Wright Aeronautical Corporation GR-1820-G102A Cyclone

Squadron Leader James Addams, RAF, at left, and Kelly Johnson with the Lockheed B14L, N7205, Union Air Terminal, Burbank, California, December 1938. (Unattributed)

10 December 1938: At the Union Air Terminal, Burbank, California, Squadron Leader James Addams and Squadron Leader Randle, both Royal Air Force officers, took the prototype Lockheed B14L for its first flight.

The prototype Lockheed B-14L (Hudson Mk.I, N7205) photographed during its first flight, 10 December 1938. Note the mockup dorsal gun turret and painted-out British insignia. (W.J. “Billy” Gray)

The B14L (also identified as Model 214-40-01) was a twin engine light bomber developed by the Lockheed Aircraft Company from its Model 14 Super Electra civil transport. Both types were designed by the legendary Clarence L. (“Kelly”) Johnson. The prototype was purchased by Great Britain and designated Hudson Mk.I. It was assigned the R.A.F. identification N7205.

(Los Angeles Times, Vol. LVIII, Thursday Morning, 22 December 1938, Page 9, Columns 2–4)

Squadron Leader James Addams, RAF, and Clarence L. (“Kelly”) Johnson shake hands in front of the prototype Lockheed B14L (Hudson Mk.I N7205) at Union Air Terminal, Burbank, California, December 1938. (The Honolulu Advertiser, Vol. 83, No. 18,694, Saturday, 31 December 1938, Page 2, Columns 3–6_)

Lockheed Hudson Mk.I N7205 was partially disassembled and transported to England aboard a ship. (Royal Air Force)

Lockheed Hudson Mk.I N7205 at RAF Northolt, South Ruislip, near London, England,1939. (RAF Museum PC98/173/5840/14)

Gunnery tests of the prototype were carried out near Daggett, in the Mojave Desert of southern California, 100 statute miles (161 kilometers) northeast of Burbank.

The Lockheed Hudson was a twin-engine, mid-wing light bomber with conventional retractable landing gear. It was operated by a pilot, navigator/bombardier, radio operator/gunner, and a gunner in a dorsal power-operated turret. The Mk.I was 44 feet 3-7/8 inches (13.510 meters) long, with a wingspan of 65 feet, 6 inches (19.964 meters), and height of 11 feet, 10 inches (3.607 meters). It had an empty weight of 11,630 pounds (5,275 kilograms), and maximum gross weight of 17,500 pounds (7,938 kilograms).

Hudson Mark III, V8977: cabin interior with pilot’s position on the left. Photograph taken at Eastleigh, Hampshire. Photographed 24 July 1942. (Imperial War Museum, Royal Air Force Aircraft 1941–1959: ATP Collection (GSA 325). © IWM ATP 10925F )

The Hudson Mk.I was powered by two air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.875 liter) Wright Aeronautical Division Cyclone 9 GR-1820-G102A radial engines with a compression ratio of 6.3:1. They had a normal power rating of 900 horsepower at 2,200 r.p.m., at Sea Level, and 1,100 horsepower at 2,200 r.p.m. for takeoff. The engines drove three-blade adjustable pitch propellers through a 0.6875 gear reduction. The GR-1820-G102A was 4 feet, 0.12 inch (1.222 meters) long, 4 feet, 7.10 inches (1.400 meters) in diameter, and weighed 1,275 pounds (578 kilograms).

The Hudson Mk.I had a cruise speed of 220 miles per hour (354 km/h), and maximum speed of 246 miles per hour (396 km/h) at 6,500 feet (1,981 meters). Its service ceiling was 25,000 feet (7,620 meters), and its range, 1,960 miles (3,153 kilometers).

The Hudson was armed with two fixed, forward-firing .303-caliber (7.7 × 56mmR) Browning Mk.II machine guns located above the bombardier’s compartment, two .303 Mk.II guns in a power-operated Boulton Paul Aircraft Ltd. dorsal turret and a fifth flexible mount .303 machine gun was located in a ventral position. Each of these guns were capable of firing at a rate of 1,150 rounds per minute.

The bomber could carry four 250 pound (113 kilogram) bombs, or ten 100 pound (45 kilogram) bombs in an internal bomb bay.

“Armourers secure 250-lb GP bombs in the bomb bay of a Lockheed Hudson of No. 224 Sqyadron RAF at RAF Leuchars, Fife, Scotland.” (Flight Lieutenant Stanley Devon, RAF/Imperial War Museums CH 979)

British purchasing Commission contracted for 250 Hudson Mk.I bombers, 23 June 1938. Deliveries began in February 1939, with the 250th Hudson Mk.I delivered in October 1939.

Lockheed built 2,941 Hudson bombers in a number of configurations. 351 of these were Hudson Mk.Is.