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65-786: The Lockheed Ventura is a twin-engine medium bomber and patrol bomber of World War II. The Ventura first entered combat in Europe as a bomber with the RAF in late 1942. Designated PV-1 by the United States Navy (US Navy), it entered combat in 1943 in the Pacific. The bomber was also used by the United States Army Air Forces (USAAF), which designated it the Lockheed B-34 ( Lexington ) and B-37 as

130-459: A Mk.6 head with inert lead ballast and was fitted with four Mark 21 (aluminum construction) or 33 (steel) tracking flares, 10 inches long by 1 inch wide and carrying 100 grams of pyrotechnic mixture, to provide a strong IR signature for the Sidewinder to lock onto. Carried paired with AIM-9s on AERO-3B launchers, a pilot would fire the rocket, then switch to his Sidewinder, wait for it to acquire

195-875: A PV-2 executive aircraft conversion dubbed Centaurus starting in 1958. The cost of the conversion was $ 155,000 in addition to the airframe. The Portuguese Air Force received 42 Lockheed PV-2C Harpoons from 1953, which replaced the Curtiss SB2C-5 Helldiver as an anti-submarine aircraft. The Harpoons equipped squadrons 61 and 62 at the Montijo Air Base . In 1960, the Harpoons were replaced as maritime patrol and anti-submarine aircraft by Lockheed P2V-5 Neptunes . The remaining Harpoons were sent to Angola and Mozambique , where they formed Squadron 91 operating from Luanda Air Base and Squadron 101 from Beira Air Base. The Harpoons were used on operations in

260-513: A bombardier's position, which was deleted in the PV-2. Some other significant developments included the increase of the bombload by 30% to 4,000 lb (1,800 kg), and the ability to carry eight 5-inch (127 mm) HVAR rockets under the wings. While the PV-2 was expected to have increased range and better takeoff, the anticipated speed statistics were projected lower than those of the PV-1, due to

325-525: A combined rocket weight of 5,800 pounds (2,600 kg). In April 1945, HVAR rockets were used in Operation Bumblebee in the Navy's facility on Island Beach, New Jersey . The HVAR rockets launched 6-inch (150 mm) ramjet engines from wooden frames, accelerating the carbon disulfide fuel ramjets to flight speed. On 13 June, the ramjets achieved supersonic speed. HVAR rockets were used in

390-823: A further 375 later in 1940. Lockheed needed more production capacity and nearby Vega Aircraft Corporation was contracted for building the Ventura. The Ventura was very similar to its predecessor, the Lockheed Hudson . The primary difference was not in layout; rather, the Ventura was larger, heavier, and used more powerful engines than the Hudson. The RAF ordered 188 Venturas in February 1940, which were delivered from mid-1942. Venturas were initially used for daylight raids on occupied Europe but, like some other RAF bombers, they proved too vulnerable without fighter escort, which

455-927: A good instinctive sense for the range to the target. HVARs were widely used in the Korean War . Douglas AD-1 Skyraiders often carried a dozen HVARs, and sometimes an additional pair of much larger but less accurate Tiny Tim 11.75-inch (29.8 cm) rockets. Targets included ships, bunkers, pillboxes, coastal defense guns, ammunition dumps, and occasionally even destroyers and major bridges. Numerous North American F-51D Mustang "Six-Shooters" (six .50 cal (12.7 mm) machine guns plus six HVARs and 2 bombs or ten HVARs) and carrier-based Grumman F9F Panther jets flew close air support in Korea. Panthers carried 6 HVARs and four 20mm cannons , while both planes could carry an additional pair of 500 lb (230 kg) bombs, napalm, or fuel tanks. Neil Armstrong and John Glenn were among

520-428: A million HVARs were made during World War II, and production continued until 1955. HVARs remained in the Navy's inventory until the mid-1960s. After World War II, newer versions included a new general purpose type with a proximity fuse , white phosphorus smoke rounds, an anti-submarine head, and a new shaped-charge warhead for use against tanks. The 6.5-inch (170 mm) RAM rocket was an oversized shaped-charge head on

