3573 replies to this topic

[HarV Wallbanger III]

John sorry your meter crapped out. The guy that did my Front Line ones back in the 80's died last year and his wife can not find the paperwork on them to give me... I'm looking for a used one now for you.

[wbugenis]

John,

The meter you have is now sold as a BK Precision 1095B. Maybe they can do a repair.

I am off to the ISRA Worlds in Brazil this evening with a bunch of untested (due to the flood) Havlicec wound eurosport motors.

Bill

[havlicek]

Hi Barney,

Yeah, it's almost funny because for the first couple of years I started winding again, I was fine using a regular multimeter thinkiung it wasn't THAT important. Now I feel like I'm working blind after having gotten used to being able to "really" test the arms Hey Bill...GOOD LUCK in Brazil at the ISRA Worlds...after the flood, you could use some fun I bet! Safe trip!

-john

[havlicek]

Here's the pictures of Ernie's two Hawks. Of the two, I like the #27 best (in front). It draws a bit more current, but runs a lot faster. To get the most out of these things, i could experiment for days and use a dozen arms or more before I probably got a formula together. As it is though, these both are a good start



-john

[Marty N]

Maybe this will help John on those Emo motors. I've spent some serious time with those 65/30 arms you wound form me plus an Alpha and a few stock Hawks. My Emo setups are shimmed down to .55* and all arms are .513 diameter. Only the timing varies. 22*, 25* and 30*. Bill's coms on some, Hawk coms on others. I got to a point in dyno and track testing where I settled on this gap and arm diameter. Then I starting swapping these arms into this one set up and what I found out me a bit. I know why but don't want to turn this into a book.

All three timings produced the same trace!! Same peak RPM, same torque, same rates of accelleration...the difference was only this. The high timed arms drew more current and ran hotter. 10 amps on the dyno at peak rpm for the 22* arm and 17 amps for the 30* arm under the same conditions. The lower the timing the cooler she ran. In ceramic motors eveyone knows, more timing, more rpm. less torque, right? Depends but that's another story.

Oddly the 22* arm has been the quickest in the car but by less than normal data scatter.

Point is..timing is key to these beast. Keep it lowwwwwww. I know, road race is different, motors run longer and it's more of a problem but the direction isn't going to change. I know of at least one fella working with 10-12* timing in some pretty silly winds with good results.

[GearBear]

For years on our Eurosport arms we only ran 10 degrees of timing. Now some of them are up to 25 but that seems to be rare still. In my wing cars, I don't want anything over 40 degrees on a X12 arm. But for flat track GT12 I'm starting to like the .540" diameter arms with 45 degrees of timing. A lot of that has to do with the fact that I gear these cars really low, so I'm not looking for torque off the line as much as I am a high revving motor, and the higher the timing the better they seem to want to wind out.

I would think for Drag motors, you would want a middle of the road timing, something that will have both good grunt and yet still enough timing to have a decent top end. Although a lot of drag cars have ridiculous gear ratios in them!

[havlicek]

Thanks for the VERY interesting information about all this guys. I'm doing another Hawk right now while I have "Hawk" on my brain and just for giggles. This one will be a #28 wind on the stock arm (although with the shaft replaced) with a Bugenis com and with some advance, but even less. However, this one won't have Emovendo magnets, I'll try both the stock neos (it's the newer white endbell Hawk) and maybe even a set of ceramics. The one thing I noticed when checking out the neos is that they are poorly matched in strength. Unlike the stronger Emovendos that always seem to be well matched, the stock neos were off significantly. One side measured well over 1200 and the other side measured just about 1100. Anyway, I think this wind will "make sense" in the Hawk, although I can't get it dynamically balanced because Bill is down in Brazil, so I'll have to static balance it.

-john

[Marty N]

I would think for Drag motors, you would want a middle of the road timing, something that will have both good grunt and yet still enough timing to have a decent top end. Although a lot of drag cars have ridiculous gear ratios in them!

