19 replies to this topic

[havlicek]

Following my "Yellowjacket" build, here's another for a member:

I filled all the holes and tabs with solder, and sanded them smooth before installing the inner can shim and painting. Shown here with a blank Champion endbell, but I later decided to go with one of the improved "Hong Kong" Mabuchi endbells. Arm has been built and spaced, ready for powdercoat:



A shot of the inside of the can and shim with a nice strong set of C motor magnets:

 

The finished arm, wound 38t/27 on the .518" x .460" blank... finished diameter is .514", comm is a Mura with drill blank shaft:



The finished motor. Magnets were honed to .530" and tolerances are as tight as I dare on a Mabuchi.

 

Built for can drive, the can was drilled per C-can pattern, can reamed for the new 6mm x 2mm can bushing shown:

 

These endbells are of a much better material than either the Champion or Mabuchi endbells, so I soldered the hoods, installed spring post sleeves, wound a set of .015" springs, soldered on some beefy leadwires, and stuck a fork in it:

 

 

The motor is super fast and winds up and down in half a blink... maybe less. This, to me, is a "full on race motor" for a Mabuchi... serious business for sure! You wouldn't want to slam this thing around for an hour just for the heck of it, but it should be a real hoot in the right car with the right gearing.

 

-john

[Pablo]

Strong lookin' mill, all right.

[SlotStox#53]

Sweet! Probably good for one of those cars to get out of the box for a few krazee laps and big smiles. 

[havlicek]

Strong lookin' mill, all right.

 
Thanks, Pablo... you should hear the thing. It sounds way stronger than it looks!  
 

Sweet! Probably good for one of those cars to get out of the box for a few krazee laps and big smiles.  

 
Thanks, Paul.  

 

It depends on the car and the set-up. In the right car with the right gearing, it should be pretty safe. Then again, nothing will kill a motor faster than the wrong ratio and/or the dreaded-and-deadly "too tight" gear mesh! The motor is 1.5 amps at 6VDC (no load) and gets a little warm, but not alarmingly so at all. On the other hand, with the set-up so tight, it's even more important that the car it goes into is prepped right!

I've said it before, but I have to wonder about Mabuchi rewinds I've seen with big wire arms and really hot double winds. I guess some of them held together for a while and others just went "POOF!"?
 
-john

[Gator Bob]

Nice one, John!

[havlicek]

Thanks, Bob!  

Using the larger (.518" as opposed to the .510" Mabuchi) diameter arm made things significantly tougher here, and stepped up performance by a significant amount. Like I said, as tight as I would dare in one of these things, but it does whistle a fairly frightening tune!  
 
-john

[Gator Bob]

I like when they sound like one of those 'siren whistle rings'... without all that drooling.

[C. J. Bupgoo]

What's the timing on that Little Man, John??

[havlicek]

Hi Michael,

 

Timing is roughly 15-20 degrees advance CCW (as viewed from the endbell). The white dot on the can indicates (+) and the arrow in my logo indicates direction of best rotation.

 

-john

[racie35]

The closer you get anything to detonating...the more I like you. Push that envelope!

[havlicek]

Thanks Bruce.  Well then, I've got a #23 drag motor coming up fairly soon you're gonna really appreciate...no really! Motors like this one aren't all THAT hot, but the old setups aren't nearly tight and precise enough to go much hotter and have the motor be useful.  I used to "push it" on about every arm, but getting better at the techniques means that hotter arms last and run better/safer.  A #23 is still VERY HOT no matter how you slice it though!

 

-john

[SlotStox#53]

A #23.......................

That would definitely push past the *safety* margin on the old setups

You mentioned a #23 in a thread the other day and been waiting to see you create such a beast!!

[Pablo]

"*safety*" ??  Heck, Paul, this is Slotblog, not Gentlemen's Quarterly OSHA doesn't live here  

Keep adding a tooth to the pinion until she cooks, then back off a tooth

[Bill from NH]

Paul E., I drove a friend's (Ken Stevens, now living in Houston) Thorp 23 on the original Modelville Sovereign in 1973 or 74. That wing car had the most brute power of any slot car I drove in the 70's & 80's.  I own one of John's 23S but don't currently have a local raceway in the area to try it out. Maybe someday.

[racie35]

"*safety*" ??  Heck, Paul, this is Slotblog, not Gentlemen's Quarterly OSHA doesn't live here  
Keep adding a tooth to the pinion until she cooks, then back off a tooth

Knowing your limits is not only good.....but fun.....push on mr Havlicek.

[SlotStox#53]

Don't worry Pablo **sarcasm ** was engaged and alive & kicking when mentioning safety

Limits? What limits

[Pablo]

I ain't worried about you at all, Paul   Damn the torpedoes, full speed ahead

[proptop]

Hey John...nice lookin' motor! (As always )

 

Speaking of that 23 wind...what magnets do ya recon would you be thinking of using?

 

If, for example you were to use a long stack vintage late 60's or early 70's Champion arm blank...built for torque perhaps?

[Gator Bob]

Limits? What limits

 

The Outer Limits ?

[havlicek]

 

 

Speaking of that 23 wind...what magnets do ya recon would you be thinking of using?

 

If, for example you were to use a long stack vintage late 60's or early 70's Champion arm blank...built for torque perhaps?

 

 

Long and strong Tom.  I'll have to dig around and see what's in the crypt

 

-john