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Path: utzoo!mnetor!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!uw-june!uw-entropy!dataio!bright
From: bright@Data-IO.COM (Walter Bright)
Newsgroups: rec.aviation,comp.graphics
Subject: Re: JAL 747 crash film (what's a Dutch Roll?)
Message-ID: <1541@dataio.Data-IO.COM>
Date: 9 May 88 17:56:36 GMT
References: <7237@mhuxd.UUCP> <778@scubed.UUCP>
Reply-To: bright@dataio.Data-IO.COM (Walter Bright)
Organization: Data I/O Corporation; Redmond, WA
Lines: 20

In article <778@scubed.UUCP> rankin@s3mickey.UUCP (Tom Rankin) writes:
>In article <7237@mhuxd.UUCP> wolit@mhuxd.UUCP (Jan Wolitzky) writes:
>>...The Dutch rolls performed by the plane after losing most of its 
>What, pray tell, is a Dutch Roll?...no relation to a Danish, I
>presume :-).  Inquiring minds want to know.

Dutch roll occurs when you have yaw instability. (The three axes of
rotation are pitch [nose up/down], roll [wing up/down] and yaw
[nose left/right].) With yaw instability (common when you lose the
rudder!), the tail moves side to side. This causes the left/right wings
to have more/less lift, which adds an element of roll and pitch. The net
result is the plane traces a corkscrew path. The effect I am told can be
quite sickening to the passengers.

The last episode of "Test Pilot" on PBS showed a wonderful film of
a plane doing a dutch roll.

By the way, Dutch people are from Holland! The word dutch is a
corruption of 'Deutsch', which means German. Somehow it got
misapplied to people from the Netherlands.