0 to 200mph in 1.5 years...step 2 - How to chop it?

Email the tech guys, it is all conjecture till you talk to the source.

 

Yes, it might be harder but I am a pig expert and still fucked up

I have been through the pipe dream faze with my boss, memorizing the rulebook and talking to the tech guys will save heartache.

 

I think I have read somewhere that the Rule at the time of the Chrisman Coupe said that it had to have 7" of windshield.
But it not say anything about raking it, so raking it was a loophole in the rules...
Also it seems to me that the top of the windshield is cut higher into the roof than the sideglass, and the driprails are shaved, so the area over the side windows looks a little tall.
If the car is going to be outside todays coupe classes, you dont have to worry about the minimum 5" of vertical windshield glass, so I would clean those areas up a little and I would chop it a lot more.
Take what ever the amount the Chrisman Bros took out of their pillars, and take another inch ( or maybe two ) out of the area over the sidewindows...

 

As I understand this project, the car will be a street-legal hot rod and will be driven from K.C. to Bonneville and back. It will not be built for any particular class nor will it attempt to break any class record(s). The goal will be to go 200 mph and will only be for a personal record, that being main thrust of this endeavor. I would suggest that the safety specifications set forth by the sanction should be addressed first. Any class that the car would fall into would be irrelevant as there will be no class record attempt in any case. Once that has been accomplished then the aero-shape necessary and the horsepower and gearing required to achieve that speed would be looked at. Has anyone considered doing a conventional hot rod top chop and adding, perhaps, an add-on polycarbonate piece ahead of the A-pillars to obtain a shape similar to the above photos ? This could be installed just prior to any speed runs and removed for the trip home. Once again, since no class records are a goal, the car could have a streamlined nose, a rear spoiler (also installed prior) to keep the tail nailed down, and a bellypan. I have no land-speed record experience but it seems to me that reaching 200 mph becomes a matter of aerodynamic design as much as a measure of horsepower.

Just my $.02 worth.

 

Grim,
I have set here staring at your plans and can not come up with any reason why it would not work as you have it. Doing the doors first is not a bad idea at all. I did the same thing on 2 different chops that I have done.

I am interested though to see how you work out the windshield. But you say you already have a idea about that as well. There will be a lot of force pushing on it at 220+.

I am also tring to remember jst how fast Mr. Currie got his roadster wasn't it? I know he used it as a highway car as well as a salt runner. Might be worth a look at his.

Wish there was more I could do to help. Don't mind getting greasy, but the drive from your place to mine is a killer!

 

Is the 30-31 coupe body a given or could you use a 28-29? The reason I ask is because more 28-29 roadsters are used on the salt than 30-31's. I don't have a SCTA rulebook, but there is some big deal about the cowl areas on the early and late bodies. You can unbolt a 28-29 up to the coupe pillar and for some reason in the rules gives the 28-29 an advantage. ROLLCAGE: Remember, you have to have a full cage so visability will be real poor on the ride out there.Good luck, this will be a fun project!

 

Have you considered sectioning some of the beast? Would give you a bit more turret and less body, more proprtional in my eyes.

Kind of a 3/4 scale.

You're not just pushing wind with the roof but the whole body.

 

[ QUOTE ]
Any class that the car would fall into would be irrelevant as there will be no class record attempt in any case.

[/ QUOTE ]
Right until you get to Tech. If you build a 150 mile car but configuration and engine size put it in a class where the record is 300, the car must pass tech for 300. Oddly enough, little things like 300 mph tires (and the list goes on) cost more than 150 mph tires. I'm not trying to be argumentative, just trying to keep you from "blind-siding" yourselves. Wayno

 

i recently saw a pic of jack coonrod's '33 willys coupe from about 1966 or '67. he had chopped it previously but wanted it to be more slippery. so, he laid the winshield way back (just like your photoshop pic) but he did NOT lay the doors or a pillars back, so from the side it still looked like a normal chop job, but from the front sort of a wedge / wing effect with built in spillplates (the door jambs) looked pretty good and was way easier to fabricate as well. i can find you some pix if you are interested in this option.

 

Shave the drip rails and extend the side glass higher into the roof.

