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Eggtimer TRS data CSV or excel.

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jbrracer

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Has anyone made a CSV or excel program for the TRS data? I saw on the eggtimer site its possible to use the data log to graph, but it doesn't explain how.

heres the data I'm talking about:

notepad file attached
 

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Voyager1

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Save the text file as a .csv file and read straight into Excel. I just did that with your .txt file.
You then select the data from you column headings down and insert as a scatter chart. See below.
I haven't added axis titles or fully separated the data on left/right vertical axes. I'll leave that for you.
 

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jbrracer

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Save the text file as a .csv file and read straight into Excel. I just did that with your .txt file.
You then select the data from you column headings down and insert as a scatter chart. See below.
I haven't added axis titles or fully separated the data on left/right vertical axes. I'll leave that for you.

Thanks for the info I’ll dig into it tomorrow
 

Buckeye

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I assume this is your L2 flight from the thread in the HPR forum, which is now strangely locked???????

I plotted your data as well. Looks reasonable. Your drogue was falling at 30 ft/s, which is way too slow. I suggest drogueless or a streamer to speed up your rate.

Looks like you had a main event around 600 ft, with barely any change in descent rate.

Your rocket was drifting for ~210 seconds, 90% of that time on the drogue. This is the fallacy of dual deployment. A GPS tracker is far more valuable than DD for getting your rocket back.

To cover 1.9 miles in 210 seconds, the wind speed was 32 mph on average. If you were flying at Michiana Mayhem on Saturday, this is very plausible. I was watching the winds aloft on the Windy app, and wind speeds were 25 to 40+ MPH starting at 1000 ft above the surface.
 

Charles_McG

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I've grown fond of the Windy app. Part of my OpenRocket sim tuning is to adjust the chute sizes to match measured descent rates. I've installed the multilevel wind add-in for OpenRocket, and I now attempt to sim descent distance, too.

I also added some 'rules of thumb' direction and distance reminders for the major Bong hazards to my flight day checklist. My last flight of this year reminded me that I should sim both dual-descent and main-at-apogee descent. Luckily, that flight had a happy ending. But I prefer planning to luck.
 

timbucktoo

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I plotted velocity only with an expanded scale and velocity looks pretty constant for duration of descent. Maybe you popped main at apogee?
Untitled.jpg
 
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Banzai88

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If you saw this graph how would you describe this flight ?View attachment 438656
Looks like a typical nominal single deploy data trace. Also looks just like my RRC3 data traces when I have an unintended main-at-apogee event in dual deploy birds. I have a Mad Cow 4" DX3 that took 4 flights before I got the magic set up on it where dual deploy worked every time without shaking the main out before the intended altitude.
 

jbrracer

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jbrracer

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Looks like a typical nominal single deploy data trace. Also looks just like my RRC3 data traces when I have an unintended main-at-apogee event in dual deploy birds. I have a Mad Cow 4" DX3 that took 4 flights before I got the magic set up on it where dual deploy worked every time without shaking the main out before the intended altitude.

Is Main at apogee that common?
This is the same Ebay that ive flown a hand full of times DD without issue...
 

timbucktoo

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Is Main at apogee that common?
This is the same Ebay that ive flown a hand full of times DD without issue...
Only if you planned it that way. Otherwise something wrong with your setup.. Drogue harness too short? No NC retention (shear pins)? Overaggressive drogue charge?
 

Charles_McG

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The altitude ramps up like you'd expect, then drops down almost to zero, then rushes back up a reasonable ascent curve. The velocity is just the 1st derivative of the altitude, so it highlights the slope. The unfiltered data is the same, so that broad dip is something broad in time, not a single big jolt being smoothed by the filtering process. If it were a jolt, I say something shifted, or blew off in flight. It's not at the right speed for a mach issue. For the altitude to drop, it means the pressure must be going up - so where could that come from: motor leakage forward, short of failure, a early deployment charge short of popping the nosecone (but I'd expect that to be narrower), or maybe a quirk of your nosecone or avbay design that is funneling airflow in to the avbay (but I'd expect that to be a function(velocity) and it doesn't look like that to me.)
 

heada

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The raw data of the TRS feed says main should have happened at 1000ft and drogue at apogee.

Eggtimer TRS 2.10 Flight Settings
...Drogue <1=Normal,2=Backup,0=OFF>...1
...Main Alt <50-2000 by 50, 0=OFF>...1000

Then you can see LDA (Launch Detect Alt) is at 211 ft at 1.25 seconds

LDA: 211 ft
Time @ LDA:1.250

Apogee happened at 6612 ft at 17.95 seconds

Apogee: 6612 ft
T @ Apogee: 17.950

Altitude at N-O (Nose over) 6416 ft and at 18.95 seconds

Alt @ N-O: 6416 ft
T @ N-O: 18.950

Nose-over is when the apogee charge was fired (1 second after apogee). I'm not sure if you had a tail slide or something else at apogee that delayed the nose-over by a second or if the normal config is a 1 second delay, the user manual should state what the "normal" config is.

Alt @ Drogue: 6416 ft
T @ Drogue: 18.950

The main charge fired at 988 ft and at 195.95 seconds

Alt @ Main: 988 ft
T @ Main: 195.950

Now, based on your decent rate, either your drogue was too large or the main popped at apogee too which can happen if it doesn't have sheer pins or is too loose. The charge fired at the right time and altitude but it could have fired into an empty body tube if your main was already out.
 

heada

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The altitude ramps up like you'd expect, then drops down almost to zero, then rushes back up a reasonable ascent curve. The velocity is just the 1st derivative of the altitude, so it highlights the slope. The unfiltered data is the same, so that broad dip is something broad in time, not a single big jolt being smoothed by the filtering process. If it were a jolt, I say something shifted, or blew off in flight. It's not at the right speed for a mach issue. For the altitude to drop, it means the pressure must be going up - so where could that come from: motor leakage forward, short of failure, a early deployment charge short of popping the nosecone (but I'd expect that to be narrower), or maybe a quirk of your nosecone or avbay design that is funneling airflow in to the avbay (but I'd expect that to be a function(velocity) and it doesn't look like that to me.)
Could a very strong gust of wind into the av-bay account for the pressure spike? Neither charges were fired until well into the flight and if the motor started to leak, I'd expect a very different altitude plot.
 

Charles_McG

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I'd expect strong weather cocking at the same time, if it climbed through a strong wind shear layer. And isn't that why you have 3-4 vent holes? We don't have the sim export data to compare, which might help.

I've built avbays with vented attachment pins. I had a small plastic part handy and it seemed like a good idea. But the domed top of the pin make a low pressure zone as the air flows over it. That makes an error in the other direction - a false high altitude. And it varies with velocity. It's easy to show with the data from a Proton, with both baro and accelerometer data.

A glitch that lasts 350ms is harder to explain. And drops the baro from 400' to 50'
 

heada

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There is a big pressure anomaly from 1.6 seconds until about 2.6 seconds where it appears to get stable again. Drogue didn't fire until 18.95 seconds and main fired at 196 seconds so it can't be from either charge. The rest of the flight looks nominal so I don't think it was an issue with the motor or you'd see cartwheeling or something similar.

I'm thinking it was a level of wind sheer or similar from 300' to 350'/400' that played havoc with the pressure sensor.
 

Banzai88

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I'd say you had a motor event that pressurized your avbay, but fell short of a CATO.
View attachment 438658
Interesting theory, but I would think it strange that it would have enough blow-by pressure to spike the av bay, but not enough to separate the rocket prior to apogee and have a flight failure.

Was this a CTI motor? The 54s are known to blow-by the fwd o-ring, and it seems that more and more reports of it happening with the 38s are becoming common place, too (I've had 2 happen last year myself before learning about gluing the fwd closure).

@jbrracer, is there a shear pin/pins holding the av bay to the booster fin can? How long is the recovery harness from the fin can to the av bay? If there were a blow-by puff that resealed, you got very very lucky.

You say that you've flown this av bay before, but has it been in this same rocket? The whole bay or just the avionics sled?

Was a motor delay used as backup to the apogee separation charge? It's entirely possible that variance in the delay blew the motor ejection charge at the same time that the avionics charge went off, causing a massive pressure spike that blasted the forward section hard enough against the recovery harness that the nose shook off and you had an un-commanded deployment of the main-at-apogee. Regardless, the descent data looks like the main came out at the top instead of 1K feet like you planned.
 
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heada

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Was this a CTI motor? The 54s are known to blow-by the fwd o-ring, and it seems that more and more reports of it happening with the 38s are becoming common place, too (I've had 2 happen last year myself before learning about gluing the fwd closure).
Based on another post, it was a 54mm AT K540
 

Banzai88

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Based on another post, it was a 54mm AT K540
OK, that rules out CTI forward closure blow-by issues causing an ebay pressure spike for the early flight anomaly. I would think that in an AT motor, such a failure would otherwise be catastrophically kinetic based on the case design.
 

Charles_McG

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If this indeed was the flight from the locked thread, then it was an AT K540 metalstorm. A 3 second burn, so the T+1.85sec anomaly doesn't line up with motor burnout.

Something happened. A blow-by puff seems unlikely. As does a premature - but weak - deployment charge. And I would think a string wind shear would weathercock the rocket.

So, I don't know. it's a curiosity.

Was the main sitting on a piston that could have suddenly shifted down under thrust?
 

jbrracer

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Only if you planned it that way. Otherwise something wrong with your setup.. Drogue harness too short? No NC retention (shear pins)? Overaggressive drogue charge?
I’m guessing you’re on the right track nose cone came off at drogue deployment. No shear pins and probably not tight enough. I ground tested shear pins with no luck just bent and pulled them. 1.1 charge drogue and main.
 

Banzai88

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That early pressure spike anomaly aside, the fact that the rocket continued to apogee after that seems to contraindicate that it was the trigger event that caused early release of the main parachute, as evidenced by the descent curve.
 

jbrracer

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If this indeed was the flight from the locked thread, then it was an AT K540 metalstorm. A 3 second burn, so the T+1.85sec anomaly doesn't line up with motor burnout.

Something happened. A blow-by puff seems unlikely. As does a premature - but weak - deployment charge. And I would think a string wind shear would weathercock the rocket.

So, I don't know. it's a curiosity.

Was the main sitting on a piston that could have suddenly shifted down under thrust?
Wouldn’t the dip / downward spike equate to high pressure inside the eBay?
 

Charles_McG

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I’m guessing you’re on the right track nose cone came off at drogue deployment. No shear pins and probably not tight enough. I ground tested shear pins with no luck just bent and pulled them. 1.1 charge drogue and main.
That sounds likely to be the cause of the main-at-apogee. If the payload reached the end of its harness with enough momentum to pop the nosecone, that's what you'd get.
 

jbrracer

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If this indeed was the flight from the locked thread, then it was an AT K540 metalstorm. A 3 second burn, so the T+1.85sec anomaly doesn't line up with motor burnout.

Something happened. A blow-by puff seems unlikely. As does a premature - but weak - deployment charge. And I would think a string wind shear would weathercock the rocket.

So, I don't know. it's a curiosity.

Was the main sitting on a piston that could have suddenly shifted down under thrust?
And if it weather cocked you would see a less linear altitude graph right?
 
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