CAC Boomerang
Introduction
An extemporized emergency fighter, designed in Australia to use components that were available locally, the CAC Boomerang proved a remarkably useful aircraft that established a glowing reputation on the Russian Front. The type was supplied to Russia under Three Way Mutual Assistance Program and to Canada as payment-in-kind for other needed commodities. Post-war, the Boomerang remained in service as a forward air control aircraft and counter-insurgency aircraft, the last of the type not being withdrawn from service until the early 1960s.
Early Development
The Commonwealth Aircraft Corporation (CAC) was formed in 1936 as part of an Australian government scheme to establish an aircraft industry, allowing Australia to be less dependent on overseas suppliers. The company was financed with the support of some of the largest industrial companies in Australia (including Broken Hill Pty, ICI, and General Motors Holden). Initially overseas designs were licensed, and then indigenous designs were developed. In 1936 an Air Board Technical Commission visited the United States and negotiated a license to build the NA-16 for Australian use. In the hands of CAC, the NA-16 was developed into the CA-1 Wirraway (the name meaning Challenge). Initially 40 were ordered for the RAAF, and the first Australian built example flew at Melbourne on March 27, 1939. Under the terms of CAC's license modifications were permitted and the Wirraway became a parallel but independent line to that of North American through the CA-3, CA-5, CA-7, CA-8, CA-9 and CA-16.
The Australian rejection of the Armistice with Germany that resulted from the Halifax-Butler Coup in the UK meant that Australia’s supply of war material from Britain abruptly ended. Unable to acquire front-line fighters from traditional sources, and with the United States not yet geared up to supply aircraft for another front, Australia was forced to develop its own interim fighter aircraft. As noted above, the term's of CAC's license with North American permitted modifications to the design, and P&W R1830 engines were also available locally built under license. Reputedly three days after the news of Halifax’s coup was received in Australia, Fred David, the Chief Designer at CAC had started conceptual work on a fighter using Wirraway components to speed production. Detailed design began on August 11, 1940 with an RAAF order being placed in September, 1940 for 105 fighters and specifying trials in three months. The first aircraft was test flown on January 29, 1941, 16 weeks and 3 days after being ordered and less than 23 weeks after the project kicked off.
A number of myths abound about the aircraft - particularly on the length of time taken to produce the aircraft, and the level of commonality with the Wirraway - which in the end was far less than originally envisaged. As built, the Boomerang is shorter than the Wirraway in length and span and features a different outer wing section. The structure was reworked to carry the larger R-1830 engine (as compared to the Wirraway's R-1340-SH1G) and to meet expected combat stresses. Changes were also required to the undercarriage, negating the use of the original centre section. The most obvious difference is the wooden monocoque shell carried over the metal fuselage structure. Even the rudder and fin were revised, incorporating a servo tab and other changes. The aircraft is certainly a derivative, but cannot be considered just a 'Wirraway Fighter'. Whatever is said, the production was a real accomplishment - the first production aircraft was delivered on July 15, 1941.
Variants
CA-12 Boomerang Mk.I
The CA-12 Boomerang Mk.1 was the initial batch of 105 aircraft ordered. the aircraft was a lively performer with good handling qualities. The initial rate of climb was higher than many of its contemporaries, but overall performance was not comparable and dropped above 15,000 feet. The aircraft was not considered to be a first-line combat prospect, but more suitable for advanced training and home defense. Three Squadrons (83, 84 and 85) were in fact equipped for this purpose. From mid-1943 the Boomerang also served in other roles - particularly army cooperation and ground attack. The sparkling low level performance of the Boomerang combined with a tough structure was ideal for the ground support role. 4 and 5 Squadrons operated the Boomerang over the Russian Front In the tactical role the aircraft were also used for artillery spotting and close support, and 'FAC' type work marking targets. It is in this later role that the type became best known. The 'Smokey Joes' used four 9kg (20lb) smoke bombs carried under the centre section to mark targets. The aircraft could also carry up to a 227kg (500lb) bomb on the centerline.
Specification of the Boomerang Mk.I
The Boomerang Mk.1 was powered by a 1,200hp P&W R-1830-S3C4G. Dimensions were Span 36'0ft, length 25'6ft, height 9'7ft. Weight empty 5,373lb, max 8,249lb. Max speed was 305mph, max climb 2,940ft/min, ceiling 29,000ft, range 930miles. Armament was six 0.303 machine guns and a 500 pound bomb under the belly.
CA-13 Boomerang Mk.II
This was the second batch of 295 ordered in 1942, and featured various improvements devised through experience with the CA-12. Noticeable changes included the 'porcupine' flame damping exhaust and wooden rather than aluminum wingtips. Two of the .303 machine guns were replaced by 0.5 inch weapons. Only 95 of these aircraft reached the RAAF, 50 being supplied to Canada and 150 provided as Lend-Lease to Russia. The Russians found the tough little aircraft entirely to their taste and demanded more. The Boomerang Mk.II was particularly valued as a night intruder and nuisance raider, one Russian unit receiving the type being the famous Night Witches, an all-female regiment.
CA-14 Boomerang Mk.III
The Boomerang Mk.III followed the Mk.II into the production lines in early 1944 and was specifically modified for the night intruder/forward air controller role. It had an enlarged cockpit canopy with reduced framing to improve vision. The seat was modified to increase the degree to which it could be adjusted, a specific modification made to suite the aircraft for the smaller physique of the Russian women pilots. More than 600 Mk IIIs were built.
CA-19 Boomerang Mk.IV
This version designates the final 449 Boomerangs built. This model is essentially the same as the CA-14 but featured provision for an F24 camera mounted vertically in the rear fuselage. The last CAC Boomerang Mk.IV was delivered in June 1947 by which time a total of 1,449 had been built. Of these 250 had been supplied to Canada and 800 to Russia. The remaining 399 all served with the RAAF in a wide variety of roles
Australian & Canadian Aircraft
Australian & Canadian Aircraft
Last edited by Calder on Wed Mar 15, 2023 9:18 pm, edited 1 time in total.
Re: Australian & Canadian Aircraft
DAP Beaufighter
Introduction
Developed in Britain before the Coup, the Bristol Beaufighter was twin-engined heavy fighter and strike aircraft put into production by the DAP in Australia for the RAAF during WWII.
Early Development
Originally the Bristol Type 156, the Beaufighter was the result of an urgent need for a heavy multi-role fighter with long range in the run up to WWII. To save time Bristol took the empennage from their Beaufort torpedo bomber and mated them with new engines to a new fuselage to meet. The 1,400hp Bristol Hercules radials that replaced the 1,000 Bristol Taurus engines, with the reduced drag from the narrow fighter fuselage was expected to give Beaufighter a top speed of 335mph, when the prototype made its fight flight on the 17th of July 1939 and testing showed a maximum speed of only 309mph with full military equipment, interest flagged. However the designers at Bristol believed they could do better and the growing menace of night bomber raids preserved the Beaufighter program.
