Post by Tony on Jun 8, 2012 20:17:49 GMT 12
Just received this in an email from an OZ colleague.
"Wings of Time" # 12. Part One.
The Lockheed-Vega PV-1 Ventura/B-34 Lexington and PV-2 Harpoon.
Should you prefer, you may like to click on the Link below to read this on my archive section. The images are somewhat larger. There is stuff here going back to 2009.
www.aerohub.co.nz/category/chronicles/
or
www.aerohub.co.nz/2012/06/wings-of-time-12-part-one/
A review by Mike Feeney with the emphasis being placed on the technical, operational and handling aspects of this controversial patrol bomber.
New Zealand has a long history of operating Lockheed aeroplanes from the 1930s up until the present. There have been the L-10 Electra, the smaller L-12 Electra Junior, L-14 Super Electra/ Hudson, L-18 Lodestar, PV-1 Ventura, L-188 Electra and, currently, the C-130 Hercules and P-3 Orion.
The Ventura was, until the Canberra, the RNZAF’s heaviest and most powerful bomber type. It has been maligned by some, in my opinion unfairly. The high losses incurred by 487 (NZ) Squadron during their daylight raids on targets in Holland were due to operational factors with respect to escorting Spitfires becoming entangled with Bf109s at higher levels and far from the Venturas which they were supposed to be protecting. Most of the 487 aircraft were shot down before reaching the target power stations and the recall radio message was either not heard or was ignored.
But regardless of the causal factors for the ghastly losses, no type, with the possible exception of the DH Mosquito, could have survived concentrated defence by fighters such as the Bf109 and Fw190. The result would have been the same had the aircraft used been the B-25 Mitchell, A-20 Havoc/Boston or Martin B-26 Marauder. At full power a clean Ventura, at 280 knots true airspeed (TAS) (225 knots indicated airspeed) at 15,000 feet was actually somewhat faster than all of those types.They all cruised at a similar TAS, depending on the phase of the mission profile; 160 – 200 knots TAS. The maximum level TAS figures vary with different variants but, with respect to vulnerability to AA fire and attack by fighter aircraft, are of no significance. It mattered not to the pilot of a Fw190 or Bf109 if an Allied aircraft was trying to escape at 250 or 280 knots. The max. diving speed (Vne) IAS for a clean PV-1 is 375 mph (325 knots).
NOTE TO THE PHOTOGRAPH BELOW: I found this faded photograph which I believe to be of RNZAF NCOs who were with No. 487 (NZ) Squadron in early 1943 at RAF Station Methold. I don’t know who took it and I have no names of the chaps. Perhaps a reader will recognise a familiar face?
In the operational area of the RNZAF Venturas, their principal fighter threat came from the Nakajima Ki-43 ‘Oscar’ or the Mitsubishi A6M Zero/Zeke, which were based at the Rabaul airstrip and some other nearby strips in East New Britain. By the time RNZAF Venturas were moved to the main Piva airfield on Bougainville in 1944 the number of Japanese fighters was much reduced due to the intense bombing and strafing raids on the Japanese airfields. The USAAF and US Marine Corps units were moving west, leaving the small RNZAF forces to help ‘mop up’ the remaining isolated enemy ground troops. The extremely agile Ki-43 had two 12.7mm machine-guns mounted on the upper fuselage so posed a threat to the Ventura…if it had an altitude advantage as the Oscar’s maximum level speed was only 280 knots. The Mitsubishi A6M Zero was marginally faster at 290 knots. A clean, light Ventura, at max. power, particularly if it had altitude to trade, could almost outrun an Oscar or Zero and if Japanese pilots decided to pursue from astern at a slow closing rate, they became very vulnerable to either the Ventura’s upper or belly guns.
Notes to the map below: To put some sort of scale to this simplified map, I think the distance from Port Moresby to Bougainville is about 550 nautical miles; from memory about 2.5 hours in a Fokker F-27 or 4.0 hours in a DC-3. The little island group directly nor-west of Bougainville is where the Green Island WWII airfield was. Directly west of there is Rabaul; the Japanese HQ. The longitude of the sou-east end of Bougainville is 156 East and the border between the PNG mainland and the Indonesian held West Papua runs down 141 East which makes the length of PNG about 900 nautical miles. The Equator is a little north of the Admiralty Islands. The main aerodrome is on Manus island which was a large US base during WWII. It was there that a huge fleet of US ships assembled in preparation for the invasion of the Philippines. And of course it was during the Battle of the Bismarck Sea that USAAF and RAAF aircraft destroyed the large Japanese supply convoy. A particularly historic region indeed.
