For rocket team last spring we used the calculations from this site - http://www.rocketmime.com/rockets/descent.htmlCookiePie1 wrote: ↑January 21st, 2020, 7:34 pmSorry, but how did you calculate this? and, theory tends to be quite different than practice in build events, especially one as complicated as parachutes.
If you scroll down on that page you can use the red calculation for velocity: v = sqrt( (8 m g) / (p r Cd D2) )
D is the chute diameter in meters
m is the rocket mass in kilograms
g is the acceleration of gravity = 9.8 m/s2
p is 3.14159265359
r is the density of air = 1.22 kg/m3
Cd is the drag coefficient of the chute, which is 0.75 for a parasheet (flat sheet used for a parachute, like Estes rockets), or 1.5 for a parachute (true dome-shaped chute).
v is the speed we want at impact with the ground (3 m/s or less)
You just need to multiply the v which is in meters/sec by 3.281 to get Feet per second. If the claims are true you need .5 ft/sec in this calculation.
I know there are some people flying outside - and who knows what that means for times. And some of the gyms I've been in feel like a tornado - so maybe you can catch an updraft. It's also a bit hard to estimate height in the gym or exactly how high the rocket went on a launch, so there might be some error in reported numbers because of that. But to get .5 on this calculation you need to be around 2 meters and 5 grams unless you can build a super light dome shape (real) parachute and then you still need 1.5M.