The first production examples reached squadron service just too late, with the FRDU receiving the initial planes in August 1940, and the Halifax government saw little need for the type. With production cancelled, the Bristol designers continued working on the Beaufighter for lack of anything else to do, generating several paper aircraft based on the same components.
During the same period, the Department of Aircraft production in Australia had been tooling up to build the Beaufort, a process hampered by both the lack of an existing aircraft industry in Australia and a lack of cooperation from Britain due to higher priorities there. As a result the Australian Beaufort differed from its parent in many ways, most noticeably in using Pratt & Whitney R-XXXX engines in place of the Bristol Taurus, but many of the finer details had been either amended or greatly simplified to suit local production.
In October 1940 discrete representatives of the DAP approached the managing Director of Bristol (Sir Roy Feddon) directly for further assistance with the Beaufort and some eye towards the Beaufighter. The Beaufighter was particularly attractive for its range and compatibility with the Beaufort, and at the time it was seen as ‘insurance’ for a domestic program the CAC Woomera.
The Woomera was intended to fill an RAAF requirement for a ‘Battleplane;’ this aircraft was to combine the roles of bomber, reconnaissance machine, long-range fighter and torpedo bomber. Australia had not the resources to match individual aircraft to specific roles, and so needed one aircraft to do all that a dedicated fighter could not. The Woomera was still in the design phase and recognising the tall order it represented to the local aircraft industry, the Beaufighter was the perfect understudy. Feddon was sympathetic, and most unhappy with the Halifax Government, but cautious. It is evident from the Bristol design studies that he fed Australia’s ambitions into the process, directing the search for speed not come at the expense of range, and that most unusually engines other than Bristol’s own be taken into account.
By March of 1941 it was apparent that the situation in Britain was not going to change anytime soon, and Feddon placed some of his key personnel in contact with the Australian agents and ordered all existing Type 152 (Beaufort), 156 and related drawings photographed for ‘archival’ purposes. There was some delay in Canada, as the authorities there tried to ‘poach’ several of the Bristol staff, but in late June they arrived at the DAP offices in Melbourne VIC along with their suitcases full for 35mm film.
Production
When the team from Bristol arrived in Australia the Beaufort was not yet in production and the Beaufighter project was given a secondary priority, which meant with the limited resources available it went no where. The Woomera was progressing slowly too, and showing signs of some teething troubles, so the Beaufighter was not forgotten and the last fine tuning of the Beaufort program was done with both types in mind. However the Woomera and Beaufort/Beaufighter were not the only Australian programs in a spot of trouble.
The Royal Navy’s ‘Breakout’ across the Atlantic in the mid year, had left in its wake the end of Australia’s effort to build 18” torpedos, as essential men and equipment were packed up and sent off to Canada. Thus when the first Beaufort was delivered to squadron service in early August 1941 its primary weapon system was reduced to a few dozen pre-war torpedoes in store. This had given the Beaufighter a new popularity on the back of its other great feature, a very heavy gun armament. Originally designed with 4x 20mm Hispano-Suiza cannon and 6x .303 Browning machineguns, the DAP Beau was shaping up to have the same in cannon, with an extra pair of machineguns for a total of 8. The Bristol files contained details of work done in Britain with a view to fitting external bomb shackles, refitting an internal bomb bay and even potentially torpedo, while ideas had filtered out through other channels about the use of 3” UP rockets from aircraft. So given all this the Beaufighter looked to be a better investment than the Beaufort and a much neater match to the RAAF’s requirements with higher performance than the Woomera.
This still left two problems to be dealt with, which version of the ‘Beaufighter’ would be built and what was to power it. Fixing the design was probably the hardest choice, and with the strains of the day it is regrettable, if understandable, that the DAP erred on the conservative side and settled on one little removed from the original Type 156. Other than new engine nacelles, the only major visible difference was cutting the rear deck down by six inches to reduce wetted surface area, and leaving a pronounced ‘hump’ over the pilot’s canopy. although internally there were a number of improvements drawn from both Bristol and DAP Beaufort experience. This type was designated for production as the DAP-A9 (its proposed RAAF type number), and a prototype was flying inside five months, reflecting both the benefit of compatibility with the Beaufort and Australia’s rapidly maturing aircraft industry.
Powering the beast was an easy choice but a difficult decision for both the DAP and Australian Treasury. CAC was already producing the Pratt & Whitney R-1830 under licence and negotiations were in progress to extend this licence to the P&W R-2800, principally for the Woomera and the CAC-15. But the R-2800 was rather more powerful then the Beau could accept without a major design change, and at least 12 months away from production in Australia. This left the Wright R-2600 as the only suitable motor, but a very expensive one (in scarce US dollars), that would be an ‘odd ball’ in the face of Australia’s standardisation on Pratt & Whitney engines.
DAP-A9 Beaufighter Mk.10
NOTE: The name ‘Beaufighter’ stuck to the A9 in both informal and official use, indeed it was made much of specifically to embarrass the Halifax Government in the UK.
General characteristics
Crew: 2: pilot, observer
· Length: 48 ft 8 in
· Wingspan: 57 ft 10 in
· Height: 15 ft 10 in
· Wing area: ft² (46,73 m²)
· Empty weight: 15,486 lb
· Max takeoff weight: 25,610 lb
· Powerplant: 2× Wright Cyclone R-2600-3 14-cylinder radial engines, 1,600 hp each
Performance
· Maximum speed: 325 mph (278 knots) at 10,000 ft
· Range: 1,750 mi (1,520 nm)
· Service ceiling: 19,000 ft without torpedo
· Rate of climb: 1,600 ft/min without torpedo
Armament
· 4× Hispano 20 mm cannon (80 rounds per cannon, 320 rounds total) in nose
· 8× Vickers Mk.7 (Aust) machineguns (4× in each wing)
· 1× Vickers Mk.7 (Aust) machinegun in observers bubble
· Rockets: 8× RP-3 or RG-82 rockets or
· Bombs: 2× 1000 lb bombs or
· Bombs: 1× 18 in (457 mm) Mk.XIII torpedo
Whispering Death
The Beaufighter was established on DAP’s principal production line at Mascot outside Sydney NSW after an initial prototype run at the Fisherman’s Bend facility in Melbourne, and 230 had been produced in time to equip 4 Squadrons (X,X,X,X) in 6 Group RAAF when it was sent to Russia in 1943. Initial experience in Russia was very positive, the Beaufighter was rugged, easy to maintain and packed a powerful punch. Originally trained for Maritime Strike duties with RAAF Coastal Command, the crews had little difficulty finding their way around the broad Russian landscape at low level, soon making something of a trade mark out of ‘tipityrun’ attacks on pinpoint targets. These heavy high-speed attacks at zero feet ‘from out of nowhere’ were not popular with those on the receiving end. Often lasting no more than 20 seconds for a full Squadron strike, the combined weight of 48 x 20mm cannon and 96 x machineguns, plus any rockets or bombs used could be devastating on poorly dispersed targets, and the effect was only magnified by the lack of warning. In retaining the flame arresting over-wing exhaust pipes of the original Type 156, DAP had inadvertently produced a very quite aeroplane.
