[roc-chat] Re: Clarification
- From: Jeff Gortatowsky <indanapt@xxxxxxxxx>
- To: "roc-chat@xxxxxxxxxxxxx" <roc-chat@xxxxxxxxxxxxx>
- Date: Sat, 25 May 2013 12:22:28 -0700 (PDT)
Chris I have always used average thrust. But Carlo is right. The first second
of thrust appears to be about 45 or so pounds of thrust. That is a guess from
looking at the ROCKSIM graph on thrustcurve.org.
I have a rocket at 6.5 pounds, and an I100 with a 5 ft guide reaches 41 ft/sec
at guide departure (according to RS). I consider anything above 35 to ft/sec
fine under normal conditions. (I have gone as low as 28 to 30 tho some say that
is too slow. But on a calm day I've done it.)
---------------------------------------
Jeff Gortatowsky, Redondo Beach, CA | Twitter: JeffGortatowsky | Yahoo:
indanapt
"(Scientific) Skepticism is not a set of beliefs, it is a set of methods for
asking questions about reality." -- Doctor Steven Novella
________________________________
From: Chris Coffee <chris_coffee@xxxxxxxxxx>
To: roc-chat@xxxxxxxxxxxxx
Sent: Friday, May 24, 2013 8:22 PM
Subject: [roc-chat] Clarification
A little help here, please? I need to know if someone can tell me if my
calculations are correct for a Thrust-To-Weight calculation for an upcoming
flight...and whether or not the rocket should be flown on said motor? Thank
you.
Madcow Sensor weighing in at 7 pounds on the pad. 54mm motor mount. Using a
Cesaroni I100-RL-LB this is what I got:
Average thrust of motor (according to ThrustCurve) = 98.5Ns
Divide 98.5Ns by 4.45 to get 22.13 average thrust in pounds
Divide 22.13 pounds of average thrust by 7 to get a Thrust-To-Weight ratio
of 3.16:1
Is this correct?
If my math is correct, I would say that the rocket should not be flown with
the I100.
Okay, folks.....school me!!! LOL
Christopher
L. Coffee
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