Add Apogee body tubes. #25

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1. dbcook commented on Nov 3, 2022

   

   dbcook

   on Nov 3, 2022 via email

   Last edited by dbcook

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   Very well organized spreadsheet! However there is a math error in the density formula, which should be pi*L* (R1^2 - R2^2), while the spreadsheet has pi*L * (D1 - D2). The resulting densities are around 10x too small - should be on the order of 0.8 to 0.9 gm/cm^3. Another thing to look at is that the discrepancy between the wall thickness via computing (OD - ID)/2 and the direct measurement is unexpectedly large. Both the ID and OD measurements are noisy by around 1/4 mm which is ~0.010". I know from experience that measuring the diameters and especially the ID accurately is *really* hard because paper tubes stretch and compress a lot more than you might expect. If you fix the formula and use the specified ID/OD instead of the measured ones, we get very reasonable and consistent +/- 6% densities in the expected 800-900 range. See https://docs.google.com/spreadsheets/d/1KhEGJ8QAPFXo8E5XGFjaVqdR3KyH0S01MR0VuivKUSQ/edit?usp=sharing The Apogee line goes beyond the sizes in the spreadsheet. Going through the current Apogee website I see tubes all the way up to 3.9" that show the mfr as Apogee. Full dimensions seem to be given for all of them, though you have to click into the individual item to see it. The dimensions are within a couple of thousandths of the Estes equivalents.

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   On Wed, Nov 2, 2022 at 8:18 AM sjh114961 ***@***.***> wrote: I am adding this as a proxy for Vaughn Stegeman, who chooses not to sign in to github. Please add 13, 18, 24, 33 mm body tubes from apogee. I have provided actual data from parts I have. Apogee Tubes Data.ods <https://github.com/dbcook/openrocket-database/files/9921734/Apogee.Tubes.Data.ods> — Reply to this email directly, view it on GitHub <#25>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADXORH3JCDMWA4366BL322TWGKA6FANCNFSM6AAAAAARVGCVGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>