Thank you for the links! Both gave approximately the same results. The main
and drogue bays are about the same size (4x7 and 4x6) and the results were a
little over 0.7 grams with the 2-56 shear pins. Yesterday, I conducted the
ground test using 1.0 grams BP for the drogue and 1.2 grams for the main. Both
tests were “energetic”😉 and showed that perhaps around 0.8 grams for each would
do fine. So, I’ll be using 0.8 grams BP for both and 1.0 grams BP for the
drogue and 1.2 grams for the main as back up delayed charges.
Also, these formulas will be used to calculate the amount of BP for the 3”
rocket I’ve been flying. I’ll use the results for the primary charges and
larger amount I’ve been using for back-ups. Always good to not over pressurize
a deployment event. Even when the shock cords are a good length.
Thanks again for the information.
Richard Dierking
From: Chris Attebery
Sent: Sunday, December 3, 2017 1:25 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Sizing BP Charges
I use this one.
http://www.rimworld.com/nassarocketry/tools/chargecalc/index.html
On Sun, Dec 3, 2017 at 12:38 PM Alexander Jones <uscjones@xxxxxxxxx> wrote:
I use these:
Ejection charge size, static sample port size, and shear pin calcs:
http://vernk.com/EjectionChargeSizing.htm
http://www.vernk.com/AltimeterPortSizing.htm
http://www.feretich.com/rocketry/Resources/shearPins.html
On Dec 3, 2017 12:26 PM, "Richard Dierking" <applerocketry@xxxxxxxxx> wrote:
I misplaced my chart for BP based on volume that also had the extra BP amounts
when there are shear pins (for example 2-56 or 4-40 nylon).
Does someone have this info? Perhaps it came from one of Canepa’s high power
rocketry books.
Thank you,
Richard Dierking
P.S. No, I don’t want to blow it up, just a good separation will do.
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