As stated before me, I don't believe a hopper is required. With the rule of not being able to control more than 3 balls at a time [G22], a hopper would most likely lead to penalties, as well as a complicated design because you would need to create a method to get the balls to the hopper, and then a method for them to leave the hopper, and make sure of the unlikely event all 3 balls don't jam it somehow. Unless you've made your conveyor less than about 21", you should be good for maintaining control of 3 balls. What our team has is a tower that is going to be at least 29" tall to hold our balls then a secret method to transfer the balls to our shooter mechanism. (Hint - it involves Newton
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