Gear Ratios and Mosfets

Quick question, if you put a gear ration in a gearbox for high rof, but reduce the rof with a mosfet, could you run a higher spring for more FPS? I thought about it, even though it’s a slower rof, all the internals are still moving super quick so it wouldn’t be great to put a strong spring in it. Or am I wrong? How exactly does a mosfet reduce the rof, by reducing the voltage or whatever making the motor turn slower, if that’s the case would it be okay to use a higher spring then? Or do mosfets reduce the rof another way? Cheers.

I made that more complicated than it had to be, basically, can you run a higher spring with a faster gear ratio and just reduce the rof using a mosfet?

I found something, pulse wave modulation setting on the titan v2 for reducing rof, sounds like what I’m after. Would that cause any unnecessary heat. And would running a higher spring still be a bad idea?

not sure i’d bother

start with your aims…

if you want super snappy response: pre-cocking
if you want a slow ROF: 32:1 or 2s battery
supper strong spring: good box

by going say…13:1, staying 3s, jamming a monster spring into it and then using the mosfet to control ROF you are just creating a world of maintenance and stress for yourself…

but yes, that would work…i just have to wonder, why

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Making a motor run slow by lowering the voltage would just mean a lower torque so it defeats the purpose.
Probably also make it run hotter / burn out quicker. Like @zeHamish said, pick a goal and optimise for that.

If you want to use a higher spring, the best way to do that is a strong box, high torque motor and a gear ratio of 18:1 or higher.

Using things like PWM sounds like a good idea in theory to make a motor slower ie 75%, but it won’t increase torque because it’s only powering the motor 75% of the time. It will probably reduce torque by 75%

Only way to reduce speed and increase torque is with gears. 18:1 means that the motor turns 18 times, the gear turns once.
32:1 means motor turns 32 times and the gear once.
So that’s more motor power (strength/torque) behind that single rotation of the gear.

The other thing is that a lot of motors are optimised for a single speed. When you start making them go slower / faster, they will be under more stress and wear out faster (current, heat, vibration, strain etc all play their part)

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Thanks for the replies, I was thinking you could have the one gearbox to suit any build, and just change the spring and adjust the mosfet to your liking. I didn’t think of when you use pwm it will also reduce torque, makes sense.

i started out with the same thoughts…one awesome build, many minor config changes

sadly…it really just doesn’t work like that…

i’m up to 13 units now. all with different configs and i’ll even duplicate my builds for others but ultimately the tuning of the duplicate is specific to the exact hardware and nowhere near the same…right down to the number of shims, which sides etm…even the hopup tunings are different…

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