[roc-chat] Re: BP for Deployment of Main Question
- From: David.P.Smith@xxxxxxx
- To: roc-chat@xxxxxxxxxxxxx
- Date: Thu, 8 Dec 2011 11:16:56 -0800
Arghh. Do you math self-check before
sending....
Let me try one thing again. A
7.5 rocket is a bit over 23.5 inches in circumference. The area is
a bit over 44 square inches. Therefore 10 psid gives us 440 pounds
of ejection force...
Hey, who does math at lunch time???
David P Smith
NAR 78668 L2
Amateur Extra, W6DPS
- The opinions expressed in this email are my own and do
not necessarily represent the positions, strategies or opinions of Southern
California Edison, its parent company Edison International, or any of their
affiliates.
|
From:
David.P.Smith@xxxxxxx
To:
roc-chat@xxxxxxxxxxxxx
Date:
12/08/2011 11:12 AM
Subject:
[roc-chat] Re:
BP for Deployment of Main Question
Sent by:
roc-chat-bounce@xxxxxxxxxxxxx
I use the "rule of thumb"
on this site.
http://www.vernk.com/EjectionChargeSizing.htm
So, by that site you would need 4 grams of ffffg black powder.
Remember that you are looking at a lot of area to apply the ejection pressure
to. A 7.5 inch circle had a bit over 23.5 square inches of are. So
10 psid will give you 235 pounds of ejection force.
What is the shear force rating for your pins?
David P Smith
NAR 78668 L2
Amateur Extra, W6DPS
- The opinions expressed in this email are my own and do
not necessarily represent the positions, strategies or opinions of Southern
California Edison, its parent company Edison International, or any of their
affiliates.
|
From: Richard
Dierking <redierking@xxxxxxxxxxx>
To: <roc-chat@xxxxxxxxxxxxx>
Date: 12/08/2011
10:10 AM
Subject: [roc-chat]
BP for Deployment of Main Question
Sent by: roc-chat-bounce@xxxxxxxxxxxxx
Say your main deployment section is 7.5" diameter, 24" long and
using three (3) 2-56 nylon shear pins. How much BP?
Also, what's the advantage of using two or more deployment canisters instead
of just one? For multiple canisters, would you wire in series or
parallel? (One 9 volt battery and Perfectflite WD altimeter with
main deployment at 1100'.)
Richard Dierking
BTW: Kurt, we're not intending to turn the nose into a second stage :-)
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