Lite body advantages for standard wheel base

[M Tull]

Hi Everyone,
Are there any advantages to creating a super lite body such as a ladder design or something similar to what Bulldog outlined in the thread: "Bulldog-How to make a super strong, lite body!" if you are restricted to using the existing axle slots?

Thank you

 

[Crash Enburn]

In all cases, the lighter the body, the more condensed the weight is in the rear of the car where you want it. Our engine is gravity, and you want the biggest engine you can have.

If you have to use the slots, you can either lop off one end of the car and glue it to the other so your rear wheels are all the way back (5/8" from the end), or you can drill your own holes and then fake the original slots (a double width of hacksaw blade should do it).

If you don't do anything to move the axles back in the car, you are limited in how much weight you can put behind the rear axles — too much and your car becomes an ill-handling wheelie machine.

 

[Mojo Racing]

Wheelie contest ! ! !

I swear ! We should have one of those !

 

[M Tull]

Thank you guys. Regarding the axle slots, I found it's easiest for me to recreate using a 7 1/4 blade on my table saw. The blade is the same thickness as the OEM slots (roughly 1/16 ~ 3/32). I like the double hacksaw blade idea ... I can have my scout recreate the axle slot. Regarding the movement of the axle location by cutting an 1/8th of the back the car and adding it to the front ... I've seen that mentioned before ... I'll see if our district allows it ... has anyone documented the variance in the axle slots among several blocks? Is there an 1/8 inch variance and that's where the "1/8th inch" change comes from?

Thanks again guys for sharing your experience and knowledge

 

[bracketracer]

It's not a huge boost in speed to build an ultra light scout chassis vs a thin but un-lightened chassis. It's enough that if your competition did it and you didn't then you will be at a small disadvantage. Better prep and alignment would overcome the difference. Big reason not to depends on the track you have to race. Crappy stop section? Crash box? Young kids handling the cars? All equals the need for a sturdy build. A better track lets you build lighter without fear of damage. "In order to finish first, first you must finish".

 

[Crash Enburn]

Wheelie contest ! ! !

I swear ! We should have one of those !

I'm thinking a car design similar to this:

Regarding the movement of the axle location by cutting an 1/8th of the back the car and adding it to the front ... I've seen that mentioned before ... I'll see if our district allows it ... has anyone documented the variance in the axle slots among several blocks? Is there an 1/8 inch variance and that's where the "1/8th inch" change comes from?

You'd have to have an exceptionally stick-up-the-butt district to have rules to come down on that. If your kid makes a car that is shorter than the full block, the axles would effectively be moved.
The short end of the block is approx. 1 inch from the axle slot, so you'd be cutting 3/8" off of that. Or you could lop off the long end. Whatever the case, cut the block such that the car ends 5/8" from the rear axle
As to the slots having variances and being off, whatever they have been off would be exceptionally slight. If you picture the manufacturing line, the blocks are all sliding along sideways, side by side, and two saws are cutting perpendicular slots into them. I think the slots get a worse rap than they deserve. YMMV.

 

[Mojo Racing]

Heck yeah ! ! !

The car has to be able to make it to the transition on the front four wheels, then the force of the transition causes the wheelie the rest of the way down the track...

Hmmmmm... things to ponder

 

[M Tull]

"In order to finish first, first you must finish".

... good point! My boy did better than I thought he would regarding the handling of his car at the pack and district races while others had a great time playing catch and "crash" with theres.

 

[M Tull]

I'm thinking a car design similar to this:

You'd have to have an exceptionally stick-up-the-butt district to have rules to come down on that. If your kid makes a car that is shorter than the full block, the axles would effectively be moved.
The short end of the block is approx. 1 inch from the axle slot, so you'd be cutting 3/8" off of that. Or you could lop off the long end. Whatever the case, cut the block such that the car ends 5/8" from the rear axle
As to the slots having variances and being off, whatever they have been off would be exceptionally slight. If you picture the manufacturing line, the blocks are all sliding along sideways, side by side, and two saws are cutting perpendicular slots into them. I think the slots get a worse rap than they deserve. YMMV.

Thank you ... I'm brave enough to move the slots an 1/8th of an inch ... I'm not sure about 3/8ths ... maybe we will do two cars and see what we can get away with. I can cut the axle slots of the bottom of the block first in order to avoid shortening the car the width of a saw cirf ... then cross cut the slots back in.

 

[M Tull]

Bracketracer, Crash Enburn, Mojo Racing,

I realize this thread is a bit old but wanted to thank you all for your advice last year. We followed all of you're advice this year. We made two cars. One with the rear axles 5/8 from the back the other rear axle was left at 15/16 from the rear. Both cars were 5/16 thick and were hollowed out. We didn't remove all the weight we could for ruggedness .... as bracketracer said "In order to finish first, first you must finish" ... so I think each body was 15 grams roughly. Sorry guys no Wheelies just yet.

During tuning night we raced last years car (a bit beefy and heavy from tail to nose) against both of this years cars. As you all stated it does make a difference.

The end result ... my sons car was faster this year and were going to districts again this year.

Thanks again
M.

 

[Mojo Racing]

Congratulations ! ! !

I am glad to hear that you were able to make things work more in your favor this year. Wheelie cars are cool, but they are not meant for drag racing. LOL

When I coach boys at my place, I make cars that are beefier for them as well. I don't try to get their cars as light as the ones I build for league racing because a cubs hands (or the person staging their car) are not as caring on the car as mine are. And generally, the car bodies weigh between 12-15 grams.

Good luck at districts !

 

[M Tull]

I'm happy to say my son's car ran very well at districts ... he won all three races thanks to all the knowledge shared on this forum and DD4H products. His car was all BSA components and made mostly by him. All I did was cut the body on the table saw and supervised. Of course I also spent allot of time on this forum ... in order for me to teach my son the best approaches I have to know how myself.

I'd say the best advice I received (which is not mentioned often) was: In order to go fast you have build more than one car a year. For some reason that really sunk in last year more so than all the other great advice offered on this forum.

Thanks again everyone!

 

[Mojo Racing]

Nice job ! Congrats to your son and you for the districts win ! I sure he is very happy and you are very proud.