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Old 03-22-2013, 01:30 PM
mikemech mikemech is offline
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Join Date: Oct 2012
Location: Belleville, Illinois
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Default What am I doing wrong?

What am I doing wrong?

I'm preparing for my L1 attempt with an Estes Ventris. First time with RMS motors. The ship is built according to factory instructions except for a metal tube for the kevlar shock cord. When I sim (RocSim) with a H55W I get strange accelerations.

H55W-10 15g
H55W-14 50g

H = Total impulse
55 = average thrust
W = White Lightning
10/14 = Ejection delay

Am I reading these correctly? I don't understand how a delay change could affect acceleration. If anything a longer delay should reduce acceleration slightly from a heavier motor.

Thanks,
Mike
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Old 03-22-2013, 02:48 PM
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Doug Sams Doug Sams is offline
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Location: Plano, TX resident since 1998.
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Quote:
Originally Posted by mikemech
What am I doing wrong?

(snip)

H55W-10 15g
H55W-14 50g

(snip)

I don't understand how a delay change could affect acceleration.
The max acceleration detection includes the ejection event - ie, it includes all accelerations during the flight including the post-burnout data. With the longer delay, you will get a very hard jerk when the chute opens, and that event imparts the greatest G's during the flight profile. Thus, it is detected as the max-G event.

Try stopping the sim at motor burnout. You will then be able to see the max-G value due to the motor's thrust without the deployment event affecting it.

Doug

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Last edited by Doug Sams : 03-22-2013 at 03:10 PM.
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Old 03-22-2013, 02:52 PM
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ghrocketman ghrocketman is offline
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+1 to what Doug just said.
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