163 replies to this topic

[dc-65x]

How did I miss these? Where was I in the early '80s?    Oh, I remember, never mind.    I was in my early 30s and in my living on a ranch phase. Nothing wrong with that but boy, it was a lot of work. That's probably why I moved to a low maintenance golf course community when I retired . But I digress .

 

I was searching for something on Al Gore's Internet when I came across this wicked six-wheel March 2-4-0 GP car I'd never seen before:

 

 

Holy crap-o-la... talk about innovation.    That's a far cry from today's spec race cars. I knew there were some old time race cars with skinny tires that used four rear wheels...

 

 

... but I didn't know about these later versions like this Tyrrell GP:

 

 

I just got ta build me one of these... 1/24 scale of course. For some reason I kept thinking of Mike Morrissey's Car Model Magazine construction article called "Formula III For Fun"...

 

 

... and the cars in the last inline GP car Pro race:

 

 

So that's what I want to build. A six-wheel version of a late '60s GP car. It needs to have a big Mura 16D motor with tons of power to toast those four rear tires.

 

But, "how do it go?"    Not being a gearing guru I turned to my Slotblog brothers to clue me in:

 

Help With Gearing

 

Thanks, guys! With that solved I turned to my trusty "Rick's Jig" to confirm my gear selection. I just stuck some axles in the jig and tried out what the gear formulas said would work. I had two different vintage Weldun gear combinations on hand that would work with 7/8" rear tires:

 

 

Turns out that a total of 63 teeth in a 64 pitch gear set would give me a gear spacing of .492" with the gears pushed tightly together. Setting them up with a little "sloppski" at a .500" spacing in my jig confirmed a perfect mesh.

 

I'm thinking the rear axle(s) bracket is the key to this build. I'm finishing it up now. I think it's going to work.

 

This is fun. 

[SlotStox#53]

Wow, Rick, that is sounding and looking like a really cool project!

 

Can't wait to see the rear axle/s bracket. Heck, can't wait to see this being built up.

 

Onward!

[Half Fast]

Don't forget the six-wheel Tyrrell P34 which had four front wheels. I saw it run at the Glen.
 
See HERE.
 
Cheers
 
PS: The white Saudia car is a Williams, not a Tyrrell.

[dc-65x]

Williams, thanks!

[SlotStox#53]

I know slightly premature but what are you going to use for a body, Rick?

[Old pink can guy]

Rick, could be wrong but did they have two front tires? I think it was the Willians cars in the late '60s or early '70s F1 cars only.

[MSwiss]

Rick,

Looks like a cool project.
 
I'm sure you'll do a super-top-notch job, as usual.
 
Now that you're not living near Eddie's, if you ever need someone to test this it, I'll be happy to and give a detailed report on my impressions.

[Gator Bob]

Mike, I can't tell if you're kidding... 
 
Rick,
 
Oh boy, is this great!!!
... might be a good candidate for negative guide lead...
 
'Needs more nose weight'... "She'z 'pushin lake a dumbp truuck" _{Darrell Waltrip.}
 
  The six-wheeler (front or back) Was Al Gore's invention... before DARPA the internet... that you were using.

[Ricky Vegas]

We might see the Tyrrell P34 in Ron Howard's 1970s F1 film "Rush" this fall. I know some of the F1 cars we have seen make appearances in July at Road America during their historic races weekend were used for the film.
 
Looking forward to future posts on this project, Rick.

[don.siegel]

Another great project, Rick.

Ranch life, eh? I tried a bit of farm life in the '70s, and that was definitely not for me - way too much work, and stubborn animals!
 
About ten or fifteen years ago, an English guy, Mark Gussin, did a beautiful version of the six-wheel Indy car you show (no, it never qualified). I'll try to find a photo on the Net, but it was in 1/32, and very different from an '80s Mura-powered monster!
 
Don

[Old pink can guy]

It was the Tyrell P34; check it out on Google.

Enjoy,

Ken.

[Tom Eatherly]

Hey Ken,

Look who got second in the consi behind Tom Hansen. Back in the day!

