Article 10408 of rec.aviation.military:
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From: jfb@usgp1.ih.att.com (Joe Baugher)
Subject: Bomber Series--North American B-25 Mitchell (7 of 32)
Message-ID: <D29qBM.DMD@ssbunews.ih.att.com>
Summary: B-25D 
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Date: Thu, 12 Jan 1995 01:18:58 GMT
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The B-25D was the version of the B-25C built by the North American 
factory at Kansas City, Kansas.  

In 1940, American military planners recognized that the war in Europe 
would create such an increased need for military aircraft that 
existing manufacturing facilities would be unable to keep up with the 
demand.  Consequently, the US government approved the construction of 
entirely new aircraft plants.  These new plants would be constructed 
mainly in the Midwest, well isolated, it was hoped, from the threat of 
bombing raids from either German or Japanese aircraft.  Ownership of 
these plants would be retained by the government, but they would be 
leased to private aircraft manufacturers for the purpose of fulfilling 
military contracts.  

One of these government-owned plant was in Kansas City, Kansas.  Its 
construction was authorized in December of 1940, and was leased by 
North American Aviation for the purpose of manufacturing B-25 Mitchell 
medium bombers.  The Fisher Body Division of the General Motors 
Corporation was named as a major subcontractor.  At first, plans were 
for Fisher to perform most of the manufacturing, with North 
American/Kansas doing most of the final assembly.  However, the 
program at the Kansas facility was later expanded to include 
manufacture as well, and at the period of peak production, Kansas City 
was performing 71 percent of the effort.  

An initial order for 1200 B-25D (NA-82) bombers was approved on June 
28, 1941.  North American Inglewood manufactured and supplied the 
parts for the first 100 B-25Ds built at Kansas City.  The first two 
B-25Ds were accepted in February of 1942.  Subsequent B-25Ds were 
built almost entirely by Fisher and by North American/Kansas.  
Beginning with B-25D serial number 41-29748, Fisher supplied outer 
wings, fuselage side panels, control surfaces, and transparent 
enclosures to Kansas City for mating with center sections and with 
other parts manufactured there.  

The B-25D was virtually identical to the B-25D, and many of the 
innovations introduced on the B-25D production line at Kansas City 
paralleled those introduced on the B-25C line at Inglewood.  
Generally, it was impossible to tell the difference between a B-25C 
and a B-25D without a knowledge of the serial numbers.  

Beginning with the B-25D-1 production block, external wing bomb racks 
were provided, additional self-sealing tanks were installed in the 
outer wing panels (adding 304 US gallons to the fuel capacity), 
carburetor air filters were installed, self-sealing oil tanks were 
provided, provisions were made for the installation of torpedo racks, 
a scanning blister was installed over the navigator's compartment, 
Bendix Amplidyne turrets were installed, and the flame-dampening 
"finger"-type engine exhausts were installed.  The external bomb racks 
could carry six to eight bombs in the 100-325 pound range.  

In the B-25D-5 production block, the 0.30-inch machine gun in the nose 
was replaced with a pair of fixed 0.50-inch and a single flexible 
0.50-inch machine guns.  This made them different from the B-25C's, 
which had only a single 0.50-inch fixed gun in the nose.  An improved 
scanning lens for the sighting system for the retractable ventral 
turret was provided, and provisions for a 585-gallon droppable 
bomb-bay fuel tank were installed on every third airplane through 
41-30532.  Provisions for additional cabin heating were added on 
B-25D-5 No.  41-30057 onward.  

On the B-25D-10 production block, additional provisions were made for 
better winterization, a remote reading compass was installed, 
emergency hydraulic landing gear lowering mechanisms were provided, 
and the conduit shielding box was eliminated.  

Effective on B-25D-15 and subsequent production blocks, the 
flame-dampening "finger"-type stack exhaust collector was replaced 
with individual Clayton "S"- shaped exhaust stacks connected to each 
cylinder, with individual cutouts and fairings being provided in the 
cowling where the stacks protruded.  

Beginning with B-25D-15 No. 41-30533, a clear vision windshield was 
installed.  A 230-US gallon self-sealing bomb bay fuel tank was 
installed, and a 325-gallon metal bomb bay fuel tank was installed on 
every other plane.  Additional armor plate was installed behind the 
copilot.  