The RNZAF operated 82 PV-1s, 57 B-34s and inherited 4 PV-2 Harpoons later in the war. They were flown by Squadron No.s 1, 2, 3, 4, 8, 9 and No.1 Operational Training Unit. Their operational theatre was almost entirely in the South-West Pacific from Guadalcanal to Bougainville and Green Island which is between Bougainville and the Japanese base at Rabaul, at the eastern end of New Britain, New Guinea. The RNZAF had also received 94 Lend-lease Hudsons and 4 Lodestars.
Some 40 RNZAF Venturas were destroyed or written-off as beyond repair or broken down to spares due to enemy action, training accidents or non-combat accidents in the field; mainly take-off or landing mishaps.
Notes to the map below: The island called Nissan is also known as Green Island. The Piva airfields where RNZAF aircraft were based were on the coastal flats near Torokina. Just a few miles from Buin is where Admiral Yamamoto’s Betty bomber was intercepted and shot down by Lockheed P-38s from Henderson Field, Gaudalcanal. The last time I was around the area, Mount Bagana was fairly active. I really enjoyed being based at Rabaul and came to know the region well. Buka and Kieta were the main airstrips but there were others which could take a DC-3 such as Buin and Wakunai. Extensive coconut plantations covered much of the coastal areas of all islands. The huge copper mine was inland from Kieta.
The Ventura programme was initiated in conjunction with the British who asked Lockheed for an upgraded version of the Hudson, which the RAF were already using in the maritime patrol role.. The Vega division of Lockheed used the L-18 Lodestar as the basis for the redesign. The Lodestar was simply a stretched-fuselage version of the L-14 ‘Super Electra’/Hudson. Other than the lengthened fuselage to permit two more seat rows, it was virtually identical to the L-14. The Model 237-27-01 first flew on 31st July, 1941 with deliveries to the RAF commencing in September 1941. Other British Commonwealth air forces also used them such as Canada, Australia and South Africa and the US Navy and USAAF operated many in different variants. The PV-1 and the later PV-2 also found their way to a large number of other countries.
Before considering the Ventura’s handling reputation, it is important to understand some details of the type. First its wing and flaps as they are the key factors involved.
The Ventura’s highly tapered wing spans 65′ 6″ and has a zero-flap area of just 551 square feet. When the huge Fowler flaps are fully extended the area increases to 619 square feet. In order to enhance aileron authority at low airspeed, and when on one engine, three leading-edge slots are integral in each outer wing.
The single mainspar runs through the fuselage while the front and rear spars are attached to the fuselage. There are four fuel tanks in the centre-section plus one in each wing outboard of the engines. Their capacities are (Ventura I and II): Front mains 94 Imp. gallons per side. Rear mains 107 Imp. gallons per side. Auxillaries (outer wing) 34 Imp. gallons per side. Total for standard wing tank fit 470 Imp. gallons. Fuel jettison valves were fitted to the left front, left rear and right front tanks.Two fuselage tanks could also be fitted. Under-wing drop-tanks could replace the bombs.
The main undercarriage retracts rearwards and the tailwheel retracts. The gear, brakes, bomb-bay doors and the Sperry autopilot are hydraulically actuated as are the flaps via a system of cables which move the flaps along their tracks.
To put the wing into perspective, it is 30 feet shorter than that of a DC-3 and its area is 400 square feet less. As Venturas operated at similar weights to the military C-47, the wing loading, at 55 lbs/sq. ft. was about double that of the C-47.
The Lodestar fuselage was widened and deepened in order to fit a bomb-bay which could accept 3,000 lbs of bombs, or 6 x 325 lb depth-charges or a torpedo. Extra bomb-bay fuel tanks could also be installed for very long ferry/patrol flights. A ventral gun position with 2 x 0.303 machine-guns was fitted. The upper powered turret had 2 x 0.303s also. The initial nose section had side windows and a flat lower window for a bomb-aimer and sight. 2 x 0.303s were located in a flexible mount. Later variants had a ‘solid’ nose to allow a battery of 0.50 machine-guns to be fitted. Other models had the 0.303″ guns replaced with 0.50″ machine-guns.
The tailplane and fin/rudder assembly remained as per the Lodestar which meant an increase in the minimum control speed in the air (Vmca), as compared to the Lodestar or Hudson with their 1,200 bhp R-1820 Wright Cyclones. More on handling later.
