Freefall Drift Simulator

Written by Dave "Juggler" Blumenthal and John Kallend. For more information about this simulator, please see the technical information page. For more resources on freefall drift, please see John Kallend's skydiving collection.

John and I wrote these simulators to help skydivers understand what is happening in the air and how to be safe. If you have any comments about this site, feel free to email me at poijuggler (at) gmail (dot) com.

Instructions

This program simulates the most likely trajectories of groups of skydivers in freefall with different fall rates, given the fall rates, airplane speed, and winds. It requires the Hypercosm 3D Player, which is unfortunately no longer available (Hypercosm is out of business). If you don't already have it, you are out of luck. Go to John Kallend's version.

In the "World" view, click and drag to view the scene from different angles. Click on "Reset View" to return to the default viewing angle. Click on "Run Simulation" to reset the simulation and run it again.

Click on "Show Instruments" to view the controls. Here, you can adjust the fallrates of the two groups of skydivers, the separation between exits, and the speeds of the winds at different altitudes and of the airplane. For example, you can switch the freefall speeds of the two groups and see what happens when freeflyers exit before RW groups. For more details on these adjustments, read the technical information page. Click on the "Run" button at the bottom to return to the world view.

Scroll down to the bottom of this web page to see the results of the simulation.

This applet requires the Hypercosm 3D Player, which is no longer available.

Simulation Results Simulation time: seconds
Group 1 Opening point: feet north of spot
Group 1 Freefall time: seconds
Group 2 Opening point: feet north of spot
Group 2 Freefall time: seconds
Horizontal separation between exit points: feet
Horizontal separation between opening areas: feet
Horizontal separation now: feet
A horizontal separation value of zero indicates a potential for collision on opening. For better safety with today's fast parachutes, the horizontal separation when the simulation ends should be at least 300 feet.
Copyright 2001 David Blumenthal. All Rights Reserved. Portions Copyright 1999 John Kallend. Portions Copyright 2000 Hypercosm, Inc.