strap arduino to Pitsco Aquaport Rocket...need assistance

For my Force and Motion Unit, we are having students design water bottle rockets (2L) for the Pitsco Aquaport Rocket Launcher. We would like to strap arduinos to the Rockets. http://www.pitsco.com/Aquaport_II_Water_Rocket_Launcher

We have found a good altimeter http://www.instructables.com/id/The-Ultimate-Altimeter-A-compact-Arduino-altimeter/

However, we would also like the students to be able to create a hang time stopwatch; speedometer; and forcemeter as well, so we can crunch a bunch of data.

The hang time stopwatch seems to be the most difficult to figure out, as we want it to begin as soon as the rocket is launched and stop as soon as it hits the ground. Ideally, we would like it to start at launch, then when the rocket hits its apex, take a time measurement; then give us a second time measurement when it hits the ground, so we can compare the force of the water pressure versus the force of gravity.

A speedometer and forcemeter would be icing on the cake.

Any assistance would be greatly appreciated.

I’d take data as fast as I could during flight with an accelerometer (there are many choices) and crunch numbers afterwards. Gives you material to make a nice little graph too and all.

Seems like hangtime would be easiest - capture the time, maybe store in EEPROM, when you first see a big change in acceleration (the launch) and again at the next big change (the landing).
Speedometer, that's hard as you don't know distance travelled. Can add a barometer for elevation, numbers will be good if going more or less straight up, capture/save the time when acceleration goes from + to 0, then can calculate average speed.

Aren't there model rocket boards that do all this already?

Google "model rocket telemetry", "model rocket telemetry package", "model rocket telemetry arduino" for interesting sites.

Why do you want to strap the device to the launcher?
Don't you want to strap it to the rocket?

AWOL:
Why do you want to strap the device to the launcher?
Don't you want to strap it to the rocket?

Yes, we would strap it to the rocket.

CrossRoads:
Google “model rocket telemetry”, “model rocket telemetry package”, “model rocket telemetry arduino” for interesting sites.

That was very helpful. Thank you!