585-771: A navalized version, the PV-1 Ventura . The PV-1 began to be delivered in December 1942, and entered service in February 1943. The first squadron in combat was VP-135, deployed in the Aleutian Islands in April 1943. They were operated by three other squadrons in this theatre. From the Aleutians, they flew strikes against Paramushiro, a Japanese island. Often, PV-1s would lead B-24 bomber formations, since they were equipped with radar. In late 1943, PV-1s were deployed to

650-433: A nominal load of 8,000 pounds (3,600 kg) or more, and light bombers carried up to 2,000 lb (907 kg). These distinctions were beginning to disappear by the middle of World War II, when the average fighter aircraft could now carry a 2,000 lb (907 kg) bombload. Advances in powerplants and designs eventually allowed light bombers , tactical bombers , and later jet fighter-bombers to take over

715-502: A pack with three 0.50 inch (12.7 mm) machine guns underneath the nose. These aircraft could also carry eight 5-inch (127 mm) HVAR rockets on launchers underneath the wings. The PV-1 began to be delivered in December 1942, and entered service in February 1943. The first squadron in combat was VP-135, deployed in the Aleutian Islands in April 1943. They were operated by three other squadrons in this theatre. From

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780-537: A power station in Amsterdam . The squadron was told that the target was of such importance to Dutch morale, that the attack was to be continued regardless of opposition. Significant problems developed with rendezvousing with the escorting fighters, with the result that all 10 Venturas that crossed the coast were lost to German fighters. Squadron Leader Leonard Trent (later the last of the Great Escapers ) won

845-700: A round cavity, the number depending on motor diameter. The central hole in a tubular charge makes it more difficult to extrude, requiring a softer propellant blend that also yields somewhat lower performance. Rocket ∆V increased from 216 m/s (710 ft/s) for the 5-inch AR to 420 m/s (1,400 ft/s) for HVAR, giving the coveted flatter trajectory. Two different versions of the HVAR were built during World War II . The warheads were Mk 4 general purpose warheads holding 7.6 pounds (3.4 kg) of TNT with base and optionally nose fuses; or Mk. 2 AP warheads with 2.2 pounds (1.00 kg) of Explosive D . HVAR testing

910-430: A standard HVAR motor as well. HVAR was an effective weapon in the hands of skilled, experienced pilots. It was less effective in the hands of average or inexperienced pilots who were accustomed to taking less careful aim and then "walking in" their gunfire to finally engage a target. HVARs could be fired in pairs or a single rapid-fire salvo but required accurate initial alignment and careful attention to range, or at least

975-673: A total of 286 aircraft. The SAAF also received some 135 PV-1s, which were used to protect shipping around the Cape of Good Hope and to bomb Italian shipping in the Mediterranean. In December 1942 four SAAF Venturas dropped supplies to survivors of the Dunedin Star shipwreck on South-West Africa 's Skeleton Coast . Venturas served in the South African Air Force until 1960. A few US Navy PV-1s force-landed in

1040-645: A trainer. British Commonwealth forces also used it in several guises, including antishipping and antisubmarine search and attack. The Ventura was developed from the Lockheed Model 18 Lodestar transport, as a replacement for the Lockheed Hudson bombers then in service with the Royal Air Force . Used in daylight attacks against occupied Europe, they proved to have weaknesses and were removed from bomber duty and some used for patrols by Coastal Command . After USAAF monopolization of land-based bombers

1105-525: Is no longer used, development of aircraft that fulfil a 'medium bomber' mission in all but name continued and these have been employed in various post-World War II conflicts; examples include dedicated tactical bombers such as the Su-24 , Su-34 , F-111 , J-16 and F-15E which have greater payload and range capability than fighter-bombers, but less than heavier strategic bombers. HVAR The High Velocity Aircraft Rocket , or HVAR , also known by

1170-567: The Angolan and Mozambican theatres of the Portuguese Overseas War (1961–1974). They served mainly as light bombers and ground attack aircraft, with occasional reconnaissance, transport and maritime patrol sorties. The last Portuguese Harpoons were retired in 1975. The Museu do Ar (Portuguese Air Museum) has what is believed to be the only remaining Lockheed PV-2C Harpoon in Europe. The first Ventura Mark Is were accepted by