The basic specifications of the PV-1/B-34 models used by the RNZAF follow. Bear in mind that variations in areas such as weights occurred in the field and in the literature so I have had to make some ‘guesstimates’ about some data.
Wing span and area: 65′ 6″. 551 square feet. Length: 51′ 5″.
Empty weight: I found a wide range of figures which depend on the fit of armour plate, fuel tank installation, machine-gun options etc. Official US Navy figures for their PV-1s varied from just under 19,000 lbs to about 20,000 lbs. I believe that 20,000 lbs would be pretty right for our RNZAF aircraft.
Maximum weight: Again the figures varied from about 26,500 lbs for the earlier RAF models to 31,000 lbs. Other figures were 32,000 lbs for the Lexington and also 34,000 lbs but I am sure that was an overload figure for very long ferry flights when drop-tanks and a bomb-bay fuel tank was installed.
Service ceiling: US Navy documents state 22,000 feet.
Initial rate of climb: 2,000 fpm. Time to climb to 10,000 feet 9 minutes; to 20,000 feet 25 minutes.
Range: With standard tanks 1,450 nautical miles. With ferry tanks 2,250 nm.
Stalling speeds with zero flap and at idle power: 86 knots IAS at 31,000 lbs; reducing progressively to 77 knots with minimum fuel and no bomb load. At near maximum weight, this would result in a best rate of climb speed of about 140 knots IAS and a best range IAS of 160 – 170 knots.
The RAF notes say 140 mph (122 knots) to 12,000 feet but that is for a take-off weight of only 26,500 lbs. Climbing higher than 12,000 feet the IAS should be reduced by just under 2 knots per thousand feet. In reality, a faster cruise-climb airspeed would have been used unless perhaps you were a US Marine Corps pilot flying a night-fighter Ventura variant which saw some service in the Pacific theatre.
TO BE CONTINUED IN PART TWO: This contains details about the handling qualities of the Ventura, including excerpts from “Pilot’s Notes.†It took me a hell of a long time to research so, naturally, I believe it will prove of interest to many readers (he says modestly).
Anyway troops, “straighten up and fly right!†as the WWII song would have it.
Cheers from, on June 5th, 2012.
mikefeeney@actrix.co.nz
Home & Cell phone numbers supplied on the web site
"Wings of Time" # 12. Part One.
The Lockheed-Vega PV-1 Ventura/B-34 Lexington and PV-2 Harpoon.
Should you prefer, you may like to click on the Link below to read this on my archive section. The images are somewhat larger. There is stuff here going back to 2009.
www.aerohub.co.nz/category/chronicles/
or
www.aerohub.co.nz/2012/06/wings-of-time-12-part-one/
A review by Mike Feeney with the emphasis being placed on the technical, operational and handling aspects of this controversial patrol bomber.
New Zealand has a long history of operating Lockheed aeroplanes from the 1930s up until the present. There have been the L-10 Electra, the smaller L-12 Electra Junior, L-14 Super Electra/ Hudson, L-18 Lodestar, PV-1 Ventura, L-188 Electra and, currently, the C-130 Hercules and P-3 Orion.
The Ventura was, until the Canberra, the RNZAF’s heaviest and most powerful bomber type. It has been maligned by some, in my opinion unfairly. The high losses incurred by 487 (NZ) Squadron during their daylight raids on targets in Holland were due to operational factors with respect to escorting Spitfires becoming entangled with Bf109s at higher levels and far from the Venturas which they were supposed to be protecting. Most of the 487 aircraft were shot down before reaching the target power stations and the recall radio message was either not heard or was ignored.
But regardless of the causal factors for the ghastly losses, no type, with the possible exception of the DH Mosquito, could have survived concentrated defence by fighters such as the Bf109 and Fw190. The result would have been the same had the aircraft used been the B-25 Mitchell, A-20 Havoc/Boston or Martin B-26 Marauder. At full power a clean Ventura, at 280 knots true airspeed (TAS) (225 knots indicated airspeed) at 15,000 feet was actually somewhat faster than all of those types.They all cruised at a similar TAS, depending on the phase of the mission profile; 160 – 200 knots TAS. The maximum level TAS figures vary with different variants but, with respect to vulnerability to AA fire and attack by fighter aircraft, are of no significance. It mattered not to the pilot of a Fw190 or Bf109 if an Allied aircraft was trying to escape at 250 or 280 knots. The max. diving speed (Vne) IAS for a clean PV-1 is 375 mph (325 knots).