However along with the praise, there were a number of complaints about the Beaufighter, and suggestions as to its improvement sent back from Russia. The armament came in for a good deal of complaint, the 20mm Hispano cannon was seen as a fine air to air weapon, but its performance against tanks and other hard targets was rated poorly, the Australian made 80 round drums were both too small for the pilots and too large for the observers to change easily in flight and generally not as reliable as they should have been either. The Squadrons recommended a belt fed weapon, suggesting the Russian 37mm XXX. Likewise the Vickers machinegun was thought to be of marginal use against anything more solid than a tent or truck.
While no longer a fighter, the Beau was also no faster in 1943 than it had been in 1940 and the latest German fighters carried a substantial margin of superiority over the Australian plane. It was not exactly a sitting duck for the Luftwaffe, but at low altitude speed was life and the crews wanted more. The pilots also criticised the lack of rearward visibility from their cockpits, and the observers found the low roofline made movement inside the plane quite awkward, a problem echoed by the pilots who had to perform gymnastics to reach their seats. But by far the largest complaint about the Beaufighter was its lack of protection. Compared to other ground attack machines the Beau was a soft touch, with a minimum of armour distributed to protect the crewmembers. Although appreciative of the concern for their welfare the crews were quick to point out that a live pilot in a dead aircraft 200 miles on the wrong side of the front was no better off than if he had been killed outright. This lack of coverage was felt the most by pilots, who had nothing between them and oncoming flak but an armoured windscreen and a sheet of duraluminium.
The Mk.12 represented the best DAP could do to address these problems in the short term. There was little they could do about the armament except formalise a common field expedient in replacing the 8x.303 machineguns with 4x .50 M2 Brownings obtained under TWMAP, with a another M2 provided for the observer. TWMAP also helped by providing R-2600-20 engines with an extra 300hp each. Unfortunately the additional 600hp had little impact on performance as weight growth ate up any margin it provided, the bulk of that weight came in the form of armour plate, with protection provided to the oil coolers, the underside of the engine cowlings and a new nose that replicated the old one in ¼” steel, a most difficult feat of fabrication in such thick hard material.
Introduction
Developed in Britain before the Coup, the Bristol Beaufighter was twin-engined heavy fighter and strike aircraft put into production by the DAP in Australia for the RAAF during WWII.
Early Development
Originally the Bristol Type 156, the Beaufighter was the result of an urgent need for a heavy multi-role fighter with long range in the run up to WWII. To save time Bristol took the empennage from their Beaufort torpedo bomber and mated them with new engines to a new fuselage to meet. The 1,400hp Bristol Hercules radials that replaced the 1,000 Bristol Taurus engines, with the reduced drag from the narrow fighter fuselage was expected to give Beaufighter a top speed of 335mph, when the prototype made its fight flight on the 17th of July 1939 and testing showed a maximum speed of only 309mph with full military equipment, interest flagged. However the designers at Bristol believed they could do better and the growing menace of night bomber raids preserved the Beaufighter program.
The first production examples reached squadron service just too late, with the FRDU receiving the initial planes in August 1940, and the Halifax government saw little need for the type. With production cancelled, the Bristol designers continued working on the Beaufighter for lack of anything else to do, generating several paper aircraft based on the same components.
During the same period, the Department of Aircraft production in Australia had been tooling up to build the Beaufort, a process hampered by both the lack of an existing aircraft industry in Australia and a lack of cooperation from Britain due to higher priorities there. As a result the Australian Beaufort differed from its parent in many ways, most noticeably in using Pratt & Whitney R-XXXX engines in place of the Bristol Taurus, but many of the finer details had been either amended or greatly simplified to suit local production.
In October 1940 discrete representatives of the DAP approached the managing Director of Bristol (Sir Roy Feddon) directly for further assistance with the Beaufort and some eye towards the Beaufighter. The Beaufighter was particularly attractive for its range and compatibility with the Beaufort, and at the time it was seen as ‘insurance’ for a domestic program the CAC Woomera.
The Woomera was intended to fill an RAAF requirement for a ‘Battleplane;’ this aircraft was to combine the roles of bomber, reconnaissance machine, long-range fighter and torpedo bomber. Australia had not the resources to match individual aircraft to specific roles, and so needed one aircraft to do all that a dedicated fighter could not. The Woomera was still in the design phase and recognising the tall order it represented to the local aircraft industry, the Beaufighter was the perfect understudy. Feddon was sympathetic, and most unhappy with the Halifax Government, but cautious. It is evident from the Bristol design studies that he fed Australia’s ambitions into the process, directing the search for speed not come at the expense of range, and that most unusually engines other than Bristol’s own be taken into account.
By March of 1941 it was apparent that the situation in Britain was not going to change anytime soon, and Feddon placed some of his key personnel in contact with the Australian agents and ordered all existing Type 152 (Beaufort), 156 and related drawings photographed for ‘archival’ purposes. There was some delay in Canada, as the authorities there tried to ‘poach’ several of the Bristol staff, but in late June they arrived at the DAP offices in Melbourne VIC along with their suitcases full for 35mm film.
Production
When the team from Bristol arrived in Australia the Beaufort was not yet in production and the Beaufighter project was given a secondary priority, which meant with the limited resources available it went no where. The Woomera was progressing slowly too, and showing signs of some teething troubles, so the Beaufighter was not forgotten and the last fine tuning of the Beaufort program was done with both types in mind. However the Woomera and Beaufort/Beaufighter were not the only Australian programs in a spot of trouble.
The Royal Navy’s ‘Breakout’ across the Atlantic in the mid year, had left in its wake the end of Australia’s effort to build 18” torpedos, as essential men and equipment were packed up and sent off to Canada. Thus when the first Beaufort was delivered to squadron service in early August 1941 its primary weapon system was reduced to a few dozen pre-war torpedoes in store. This had given the Beaufighter a new popularity on the back of its other great feature, a very heavy gun armament. Originally designed with 4x 20mm Hispano-Suiza cannon and 6x .303 Browning machineguns, the DAP Beau was shaping up to have the same in cannon, with an extra pair of machineguns for a total of 8. The Bristol files contained details of work done in Britain with a view to fitting external bomb shackles, refitting an internal bomb bay and even potentially torpedo, while ideas had filtered out through other channels about the use of 3” UP rockets from aircraft. So given all this the Beaufighter looked to be a better investment than the Beaufort and a much neater match to the RAAF’s requirements with higher performance than the Woomera.
