Best Way to Launch unusual items?

We were talking and whats the best way to launch unusual items, such as lunacy balls, breakaway balls, frisbees, footballs and other random object you could also find around the shop?

A specially designed hammer?

Catapult/Slingshot, unless you know a way to make a wheeled shooter account for every shape change :rolleyes:

Do you want to launch these objects more than 30 ft?

Wheeled shooter with suspension to account for various ball sizes.


This or use a large foam wheel, similar to 118 in 2013.

This faux TED talk covers some of the parameters of odd items being launched.

When you’re shooting a variety of various shaped items long distances, wheeled shooters aren’t going to perform as well. Wheeled shooters as we know them in FRC work best with objects that can roll / spin - balls, frisbees, etc. We are abe to design such precise and repeatable wheeled shooters because we are shooting such an incredibly narrow range of items - a single game piece, with manufacturing tolerances being the only varying factor. Wheeled shooters also shoot multiple game pieces in quick succession really well, which doesn’t seem like is needed here. Wheeled shooters are solving the wrong problem.

A catapult cares much less about the geometry of what is inside it - it brings itself and its object up to speed and stops at the angle producing the desired trajectory. Obviously this will have varying results with each game piece as well, but I think it’s a better solution for the constraints at hand.

Take a look at what 16 did in 2012 as a starting point.

Most FRC grippers are made specifically to hold a certain size/shape/weight piece, so most of the usual tricks won’t work. Some sort of speed-controlled catapult/ballista (I’m thinking motors and encoders) could be used to get everything up to an appropriate/consistent speed. To hold the pieces, I’d try a gripper that can accommodate many shapes, probably by having multiple pneumatic arms that curl in on the “game piece”. You can use the thing on the other side of your wrist as a rough template.

The argument was started while going over the design of our hockey puck shooter on whether we should go:

air powered(paintball gun like)
inline wheel shooter(ultimate ascent)
top wheel shooter with roller bottom(baseball shooter)
Spring loaded plate(pinball)

or is there something else more efficient to shoot the put accurately at really high speeds for our challenge.

i’ve seen 3996 use a hammer to kick basketballs back in 2012

This is an amazing opportunity to make plywood ghetto prototypes and do some good ol’ fashioned testing. The three main things that peoples are suggesting are catapults, slingshots, hammers (all easy to prototype) and wheeled shooters (more difficult but doable).

Things like air power can probably be crossed off the list because getting a seal on a lunacy ball would be… lunacy (sorry, I had to) as well as accommodating the different shapes and sizes of the other pieces.

I think that a catapult would work best in this application but have no real experience (and neither does anyone else as far as I’m aware). Unless someone here can point to an off-season project they’ve done shooting multiple different gamepieces I would take everything with a large grain of salt. Implementation is an entirely new can of worms. If you do go for a catapult there are multiple options; lots of motor, stored energy and release (surgical tubing/spring), pneumatic, something else I’ve inevitably forgotten. Each option has advantages and disadvantages.

I did a catapult a few years back for rebound, with our initial prototype we saw potential because it did give the arch but it isn’t what would be needed for this project which is more speed.

and as for a slingshot i know people (my team included) made kickers that were a piece of lexan held back and then released to exert a force to kick the soccer balls.

Have you tried more power? You can relatively easily get catapults to launch really far and really fast. You can flatten the exit angle for it to go faster but not farther.

33 using a catapult to full court shoot in 2014

Don’t know if that works for a hockey puck trying to reach 100+ mph

Building a generic shooter that can accept objects of basically any size or shape and propel them to 100 mph is a really, really, really tall order. A catapult launching generic objects at even as fast as 40-50 feet per second is a lot more possible.

I’d suggest a linear punch shooter with an adjustable holder (like 1986, pink team, 948, etc in 2014). Really easy especially if the accuracy doesnt have to be that great

If you want 100+ mph, I would suggest air cannon. Just use a sebot to account for the various object shapes/sized. :cool:

what is a sebot? and one of the small scale prototypes we will test tomorrow is an air cannon.