Screwy Jolly Logic Altimeter 2 data

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Zeus-cat

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So I flew my Altimeter2 three weeks ago and then a few days ago. No other flights for Alt2 in between. Same rocket used for both flights. I secured the Alt2 inside the av bay with zip ties to a cradle for the Alt2 in the same location for both flights. Alt2 was fully charged before the November 11th flight. Now reading 89% power. I cleared the Alt2 memory between flights. The data for November 11th looks good and is darn close to the Stratologger data. The data for December is bizarre. I am tempted to treat it as a one time glitch. It will be another week and half before I can fly it again. Anybody else have a similar problem?

11/11/17
Loc Iris
H242 dual deploy
Stratologger
Apogee: 1,277
Top Speed: 217 mph
Flight Duration: approximately 48 seconds

Jolly Logic Altimeter2
Apogee: 1,279
Top Speed: 209 mph
Burn Time: 1.13 seconds
Peak Accel: 10.7 G
Avg. Accel: 8.5 G
Coast to Apogee: 7.9 seconds
Apogee to Eject: -0.3 seconds
Ejection Altitude: 1,277 feet
Descent Speed: 22 mph
Flight Duration: 46.3 seconds


12/2/17
Loc Iris
I284 dual deploy
Stratologger
Apogee: 1,277
Top Speed: 408 mph
Flight Duration: approximately 106 seconds

Jolly Logic Altimeter2
Apogee: 4 feet
Top Speed: 58,404 mph (Mach 84?)
Burn Time: 0.42 seconds
Peak Accel: 0.1 G
Avg. Accel: 6,279 G
Coast to Apogee: 6.4 seconds
Apogee to Eject: -6.3 seconds
Ejection Altitude: 1 foot
Descent Speed: 0 mph
Flight Duration: 6.8 seconds
 
It's a false launch. It uses its accelerometer to sense launch (pressure can lag tremendously, acceleration is instantaneous). One accidental shake became the boost, another became ejection, it was always at ground level (that's the 1 and 4 feet marks). All of the data is just nonsense at that point. It missed the actual launch after that.

The logic tries to ignore handling, but there are limits. Just the right amplitude/duration/pattern of knocks or bumps can do it. In order to capture the launch properly and work for all rockets, it has to be a little sensitive.

Hope that all makes sense. The solution is to check for "Ready" on the pad if you can and be delicate closing it up. You can arm it at your table, but then you just have to handle it gingerly. No dropping it down the rail or anything.
 
John already posted here, so I will jump in and say John replied directly to me via email after I sent him the data. He replied in less than an hour. Great job John and thanks for the explanation. I'll be more careful handling the rocket in the future. As I explained to John the Alt2 was in the av bay, so it was on for 30-45 minutes prior to launch as I finished prep, built the motor, had the rocket safety checked and then carried it out to the pad.

Great product and great support from Mr. Beans!
 
I never sealed my AltimeterTwo in a bay, it was always attached to the nose tether, or somewhere I could easily open at the pad, set to Launch and then close up with minimal disturbance to the rocket. If you have to seal it in something back at your table, I'd strongly recommend the AltimeterThree, which you can power-up earlier, and then not actually set to Record (done remotely via bluetooth) until you're loaded on the pad and ready to fly (just don't forget to arm it!) :)
 
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