3573 replies to this topic

[idare2bdul]

John said, "...A 2 hole Mura with a 25S is an impressive and brutish beast,.." Perhaps compared to a group 27 but they were a lot more manageable than a 24 or a 23. I used to like running 27/28 double winds which were similar to a 24 1/2 because they were smooth.

Most modern winders can't be bothered with double winds even if you request it. That makes it hard to assess if they would have any current benefit.

[havlicek]

Most programs don't allow, which is why my interest in formal racing is limited!

I think it's both a curse and a blessing Rocky, but I suppose people have had a hard time writing and enforcing a rule set that would limit cost and allow building motors. Then again, the thingie series Jairus runs in seems to do just that.

John said, "...A 2 hole Mura with a 25S is an impressive and brutish beast,.." Perhaps compared to a group 27 but they were a lot more manageable than a 24 or a 23.

Sure thing Mike, but that's why I followed with the qualification regarding Philippe. As badass as a 25S is, it still would survive longer and be more manageable than a 24 or 23. Heck, "even" a 26S can be a real handful.

I used to like running 27/28 double winds which were similar to a 24 1/2 because they were smooth.

Most modern winders can't be bothered with double winds even if you request it. That makes it hard to assess if they would have any current benefit.

I'm coming to see the truth in that Mike. I think doubles might have a place in the mix even today if it weren't a bother and if there were a class that allowed for them as an alternative. I can see that a 27/28 or even a 27D should be a pretty appealing motor with muscle to spare, especially with (as Jeff mentioned recently) modern magnets and setups.

-john

[BoomerDog]

John,

I've got about 6 arms I starting to prep for rewinding. Wires are all off, solder removed, etc. I will coating them with the furnace stuff prior to rewinding and easing the edges of the stack so I can get a nice tight wind. Here's the concern. There is a coating of sorts on these arms from the original manufacturer.....should I strip this stuff off? If so, should it be chemical or sanding or cutting? Or, maybe it really doesn't affect the new winds......your thoughts or anyone else's would be welcome and appreciated. Thanks.....getting closer!

[havlicek]

Excellent Steve! On the question regarding the coating...it depends. I normally strip everything off the arms with a steel wire wheel in the Dremel (watch out for those darned little pieces of wire that fly off and get stuck in your hands, legs, everywhere (yeow!). The reason is two fold, first the cement itself being water based may bead up a little over the common arm coatings so it can help to have a clean and stripped arm. Try a little of the cement with a ch3eap small artist's brush to see how it's going (don't thin it too much...just a little...or the beading-up will get worse). The other reason I clean the old coating off is that the cement is made to bond to metal flue pipe, so I figure it would bond better to an uncoated arm blank. Having said that, the cement really only has to bond well enough to wind over it. When you epoxy the arm, just be sure to get a bit of epoxy on all the places where the cement is exposed but not covered by magnet wire.

1)Get a little extra cement on the sharp edges you eased at the ends of the stack. I do the stack ends last and let a teensy weensy bit hang over that edge for extra protection.

2)Don't worry about getting a little cement on the faces of the stack poles. You can chuck the arm in a Dremel after it's epoxied and give it a quick spin holding some 220 sandpapewr against to clean any cement and epoxy off that got on there. ***Be careful to take into account which way the Dremel spins when playing the sandpaper against the arm so it doesn't grab and pull the sandpaper...you want the paper to "drag" on the arm while holding one end. If it doesn't bet everything off the trailing edges of the arm, just flip it and chuck the other end. Don't do much sanding...just enough to cleanup the arm.

-john

[BoomerDog]

Got it, Captain! Stay tuned......thanks.

[Red Car Driver]

Mr. John Havlicek,

Wondering if you are ready, willing and able to try an HO project motor?????????????? Mabuchi HT 50 "Bamberg" style.

Matthew

[Krash]

For cleaning arms you might want to look at Dremel's #425 Emery wheel...
That's what I have been using, its kind of flexible, not stiff like a cut off wheel.
Don't forget that eye protection.

Dremel # 425

K

[havlicek]

Mr. John Havlicek,

Wondering if you are ready, willing and able to try an HO project motor?????????????? Mabuchi HT 50 "Bamberg" style.

