Profile – CAC Boomerang

The Japanese assault on Pearl Harbour was announced on the early radio news on Monday 8th December 1941, (Sunday 7th Hawajjan time), and as soon as I reached my office that morning I called a meeting witti my senior design engineers, a team headed by Fred David during the war years. It was during discussions at that meeting that the concept of a new fighter aircraft was born.

We had by then built up a most competent design and development team, starting with the development of the Wirraway Advanced Trainer based on the North American NA33 Basic Trainer. In all, 811 Wirraways were delivered tb the Royal Australian Air Force, commencing early in 1939. Then followed the Wackett Trainer, and then the CA11 twih engined Torpedo Bomber using the P&W R1830 engine which was coming available from the CAC engine factory at Lidcombe, NSW . . .

During that second week in December, following Pearl Harbour, initial sketch plans were made and the concept of a single engine fighter emerged and by 24th December a Design Proposal was. . By that time the seriousness of the Japanese threat in the Pacific area became clearer and on 20th January 1942 formal approval of the design was received from the RAAF and production design was able to proceed”.

The man who created the preliminary ‘sketch plans’, in actual fact a three-view Engineering Layout for the new aircraft, was a young graduate aeronautical engineer, _Alan Bolton. He recalls: “. . . the man who deserves almost all credit for the ‘Boomerang’ and its concept was Fred David, the theh Chief Design Engineer at CAC. This man was a brilliant engineer and aircraft designer, a gentleman and fine teacher and leader. The following are the Circumstances, as I vividly recall them. . .

By the end of 1941, the Japanese were in full glorious flight, taking all before them on land, sea and in the air and there seemed that nothing would stop them from reaching Australia. The RAAF had no fighter except the Wirraway Trainer and these had been shot out of the sky at Rabaul. There was only one Hurricane Fighter on loan from the RAAF in our Air Force; the UK had its hands more than full and could not help while the USA was in similar straits.

Fred David had ironically been a very senior Design Engineer for Heinkel, had escaped Nazi persecution and gone to Japan, where he had_ again designed military aircraft,_escaping once more to Australia, when that country joined the Axis Powers. Things looked black indeed for Australia and no-one was more aware of this than Fred David.

Early in December 1941, (in fact, prior to Bill Air’s meeting) I recall vividly going into the Design Office at CAC early one morning, to find myself alone with Mr David. He was sitting at his desk, next to mine, in a very emotional state. I. sat down next to him and waited. After a short time, h_e said in his heavily accented German English – “What can we do Mr Bol_ton – what can we do?” I hadn’t the foggiest. idea, but waited. Then he said – “Design a fighter, to fight the Zero and use the biggest engine we make and as much as possible of the Wirraway jigs and tools. ”

Here was one man, a German, officially classified as an enemy alien and being forced (at that time) to report weekly to the police, calling for the immediate start on the design of a fighter for the belated defence. of Australia, a responsibility, surely, of the Air Force and the Government of the day and I was being given the job, at age 23. ”

The original Design Proposal of 24th December, 1941 emerged as follows: . .

• The objective was the production of a highly manoeuvrable aircraft which would be put into production with the least possible delay and flown within three months.

• Performance would be limited by the adoption of the R1830 engine, _the installation design for which could be taken largely from that already available for the CA11 twin engine bomber.

• There would. be no time to examine options and the design had to be fixed from the start for the whole first contract run. Wind tunnel testing was to be limited to a single model, to confirm aerodynamic balance, and the best drag reduction obtainable by Adjustment of external fairings. .

• To advance quickly to production, materials should be selected from the large stocks already on hand for the Wirraway contracts thus avoiding long delivery lead times. Any other requirements would be limited to those obtainable quickly from suppliers.

• To save tooling time the wing centre section should be patterned basically on the geometry of the Wirraway and a duplicate jig would be built for this substantial assembly. The Wirraway landing gear, already strengthened for this aircraft two years earlier, could be used unchanged. This item set the limit for all up landing weight.

• The tail units could be used. The fuselage would be of welded steel tube frame with a plywood fairing to avoid the time involved in development ai1d structural testing of a metal monocoque design.

