I’m working on a project in my engineering class where we have to create a machine to launch a foam ball 25 ft. The design my partner and I came up with requires us to have an adjustable platform so we can find the best angle to launch. we need to find a way to place the motor at the end of the platform (like a lever) to lift it, however, we don know how much weight the motor can handle in that kind of use, and if we’ll need to add any additional parts to ease the load.
how much can a green vex motor lift in that kind of use? any ideas to make it more effective?
I have no idea what the exact value of this would come out to be, but I can show you the math to get an approximation.
First thing is we need to know the length of the lever. For now, I’ll just call it a variable L.
Here is the torque curve for a VEX motor, taken from their website:
Let’s assume that you’re not operating all the way at the right end because you should have some load on the motor. That gives you about 2.1 Nm of torque. What that means is that your motor can lift 2.1 Newtons (the scientific unit for force, about 0.225 pounds) on a lever 1 meter long (about 3.28ft).
All we have to do is convert this into the units you want, which is pounds and probably feet, although the math is similar with any other unit.
2.1Nm * (3.28ft/m) * (0.225lbs/N)= 1.55lb ft
t=fd, so f=t/d.
F=1.55/L
So this means that based on VEX’s claimed power curve, you can plug in your lever length for L and get the maximum force that your motor can lift, in pounds at the end of the lever. Note that in real life with maybe some gears or other losses, your actual maximum weight might be slightly lower.
To relieve some of that, you could counterspring the lever, which is where you basically use some rubber bands to lift it upwards and have your motor tighten them on the way down.
