Our team is in the process of building a catapult but we want to make sure we have a good gear ratio we are not sure. Please give me recommendations.
We are doing a 12-tooth (The gear our motor is on) to a 36-tooth to an 84-tooth. This has worked amazingly as far as torque but we had to use 2 motors because of the gear ratio.
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I recommend you try different gear ratios and document the pros and cons of each in your engineering notebook.
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I would recommend 24-72 with a red cartridge. because it’s decently fast but manageable.
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my team runs 100 rpm motors on 24 tooth slips to 60 and the slips are reversed so it spins the slapper 130 loads per min.
We used a 36 : 84 gear ratio with a red cartridge 100 rmp motor. This has never given us any issues whatsoever.
36 to 60 is solid aswell on 100 rpm
we use a 36 slip 3 times to a 60 and 300 spm
I wouldn’t do 36 to 60, because you wouldn’t want any rpm above 50
We’re going to be rebuilding our catapult and are thinking about doing a 12 to 48 tooth gear ratio with a 100 rpm motor because it is 25 rpm and has a bunch of torque. 12 to 36 is also a great ratio and provides good torque with good speed and you can make it faster if you have it travel a smaller distance.
We have that on our catapult currently, and we need 2 motors for it to actually make the match loading work (on a platform in front of the catapult). Even with 2 motors, it still overheats a bit sometimes, and I have to keep the speed at 35 - 40 percent otherwise it’s too fast for us to match load.
We did 24:60 with a red motor. Shoots fast asf and is pretty powerful.
I would recommend a 36t slipgear to an 84t gear. Works pretty well.
This is a pretty good ratio, and my team currently utilizes it. However, unless you need a pretty big range of motion for your catapult there isn’t really any reason to choose this over a 24-72 tooth ratio (besides possible material concerns).
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Our team used 1:4 and it worked amazingly, sometimes getting 2 shots per second.
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How much did you guys shave for the cata?
This depends on your starting angle for your catapult, I just changed the angle yesterday so I will have to cut a new gear but ill probably end up shaving about 10ish. If you want to know for personal use, I would suggest shaving 5 off then seeing how that works then shaving 1-2 more off and continuing until you find the right amount (Pretty much just guess and check)
How do you guys keep it stable? Our cata goes from 12 to 60 at 100 rpm and it slows down sometimes.
Doesn’t have to be
Revised for degrees = teeth shaved:
(Degrees*teeth on cata gear) / 360 = teeth per slip
If you’re going to use this formula, I would recommend not immediately shaving off the amount of teeth that the formula suggests, but cutting a couple less and then going from there.
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