Note: This suggestion was imported from the old War Thunder forum.
The Martin JRM Mars is perhaps one of the more recognizable large flying boat from the World War II era. However, the Mars was named after the Greco-Roman god of war for a reason, despite being later used as a heavy transport aircraft. This is because the Mars was originally designed as a maritime patrol bomber.
Today, I would like to suggest the XPB2M-1 Mars, a slightly smaller, yet still huge bomber version of the JRM Mars into the game.
The XPB2M-1 Mars mooring somewhere in 1942
The story of the bomber variant of the Mars started on 23 August 1938. The Glenn L. Martin Company received the contract from the US Navy for a new maritime patrol bomber flying boat to replace the PBY Catalina. The Martin company responded by delivering the PBM Mariner in September 1940. In the month before the Mariner’s delivery, however Martin has started the development of a scaled-up version of the Martin for future contract. And thus construction of the XPB2M “Mars” has begun.
The XPB2M (above) compared to the JRM (below). The JRM has a longer and more aerodynamically efficent nose, has single large tail fin instead of angled dual tails, has slightly wider rear fuselage to aid handling on the water, has steeper draught to accomodate more cargo, has more powerful variant of Wright R-3350 engines, and its defensive turrets were removed.
The XPB2M was revealed to the US Navy on 8 November 1941. Due to its immense estimated range of ~7,000 meters and large payload, the US Navy instantly ordered to prototype of the Mars. This is expected by Martin, as they have already built a facility for the mass production of the Mars two months earlier in 27 September of the same year.
The XPB2M Mars prototype under construction at Baltimore. Note the two A-26 Marauders in the bacground for the size of the aircraft.
The Mars was initially planned to be equipped with four Wright R-3350-4 Duplex Cyclone engine with 2,000 horsepower output. But Martin decided to change the engines to the more powerful Wright R-3350-18 with 2,500 horsepower as well as to change the wooden propeller to the metal equivalent. However, an engine fire during the new engine test caused the plane’s first flight to be delayed by 6 months to 23 June 1942. During the construction, the prototype was affectionally named “The Old Lady” for its impressive size.
Technical drawing and illustration of the XPB2M Mars with its intended defensive armaments.
Due to the Mars’ immense payload of 4.5 tons and a takeoff weight of 65 tons, the Mars is, unsurprisingly, a slow aircraft. At around 365 km/h top speed at sea level. Despite its size, the Mars is lightly armed. The Mars was to be equipped with eight 7.62 mm Browning machine guns in three powered dual mounts at its nose, dorsal, and tail. The other two were mounted in a single manual turret at its waist. The Mars can be loaded with up to 4,536 kg of bombs dropped from its internal wing bombing bay, as well as capable of carrying torpedoes.
Another image that illustrate the size of “The Old Lady”. Two Piper J3C-65 Cub was mounted on the Mars’ wings.
The XPB2M-1 Mars’ first flight begun on 23 June 1942 (though some source also stated 3 July 1942). The prototype was equipped only with two turrets at the nose and the tail. While the Mars is relatively slow, the plane is fairly manoverable for its size. The US Navy was satisfied with the Mars’ performance. However, by the time that the testing program has completed, the US Navy has already filled the gap of a large maritime patrol bomber flying boat with the PB2Y Coronado, and thus rendered the Mars somewhat obsolete. To not wasting the effort and an already built production hull of the Mars, however. The US Navy ordered the change in specification of the Mars into a heavy transport flying boat with the designation JRM and ordered 20 of the JRM, but later cut it down to 6, with 5 of the new JRM Mars delivered in 1947.
“The Old Lady”, now converted into a transport aircraft, flown over the Golden Gate bridge in 1944.
Meanwhile, the US Navy purchased the XPB2M-1 prototype from Martin and converted it into a cargo plane. Given new designation XPB2M-1R, “The Old Lady” has been deployed to carry a huge 5 tons of cargo from the mainland US to Hawaii and various Pacific islands during 1944 and early 1945 before withdrawn from service in March 1945. “The Old Lady” were later used as a training aircraft for the crew of the JRM before being scrapped in 1949.
The XPB2M-1 Mars is similar to another failed “super heavy” bomber of the USAAF, the Douglas XB-19. Due to the fact that both had a similar goal as a large bombers with extremely long range that were unachiveable during their intial plannings, but were plagued with its slow speed and problem with its engines that made both of them come out a little too late to have any use in the war. However, the Mras is more fortunate than the XP-19 due to the fact that it did saw services during the war as a cargo planes, and paved the way for the more capable strategic airlifters to take is place.
In War Thunder, the XPB2M-1 Mars will be something in-between the even more gigantic BV 238 and the slow yet heavily-loaded F.222.2 bombers. The Mars’ sheer size, poor top speed, and its dispropotionally small amount of defensive armaments will attract a lot of fighters. However, the Mars will be able to soak in a lot of damage and delivering huge payloads in return. Since we cannot have the more famous transport version of the Mars, I think the bomber version can be added to represent its importance as one of the first strategic airlifters.
Crew: 11; 2 pilots, 5 gunners, a bombardier, and 3 relief crews
Length: 117 ft 3 in (35.74 m)
Wingspan: 200 ft 0 in (60.96 m)
Height: 38 ft 5 in (11.71 m)
Wing area: 3,686 sq ft (342.4 m2)
Empty weight: 75,506 lb (34,249 kg)
Max. takeoff weight: 143,994 lb (65,315 kg)
Powerplant: 4 × Wright R-3350-18 Duplex Cyclone 18-cylinder radial engines, 2,500 hp each
Maximum speed: 192 knots (221 mph, 356 km/h)
Cruise speed: 165 knots (190 mph, 305 km/h)
Range: 4,300 nautical miles (5,000 mi, 8,000 km)
Service ceiling: 14,600 ft (4,450 m)
Climb rate: 27.1 minutes to climb to 10,000 feet (3,048 meters)
Defensive: 8 × .30 cal (7.62 mm) Browning light machine guns. Six in a powered twin turret at the nose, dorsal, and tail, other two in a single manual turret at the waist.
Suspended: Up to 10,000 lbs (~4,534 kg) of bombs inside the bomb wing bomb bays, with additional torpedo armaments.
Martin PB2M Mars (in Russian)
https://books.google.co.th/books?id=2ykDAAAAMBAJ&pg=PA82&dq=popular+science+may+1941&hl=en&ei=-5-VTLmSJMqmnQeu-5SxBw&sa=X&oi=book_result&ct=result&redir_esc=y#v=onepage&q=popular science may 1941&f=true
Bridgman, Leonard. “The Martin Model 170 Mars.” Jane’s Fighting Aircraft of World War II. London: Studio, 1946. ISBN 1-85170-493-0
Coulson, Wayne and Steve Ginter. The Mighty Martin Mars: From 1945 US Navy Transport to 21st Century, Initial Attack Firefighting. Port Alberni, British Columbia, Canada: Half Moon Bay Publications, 2009. ISBN 978-0-9812987-0-2
Ginter, Steve. Martin Mars XPB2M-1R & JRM Flying Boats (Naval Fighters 29). Simi Valley, California, USA: Ginter Books, 1995. ISBN 0-942612-29-9