Article 16490 of rec.aviation.military:
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From: jfb@usgp1.ih.att.com (Joe Baugher)
Subject: Bomber Series--Martin B-26 Marauder (1 of 18)
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Summary: B-26
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Date: Wed, 15 Mar 1995 02:03:51 GMT
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The Martin B-26 Marauder was one of the most controversial American 
combat aircraft of the Second World War.  It was primarily used in 
Europe, and was in fact numerically the most important USAAF medium 
bomber used in that theatre of action.  However, on four occasions, 
investigation boards had met to decide if the development and 
production of the Marauder should continue.  The Marauder survived all 
attempts to remove it from service, and by 1944, the B-26s of the US 
9th Air Force had the lowest loss rate on operational missions of any 
American aircraft in the European theatre, reaching a point less than 
one half of one percent.  

Despite its high landing speed of 130 mph, which remained essentially 
unchanged throughout the entire production career of the B-26 in spite 
of numerous modifications made to reduce it, the Marauder had no 
really vicious flying characteristics and its single-engine 
performance was actually fairly good.  Although at one time the B-26 
was considered so dangerous an aircraft that aircrews tried to avoid 
getting assigned to Marauder-equipped units and civilian ferry crews 
actually refused to fly B-26s, it turned out that the Marauder could 
be safely flown if crews were adequately trained and knew what they 
were doing.  It nevertheless did demand somewhat of a higher standard 
of training from its crews than did its stablemate, the B-25 Mitchell.  
However, once mastered, the B-26 offered a level of operational 
immunity to its crews unmatched by any other aircraft in its class.  

A total of 5157 B-26 Marauders were built.  Although on paper the B-26 
was a more advanced aircraft than its stablemate, the North American 
B-25 Mitchell, it was built in much fewer numbers because it was more 
expensive to manufacture and had a higher accident rate.  

One of the most commonly-asked questions is the difference between the 
Martin B-26 Marauder and the Douglas B-26 Invader.  They were two 
completely different aircraft and had been designed to completely 
different requirements.  The Douglas B-26 Invader had been originally 
been designated A-26, and was a twin-engined attack bomber intended as 
a successor to the Douglas A-20 Havoc.  In 1948, the newly-independent 
Air Force decided to eliminate the A-for-Attack series letter as a 
separate designation, and the A-26 Invader was redesignated B-26, in 
the bomber series.  There was no danger of confusion with the Martin 
B-26 Marauder, since this aircraft was by that time no longer in 
service with the US Air Force.  

The history of the Martin Marauder dates back to early 1939.  Both the 
North American B-25 Mitchell and the Martin B-26 Marauder owe their 
origin to the same Army Air Corps specification.  On March 11, 1939, 
the Air Corps issued Proposal No. 39-640 for the design of a new 
medium bomber.  According to the requirements listed in the 
specification, a bombload of 3000 pounds was to be carried over a 
range of 2000 miles at a top speed of over 300 mph and at a service 
ceiling exceeding 20,000 feet.  The crew was to be five and armament 
was to consist of four 0.30-inch machine guns.  The proposal called 
for either the Pratt & Whitney R-2800, the Wright R-2600, or the 
Wright R-3350 radial engine.  

Requests for proposals were widely circulated throughout the industry.  
Proposals were received from Martin, Douglas, Stearman, and North 
American.  The proposal of the Glenn L. Martin company of Middle 
River, Maryland (near Baltimore) was assigned the company designation 
of Model 179.  Martin assigned 26-year old aeronautical engineer 
Peyton M. Magruder as Project Engineer for the Model 179.  Magruder 
and his team chose a low-drag profile fuselage with a circular cross 
section.  Since the Army wanted a high maximum speed but hadn't 
specified any limitation on landing speed, the team selected a 
high-mounted wing with a wingspan of only 65 feet.  Its small area 
gave a wing loading of more than 50 pounds per square foot.  The wing 
was shoulder-mounted to leave the central fuselage free for bomb 
stowage.  The wings were unusual in possessing no fillets.  The 
engines were to be a pair of 1850 hp Pratt & Whitney R-2800-5 Double 
Wasp air-cooled radials, which were the most powerful engines 
available at the time.  Two-speed mechanical superchargers were 
installed in order to maintain engine power up to medium altitudes, 
and ejector exhausts vented on each side of the closely-cowled 
nacelles.  The engines drove four-bladed 13 foot 6 inch Curtiss 
Electric propellers.  Large spinners were fitted to the propellers, 
and root cuffs were added to aid in engine cooling.  

The armament included a flexible 0.30-inch machine gun installed in 
the tip of a transparent nose cone and operated by the bombardier.  
Two 0.50-inch machine guns were installed in a Martin-designed dorsal 
turret located behind the bomb bay just ahead of the tail.  This was 
the first power-operated turret to be fitted to an American bomber.  
Another 0.30-inch flexible machine gun was installed in a 
manually-operated tunnel position cut into the lower rear fuselage.  
There was a 0.50-inch manually-operated machine gun installed in a 
pointed tailcone.  The tail gunner had enough room to sit in an 
upright position, unlike the prone position that had been provided
in the early B-25.  