• Armament would be four 303 Browning guns and two 20mm Hispano cannon, mounted in the wings. It was realised that there were no supplies of the Hispano guns available and CAC would plan to manufacture the requirements. for the Boomerang in a separate factory made available by the Government.

• Protection for the pilot would be provided by a Zirconium steel bulkhead and bulletproof fliel tank fitted in the fuselage.

• Though the programme proposed was a hasty one, there would be a properly controlled decision making process. All essential steps were subject to schedule check on a critical path analysis aimed at test flying the first aircraft in 100 days from the time production was commenced. In the event, the test programmed commenced after only 98 days from issue of the first production order.

Design and Development

All the foregoing preliminary concepts were set down to accompany Alan Bolton’s drawings for obtaining formal approval. However, he recalls that their design implications required:

“(1) Strengthened land gear supports.

(2) Strengthened wing centre-section within the Wirraway contours and profile, permitting the use of the Wirraway wing centre-section assembly jigs.

(3) A shortened fuselage, with other structural changes, particularly to house the large fuselage fuel tank.

(4) A new engine mount.

(5) The design of a completely new outer wing, (with a ‘laminar flow’ section for low drag, required wing loading and aspect ratio – all for highest possible performance and manoeuvrability) and to house the two Brownings and the 20mm cannon and their magazines – also for strength to withstand an acceleration of 10g, including a safety factor. The stressed skin outer wing and its stiffness requirements and the stiffness of the control systems were most important to achieve the strength and flying characteristics we wanted. A full-scale wing was built with all cutouts in skin and spars necessitated by the armaments and tested to destruction at the Aeronautical laboratory at Fishermen’s Bend under simulated aerodynamic load of 10g. I remember my wing showed signs of failure under test at about 9Q, which was about ideal. It only required a small local strengthening placed at the weak point (at a cut-out), to easily exceed 10g in strength. I also completed extensive wing and controls static stiffness testing, to ensure compliance with these requirements.

(6) The tail-units of the Wirraway could nOT be used modification, though their profiles were originally made 1dent1cal, allowing the use of the Wirraway jigs”.

The selected powerplant, a Pratt & Whitney R-1830-S3C-G Twin Wasp 14 cylinder radial, was the most powerful engine available in the country and necessitated the re-stressing of the forward fuselage for its installation. To cater for its correspondingly heavy fuel consumption, the aircraft’s 45 Imp gal (204. 61tr) self-sealing wing root fuel tanks were supplemented by a Imp gal (3181tr) self-sealing tank just behind the pilot’s cockpit and provision was made for the attachment of a flush-fitting plywood ventral drop tank of the same capacity if required.

Some interesting problems were encountered in providing the Boomerang with its two 20mm Hispano cannons. Because Australia might soon be isolated, it was obvious that this weapon had to be manufactured locally, but there was no sample of the gun immediately available, only a few handbooks which described it. Fortunately, through an extraordinary piece of luck, probably the only example in the country at the time was located. An RAAF sergeant, who’d had the cannon mounted on the back ?f his truck in the Western Desert, had brought it back to Australia from North Africa. Using this, and the handbooks, the CAC team was able to draught production drawings so that a local subcontractor, Harland Engineering, could manufacture the weapon. At the same time, the team designed for it a spring fed magazine and recoil-driven, belt feed booster. Alan Bolton recalls:

“All resources were harnessed very quickly – Drawing Office, Engineering Dept. , Production Dept. , etc. It was decided to run the great risk of putting the fighter straight into production on an assembly line, before the prototype was anywhere near completion, so that when it flew under test, production models were already coming down the ‘line’. ”

The first CA12 Boomerang (A46-1) began flight trials on May 29th, 1942, only sixteen weeks and three days after the approval for detail design to commence had been given. With CAC test pilot Ken Fruin at the controls, the machine completed taxi trials and flew for the first time. Fruin was delighted by the docile handling characteristics displayed by the aircraft and, although its level speed was not particularly fast, its manoeuvrability and climb rate exceeded all expectations. Tests showed that the machine had a maximum speed of 296mph (476km/h) at 7,600 feet (2,300m), a range of 930 miles (1,500km) and a service ceiling of 29,000 feet (8,850m). It had no serious vices and therefore required no major modifications. During tests with a loaded weight of 7,3681b (3,342kg) it displayed an initial climb rate of 2,940 ft/min (14. 93 m/sec) which was better that the Curtiss P-40E, the Hurricane 1 or the Spitfire 1. An altitude of 10,000 feet (3,048m) could be reached in four minutes and 20,000 feet (6,096m) in 9. 2 minutes. All in all a good effort given the extraordinary lack of time and resources available to the design team.

