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#1
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How many rules does this catapult design break? :)
Prototype @ 35' : http://simhardware.org//img/FirstTry.avi
Slow Motion Study:http://simhardware.org//img/Compound...-2_slow-mo.MP4 Last edited by DavisDad : 17-02-2012 at 04:50. |
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#2
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Re: How many rules does this catapult design break? :)
Hard to answer the question without seeing how it's mounted on the robot, but as a device, it looks effective and legal.
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#3
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Re: How many rules does this catapult design break? :)
Dad,
Is that part of a compound bow with camo that I see? If so, I would want to know how you modified it for this mechanism. I can't tell much from the picture but my first response is usually one of safety and the possibility of this mechanism self destructing in firing. Is the material a laminate and is it capable of a dry fire without damage? I might have a UL safety person check this out during inspection if I was your inspector. |
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#4
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Re: How many rules does this catapult design break? :)
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Other than that, its a wonderful out-of-the-box type launcher. Are y'all going to be at GSR? |
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#5
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Re: How many rules does this catapult design break? :)
Roger that on the safety. I've copied the Mathews mount ("limb pocket"), prestress and string angles as closely as possible. The cylinder (this one is temporary, final will be 1-1/2 bore, 6" stroke) adds a load to string to string during a dry-fire. I think the most likely failure mode would be pieces flying of the pivot arm.
Thank you all for the feedback. This may be a secondary launcher to our already developed spinning wheel shooter. If weight allows. Last edited by DavisDad : 16-02-2012 at 11:06. Reason: typo |
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#6
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Re: How many rules does this catapult design break? :)
Glad to hear you are thinking about that usage in the design.
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#7
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Re: How many rules does this catapult design break? :)
Dad,
I did a search and it appears that the parts you are using required no machining on your part, is that correct? More or less just a bolt on? |
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#8
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Re: How many rules does this catapult design break? :)
Quote:
Thanks so much for the thoughtful response. As a newbie mentor, your help is greatly appreciated. The only parts that I made, that touch the composite bow limbs, are the "limb pockets" parts:
If the shooter works well I may order OEM parts to eliminate doubt about the limb restraints. I have been scrambling to get developed enough to test accuracy. If the performance pans out, I intend to make shop drawings and write up my analysis for review. Sorry I don't have this ready now... |
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#9
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Re: How many rules does this catapult design break? :)
how about
[R14] No individual item shall have a value that exceeds $400.00. The total cost of Components purchased in bulk may exceed $400.00 USD as long as the cost of an individual Component does not exceed $400.00. last time I checked the bow this came from cost around $900... |
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#10
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Re: How many rules does this catapult design break? :)
Quote:
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#11
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Re: How many rules does this catapult design break? :)
I paid $40 at Reedy's Archery shop (Middleboro, MA) for a used set. The guy gave me a discount when I told him about our robot competition. He said he could get $80 used. I assume they cost about 2x that. I couldn't find a price on-line for the limbs new.
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#12
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Re: How many rules does this catapult design break? :)
My son and I tested the latest version of the “compound catapult” yesterday; properly sized cylinder and trigger release (couldn’t exhaust air fast enough}. We hit 6/6 @ 27.5’ (video below) until part failure. We were setting range by adjusting pressure until bow limb deflection was the same as measured by a caliper. We were cocking to about 75% of max force. We are working on the load beam/pressure transducer feedback cocking mechanism…
http://simhardware.org//img/Compound...atics30fps.MP4 http://simhardware.org//img/Compound...tics240fps.MP4 Last edited by DavisDad : 22-02-2012 at 07:42. Reason: typo |
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#13
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Re: How many rules does this catapult design break? :)
I'm planning on making a smaller one of these for a project for college, where did you get the air cylinder from?
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#14
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Re: How many rules does this catapult design break? :)
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You can buy direct from the "Buy Online" page. Have fun! |
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#15
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Re: How many rules does this catapult design break? :)
do you know the part number you used?
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