Essence's Model Rocketry Reviews & Resources (EMRR)

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Jack Anderson's Descent Rate Calculator

This page uses VBScript so you must be using Microsoft Internet Explorer, Netscape just can't do it !

How fast will my rocket hit the ground with this parachute(s)?

Weight of rocket with motor hardware but no propellant.
You can find the motor hardware weight here (link no longer exists).
Diameter of main parachute in inches
Use zero if you are not using chute # 2 or #3
Diameter of parachute #2 or drogue in inches
Diameter of parachute #3 in inches
Launch site elevation

Type of Parachute(s) Assumes all parachutes used are the same type.
Round Hemispherical X-Form

This rocket should hit the ground at feet per second.

A good rule of thumb is that your rocket should hit the ground at 15 feet per second. A well built rocket could withstand as much as 20 feet per second. To give you a little perspective, 16.4 feet per second would be the same as dropping your rocket from 4 feet with no parachute. To calculate how big your drogue chute should be, put in the diameter you are considering into the main parachute diameter input box. A good rule of thumb for drogue chutes is 50 feet per second. Once you have calculated your descent rates, you can use my drift calculator to see how far you will have to go to recover this rocket.

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