NOTE TO THE PHOTOGRAPH BELOW: I found this faded photograph which I believe to be of RNZAF NCOs who were with No. 487 (NZ) Squadron in early 1943 at RAF Station Methold. I don’t know who took it and I have no names of the chaps. Perhaps a reader will recognise a familiar face?
In the operational area of the RNZAF Venturas, their principal fighter threat came from the Nakajima Ki-43 ‘Oscar’ or the Mitsubishi A6M Zero/Zeke, which were based at the Rabaul airstrip and some other nearby strips in East New Britain. By the time RNZAF Venturas were moved to the main Piva airfield on Bougainville in 1944 the number of Japanese fighters was much reduced due to the intense bombing and strafing raids on the Japanese airfields. The USAAF and US Marine Corps units were moving west, leaving the small RNZAF forces to help ‘mop up’ the remaining isolated enemy ground troops. The extremely agile Ki-43 had two 12.7mm machine-guns mounted on the upper fuselage so posed a threat to the Ventura…if it had an altitude advantage as the Oscar’s maximum level speed was only 280 knots. The Mitsubishi A6M Zero was marginally faster at 290 knots. A clean, light Ventura, at max. power, particularly if it had altitude to trade, could almost outrun an Oscar or Zero and if Japanese pilots decided to pursue from astern at a slow closing rate, they became very vulnerable to either the Ventura’s upper or belly guns.
Notes to the map below: To put some sort of scale to this simplified map, I think the distance from Port Moresby to Bougainville is about 550 nautical miles; from memory about 2.5 hours in a Fokker F-27 or 4.0 hours in a DC-3. The little island group directly nor-west of Bougainville is where the Green Island WWII airfield was. Directly west of there is Rabaul; the Japanese HQ. The longitude of the sou-east end of Bougainville is 156 East and the border between the PNG mainland and the Indonesian held West Papua runs down 141 East which makes the length of PNG about 900 nautical miles. The Equator is a little north of the Admiralty Islands. The main aerodrome is on Manus island which was a large US base during WWII. It was there that a huge fleet of US ships assembled in preparation for the invasion of the Philippines. And of course it was during the Battle of the Bismarck Sea that USAAF and RAAF aircraft destroyed the large Japanese supply convoy. A particularly historic region indeed.
The RNZAF operated 82 PV-1s, 57 B-34s and inherited 4 PV-2 Harpoons later in the war. They were flown by Squadron No.s 1, 2, 3, 4, 8, 9 and No.1 Operational Training Unit. Their operational theatre was almost entirely in the South-West Pacific from Guadalcanal to Bougainville and Green Island which is between Bougainville and the Japanese base at Rabaul, at the eastern end of New Britain, New Guinea. The RNZAF had also received 94 Lend-lease Hudsons and 4 Lodestars.
Some 40 RNZAF Venturas were destroyed or written-off as beyond repair or broken down to spares due to enemy action, training accidents or non-combat accidents in the field; mainly take-off or landing mishaps.
Notes to the map below: The island called Nissan is also known as Green Island. The Piva airfields where RNZAF aircraft were based were on the coastal flats near Torokina. Just a few miles from Buin is where Admiral Yamamoto’s Betty bomber was intercepted and shot down by Lockheed P-38s from Henderson Field, Gaudalcanal. The last time I was around the area, Mount Bagana was fairly active. I really enjoyed being based at Rabaul and came to know the region well. Buka and Kieta were the main airstrips but there were others which could take a DC-3 such as Buin and Wakunai. Extensive coconut plantations covered much of the coastal areas of all islands. The huge copper mine was inland from Kieta.
The Ventura programme was initiated in conjunction with the British who asked Lockheed for an upgraded version of the Hudson, which the RAF were already using in the maritime patrol role.. The Vega division of Lockheed used the L-18 Lodestar as the basis for the redesign. The Lodestar was simply a stretched-fuselage version of the L-14 ‘Super Electra’/Hudson. Other than the lengthened fuselage to permit two more seat rows, it was virtually identical to the L-14. The Model 237-27-01 first flew on 31st July, 1941 with deliveries to the RAF commencing in September 1941. Other British Commonwealth air forces also used them such as Canada, Australia and South Africa and the US Navy and USAAF operated many in different variants. The PV-1 and the later PV-2 also found their way to a large number of other countries.
Before considering the Ventura’s handling reputation, it is important to understand some details of the type. First its wing and flaps as they are the key factors involved.
