Craig Klimczak <[email protected]> writes: > Your're right. :-) I really don't understand what the > accelerometers are reporting. I assumed that the accel would detect > the de-acceleration as the rocket reached apogee, reach a point of > zero acceleration and then start accelerating back toward Earth.
Uh. You're still missing something. After motor burnout, save for the effect of air resistance, the rocket spends the entire flight accelerating at 1g towards earth. You may want to consider a bit of a refresher on newtonian physics :-) > how do you estimate apogee by acceleration alone? We assume the rocket is pointing upwards during ascent and integrate the z-axis acceleration to compute change in speed. If we assume the rocket starts at rest, then when the total change in speed gets us back to zero, then we've stopped moving in that axis. This is slightly complicated by gravity -- when the accelerometer measures zero acceleration, we're actually accelerating towards the ground at 1g, so we add 1g of acceleration to whatever the accelerometer measures. Don't expect TeleMega to work on the moon. -- -keith
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