1235-721: The English Electric Canberra (along with its derived U.S. counterpart, the Martin B-57 ) and the Soviet Ilyushin Il-28 "Beagle". Subsequent to World War II, only the U.S. Strategic Air Command ever used the term "medium bomber" in the 1950s to distinguish its Boeing B-47 Stratojets from somewhat larger contemporary Boeing B-52 Stratofortress "heavy bombers" in bombardment wings (older B-29 and B-50 heavy bombers were also redesignated as "medium" during this period). This nomenclature

1300-530: The Lockheed PV-2 Harpoon bomber. HVAR could penetrate 4 ft (1.2 m) of reinforced concrete and was used to sink transports, knock out pillboxes and AA gun emplacements, blow up ammo and oil-storage dumps, and destroy tanks, locomotives, and bunkers. Navy F4U Corsairs and TBF/TBM Avengers made the most extensive use of the rockets in the Pacific theater after the victory in Europe. Over

1365-632: The Miller Brewing Company and grandson of founder Frederick Miller . The company plane was bound for Winnipeg , Manitoba , but had trouble with both engines and crashed shortly after takeoff from Mitchell Field in Milwaukee , Wisconsin . Also killed were his oldest son, 20-year-old Fred, Jr., and the two company pilots, Joseph and Paul Laird. Oakland Airmotive (later Bay Aviation Services, based in Oakland, California) also offered

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1430-712: The Royal Air Force (RAF) in September 1941, with aircraft being delivered to Britain from April 1942. By the end of August, enough Venturas had arrived to equip No. 21 Squadron RAF , No. 487 Squadron RNZAF and No. 464 Squadron RAAF . The Ventura flew its first operational mission for the RAF on 3 November 1942, when three Venturas of 21 Squadron attacked railway targets near Hengelo in the Netherlands . On 6 December 1942, 47 Venturas from 21, 464 (RAAF) and 487 (RNZAF) squadrons participated in Operation Oyster ,

1495-601: The Ventura G.R.I. and 387 PV-1s were used by the RAF as the Ventura G.R.V in the Mediterranean and by Coastal Command. Some RAF aircraft were modified into Ventura C.V transport aircraft. A small number of Venturas were also used in other air forces, including the RCAF, RNZAF and SAAF. In the United Kingdom, No. 464 Squadron RAAF formed (mixture of Commonwealth personnel) at RAF Feltwell in September 1942 to operate

1560-598: The Victoria Cross for his leadership in this raid. The Ventura was never very popular among RAF crews. Although it was 50 mph (80 km/h) faster and carried more than twice the bomb load of its predecessor, the Hudson , it proved unsatisfactory as a bomber. By the summer of 1943, the Ventura had been replaced by the de Havilland Mosquito. The last Ventura raid was flown by 21 Squadron on 9 September 1943. Some Venturas were modified to be used by Coastal Command as

1625-407: The 1950s and 1960s as high-speed executive transports. The earliest conversions, called Super Venturas , incorporated a 48 in (122 cm) fuselage stretch, extra fuel tankage, large picture windows, luxury interiors, and weapons bays transformed into baggage compartments. The landing gear was swapped for the heavier-duty units from the PV-2. Later conversions, of which eighteen were completed in

1690-463: The 1960s, were called Howard 350 s. At least nineteen PV-1s were further modified, including cabin pressurization under the designation Howard 500 . A final PV-1 modification by Howard was the Eldorado 700 , with longer wings, a pointed nose, and streamlined engine cowlings. A notable crash of a civilian version occurred on December 17, 1954, killing four, including Fred Miller , president of

1755-502: The 1970s, the Mk.32 HEAT round being used by Air Force A-1E Skyraiders in Vietnam. Initial WW2 HVAR warheads were modified 5"/38 caliber gun shells, with the Mk.6 head being a modification of AA Common shells and the Mk.2 being derived from Special Common rounds. Later heads were purpose-built. The Mark 6 HE head came in two variations, Mod 0 and Mod 1. Mod 1 had a deep nose cavity to fit

1820-579: The Aleutians, they flew strikes against bases in Paramushiro and Shimushu , Japanese islands in the Kurile chain . Often, PV-1s would lead B-24 bomber formations, since they were equipped with radar. In late 1943, some PV-1s were deployed to the Solomon Islands as night fighters with VMF(N)-531 , a Marine Corps fighter squadron. The PV-2 Harpoon was a major redesign of the Ventura with

1885-676: The M403 VT fuze and thus carried 0.5lb less explosive fill. A head assembled with a motor is known by a separate designation listed below. Some surviving HVAR rockets were converted to training targets for pilots to practice firing AIM-9 Sidewinder infrared-guided missiles. Known as the TDU-11/B to the US Air Force and Target Rocket Mark 26 Mod 0 to the US Navy , it was heavier than the base rocket at about 215lb. The target rocket used

1950-479: The PV-1 was increased from 1,345 gal (5,081 L) to 1,607 gal (6,082 L), to increase its range; the forward defensive armament was also reduced for this reason. The most important addition was of an ASD-1 search radar. Early production PV-1s still carried a bombardier's station behind the nose radome, with four side windows and a flat bomb-aiming panel underneath the nose. Late production PV-1s dispensed with this bombardier position and replaced it with

2015-455: The PV-2 into service. The PV-2s already delivered were used for training purposes under the designation PV-2C. By the end of 1944, only 69 PV-2s had been delivered. They finally resumed when the redesign was complete. The first aircraft shipped were the PV-2D, which had eight forward-firing machine guns and was used in ground attacks. When World War II ended, all of the order was cancelled. With

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2080-492: The Panther pilots. It was in Korea that HVARs and Tiny Tims bridged the gap between prop planes and jets: Lockheed F-80C Shooting Star , Republic F-84E Thunderjet , Grumman F9F Panther , and North American F-86 Sabre . Jets gave the fighter pilots improved forward visibility. F-84E Thunderjets proved to be the most capable load-lifting fighter/bombers in Korea, demonstrating an ability to loft up to 24 HVARs and 2 Tiny Tims with

2145-435: The RAF were transferred to the U.S. Army Air Force. Though some were used as anti-submarine patrol bombers under the designation B-34 Lexington , most were used for training with various stateside units. Twenty-seven of these were used by the U.S. Navy for anti-submarine patrols as well; these were designated PV-1 Ventura and PV-2 Harpoon. During the early months of 1942, the primary responsibility for anti-submarine warfare in

2210-659: The Solomon Islands and to the newly captured field at Tarawa in the Gilbert Islands . After the war, the U.S. Navy deemed many PV-1s obsolete and the aircraft were sent to Naval Air Station Clinton , Oklahoma to be demilitarized and reduced to scrap. Lokheed PV-1 Ventura Harpoon m.m.80074 – Museo Piana delle Orme - Latina - Italy Data from General characteristics Performance Armament Aircraft of comparable role, configuration, and era Related lists Medium bomber The term

2275-659: The Soviet Union after attacking Japanese targets on the Kurile islands and were impounded. Some of them were repaired and pressed into service by the Soviet Air Force where the type became known as the B-34. By December 1944, eight planes were located on airfields on Kamchatka: four were fully airworthy, three were undergoing repairs and one was a write-off. By 1945 seven PV-1s (five of them being airworthy) were used by

2340-668: The Soviets, one plane was the personal liaison aircraft of Ltc M.A. Yeryomin. The planes were used during the Soviet-Japanese campaign in August 1945. After the end of the war only one aircraft remained in service. From August 1942, 487 Squadron RNZAF, (operating in Europe as part of the RAF), was equipped with the type, although losses (including on 3 May 1943 the loss of all 11 aircraft attacking Amsterdam), led to their replacement with

2405-580: The USAAF, which placed its own order for 200 Ventura Mark IIA as the B-34 Lexington , later renamed RB-34 . In August 1941, large orders for Venturas were placed with Lend-Lease Act money. Among the orders were for 550 armed reconnaissance versions of the Ventura. This aircraft was originally planned to be built under the designation O-56 . The main differences between the Ventura and the O-56 were in

2470-587: The United States was shouldered by the Army Air Forces. This irked the Navy, as it considered this region of battle its burden. To carry out such a task, the Navy was pursuing a long-range, land-based patrol and reconnaissance aircraft with a substantial bomb load. This goal was always resisted by the Army Air Forces, which carefully protected its monopoly on land-based bombing. This forced the navy to use long-range floatplanes for these roles. The Navy

2535-475: The Vega Aircraft Company division of Lockheed (hence the "V" Navy manufacturer's letter that later replaced the "O" for Lockheed), was a version of the Ventura built for the U.S. Navy (see Venturas in U.S. Navy service below). The main differences between the PV-1 and the B-34 were the inclusion of special equipment in the PV-1, adapting it to its patrol bombing role. The maximum fuel capacity of

2600-526: The Ventura as part of 2 Group , Bomber Command; it converted to the de Havilland Mosquito in September 1943. In the Mediterranean, No. 459 Squadron RAAF was equipped with the Ventura V between December 1943 to July 1944, flying mainly anti-submarine and anti-shipping patrols. In Australia, 55 PV-1s were supplied to the RAAF for use in the South West Pacific Area . No. 13 Squadron RAAF was

2665-655: The action. The pilot, Flying Officer D. Ayson and navigator, Warrant Officer W. Williams, were awarded the DFC. The dorsal turret gunner Flight Sergeant G. Hannah was awarded the DFM. By late 1944 the Ventura began to be phased out of frontline action as the RNZAF backed away from the Patrol Bomber concept, orders for PV-2 Harpoons were canceled after a handful of aircraft had been delivered. At VJ Day only 30 PV-1 aircraft remained on

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2730-569: The allied advance to Emirau and Green Island and to New Britain . RNZAF Venturas were tasked with routine patrols, anti-shipping strikes, minelaying, bombing and strafing missions, air-sea rescue patrols, and photographic reconnaissance missions. RNZAF machines often clashed with Japanese fighters, notably during an air-sea rescue patrol on Christmas Eve 1943. NZ4509 was attacked by nine Japanese single-engine fighters over St. George's Channel. It shot down three, later confirmed, and claimed two others as probable, although it suffered heavy damage in

2795-453: The de Havilland Mosquito in June. The Royal New Zealand Air Force in the Pacific received 139 Venturas and some Harpoons from June 1943 to replace Lockheed Hudsons in the maritime patrol bomber and medium bomber roles. Initially Venturas were unpopular with the RNZAF due to rumoured poor performance on one engine, the fate of Squadron Leader Leonard Trent VC of 487 Squadron (above) as well as

2860-464: The engines: rather than the 2,000 hp (1,491 kW) Pratt & Whitney R-2800 radials of the Ventura, the O-56 used 1,700 hp (1,270 kW) Wright R-2600 -13 radials. Before completion of the first O-56, the U.S. Army Air Forces dropped the "O-" category used to designate "observation" (reconnaissance) aircraft. The O-56 was redesignated the RB-34B (the R denoted 'restricted' meaning it

2925-603: The failure of the U.S. to provide New Zealand with promised B-24 Liberators . Despite that the RNZAF Venturas came to be among the most widely used of any nation's, seeing substantial action until VJ Day over South West Pacific islands. The first 19 RB-34s that arrived by sea from the U.S. in June had much equipment either missing or damaged. Six airworthy machines were hurriedly produced by cannibalization and sent into action with No. 3 Squadron RNZAF in Fiji . On 26 June

2990-481: The first PV-1s were flown to Whenuapai and No. 1 Squadron RNZAF was able to convert to 18 of these by 1 August, then replacing the mixed 3 Squadron in action at Henderson Field , Guadalcanal in late October. By this time No. 2 Squadron RNZAF at Ohakea and No. 9 Squadron RNZAF were also using the type. The following year No. 4 Squadron RNZAF and No. 8 Squadron RNZAF also received Venturas. Some squadrons were retained on garrison duty while others followed

3055-533: The flatter trajectory of a faster rocket spurred the rapid development. HVAR had a constant 5-inch diameter for both warhead and rocket motor, increasing propellant from 8.5 to 23.9 pounds (3.9 to 10.8 kg) of Ballistite . U.S. Ballistite propellant had a sea level specific impulse of over 200 seconds (2.0 km/s), compared with about 180 seconds (1.8 km/s) for the British Cordite , German WASAG and Soviet PTP propellants. Hercules Powder Company

3120-539: The front-line with No. 3 Squadron at Jacquinot Bay . Planned re-equipment with de Havilland Mosquitos did not take place until after the cessation of hostilities. The last Ventura unit was No. 2 Squadron, which continued to operate PV-1 and PV-2 aircraft on meteorological duty until 1948. A restored RNZAF RB-34 (NZ4600) is owned by the Museum of Transport and Technology in Auckland . Some 264 Ventura Mark IIs ordered by

3185-521: The home defence coastal patrol role in both Eastern and Western Air Command. They were flown by 8, 113, 115, 145, and 149 Squadrons. A further 21 Ventura Mk. Is and 108 Ventura Mk. IIs were used in a training role at 1 Central Flying School, Trenton, Ontario, and at RCAF Station Pennfield Ridge, New Brunswick (RAF No. 34 Operational Training Unit) as part of the BCATP . A total of 21 Mk. Is, 108 Mk. IIs, and 157 G.R. Mk. Vs were in service during this period for

3250-604: The large daylight 2 Group raid against the Philips radio and vacuum tube factories at Eindhoven . Also committed to the raid were 36 Bostons and 10 de Havilland Mosquitos . Carrying incendiaries, they were placed in the third wave of aircraft, and suffered the highest rate of loss. Nine of the 47 Venturas were shot down and many others were damaged by flak or bird strikes. The force also lost four Bostons and one Mosquito. Six months later, on 3 May 1943, Venturas of 487 Squadron RNZAF were sent on Operation Ramrod 16 , an attack on

3315-509: The nickname Holy Moses , was an American unguided rocket developed during World War II to attack targets on the ground from aircraft. It saw extensive use during both World War II and the Korean War . The HVAR was designed by engineers at Caltech during World War II as an improvement on the 5-Inch Forward Firing Aircraft Rocket (FFAR), which had a 5-inch (127 mm) diameter warhead but an underpowered 3.25-inch (83 mm) diameter rocket motor. The desire for improved accuracy from

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3380-590: The only operational squadron in Australia equipped with the Ventura. It operated primarily in north-eastern Queensland and then the Northern Territory , and later serving in the Borneo campaign of 1945 . After the war, the squadron used its aircraft to help transport liberated prisoners of war . A total of 157 Ventura G.R. Mk. Vs were used operationally by the RCAF from 16 June 1942 to 18 April 1947 in

3445-501: The roles performed by mediums. After the war, use of the term generally vanished; some of this was due to mass demobilization of the participant air forces' existing equipment, and the fact that several of the most-produced medium bomber types were now technologically obsolescent. Although a number of later aircraft were designed in this performance and load-carrying range, they were henceforth referred to as tactical bombers or strike aircraft instead. Examples of post-war mediums include

3510-510: The time. Some of these bombers, such as the Heinkel He 111 , Junkers Ju 86 , Savoia-Marchetti SM.79 , Douglas B-18 , and Armstrong Whitworth Whitley were developed from or in conjunction with existing airliners or transport aircraft. The World War II-era medium bomber was generally considered to be any level bomber design that delivered about 4,000 pounds (1,800 kg) of ordnance over ranges of about 1,500 to 2,000 mi (2,400 to 3,200 km). Typical heavy bombers were those with

3575-411: The use of the same engines but an increase in weight. The Navy ordered 500 examples, designating them with the popular name Harpoon . Early tests indicated a tendency for the wings to wrinkle dangerously. As this problem could not be solved by a 6 ft (1.8 m) reduction in wingspan (making the wing uniformly flexible), a complete redesign of the wing was necessitated. This hurdle delayed entry of

3640-419: The wing area increased from 551 ft (51.2 m) to 686 ft (63.7 m) giving an increased load-carrying capability, and which first flew on 3 December 1943. The motivation for redesign was weaknesses in the PV-1, which had shown itself to have problems in taking off when carrying a full load of fuel. On the PV-2, the armament became standardized at five forward-firing machine guns. Many early PV-1s had

3705-439: The wing problems fixed, the PV-2 proved reliable, and eventually popular. It was first used in the Aleutians by VP-139, one of the squadrons that originally used the PV-1. It was used by a number of countries after the war's end, but the United States ceased ordering new PV-2s, and they were all soon retired from service. Ex-military PV-1 Venturas from Canada and South Africa were converted by Howard Aero in San Antonio, Texas , in

3770-465: Was complete by D-Day , 6 June 1944, and air-lifted Navy HVAR rockets were soon being loaded on Ninth Air Force Republic P-47D Thunderbolts to support the break-out at Normandy. Other single-engine delivery aircraft included the Vought F4U Corsair , Grumman F6F Hellcat , Grumman TBF/TBM Avenger , and Curtiss SB2C Helldiver . Twin-engine aircraft sometimes armed with HVARs included the Lockheed P-38 Lightning , North American PBJ Mitchell bomber and

3835-417: Was difficult to provide for long-range missions. Venturas were replaced by the faster de Havilland Mosquito . The Venturas were transferred to patrol duties with Coastal Command as the Mosquito replaced them in bomber squadrons; 30 went to the Royal Canadian Air Force (RCAF) and some to the South African Air Force (SAAF). The RAF placed an order for 487 Ventura Mark II s but many of these were diverted to

3900-452: Was not to be used for combat). Before the first of these flew, the design was redesignated again as the B-37 with a higher powered version of the R-2600, later it also was designated the RB-37 . While 550 were ordered by the Army Air Forces, acquisition by the USAAF stopped after only 18 Venturas were accepted, when the Army Air Forces agreed to turn over exclusive use of the Ventura to the United States Navy . The PV-1 Ventura , built by

3965-406: Was purely semantic and bureaucratic, however as both the B-47 and B-52 strategic bombers were much larger and had far greater performance and load-carrying ability than any of the World War II-era heavy or medium bombers. Similarly, the Royal Air Force referred at times to its V bomber force as medium bombers, but this was in terms of range rather than load-carrying capacity. Although the term

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4030-463: Was removed, the US Navy ordered a revised design which entered service as the PV-2 Harpoon for anti-submarine work. At the start of the war, Lockheed proposed military conversions of the Lodestar for the RAF as replacement for the Hudson reconnaissance aircraft and the Bristol Blenheim bomber. The first British order was placed in February 1940 for 25 Model 32 as bombers. This was followed by an order for 300 Model 37 with Double Wasp engines, then for

4095-508: Was the principal U.S. supplier of high performance extruded Ballistite propellants: 51.5% nitrocellulose , 43% nitroglycerine , 3.25% diethyl phthalate , 1.25% potassium sulfate , 1% ethyl centralite , and 0.2% carbon black . The propellant in U.S. 3.25-inch and 5-inch rocket motors consisted of a single large X-shaped cross-section, "cruciform" Ballistite grain cavity. This went against the common practice of filling rocket motors with different numbers of smaller same-sized tubular charges with

4160-487: Was unable to upgrade to more capable aircraft until the Army Air Forces needed the Navy plant in Renton, Washington to manufacture its Boeing B-29 Superfortress . In exchange for use of the Renton plant, the Army Air Forces would discontinue its objections to Naval land-based bombers, and provide aircraft to the Navy. One of the clauses of this agreement stated that production of the B-34 and B-37 by Lockheed would cease, and instead these resources would be directed at building

4225-617: Was used prior to and during World War II , based on available parameters of engine and aeronautical technology for bomber aircraft designs at that time. After the war, medium bombers were replaced in world air forces by more advanced and capable aircraft. In the early 1930s many air forces were looking to modernize their existing bomber aircraft fleets, which frequently consisted of older biplanes . The new designs were typically twin-engined monoplanes , often of all-metal construction, and optimized for high enough performance and speed to help evade rapidly evolving fighter aircraft designs of

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