An initial production order for 105 aircraft was given to the CAC factory at Fishermen’s Bend, Victoria. A maximum effort was made to complete the first five Boomerangs as quickly as possible for RAAF evaluation. The first two featured an external oil cooler duct underneath the engine cowling, but this was incorporated into the cowling itself on later aircraft. An airscrew spinner was also introduced to improve engine cooling during a sustained climb. The first Boomerangs arrived at Mildura for No2 Operational Training Unit during the late summer of 1942.

Comparison Trials

A series of mock combats between the first Boomerang, a P- 40E and a P-39 Airacobra was arranged by the Department of Air. The resulting report stated that the Australian fighter was more manoeuvrable than the P-40 at 10,000 feet (3,048m), could turn inside it and that the speed advantage of the American fighter was not. enough to allow its pilot to fully dictate the type of combat. Although the P-40 was capable of out diving the Boomerang, the latter’s better pull out and superior cl!mb resulted in the two aircraft being level at the apex of their ensuing zoom. Once combat was joined, the P-40 proved unable to evade the Boomerang and could not break off the action except by a sustained dive.

The P-39 enjoyed a greater speed advantage over the Boomerang and its much better climb-and-dive capability initially allowed the Airacobra pilot to dictate the terms of combat, however, the Boomerang proved it could always out-manoeuvre its opponent at the same height in concentric attack.

Teething Troubles

At Mildura, No2 OTU began to encounter teething problems which stemmed from the speed with which the fighter had been evolved. In some aircraft the backplate of the airscrew spinner revealed cracks so the spinners were removed. This had a detrimental effect on performance because cylinder head temperatures could only be kept within the specified limits now by flying with the cooling gills partly open. The problem was eventually corrected by the provision of a heavier gauge backplate.

The guns showed a tendency to freeze at altitude. This was eventually overcome by diverting hot air from the exhaust system to the wing gun bays.

It was necessary to reposition the reflector sight because its original location obliged the pilot to sit bolt upright while sighting and shooting in a posture which increased the possibility of him blacking out. It was also a hazard in the event of a forced landing.

When they were hot, the brakes tended to lose their effectiveness and so also needed modification.

The locating pins of the ventral drop tank had to be strengthened to retain the tank in the correct position. Prior to this the tanks on some aircraft had shifted 90° in mid flight.

Besides these teething problems, inexperienced pilots at Mildura were encountering difficulties while landing the fighter and several aircraft were damaged as a result of ground loops. An investigation revealed that the majority of the landing accidents were occurring on cambered runways during crosswinds. The Boomerang, with its short wheelbase and substantial side area, had a tendency to swing if handled clumsily and this, coupled with the other factors, accounted for the high accident rate. Experienced pilots found that the swing could be counterbalanced by a combination of brakes and rudder accompanied by a short burst of power to increase rudder control. Once this procedure was adopted, the landing accident rate was reduced to a normal level.

Combat

The first unit to operate Boomerangs was No84 Squadron. Early in 1943, after a short period of working up, this unit, under the command of Sdn Ldr N Ford, was despatched to Horn Island off the Cape York Peninsula, from where it flew across the Torres Strait to provide standing patrols over the Allied base under construction at Merauke, New Guinea, some 200 miles (320km)

away.

Boomerangs made their first interception of enemy aircraft on May 16th, 1943, when two planes of 84 Squadron flown by F/O R W Johnstone and Sgt F J Stammer, on patrol over Merauke, met three Mitsubishi G4M ‘Betty’ bombers and attacked. The guns of one Boomerang refused to fire because of an electrical fault but the other managed to deliver a short burst from about 250 yards (230m) without any obvious effect before the Bettys melted into cloud cover and escaped. Return fire from the bombers was ineffective.

