Subject: Number Fifty-One in the Series--North American P-51 Mustang

From: [email-masked]
Date: 22 Feb 93 17:20:42 GMT

>From [email-masked]

The ultimate version of the Mustang was the P-51H, which was the 
fastest Mustang variant to see service and one of the fastest (if not 
the fastest) piston-engined fighters to enter production during the 
Second World War.  

The P-51H was an outgrowth of the experimental XP-51F and G 
lightweight Mustang projects of early 1944.  Rather than commit the F 
or G versions to production, the USAAF decided instead to produce a 
version powered by the uprated Packard Merlin V-1659-9 engine.  This 
engine had the Simmons automatic boost control for constant manifold 
pressure maintenance and was equipped with a water injection system 
which made it possible to overboost the engine to achieve war 
emergency powers in excess of 2000 hp for brief periods.  North 
American Aviation gave the project the company designation NA 126, and 
it was ordered into production as the P-51H in June of 1944 even 
before much of the initial design work was done.  

The weight-savings program which produced the XP-51F and XP-51G was 
put to good use in the design of the P-51H.  The fin and rudder were 
significantly increased in height and the rear fuselage was lengthened 
to 33 feet 4 inches (nearly two feet longer than the P-51D).  Other 
features were taken directly from the XP-51F project--it had the same 
shallower carburetor air intake and modified cowling with integral 
engine mounting, the same simplified undercarriage with smaller wheels 
and disc brakes, and it had the same broad-chord wing (without the 
leading edge "kink").  However, the cockpit canopy was much smaller 
than that of the XP-51F, being more nearly equal in size to that of 
the P-51D.  However, the profile of the canopy was quite different 
from that of the P-51D, with the top of the hump being much closer to 
the front just above the pilot's head.  The fuselage was modified in 
order to raise the cockpit to give an 8-degree gunsight deflection 
angle looking down along the top line from gunsight to spinner.  
Armament returned to six machine guns with 1880 total rounds, although 
alternative installations of four guns with 1600 total rounds could be 
fitted.  Provisions were made for normal loads of external stores.  
Access for gun servicing was improved by redesign of the wing doors 
and ammunition feed system, and by making the ammunition boxes 
removable.  The fuselage fuel tank was restored, but its capacity was 
fixed at 50 US gallons, giving a total internal fuel capacity of 255 
US gallons.  

The first P-51H-1-NA was flown by Bob Chilton on February 3, 1945.  
There were 20 P-51H-1-NAs built, all with the XP-51F tail.  The 
distinctive taller tail was installed on the P-51H-5-NA and later 
production block aircraft and was later retrofitted to earlier 
P-51H-1-NAs.  

Along with the Republic P-47N Thunderbolt, the P-51H was intended to 
be the leading USAAF fighter used during the upcoming invasion of 
Japan.  2000 P-51Hs were ordered, made up of 555 NA-126s and 1445 
NA-129s with minor differences.  All of these planes were to be built 
at the Inglewood factory.  1629 more examples were ordered from NAAs 
Dallas plant, these being designated P-51M.  The P-51M differed 
primarily in having the V-1650-9A engine, which had a lower war 
emergency rating by virtue of having the water injection deleted.  

One P-51H was given to the RAF for evaluation at Boscombe Down.  Its 
serial was KN987.  

The P-51H was too late to see action in the war in Europe.  By the 
late summer of 1945, some P-51Hs had been issued to a few operational 
units.  These units were in the process of working up to operational 
status when the war in the Pacific ended with the Japanese surrender.  
None had the opportunity to see any combat.  At the time of V-J Day, 
555 P-51Hs had rolled off the Inglewood production lines.  With the 
coming of peace, orders for 1445 more P-51Hs were cancelled, along 
with the entirety of the order for the Dallas-built P-51Ms after only 
one example had been completed.  

Also cancelled was an order for 1700 P-51Ls.  They were to have been 
similar to the P-51H but were to be equipped with the more powerful 
V-1650-11 engine with a Stromberg speed/density injection-type 
carburetor, rated at a peak power of 2270 hp with water injection.  
None were built.  

The last P-51H rolled off the production line in 1946.  

Specs of the P-51H-5-NA: 

One Packard Merlin V-1650-9 twelve-cylinder Vee liquid cooled engine 
rated at a war emergency power of 2218 hp at 10,200 feet with water 
injection.  Maximum speed was 444 mph at 5000 feet, 463 mph at 15,000 
feet, and 487 mph at 25,000 feet.  Range in clean condition was 755 
miles at 359 mph at 10,000 feet, 1975 miles at 239 mph at 10,000 feet.  
Range with two 62.5 Imp. gall. drop tanks was 1150 miles at 339 mph 
at 10,000 feet and 1530 miles at 243 mph at 10,000 feet.  An altitude 
of 5000 feet could be reached in 1.5 minutes, 15,000 feet in 5 
minutes.  Service ceiling was 41,600 feet.  Weights were 6585 pounds 
empty, 9500 pounds normal loaded, and 11,500 pounds maximum.  Wing 
span was 37 feet 0 inches, length was 33 feet 4 inches, height was 8 
feet 10 inches, and wing area was 235 square feet.  

Serials of the P-51H and P-51M: 

44-64160/64179 	North American P-51H-1-NA Mustang 
44-64180/64459 	North American P-51H-5-NA Mustang
44-64460/64714 North American P-51H-10-NA Mustang
45-11743 North American P-51M Mustang 

Sources:

  American Combat Planes, Ray Wagner, Third Enlarged Edition, Doubleday, 
  1982.  

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

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

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

  Fighting Mustang: The Chronicle of the P-51, William N. Hess, 
  Doubleday, 1970.  

  Classic Warplanes: North American P-51 Mustang, Bill Gunston, Gallery 
  Books, 1990.  

  Famous Fighters of the Second World War, Volume I, William Green, 
  1967.  

  British Military Aircraft Serials, 1912-1969, Bruce Robertson, Ian 
  Allen, 1969.  

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