The Other CAC Aircraft

Meanwhile, a much modified CA-4 known as the CA-11 Woomera was under construction, and was to become the new prototype. The Woomera first flew in 1944. An order for 105 slightly modified CA-11A Woomeras was placed by the RAAF, which was later reduced to 20, then cancelled due to the ready availability of American bombers. The Woomera featured two remotely controlled twin gun barbettes, situated at the end of each engine nacelle. The four. 303 in. machine guns were aimed with the aid of a sighting periscope from the rear of the cockpit, but unfortunately, problems were en­countered with this system initially.

The twin wheel main undercarriage legs folded rearward into the engine nacelles, which also housed two-250lb bombs. An additional bomb load of over 1000Ib which could include two 21-inch torpedoes could be carried externally. The Woomera was also armed with two. 303in machine guns and two 20mm cannons in the nose, in addition to an optional Vickers K gun in a ventral step. Long-range fuel tanks could be carried, replacing torpedoes or some bombs, the resulting range earning the Woomera the RAAF classification of long range fighter as well as torpedo bomber. The three-place Woomera had a maximum speed of 275mph, and a range of over 2000 miles. The sole CA-11 was reduced to components in 1946.

A sibling of the Wackett/Woomera Bomber project was an anti-tank aircraft designed in 1942. This Single Wasp powered twin-engined aeroplane also featured a remotely controlled Singun in the tail, but the main armament was a 40mm Bofors cannon in the nose, with 80 rounds of ammuni­tion. Before long it was realised that the aircraft was under­ powered, and was scrapped as a result.

Another project was investigated in 1942, namely that of a four-engined transport, to be powered by CAC-built Single Row Wasp radials. This aircraft bore a resemblance to the ear­ ly DC series of transports and had a maximum range of 1500 miles, and a gross weight of 25,2501b. None of these transports was ever built because manufacturing manpower never became available.

The successful Boomerang fighter of 1942 opened the door to further fighter design work. At first a high altitude supercharged version of Boomerang was designed – the CA-14. This aircraft was also powered by a Pratt and Whitney Twin Wasp, but was fitted with a General Electric B2 turbo supercharger, which gave the CA-14 a top speed of 372mph (cf 305mph of production Boomerang. ) A prototype CA-14 was built and later fitted with a square tail to become CA-14A. However, this fighter was dropped, and a new design, the CA-15, was adopted.

It was originally intended to use the Pratt and Whitney R- 2800 engine of 2300 horsepower to power the CA-15, and studies of various versions of the R2800 were carried out, but due to the unavailability of this engine, the Rolls Royce Grif­ fon Mk 61 was chosen. The Griffon 61 was to be used until an advanced Griffon with three speed supercharger became available in Australia. A prototype CA-15, A62-1001, was built and first flew in March 1946. The CA-15 incorporated the NACA aerofoil section and was armed with six machine guns mounted in the wings. It had a top speed of 442mph and could outrange, outclimb, and fly higher than the P-51 Mustang. The CA-15 was considered by many, including Sir Lawrence Wackett, to be the most advanced piston-engined fighter ever built. In fact when Lord Hives, the head of Rolls Royce, visited Australia and inspected the CA-15, he com­mented that it was the best example of Griffon installation he had ever seen. However, by the time development was com­plete, the CA-15 had lost its original priority to the jet powered aircraft about to be introduced into RAAF service and the sole CA-15 was broken up in the 1950s.

In 1948, design began on an all-weather jet fighter and was to be the most advanced project ever undertaken by CAC. The project was designated CA-23. Early proposals were for a small, two side-by-side seat low wing single engined air­ craft, armed with two 30mm cannon and fitted with A1 Mk nine tracking radar. However, this proposal fell to a twin engined jet with highly swept wing and a T-tail. The two crew were seated in tandem. This design in turn was superseded in 1949 by a similar aircraft to be powered by two Rolls Royce Avon engines, in accordance with RAAF Specification AC. 79. A Rolls Royce Tay-powered version was also investigated. The final CA-23 design, with two Avons, featured an all-movable tail plane, swept wings, and four 30mm cannon. The CA-23 was similar in shape and design to the English Electric Light­ ning which first flew in 1954. The CA-23 was to be fitted with a video radar relay interception system developed in Australia by Dr E. G. Bowen. Model testing was undertaken in both Australia and England before the project was cancelled, after five years and 150,000 manhours of work, in 1953.

