RC Tank Warfare community hobby forum

Estnische wrote: ↑Thu May 25, 2023 11:28 pm There is no exact science. You will have to do it by trial and error. As an experiment, screw your upper hull back on. Then try holding the front of the tank and twisting the rear. Try removing the upper hull then doing the same twisting. You will notice that the lower hull is much more flexible without the upper hull. Plastic doesn’t like constant flexing because it is not elastic, so it is prone to cracking.

This same principle is applied to design of modern racing touring cars. To make their chassis stiffer, roll cages are triangulated and are fixed throughout the shell, including suspension mounting points. Ordinary road cars have torque boxes built in below the door sills to do a similar job. Your ordinary Heng Long battery box acts like a torque box. If you remove it, or use magnet mounts, your plastic hull will also flex more than HL intended. Two common ways to overcome this are a horizontal stiffener plate epoxied to the floor, or vertical bulkheads like those used in ship or aircraft design.

Edit: In my Sherman with both mods, I expoxied aluminium angle to the hull sponsons, and slid an aluminium bulkhead behind the motors.