The Squadron kept up its standing patrols during June, July and August especially during the middle of the day when the airfield was most vulnerable. It was a long trip from Horn Island and the Boomerangs could only stay for about an hour because of their limited range. In July, a squadron of RAAF P-40 Kittyhawks arrived at Merauke to provide a permanent fighter defence.

On September 9th, an enemy force of 16 bombers escorted by 16 fighters heading for Merauke at 20,000 feet (6,100m) was detected by a newly installed radar station at Cape Kombies. Fourteen Kittyhawks of No86 Squadron and four Boomerangs of 84 Squadron took off to intercept. The Kittyhawks shot down three enemy aircraft without loss, although only four were able to fire their guns but the Boomerangs did not manage to reach the battle in time. Meanwhile, the Bettys bombed the airfield causing only minor damage to installations but destroyed a Boomerang on the ground.

Two other squadrons also received Boomerangs at this stage. These were 83 Squadron, which had been initially formed with a few Bell P-39 Airacobras supplied by the USAAF and 85 Squadron, which had initially operated the Brewster Buffalo. These two units were despatched to Gove, near Millingimbi in the Northern Territory, and Pearce, Western Australia, respectively. However, because they were retained for local defence duties on the mainland, these squadrons had no real chance to meet the Japanese in the air.

The leading Australian fighter ace, Group Captain Clive (Killer) Caldwell, who was in charge of Darwin’s Spitfire wing, was asked to test the Boomerang. In his trials, he found that it could not sustain a battle climb because of overheating by the time it reached 11,000 feet (3,350m) where he had to open the gills and ease off the throttle to cool it down. Upon resuming the battle climb, the same thing occurred after another four or 5,000 feet (1,500m) and the cooling procedure had to be carried out again, and so it went on . . .

Combat exercises with six B-25 Mitchells of the Dutch No18 Squadron, RAAF, at 12,000 feet (3,750m) revealed that the speedy Mitchells were too fast for Caldwell’s three intercepting Boomerangs.

Although its all-round performance was such that it was inferior to that of the standard Japanese fighters, such as the Mitsubishi A6M Zero or Nakajima Ki-43 Oscar, as a stopgap measure it could have been effective as a last line of defence (the role for which it was envisaged) against the less well armoured Japanese bombers, had the necessity arose. The speed at which the Boomerang was designed and built, with such limited resources available, was a considerable achievement in itself and the aircraft became a symbol of Australian defiance. Fortunately for Australia, the flow of American equipment was never interrupted and instead of being thrown into the fray against superior performance enemy aircraft, this tough tubby little plane found its role changed to one for which it was superbly suited – army co-operation.

Progressive Improvement

By June 1943, CAC had completed the initial order for 105 CA12 Boomerangs (A46-1 to -105) and commenced production of a second batch of 95 aircraft (A46-106 to -200) which incorporated the various minor modifications made in the light of initial service experience. This new order received the designation CA13 and modifications included: Replacement of the light alloy seat by one made from laminated timber; Replacement of fabric by light alloy for the skinning of the ailerons; Introduction of wooden wingtips; Fitting of Beaufort-type flame-damper exhaust tubes; Replacement of the hydraulic cocking system for the guns by a system in which the guns were cocked mechanically before takeoff; and Introduction of an external rear view mirror.

While production of the CA13 was proceeding, CAC initiated at development programme aimed at improving high altitude performance. An experimental aircraft was built as the CA14 (A46-1001) utilizing modified production components. The S3C4-G Twin Wasp offered its best performance with a high speed blower at 12,500 feet (3,800m), so a General Electric turbo-supercharger was installed in the rear fuselage. The location of the turbo-supercharger intake on the port side of the rear fuselage resulted in trim problems and some tailplane buffeting, but a gain in speed in the order of 20 percent was obtained at altitude. This arrangement was intended as a quick way to get the turbo-supercharger into the air for proving the complex system and allow flight performance testing and aerodynamic refinement while the CA14A engine and higher tech fan and air intake cowl was designed and built.