Following the CA-23 project were a number of designs, the first of which was for a small, high-performance single-seat fighter. The Rolls Royce RA. 7 was chosen to power this air­ craft, giving it a speed of 750kts. The swept wing had a span of only 17ft Jin and included integral fuel cells containing all the internal fuel. The aircraft was armed with two 30mm can­ non, with gunlaying radar. This design was later cancelled.

The design team then concentrated their efforts on a rocket-powered interceptor capable of attacking a 600mph bomber at 55,000 feet. Various configurations were studied, and the project was coded AA. 59 until November, 1951, when the design was modified to become AA. 60. The design chosen was a swept-wing aircraft powered by two alcohol/oxygen rocket motors, giving a maximum speed of Mach 2, and an in­ credible rate of climb of 47,000ft/min (cf Avon-Sabre 12,000ft/min) which could be maintained for 70 seconds. An improved design powered by a four-chambered Reaction Motors XLR-11-RM-5 giving 4 x 3000Ib thrust, and a ground run of only 200 yards. The wing span of this aircraft was only 15 feet, with a length of 31 feet. The fuel load was to be carried in rubber bags (alcohol) and an aluminium tank (LOX) and totalled 375 gallons. Tricycle undercarriage was used, the main wheels retracting into the outer wings. Armament was provided by six 3 inch Oerlikon rockets. The rocket intercep­ tor concept was dropped when military thinking turned away from such aircraft.

In 1954 proposals were made by CAC for an aircraft to complement the Avon-Sabre fighters coming into RAAF ser­ vice. This supersonic aircraft, named the Warrior, was design­ ed to have the commonality of parts with the Sabre, also built by CAC. The Warrior was to be powered by the Rolls Royce Avon RA-24 of 11,250Ib thrust, with reheat. It was a thin wing design with a tricycle undercarriage, the main wheels retracting into the wing tip fuel pods. Armed with two 30mm cannon and 2200Ib of external stores, this aircraft was certainly an aggressive machine, and could attain a speed of Mach 2.

The Warrior design was developed and modified, and an advanced version could attain an altitude of 60,000 feet in com­ bat situations, with a combat radius of 400 nautical miles. A rate of climb of 34,000ft/min could have been achieved for short intervals. In ground attack configuration, the fighter could carry either eight rockets or a number of bombs. Further versions saw the wing pods being replaced by air-to­ air missiles, and a semi-flush armaments bay incorporated un­der the fuselage. The Warrior could have carried nuclear weapons.

All the systems and mechanical units in the Warrior were of Sabre origin in order to save costs, minimize development risks, and to enable Sabre maintenance facilities to be utilised. The Warrior was to be constructed using stainless steel for most structures. Unfortunately, none of these aircraft were ever constructed.

While the CA-23 project was in progress, a new trainer was being designed at CAC to replace bo h the Tiger Moth and the Wirraway. Named the Winjeel, two prototypes and 62 production aircraft were built between 1955 and 1957. At first, plans were made for the Winjeel to take a locally made engine – the CAC Cicada – but the Pratt and Whitney Junior Wasp was eventually chosen.

A number of innovations and modifications of the Winjeel were considered by the design staff. A version with tricy­cle retractable undercarriage was one of the first to be in­ investigated. (Production CA-25 Winjeels had fixed undercarriage). Another Winjeel development facilitated the addi­tion of a stretcher in place of the fourth seat. This air am­bulance variant was to be fitted with a starboard stretcher loading door just aft of the wing. The stretcher slid into place on curved rails to be located next to the third seat which was to be occupied by a medical attendant. The outward shape and canopy remained the same. (NB. Only three seats were ever fitted to the RAAF Winjeels).

A six-seat Winjeel version was also studied. This aircraft had an extensively modified cockpit – a door was added and the normally sliding cockpit remained fixed. A separate entry hatch was provided for the crew. The six-seat Winjeel would have flown at 175mph, with a cruising speed of 158mph at 5000 feet.

Yet another Winjeel development was a re-engined ver­sion, powered by two Turbomeca Aspin II turbine engines set side by side in the nose. Each engine produced 800Ib thrust, which increased the maximum by 190mph to an incredible 380mph. The undercarriage of this version retracted semi­ flush into wing-mounted post additions. Like the other Win­ jeel developments, no prototypes were ever built.

In 1967, the CAC Ceres agricultural aircraft went into production, and after its success, design studies proceeded with the modification of the basic Winjeel for agricultural use. This aircraft was to be powered by a single Pratt and Whitney PT. 6 turboprop engine, enabling a hopper load of 3350Ib to be carried. (Ceres – 2360lb. ) The nose and centre section were redesigned, but the remainder was of Winjeel origin. This design was also unsuccessful.

