Help: Snailbot isn't shooting ball up

VEX V5 General Discussion General Forum
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HELP, we finished the 1st design of our snailbot but our rollers shoot the ball down

we’ve tried multiple hood angles but we can’t get the ball to shoot up in any direction

motors:
600rpm indexer/840rpm flywheel
600rpm rollers
200rpm drive
200rpm intakes

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1st of all, 600rpm is a little slow for the top roller specifically. i would recommend gearing that roller up to 1200ish.

2nd,

the problem is not necessarily the angle of the hood. It looks like your angle is a little high, but that is not the main problem. the problem is compression. try moving the hood closer toward the top roller. that might fix your problem. (you may also have to lower the angle of your hood a little bit once you have done this).

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your hood is no good, and you could do with removing that antislip on the launcher and speed it up faster.

The hood should be a fairly tight fight on the ball spaced about 5.5" away from the launcher until you can get like a 45 degree launch angle.

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I forgot about the gearing to 840rpm
we’ll try compression

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u have no compression and nothing that allows for the hood or rollers to conform to the ball’s dimples and diameter tolerances

i recommend redesigning the upper half of ur bot

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or at least designing it.

things like this should be planned before building. It looks to me like you built it as you went, which isn’t terrible but you’ll have much better results in general if you use cad or at least an accurate sketch to determine the proper distances between rollers and hood/backing.

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:flushed:

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Heh, amateurs. Brain cad = best cad

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As mentioned in the posts above, there is no compression. There are a few things I would try to make it work:

  1. Removing the antislip but adding a ton of thick elastic bands on the sprockets.
  2. I can’t tell on the video, but in my experience you need a sprocket size of at least 24t spinning at 600 rpm for it to work, preferably 30t 600rpm, so make sure the sprocket size is right.
  3. Make sure that the top roller is actually spinning very close to 600 rpm and that it’s not much slower due to friction losses and spinning other rollers at the same time.
  4. You want the hood forcing the ball into the sprocket right before the ball needs to go vertical/launch off so it can go into the 18.45" goal, right now you only have it pushing the ball into the rollers very early and the ball ends up jumping over the remaining antislip/elastics and it doesn’t gain any speed. I would have the hood be closer to a 45 to 55 degree angle and push the ball into the rollers for much longer.
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Oh I understand now, so the hood needs to be a little longer and have a tighter fit with the ball to get it to shoot high enough up and at a good enough velocity.

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Seems kinda like flame but your response is understandable because that hood and upper half was more well designed but we ran into a lot of issues and just started messing around to find a solution. That is why the hood is legit made out of a bent piece of scrap metal and the flywheel has badly sewn together antislip mats over the surgical tubing flywheel.

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