The CA14 and CA14A were the same aeroplane. The latter modification merely required the removal of the port side intake blister assembly and the fitting of the new modified engine and cowl and new ducting. Also replaced were the fin and rudder with a new larger area design. The production model would also have had a retracting tailwheel.

Bill Air recalls the work: ” . . . the experimental aircraft CA14A, detached from the Boomerang production line was the subject of a series of design changes aimed at improving the altitude performance. With the active encouragement of General George, then commanding the 5th US Army Air Force, a General Electric Model B-12 turbosupercharger was installed. This was taken from an unserviceable Liberator Bomber and flown especially to Melbourne for us.

The experimental development of the CA14A aircraft proceeded in two stages. The turbo-supercharger was inset on the righthand side behind the cockpit and fuselage tank area and the exhaust pipe extended back to this position. The intercooler was installed and fed with cooling air from a large external scoop on the left side of the aircraft. To improve engine cooling, the normal intercylinder baffles were ‘replaced with a closer fitting system, and the cooling flaps improved considerably.

We decided to test the aircraft with this installation to get some idea of the performance with the engine boosted by the turbosupercharger. This proved greater than anticipated but at altitude was limited by cooling for the P&W radial engine.

The next step was to mount a cooling fan driven by a three to one ratio gear box attached to the main engine reduction gear housing with a redesigned propeller shaft. This system was later used on the German Fw 190 fighter very successfully and appeared before the end of the war in Europe. To improve directional stability, the fin and rudder were enlarged with a flat top which distinguished this aircraft from the standard Boomerang.

It would have been essential to redesign the aircraft to incorporate a pressurized cockpit if this were to be taken further. Performance tests were done and the aircraft flown to 45,000 feet (13,700m) on the limited oxygen system available to us.

However, with hundreds of high altitude American aircraft arriving, there seemed little to be gained in further development effort and the aircraft, then number A46/1000, was delivered to the RAAF for experimental flying. ”

Alan Bolton recalls: “The CA14 prototype flew for many years for the Meteorological Bureau, taking high altitude weather observations, up past 40,000 feet, which was extremely high in those days. The aircraft’s most unusual feature was a fan, rotating at three times the propeller speed in the nose of the more streamlined cowl. This and other ducting design features, provided maximum ‘head’ for engine aspiration, engine and turbo-supercharger cooling and ·cooling for the inter-cooling air. Maximum speed was at the critical altitude of 35,000 feet (11,000m) and the production model would have had a performance higher than all contemporaries until the advent of the Mosquito. ”

One other Boomerang model left the Fishermen’s Bend factory before the last example of this aircraft was completed in January, 1945. This was the CA19 of which 49 (A46-201 to-249) were built. Changes to the first few were relatively minor, being largely confined to standardization of Dunlop eight ply tyres, and the omission of previously but an F24 vertical camera for tactical reconnaissance was installed into the rear fuselage of the eleventh CA19 (A46-211) on the assembly line and this became standard equipment for all subsequent aircraft.

Army Co-operation

Over the kunai and jungle of New Guinea, the Boomerangs began to set new standards for this type of work. Flying in pairs, they led bomber formations to specific pinpoint targets and guided artillery fire by dropping smoke bombs as markers and straffing with tracer bullets. Among the mountains and valleys of the Finisterre Range, pilots flew literally by the seat of their pants using the amazing nimbleness of their planes to duck in and out of valleys, swoop down on Japanese artillery postions and troop concentrations and finally zoom up and away to evade antiaircraft fire and call up a formation of Kittyhawks which they would then lead to the target.

Besides enemy anti-aircraft fire, low flying over rugged mountainous terrain and possible enemy aircraft, another problem faced by Boomerang pilots was the fact that under combat conditions their aircraft could easily be mistaken for Zeros. At least two Boomerangs of No4 Squadron, RAAF, were shot down by American fighters and two others were lost because of ground fire. One was chased from Lae to Salamaua by an aggressive P-38 Lightning. It made a forced landing on the airstrip at Salamaua but crashed into a ditch and had to be written off. The pilot fortunately escaped.

