Re: 737 tail question

Date:         15 Apr 97 12:56:43 
From:         ehahn@mitre.org (Edward Hahn)
Organization: The MITRE Corporation
References:   1
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In article <airliners.1997.938@ohare.Chicago.COM>, "Hans Jakobsson"
<hansj@algonet.se> wrote:
>sometimes I've seen a row of dark pins sticking out of the fuselage on
>737-200s. The pins (or nails) are placed in a neat row on each side of the
>fin, between the stabilizer and fin root. It seems that they are retracted
>into the fuselage when the aircraft is flying. What are these?

I'm assuming you're seeing vortex generators, which are actually thin "tabs"
sticking off the fuselage, rather than pins or nails.  Their purpose is to
keep the airflow from separating off the aft body & horizontal stabilizer, by
adding energy to the boundary layer (at the cost of a small amount of extra
drag.)

Vortex generators are used in a variety of places on a lot of modern
transports.  They are most notable, for example, on the top surface of the
B737 wing.

They aren't retractable, either.

ed

>>>>  Ed Hahn    |    ehahn@mitre.org    |    (703) 883-5988  <<<<
The above statement is the opinion of the author.  No endorsement
or warranty by the MITRE Corporation is expressed or implied.
Really, I wouldn't kid you about a thing like this.