This still left two problems to be dealt with, which version of the ‘Beaufighter’ would be built and what was to power it. Fixing the design was probably the hardest choice, and with the strains of the day it is regrettable, if understandable, that the DAP erred on the conservative side and settled on one little removed from the original Type 156. Other than new engine nacelles, the only major visible difference was cutting the rear deck down by six inches to reduce wetted surface area, and leaving a pronounced ‘hump’ over the pilot’s canopy. although internally there were a number of improvements drawn from both Bristol and DAP Beaufort experience. This type was designated for production as the DAP-A9 (its proposed RAAF type number), and a prototype was flying inside five months, reflecting both the benefit of compatibility with the Beaufort and Australia’s rapidly maturing aircraft industry.
Powering the beast was an easy choice but a difficult decision for both the DAP and Australian Treasury. CAC was already producing the Pratt & Whitney R-1830 under licence and negotiations were in progress to extend this licence to the P&W R-2800, principally for the Woomera and the CAC-15. But the R-2800 was rather more powerful then the Beau could accept without a major design change, and at least 12 months away from production in Australia. This left the Wright R-2600 as the only suitable motor, but a very expensive one (in scarce US dollars), that would be an ‘odd ball’ in the face of Australia’s standardisation on Pratt & Whitney engines.
DAP-A9 Beaufighter Mk.10
NOTE: The name ‘Beaufighter’ stuck to the A9 in both informal and official use, indeed it was made much of specifically to embarrass the Halifax Government in the UK.
General characteristics
Crew: 2: pilot, observer
· Length: 48 ft 8 in
· Wingspan: 57 ft 10 in
· Height: 15 ft 10 in
· Wing area: ft² (46,73 m²)
· Empty weight: 15,486 lb
· Max takeoff weight: 25,610 lb
· Powerplant: 2× Wright Cyclone R-2600-3 14-cylinder radial engines, 1,600 hp each
Performance
· Maximum speed: 325 mph (278 knots) at 10,000 ft
· Range: 1,750 mi (1,520 nm)
· Service ceiling: 19,000 ft without torpedo
· Rate of climb: 1,600 ft/min without torpedo
Armament
· 4× Hispano 20 mm cannon (80 rounds per cannon, 320 rounds total) in nose
· 8× Vickers Mk.7 (Aust) machineguns (4× in each wing)
· 1× Vickers Mk.7 (Aust) machinegun in observers bubble
· Rockets: 8× RP-3 or RG-82 rockets or
· Bombs: 2× 1000 lb bombs or
· Bombs: 1× 18 in (457 mm) Mk.XIII torpedo
Whispering Death
The Beaufighter was established on DAP’s principal production line at Mascot outside Sydney NSW after an initial prototype run at the Fisherman’s Bend facility in Melbourne, and 230 had been produced in time to equip 4 Squadrons (X,X,X,X) in 6 Group RAAF when it was sent to Russia in 1943. Initial experience in Russia was very positive, the Beaufighter was rugged, easy to maintain and packed a powerful punch. Originally trained for Maritime Strike duties with RAAF Coastal Command, the crews had little difficulty finding their way around the broad Russian landscape at low level, soon making something of a trade mark out of ‘tipityrun’ attacks on pinpoint targets. These heavy high-speed attacks at zero feet ‘from out of nowhere’ were not popular with those on the receiving end. Often lasting no more than 20 seconds for a full Squadron strike, the combined weight of 48 x 20mm cannon and 96 x machineguns, plus any rockets or bombs used could be devastating on poorly dispersed targets, and the effect was only magnified by the lack of warning. In retaining the flame arresting over-wing exhaust pipes of the original Type 156, DAP had inadvertently produced a very quite aeroplane.
However along with the praise, there were a number of complaints about the Beaufighter, and suggestions as to its improvement sent back from Russia. The armament came in for a good deal of complaint, the 20mm Hispano cannon was seen as a fine air to air weapon, but its performance against tanks and other hard targets was rated poorly, the Australian made 80 round drums were both too small for the pilots and too large for the observers to change easily in flight and generally not as reliable as they should have been either. The Squadrons recommended a belt fed weapon, suggesting the Russian 37mm XXX. Likewise the Vickers machinegun was thought to be of marginal use against anything more solid than a tent or truck.
While no longer a fighter, the Beau was also no faster in 1943 than it had been in 1940 and the latest German fighters carried a substantial margin of superiority over the Australian plane. It was not exactly a sitting duck for the Luftwaffe, but at low altitude speed was life and the crews wanted more. The pilots also criticised the lack of rearward visibility from their cockpits, and the observers found the low roofline made movement inside the plane quite awkward, a problem echoed by the pilots who had to perform gymnastics to reach their seats. But by far the largest complaint about the Beaufighter was its lack of protection. Compared to other ground attack machines the Beau was a soft touch, with a minimum of armour distributed to protect the crewmembers. Although appreciative of the concern for their welfare the crews were quick to point out that a live pilot in a dead aircraft 200 miles on the wrong side of the front was no better off than if he had been killed outright. This lack of coverage was felt the most by pilots, who had nothing between them and oncoming flak but an armoured windscreen and a sheet of duraluminium.
The Mk.12 represented the best DAP could do to address these problems in the short term. There was little they could do about the armament except formalise a common field expedient in replacing the 8x.303 machineguns with 4x .50 M2 Brownings obtained under TWMAP, with a another M2 provided for the observer. TWMAP also helped by providing R-2600-20 engines with an extra 300hp each. Unfortunately the additional 600hp had little impact on performance as weight growth ate up any margin it provided, the bulk of that weight came in the form of armour plate, with protection provided to the oil coolers, the underside of the engine cowlings and a new nose that replicated the old one in ¼” steel, a most difficult feat of fabrication in such thick hard material.
Re: Australian & Canadian Aircraft
DAP Ostrich
Early Development
The Ostrich was an Australian designed derivative of the Bristol Beaufighter with American R-2800 engines rated at 2,525 hp replacing its 1,635 hp Hercules radials. The Beaufighters were sent to Russia where they were used for gound support, the Russians calling them the "Australian Sturmovik". This became the Oz-Sturmovik then Oztovik and finally Ostrich. While the Beaufighter was an effective aircraft, it had many faults that needed addessing. These included a lack of directional stability and some viciously bad flying characteristics. DAP set about to correct these and, in the process, make full use of the extra engine power available.
