I just got the Jolly Logic AltimeterTwo from Amazon.com for $69.99. I used it today and it is, as advertised, a great and fun product for Model Rocketry. This second generation device “uses state-of-the-art pressure and acceleration sensors to perform the 10 most important flight analyses for each rocket flight”.
I attached a cord and swivel to mine to attach it inside the rockets. The Lithium Polymer battery comes fully charged, and with a USB charging cable. It has a easily readable screen that scrolls your flight results. It can store up to 100 flights. You can choose between feet and meters.
My Custom Equinox parachute did not deploy, the nose cone ejected, but the body tube (and AltimeterTwo), lawn darted. The rugged ABS construction case partially came open but after we took it apart (super easy), adjusted the inner workings and re-snapped the case closed, it worked perfectly.
The AltimeterTwo is very small, measuring 0.6 x 0.7 x 0.2-inches, so it will fit in pretty small rockets. It is approved for use in official contests, too. The data it captures and displays instantly for each flight is:
Coast to Apogee
Apogee to Ejection
Total Flight Duration
I highly recommend the Jolly Logic AltimeterTwo for your Model Rocketry flights. It will help you adjust your recovery sizes and your ejection charge selection. Oh yeah, it’s a lot of fun just to know the altitude and speed of your rocket flights!