On the B-25D-25 production block, a portable oxygen system was added.  

The last (B-25D-30) production block introduced more winterization 
changes, including a windshield defroster.  

The first B-25D was accepted by the USAAF in February 1942, with the 
last being accepted in March of 1944.  

Serials of B-25D Mitchell:

41-29648/29847		North American B-25D Mitchell
				c/n 87-7813/8012
41-29848/29947		North American B-25D-1 Mitchell
				c/n 87-8013/8112
41-29948/30172		North American B-25D-5 Mitchell
				c/n 87-8113/8337
41-30173/30352		North American B-25D-10 Mitchell
				c/n 87-8338/8517
41-30353/30532		North American B-25D-15 Mitchell
				c/n 87-8518/8698
41-30533/30847		North American B-25D-20 Mitchell
				c/n 87-8699/9012
42-87113/87137		North American B-25D-20 Mitchell
				c/n 100-20606/100-20630 
42-87138/87452		North American B-25D-25 Mitchell
				c/n 100-20631/100-20945 
42-87453/87612		North American B-25D-30 Mitchell
				c/n 100-20946/100-21105 
43-3280/3619		North American B-25D-30 Mitchell
				c/n 100-23606/100-23945  
43-3620/3869		North American B-25D-35 Mitchell
				c/n 100-23946/100-14195

Specification of the North American B-25D Mitchell:  

Two Wright R-2600-13 Double Cyclone fourteen-cylinder air-cooled 
radials, each rated at 1700 hp each for takeoff, 1500 hp at 2400 rpm.  
Equipped with Holley 1685HA carburetors.  
Performance:  Maximum speed 284 mph at 15,000 feet.  Cruising speed 
233 mph at 15,000 feet.  Initial climb rate 1100 feet per minute.  An 
altitude of 15,000 feet could be reached in 16.5 minutes.  Service 
ceiling 24,000 feet, Range 1500 miles with 3000 pounds of bombs.  
Weights:  20,300 pounds empty, 34,000 pounds maximum loaded.  
Dimensions:  wingspan 67 feet 67.7 inches, length 53 feet 0 inches, 
height 15 feet 9 inches, wing area 610 square feet.  
Fuel:  The fuel capacity consisted of four tanks in the inner wing 
panels, with a total capacity of 670 US gallons.  In addition, a 
515-gallon tank could be installed in the bomb bay for ferrying 
purposes, bringing total fuel capacity to 1255 US gallons.  Later 
versions had additional auxiliary fuel tanks in the outer wing panels.  
Later versions could also have 125-gallon tanks fitted in side waist 
positions, a 215-gallon self-sealing fuel tank installed in the bomb 
bay, and provisions could be made for a droppable 335-gallon metal 
bomb-bay fuel tank.  
Armament:  Two 0.50-inch machine guns in dorsal turret.  Two 0.50-inch 
machine guns in retractable ventral turret.  One 0.30-inch machine gun 
in flexible mount in the nose.  Starting with B-25D-5 the 0.30-inch 
nose gun was removed and replaced by a flexible 0.50-inch machine gun 
in the extreme nose and two fixed 0.50-inch machine mounted in the 
nose and firing through holes cut into the side of the Plexiglas 
glazing.  Normal bomb load was 3000 pounds but could be increased on 
the B-25D-1-NA with external underwing racks to a maximum of 5200 
pounds.  

Sources:

   B-25 Mitchell: The Magnificent Medium, N. L. Avery, Phalanx, 1992.

   Medium with the Mostest--The B-25 Mitchell, Jerry Scutts,
   Air International, Vol. 44, Nos 2 and 3, 1993.

   Boston, Mitchell, and Liberator in Australian Service, Stewart
   Wilson, Aerospace Publications, 1992.

   Famous Bombers of the Second World War, William Green, Doubleday,
   1959.

   North American's Flying Gun--The Story of the B-25 From Paper
   Airplane to Legendary Bomber, Jack Dean, Wings, Vol 23 No 4, 1993.

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

   North American B-25A-G Mitchell, Aircraft in Profile, Doubleday, 
   1966.

   Jane's American Fighting Aircraft of the 20th Century, Michael J.
   H. Taylor.


Joe Baugher			  **************************************
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