I was thinking of starting a thread on Suspension systems, and how scratch build tank/truck/AFV modellers, as well as scale model manufacturers, determine how soft, or hard, to make a suspension system. No matter how detailed your scale model is, if it bounces around like a jumping jack firework, when encountering obstacles, it's not going to look impressive. In fact, it will look like a
toy- and that's not what we want.
Ideally, you want your suspension to emulate the real thing, when mounting obstacles, or crossing bumpy ground. Driving over a rock should produce this look:
(This was the Comet in US paint, prior to the SCC15 paint job.).
Adverts for Heng Long tanks, on Youtube, now stress the realism of suspension systems- of their proportionate scaled-down reaction to meeting obstacles. Running over Dennis the Menace, would be one example:
It has to look convincing.
For small obstructions, the tank should stay almost level, ideally. For this to happen effectively, the strength of the springs has to be proportionate of the weight of the tank. That way, you get the right amount of deflection, wheel after wheel, when grinding Dennis into the ground. For this, the springs- whether tension or compression- have to be soft enough to move individually, but firm enough to bear the weight of the tank.
Believe it or not, there's actually a formula for calculating spring strength:
Mostly this is used for springs on sports cars, but could be scaled down for models. Here's a guy actually using it to determine the right spring to fit to a Lotus Elan:
and this is how to use the spring formula/equation:
https://suspensionsecrets.co.uk/how-to- ... ing-rates/
When you build a scale model, then I think that hardest task is-(the one that turns hair grey quicker)- finding the right spring resistance, and the right type of spring.
The Comet will run with the springs I fitted, but I found that- especially at the back with the weight of the motors-if I pressed the back of the tank down, it took to long to recover- or return to it's default position, that is.
Here it is creeping back to battery, so to speak (a slow recoil...
):
Worse still, without bump stops fitted, the wheels can actually make contact with the return rollers.
Now, that can't be good. So, I shall think about devising some bumpstops before trusting a MFU with this drivetrain. The TK 6.1s (the MFU I'm thinking of using) was fairly expensive, and a bad lockup could burn it's precious essentials...
"Get your facts first, and then you can distort them as much as you please"- Mark Twain.