Catapult Competition Q&A

Q: Will pulley systems be allowed?

A: I am all for innovation and challenging the process, so I want to say yes, but if you have any questions send me an email and we can provide clarification that will hopefully give some guidance.  Safety is key, though.


Q: We noticed that the maximum height  from the ground cannot exceed three feet while the throwing arm is in its rest vertical positions. I think we understand this configuration, but just for clarity, can you provide an example to illustrate this?

A: The catapult will be measured in “rest” position with the surgical bands relaxed. I would say the 3 feet restriction is the maximum possible height the catapult measure. For example, if you are using a stop bar to control the launch angle, it would be the maximum angle, the catapult at rest, and measured to the top of the launch cup.


Q: With respect to the statement  “Tubing must be stretched in a linear fashion” – does this requirement mean that the machine will have one end of the surgical tubing connected to the throwing arm and the other end of the surgical tubing connected to the frame (linearly)?

 . . . obviously the machine cannot be an “onager” style catapult with a torsional spring.

A: As long as they are stretched linearly, it is within the rules. My thoughts were exactly what you were stating, that one end would be mounted to the frame and the other to the arm to provide the rotation.


Q: For the “Pop-a-Shot” challenge, will basketballs be launched or will tennis balls be used?

A: Tennis balls will be used for the entire competition.


Q: What are the specifications for the surgical latex tubing?

A: There are no specific restrictions other than it being an elastomeric tubing with a maximum length of 6ft. This is a key “engineering” decision for the teams. Workout bands are acceptable since they are tubular in shape.


Q: Concerning the “surgical latex tubing,” last year some teams used exercise bands.  I deliberately bought “surgical latex tubing” to ensure my teams met the specifications.  So, bottom line: what is the competition’s definition of “surgical latex tubing.”

A: Exercise bands are acceptable as they are probably more accessible to many than finding surgical tubing. Specifically looking for tubular elastomeric materials for the potential energy, not necessarily latex or surgical.


Q: My design also includes a doorknob , just a literal door knob, the whole thing, is that also ok?

A: Absolutely, any commerically available off the shelf parts should be. We are more concerned with it meeting the safety requirements than necessarily what parts you choose. As an engineer I could not in good conscience limit your ability to be creative.


Q: If I decide to put cosmetic designs on the catapult will the cost be counted against me, I can make a value assessment of the catapult with and without the extra cosmetic parts, meaning one assessment with the fancy paints and props and a separate assessment that is the actual catapult (everything the catapult needs to fully function)

A: That is a great idea to separate out the form and function costs. We don’t necessarily count against teams for cost, but it is a consideration for designs that are close during judging. The focus of the cost comparison would be function and I will be sure we have a discussion about it with our judges.


Q: I understand that I cannot be behind the catapult whatsoever but am I allowed to be right beside the catapult , I’m asking because I’m planning on having a lever to pull to activate the catapult, but because the catapult this year is only allowed to be 3’x3′ I need to be close to the lever to reach it, so would it be ok if I was beside the catapult to pull a lever activating the catapult, I will not raise or adjust the catapult as I’m shooting, I will simply be beside the catapult pulling a lever.

A: This is one of the key additions to this years catapult design specs. You cannot stand directly next to your catapult and need to be able to release the catapult from 36 inches “from the plane of action”. This is the plane that launch arm rotates in, so basically you need to be able to release standing 36″ from the side of launch arm. Footholds (less than 2ft from the side of your catapult) can be added from the main body of the catapult and will not count against the maximum 36″ requirement.


Q: Are ball bearings allowed in the competition?  

A: Yes, ball bearing are allowed for the competition.

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