An aperture on top of the parachute or left blank by a gore to ensure stability in the descent. A vent also can be opened on the back of a round canopy to allow air to escape and thus propel the parachute forward approximately 3 to 5 miles per hour. This allows a small amount of steerability in a round canopy. See parachute.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved