Another Jolly Logic CR question...

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ouisconsin rocket

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Making the assumption that the JLCR works on a baro sensor, how does it, or does it. ignore the overpressure from the deployment charge when measuring descent?

Am I correct to assume it measures pressure when turned on at the launch rail.

(I know most of the "assume" jokes)
 
I believe it's the Magic imparted by Mr Beans.

Or software programming that ignores barometric pressure spikes. Just like most altimeters that program the software for "mach lock out" and filter out unwanted noise.
 
I believe it's the Magic imparted by Mr Beans.

Or software programming that ignores barometric pressure spikes. Just like most altimeters that program the software for "mach lock out" and filter out unwanted noise.


I can accept the magic part. Most things that I don't completely grasp (and there are a lot of those) I attribute to magic or in a block diagram "something happens here".

Thanks Eric
 
It really doesn't have to be anything 'magic', remember that pressure decreases at higher altitudes, and increases with an ejection charge. So the two events are in opposite directions. When my A2/A3 is in a part of the rocket that will see an ejection charge the charge shows on the graph, as a sharp negative altitude spike. But apogee will be the part where the graph levels-off between ascent and descent. So if the charge occurred exactly at apogee you might get a dip where the peak of the curve would have been, but since the rocket's altitude change is relatively small at that point it shouldn't impact the apogee reading by more than a few feet I'd think.

But yes, it should be taking pressure readings from the moment you hit Record in the app until it considers itself landed. I think it might use its accelerometer for launch detect, though I'm not certain, I've had a few flights recorded as ~100ft and only a few seconds long because it considered launch and landing to have occurred before the rocket ever left the rail, not sure if it was because of a wind gust or some other shock to the rail (or maybe loading the ignitor).
 
Will.....they're talking about a Chute Release. No accelerometers and no app. But your points about the pressure profile are spot on.

Also, the CR is looking for the set altitude by approaching it from above. I'm sure there is filtering for spikes and other such things in the software magic that has been well honed on use in A1/A2/A3 over the years.
 
It really doesn't have to be anything 'magic', remember that pressure decreases at higher altitudes, and increases with an ejection charge. So the two events are in opposite directions. When my A2/A3 is in a part of the rocket that will see an ejection charge the charge shows on the graph, as a sharp negative altitude spike. But apogee will be the part where the graph levels-off between ascent and descent. So if the charge occurred exactly at apogee you might get a dip where the peak of the curve would have been, but since the rocket's altitude change is relatively small at that point it shouldn't impact the apogee reading by more than a few feet I'd think.

But yes, it should be taking pressure readings from the moment you hit Record in the app until it considers itself landed. I think it might use its accelerometer for launch detect, though I'm not certain, I've had a few flights recorded as ~100ft and only a few seconds long because it considered launch and landing to have occurred before the rocket ever left the rail, not sure if it was because of a wind gust or some other shock to the rail (or maybe loading the ignitor).


Woferry,

Thx for your reply. Your information was posted in a manner that even my feeble mind can understand. Thanx

Paul
 
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