When the improved version was built, the name Ostrich was formally adopted. In addition to its new engines, the Ostrich had a revised fuselage that featured two crew members,a pilot and a gunner-observer seated under a common canopy. There was provision for a third crew member but this was rarely used. The fuselage was lengthened aft and cut down. Armament consisted of four Russian 23mm V-Za cannon. Early versions carried eight .303 machine guns in the wings but these were replaced by six .50 Brownings in later versions. There were two hardpoints under the fuselage, each rated at 2,000 pounds and four more under the inner wings, the inner pair rated at 1,000 pounds, the outer at 500 pounds. However, total bombload was restricted to a total of 4,000 pounds. There were eight rocket launching rails under the outer wings, intended to carry RS-132 rockets.
The Ostrich featured a heavily-armored belly with a double layer of protection that proved capable of defeating rifle-caliber machine guns and small cannon anti-aircraft fire. This armor extended over the belly, protecting the two crewmembers who sat in an armored "bathtub". Other sections of armor protected the underside of the engine nacelles and an apron extended up from the nose to the cockpit. The pilot was protected by an armored screen that was (in theory) capable of defeating a 13.2 mm machine gun bullet. The Ostrich had a maximum speed of 355 mph with a maximum range of 1,280 miles and a service ceiling of 28,500 feet. The only major fault with the Ostrich was that it was nose-heavy, a feature that gave pilots problems in pulling out of high-speed dives and resulted in numerous nosing-over accidents. The aircraft entered service in 1944 and remained in production until 1955.
Exports
In addition to serving with the Australian Air Force, it was widely exported, examples being sold to Canada, India, Thailand, South Africa, Argentina, Chile, Brazil, Ecuador, Venezuela, Turkey and Italy. Significant numbers were also supplied to Russia. It was widely valued for its reliability and its legendary ability to resist battle damage. Although numerous efforts to develop a more effective ligt bomber/close support aircraft were made (most notoriously, the Mosquito in India), these never showed any real increase over the all-round virtues of the Ostrich. The last service examples (in Ecuador) were withdrawn from use in the mid-1990s.
Variants
Ostrich FGA.1.
The first production version of the Ostrich, being delivered to RAAF squadrons in Russia from January 1944 onwards. This version can be distinguised by its original Beaufighter tail without the long fillet that distinguised later versions. It was armed with 4 23mm V-YA cannon in the nose and 8 .303 Vickers Mk.6 machine guns, four in each wing. A ninth .303 was on a pintle mount firing out of the rear cabin.
Ostrich CC.2
A variant of the Ostrich intended for RAAF Coastal Command. This was equipped to carry a torpedo under its belly as well as its battery of cannon, machine guns and wing rockets. The length of the torpedo and its weight distribution made the aircraft directionally unstable, the matter being addressed by the addition of a long fin fillet. This became standard on all future Ostrichs.
Ostrich FGA.3
An improved version of the FGA.1 with the extended fin of the Ostrich CC.2 but the wing guns replaced by six 0.5 inch Browning M2s. The rear defense gun was also replaced by a 0.5 inch M2.
Ostrich FGA.4
The definitive production version of the Ostrich. Early versions had proved extremely vulnerable to attacks from above and behind. In this situation, the heavy belly armor of the Ostrich was actually counterproductive in that bullets entering the crew's armored bathtub would bouce around inside, greatly increasing their lethality. The same applied to bullets hitting the engine nacelles that were only armored on their lower portions. Obviously armoring the whole aircraft was an imposisbility, the best that could be done was to improve the rearward defenses of the aircraft. This was done by increasing the caliber of the rear defense gun to 20mm (the weapon first being a Russian Shvak, later a B-20). The mounting itself was changed from a simple pintle to what was essentially a power-operated turret faired in with the crew station. This was a useful measure but the Ostriches vulnerability to attacks from above and behind remained a serious concern.
Ostrich FGA.5
Virtually identical to the FGA.4, the Ostrich FGA.5 had wing-mounted Browning 0.5 inch M3 machine guns in place of the M2s.
Early Development
The Ostrich was an Australian designed derivative of the Bristol Beaufighter with American R-2800 engines rated at 2,525 hp replacing its 1,635 hp Hercules radials. The Beaufighters were sent to Russia where they were used for gound support, the Russians calling them the "Australian Sturmovik". This became the Oz-Sturmovik then Oztovik and finally Ostrich. While the Beaufighter was an effective aircraft, it had many faults that needed addessing. These included a lack of directional stability and some viciously bad flying characteristics. DAP set about to correct these and, in the process, make full use of the extra engine power available.
When the improved version was built, the name Ostrich was formally adopted. In addition to its new engines, the Ostrich had a revised fuselage that featured two crew members,a pilot and a gunner-observer seated under a common canopy. There was provision for a third crew member but this was rarely used. The fuselage was lengthened aft and cut down. Armament consisted of four Russian 23mm V-Za cannon. Early versions carried eight .303 machine guns in the wings but these were replaced by six .50 Brownings in later versions. There were two hardpoints under the fuselage, each rated at 2,000 pounds and four more under the inner wings, the inner pair rated at 1,000 pounds, the outer at 500 pounds. However, total bombload was restricted to a total of 4,000 pounds. There were eight rocket launching rails under the outer wings, intended to carry RS-132 rockets.
The Ostrich featured a heavily-armored belly with a double layer of protection that proved capable of defeating rifle-caliber machine guns and small cannon anti-aircraft fire. This armor extended over the belly, protecting the two crewmembers who sat in an armored "bathtub". Other sections of armor protected the underside of the engine nacelles and an apron extended up from the nose to the cockpit. The pilot was protected by an armored screen that was (in theory) capable of defeating a 13.2 mm machine gun bullet. The Ostrich had a maximum speed of 355 mph with a maximum range of 1,280 miles and a service ceiling of 28,500 feet. The only major fault with the Ostrich was that it was nose-heavy, a feature that gave pilots problems in pulling out of high-speed dives and resulted in numerous nosing-over accidents. The aircraft entered service in 1944 and remained in production until 1955.
Exports
In addition to serving with the Australian Air Force, it was widely exported, examples being sold to Canada, India, Thailand, South Africa, Argentina, Chile, Brazil, Ecuador, Venezuela, Turkey and Italy. Significant numbers were also supplied to Russia. It was widely valued for its reliability and its legendary ability to resist battle damage. Although numerous efforts to develop a more effective ligt bomber/close support aircraft were made (most notoriously, the Mosquito in India), these never showed any real increase over the all-round virtues of the Ostrich. The last service examples (in Ecuador) were withdrawn from use in the mid-1990s.