10* eh? Pretty punchy I would think? Yea, that's a question.

Now that is interesting. My Neo/FC which has been 139.15 MPH on tall gearing has run .443 @ 126.26 MPH with a short time of .0605 seconds on shorter gearing with a motor build of .490 hole, KRM Quad Neo that gauss 3800. .480 Koford L blank 64 wind at 15* timing. Low and very tight. I have other motors that are in the hunt with gaps around .020 at 24* and that about brackets my range.

John, you are correct on the stock black Hawk Neo's. Poorly matched indeed and as a composite Neo about as strong as a set of Parma ceramics. I meter the stock Hawk ceramics around 900. 25* has been about the top for both sets in my testing.

[Russell Sheldon]

John, your motor builds are just awesome!

Regarding neo magnets, have you tried Pro Slot's new Velociraptor magnets? While the name is dreadful, I'm told the magnets are excellent and were specially made to Dan De Bella's specs. I think that the Hawk neo magnets are linear, while the Velociraptor are radially orientated.

Personally, I prefer polymer cobalt magnets for Euro-type motors -- if I can find them - and never more than 15* advance.

With kind regards,

Russell

[Alchemist]

Hi John,

My "BlackHawk" motors look incredibly awesome! The wrinkle finish looks so purposeful too!

Regarding neo magnets, have you tried Pro Slot's new Velociraptor magnets?

Hi Russell,

The Velociraptor Neo-magnets are what I sent John to replace the stock mags in my BlackHawk motors - it should be very interesting to see how they run. I'm looking forward to testing them out!

Ernie

[havlicek]

Regarding neo magnets, have you tried Pro Slot's new Velociraptor magnets? While the name is dreadful, I'm told the magnets are excellent and were specially made to Dan De Bella's specs. I think that the Hawk neo magnets are linear, while the Velociraptor are radially orientated.

Hi Russel, and many thanks I actually thought the ones I installed for Ernie (he sent them) were Emovendos as they look outwardly identical. I have no way of knowing or telling the difference between them, but let's just say they're both VERY strong indeed. They're so strong that installing the arm is a little difficult as it gets sucked right out of your hand many times I know that the Hawk neos are of the "matrix" type (tiny bits of neodymium composite material in a polymer matrix formed into the shape) and Dan's appear to be solid and nickel plated.

Personally, I prefer polymer cobalt magnets for Euro-type motors -- if I can find them - and never more than 15* advance.

I've yet to build any motor with cobalt magnets and all the eurosports arms I've done went into some pretty hairy setups built by Lou Pirro, and wound to Bill Buegenis' specs. I've never held a functioning strap motor in my hands working down in the salt mines at the winding crank

Hi John,

My "BlackHawk" motors look incredibly awesome! The wrinkle finish looks so purposeful too!

Hi Ernie and thanks They should be interesting motors to play with. I would think there will be gobs of torque in such a small package.

_______________________________________________________________________________________________________________

While working on Ernie's motors, I did some experimenting with brazing as I had to braze the tabs on the stock Hawk com for one of the motors and they're kind of fragile. I came upon an improved method of brazing that seemed to worked more reliably/consistently. Having just finished another Hawk rewind (with another Bugenis com), I tried the same method and it really does improve things significantly as far as electrical integrity and mechanical strength, putting what looks almost like a neat little fillet of solder (*but it's actually 1200°F jeweler's silver) on the tab. Things are still a tad touchy for me when doing this...especially if I don't time my foot on the switch and contact with the heater tip and the tab, resulting in an arc and often a demo'd com tab. In any case, here's a closeup of some of the brazed connections with that nice little lump of silver on there:
...still making progress, "wax-on/wax-off" It's the niggling details that keep me up at night and just when I "thought" I was doing OK, I met Bill Bugenis and Lou Pirro who both showed me how far I have to go

Speaking of the above Hawk, I took the neos out of one of the new Hawks and replaced them with a set of ceramics that measure nicely at around 900 or so. That's the setup for the above wind which is a #28. The arm comes in at almost precisely .195 ohms per pole (my meter sometimes works when the mood strikes it !?, today it was in a good mood). The arm was done again with my "super secret special pattern" since, when it works out for a particular wire gauge, # of turns and arm blank, I get a more compact coil. Here's the beauty shot:



I'm pretty sure that this arm in the Hawk setup with the ceramics will be a screamer, that's also not so "on the edge" as it would be with the neos...but I probably will test it with both magnet types to see what's what.

