Question: Trying to launch a projectile by spinning wheels faster results in less distance achieved. A problem of torque?

Setup: Two 555 motors set up to grab an object (a ball) and launch it. These motors are powered via an H-bridge that is being controlled via PWN by an Arduino.

Observation: As I spin the wheels faster I notice I’m no longer able to increase the distance I throw the ball (and I think sometimes it decreases in distance?).

What I’m trying to solve: Trying to understand why this occurs, and if I should upgrade my battery voltage, upgrade my brushless 555 motors, or make my wheels of more dense material.

I’ve observed as I increase the duty cycle I can get the ball to be launched further, to a point. After a certain point I no longer see further distance achieved. Instead I notice an audible slow down to the motors after launching a ball and needing more time to spin back to full speed. It’s making me wonder if with increase of speed I’m losing the ability to launch the same object (same load) with as much ease? Perhaps the wheels are being slowed down (akin to braking) before launching the ball?

I’m wonder if, as I increase speed, I’m decreasing the torque in my system? https://www.rctech.net/forum/attachments/electric-road/426694d1236465944-novak-sentry-brushless-dyno-torque-vs-angular-velocity001.jpg. Decreasing the angular momentum should draw more current and increase torque. That increase in torque is what is launching my ball, I think?

1) Will increasing the maximum voltage from 12v to 24v help if I’m already seeing a stallout as I get to about 60-80% on duty cycle with a 12v battery?

2) What part of my equation should change if I adjust the material the wheels are made of (to make them heavier?).

3) Am I right in believing a 50% duty cycle PWM means I am powering the wheels with effectively 6v?

submitted by /u/fake_namest
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