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#1 brnursebmt

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Posted 20 August 2014 - 09:51 AM

After getting my butt handed to me last Saturday at the Retro South race I finally had the courage to go into my slot car room today and take a look at my JUNK slot cars that I tried to compete with at the race. Now this is the first time I had ever ran the JK Retro Hawk motors. My cars sucked entirely and now I think I know why. I had broken the motors in for about ten minutes each before I installed them in the cars before I left. Every car was soooo much slower than the rest of the field in each class.
 
So I'm looking at the motors this morning thinking maybe they take longer to break in or something. I look inside the motors with a strong lens and light and I see that the brushes are installed 90 degrees out! Meaning that the manufactured radius of the brush is rotated 90 degrees from the radius of the comm. I had two thin dark brush marks on each of the comms where the outer edge of the brushes were all that was touching the comm! No damn wonder they were slow! They would have NEVER broken in! 

Has anybody seen this? I know these are cheap motors but I think I deserve a refund or something!!
Bobby Robinson RN

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#2 Bernie

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Posted 20 August 2014 - 09:55 AM

Nothing new here, Bobby. The Hawk 7 as well as the Retro Hawk have brushes intalled like this. They need to be broken in until they seat properly.

Seems to me that after running a complete race they should have broken in by now. Just run them at 3v until they seat. There are numerous threads on SB that discussed this for the last year or so.
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#3 brnursebmt

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Posted 20 August 2014 - 10:13 AM

You would think so, Bernie. But not so. These brushes are still far from seated. As I said, this is my first time to race these motors. Guess I'm just out of the loop concerning them.
Bobby Robinson RN

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#4 Bill from NH

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Posted 20 August 2014 - 10:27 AM

It's not just JK Hawks, although they may have harder brushes that last longer. The brushes on all FK motors are oriented like this. Check a new Falcon or TSR motor.


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#5 brnursebmt

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Posted 20 August 2014 - 10:36 AM

Wow.
Bobby Robinson RN

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#6 tonyp

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Posted 20 August 2014 - 10:45 AM

They take hours to break in.


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#7 Cap Henry

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Posted 20 August 2014 - 10:51 AM

Break in takes awhile. At last years Sano I broke David Krumnow's motor in for an hour, then he ran it in all three classes, recording one win and two other podiums. 
 
A ten minute break in probably didn't do much. LOL, Also, you guys were on a pretty fast King; did you have hard enough tires on? Soft tires will make any motor appear slow vs a car on harder tires.

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#8 Danny Zona

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Posted 20 August 2014 - 11:15 AM

I've been breaking them in at 3v for an hour then another 30 minutes at 5v. Some racers I know break them in for two hours.
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#9 brnursebmt

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Posted 20 August 2014 - 11:17 AM

But here is the real question, why are the brushes installed this way? 

In response to Bill's post, I never had this problem with Falcons or TSR motors. I always ran the motor until it got hot, spray cleaned it and reoiled and the motor was fast. Always.
Bobby Robinson RN

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#10 Tex

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Posted 20 August 2014 - 11:21 AM

How many times have we ALL had to relearn lessons we thought we'd already learned? NEVER ASSUME ANYTHING! You assumed breaking them in for 10 minutes was sufficient and you obviously didn't check them once you thought they were broken in. A quick look-see at the comm before installing the motors might have yielded different race results... would've been five seconds well spent. Been there, done that. And I'm sure I'll be there again sometime. :wacko2: 

We make all kinds of assumptions and don't check things ahead of time as a result. Don't assume tech tools are 100% spot on. Use your calipers to check them for accuracy; fix if possible. Doing so might prevent you from being turned back at the tech bench with only five minutes to go before tech closes.

Don't assume the tire truer calibration adjustment thingie is spot on either. Check its accuracy by setting it up for whatever diameter you are looking for, true the tires down, but THEN check them with calipers. Again, doing so may prevent you from being told your tires are undersized when you just got through truing them up... wasted $ on a new set of tires AND tech closes in five minutes.

Manufactured guide tongues... do they REALLY hold the guide flag level? Check for level from both the side AND front; adjust if necessary.

Motor brackets... is the motor 100% dead-center? I've had some that are off-center by 10-thou or so; so, would you center up the motor or center up the bracket when building the chassis?

Don't assume ANYthing. Look ahead. An ounce of prevention is worth a pound of cure.

But here is the real question,  why are the brushes installed this way?

 
It's irrelevant "why". They just "are". Don't waste time/energy being frustrated by not understanding "why"; whether you understand "why" or not isn't going to change anything.

