88 replies to this topic

[Pablo]

Like (almost) everything at The Wolcott Ranch, this car will be "for sale".

But my intent is to make it run in the "World Challenge" proxy "Just for Fun" class - no rules.

 

Body is a Toytech, WB is 3", wheel widths front and rear are about 2 1/2", pan width is 2 3/8". Configuration will be anglewinder.

 

Motor is a Havlicek custom built "Peanut" motor - modified FK can, Pro Slot endbell, arm wind is Group 20. It was installed in a Pablo Go Kart for one (road course) race, had way too much power, baggied up and marked "H20, one race.  FAST. Gears too tall for The Dungeon with 36 spur".

 

Perfect powerplant for this build. Small, lightweight, very powerful.

This is going to be the fastest Mini Cooper I've ever built 

 

 

https://www.youtube....h?v=q5cgVbAYui8

[eshorer]

Now if you can just figure out how to make it sound like that Mini in the youtube! Maybe a tiny piece of something hitting the gear, a la "bicycle card on the spoke" of our youth?

Cool project.

Eddie

[Pablo]

Oh I guarantee you this G20 arm in the peanut setup will deliver a real sharp whistle 

[Pablo]

Planning/Parts gathering begins. Peanut has a 9T 64P pinion already installed.

 

My gearing guessing says, if it was too violent for a road course motor at 9/36/.750 = 5.3,

it should be perfect for a straightaway launch at a similar FDR. I found a 46T alum. drag spur and a pair of .930" OD ProTrack wheels with fresh rubber in the fridge. 9/46/.93 = 5.4 something. Close enough.

 

Mocked up, it looks like it will work fine as an anglewinder 

 

 

 

 

 

[Martin]

The body you have there is a Mini Sprint. A small co. in the U.K. chopped the roof and added flares 1/1.

My 1/24 Stock car 1969 was a Mini Sprint. Still have it. Great little slot car.

[Pablo]

Thanks Martin 

 

I trimmed a little rotating fat from the pinion then oiled and tested the Peanut, since it's been in a baggie for months.

Draws 1.8 amps at 5 volts, runs cool, sounds very potent 

 

 

Ready to begin loading the jig, but haven't decided between Parma O-ring or Samson BB fronts yet. 

For now, I'll start with the rear axle tube. Right rail goes straight forward, left rail gets angled, and I'll go from there

 

 

 

No rules baby, running with scissors

 

[Dan Searcy]

I've had this for a few years now.  I put this Toytech body on it a year or so ago.  The previous owner soldered a wheelie bar onto a Womp chassis.  I put a super 16D in it, nothing exotic, and it's a hoot.  Runs in the high 7's on a 1/8 mile strip.  My favorite drag car by far!

 

Can't wait to see your finished product.

 

 

[Pablo]

Thanks Dan, I love flames and Mini Coopers, and I love your car 

 

I spent a lot of time mocking up the drivetrain. Everything is a trade-off. To get the motor closer to the axle I changed to a 10T pinion. Here is what I have so far

 

 

A 10 pinion is going to really load the car hard off the line, but I will keep that in mind as I build the chassis 

[Alchemist]

Looking real good Paul!

 

With that type of motor potency, I presume the wheelie bars will need to be longer than the car?!  LOL

 

Ernie

[Pablo]

Thanks Ernie 

 

I can write my understanding of slot car drag racing on the head of a pin with a Sharpie 

It's the "Just for Fun" class, so what can possibly go wrong?

 

My goal is to put the power to the ground and not de-slot, but it's hard to "unlearn" 55 years of road course mentality.

In an effort to get the motor even closer to the axle, I'm planning to "tip" the motor upright

 

 

Similar to a Banshee build I did a while back. The car lives in Canada. Last I heard the owner said it was a rocket

 

 

 

 

 

 

[Bill from NH]

Direct drive would get the weight even further rearward. Wheels for .078 axles are around.

[Pablo]

It's not a weight issue. If it was I'd just put the motor in the trunk 

[Bill from NH]

Then is that the only way you can get the gears to mesh? It's common practice to tip inline drag motors on their side, but that raises the CoG. Not an issue for your application. I saw some neat 1:1 Mini drag cars on a FB video last night.

[Pablo]

It's the only way to go full sidewinder. That way the initial "twist" of the motor gets applied evenly to the flag.

Or at least that's my "newbie theory" 

[Pablo]

Which wheels do y'all like, the O-rings or the BB retros?

[Rotorranch]

I like the retro wheels myself.

 

Rotor

[Don Weaver]

Pablo - Do the front wheels on dragsters touch and roll?  If not then ball bearings add nothing but weight to the party.

 

Don

[Rotorranch]

Nose weight matters.

 

Rotor

[Don Weaver]

Jeff,

 

Thinking more of the cost of ball bearing fronts vs cheap Parma o-rings.  Weight can be added cheaper.  But then I'm a penny pincher from the good ole days! 

[Rotorranch]

And they look better!

 

Rotor

[Bud Greene]

What are you going to make the rails out of

[Pablo]

Bud, main rails will be .055 single wires.

 

Don, in this proxy they give extra points for "Appearance". I think both types of wheels look cool.

Who knows what the judge will prefer? No rules for "touch and roll", so I can use what I want.

 

Still undecided on the front wheels, but thanks for your inputs Jeff and Don 

The Samson front wheels really are lightweight, but they require a 3/32 straight axle.

The Parmas use a 1/16 axle and it can be angled and hinged.

 

All I have for now is a rear axle tube with a drip hole and ProSlot BB's soldered home.

Will be laying the rails later today 

 

[Pablo]

Yes I know I've changed my mind many times, so I'm sorry for that.

But I'm not sorry for trying to nail it the best I can.

 

There is no test track. I have zero drag experience, other than the Caddy and two duckys.

That hardly makes me experienced. So I have one chance to make it right, and the car has one pass to perform.

 

I have to guess on a lot of things, which makes me nervous. Main rails are .055, motor is anglewinder, and I'm using JK retro .812 OD retro wheels as jig blocks. Strange, but it works. Anyway, one rail goes straight forward, the other is angled to parallel the can.

 

Motor is centered for left/right weight balance and axle tube with BB's is centered in the jig.

I have decided on the Parma O-ring front wheels.

 

Again, thanks for those who gave opinions and input. Onward 

 

[Larry Horner]

Looking good Pablo and I think you made the right decision going back to an angle winder. I thought the rotated can sidewinder design look uber cool but my own experience with drag bikes (real ones) is that the lower your CG, the more effectively you can transfer the power to the ground.

 

And now for a ignorant question from someone with very little angle winder experience. Does the slightly improper gear mesh when the arm axis is below the axel have much effect on performance? I know this same debate has raged for years regarding offset inlines and my personal experience is that any performance loss there is very negligible and I suspect that is the case here as well. Still, I also suspect part of the reason for such small tires on angle winder road cars is to minimize this offset.

[SpeedyNH]

in my experience, with a good set of properly angled gears you can minimize loss from the funny mesh. it works with cobalt anglewinders, which will quickly destroy a badly meshed gearset. of course nothing's perfect (like correctly-profiled straight spur gears), but you can come pretty close.