138 replies to this topic

[Bobby Page]

Yes, I agree, you can't go wrong with black or metalflake. But every man should drive a pink Cadillac at least once in his life, especially if it has a little Las Vegas gold flake mixed in it.       

[Bill from NH]

The pink Caddies are Mary Kays.

[bluecars]

We don't want to know how you know that, Bill. 

[Cheater]

Too bad you couldn't find one of the Monty O. rewound 36Ds he use to build for BPR hardbody racing.

That would be pretty easy to find...

If he wants one, I have the one I won in a Slotblog raffle a couple of years ago, with Arcos and a Monty arm.

[Pablo]

We don't want to know how you know that, Bill. 

Uh, maybe because they have Mary Kay stickers on them ? Just guessing...
 
Greg, you can send the Ohren 36D if you want and all I can guarantee is, at some point it will go to a good home.
But I've no doubt the H-Power I have will strip gears and chew up donuts just fine.
 
I still haven't investigated all options for my Caddy just yet...

[Bill from NH]

Red, some flat track racers (CASRA, ANE AMCA, PNW AMCA, & ISRA) have used Mary Kay hand lotion as a tire dressing for years. The few Mary Kay ads I've seen on TV have included one of her pink Caddies.

I think a pyramid scheme is involved, that when a salesperson sells a certain amount of her products, she gives them a new pink Caddie, too. Just so you know, I drive a silver Subaru and the only Caddie I've ridden in was a limo at O'Hare in Chicago and it was black.

[bluecars]

Amway comes to mind. In my early 20s I was invited to get rich. Lucky I didn't fall for their crap. But I did eat a lot of their donuts.

 

Pablo, I know what ever you do it will be cool. Hope to see you Sat. I know the weather isn't going to be great.

[Pablo]

I've made up my mind - it has to be a dragster. Anything else would be a poor compromise. 

 

Custom H-Power 36D can drive motor, 44 turns of 28 wire.

During break-in, shows classic happy signs typical of vintage motors - amps gradually decrease, level out, then slowly increase until steady.

Stayed room temp. When re-oiled and fed some volts, it's good. 

 

 

Pablo scratch built sidewinder chassis

- Wheel widths 2-3/4" front and rear

- Wheelbase 4.5"

- Guide lead 5/8"

-Threaded axles/wheels

 

I've never built a dragster before, so I'll need to study rules, gearing theories, etc.

 

Lots of homework to do... 

[Pablo]

These eBay horrors may serve as bad examples if nothing else

 

[hiline2]

That will be eligible for the 36 Class drag races we running at DC PUNK!

[Pablo]

I learned some basics from the SDRA rules - 3D interior, clearance level 1/16", fronts >3/4" OD, rears >.950" OD, max length of wheelie bar 5" from rear axle.

 

There is no class for 36D motors, so I guess I'll just make it a "fun" vintage car.

 

The eBay horrors actually did help - with a gearing starting point. 16/48 = 3/1; wheel OD 1" gives a final drive ratio of 3.00. But that is a stock 36D.

 

So I did a "quick n dirty" - subtracted one tooth off the pinion to allow for the hot H-Power motor, 15/48 = 3.2/1; wheel OD 1", final drive ratio 3.20

 

A 1" OD wheel needs a .875" OD spur to clear 1/16".

 

Drag racers, if I'm making mistakes, please stop me. 

[hiline2]

There is no class for 36D motors, so I guess I'll just make it a "fun" vintage car.

 

We had a class for 36D motors in our last proxy race. I ran this one for fun with a Rambuchi in a Dynamic chassis.

 

[bluecars]

Aren't drag strips 18v? That ratio sounds pretty high for 18v.

 

But I don't drag race, so what do I know.

[Pablo]

You know about as much as I do, then.

 

SDRA rules are 16.0 to 16.2 volts.

 

To be clear, please define "high," and tell me what you'd gear it.

[Pablo]

As usual, the answer (motor/gear configuration) came to me while dozing in bed at 2 AM. 
Just to make sure, I looked at a lot of gearing options today: 
 

 
I'm convinced there is only one correct option for this car - idler gear setup. It's the only way to make it full sidewinder, and it won't hurt having the weight of the giant motor further forward.
 
My plan is, entire car sits flat 1/16" above the track, 1.033" OD rear wheels, .900" OD fronts, 48 pitch 10/43 gears, motor right side can mounted with an idler gear.
 
I finally found some good info on drag racing (right here under my nose at Slotblog - I should have known) which helped me a lot:
 
Unca Frank Eubel's enduring legacy
 
Thanks, Cheater. 

[bluecars]

High and low gears is funny. 5 to 1 is lower than 2 to 1.

Looks like your heading in the right direction.

[Pablo]

Thanks for (finally) explaining yourself, Red, after two days. But no need to teach me gearing theory.

If you'd have read Slotblog as long as I have, you'd understand slot car racers have different ideas on what "low" and "high" gearing is.
 
You meant less pinion/more spur, and I agree. My original plan has changed in that direction; thanks for the updated input.
 
My idler gear was inspired by a Zimmerman's proxy sidewinder car, and by Cheater's insistence that an idler has no bearing on gear ratio.

[bluecars]

Lots of people have different ideas about things. Can't help that, what is, is.

As usual Cheater is correct about the idler.

Sorry about not getting back to you earlier. I space my time as I only have 5 Gigs a month.

[Bill from NH]

If you use an idler gear, mount it on a bearing to help reduce any added resistance it might add.

[Pablo]

First lesson I learned on idler gears: one bearing with a short shaft and a gear on it won't do. It would wiggle waggle all over the place. So it needs two bearings with some space between to stabilize it.
 
Walking the beach this morning, I found a perfect drag donut mounting cone - it's huge!!

You can see my experimental gearbox gizmo, a work in progress, to the side.
 

[bluecars]

Might be worth checking into a cupped needle bearing. A lot stronger for that app.

Also remember that the motor rotation must be the same as the axle with an idler but I'm sure you've already thought of that.

[Pablo]

Yep, I need to try a couple of those special bearings. Thanks for the rotation advice also.
 
Centering the weight of a 36D into sidewinder mode with an idler gear and 2-3/4" width is a challenge.
Maybe it would be easier if I didn't care about centering the weight left/right, but I do.
 
My gearbox gizmo was a failure but it did teach me a lot. My next idler setup will be considerably simpler, smaller, lighter, and stronger.
 
I don't have much to brag about yet, other than, I think these Buzco wheels and Riggen Magoo slicks would look cool
 

 
Too bad the body skirts would hide almost all the view... hmmm that gives me an idea for the paint job...

[bluecars]

Can't tell if your mocking me or appreciate it.

Anyway nothing special about closed roller bearings, just a stronger approach.

[Bill from NH]

Red,

I had seen Timken roller bearings but didn't know what a cupped needle bearing was. I found some photos on the net. They're my "learning something new" item for today. Thanks!

[Pablo]

Cheater's oval special had an idler:
 
Cheater Wells Oval Specials
 
But my challenge is different than his, since he had plenty of room for the idler gizmo. 
My wheel widths are much narrower, my motor is much bigger, full sidewinder and on centerline, and the gizmo must be to the far right side.

Plus, I have a giant vintage gimbal bushing in the way.
 
Mine will share some similarities with Cheater's, namely, the sandwich design, precise tolerances, and difficulty to build.
 
I'm sure an engineer with a CAD program could do it in an hour. I ain't that guy. 
 
Here is what's left of my first gear gizmo experiment - bent, burned, and broken.
 

 
I have high hopes for gizmo #2. Bigger brass gear, VXB BBs, 3/32" shaft.