The Ventura’s highly tapered wing spans 65′ 6″ and has a zero-flap area of just 551 square feet. When the huge Fowler flaps are fully extended the area increases to 619 square feet. In order to enhance aileron authority at low airspeed, and when on one engine, three leading-edge slots are integral in each outer wing.
The single mainspar runs through the fuselage while the front and rear spars are attached to the fuselage. There are four fuel tanks in the centre-section plus one in each wing outboard of the engines. Their capacities are (Ventura I and II): Front mains 94 Imp. gallons per side. Rear mains 107 Imp. gallons per side. Auxillaries (outer wing) 34 Imp. gallons per side. Total for standard wing tank fit 470 Imp. gallons. Fuel jettison valves were fitted to the left front, left rear and right front tanks.Two fuselage tanks could also be fitted. Under-wing drop-tanks could replace the bombs.
The main undercarriage retracts rearwards and the tailwheel retracts. The gear, brakes, bomb-bay doors and the Sperry autopilot are hydraulically actuated as are the flaps via a system of cables which move the flaps along their tracks.
To put the wing into perspective, it is 30 feet shorter than that of a DC-3 and its area is 400 square feet less. As Venturas operated at similar weights to the military C-47, the wing loading, at 55 lbs/sq. ft. was about double that of the C-47.
The Lodestar fuselage was widened and deepened in order to fit a bomb-bay which could accept 3,000 lbs of bombs, or 6 x 325 lb depth-charges or a torpedo. Extra bomb-bay fuel tanks could also be installed for very long ferry/patrol flights. A ventral gun position with 2 x 0.303 machine-guns was fitted. The upper powered turret had 2 x 0.303s also. The initial nose section had side windows and a flat lower window for a bomb-aimer and sight. 2 x 0.303s were located in a flexible mount. Later variants had a ‘solid’ nose to allow a battery of 0.50 machine-guns to be fitted. Other models had the 0.303″ guns replaced with 0.50″ machine-guns.
The tailplane and fin/rudder assembly remained as per the Lodestar which meant an increase in the minimum control speed in the air (Vmca), as compared to the Lodestar or Hudson with their 1,200 bhp R-1820 Wright Cyclones. More on handling later.
The basic specifications of the PV-1/B-34 models used by the RNZAF follow. Bear in mind that variations in areas such as weights occurred in the field and in the literature so I have had to make some ‘guesstimates’ about some data.
Wing span and area: 65′ 6″. 551 square feet. Length: 51′ 5″.
Empty weight: I found a wide range of figures which depend on the fit of armour plate, fuel tank installation, machine-gun options etc. Official US Navy figures for their PV-1s varied from just under 19,000 lbs to about 20,000 lbs. I believe that 20,000 lbs would be pretty right for our RNZAF aircraft.
Maximum weight: Again the figures varied from about 26,500 lbs for the earlier RAF models to 31,000 lbs. Other figures were 32,000 lbs for the Lexington and also 34,000 lbs but I am sure that was an overload figure for very long ferry flights when drop-tanks and a bomb-bay fuel tank was installed.
Service ceiling: US Navy documents state 22,000 feet.
Initial rate of climb: 2,000 fpm. Time to climb to 10,000 feet 9 minutes; to 20,000 feet 25 minutes.
Range: With standard tanks 1,450 nautical miles. With ferry tanks 2,250 nm.
Stalling speeds with zero flap and at idle power: 86 knots IAS at 31,000 lbs; reducing progressively to 77 knots with minimum fuel and no bomb load. At near maximum weight, this would result in a best rate of climb speed of about 140 knots IAS and a best range IAS of 160 – 170 knots.
The RAF notes say 140 mph (122 knots) to 12,000 feet but that is for a take-off weight of only 26,500 lbs. Climbing higher than 12,000 feet the IAS should be reduced by just under 2 knots per thousand feet. In reality, a faster cruise-climb airspeed would have been used unless perhaps you were a US Marine Corps pilot flying a night-fighter Ventura variant which saw some service in the Pacific theatre.
TO BE CONTINUED IN PART TWO: This contains details about the handling qualities of the Ventura, including excerpts from “Pilot’s Notes.†It took me a hell of a long time to research so, naturally, I believe it will prove of interest to many readers (he says modestly).
Anyway troops, “straighten up and fly right!†as the WWII song would have it.
Cheers from, on June 5th, 2012.
mikefeeney@actrix.co.nz
Home & Cell phone numbers supplied on the web site
