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From: dbr@odin.UUCP
Newsgroups: net.aviation
Subject: Contra-Rotating Propellors
Message-ID: <329@odin.UUCP>
Date: Tue, 9-Oct-84 15:04:27 EDT
Article-I.D.: odin.329
Posted: Tue Oct  9 15:04:27 1984
Date-Received: Wed, 10-Oct-84 05:01:08 EDT
Organization: AT&T Information Systems, Holmdel NJ
Lines: 6

The two closely spaced propellors act as one device.
Ideally, the rear propellor straightens out the swirling
airflow from the front, improving the overall efficiency.
One early use of contra-rotating propellors, and still
used, is naval torpedoes.
The Russian Tu20 has 4 contra-rotating turboprops.