[dc-65x]

Thankfully Eddie's Slot Car World is still open and my buddy Rodney is (also thankfully!) happy to test my projects. He's also a master at tuning and problem solving. I have a feeling there will be plenty of problems with this one!
 
For an inline motor bracket I chose a bare steel version of the French FM-167 Steel Mounting Bracket (also used in some UGO frames). On the right is what's left after dissection:
 

 
I made up these "arms" for the bracket out of 1/16" X 1/2"  thick brass strip. They are tapped for 0-80 machine screws and will also  be soldered to the steel bracket:
 

 
It was critical that the hole spacing is exactly 1/2" as that is what sets the non-adjustable spur gear mesh. Mr. Milling Machine can position the tool to a thousandth or two of an inch. The holes were  bored with an end mill cutter to avoid any "walking" of a twist drill. Then the holes were reamed to 1/4" for ball bearings, unshielded of course.   Just kidding on the "unshielded" as it's just a personal preference thing.
 
Now it's up to my "Rick's Jig" to line this mess up!

[team burrito]

I built that already:

It's not the right body, but it was close enough to make it into a six-shooter.

[Old pink can guy]

Sweet, Russ.

 

Ken.

[dc-65x]

Here is my setup for the four powered rear wheel car I'm building:

 

 

The aluminum goodie on the armature shaft aligns the shaft with the rear axle but allows the motor to angle down until it touches the jig. You can see the slight angle of the motor below while the brass axle brackets remain parallel with the jig. That way the four rear wheels will contact the track evenly:

 

 

Here's the finished rear end:

 

 

I spent a lot of time getting everything aligned. Hey, it might actually work. 

 

 

Now let's see if I can build a chassis around this thing and fit it into a body. 

 

Oh, I almost forgot to give credit to Duffy for the neato rear bearing mounts he machined up. Thanks, Duffy!

[Old pink can guy]

Rick,

 

You need two front wheels, not two rears! 

[Tex]

Holy-Moly, Rick!

 

You are OUT there.

 

Rock on! Superb craftsmanship.

[SlotStox#53]

Wow, that is one serious piece of engineering and design! You and Duffy have produced a really cool start to a fantastic project. 

[dc-65x]

Hey Tex, it's not "way out there" is simple physics... "More is better" so four rear tires are better than two. Here's the proof:

 

 

PS: Can someone please clue me in on the "Korrect" way to link YouTube videos.

 

[Added a new tutorial for you, Rick:

 

How to post YouTube videos

 

Thanks for the suggestion! Cheater]

[racie35]

If the rear wheels are even the slightest bit smaller the car won't know I'd imagine. It would drive like 4 then?

[Duffy]

Wow, that is one serious piece of engineering and design! You and Duffy have produced a really cool start to a fantastic project.

 
Actually all Rick's cool start - the bearing collars are an off-the-shelf item I made, so I don't wanna take any more credit than that for this neat build.
 

If the rear wheels are even the slightest bit smaller the car won't know I'd imagine. It would drive like four then?

 
Yah, but. By that criterion, it could be argued that our conventional rollers are only three tyres in contact, maybe two and a guide... but that don't take the tyres' compressibility into account, or track surface, aero, on and on.

Fact is, this allows the potential for twice the footprint in contact at any moment, when compared to a twofer setup.

Gonna be interesting getting this out to test. I'm gonna lay my bet down right now that you'll end up with real hard rubber back there and a good coat of lead too, Samson-style.

Duf

[Gator Bob]

Hey Tex, it's not "way out there" is simple physics... "More is better" so four rear tires are better than two. Here's the proof:

 

Love that proof... here is more! 

[dc-65x]

That's right on, Bob! Faster is better, too.

 

Another law of physics that applies to slot cars is, "Wider is better". We can only go so far with this one because of the Draconian rule makers but here is the proof for this factoid:

 

[dc-65x]

.....I'm gonna lay my bet down right now that you'll end up with real hard rubber back there and a good coat of lead too, Samson-style.

I think you've got it right on that, Duffy!

 

But I can't wait to find out.