MARSA54L, flight exceeded 50G

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DBMcCann
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MARSA54L, flight exceeded 50G

Postby DBMcCann » Sun Nov 08, 2015 10:47 am

Having trouble uploading a .fda file, but here's a screencap of the graph. The flight I'm referring to is on Bank 1.

Wondering if there's any way to gain any insight from the data or if it's all junk (aside from baro alt). Not sure if there's any way to open the data in a spread sheet and look at it closer.

Image

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rocketspot
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Re: MARSA54L, flight exceeded 50G

Postby rocketspot » Sun Nov 08, 2015 12:54 pm

.fda file extension added to the acceptable list. I went through and did my best to cover what I could, missed a couple it appears. Try now!
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MarsaSystems
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Re: MARSA54L, flight exceeded 50G

Postby MarsaSystems » Mon Nov 09, 2015 2:58 pm

Is the screenshot a plot of Bank 1?

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rocketspot
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Re: MARSA54L, flight exceeded 50G

Postby rocketspot » Mon Nov 09, 2015 3:07 pm

MarsaSystems wrote:Is the screenshot a plot of Bank 1?


John, thanks for joining! I've let Dave know offline that he can upload Marsa files now, I hope he uploads them soon!
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DBMcCann
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Re: MARSA54L, flight exceeded 50G

Postby DBMcCann » Mon Nov 09, 2015 4:42 pm

Ah sorry, yes. The plot is of Bank1. Bank 0 was flown the day before on the same rocket, on a 38/1200 Loki J1026 cocktail. The flight in question was on a K1127 blue that simmed to 44G.

I'll have to file up when I get home tonight. Thanks for looking.

DBMcCann
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Re: MARSA54L, flight exceeded 50G

Postby DBMcCann » Mon Nov 09, 2015 4:46 pm

I wound up modifying the motor during assembly (screwed up gluing) and it appears I got very lucky. Burned a bit hot.

MarsaSystems
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Re: MARSA54L, flight exceeded 50G

Postby MarsaSystems » Mon Nov 09, 2015 5:19 pm

Dave,

The data looks "normal" There seems to be a spit right at ignition that may have spoofed the integrated accelerometer altitude value but otherwise it looks good.

Exceeding the altimeter accel limit generally will not cause issues. The 50g unit will actually record accurately up to about 57g's. If you spend a lot of time about 57g's the effect will be a little early apogee deployment.

Looks like this flight stayed within the linear range of the Marsa54L 50g accelerometer.

DBMcCann
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Re: MARSA54L, flight exceeded 50G

Postby DBMcCann » Mon Nov 09, 2015 6:25 pm

k1127.fda
(31.31 KiB) Downloaded 144 times


Ah, good to hear. Apogee deployment was good, and as you can see, this was a quick in and out so not much time at max thrust.

here's the data file, I hope.

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patelldp
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Re: MARSA54L, flight exceeded 50G

Postby patelldp » Mon Nov 09, 2015 6:37 pm

Cool! I hope this subforum drives discussions more discussions like this! The data is frequently "not what it appears to be" and is great to discuss as a group.
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MarsaSystems
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Re: MARSA54L, flight exceeded 50G

Postby MarsaSystems » Tue Nov 10, 2015 8:43 pm

Flight data is very useful for a variety of uses. I use it to:
1. Determine what the real Cd of my chutes are..
2. Determine ejection charge sizing based on the "snap" acceleration bump at apogee ejection.
3. Are the baro ports properly sized? (compare the inertial altitude to baro during mid boost).
more...


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