From: Joseph F Baugher <jfb@ihlpl.att.com>
Subject: Ninth in the Series--The Boeing XP-9
Keywords: Boeing's first monoplane fighter
Organization: AT&T Bell Laboratories -  Naperville, Illinois
Date: Tue, 1 Sep 1992 13:36:47 GMT


From Joseph F Baugher <jfb@ihlpl.att.com>


The XP-9 was Boeing's first monoplane  fighter  design.   Bearing  the
company  designation  Model  96, it was designed to Army Specification
X-1623A which was issued on May 24, 1928.  The Model 96 was designated
XP-9 by the Army when a contract for one example was signed on May 29,
1928.  The serial number was 28-386.  The XP-9 was actually the  first
Boeing  monoplane  to  start  through  the factory, but various delays
postponed the delivery date from April 1929 to September 1930,  so  it
was  not the first actually to fly, having been beaten into the air by
the new Model 200 Monomail.

The construction of the XP-9 was entirely new to Boeing.  The fuselage
was  a  semi-monocoque structure of sheet dural over metal formers for
the portion aft of the rear  undercarriage  struts  and  welded  steel
tubing  from  that  point forward to the engine.  The tail surfaces of
the XP-9 were identical to those of the  contemporary  P-12/F4B.   The
shoulder-mounted,  externally-braced monoplane wing had a conventional
two-spar structure with a metal framework and fabric covering.   Power
was  supplied  by  a 600 hp Curtiss SV-1570-15 Conqueror liquid-cooled
engine with supercharging. A chin-type radiator was mounted underneath
the  engine.   A  0.50-cal machine gun was mounted on each side of the
fuselage,  firing  through  tunnels  mounted  just  below  the  engine
cylinder blocks.  In addition, two 122-lb or five 25-lb bombs could be
carried.

Upon completion, the XP-9 was delivered  by  rail  to  the  Army  Test
Centre  at  Wright  Field.  It made its first flight there on November
18,  1930.   Flight  tests  of  the  XP-9  by  the  Army  were  rather
disappointing.   Visibility  from the cockpit was extremely poor.  The
plane suffered  with  such  a  large  number  of  serious  instability
problems that it frightened even the most experienced Army pilots, who
dubbed it a menace.  However, controllability was improved somewhat by
replacing  the  P-12-like corrugated metal vertical tail with a larger
design.  However, this  was  not  sufficient  to  overcome  the  basic
shortcoming  of  the  design, and the Army chose not to order the XP-9
into production.  The Army was in fact so dissatisfied with  the  XP-9
that they did not even exercise their option for five Y1P-9 monoplanes
to be built under the  P-12D  contract.   In  August  1931,  the  Army
relegated  the  XP-9  to  use  as a non-flying instructional airframe.
Only 15 flying hours had been completed.

Performance included a maximum speed of 213 mph and an  initial  climb
rate of 2560 ft/min.  An altitude of 5000 feet could be reached in 2.3
minutes, and service ceiling was 26,800 feet.  Range  was  425  miles.
Weights were 2669 lbs. empty, 3623 lb gross.

Sources:

  Boeing Aircraft since 1916, Peter M. Bowers, Naval Institute  Press,
  1989.

  The American Fighter, Enzo Angellucci and Peter Bowers, Orion Books,
  1987.

Joe Baugher       AT&T Bell Laboratories    2000 North Naperville Road 
		  Naperville, Illinois 60566-7033.   (708) 713-4548


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