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Martin Baltimore Light / Medium Bomber (1941)

Authored By Staff Writer | Last Updated: 1/8/2015

Though produced in limited numbers and neglected by the USAAF, the Baltimore found life with the British Royal Air Force and others during World War 2.

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The Martin Baltimore (Model 187) was a light-/medium-class bomber whose design developed from the Martin Maryland series aircraft. Despite it being an American design, the twin-engine, four-crew platform was never fielded by the United States war machine n World War 2. Its primary operator became the United Kingdom largely by way of Lend-Lease which allowed America to supply war goods to her Allies without formally entering the war. The Baltimore would see operational service fin the conflict from 1942 into the middle of 1945, covering various battlescapes such as North Africa, the Middle East and the European Theater. By the end of the war, nearly 1,600 examples would be in circulation under no fewer than six major production marks.

The Baltimore was developed under the A-23 designation following its origination from the preceding A-22, which served as the Martin Maryland (detailed elsewhere on this site). The A-23 was given a revised, deeper fuselage design for more internal volume as well as uprated engines to help improve performance and first flew on June 14th, 1941. While the initial customer for the A-23 was the French (the USAAC passed on the design), the Fall of France in May of 1940 precluded its deliveries and a resources-strapped Britain accepted the order. As such, the name of Baltimore was bestowed on the line and the name stuck with the design for the entirety of its service career. A-23s arrived in the latter portion of 1941 and were baptized in combat over the skies of the Middle East.

Initial models were the Baltimore Mk I which fitted 2 x Wright GR-2600-A5B radial piston engines of 1,600 horsepower each. These aircraft featured a defensive armament arrangement of some 10 x 7.7mm machine guns though only two were set in trainable mountings at dorsal and ventral gun positions (the remaining stock were in fixed mountings on the wings and fuselage including a pair of aft-firing guns). 50 of the type were eventually produced.

This mark was then followed by the Mk II which added two more 7.7mm machine guns, one to the trainable dorsal and ventral positions. 100 of the variant were produced.

The Mark III arrived by mid-1942 and featured a power-assisted Boulton-Paul dorsal turret which could be arranged with either quad (4) or dual (2) 7.7mm machine guns. The Mk III was also fitted with 2 x Wright GR-2600-19 "Cyclone" radial piston engines capable of 1,660 horsepower each providing the Baltimore with a maximum speed of over 300 miles per hour. Fuselage design made the Baltimore Mk appear very tall and narrow which restricted internal operating spaces for the four crewmembers (pilot, navigator/bombardier, radio operator and dedicated gunner). The nose assembly was consistent with other America-designed bombers of the time and featured a heavily glazed cone leading up to the stepped cockpit. Wings were mid-mounted on the fuselage with a dorsal turret seated along the fuselage spine, facing rear, and ahead of the single vertical tail fin. Bomb bay doors made up nearly the entire length of the fuselage underside. The Mk III was produced across 250 examples in all.


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Specifications for the
Martin Baltimore
Light / Medium Bomber


Focus Model: Martin Baltimore Mk III
Country of Origin: United States
Manufacturer: Glenn L. Martin Company - USA
Initial Year of Service: 1941
Production: 1,575


Crew: 4


Length: 48.46 ft (14.77 m)
Width: 61.32 ft (18.69 m)
Height: 17.75ft (5.41 m)
Weight (Empty): 15,201 lb (6,895 kg)
Weight (MTOW): 23,001 lb (10,433 kg)


Powerplant: 2 x Wright GR-2600-19 Cyclone radial piston engines generating 1,660 horsepower each.


Maximum Speed: 302 mph (486 kmh; 262 kts)
Maximum Range: 951 miles (1,530 km)
Service Ceiling: 23,999 ft (7,315 m; 4.5 miles)
Rate-of-Climb: 1,250 feet-per-minute (381 m/min)


Hardpoints: 0
Armament Suite:
STANDARD:
4 x 7.7mm Browning Machine Guns in wings
2 OR 4 x 7.7mm Browning Machine Guns in dorsal turret.
2 x 7.7mm Browning Machine Guns in ventral gun position.

OPTIONAL:
Maximum ordnance loadout of up to 2,000lbs.


Variants:
Model 187 - Modified Light Bomber platform based on the Martin Maryland design.


Mk I - RAF use; initial production mark; sans power-operated dorsal turret; single 7.7mm machine gun in dorsal mount.

Mk II - RAF use; early production examples sans power-operated Boulton-Paul dorsal turret.

Mk III - RAF use; fitted with power-operated dorsal turret with 2 or 4 x 7.7mm machine guns.

Mk IIIA - RAF use based on the USAAF order of the A-30 Baltimore Light/Medium Bomber; fitted with Martin 250CE-brand turret fielding 2 x 12.7mm machine guns.

Mk IV - Based on the Mk IIIA model.

Mk V - Fitted with uprated Wright-brand GR-2600 powerplants; 12.7mm machine guns in wing mounts as opposed to 7.7mm caliber; appearing in 1944.

A-30 - USAAF Brand

A-30A - USAAF Brand

A-30A-10-MA - USAAF Brand

RA-30 - Reconnaissance Variant


Operators:
France (Free French); Italy (Co-Belligerent Forces); Turkey; United Kingdom; United States