What accelerometer to buy?

I'm looking at various accelerometers to add more stuff to fail on my Arduino, but one thing's been bugging me- How many Gs does the average MPR/low HPR flight see? I wanna get a 16G one, mainly because it has i2c like my Baro, so I can hook them all up on the same bus, but I can also get up to a 250G altimeter. Will 16 gs be good?

Rocksim will tell you. 70 Gs covers everything but Vmax or Warp-9 loads on small rockets, which can go over 100 Gs. 30 Gs covers most flights with typical propellants.

Dr. Quigley said:

I'm looking at various accelerometers to add more stuff to fail on my Arduino, but one thing's been bugging me- How many Gs does the average MPR/low HPR flight see? I wanna get a 16G one, mainly because it has i2c like my Baro, so I can hook them all up on the same bus, but I can also get up to a 250G altimeter. Will 16 gs be good?

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To add to what Adrian said, 25 to 30 g is probably a good range to find.
If you go from 30 g to 250 g your going to loose a ton of range. The lower the g rating, the better change rate your going to get... this means picking up a cleaner acceloration curve, and little more accuracy.

Mid power with an adruno board will have a hard time pushing 30 g's the smaller H motors would still have to be small and light to hit 30 g.

Most the time my flights are 15 to 20 g, but i have heavy stuff too....

Sparkfun has a breakout board for the ST-LIS331HH, which is the 24G x 3-axis accelerometer that the Jolly Logic AltimeterTwo uses, also via I2C.
Should high-Gs be more important than build complexity, you can align it cleverly (i.e. not orthagonally) and coax more effective Gs out of it in a particular direction--up to about 40Gs above gravity.

Breakout board: here
Article on angling for more Gs in a specific direction: here

--John

Thanks! That's exactly what I'm looking for!