Sprung weight?

[atcttge]

I've read about unsprung weight, and from what I understand, it is weight that does not put a load on the suspension. So wheels and tracks are unsprung weight.

I've also read somewhere that to make the RC tanks move more realistically, the hull almost remains at a constant level, making the suspension work. For that to happen, the hull should be heavy enough so that when the tank runs over an obstacle, the suspension soaks up most of the obstacle while the hull remains level or almost level. I guess that means adding sprung weight...?

Other than the stuff already inside the tank, what stuff do you add as weights to act as sprung weight?

[PainlessWolf]

Good Morning,
A lot of tankers add a weight bar or fill the lower hull to a slight depth with resin ( adds the benefit of giving a level surface and in some cases is drill-able to mount stuff. Other tankers rely on metal accessories ( I'm in this group ) or use lighter springs at some of the road wheel stations. Whichever path you choose or solution you apply remember to have fun!
regards,
Painless

[jackalope]

We interrupt this regularly scheduled post to bring you some free horse power tips.

Unsprung weight is where you can pick up fuel economy and free power from your real life car as well. Wheel, tires, and axle's are all free hp parts. Example my car with the modifications I have made to it should run a 1/4 mile in the 12.9 range but because my new wheels weigh less then the stock wheels (fronts are 5 pounds lighter each and rears 3 due to my staggered fitment) it runs 12.6's all day.

Each pound of unsprung weight you can remove is the equivalent of adding 5-10hp or there abouts.

Rotating mass or weight if you decrease it will also pick up up some free HP and more economy too! Remove your heavy old steel driveshaft in favor of an aluminum or even carbon fiber one will pick you up a BUNCH! But be warned they're not cheap.

We now return to your regularly scheduled postings on R/C tanks, thank you.

[greengiant]

If you can get it lead will give you the most weight and can be hammered into shapes that fit inside the hull. Don't go overboard on adding weight. Enough is when the suspension acts the most like its real size counterpart.
I recently did a build of a heng Long Abrams during which I added enough weight so the suspension works much like the real thing including throwing tracks off the drive sprockets unless care is taken when turning when on terrain that compresses the suspension allowing the tracks to have a lot of slack in them.

[atcttge]

Greengiant: what kind of weight did you add to your M1?

I'm having a hard time looking for weight bars, so I'm looking to using iron nails in bunches as weight, placing these at the sides and front (gearbox at the rear is enough weight I guess). Not efficient use of space, but at least there's some weight.

I'd like my Leo2A6 (and soon M1) to have the hull go down after a sudden stop from a high speed run, then spring back to normal position like the real deal. I wonder if adding weight up front will also make the tank skid after a sudden stop with all that mass up front maintaining momentum....

[HERMAN BIX]

Best thing to use as ballast would be mag wheel stick on balance weights. They come in strips with a super sticky face that adheres to your flash-as wheels on your car.
They will stick together and are segmented ,so any size can be achieved .

[atcttge]

Ooooh! Good idea Herman Bix! I'll check out the auto shops then for that. Thanks!

[RobW]

Talk to the local tyre fitters, might be cheaper unless you've got an independent motor factors.

Would moving the battery help?

[billpe]

Yes, it would help with distribution. I guess it's also possible to run them (you'll want to double check this) in serial so you could put two batteries in. I know it can be done with Lipos, not sure about nimh though.

Take heed though, the more weight you add, the more your batteries and gearboxes have to work, so less play time and eventually more wear on your gear boxes and tracks.

[RobW]

Thought serial added the voltage? Or was that parallel?