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One of several small auxiliary gasbags placed inside a balloon or a nonrigid airship that can be inflated or deflated during flight to control and maintain shape and buoyancy.

[French ballonnet, diminutive of ballon, balloon; see balloon.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Aeronautics) an air or gas compartment in a balloon or nonrigid airship, used to control buoyancy and shape
[C20: from French ballonnet a little balloon]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˌbæl əˈneɪ)

an air or gasbag compartment in a balloon or airship used to control buoyancy and shape.
[1900–05; < French]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
It uses the existing ballonet fans to inflate and takes under 20 seconds to be ready for use.
To this end, Loon uses balloons that are in fact composed of two envelopes: an outer balloon which contains helium to generate the lift to take it into the stratosphere, and an inner balloon (or ballonet) which can take in or release air in order to modify the altitude once aloft.
A classical airship has various configurations: flabby balloon with ballonet (air chamber), partially inflated and fully inflated (Figure 5).
Inside the envelope are two bags of air known as ballonets. Instead of the engine, these ballonets are inflated with helium gas that lifts the blimp into the air or deflated to bring it down.
As a result, before initial departure from home station the amount of air in the ballonets would have to be adjusted to 325 tons of aerostatic lift even if the total gross weight of the vehicle at the time was several times that with cargo and fuel load.