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SpaceManMat

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Yeah, I wanted to do a flight with the fix that proves I have actually solved the problem, so to be safe I’m after a setting to make sure a reoccurrence does not result in another early deployment.

I’ve gone over the configuration settings and came up with the following 3 solutions.

Option 1 - Lower the Mach lockout setting. I checked over my previous Raven flights and apogee typically occurs less than 50 feet/s, this flight peaked at around 230 feet/s. This should delay deployment until well past burnout and with the rocket well into the coast phase, at this stage the decaying speed should allow the pressure to start decreasing (this appears to have actually started in the previous flight but not soon enough to affect the altimeter logic)

Featherweight - Altitude Lockout
on Flickr

Option 2 - Altitude Lockout. I like the idea of this setting as it would be of no real consequence on pretty much any flight (deployment below 32 feet is not usually going to be successful) but if something weird happens with the ave bay being pressurised then it should hopefully save the day.

Featherweight - Altitude Lockout
on Flickr

Option 3 - Time Lockout. The idea here is to wait about a second after burnout before enabling baro deployment, this should be reasonably safe with apogee occurring about 1.5 seconds after this.
I have to ask, for the Main and 4th channel why does the default setting use both Flight Time < TVal and Flight Time > TVal, how does that work?

Featherweight - Time Lockout
on Flickr

I think without having a full flight of data to see how this anomaly would end, that the safest option is going to be the velocity lockout. I think this is the least likely to cause an issue over a variety of failures with this motor and rocket combination. There’s always the backup channel if this setting is too restrictive.

Thoughts?
 

manixFan

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How do you read FIPa files? Noob here...
The files are produced by the Featherweight Raven altimeters and use FIP:



Tony
 
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blindner

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Is there a way to export FIP files into a csv to be better read by a python or c program?
 

Buckeye

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Is there a way to export FIP files into a csv to be better read by a python or c program?
Yes. In the plotter of the FIP, you can right click on a curve to export to file. Something like that...
 

manixFan

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Is there a way to export FIP files into a csv to be better read by a python or c program?
In the Parameter Selection window:
  • select the variables you want to export (hold down the control key to select multiple values)
  • right click over the Parameter Selection window and choose "Save Data > Time Paired"
That will create a CSV file with several paired columns, the first column in a pair being the flight time and the second column the variable value. One issue that throws users is that not all the sensors are sampled at the same rate, so you can't just use the time from the first column for the remaining variables. So that does require some work to standardize all the values.

If you choose 'Flattened", it creates a single column for the time value and then a column for each variable. Again, because of the varying sample rates, this will cause some columns to have several rows of duplicate values.

If you come up with another form of data-reduction other than the FIP software, please let us know.

Good luck,


Tony

(if you right-click on a graph, you only get the option to copy the graph, so Buckeye's instructions are not correct)
 
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blindner

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Trying to figure out my reference frame here. Axial Accel measured in G's doesn't make sense. Shouldnt axial accel be measured in rad/s/s? Also there is only one lateral accel, so is that +x/-x accel? Also (sorry lol) why does all velocity data in all the flights I've been looking at end at apogee? Just confused on where all the measurements are referring to.
 

Buckeye

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Trying to figure out my reference frame here. Axial Accel measured in G's doesn't make sense. Shouldnt axial accel be measured in rad/s/s? Also there is only one lateral accel, so is that +x/-x accel? Also (sorry lol) why does all velocity data in all the flights I've been looking at end at apogee? Just confused on where all the measurements are referring to.
Axial is the long direction of the acclerometer board, usually oriented with the length of the rocket. Lateral is perpendicular to the axial, probably in the same plane as the acclerometer board.

Velocity integrated from accel ends at apogee. After that, the accel data is usually meaningless as the rocket arcs over, ejects, tumbles, sways, etc. If you want data after apogee, look at the baro.
 
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