Hi Matthew,

Please call me just "John" If that's one of the little square "can type" motors, I have thought about those as being good candidates. I would have to ask Rick to make me a clamp for my winder and then there's the question of the endbells (as always!). Without getting into all the necessary performance upgrades, I would like to have a whack at rewinding the arm and let others tweak the rest of the motor...unless it became a regular thing. I would also need a couple of them so I could experiment a little. If this is something you're really interested in, I'll ask Rick about a clamp for my crank.

For cleaning arms you might want to look at Dremel's #425 Emery wheel...
That's what I have been using, its kind of flexible, not stiff like a cut off wheel.
Don't forget that eye protection.

Hi Kelley,

I have used several of those in the past as they come in various sizes and shapes. I have even used one for polishing the feed ramp on a .45 acp and they work great. I haven't seen any that are coarse enough to clean heavy coatings like the insulation on arms. They are a cool thing though.


-john

[Robert V.]

Hi guys
I just finished this one FT 16d cleaned up the stacks added the furnace cement, epoxy cut the comm and it's bin rewound as a double 24 turns of 29/30 gauge the timing is advanced in the correct direction i think, this one really screams but runs hot and draws a lot of amps about 4 i had to check the motor on my HO power supply (i need a more powerful supply) no shorts that i can tell but i don't think this one would live very long in a car but it might make a good drag motor.

[havlicek]

Excellent Bob! 24 turns of 29/30 sounds a little on the light side, and it looks like the timing is way advanced...hard to tell but maybe somewhere around 40 degrees from the picture??? I will do doubles using #29 wire of anywhere from 20-24 turns, but with less advanced timing that run warm alright (especially when they're down around 20turns ), but they're not flame throwers and come in around .2 to .3 ohm I think. Light gauge wire is a good test of the furnace cement as well because it's much easier to damage and short than the heavier stuff. Nice job!

-john

[Alchemist]

Hi Robert,

Very nice job! You're getting better each time I see a new picture!!! If I may ask you please, I see powder near the comm area, is that from having turned the comm? What type of equipment did you use to turn the comm please?

Again, it looks real nice Robert - more pix please?

Thank you!

Ernie

p.s. Happy Easter everyone!!

[havlicek]

Speaking of doubles, I just finished off a #29 double at the low end of the spectrum @ .2 ohm on a vintage Mura blank with a recycled Mura com and a new drill blank shaft...all for a Blogger that wanted "nothing fancy, an FT16D". I was barely able to balance this one and quickly got to the point where I had to leave it alone as I couldn't find any more imbalance (even with razor blades and static balancing, this rarely happens):


For the setup, I chose a can that was in sore need of some TLC and replaced the caged bushing with a new soldered-in 2x6 Mura bushing. After stripping it, drilling it for screws and cleaning/repainting it Czechoslovakian purple^TM , I installed a set of Arco magnets and turned my attention to the endbell. This was a bare Tradeship endbell and I first popped on a set of spring post protectors and then set out to install some 36D brush hardware. This time I had at it a little differently by first opening up the v-grooves a bit for the larger brush tubes/heatsinks. I then ground the tops of the brush tubes flat to mate with the flat FT16D hoods and tinned both the hoods and the tubes. Then using a brush alignment tool and a spare shaft, I put the whole thing together and heated the solder to fix the tubes to the hoods and slightly form the endbell below the brush tubes. I then removed the tubes with the hoods and placed a teensy bit of hi-temp epoxy underneath them and popped the whole thing into the easy bake oven to cure. The hoods are solidly attached to the brush tubes and the whole shebang is sitting nice and square on the endbell. The motor sounds aces and is definitely on the high edge for a Mabuchi, but doesn't seem stooooopid.



-john

[Robert V.]

Thanks Ernie thanks John, the powder look near the comm next to the tabs may be very tiny air bubbles in the epoxy i am still learning how to properly cure it, I used a comm lathe made by Integy yes John i agree i may have advanced the timing to far next time i will just go a hair past neutral but it does run decent, when i finish the motor i will post a new pic, that motor looks great John it's amazing how little amperage draw you get with your motors it appears i still have a lot to learn.

[Phil Irvin]

ROBERT,

NICELY DONE!.
Like John says...Too much advance..BUT Try it. Just mite not get THAT hot. It mite be good for a 10 lap, quick run. Try and find a good timing guage. It will come in handy. Try advancing about half way to the T, or less, edge of the laminations. That will give you about 25 degrees. If you look at a death star. That is supposed to be 20-25 deg. Usually closer to 20.