On another occasion, a Boomerang belonging to 4 Squadron was shot down by American gunners expecting a Japanese raid while it was flying a reconnaissance sortie over Salamaua. This time the pilot was killed.

In the middle of 1944, with the redeployment of Allied forces, 11 Australian Corps took the place of the XIV American Corps on Bougainville. In the air, the Australians were assigned support in the form of the New Zealand Air Task Force under the command of G/Capt G N Roberts. Since the New Zealanders had no army co-operation organization, the RAAF supplied an army co-op wing included in which was No5 Squadron equipped with 18 Boomerangs and 4 Wirraways.

The problem of aircraft recognition persisted and during the campaign when a Boomerang met RNZAF Corsairs, the prearranged signal was for the Boomerang to lower its undercarriage so the New Zealanders would not mistake it for a Zero. Nevertheless, the familiar pattern of operations was repeated and soon an excellent working relationship developed, born out of mutual respect for each other’s ability. Having located the target, the Boomerang pilot would lead his flight of Corsair fighter-bombers to the spot and, after marking it, he would then circle nearby observing the bombing and calling corrections over the radio. According to G/Capt Roberts:

“The excellent pinpointing by the Boomerangs has made the job a great deal easier and much more effective, while the accuracy of our bombing has improved immeasurably. ”

End of the Line

When production of the Boomerang ceased a total of 250 had be delivered to the RAAF from CAC’s Fishermen’s Bend factory and this stopgap fighter had earned for itself an honourable place in the history of Australian aviation. Bill Air sums up:

“It was always realized that the Boomerang would have inevitable performance limitations with the 1200hp P&W engine, the only one available at the time. The most serious drawback was high altitude climb. Some improvement was later obtained when the Lidcombe factory was able to offer a higher ratio supercharger on the R1830 engine . . . Contrary to the story put around at a later date, this was no ‘Panic’ programme. There was an understandable delay of a few weeks before the original authorization was given to us which enabled work to proceed, but this worked to our advantage giving time for the design team to think over our attack. (During this time, Alan Bolton continued the development of the design, working unofficially and on his own). We realized time was of the utmost importance, once the decks were cleared, the whole project went ahead in a most organized fashion. ”

After the war, in accordance with the Australian Government’s policy, the Boomerangs were sold for salvage and ended up as scrap or were melted down. Only one aircraft survived intact. This was Boomerang A46-30, a CA12 which had been used on patrol duties, by No85 Squadron in Western Australia. It was saved from the melting pot because towards the end of 1945 it was selected to feature in the film ‘Smithy’ suitably painted as the “Lady Southern Cross’, Kingsford Smith’s Lockheed Altair, VH-USB.

Afterwards it was turned over to the Australian Air League and left at Blacktown where it deteriorated into a state of disrepair and decay over almost twenty years. The Australian Restoration Group then found it and, in 1966, arrangements were made through a Group member, W/Cdr Keith Isaacs AFC, to have it returned to the RAAF and transported to Williamtown for restoration. This was duly carried out and for several years it was mounted as a gate guardian at the RAAF base. The effects of weather began to take hold but fortunately, it was realized that, because of the plane’s rarity, it should be protected and it was finally moved under cover to Point Cook. Eventually, it was acquired by the Australian War Memorial and at time of writing was proudly on display in the AWM’s Aircraft Hall.

A number of enthusiasts have managed to recover various parts of the indigenous fighter from several areas such as New Guinea and northern Australia and are in the process of using these to restore and rebuild some examples for display.

Note: The writer acknowledges with gratitude the assistance rendered by Alan Bolton and Bill Air in the preparation of this article. DN

CAC is now Hawker de Havilland Victoria.

