Lockheed 37 Ventura and Lockheed-Vega 15 Harpoon
The Ventura was developed by Lockheed as a bomber version of the Lodestar to fulfill a number of British Air Ministry requirements, including as a replacement for both the Lockheed Hudson and the Bristol Blenheim. An initial order for 25 was signed in February 1940, but had grown to 675 units by the end of the year. Production was entrusted to the Vega Airplane Company, co-located with Lockheed at Burbank, and by the time of the first flight, discussions were under way for a follow-on order for 750 as part of the lend-lease programme. Most of these lend-lease aircraft were in fact delivered to the United States Army Air Force as B-34 Lexingtons, serving in a variety of roles including bomber training, gunnery instruction and target towing.
In 1942, the United States Navy took over full responsibility for airborne anti-submarine warfare and in order to allow Lockheed-Vega to concentrate on developing the PV-2, the Air Force terminated production of the B-34. Some 1,500 Harpoons were ordered, but contracts were terminated on V-J Day by which time less than a third of that number had been built. Like the earlier Super Electra, the Ventura proved to be a popular choice as an executive transport after World War II, and several specialist conversions were carried out.
First flight: 31 Jul 41 (c/n 4001, AE658)
Production: 3,028, at Burbank, CA
First delivery: Sep 41, to the Royal Air Force
Last delivery: 27 Sep 45, to the US Navy (c/n 15-1605, Bu84061)
Variants: 37/Ventura I - initial production bomber version for the Royal Air Force, with capacity for 2,500 lbs of bombs and defensive armament including three pairs of .303 calibre machine guns, powered by Pratt & Whitney R-2800-S1A4G Double Wasp radials (188 built);
37/Ventura II - Ventura I with R-2800-31s (487 built, of which 264 delivered to the US Army Air Force without any US military designator and 27 to the US Navy as PV-3s);
137/Ventura IIA - lend-lease version (200 built, of which 112 went to US Army Air Force as B-34/B-34A Lexington, 45 to Canada, 23 to New Zealand and 20 to Australia);
137/Ventura GR.V - patrol bomber version for RAF, Australia, Canada, New Zealand and South Africa (387 built);
237/PV-1 - patrol bomber version for US Navy (1,113 built);
437/B-34 Lexington - armed reconnaissance version for US Army Air Force (18 built);
Vega 15/PV-2 - Re-engineered version optimised for maritime patrol with increased fuel capacity, larger wing, and larger bomb bay (500 built, the initial 30 as interim PV-2C; first flight 3 Dec 43);
Vega 15/PV-2D - PV-2 with increased forward-firing armament (35 built).
Conversions: Howard Super Ventura - aerodynamically improved version with all military characteristics removed and accommodation for up to 15 passengers (30 converted; first flight May 55);
Howard 500 - pressurised version of PV-1 with new systems, increased wing span, increased fuel capacity and accommodation for up to 14 passengers, powered by Pratt & Whitney R-2800CB-16 or -17 radials (approximately 25 converted; first flight Sep 59). The project was taken over in 1963 by Business Air Craft Corporation and re-designated BA-400, although only one further conversion was completed, for Firestone in 1964;
Howard 350 - developed version of the Super Ventura initially marketed as the Mark II Super Ventura, featuring additional improvements including vista windows, powered by R2800-83AM-10s (28 converted, some from Super Ventura; first flight 1 Apr 62).
In addition, around 50 Venturas and Harpoons were converted for agricultural operations; and 10 PV-2s were converted for aerial firefighting.