Variants
Ostrich FGA.1.
The first production version of the Ostrich, being delivered to RAAF squadrons in Russia from January 1944 onwards. This version can be distinguised by its original Beaufighter tail without the long fillet that distinguised later versions. It was armed with 4 23mm V-YA cannon in the nose and 8 .303 Vickers Mk.6 machine guns, four in each wing. A ninth .303 was on a pintle mount firing out of the rear cabin.
Ostrich CC.2
A variant of the Ostrich intended for RAAF Coastal Command. This was equipped to carry a torpedo under its belly as well as its battery of cannon, machine guns and wing rockets. The length of the torpedo and its weight distribution made the aircraft directionally unstable, the matter being addressed by the addition of a long fin fillet. This became standard on all future Ostrichs.
Ostrich FGA.3
An improved version of the FGA.1 with the extended fin of the Ostrich CC.2 but the wing guns replaced by six 0.5 inch Browning M2s. The rear defense gun was also replaced by a 0.5 inch M2.
Ostrich FGA.4
The definitive production version of the Ostrich. Early versions had proved extremely vulnerable to attacks from above and behind. In this situation, the heavy belly armor of the Ostrich was actually counterproductive in that bullets entering the crew's armored bathtub would bouce around inside, greatly increasing their lethality. The same applied to bullets hitting the engine nacelles that were only armored on their lower portions. Obviously armoring the whole aircraft was an imposisbility, the best that could be done was to improve the rearward defenses of the aircraft. This was done by increasing the caliber of the rear defense gun to 20mm (the weapon first being a Russian Shvak, later a B-20). The mounting itself was changed from a simple pintle to what was essentially a power-operated turret faired in with the crew station. This was a useful measure but the Ostriches vulnerability to attacks from above and behind remained a serious concern.
Ostrich FGA.5
Virtually identical to the FGA.4, the Ostrich FGA.5 had wing-mounted Browning 0.5 inch M3 machine guns in place of the M2s.
Re: Australian & Canadian Aircraft
Hawker (Canada) Chinook
Early Development
Shortly after the Hawker Hurricane entered service, Hawker began work on its eventual successor. Hawker presented an early draft of their ideas to the Air Ministry who advised them that a specification was in the offing for such a fighter. The specification was released by the Ministry as Specification F.18/37 after further prompting from Hawker. The specification called for a single-seat fighter armed with 12 0.303 in (7.7 mm) machine-guns. A maximum speed of 400 mph (644 km/h) at 15,000 ft (4,572 m) and a service ceiling of 35,000 ft (10,668 m) were required. The prototypes was very similar to the Hurricane in general appearance, and shared some of its construction techniques. The front fuselage used the same swaged and bolted duralumin tube structure, which had been developed by Sydney Camm and Fred Sigrist in 1925. The new design featured an automobile-like side opening doors for entry, and used a large 40 ft (12 m) wing that was much thicker in cross section than those on aircraft like the Spitfire. The rear fuselage, from behind the cockpit, differed from that of the Hurricane in that it was a duralumin, semi-monocoque, flush-riveted structure. The all-metal wings incorporated the legs and wheel-bays of the wide-set undercarriage.
The prototype Tornado was first flown on 6 October 1939. Further flight trials revealed airflow problems around the radiator, which was subsequently relocated to a chin position. Later changes included increased rudder area, and the upgrading of the powerplant to the Vulture V engine. Hawker production lines focused on the Hurricane, and the completion of the second prototype (P5224) was thus significantly delayed. Work was brought completely to a standstill by The Halifax-Butler Coup on June 18 1940. Work on the Tornado was abandoned shortly after the coup took place and Hawker started a quiet process of shifting their key staff, files and design art to Canada.
Licensed production of the Hurricane had already started in Canada and airframes there were piling up waiting for Merlin engines that would now almost certainly never be delivered. The obvious replacement engine candidate for the Canadian-built Hurricanes had been the Allison V-1710, but American aircraft needed all available supplies of that engine. that left only the R-1830 as a candidate so the complex job of converting the Hurricane airframe to a radial engine had started. Halfway through the effort, Hawker engineers had arrived with blueprints for the Tornado. The only problem with the Tornado was that it also needed a British engines, the Vulture, which was unavailable. So Canadians and refugee Brits sat down together and redesigned the Tornado to use the American-built R-2600 engine.
Despite its unusual background, the Chinook turned out to be a successful aircraft. It retained the docility, stability and generally beingn flight characteristics of the Hurricane and had remarkably few vices. Its wide-track undercarriage proved a boon on the rough fields of Canada and, later, Russia. It went into production in early 1943, the last examples coming of fthe lines in late 1946.
Exports
Large numbers of Chinooks were supplied to Russia as Lend-Lease. Others were supplied to the Free Royal Air Force and Free French Air Force. Later in the war, more went out to the Netherlands East Indies, India and Thailand.
Variants
Chinook F Mk.1A
The original production version of the Chinook armed with 12 .303 machine guns. A proposed F.1B to be armed with 4 20mm cannon remained unbuilt due to the lack of suitable guns. It was powered by an R-2600-6 engines rated at 1,600 horsepower. This version lacked armor plate for the pilot and self-sealing fuel tanks and was not considered suitable for combat. However, it found a valuable use as the equipment for catapult-armed merchant ships and most of the initial production batch saw service in this role.
Chinook F Mk.2A
This aircraft was the first combat ready version of the Chinook having an uprated R-2600-12 engine rated at 1,700 horsepower, a bullet-proof winscreen, armored seat for the pilot and self-sealing fuel tanks. Again, it was to have been built in two versions, one armed with 12 .303 machine guns and the other with 4 20mm cannon but only the machine gun armed version was built. Large numbers of this variant were supplied to Russia as Lend-Lease. Russian pilots appreciated its strafing abilities although the .303 machine gun was considered to have too little punch for air combat.
Chinook F Mk.3B
The final production version of the Chinook finally received the 4 20mm cannon armament the pilots had been asking for. It was powered by an R-2600-22 engine rated at 1,900 horsepower. By the time it became available, the much superior Williwaw was on its way and most examples of the Chinook F.3B were supplied to other countries, either as Lend-Lease or as direct exports.