 

Lots of good ideas here. The thought of streamlining being as important as horsepower is a key. The thought of a big roll cage in a severly choped car is a key. I'm thinking of an A coupe with a body section, a not so hard chop and a front grill that resembles a '33. The grill being out more at the bottom, tilted back at the top, break in the center with the sides of the grill at sharper angles than original blending into the hood sides. For the runs, most of the grill opening would be blocked off for better aero. The slant back grill would lend itself to directing air over the roof of the car while the sharper angled sides would deflect more air arond the sides. This keeps the radiator in front where it belongs.

 

Kevin....I see the Chrisman coupe and the Dobie Gillis car both use a curved windshield. I can't help but wonder if the extra work involved with cutting a curved glass and getting it to fit a square car would be worth the bother. Are you guys contemplating use of the curved glass?

 

Dobie Gillis car/Chrisman car are the same car. Sorry about the small pic.

 

[ QUOTE ]
Elmo Rodge - That's something we hadn't thought about. (or at least I hadn't) And it's a damn good point. Rule books still arent here (wonder if sodbuster is home for me to hassle today?) but as soon as they are I promise everyone I won't sound like as much of a numbnuts.

Hard not to get stoked and jump ahead with plans and concepts after the dicision was made to do this.

[/ QUOTE ]

and remember, once you hit 200, all of a sudden those records that meant nothing while you were dreaming this up, will be important when you realize you might just take a few home! build the car you guys want, but build it to fit into as many potential classes as possible with as few changes.

 

maybe a guy could insert a stock 34 windshield and frame unchopped -steeply laid back...........Jus thinkin-[I know its dangerous]

 

Check the rule book and see if you can modify the doors to fit flush, what about hidden hinges?

 

[ QUOTE ]
The top corner is completely removed and will not be used on the car. Instead we will take a piece of the door frame left over from the chop and give it several relief cuts, giving it a curve and filling the gap you see in the photo.

[/ QUOTE ]

I've got some extra Model A door tops,if that helps.

Some classes are pretty open for body mods from the A-pillars forward;
but only allow the roof to be chopped,no other body mods.

Frontal area is one big enemy,the other is shape.
Shape creates drag,also lift.

Any air forced to go over top will create lift,just like on a wing.
The Chrisman Brothers used the nose to force the air down the sides,instead of over the top.

Drag is made up of three components:entering the air,going through the air,and exiting the air.
The shape of the front end influences how easily it will enter the air.
How smooth the body is and how well the air stays attatched to the surfaces determines how it goes through the air,and the shape at the back influences how the air closes in behind as the car exits.

I would build the car with the option of adding ALOT of ballast.

 

I doubt these help, but it does show how they incresed the windsheild size for better a view.

 

second

 

Any Race Car is a compromise, and Streeteble Race Car is a even bigger compromise.
From talking to guys that have driven high powered cars on the Salt, it seems to me that Traction and Stabillity, are a lot harder to find than Horsepower.
So that is what I would concentrate on first.
After that I'd worry about Drag, and Horsepower last.
So I'd make as many Driveline, Suspension and Weight distribution decissions as I could first.
Then decide on the bodyshape, keeping Drag and Lift in mind.
For the first year out I'd bolt in a Engine that I depend on and would give me absolutely no trouble, even if it would be down on power by 100 or 200 HP.
The first year out there will be a lot to learn, and that would be one less thing to worry about...

 

Kevin did you see this A coupe in the B-ville pics from this year? I know the windshield isn't laid back, but it sure looks like it'd go 2 hunnert...

 

723 XF VGCC Kowalski Special 116.095 116.307 is what I get on the scta site search.

 

Ryan,
There is a Model A that is from the Springfield,MO area that runs at the salt. Kinda "Chrisman" style, I think that BenD may know his name. I am on my way to stop by Kevins to drop off a "Rule" book and some old magazines with some great info in them:

Popular Mechanics-HOT ROD Handbook, 1956

Hotrod magazine, March 55'-How to build a nose from a 40' Hood

Fawcett Book-How to build Hot Rods-52' (that is the one that Bruce Lancaster was refering to in a post)

I would scan the articles for everyone to read but I can not figure out how to scan with XP Pro when the "driver" for a Epson is not available. If anyone know's how to scan without the driver, could you PM me.

Chris Nelson
Kansas