Danno
Well-Known Member
- Joined
- Jul 19, 2013
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Actually - I just read through Walldiver7's thread on static ports, which linked (indirectly) to this: https://www.vernk.com/AltimeterPortSizing.htm Based on that, the formula in Modern HP Rocketry 2 is bogus, so ignore what I said.
I see how they got it from the rule of thumb of one 1/4" hole per 100 cubic inches of av-bay volume, but it doesn't scale that way. That doesn't mean that a 25 cubic inch bay (which is about what the Shapeshifter has) needs a hole 1/4 the diameter, it needs a hole 1/4 the AREA, which is HALF the diameter. Therefore, your 1/8" measurement is right, and my 1/16" is wrong. Fortunately, mine is easy to fix.
I see how they got it from the rule of thumb of one 1/4" hole per 100 cubic inches of av-bay volume, but it doesn't scale that way. That doesn't mean that a 25 cubic inch bay (which is about what the Shapeshifter has) needs a hole 1/4 the diameter, it needs a hole 1/4 the AREA, which is HALF the diameter. Therefore, your 1/8" measurement is right, and my 1/16" is wrong. Fortunately, mine is easy to fix.