RAAF thinking in the 1950s was for all-through jet train­ ing. CAC, with this proposal in mind, began the investigation of a new Winjeel design powered by a turboprop engine. The powerplant chosen was the Rolls Royce Dart, which is used in many civil and military aircraft. Fitting the Dart to the Winjeel is something like putting a Jaguar V-12 engine into a Mini. This redesigned Winjeel was equipped with retractable un­dercarriage, and retained the proven structures of the CA-25 Winjeel. However, before this aircraft could be tested or even constructed, the design team abandoned the Dart Winjeel in favour of an entirely new pure jet concept, proposed in 1953.

The new design was planned around a Rolls Royce Derwent centrifugal jet turbine. Side-by-side seating, preferred by the RAAF at that time, was incorporated. The Derwent trainer, with intakes situated in the wing roots and a tail jetpipe, had a maximum speed of 500kts. It was a small air­ craft with a wingspan of 28½ feet and a length of 30 feet. A variant of this aircraft with two Turbomeca Aspin II engines was considered, this time with the jetpipe located under the mid-fuselage. The Aspin version had the attraction of twin engine reliability and training capabilities, and of fuel economy, but it lacked the power of the Derwent. The Aspin trainer had a top speed of only 375mph. Another version, powered by the Armstrong Siddeley Viper was investigated and was similar in form to the Derwent trainer. No orders were placed for the CAC jet trainers, as the Macchi was chosen as the RAAF advanced jet trainer.

Back in 1953, studies were made into the requirements for a feeder-liner aircraft. CAC worked on an aircraft for such work, and produced a design known as the Wallaby – “the aircraft for lesser airlines”. The Wallaby, a low-wing, 12 to 15-passenger aircraft, was powered by two CAC Cicada radials of 450 horsepower each, and an auxiliary Turbomeca Palas jet engine of 350Ib thrust. The Wallaby weighed 11,600Ib, and would have had an effective range of 720 miles. It was fitted with a tricycle undercarriage and could be converted from passenger to freight or executive form. A 19-passenger Wallaby was also considered. Again, as with some previous designs, CAC found resistance to local design, and no firm assurance of sales existed. The Wallaby was considered by those associated with it to be years ahead of its time. No Wallaby was ever built.

Sometime after the failure of the Derwent trainer designs, CAC investigated the design of a four seat jet trainer capable of light transport and communications duties. The result was an attractive low wing aircraft with T-tail and in­ corporating wing tip fuel tanks. It was to be powered by a single General Electric J. 85 engine, or a development of the Rolls Royce RB. 108. This aeroplane would have had a speed of 400kts, and a range of 1050 nautical miles. The project was un­ successful, and again no aircraft were built.

In 1967, CAC initiated the design of a supersonic delta wing advanced trainer. The trainer’s role was to replace the advanced training stage currently undertaken in the Macchi. Little work on supersonic delta trainers had been done overseas. This design, designated CA-31, was a small tailless double delta wing trainer, with a span of only 21 feet. Various power plants were considered, including the SNECMA M45.B3, the Rolls Royce Adour, and twin General Electric J.85s, before it was decided to fit the Adour. A single J. 85 had originally been chosen because of its excellent thrust-to-weight ratio of 7. 6, but the high fuel consumption of the engine ruled it out. The Adour would have given the CA-31 a speed of Mach 1. 5.

The attractions of the CA-31 are numerous. Firstly, the current Macchi jet trainer is subsonic, so a vital supersonic training capability is lacking, a gap that the CA-31 could fill. The tailless configuration of the CA-31 would enable it to be used as a conversion or delta characteristic trainer for the Mirage and F111, a phase now being undertaken in the dual-seat Mirage III. The CA-31 shares a high rate of role with high-performance aircraft, enabling roll coupling recovery technique training to be performed without using the expen­ sive II IDs. This part of training cannot be done in the conven­ tional Macchi. At present, a large amount of money is spent using operational aircraft for training purposes, an un­ necessary expenditure which could be saved with the in­ production of the CA-31. The CA-31 also has a close support capability in case of national emergency.

A single-seat version could also be built if the need arose, the space gained being used to house a large fuel cell and additional operational equipment. The close support CA-31 could carry a 4000Ib bomb load and could be equipped with 20 or 30mm cannons. A lot of work was done by CAC on the CA-31 project, including a full-scale mock-up construction. A carrier-based naval version was also planned, and if this air­ craft had been chosen by the RAN, the Fleet Air Arm would have had supersonic capability for the first time. The RAAF decided against the introduction of the CA-31, and as a result, the proposal was dropped.