Accept it. Deal with it appropriately (longer break-in period). Move on to the next hurdle. :)
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#11 ejgehrken

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Posted 20 August 2014 - 11:45 AM

I run all my hawks in cars until they are running competitively, then I set them aside for an upcoming race. These motors need a load on them in order to break in. Running them on the power supply simply does not do the trick.


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#12 John C Martin

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Posted 20 August 2014 - 12:15 PM

Bobby my Retro hawk at that race, in stockcar was broken in 3 volts for@ 30 seconds in WATER..still was not enough, I'm going for 1 min. Next..motor really came alive about the second heat ,much faster than what it qual..
The water keeps the com. much cleaner..
Main problem I've seen with these motors is the com slots filling with brush deposits. So you need to flush them out good with cleaner,after breakin..
I did run 9/27 in stockcar ,,I know Will ran a 10/29 in F1 he was very fast...

#13 brnursebmt

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Posted 20 August 2014 - 12:33 PM

I've believed in the water break in for many years but have never done it with the FK style motors.
Bobby Robinson RN

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#14 MSwiss

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Posted 20 August 2014 - 12:33 PM

What John says confirms what Eric said.

If you have the luxury of breaking them in under load, it's probably better.

To answer Bobby's question, "Why are they oriented that way?

The Chinese motor companies have been asked that question and I don't think they have ever given a real technical answer other than, "It's better that way".

Bobby, comparing how you broke in your TSRs and F7s (which both also have the brushes the wrong way as Bill mentioned) doesn't apply.

The Retro Hawk obviously has a much harder brush compound.

You can't realistically expect an FK motor that lasts three or four times longer to break in as quickly.

I've heard a pretty credible rumor that F7 prototypes were made with the brushes oriented "correctly" and they tested out to be no better, or inferior.

Ironically, that time wasted trying to improve F7 brush life probably helped open the door for the Hawk Retro.
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#15 Bryan Warmack

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Posted 20 August 2014 - 12:39 PM

But here is the real question, why are the brushes installed this way? In response to Bill's post, I never had this problem with Falcons or TSR motors. I always ran the motor until it got hot, spray cleaned it and reoiled and the motor was fast. Always.


Bobby,

From what I've been told the alignment of the brushes is done this way intentionally to reduce the possibility of chipping a brush when first running. Makes sense.
 
Out here on the West Coast at Buena Park Raceway we have been testing the Retro Hawks for several months now and they definitely require more of a break-in period than the TSRs or Falcons. We are trying ALL KINDS of creative procedures to seat the brushes but oddly enough though, perhaps the fastest Hawk I have seen wasn't broken in at all. The racer said he just put it in a car and ran it in a race. Then he ran it in another race. When he ran it on our King track for its third race it just seemed to me to be exceptionally quick. When I check it out after the race the brushes were still leaving TWO DISTINCT tracks on the comm as the brushes were still not completely seated!...??? I think it might be a good motor!! :laugh2:
 
Probably in October, the SCRRA plans to have a King track race which will involve the use of ONE hand-out Retro Hawk motor purchased from the raceway the day of the race. Everyone breaks their motor in as they wish and it will be used for both F1 AND Can-Am that day. Obviously, if a motor throws a wind or something a replacement will be allowed but basically the idea is... ONE motor, with a short break in period, being used to run both races... Should be interesting and the SCRRA will announce the details shortly. :)
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#16 tonyp

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Posted 20 August 2014 - 12:45 PM

I think the brush alignment is a Mabuchi thing. Back in the early days of R/C the Mabuchi motors always had the brushes 90 degrees off. The Retro Hawks I have had good luck with running at 3 amps for four hours. I just hook them up and forget them.
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#17 MSwiss

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Posted 20 August 2014 - 12:49 PM

Bryan,

Thanks for the great info.

Chipping? Sounds sort of like why "normal" brushes come with little flats on the end.

Your one motor race concept sound real cool.

PS: while I don't race that much I've had RHs that were pretty fast early on. The prototype certainly was, not to say it didn't get a bit faster after 24+ minutes of track time.

Mike Swiss
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#18 A. J. Hoyt

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Posted 20 August 2014 - 12:55 PM

I have always broken my FK motors in on the track. I run a about 30-35 laps on the track never going past half throttle - this is still under load. (Make sure you let everyone know that you are breaking in a motor so you are not a hazard - I also scuff in / on-car true a new set of tires during this time.)
 
