The Lockheed Ventura was the result of a September 1939 proposal by Lockheed to the British Air Ministry for a military version of the Model 18 Lodestar twin-engined 15/18-passenger commercial transport. It was viewed as a successor to the Lockheed Hudson in RAF service. The Hudson was itself a military version of an earlier model of the Super Electra 10/14-passenger commercial transport.

Under the temporary design designation of L-108, the Lockheed Company considered several different proposals for a military version of the Model 18. The final plans was designated as the Model 37-21-01 which was powered by a pair of 1850 hp Pratt & Whitney S1A4-G Double Wasp eighteen-cylinder air-cooled radials. This engine was a commercial version of the military R-2800. The RAF was pleased with this proposal and ordered 300 examples in May of 1940 under the name "Ventura". Later in 1940, 375 more Venturas were ordered.

Since Lockheed now had sizable orders in hand from both domestic and overseas customers, they decided to have the Model 37 built by the Vega Airplane Company. The Vega Airplane Company was located right next door to Lockheed at Burbank, California. It had been founded in 1937 and had become a subsidiary of Lockheed. In recognition of the need for expanded output caused by the outbreak of war in Europe, Vega built a new plant at the Union Air Terminal at Burbank about a mile from the parent Lockheed plant. On December 31, 1941, the Vega Airplane Company formally merged with Lockheed. On November 30, 1943, the name Vega finally disappeared when the Vega Airplane Company was formally absorbed into Lockheed, its facilities becoming Lockheed's Plant A-1.

The Venture I had twin 1850 hp Pratt & Whitney S1A4-G Double Wasps air-cooled radial engines. It had a Maximum speed of 312 mph at 15,500 feet with a Cruising speed of 272 mph. Initial climb rate was 2035 feet per minute with a service ceiling of 25,000 feet. Normal range was 925 miles. The wingspan was 65 feet 6 inches, with a length of 51 feet 5 inches and the height was 11 feet 10 1/2 inches. It weighed 17,233 pounds empty, 22,500 pounds loaded and 26,000 pounds for maximum take-off. Its armament consisted of four 0.303-inch machine guns installed in dorsal turret, twin flexible 0.303-inch machine guns were mounted in the extreme nose and a pair of flexible 0.303-inch machine guns were mounted in a ventral position behind the wing trailing edge. Two fixed forward-firing 0.50-inch machine guns were installed in the upper decking of the nose. A bomb load of 2500 pounds could be carried in an internal bomb bay.

The first Ventura took off on its maiden flight at the Lockheed Air Terminal on July 31, 1941 and deliveries of Venturas to Britain began in September of 1941. 21 of the early production run of Ventura Is were retained in Canada for the RCAF. At least six were transferred to the South African Air Force.

The Ventura II was generally similar to the Ventura I, but was powered by 2000 hp Pratt & Whitney R-2800-31s instead of the Double Wasp S1A4-Gs of the Mark I version. It had a redesigned bomb bay capable of carrying 3000 pounds of bombs or 780-gallon ferry tanks. Production totaled 487 aircraft. Only 196 Ventura IIs actually reached Commonwealth forces, with 264 being retained by the USAAF as Model 37s. For some reason, they never got USAAF designations or serial numbers. The Ventura I was first delivered to the RAF in September of 1941 and went into service with No 21 Squadron at Bodney, Norfolk, in May of 1942. It also served with Nos 464 (RAAF) and 487 (RNZAF) Squadrons. It flew its first combat mission on November 3, 1942, an attack by three aircraft of No. 21 Squadron against a factory at Hengelo which had to be diverted into a raid against railway lines instead.

47 Venturas from Nos 21, 464 and 487 Squadrons took part along with Mosquitos and Bostons in a daylight low-level attack on December 6, 1942 against the Philips radio and vacuum tube factory at Eindhoven in the Netherlands. The raid did not go well--nine of the Venturas were shot down and 37 were damaged.

After this disaster, the Venturas switched to medium-altitude missions and attacked numerous targets in occupied Europe. On April 4, a formation of 24 Venturas were sent to bomb the Caen/Carpiquet airfield whereas another 24 Venturas were sent to attack the shipyards at Rotterdam. Two Venturas attacking Rotterdam were shot down by German fighters and three more were shot down by fighters on the Brest raid. On April 21, when Venturas of No 21 Squadron hit the marshaling yards at Abbeville, three more were shot down by fighters. On May 3, 1943, eleven Venturas from No 487 Squadron attacked a power station in Amsterdam, but only one Ventura survived determined attacks from German fighters. The formation leader, Sqdn Ldr Leonard H. Trent, managed to shoot down a Bf 109 with his forward-firing guns before being shot down himself. Sqdn Ldr Trent was captured and spent the rest of the war in a POW camp. He managed to survive the war and was later awarded the Victoria Cross for his bravery.

On May 24, No. 487 Squadron resumed operations. An attack on a power station and coking plant at Zeebrugge came off without losses. On May 29, No. 21 Squadron attacked Zeebrugge again. Two Venturas got involved in a midair collision. One made it back safely, but the other was lost.

The Ventura was never very popular with its RAF crews. It was 50 mph faster than the Hudson which preceded it and had a bombload of 2500 pounds instead of the former's 1000 pounds, but it was over 7500 pounds heavier. Losses were high and the aircraft was not really suitable as a bomber. The RAF Ventura I and II bombers were replaced by deHavilland Mosquitos by the summer of 1943. The last Ventura sortie took place with No. 21 Squadron on September 9, 1943.

21 Ventura Mk. Is and 108 Mk. II/IIAs were diverted to the Royal Canadian Air Force (RCAF) from British contracts. The first Ventura I was received in June of 1942. The Ventura I and II aircraft retained in Canada were used exclusively in training roles and never saw combat. They retained their RAF serial numbers and were assigned to No 340 Operational Training Unit at Pennfield Ridge, New Brunswick and No 1 Central Flying School at Trenton, Ontario.

The South African Air Force received 135 Ventura Mk I and II aircraft. They equipped three Squadrons (Nos 17, 22 and 27) which initially operated at home to protect shipping routes around the Cape. They also served in the Mediterranean. Venturas of No. 17 Squadron carried out anti-shipping strikes off the coast of Italy and No 452 flew a few night intruder missions. No 27 Squadron took over 500 Squadron's surviving Venturas and later operated from Malta. Venturas were operated by No. 27 Squadron until January of 1945, while other wartime Venturas, particularly in No. 299 Squadron of the RAF, were used as transports.

Michael Russell Your Independent guide to Aviation Article Source: http://EzineArticles.com/?expert=Michael_Russell