General Characteristics
Length: 32 ft 10 in
Wingspan: 41 ft 11 in
Height: 14 ft 8 in
Wing area: 283 ft²
Empty weight: 8,377 lb
Loaded weight: 9,520 lb
Maximum speed: 402 mph at 18,000 ft
Service ceiling: 34,900 ft (10,640 m)
Wing loading: max takeoff: 37.7 lb/ft²
Power/mass: max takeoff 5.38 lb/hp
Time to height: 7.2 min to 20,000 ft
Armament
Guns: Originally 12 × .303 in (7.7 mm) Browning machine guns. Later versions 4 × 20 mm Hispano cannon. All versions were equipped to carry two five hundred pound bombs
Early Development
Shortly after the Hawker Hurricane entered service, Hawker began work on its eventual successor. Hawker presented an early draft of their ideas to the Air Ministry who advised them that a specification was in the offing for such a fighter. The specification was released by the Ministry as Specification F.18/37 after further prompting from Hawker. The specification called for a single-seat fighter armed with 12 0.303 in (7.7 mm) machine-guns. A maximum speed of 400 mph (644 km/h) at 15,000 ft (4,572 m) and a service ceiling of 35,000 ft (10,668 m) were required. The prototypes was very similar to the Hurricane in general appearance, and shared some of its construction techniques. The front fuselage used the same swaged and bolted duralumin tube structure, which had been developed by Sydney Camm and Fred Sigrist in 1925. The new design featured an automobile-like side opening doors for entry, and used a large 40 ft (12 m) wing that was much thicker in cross section than those on aircraft like the Spitfire. The rear fuselage, from behind the cockpit, differed from that of the Hurricane in that it was a duralumin, semi-monocoque, flush-riveted structure. The all-metal wings incorporated the legs and wheel-bays of the wide-set undercarriage.
The prototype Tornado was first flown on 6 October 1939. Further flight trials revealed airflow problems around the radiator, which was subsequently relocated to a chin position. Later changes included increased rudder area, and the upgrading of the powerplant to the Vulture V engine. Hawker production lines focused on the Hurricane, and the completion of the second prototype (P5224) was thus significantly delayed. Work was brought completely to a standstill by The Halifax-Butler Coup on June 18 1940. Work on the Tornado was abandoned shortly after the coup took place and Hawker started a quiet process of shifting their key staff, files and design art to Canada.
Licensed production of the Hurricane had already started in Canada and airframes there were piling up waiting for Merlin engines that would now almost certainly never be delivered. The obvious replacement engine candidate for the Canadian-built Hurricanes had been the Allison V-1710, but American aircraft needed all available supplies of that engine. that left only the R-1830 as a candidate so the complex job of converting the Hurricane airframe to a radial engine had started. Halfway through the effort, Hawker engineers had arrived with blueprints for the Tornado. The only problem with the Tornado was that it also needed a British engines, the Vulture, which was unavailable. So Canadians and refugee Brits sat down together and redesigned the Tornado to use the American-built R-2600 engine.
Despite its unusual background, the Chinook turned out to be a successful aircraft. It retained the docility, stability and generally beingn flight characteristics of the Hurricane and had remarkably few vices. Its wide-track undercarriage proved a boon on the rough fields of Canada and, later, Russia. It went into production in early 1943, the last examples coming of fthe lines in late 1946.
Exports
Large numbers of Chinooks were supplied to Russia as Lend-Lease. Others were supplied to the Free Royal Air Force and Free French Air Force. Later in the war, more went out to the Netherlands East Indies, India and Thailand.
Variants
Chinook F Mk.1A
The original production version of the Chinook armed with 12 .303 machine guns. A proposed F.1B to be armed with 4 20mm cannon remained unbuilt due to the lack of suitable guns. It was powered by an R-2600-6 engines rated at 1,600 horsepower. This version lacked armor plate for the pilot and self-sealing fuel tanks and was not considered suitable for combat. However, it found a valuable use as the equipment for catapult-armed merchant ships and most of the initial production batch saw service in this role.
Chinook F Mk.2A
This aircraft was the first combat ready version of the Chinook having an uprated R-2600-12 engine rated at 1,700 horsepower, a bullet-proof winscreen, armored seat for the pilot and self-sealing fuel tanks. Again, it was to have been built in two versions, one armed with 12 .303 machine guns and the other with 4 20mm cannon but only the machine gun armed version was built. Large numbers of this variant were supplied to Russia as Lend-Lease. Russian pilots appreciated its strafing abilities although the .303 machine gun was considered to have too little punch for air combat.
Chinook F Mk.3B
The final production version of the Chinook finally received the 4 20mm cannon armament the pilots had been asking for. It was powered by an R-2600-22 engine rated at 1,900 horsepower. By the time it became available, the much superior Williwaw was on its way and most examples of the Chinook F.3B were supplied to other countries, either as Lend-Lease or as direct exports.
General Characteristics
Length: 32 ft 10 in
Wingspan: 41 ft 11 in
Height: 14 ft 8 in
Wing area: 283 ft²
Empty weight: 8,377 lb
Loaded weight: 9,520 lb
Maximum speed: 402 mph at 18,000 ft
Service ceiling: 34,900 ft (10,640 m)
Wing loading: max takeoff: 37.7 lb/ft²
Power/mass: max takeoff 5.38 lb/hp
Time to height: 7.2 min to 20,000 ft
Armament
Guns: Originally 12 × .303 in (7.7 mm) Browning machine guns. Later versions 4 × 20 mm Hispano cannon. All versions were equipped to carry two five hundred pound bombs
Last edited by Calder on Wed Mar 15, 2023 9:20 pm, edited 1 time in total.
Re: Australian & Canadian Aircraft
Hawker (Canada) Williwaw
Early History
Although the Chinook was basically a good design, the Anglo-Canadian design team under Sir Sydney Camm were disappointed with the wing which proved to be too thick in its cross section; this created problems with the airflow and inhibited the performance of the aircraft, especially at higher altitudes. In addition, the Chinook had the narrow fuselage associated with the liquid-cooled Merlin engine and the transition to the wider radial engine caused discontinuities and drag. A nthinner wing and a fuselage optimized for a radial engine seemed to offer potential for a much superior aircraft. The new laminar flow wing adopted for the Williwaw had a maximum thickness to chord ratio of 14.5% at the root tapering to 10% at the tip. By comparison the Chinook's wing, using a NACA 4 digit series wing section, was substantially thicker - 19.5% (root) to 12% (tip). The maximum thickness of the Williwaw wing was set further back at 37.5% of the chord versus 30% for the Chinook's wing. The wingspan was originally greater than that of the Chinook at 43 ft, but the wingtips were later "clipped" and the wing became shorter; 41 ft versus 41 ft 7 in. The wing planform was changed to an elliptical shape to accommodate the 800 rounds of ammunition for the four 20 mm cannons, which were moved back further into the wing. The new elliptical wing had greater area than the Chinook.
The thinner wing also displaced fuel tanks that had been fitted into the leading edge of the Chinook's wing. This greatly reduced fuel capacity but Hawker engineers added a new 21 in cm) bay ahead of the cockpit accommodating a 76 gallon fuel tank, giving a maximum of 360 gallons and an operational radius of 500 miles.