Last thing, Bill is in Brazil for the Eurosports Worlds. Does anyone know of a good dynamic balancing service that takes PayPal? I have a little bit of money in there I'd like to burn up and this arm seems to deserve the "full monty". TIA

-john

[Bill from NH]

Try Alpha, I find Paypal listed on their website.

[Marty N]

Paul gets my vote too. Does all my arms and very well I might add.

BTW no one has a method yet to produce radial Neo magnets. You can segment them to mimick it though. Sort of

[Alchemist]

John,

Those micro-welds look so precise as though it was machine welded!! Do you use a micro-tip to do this?

It's always exciting to take one's skill to a higher level. Your technique is awesome John!

Many thanks for taking the time to put these "BlackHawk" motors together for me.

Ernie

[Alchemist]

The stock com seems pretty skinny for such large brushes (I think Mike Swiss did a neat brush mod to overcome this) and after seating/breaking them in, they look to me like they would basically almost always be shorting between two com segments.

It sounds like it is not a good thing John! Shall I expect a "short" track life - LOL (pardon the pun!)??

Thanks!

Ernie

[havlicek]

Hi Ernie and thanks ,

They're really not properly called "welds" since there is another metal used to fuse the wire to the tabs. I think in slots though that all these connections are called "welds" generically. The connections at the com are really important though because you can see the change in the resistance of each pole as you "weld" them. On this particular arm, the poles' resistance was off by maybe a couple of hundredths of an ohm before the welds. Afterwards, they were within a thousandth of an ohm or so. Then I cut the com and they were off again by a little ...but I then remembered to clean out the slots between the segments of gunk that collects there during the cutting and they were right back where they should be. When you have an arm where the poles are under .2 ohm, those seemingly slight variations can make a difference. Anyway, getting a solid connection with 1200°F silver (silver being one of the best conductors there is) is excellent insurance against both failure and poor conductivity.

It sounds like it is not a good thing John! Shall I expect a "short" track life - LOL (pardon the pun!)??

Beats me I doubt it's a particular problem though. It just seems weird that the brushes are basically the same width as the com segments...sorta like the time that the brush is "on" a segment is VERY short compared to the total time it takes for one rotation. This sorta thing comes up with Mabuchis when you swap out the 16D sized brushes for the larger 36D ones. The motors seem to work much better when you use a large com with the large brush, while the small brushes work just fine with the small coms. I'm guessing though that with these modern motors they've (the REAL experts at the factory) worked this stuff out and I'm probably over-thinking things.

-john

[Alchemist]

You might feel you're over-thinking these things, but I always do appreciate the feedback. I learn something every time!

Would "solder joints" be the better definition of the "welds"?

Thank you John!

Ernie

[havlicek]

Hi Ernie

Would "solder joints" be the better definition of the "welds"?

Nope, "solder" is a name for a bunch of low-melting point alloys with tin and sometimes lead or silver or other small trace amounts of metals. These connections are (I think) more properly called "brazed" connections.

-john

[Alchemist]

Then "Brazed Connections" it is!! I'll refer to them that way from now on.

Thanks John!

