106 replies to this topic

[HarV Wallbanger III]

Beautiful job Rick!

[dc-65x]

Thanks guys. 

 

Joe, I did a rudimentary check of the balance point of the motor and it seem very close to its centerline. That's a good thing because I've already drilled the mounting holes in the axle bracket to center the motor. 

 

And speaking of the motor bracket, I bought the metal for this project mostly from OnlineMetals.com (link below). They will custom saw cut by the inch for small orders like mine:

 

OnlineMetals.com

 

That square tube is about the same width as the motor and its length is perfect for mounting the motor in the center of the car like Rodney and I discussed. It's plenty stout with its 1/16" wall thickness and the square shape acts like a built in rear axle brace.

 

The problem is that it is HEAVY at 1 3/4 ounces:

 

 

To fix that we need...............

 

 

..........no, no, we need HOLES. LOTS OF HOLES.       

 

The early magazine "hop up" articles show holes drilled everywhere. One of my favorite is this modification to an thin aluminum sheet Russkit Carrera chassis:

 

 

The weight savings calculate out to less than 1/10 of a gram. With my thick brass piece I saved much more. The different hole patterns for each side would have taken only minutes to do with a CAD system. I spent hours moving around various size washers on the bracket to see where similar sized hole could be placed, measuring their location and making sketches.........lots of sketches:

 

 

First thing that 1" hunk of tube had to be cut down and squared up:

 

 

No CNC mill, just cranking handles and reading analog travel dials:

 

 

 

It took hours of work but I think the results were worth it. The motor bracket weight was cut by more than half:

 

 

 

It's a big square beast for the back of the chassis......shaped just like the back of the beast of a body I'll be using for this build.  

[Lone Wolf]

Yikes! Wonderful.

 

Love the chamfering. It's all in the details.

 

Kinda puts me in the mood for a grilled Swiss and a pickle.

 

Never saw that Carrera article. Now I know why there are so many of these chassis ruined by amateurs on Ebay.

[Pablo]

It doesn't get any sicker (in a good way of course) than that       

[dc-65x]

Here are the gears to handle the torque of this beast:

 

 

These are solder on gears but I chose to add a 4-40 set screw to the crown gear:

 

 

Here's the big butt end of the ISO center section:

 

 

 

 

[Pablo]

Sir, you may consider giving the FBI a heads up about this build so they won't come knocking unannounced. I'm sure the major automobile manufacturers, in the transition to electric, are already watching you    

[mickey thumbs]

The nose weights on the Cobra remind me of the tractors used in tractor pulls.

[dc-65x]

Guys, it's time to get the front end of this ISO center section in place. The front and rear will be connected only by the motor:

 

 

No, No ...........that's what we don't want it to do. Like a Lotus 49:

 

 

"The first thing to know about the Lotus 49’s usage of the DFV engine is that Team Lotus built the car around it. Not metaphorically, literally. The engine was a genuine stress-bearing member of the car, bolted between the monocoque and suspension/gearbox. Stiffness, already a major string to the 25’s bow? That was boosted, and with the issue of anti-vibration mounts now a non-factor, the 49 was lighter for it. Effectively all Formula One cars followed this technique, the first ever-present standard the 49 introduced to open-wheel racing’s elite series."

 

I chose a hunk of 6061-T6 aluminum bar stock............

 

 

............and machined away everything until it appeared. Of course it had to have lightening holes drilled in it too:

 

 

Bolted up to the front of the motor waiting for the next piece to be screwed on to those 3 tapped holes on the bottom:

 

[Pablo]

[don.siegel]

3 tapped holes Rick? I see the two big ones on the bottom and one small one on the side, but none seems tapped for now - are those the 3? 

 

Nice Swiss Cheese Special in any case! 

 

Don 

[Tom Katsanis]

Don I thought the same thing but in the first pic with it laying on it's next to bar stock you can see 3 holes on the bottom side of the piece.

[don.siegel]

Ah, thanks Tom. 

 

Indeed, it's my keen sense of observation that's made me the famous writer I am today... 

 

Don 

[dc-65x]

Here's the next piece that attaches to the front motor bracket:

 

 

 

Everything is big, blocky and, well, beastly  

 

[Tex]

it DOES look beastly, in a good way! don't get in THIS bad boy's way, or else!

[dc-65x]

Tex, the ISO center section is going to be finished soon and will need some rear wheels and tires. 

I'm using K&B front wheels, Russkit drag rear wheels and Cox front and rear Chaparral Firestones. The rears are urethane versions from Paul's Slot Car Tires:

 

 

I machined the Russkit drag wheels to the same specs as K&B rear wheels:

 

 

The stock Russkit wheel on the left and the machined K&B look alike version on the right:

 

 

The Paul's urethane tire and the finished wheel and tire combo:

 

 

Time to finish off this ISO center section..........

[boxerdog]

it DOES look beastly, in a good way! don't get in THIS bad boy's way, or else!

 

For sure. When you factor in mass and velocity, it should be pretty intimidating!

[dc-65x]

The last piece to fabricate for the ISO center section was the guide tongue cut from 1/8" thick brass bar stock:

 

 

Dynamic style flat head screws holding things together:

 

 

The finished ISO center section:

 

 

I thought I'd see what it looks like with the guide and rear wheels on.........

 

 

........and saw an unflattering familiarity with:

 

 

NO!   Not a Meter Maid Harley trike! It's supposed to be a BEAST.   

[Bill from NH]

You didn't bend any uplift in that guide tongue did you? 

[Pablo]

I don't see a meter maid Harley at all. I see a tractor puller           

 

[Martin]

or this

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[Isaac S.]

Is it actually going to sit that low when finished? 

 

And I agree with Pablo, it looks like a tractor puller. 

[Bill from NH]

Up here, meter maids walk. The Mancherster police had a couple Harley trikes, 30 years ago. I know a NH lady in the town north of me who drives a pulling tractor with three hemi engines, Her name is Roselyn  Knox, she previously raced funny cars. 

[dc-65x]

You didn't bend any uplift in that guide tongue did you? 

 
Bill, oh ye of little faith.      You didn't notice the faint marks across the top of the guide tongue in the first picture in post #42. They were caused by me clamping the tongue in a vise and beating a slight angle into it:
 
 
 
 

Is it actually going to sit that low when finished?

Isaac, the guide will be set to hold the front of the ISO center section up with 1/16" clearance and the rear tire diameter (1.160") holds the rear end up the same:

 

 

 

The Beast will look lots better when the rest of the chassis is attached........I hope!  

[Bill from NH]

I thought those were grind marks on the tongue.   Is the 1/8" brass used "half hard" or something else?

[Isaac S.]

Okay, makes more sense