Feedback on first ladder body

[CM02WS6]

Made my first ladder body and it turned out OK so far. Currently around 11 grams. It is 0.300" thick and the pockets are 0.250" deep, and will be stock BSA wheel locations. I'm going to make a stock-ish style car to enter in the adult division at our district race, just for fun to see how it runs on an aluminum track (our pack has wood).

However, I'm curious for feedback about those three holes in the rear axle cross beam. Those holes are for tuning weight with really small tungsten cylinders, but there's not much wall thickness. I guess I figured that gluing in the tungsten plates would stiffen it up, but now I'm not sure. Still have to drill the axle holes too.

Thanks!

 

[Darkside]

The tungsten bars I use in my cars are part of the structure and are glued in with CA. I've had to take a car apart to retrieve the tungsten and it isn't easy to separate it from the wood. I had to break the wood off a piece at a time and then scrape the remaining glue and wood off the bar with a sharp blade.

Keep in mind I have yet to race a car in the pro leagues, so I'm just telling you what I know from my experience, but my guess is once you glue the weights in it'll be plenty solid. Curious to see what the others have to say.

 

[zigzag]

Made my first ladder body and it turned out OK so far. Currently around 11 grams. It is 0.300" thick and the pockets are 0.250" deep, and will be stock BSA wheel locations. I'm going to make a stock-ish style car to enter in the adult division at our district race, just for fun to see how it runs on an aluminum track (our pack has wood).

However, I'm curious for feedback about those three holes in the rear axle cross beam. Those holes are for tuning weight with really small tungsten cylinders, but there's not much wall thickness. I guess I figured that gluing in the tungsten plates would stiffen it up, but now I'm not sure. Still have to drill the axle holes too.

Thanks!

First of all - looks like you have the right tool for the job.....nice

Nice clean work on the body- I think most pros would just have a much thinner rear axle cross beam and use tungsten cubes and putty to weight and tune. That said, I think you have plenty of thickness in the rear axle cross beam for what you are planning to do and think it will work well for you IMHO.

 

[CM02WS6]

Thanks for the feedback! That tool is a Shaper Origin, a "handheld CNC". It uses a vision system looking at those dominos to know it's position, then corrects within about a 1/2" circle, so you just look at the screen and move it and keep the dot in the circle and it does the rest.

Is the general consensus to drill axle holes before or after routing out the body?

 

[zigzag]

Thanks for the feedback! That tool is a Shaper Origin, a "handheld CNC". It uses a vision system looking at those dominos to know it's position, then corrects within about a 1/2" circle, so you just look at the screen and move it and keep the dot in the circle and it does the rest.

Is the general consensus to drill axle holes before or after routing out the body?

file this one under preference - better to drill the body first and then do the axles in case the body flexes during routing.

 

[Wolfram Racing]

narrow rear axle section - allows weights mounted more rearwards. If it means removing the tuning holes, I think it's a good tradeoff.
thinner crossection - 0.3 inches is a fairly thick car. The weights are 0.25 inches, and you've got plenty of cross brace for stiffness. I'de keep the whole body no thicker than necessary to mount the weights.
route then drill - alignment is king. Routing after drilling can mess that up
Not sure the purpose of the forward longitudinal brace unless you are worried about colliding with something
If you do these, you should be able to get the body down to 6gm or maybe even less. Delicate, yes...but such is the seeking of top performance.
Offset the rear weight pocket toward the dominant front wheel side...maybe 0.1-0.2 oz heavier on the lifted rear side wheel. Offsetting the rear weight will help you achieve this easier.
Excellent workmanship!

 

[CM02WS6]

Thanks for the tips. I think I'm going to change the design very slightly. These don't take long to cut so I'd rather be confident. Eliminate all but one tuning hole, thin up that longitudinal brace in the front, and maybe cut the front two areas all the way through. We're only talking about 1.5 grams total difference so it leaves enough room to push it once I've actually run this

FYI, the longitudinal brace isn't for impact. I was thinking that it would be good to have some structure there, similar to how I've got the X brace in the middle, but doing an X in the front seemed overkill. I'm going to taper the nose to a point like shown in this picture, which wasn't done on the block I actually cut.

 

[Reecedad]

The body looks good