Ernie

[havlicek]

Hi Ernie,

When I'm not really focusing on the method used, I'll say "welded" myself as a generic term. In this case, I just wanted to be clear since looking at the picture, it looks like solder (to me anyway). Really, when you think about welding, it's generally fusing two pieces of metal with heat. "Soldering" is bonding two pieces of metal with a third metal which is solder, BUT in this case the third metal is silver...so it's like "high-temperature soldering". Since solder alloys melt at anywhere from say 375°F to 450°F, and the silver I use melts at around 1200°F, there's a big difference as far as the strength of the joint and it would be impossible for the heat of the motor to throw a com connection IF the brazing is good. Like I said above too, silver is one of the best conductors...if not THE best (I think it's even better than gold in this regard), so the silver adds no significant resistance to the equation. With copper melting at just under 2,000°F, the silver can fuse at safely below the melting point of the copper, but waaaaaaaaaaay above any likely temperatures the motor would encounter without vaporizing first

As a side thing, I take apart many motors where the com connections ARE "welded" and it looks to me like they use some sort of resistance spot-welding type process. Probably a very short/very hot "blip" to fuse the tab and the magnet wire. I don't know which is the preferred method for high-end motors or if both are used, but it would seem to me that brazing might be the better way...although less practical for higher run production arms. The thing is, it can be difficult (at least at the home brew level) to do brazing on such a small thing as a com tab and in many cases with thin magnet wire and get good results. I've been refining this one detail for a few years now, and am still improving. Even the shape of the heater tip is REALLY important, as is the material the tip is made from and the power source. The brazing metal also comes in many types and alloys, so there's a bunch of experimenting to go through with that. Now I have a way to do this that leaves a better fillet of brazing silver on the tab, and it's only because I had to figure out a way to do one of your Hawk motors...so thanks!

-john

[Alchemist]

it's only because I had to figure out a way to do one of your Hawk motors...so thanks!

Allright - I'll take responsibility - LOL!!!

Seriously John, I must thank you for your time and effort that you put into each and every "rewind" build you produce. Especially mine!!

I am indeed grateful!

Ernie

[havlicek]

Part of a group of 7 motors (4 26D and 3 16D) headed for Italy. I had one Mabuchi BB can left here so I used that because I wanted to do another red/red combo...just because I think it looks sweet Two are #30 winds and twp are #29 winds. Super clean motors all with Arcos and sweet runners.



-john

[Alchemist]

Wow John!

What a set of "gems". That red on red motor looks hot. It's exciting to see your work go "international" - congratulations.

Ernie

[havlicek]

Thanks Ernie,

Over the past couple of years, I've sent quite a few motors to various countries in Europe...a bunch to Germany, England, Italy and even a couple to France and Spain. They seem to like the vintage stuff a lot over there, as well as thingies too...my kinda people!

-john

[don.siegel]

Amen John!

The commercial slot racing boom was short but intense here, and a lot of my slot buddies experienced that at the time (66-68), some then stopping and some continuing through the club scene in the 70s and 90s. Fortunately, there are also some younger racers who like the vintage scene for various reasons - maybe it reminds them of racing with their grandfathers...

I'll be back on the thread pretty soon, because at our last vintage meeting I managed to burn out two stock Russkit 23s! One I lent to a friend when his own period rewind burned up during qualifying (the Russkit ran well, but popped a wire after three segments), and the other in my own Russkit Porsche Super Spyder, which made it through the 8 heats, but started seriously slowing down in the last segment and a half. Haven't looked at that yet, but just disassembled the loaner last night and the windings on one of the poles was darkened, and a wire had come off the commutator...

Will be rewinding that one and checking out the other... I counted about 107 to 109 turns on the Russkit 23, and the wire may be 32, 33 or 34, can't tell for sure! (I thought I had seen Rocky identify these as 34, but that seems kind of small for a "6V" motor.)

My poor friend also loaned an MPC Mako Shark to another friend, and that motor burned out too! Very unusual to see three usually solid motors burn out. It's an electronic power supply, rated at 120 amps (they also run X12 motors, it's the Nieuport club in Belgium); not sure what the voltage was set at, but maybe higher than 12 volts. And besides us, didn't seem to be an unusual number of motors getting burned out - it was my first in all these years of vintge racing!

To be continued...

Don