There were two bomb bays, fore and aft.  The bomb bay doors were 
unusual in being split in tandem, the forward pair folding in half 
when opened and the aft set being hinged normally to open outward.  
Two 2000-lb bombs could be carried in the main bomb bay, but up to 
4800 pounds of smaller bombs could be carried if the aft bay was used 
as well.  

Detailed design of the Model 179 was completed by June of 1939.  On 
July 5, 1939, the Model 179 was submitted to a Wright Field Board.  
The Martin design was rated the highest of those submitted, and on 
August 10, 1939, the Army issued a contract for 201 Model 179s under 
the designation B-26.  This contract was finally approved on September 
10.  At the same time, the competing North American NA-62 was issued a 
contract for 184 examples under the designation B-25.  Since the 
design had been ordered "off the drawing board", there was no XB-26 as 
such.  

Although the first B-26 had yet to fly, orders for 139 B-26As with 
self-sealing tanks and armor were issued on September 16.  Further 
orders for 719 B-26Bs on September 28, 1940 brought the total B-26 
order to 1131 aircraft.  

Early wind tunnel test models of the B-26 had featured a twin tail, 
which designers thought would provide better aerodynamic control.  
This was dropped in favor of a single fin and rudder so that the tail 
gunner would have a better field of view.  

The B-26 had a semi-monocoque aluminum alloy fuselage fabricated in 
three sections.  The fuselage had four main longerons, transverse 
circular frames, and longitudinal stringers covered by a metal skin.  
The mid section with the bomb bays was built integrally with the wing 
section.  The retractable tricycle landing gear was hydraulically 
actuated.  The nosewheel pivoted 90 degrees to retract into the nose 
section, and the mainwheels folded backwards into the engine nacelles.  
The tail fins were of smooth stressed skin cantilever structure.  The 
elevators were covered with metal skin, but the rudder was fabric 
covered.  

The first B-26 (c/n 1226, USAAF serial 40-1361) took off on its maiden 
flight on November 25, 1940, with chief engineer and test pilot 
William K.  Ebel at the controls.  The first B-26 initially flew 
without any armament fitted.  

The first 113 hours of flight testing went fairly well, and there were 
few modifications needed.  However, a slight rudder overbalance 
required that the direction of travel of the trim tabs be reversed.  

Since there was no prototype, the first few production aircraft were 
used for test purposes.  On February 22, 1941, the first four B-26s 
were accepted by the USAAF.  The first to use the B-26 was the 22nd 
Bombardment Group (Medium) based at Langley Field, Virginia, which had 
previously operated Douglas B-18s.  

A series of failures of the front wheel strut resulted in a delay in 
bringing the B-26 to full operational status.  Although the forward 
landing gear strut was strengthened in an attempt to correct this 
problem, the true cause was an improper weight distribution.  The 
manufacturer had been forced to deliver the first few B-26s without 
guns, and had trimmed them for delivery flights by carefully loading 
service tools and spare parts as ballast.  When the Army took the 
planes over, they removed the ballast without replacement and the 
resultant forward movement of the center of gravity had multiplied the 
loads on the nosewheel, causing the accidents.  The installations of 
the guns corrected the problem.  

The last B-26 was delivered in October of 1941.  That month, the 
Martin Middle River production line shifted over to the B-26A version.  

Serials of Martin B-26 Marauder:

40-1361/1561		Martin B-26 Marauder
				1464 acquired by David Tallichet for
				restoration.


Specification of Martin B-26 Marauder:  

Two Pratt & Whitney R-2800-5 Double Wasp air cooled radial engines, 
rated at 1850 hp each.  
Performance:  Maximum speed 315 mph at 15,000 feet.  Cruising speed 
265 mph.  An altitude of 15,000 feet could be attained in 12.5 
minutes.  Service ceiling 25,000 feet.  Range was 1000 miles at 265 
mph with a 3000-pound bombload.  
Weights:  21,375 pounds empty, 32,025 pounds gross.  
Dimensions:  Wingspan 65 feet 0 inches, length 56 feet 0 inches, 
height 19 feet 10 inches, wing area 602 square feet.  
Armament:  One flexible 0.30-inch machine gun installed in the tip of 
a transparent nose cone and operated by the bombardier.  Two 0.50-inch 
machine guns in a Martin-designed dorsal turret located behind the 
bomb bay just ahead of the tail.  One 0.30-inch flexible machine gun 
was installed in a tunnel position in the lower rear fuselage.  One 
flexible 0.50-inch machine installed in a tail position.  The maximum 
bombload was 5800 pounds.  

Sources:

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

   The Martin B-26 Marauder, J. K. Havener, TAB Aero, 1988.

   Me & My Gal--The Stormy Combat Romance Between a WW II Bomber
   Pilot and His Martin B-26, Charles O'Mahony, Wings, 
   December 1994.

   The Martin B-26B and C Marauder, Ray Wagner, Aircraft in
   Profile, Doubleday, 1965.

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

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

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