic field. Use arm spacings at either end to achieve this. Arm slop: as little as possible. Buy .003" and .006' arm spacers. Use as accordingly.

 

4) Brushes: This is maybe the single most important thing about a fast Hawk 6 motor. The brushes should be prepped to match the radius of the comm. The Chinese comm is a lot smaller in OD than the American comm. I finish up with something like 1200 grit sand paper wrapped around the shank of a properly sized drill bit. I have build really fast motors with the stock Hawk 6 brushes, Goldust brushes, and Big Foot IIs.

 

5) Springs: Again here, I have built very fast Hawk 6 motors using the stock Hawk 6 springs, Champion red springs, and Koford 313s.

 

6) Seating the motor brushes: I can not say enough about this matter. It's critical. Once you are ready to break the motor in, use only about 3.2v. With low light, only a very small amount of spark should be present. If there is a lot of sparking, shut down immediately and investigate the matter. If little sparking, check for high heat in about 3 minutes. I can't tell you whats too hot. If you can't hold the motor comfortably, then it's probably too hot, shut down. I have had to break in a motor one time in 5 minute cycles, running about 10 cycles. 5 minutes on, 5 minutes off.

 

See, no secrets, just common sense and paying attention to details. Building a fast Hawk 6 motor can be very time consuming and sometimes very fustrating.

[Michael Rigsby]

If you got a Hawk 6 with a factory tied comm, it must be a very latest shipment. I have two new ones and just checked and neither has a tied comm.  If they are coming now with tied comms, that is something that will have to be addressed by the rules committee because as far as I know they are sticking to the no tied comms rule to keep people from letting Alpha sell them regular Hawk arms he modifies and ties the comm on. I have been specifying when I sent arms to Alpha for him NOT to tie the comm in his refurb process, that way I'm legal. 

 

Doc posted great advice on the Hawk 6. Key word is patience... and more patience... and don't rush. Treat it like you are working on restoring a masterpiece... and  you will be rewarded.

[CoastalAngler1]

Thanks, Doc!!  

 

Gator Bob did all the above to my Hawk 6 that is running in LMP Saturday, he even gave it a name - 'Alf' is engraved on it - its pretty fast.  

Also, I do have an alignment tool and brush radius tool and arm slugs, and arm spacers, and BF11s, and Champion red springs...

I got skillz to blueprint those motors, thanks to Pablo!

 

I can't wait to check out your pit and cars -  

 

 Doc is the 2014 Florida My Series Grand Champion - congrats again! 

[DOCinCanton]

I have something to add to post #20. For the brushes, the break in process should end up with the brushes completely seated on the comm. So after running the brushes in for about 30 minutes, stop, and pull out each brush. Inspect the surface that runs on the comm. It should be nice and shiny with no rounded off corners from the prepping work that you did.

 

A tip from Terry is to inscribe two dots on top of one brush and one dot on the other. Do this on all motor builds in a consistent manner. When you remove a motor brush for inspection (and drop it or not) you will know which way it goes back in. Inscribe with an Xacto blade.

 

My system is to put two dots on the top surface of the brush that faces toward the rear axle, and one dot on the brush that faces the front axle.

 

Another small note: I always like the positive terminal of the motor to be closer to the front axle. For the Hawk 6, I rotate the endbell on the can 180 degrees and then switch the red and black pieces of the endbell hardware. (The magnet with the white mark goes against the rear axle)

[Bill from NH]

Doc, I don't run Hawk 6 motors, but I do like your "common sense" approach to motor building. This approach would apply when building most any can motor. I've always scribed motor brushes with a "R" & a "L" on their outward faces. Also, I zap my motors so my leadwire runs straight rather than crossed. Three RJR hemi-wound arms would be the only exception. While I didn't learn gobs of new stuff, I did appreciate your posts enough to save them as a Word document. Thanks!

[Danny Zona]

I know Doc has a couple secrets he is holding back with the rocket motors he has. Ha-ha.