In 1968, CAC commenced design of another advanced operational and close support aircraft – a collaborative pr­oject with the British Aircraft Corporation. This aeroplane in­ incorporated a variable geometry wing (swing wing), and the project was coded AA107. Design work on the AA 107 was carried out at Warton in the United Kingdom in 1968, and later at CAC until the project was cancelled in 1970. The BACICAC AA107 was a two-seat, single engined aircraft with a movable tail11Jane. A full-scale mock-up was constructed at CAC in late 1968, but no prototype was built.

After 1968, CAC was engaged in preparation for the planned manufacture of 191 Bell JetRanger (Kiowa) helicopters under licence for both civil and military purposes. The number was later reduced to 56 military types. After 1970, due to a lack of government financial support for new local designs, the CAC design group worked on a number of plans for the revamping of the Macchi jet trainer. These proposed variants were designated CA-30-2A,-28,-2C,-2D,-2E and -2F. Most of these versions incorporated higher thrust and lower fuel consumption engines, and a dropped nose to provide better visibility from the rear cockpit. One Macchi modifica­ tion featured clipped wings and the removal of the tip tanks. All versions included modifications to extend the fatigue life extensively.

In 1975, an entirely new concept was proposed by CAC. The new aircraft, coded AA332 and AA336, was a Light Military Support (LMS) aircraft which could also be used for civil duties. The LMS aircraft design was a twin piston engined aeroplane with IFR and rough weather operating capabilities. The two crew were seated in tandem in a cabin slung under a high single fuselage boom. A variety of fuselage modules could be attached to the cabin, enabling the LMS to act in the roles of close support, forward air control, photo/radar, arm­ed, or visual reconnaissance, border surveillance, coast guard, helicopter escort, paratroop or supply dropping, and pilot and navigation training. Civil purposes could include air am­bulance work, utility transport, survey and mapping, pest controlling, aerial search, air-sea rescue, police work, and TV reporting work.

The military LMS could, for example, be fitted with an observing module, and a movable gun turret under the rear fuselage, in addition to nose-mounted guns. The LMS would have cost about $A200,000 plus an additional $A50,000 for military equipment. The LMS was to be built and developed with an Asian partner, but financial support was not forthcoming. The three-seat basic LMS would have had a top speed of 230 knots at 10,000 feet, with a maximum range of 1200 n. miles without ferrying tanks. (7. 6 hours endurance. ) It was to be powered by two wing-mounted Continental TS10- 520 engines of 300 horsepower each. The LMS was not in any way meant to be a competitor to the GAF Nomad and did not possess STOL capabilities.

In early 1977, CAC proposed the concept of a Light Weight Trainer (LWT) to illustrate the procurement and operating cost savings possible with a small trainer having similar performance to the M8326H Macchi. The LWT was meant to be smaller than the British Folland Gnat and would have been powered by one or two small, modern turbofans. Preliminary studies indicated that a saving of $A100.0m could be achieved with a fleet of 100 LWTS over a 10 year period. The LWT concept gave way to a more versatile proposal – the CA-X.

In September 1977, the concept of a universal lightweight trainer was put forward by Mr James Caterson of CAC. Known as the CA-X, this twin-boom, two-seat trainer was, like the LWT, meant as a replacement for the CA-30 Macchi air­ craft in service with both the RAAF and the RAN. The CA-X incorporates a blended wing body and lightweight design and has a turbofan powerplant.

This remarkable aircraft consumes about half as much fuel as the current trainer, yet has a rate of climb over three times that of the Macchi. The CA-X can easily turn inside the Macchi, and also has a greater maximum specific range. Such performance enables faster recovery from training manoeuvres, such as dives, and therefore allows more manoeuvres to be performed at the same time. The low fuel consumption also means that a large reduction in training costs could be achieved. The CA-Xis meant to take over some of the duties of the CT-4 in addition to the Macchi, the CT-4 Airtrainers being used as a screening stage for pilot training, after which all flight training is to be carried out on the CA-X. Design work is still being undertaken at CAC on the CA-X trainer which obviously shows much potential. The CA-Xis a strong contender for the eventual Macchi replacement.

The failure of all these aircraft to reach production is not generally due to any fault in their design, nor is it due to a lack of technical ability at CAC. The problem lies in the opposition Australians show towards indigenous products and the lack of adequate funding for prototype development and testing. Unfortunately, due to the small size of Australia and its air­ craft market, this money is not available. Obviously, vast amounts of money cannot be spent on design studies, but a stronger preference must be shown towards local products by both Government and industry for success to be achieved in Australian aircraft manufacture.