So right now we are attaching a motor to our DR4B, and I say that we need at least a 1 to 5 ratio. But my teammates say that you don’t need a gear ratio, we have rubber bands, blah blah blah. How should I convince them?
I might show them the DR4B tutorial by 333A:
Or show them videos of good DR4Bs and how they have ratios. They just need enough power to lift, and direct drive isn’t enough imo
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tell them rubber bands can’t account for the weight of cubes and rubber bands aren’t magical (and that’s coming from me)
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I mean they said if it comes to it, they will put 50+ on each side…
Show them this:
https://www.reddit.com/r/vex/comments/eje5ly/dr4b_problem_the_first_time_the_dr4b_can_go_up/
and this:
https://www.reddit.com/r/vex/comments/ejea4n/dr4b_not_working_4_393_motor_127_power/
same robot but shows how even with a light load, 4 393 motors, and tons a banding, a dr4b cannot go up.
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also don’t forget to account for chances in elasticity over time and inconsistency in rubber band elasticity even when new
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Should I just add those direct drives and then we test it, it fails, then I could be like “Ha, now we have to make a gear ratio!”?
State how the motor has to lift the weight of the cubes. You probably wouldn’t even be able to lift the weigh of 1 cube
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Probably not, they’ll probably just be like:
A D D M O A R B A N D S
Honestly, for any lift you are going to need a gear ratio. I would suggest at least a 1:7, but 1:5 could be fine if you have good build quality
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I would use a 1:7 tbh. Show them this page to prove that no one else thinks it can be done. Infact, one of our teams is having issue with power on a 2m 1:5 dr4b rn. if you really want to, just hold motors to the axles and let them test it if they are that stubborn, I’ve done similar for my team.
Btw, are 2 motors supposed to connect to the same axle?
They can, but usually there are 2 towers with 2 different 4 bars, and there is a motor on each driving each one up, and the 4bars are braced together
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Rarely ends well because the axle must be exact length, but possible. you should run an axle across the dr4b though from some of the other gears to keep them mechanically linked.
Having a direct drive dr4b, even if it did manage to work, would be impossible to control
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