Motor Ejection and DD altimeter

[Handeman]

If you have a 39/360 case, the I161W-M might be a good choice. I don't know how heavy your rocket is, but at 4 lbs. w/o motor it should get about 2500 ft. At 5 lbs w/o motor it should reach about 1900 ft.

Good Luck

 

[Adrian A]

Here's some a graph that shows what an accelerometer measures in flight. A mercury switch reacts the same, except it just switches on or off depending on whether the measured acceleration is positive or negative. The only time before deployment the measured acceleration crosses zero is at burnout. You can see that the velocity, drag, and resulting negative acceleration were starting to go up again in the second between apogee and the deployment.

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