My team is qualified for worlds but is in need of a rebuild. We run an internally stacking double four bar lift and intend to keep that general theme. Because we are in need of a rebuild, I need to know what gear ratio with what motors I can have the fastest lift possible WITHOUT TIMING OUT. Four motors will be our maximum amount of lift motors. I’d be ok with reducing my lift to less than four motors but I do not want to give up speed and reliability so I guess having less than four motors is a no go. In summary, how aggressive of a gear ratio would I need to have the fastest lift possible without sacrificing reliability. I really do not want the lift to time out.
Before we begin this topic, leverage, friction, as well as height is pretty important regarding gear ratios. How long is your bottom four bar in holes, how long is your top four bar in holes, as well as what is its’ capacity?
You should easily be able to do a full length lift with four motor 5:1 torque lift without having issues burning out, and probably even a 5:1 speed lift with good rubber banding
I presume you are talking about dr4b… because a double 4 bar is very different from a double reverse 4 bar.
Anyway, if you are sticking to 4 motors, then 5:1 speed should be fine… assuming your quality of build is ok.
I would start out with either high speed 1:7 or high torque 1:5. If you don’t run into burnout issues, move to turbo or speed gearing. It’s much easier to change internal gears than external ratios. Make sure you use rubber banding too.
Hey it’s the Perry team! With our double reverse four bar we had four high speed motors running 1:7, 1:5 might work well though. However, I just finished building another DR4B that lifts with two motors because it’s mainly made out of standoffs… it works tho!
Yo it’s Perry! We never thought we’d see you here. On our current robot, we’re using two regular motors and a 1:7 gear ratio. We use quite a bit of banding, and it’s very stable and never times out. But if you’re looking to push the limit and you have four motors, 1:5 HS seems to be the way to go. We’re currently testing some modifications to our own lift for even faster driver loads…
Wow look at all the Ohio teams in this thread that must be a new record. But 4 motor 1:5 with HS motors should work fine if your lift isn’t really big and is all aluminum. Make sure to use good rubber banding and you shouldn’t burn out.
Sup Ohio kids. (I don’t think this is a record number of Ohio teams in a single thread btw)
We were running 7:1 speed with 2 motors at state. No problems there. (The lift was like the only thing that worked well on the bot by my standards.)
5:1 speed with 4 motors should be super easy. Turbo would be pushing it to the limits. I don’t even know if it’ll be noticeably different even if it did reach top speed with turbos (which I don’t know if acceleration will be enough).
Build well, and rubber bands. Triangle too.
With 4 motors at your disposal you should have no problem going 1:5 turbo or even 1:3 High speed
So I rethought and realized that 7:1 speed with 2 motors wasn’t even close to pushing the motors to their limit (from empirical observation). 5:1 speed with 2 motors is worth looking into. 5:1 turbo is likely very possible with 4 motors, as mentioned.
With the speed possible with 2 motors, I don’t know if using 4 motors on the lift is completely worth it anymore. I think I would prefer an 8 motor base 2 motor lift over a 6 motor base 4 motor lift.
I believe they are referring to a double reverse, not a mini four bar…
For the record we run a REVERSE DOUBLE FOUR BAR