how to work out G forces using altimeter!

[TDFwaterrockets]

To work out the G forces at launch using and altimeter is actually quite easy. If you download the altimeter data as a graph then it should show you the time VS altitude. All you have to do is work out the top speed and how long it took for the rocket to reach that speed. for example:

If a rocket went from 0m/s to 200m/s in 0.5 seconds, then you go to google homepage and type in the search bar: 200m/s/0.5s=?g

The number in yellow is the speed and the number in red is the time it took to reach that speed. then when you click search, something like this should appear... (200 (m / s)) / (0.5 s) = 40.7886485 g

The answer in blue is the G force!

Please comment if this is too confusing!


TDFwaterrockets
http://tdfwaterrockets.blogspot.com/

[dongfang]

Hi,

Nice idea! You can get inexpensive accelerometers too, and rig them to a data logger in the same way as with a pressure sensor.

200 m/s for a water rocket, that's impressive ;) Improve a little on that, and you will go supersonic, haha

Regards
Soren

[TDFwaterrockets]

hi Soren

My fastest rocket to date had a top speed of 220f/t (67m/s) but I put 200m/s on the post because its metric and its only an example...

TDFwaterrockets
http://tdfwaterrockets.blogspot.com/

[Tim Chen]

Hi guys! "g"-forces are really just a measure of acceleration, which is the rate of change of velocity of an object. (Delta v over Delta t) If your car accelerates from 0-60MPH in 6 seconds, it has an acceleration of 4.3 meters/second per second. Which means every second the speed is increased by 4.3 meters.

You must compare this acceleration to the acceleration produced by the gravity of earth if you want to see the answer in "g". The earth has a gravity acceleration of 9.8 meters/second per second. (This means if you drop an object it will increase in speed by 9.8 meters/second every second as it falls if you ignore air friction)

If you compare the car to the earth you will see that 4.3/9.8 (the units cancel out) = 0.44

A "g" can be thought of as a unit of acceleration whose value is 9.8 m/s^2.

So in the end your car is accelerating at about 0.44 times gravity, or 0.44 g's.