Subject: Number Thirty-Nine in the Series--Bell P-39 Airacobra (7 of 9)

From: [email-masked] (Joseph F Baugher)
Date: 18 Dec 92 21:25:50 GMT

>From Joseph F Baugher <[email-masked]>

The P-39Q was the last version of the Airacobra to roll off the 
production lines at Bell.  It was also the version which was built in 
the largest numbers, 4905 P-39Qs being built before production finally 
ended.  

The principal difference between the P-39Q and earlier version was in 
the fighter's armament--the four wing-mounted 0.30-inch machine guns 
were replaced by a single 0.50-inch machine gun mounted in a fairing 
underneath each wing.  The ammunition capacity of the underwing guns 
was 300 rounds per gun.  The two fuselage-mounted 0.50-inch machine 
guns with 200 rpg, plus the hub-mounted 37-mm cannon with 30 rounds, 
were retained.  The replacement of the four wing guns was generally 
applauded by pilots, most of whom thought that the 0-30-inch guns of 
the earlier versions were too light to be effective and it wasn't 
worth the fuel to carry 4000 rounds of 0.30-inch ammunition.  The 
engine was the Allison V-1710-85 of 1200 hp, the same powerplant that 
was used in the P-39N.  

There were several production blocks of the P-39Q: 

P-39Q-1-BE: Retained the 72.4 Imp gallon fuel capacity of the P-39N-5 
but returned to the original 231 pounds of armor of the P-39N-1.  

P-39Q-5-BE: Reverted to the lighter armor fit of the P-39N-5 (193.4 
pounds).  as well as the use of the full wing fuel capacity (92.6 Imp 
gall) characteristic of the P-39M.  

P-39Q-10-BE: Internal fuel capacity rose to 100 Imp gallons and armor 
weight went to 227.1 pounds.  

P-39Q-15-BE: Differed from the Q-10 in minor equipment variations.  

P-39Q-20-BE: The underwing 0.50-inch machine gun pods were sometimes 
omitted in this version.  

P-39Q-21-BE: Four-bladed propeller was fitted.  

P-39Q-25-BE: Export variant of the Q-21.  Otherwise identical.  

P-39Q-30-BE: Tests indicated that directional stability was materially 
worsened by the four-bladed propeller, and this version reverted to 
the three-bladed unit.  This was the last production version of the 
P-39Q.  

A few P-39Qs were modified into two seaters with dual controls for use 
as advanced trainers under the designation RP-39Q (redesignated TP-39Q 
after 1944).  The second cockpit was sort of "grafted" in front of the 
original cockpit, and the pilot in this extra cockpit sat under a 
hinged canopy.  The tail fillet was enlarged and an an additional 
shallow ventral fin was fitted under the rear fuselage.  These 
modifications produced one of the most grotesque aircraft I have ever 
seen.  :-) 

Production of the P-39Q finally terminated in August of 1944.  Most of 
the P-39Qs were delivered to the Soviet Union.  Only a few ended up 
serving with American units.  One of these was the 332nd Fighter Group 
which took on 75 P-39Qs in Italy in February 1944.  After only two 
months, these Airacobras were replaced by P-47s, finally retiring the 
type from US service.  

Specs of the P-39Q-5-BE: 

One Allison V-1710-85 engine rated at 1200 hp at sea level and 1125 hp 
at 15,500 feet.  Maximum speed 330 mph at 5000 feet, 357 mph at 10,000 
feet, 376 mph at 15,000 feet.  Climb to 5000 feet in 2.0 minutes.  
Climb to 20,000 feet in 8.5 minutes.  Maximum range (clean) was 525 
miles at 20,000 feet at 250 mph.  With one 145.7 Imp gal drop tank, 
range was 1075 miles at 196 mph.  Service ceiling was 35,000 feet.  
Weights were 5645 pounds empty, 7600 pounds normal loaded, 8300 pounds 
maximum loaded.  Dimensions were wingspan 34 feet 0 inches, length 30 
feet 2 inches, height 12 feet 5 inches, wing area 213 square feet.  

A P-39Q (serial number uncertain--anyone know? I wrote down a tail 
number of 298667 when I was there, but this can't be correct) is on 
display at the WPAFB Museum.  It is, however, marked as a P-39J serial 
number 41-7073.  

P-39Q-15 Ser No 44-2433 "Galloping Gertie" is currently in storage at 
the Paul Garber Storage and Restoration Facility in Suitland, 
Maryland.  

Serials of the P-39Q: 

42-19446/19595 		Bell P-39Q-1 Airacobra 
42-19596/20545 		Bell P-39Q-5 Airacobra 
42-20546/21250 		Bell P-39Q-10 Airacobra 
44-2001/3000 		Bell P-39Q-15 Airacobra 
44-3001/3850 		Bell P-39Q-20 Airacobra 
44-3851/3858 		Bell P-39Q-21 Airacobra 
44-3859/3860 		Bell P-39Q-20 Airacobra 
44-3861/3864 		Bell P-39Q-21 Airacobra 
44-3865/3870 		Bell P-39Q-20 Airacobra 
44-3871/3874 		Bell P-39Q-21 Airacobra 
44-3875/3880 		Bell P-39Q-20 Airacobra 
44-3881/3884 		Bell P-39Q-21 Airacobra 
44-3885/3890 		Bell P-39Q-20 Airacobra 
44-3891/3894 		Bell P-39Q-21 Airacobra 
44-3895/3900 		Bell P-39Q-20 Airacobra 
44-3901/3904 		Bell P-39Q-21 Airacobra 
44-3905/3910 		Bell P-39Q-20 Airacobra 
44-3911/3914 		Bell P-39Q-21 Airacobra 
44-3915/3919 		Bell P-39Q-20 Airacobra 
44-3920/3936 		Bell P-39Q-21 Airacobra 
44-3937/3940 		Bell P-39Q-20 Airacobra 
44-3941/4000 		Bell P-39Q-21 Airacobra 
44/32167/32666 		Bell P-39Q-25 Airacobra 
44/70905/71104 		Bell P-39Q-25 Airacobra 
44/71105/71504 		Bell P-39Q-30 Airacobra 

Sources:

  War Planes of the Second World War, Fighters, Volume Four, William Green,
  Doubleday, 1964.

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

  United States Military Aircraft since 1909, Gordon Swanborough and Peter M.
  Bowers, Smithsonian Institution Press, 1989.

  P-39 Airacobra in Action, Ernie MCDowell, Squadron/Signal Publications, 1980

  The Calamitous 'Cobra, Air Enthusiast, August 1971.

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