Fighting the U-boats
Lockheed Ventura and Harpoon
prepared by Emmanuel Gustin
In September 1939 Lockheed proposed to the British representatives a military development of the Lockheed 18 Lodestar, as a follow-up for Hudson. The Hudson itself had been hastily developed from the smaller Lockheed 14 Super Electra. But this time, a more extensive militarisation was proposed. In June 1940, the proposal was accepted, and 675 aircraft were ordered.
The Lodestar, the Super Electra and the Hudson were all powered by either the Wright R-1820 or the Pratt & Whitney R-1830, in the 1000hp to 1200hp class. But for the Ventura the Pratt & Whitney R-2800 Double Wasp was chosen, an engine in the 2000hp class. (The number in the designation indicates the cylinder volume in cubic inches.) This engine change implied that range was sacrificed for speed, and was prompted by a British decision to consider the Ventura as a medium bomber rather than as a maritime patrol aircraft.
The Ventura had an all-metal stressed-skin construction. The fuselage had an elliptical cross-section, but was less portly than that of the Hudson. The wing was built in three parts, the centre section constructed integral with the fuselage. Again, Fowler flaps of generous area were installed. The twin tailfins had the elliptical shape typical for Lockheed aircraft. Like the Hudson, the Ventura was provided with a dorsal turret, but it had a better field of fire. In addition, the lower rear fuselage was modified to create a step, so that a ventral gun position could be installed. Normally there was a crew of four: pilot, navigator / bomb aimer, radio operator / gunner, and turret gunner.
The Ventura had a high wing loading, and especially the later, heavier versions had a marginal take-off performance. Great care was required during take-off and landing. But it was fairly fast, especially at low level, and a fine aircraft to fly on instruments, in bad weather. The Ventura handled well with one engine out. While the Ventura was a superior combat aircraft than the Hudson, range was reduced. This was perhaps felt the most by the crews who had to make the transatlantic ferry flights: Even with extra fuel tanks added to a total of 1100 gallons, it could cross the Atlantic only with an average 25-knot tailwind.
Production of the Ventura was undertaken by Vega, a subsidiary of Lockheed, which later was completely integrated into Lockheed. The first one flew on 31 July 1941. Deliveries began in September. The Ventura Mk.I was powered by 1850hp R-2800-S1A4-G engines. Most Mk.Is reached the RAF, with the exception of 21 that were retained in Canada for use as trainers, and a few that were sent to South Africa. After 188 Mk.Is had been delivered, production switched to the Mk.II with 2000hp R-2800-31 engines and a redesigned bomb bay. After Pearl Harbour the US military seized all combat aircraft it could get, and of the 487 Mk.IIs built, 264 were taken over by the USAF and 27 by the US Navy, which called them PV-3. Although some US Venturas flew antisubmarine patrols, most were used as trainers. A number of Mk.IIs were retained in Canada, and over 100 were delivered to the South African Air Force. The next model was the Mk.IIA, which had American equipment and guns instead of British, because it was built to Lend-Lease contracts. The RAF received only 25, and 45 were sent to Canada. The balance was again impounded by the USAF, that called these aircraft B-34 Lexington. Most of them were modified to B-34A and B-34B standards, again for training purposes.
The first operational RAF squadron with Venturas was No.21, in May 1942. It was followed by No.464 (RAAF) and No.487 (RZNAF). All three participated in the first combat mission of the type, a low-level attack on the Philips factories at Eindhoven, in the Netherlands, on 6 December 1942. This was a disaster: Of the 47 Venturas 9 were shot down and only one escaped without damage. The Venturas switched to medium level bombing, but they were mediocre as bombers. In the summer of 1943 they were replaced by the Mosquito.
The Venturas were then converted to maritime patrol aircraft. The first Venturas GR Mk.I served with No.519 and 521 squadrons in the Atlantic, and No.13 and 500 in the Mediterranean. The Ventura began to replace the Hudson as maritime patrol aircraft.