A further improvement of the Williwaw wing over that of the Chinook was the exceptional, flush riveted surface finish, essential on a high performance laminar flow airfoil. The redesigned main undercarriage legs were longer and had a wider track (16 ft) to improve stability at the high landing speed of 110 mph and to allow tip clearance for a new four-blade, 14 ft diameter propeller. The main undercarriage units were designed to incorporate a system of trunnions which shortened the legs as they retracted. The main wheels also needed new thin tyres in order to fit within the wing. Finally, the retractable tailwheel was fully enclosed by small doors. The most important change was the engine. The Williwaw received the R-2800-CB16 engine rated at 2,400 hp. This gave the aircraft a maximum speed of over 450 mph.
The first Williwaw flew on 28 June 1944. This was followed by the second, which first flew on 18 September 1944 and was assigned to engine development. The first production Williwaw was rolled off the line on 4 October 1944 with the type seeing service in Russian from February 1945 onwards.
Exports
During World War Two, exports of the Williwaw were limited to Lend-Lease supplies to Russia. Postwar, the very large numbers of American aircraft being dmped on the market at firesale prices depressed the demand for new-built aircraft. India bought a small number of aircraft in 1948/49 as an interim measure while its own programs were developed.
Variants
Williwaw F.1
The main production version of the Williwaw with details essentially the same as those of the prototypes.
Williwaw FGA.2
Ground attack version of the Williwaw powered by the R-2800CB-17 giving 2,500 hp. Wings were strengthened and provided with two extra pylons for a total bombload of 3,000 pounds in addition to its six or eight rockets. Additional armor installed under the engine and to protect the oil coolers.
Williwaw FAW.3
Radar-equipped nightfighter version of the F.1.
General Characteristics
Length: 33 ft 8 in
Wingspan: 41 ft 0 in
Height: 16 ft 1 in
Wing area: 302 ft²
Empty weight: 9,250 lb
Loaded weight: 11,400 lb
Max takeoff weight: 13,640 lb
Maximum speed: 452 mph at 18,400 ft
Range: 740 miles, 1,530 miles with 90 gallon drop tanks
Service ceiling: 36,500 ft
Rate of climb: 4,700 ft/min
Wing loading: 37.75 lb/ft²
Power/mass: 0.21 hp/lb
Armament
4 × 20 mm Mark II Hispano cannons, 200 rpg
2 × 500 lb or 1,000 lb (454 kg) bombs
8 × 3 in RP-3 rockets
Provision for 2 × 45 galon or 2 × 90 gallon drop tanks.
Early History
Although the Chinook was basically a good design, the Anglo-Canadian design team under Sir Sydney Camm were disappointed with the wing which proved to be too thick in its cross section; this created problems with the airflow and inhibited the performance of the aircraft, especially at higher altitudes. In addition, the Chinook had the narrow fuselage associated with the liquid-cooled Merlin engine and the transition to the wider radial engine caused discontinuities and drag. A nthinner wing and a fuselage optimized for a radial engine seemed to offer potential for a much superior aircraft. The new laminar flow wing adopted for the Williwaw had a maximum thickness to chord ratio of 14.5% at the root tapering to 10% at the tip. By comparison the Chinook's wing, using a NACA 4 digit series wing section, was substantially thicker - 19.5% (root) to 12% (tip). The maximum thickness of the Williwaw wing was set further back at 37.5% of the chord versus 30% for the Chinook's wing. The wingspan was originally greater than that of the Chinook at 43 ft, but the wingtips were later "clipped" and the wing became shorter; 41 ft versus 41 ft 7 in. The wing planform was changed to an elliptical shape to accommodate the 800 rounds of ammunition for the four 20 mm cannons, which were moved back further into the wing. The new elliptical wing had greater area than the Chinook.
The thinner wing also displaced fuel tanks that had been fitted into the leading edge of the Chinook's wing. This greatly reduced fuel capacity but Hawker engineers added a new 21 in cm) bay ahead of the cockpit accommodating a 76 gallon fuel tank, giving a maximum of 360 gallons and an operational radius of 500 miles.
A further improvement of the Williwaw wing over that of the Chinook was the exceptional, flush riveted surface finish, essential on a high performance laminar flow airfoil. The redesigned main undercarriage legs were longer and had a wider track (16 ft) to improve stability at the high landing speed of 110 mph and to allow tip clearance for a new four-blade, 14 ft diameter propeller. The main undercarriage units were designed to incorporate a system of trunnions which shortened the legs as they retracted. The main wheels also needed new thin tyres in order to fit within the wing. Finally, the retractable tailwheel was fully enclosed by small doors. The most important change was the engine. The Williwaw received the R-2800-CB16 engine rated at 2,400 hp. This gave the aircraft a maximum speed of over 450 mph.
The first Williwaw flew on 28 June 1944. This was followed by the second, which first flew on 18 September 1944 and was assigned to engine development. The first production Williwaw was rolled off the line on 4 October 1944 with the type seeing service in Russian from February 1945 onwards.
Exports
During World War Two, exports of the Williwaw were limited to Lend-Lease supplies to Russia. Postwar, the very large numbers of American aircraft being dmped on the market at firesale prices depressed the demand for new-built aircraft. India bought a small number of aircraft in 1948/49 as an interim measure while its own programs were developed.
Variants
Williwaw F.1
The main production version of the Williwaw with details essentially the same as those of the prototypes.
Williwaw FGA.2
Ground attack version of the Williwaw powered by the R-2800CB-17 giving 2,500 hp. Wings were strengthened and provided with two extra pylons for a total bombload of 3,000 pounds in addition to its six or eight rockets. Additional armor installed under the engine and to protect the oil coolers.
Williwaw FAW.3
Radar-equipped nightfighter version of the F.1.
General Characteristics
Length: 33 ft 8 in
Wingspan: 41 ft 0 in
Height: 16 ft 1 in
Wing area: 302 ft²
Empty weight: 9,250 lb
Loaded weight: 11,400 lb
Max takeoff weight: 13,640 lb
Maximum speed: 452 mph at 18,400 ft
Range: 740 miles, 1,530 miles with 90 gallon drop tanks
Service ceiling: 36,500 ft
Rate of climb: 4,700 ft/min
Wing loading: 37.75 lb/ft²
Power/mass: 0.21 hp/lb
Armament
4 × 20 mm Mark II Hispano cannons, 200 rpg
2 × 500 lb or 1,000 lb (454 kg) bombs
8 × 3 in RP-3 rockets
Provision for 2 × 45 galon or 2 × 90 gallon drop tanks.