I check the temperature of the motor right afterwards; if it is too hot to hold a finger on it, it will likely be a hot running motor. There comes a time during the half-throttle break-in where the motor suddenly "frees up" and it becomes a bunch faster in top end and punch off the corner. Then, I let it cool completely (at least fifteen minutes).
 
I, generally, will run it in the upcoming race. In the first or second heat it usually comes alive and just keeps getting faster in each race after that.
 
Don't give up on a JK Retro Hawk because it is not fast in the first race. I had two (of my first ten) that were not fast after the first race and my rolling drum dyno supported this.
 
We opened up our Falcon Wing class to JK Retro Hawks because it was very rare for ANYONE to get a second race out of the new generation Falcon 7s (some have died in the first heat of the first race, lots have thrown wires right off the poles) so I "committed" these two motors to be soldered in a stamped steel chassis. They were mediocre at first but were VERY fast by the end of the race in the Falcon Wing class. There is no question that the "under load" on-track break-in in the Wing car class is different from the heavier Retro cars, but they are both VERY fast and are the top performers of all of the JK Retro Hawk motors on the dyno. I imagine they would be SUPER Retro motors but I am afraid of the heat put in to un-solder them now.
 
I have been getting seven races and counting on my better JK Retro Hawks in Can-Am cars and they just keep getting faster (on track and dyno) with LOTS of motor brush left. I have not found the fall-off point yet.
 
Moral of the story - don't give up on those "slower" JK Retro Hawk motors yet - give them a chance. I begged someone (anyone) to run my Twistamon chassis in our latest Saturday night race just to put a break-in race on the motor - I had no takers! I put the car on the track and, on the third lap, it was a half a tenth faster than anyone else's fast time during that race. This "less-than" motor gave a second life to my "Twistamon" car.
 
I installed a JK Retro Hawk into my top Stock Car gearing it 8/26 (Can-Ams are 9/28) following two spectacular PS4002 smoking failures. I applied a whole race of break-in at 3v (the race was the Nationwide Mid-Ohio race - essentially several hours). I broke it in on track at half throttle and it came around during our RMRRA race - it was fast enough to win it. The post-race dyno numbers were exceptionally, good corrected for gear ratio.
 
I am a fan of the JK Retro Hawk. I think they are the best new item since I started racing Retro.
 
Keep it in the slot (please, please, please!),
 
AJ

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#19 Pablo

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Posted 20 August 2014 - 02:54 PM

Bobby,

"You need to get out more often". Every FK type motor ever made AFAIK has this type brush arrangement.  ^_^
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#20 brnursebmt

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Posted 20 August 2014 - 03:44 PM

Yes, Pablo. You are correct, sir. Been caught up in the Pro Slot motor haze for too long.
Bobby Robinson RN

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#21 JerseyJohn

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Posted 20 August 2014 - 03:55 PM

FYi it's very important to flush them out after break in. I also us canned air with a nozzle to clean out the comm slots.
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#22 redbackspyder

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Posted 20 August 2014 - 03:59 PM

May I ask a stupid question: How does the motor know if it is being broken-in, in water, or dry on a power supply... After the motor is cleaned out and re-oiled, how can it tell which way it was broken-in?   
 
The reason I ask is, many people claim that one way or another is superior, I just wonder how the motor knows?  

Thanks,

Mill

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#23 Pablo

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Posted 20 August 2014 - 04:09 PM

Yes, Pablo. You are correct, sir. Been caught up in the Pro Slot motor haze for too long.


Thanks for not taking it the wrong way, Bobby. :)  I'm a speed reader, so for me it's easy to stay on top of this stuff. You should be applauded for not "sleeping under the Slotblog track" like I do. :laugh2:
 
Do a Slotblog search "brush orientation" and start reading... you might want to drink a big strong cup of coffee first. :wacko2:
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#24 tonyp

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Posted 20 August 2014 - 04:20 PM

Motor is stupid. It only knows what you tell it. Slot motor black science is based on old wives tales.

Water just allows the brushes to break-in faster. That's it. Old R/C trick from the '80s when we used hand-out Igrashi motors with concrete brushes.
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#25 redbackspyder

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Posted 20 August 2014 - 04:45 PM

Tony,

Thanks, because so many people lately have said, "You can't break a Retro Hawk in water", and it just seemed to me that the motor could not know, unless somehow those hard brushes could infuse water into them... 
 
Just like the Monty Ohren break-in, where he finishes with the 30 seconds of naphtha, how does that make a difference over time, once the brushes wear in? How could that make any kind of long-lasting difference, whereas he claimed the difference between it and dry break in was .1 sec?
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