Cac Project Team Involved In Designing the Boomerang

This team covered the CA12 and CA14 projects. Lawrence Wackett: General Manager; Bill Air: Chief Engineer responsible directly to General Manager; Fred David: Chief Design Engineer, head of the project team; Alan Bolton: Boomerang Design Engineer, overall design responsibility and stressing and detail of outer wings, tail surfaces, tailwheel, engine mount, turbo-supercharger installation and mountings, inter-cooler installation and all ducting. Structural strength and stiffness testing, etc; Ian Fleming: Flight Testing and aerodynamics; Joe Solvey: Detail wing aerodynamics; Doug Humphries: Wing centresection and undercarriage stressing; Colin Bellwood: CA14A engine modification, fan, spinner and cowl; Lionel Stem: Design copy and production of 20mm Hispano cannon; Ernie Jones: Chief Draftsman; Morrie Lodge: Project Engineer.

Commonwealth Aircraft Corporation’s CA12 Boomerang Specifications

Power Plant: . One Pratt & Whitney R-1830-S3C4-G Twin Wasp 14 cylinder two-row radial air-cooled engine rated at 1,200hp at 2,700rpm for takeoff, military ratings of 1,200hp at 4,900ft (1,494m) and 1,050hp at 13,100ft (3,993m) for five minutes, and normal rated output of 1,100hp at 2,550rpm at 6,200ft (1,890m) and 1,000hp at 12,500ft (3,800m). Hamilton Standard Series 3E 50 three-bladed constant-speed airscrew of 11ft 0in (3. 35m) diameter. Armament: Four 0. 303in (7. 7mm) Browning machine guns with 1,000rpg and two 20mm Hispano cannon with 60rpg.

Weights: Manufacturer’s empty, 5,373Ib (2,437kg); normal loaded, 7,699Ib (3,492kg); maximum overload, 8,249Ib (3,742kg).

Performance: Max. speed (at 7,368Ib/3,342kg): 302mph (486km/h) at 7,400ft (2,250m), 305mph (491km/h) at 15,500ft (4,700m); Max. Permissible dive speed: 410mph (660km/h); Recommended climb speed: 140mph (225km/h) between sea level and 7,000ft (2,134m); Stalling speed (engine off): 92mph (148km/h) with undercarriage and flaps up, 76mph (122km/h) with undercarriage and flaps down (engine at 2,000rpm), 79mph (127km/h)with undercarriage and flaps up, 69mph (111km/h) with undercarriage and flaps down; Initial climb rate (at 7,368Ib/ 3,342kg): 2,940ft/min (14. 93m/sec), (at 7,699Ib/3,492kg), 2,150ft/min (10. 92m/sec); Service ceiling, 34,000ft (10,363m); Normal range: 930mls (1,500km) at 190mph (306km/h) at 15,000ft (4,570m); Max. range with 70imp gal (318ltr) drop tank: 1,600mls (2,575km) at175mph (282km/h) at 10,000ft (3,050m). Max. endurance: 4. 9 hours. Dimensions: Span: 36ft 0in (10. 97m); Length: 25ft 6in (7. 77m); Height (tail down): 9ft ?in (2. 92m); Wing area: 225sq ft (20. 90m).

Boomerangs Under Reconstruction

As already mentioned, Boomerang A46-30, which is owned by the RAAF, is presently on display in the Australian War Memorial in Canberra, however, the aircraft is far from airworthy because many of its internal parts are missing and corrosion is present in the outer wings.

Meanwhile, several projects are in existence to resurrect more examples of the type and these include:

In Melbourne, the last CA19 Boomerang built, A46-249, has been a long term project of Richard Hourigan and CA12 Boomerang, A46-55, owned by aviation identity, Ron Lee, is up on its wheels with much work still to be done. Both are being prepared for static display.

In Brisbane, two ambitious projects are under way to obtain flying examples of a CA12 and CA13. Boomerang A46-54 is under reconstruction by Greg Batts and Matthew Denning is working on A46-122. Many hours have been devoted to both aircraft with many more to go. Problems have been described as ‘immense’ but each is tackled as it arises.

Hawker de Havilland Victoria, formerly CAC, holds the fuselage of A46-25 and other fuselages are known to exist in places from Darwin to Toowoomba. As Greg Batts, who supplied this information, remarked:”. . . You never know, one of these days some of these Boomerangs just might come back. ” Lets hope so.