Water Rocket Calculator

Launch Gauge Air Pressure		psi
PreLaunch Tank Air Volume		liters
Nozzle Diameter		cm
Rocket Diameter		cm
Mass of Empty Rocket		grams
Volume of Empty Fuel Tank		liters
Air Friction Constant		-
Air Friction Velocity Exponent		-
Air Density		lb/ft³
Barometric Pressure		hPascal

Burnout Time		sec
Burnout Velocity		m/sec
Burnout Height		meters
Average Blastoff Acceleration		m/sec²
Maximum Blastoff Acceleration		m/sec²
Max Rocket Altitude		meters
Time to Max Altitude		sec
Select Data Paste data into a MS Excel spreadsheet Column
FLIGHT LOG

This calculation is based on an algorithm and formulas in the March 1995 Physics Teacher, Volume 33, Number 3, p 150-157: Soda-Bottle Water Rockets by David Kagan, Louis Buchholtz and Lynda Klein. Note that for small values of "Launch Gauge Pressure", the calculation may use the square root of a negative number - a "NaN" (not-a-number) to the Javascript interpreter. Just raise the pressure value and this problem should go away.

This model was modified to include friction effects using:

F=0.5*c*d*A*v^K
where:

c = Friction constant of surrounding fluid (depends of object shape)
d = Density of surrounding fluid
A = Area of rocket cross section
v = Rocket velocity
K = Velocity exponent