The next version was powered by 1700hp Wright R-2600-13 engines. The USAF initially called it O-56, reflecting its purpose as a reconnaissance (Observation) aircraft. Before it flew, it was renamed B-37. The RAF called it Ventura GR Mk.III, but would receive none. Only 18 B-37s were built, because in the summer of 1942, the USAF agreed with the US Navy that the latter could take over land-based anti-submarine patrols, and acquire some land-based bombers. Part of the deal was that Lockheed would switch production from the B-34 and B-37 for the USAF, to the PV-1 for the Navy.
The PV-1 was very similar to the B-34, but it had reduced defensive armament and more fuel. The bomb bay was redesigned again, to enable the PV-1 to carry a torpedo. A radar was installed in the nose. A bomb aiming window was initially retained, but later deleted in favour of thee additional forward-firing machineguns in a pack under the nose. The PV-1 became the most built model, and the first of 600 flew on 3 November 1942. The PV-1s were extensively used in the Pacific. Because of its good performance and the lack of more suitable alternatives, the Ventura was also briefly used as a nightfighter.
More than half the production of the PV-1 was diverted to RAF and Commonwealth forces, where it was known as the Ventura GR Mk.V. It entered service at a time when the balance was shifting in favour of the Allied. Illustrative is the experience of U-960: It was spotted by two destroyers on 17 May 1944, in the western Mediterranean. The destroyers did not attack, but five destroyers were sent to the area, and about 70 aircraft were called on for support, most of them Wellingtons and Venturas. (This tactic was known as The Swamp. See page on U-371 for info). The next night, a Wellington GR Mk.XIV reestablished contact. U-960 was hunted by aircraft and chased by two destroyers throughout the next night. In the morning the destroyers reached her and attacked with depth charges. The submarine was forced to the surface, where she was bombed by a Ventura and shot at by the destroyers. It was quickly sunk. Only 20 of her crew of 51 were rescued.
The final twist in the development of the Ventura was a major redesign, the PV-2 Harpoon, first flown on 3 December 1943. The PV-2 had larger outer wing panels with integral fuel tanks, and a larger tailplane and tailfins. The bomb bay was redesigned again. The Harpoon could carry more bombs than the Ventura, and when a torpedo was carried it was now completely enclosed by the bomb bay doors. These changes were intended to make the aircraft more suitable as a patrol aircraft, by increasing range, at some cost in speed. Unfortunately, the original wing design was unsatisfactory. The first 69 aircraft, designated PV-2C, could only be used as trainers. A complete redesign of the wing cured the problem, but only 35 aircraft could be delivered before the end of the war.
U-boats sunk by this aircraft type (Ventura)
Lockheed Ventura Mk.I Two 1850hp Pratt & Whitney R-2800-S1A4-G radial engines Wing span 19.96m, length 15.67m, height 3.37m, wing area 51.2m2. Empty weight 7824kg, max take-off weight 11804kg. Max. speed 502km/h at 4725m. Cruising speed 434km/h. Service ceiling 7620m. Normal range 1490km. Armament: Dorsal turret with two .303 guns, later increase to four. Two .303 guns in the ventral position. Two fixed forward- firing .50 guns in the nose decking, and two flexible .303 guns in the nose. Bombs load up to 2500lb (1135kg).
Lockheed PV-1 Ventura Two 2000hp Pratt & Whitney R-2800-31 radial engines Wing span 19.96m, length 15.77m, height 3.63m, wing area 51.19m2. Empty weight 9161kg, max take-off weight 14096kg. Max. speed 518km/h at 4205m. Service ceiling 8015m. Normal range 2190km. Armament: Dorsal turret with two .50 guns. Two .30 guns in the ventral position. Two fixed forward-firing .50 guns in the nose decking. Bombs up to 1361kg, or six 147kg depth charges, or a torpedo.