2 Rows of 6 Cubes or 7 Cubes, That is the question?

[Pinewoodguy]

Hello All,
Would like to know if anyone has run 2 rows of 7 quarter inch tungsten cubes behind the axle? The cubes are 1.5 mm to wide but they can be sanded to match the body or the body can be widened 1 mm to match the weights.

My primary question is this...
Will this much weight behind the axle be counterproductive to the overall goal of speed? Can the COG be obtained? If it matters the body has a standard 4 1/2" wb and
weights in at 9 grams. Running DD4H 93 axles and Mid America cut wheels.

Thanks in advance..

 

[BulldogRacing]

You could do it, and it could work, but it has potential to wiggle like a flopping fish. If you have a track to test on then I would try it. If you only have time for this one build and that will be your car I would stick to the basics that you've learned here and build a sound car that is proven. You are describing a car that is not an easy build, yes it can be done and can be smoking fast!

 

[CivilWarTalk]

titanium? I assume you really mean tungsten right? titanium is fairly low mass compared to tungsten...

 

[bracketracer]

Mr. Pinewoodguy, why not eight wide? Glue a cube on the outside of the body, in the space of the cavity of the wheel?

I wouldn't widen the body though. Increasing frontal area carries a penalty that is hard to recover.

 

[jatofau1]

I just built two cars. One had more weight aft using 12 cubes and a flat plate. The second one just had twelve cubs. The one with less weight aft is faster.

 

[Pinewoodguy]

Hey bulldog, how's the baby? Growing up fast!
See we cant run inside wheel weights. So I'm asking how to run 2 rows of 7 cubes in rear successfully? Thanks.

 

[Mojo Racing]

even though 7 isn't necessary, you can get there by just having the weight behind the axle and not having "sides" where the cubes are.

you will have to glue your cubes before installation.

 

[bracketracer]

See we cant run inside wheel weights. So I'm asking how to run 2 rows of 7 cubes in rear successfully? Thanks.

Pesky rules, always getting in the way! lol

Then I would do it as Mojo said. Mill a slot all the way across the body, glue in the cubes. I might even overplate with 1/64" plywood so it's not fragile.

Either that, or if you can transcend using cubes, add a tungsten plate to the 2 x 6 cubes. That keeps your weight closer to the car's centerline and enhances stability over widening the weight package?

 

[HurriCrane Racing]

I have run 7 before without a difference in speed. Way too much extra work when a simple plate can have the same effect.

 

[Pinewoodguy]

I have run 7 before without a difference in speed. Way too much extra work when a simple plate can have the same effect.

Thanks. See it's not what you know but who you know! I am glad i asked before committing all the time in to the design.

 

[DerbyDad4Hire]

HurriPain is dead on!

 

[Pinewoodguy]

HurriPain is dead on!

I'm assuming a flat tungsten plate is what you guys are referring to? Also are you guys running it all the way back or over lapping the axle? Does it depend on the. COG? Thanks

 

[GravityX]

I'm assuming a flat tungsten plate is what you guys are referring to? Also are you guys running it all the way back or overlapping the axle? Does it depend on the COG? Thanks

It depends on what the car is asking for. One benefit of running a flat plate of tungsten is that you can tune the car a little by moving the plate around. (Assuming that you have a track to do testing on.) Place the weight all the way to the back if your car can handle it, if not, turn it 90° across the axle truss to the DFW side. If it doesn't work here slide it around, both sideways and forward. Typically, all the way to the rear on the DFW side is a good starting point.