OLPHRT
PHIL I.

[havlicek]

that motor looks great John it's amazing how little amperage draw you get with your motors it appears i still have a lot to learn.

Thanks Robert, but many of my motors are real amp-suckers. It's just that I try and moderate things when I'm doing Mabuchis now, and that's why I've been using double winds for them lately. I'm presently without a power supply, so I haven't been able to take amp readings, but I think the double above is drawing a healthy amount of current. There's no free lunch with the laws of physics, so I think the best you can do is try and tune everything to run smoothly because inefficiencies will show up as increased current draw and heat. Nice tight-fitting bushings or bearings, a true com, very little endplay, broken-in brushes and as good a balance job as you can manage will all up to a much better running motor. You did a fine job. The wind looks nice and neat and doubles are much more troublesome than singles, so bravo!

-john

[Robert V.]

Thanks Phil yes next time i will use less advance that should help a little, i am not going to tear the arm apart because it does run pretty good i will break in the brushes and see what happens. Thanks John i agree good tuning should help with current draw it does make sense.

[Champion 507]

Robert,

Drag slot car racing is very popular now. With that arm properly set up in motor, it should propel even a poorly set up drag car down a full length drag strip in about a second or less, so heat shouldn't be a problem. However I've seen many Chinese comms not wanting to put up with those kinds of rpm's and found their way out thru the endbells. As Ronny & the Daytonas put it so well in their 1960's song "Little GTO"..."turn it on, wind it up, blow it out..."

[idare2bdul]

Arms all die eventually, some from old age others with more entertainment value.

It's better than ending up in a landfill not having been run.

[Champion 507]

QUOTE:
Arms all die eventually, some from old age others with more entertainment value.

It's better than ending up in a landfill not having been run.
_________________________________________________________________________________________________________________________

Amen, Mike. Well said!

[Slotgeezer]

Great work, as usual, on the armature, John...

Plus, the 'how-to' on the endbell & the hardware was VERY informative... I liked reading about heating the whole she-bang up to flow the solder, & then adding the epoxy... Very creative!...

Really liked Bob's idea w/ the 29/30 double, you only need one spool of each, & it'll be a real zippy wind!... I remember Thorp used to wind 28/29's, so using wire sizes one size up/down was common, back then...

Great looking color, on the can... I assume it has late-production D-can magnets, for that wind... Bet the lucky fella will enjoy it! ... I see ' thingie ' written all over it! ... Take care!


Jeff Easterly

[havlicek]

Hi Jeff,

Thanks for the look and adding the bits of history. Yes, I've seen quite a bunch of vintage doubles...27/28, 28/28, 28/29 while doing restorations for bloggers and the 28/29 seems to be the most frequent followed by the 28/28. I'm surprised that such hot winds were used with Mabuchi setups back then and presumably for racing too! I like the Czechoslovakian Purple^TM also, boith because of the way it looks, but also because it seems to cure nice and hard. This motor got a pair of slightly beat-up Arcos. They had some chipping and whatnot on them, but measured fine on my meter. I'm sure that the wind could use something a bit stronger still, but guess that the combination of the Arcos and the 29 double was around back then???

-john

[DirtyHairy]

i seen the post and got to looking....i think thats MY motor,,,,or John really likes that purple.....and if that is MY motor ,,,you are correct Jeff,,,it is destined for a thingie....hope to post some pics soon

[Mr. Frank]

i seen the post and got to looking....i think thats MY motor,,,,or John really likes that purple.....and if that is MY motor ,,,you are correct Jeff,,,it is destined for a thingie....hope to post some pics soon

Justin; Do you realy think you will EVER get a thingie completed, you know, with all that veido game playing you do, herd about that last night from your wife. You know the sunchasers will be here soon, and I don't think you can run your own car.



The old man... Mr. Frank

[Prof. Fate]

Hi

John, in the day, we usually tried to calculate a motor that would survive just the race and not a minute longer! These days running this stuff for fun, it is annoying to need to rebuild a motor everytime you run it.

I just lost a Pcan arm playing around and knowing what it takes to build the thing, I am a little annoyed.

Fate

[DirtyHairy]

Dont worry OLDMAN this "THingie" will do John's awesome motor proud,,,,,i wont be surprised if you try and copy my idea