Jabiru Mk.1

The Aerodynamics Department of the Royal Aircraft Establishment (RAE) in the UK and the Aerodynamics Division of the Weapons Research Establishment (WRE) in Australia agreed in 1958 to collaborate on the design and development of a rocket to carry out research in hypersonic (Mach 5 or greater) aerodynamics.
It was determined that this vehicle would be a three-stage rocket utilizing a Rook II solid-propellant motor for the first stage, a Gosling IIN for the second stage and a Lobster 1A for the final stage. Initially, the RAE was to undertake the development of a two-stage Rook-Gosling vehicle, while the WRE worked on a Gosling-Lobster combination.
Once testing of these two-stage vehicles proved satisfactory, they would be combined to form the three-stage rocket, which was initially known as Jaguar in the UK and Jabiru in Australia. Because of confusion with a US air-launched sounding rocket of the same name, as well as the British fighter aircraft, the name Jaguar was eventually dropped in favour of the Australian designation.

Developmental program
The RAE development trials commenced with single-stage and two-stage firings carried out at Aberporth. The first Rook vehicle was launched in June 1959 and the first 2-stage Rook-Gosling vehicle (known as the Leopard), with a live Gosling motor, was launched in May 1960. The last test before the initial 3-stage attempt was the Jaguar G1 launched on 17 August 1960 with a live first-stage and inert second and third stages. Within this preliminary program, one single-stage Rook motor, designated Rook 1j, was launched from Woomera for testing new aluminium alloy fins for the Rook motor.
Meanwhile, the WRE fired six Gosling-Lobster vehicles from its Woomera range between July 1959 and September 1960. On these vehicles, the Gosling was stabilized by fins, rather than the skirt that would be used on the operational three-stage vehicle.

Jabiru Mk.1
All versions of the Jabiru were based upon the use of a Rook solid motor - a fast burning variant of the Raven motor - as first stage. The Rook II used in the Jabiru Mk.1 vehicle was 5.4 m high and weighed 1170 kg with 866 kg of propellant. It delivered a total impulse of 1735 kNs in 7 sec. The second stage used a 25.4 cm Gosling IIN motor weighing 292 kg with 184 kg of propellant and delivering 400 kNs in 3.5 sec. The motor used for the third stage was named Lobster, presumably because its leading surfaces glowed red under conditions of high heating. With 26 kg of propellant, it delivered 58 kNs in 2 sec. First stage stabilization was achieved by three fixed fins, similar to those used on the Skylark sounding rocket. The second and third stages were stabilized by conical skirts.
The complete vehicle was between 11.7 and 12.0 m high and weighed about 1670 kg. If used as a sounding rocket, the Jabiru Mk.1 could carry a 9 kg payload to a height of more than 800 km.

The research program for the Jabiru Mk.1 was focused on measurements of heat transfer and pressure distribution on different nosecone shapes. In a typical flight, the main test period commenced with second-stage ignition and ended when the speed of the coasting third stage fell below Mach 4. The flight plan was devised so that this period remained in the 25-30 km altitude range.
Nine three-stage Jabiru Mk.1 were fired between December, 1960 and February, 1964. Of these, three were test vehicles, three carried RAE experiments and three carried WRE aerodynamic heating experiments. One additional firing carrying the designation 'Bonorong' was launched within the Jabiru program.

Jabiru Mk.2

Jabiru Mk.2
The Jabiru's performance as well as the size of the instrumentation compartment revealed itself inadequate for the follow-up program and made the development of an improved vehicle desirable. This second-generation vehicle would have to have approximately the same performance as the Mk.1 in terms of altitude and speed, but be able to carry pay-loads up to 100 kg, thus enabling a greater variety of experiments to be carried out.
The new vehicle, designated Jabiru Mk.2 but also known as Aero-Mach, used an improved version of the Rook in its first stage. The Rook III was identical in size to its predecessor. For the second stage, the Gosling was replaced by a Goldfinch II motor, with the same diameter as the Rook and 2.16 m long. With 307 kg of propellant, it delivered a total impulse of 694 kNs in about 4 sec. The upper stage was an improved version of the Gosling, the Gosling IV, carrying 190 kg of propellant. First and second stage stabilization was achieved by fixed triple-fin configurations, with the second stage fins offset by 600 from those of the first stage. The third stage was stabilized by a combination of four wedge fins and a conical skirt.
The Jabiru Mk. 2 vehicle was 12.9 m high and weighed 2190 kg. Although not developed as an upper atmosphere research rocket, it could carry 45 kg payload to a height of approximately 540 km.

Two alternative flight plans were used :
i) The "upward firing" trajectory, in which the vehicle coasted, after Rook burn-out, to an altitude of about 9000 m. The Goldfinch and Gosling then successively ignited, accelerating the upper part to a maximum speed of 2500 m/sec near 24,000 m. After burn-out the final stage continued climbing, to reach a maximum altitude of about 290 km.
ii) The "horizontal" trajectory, in which the vehicle coasted, after Rook burn-out, until the peak of the trajectory (about 20 km) was passed and the vehicle was inclined downwards at a small angle. The Goldfinch and Gosling successively ignited, accelerating the upper stage to a speed of about 2300 m/sec. Hypersonic speed was maintained for approximately 30 sec after third stage burnout.

Ten Jabiru Mk.2 were fired between October, 1964 and April, 1970. Of these, two were test vehicles, six carried RAE experiments and two carried WRE experiments. One additional firing in April 1969 is sometimes reported and may have been a test flight to prove a new kind of launcher operational.

Despite the formal cessation of the HRV Joint Project in 1970, the RAE and WRE continued to collaborate on hypersonic research. In 1971, a series of additional experiments dealing with the aerodynamic heating of hemispherical-shaped objects was undertaken using Jabiru vehicles. They were preceded in July by the single-stage FFARV (Free Flight Aerodynamic Research Vehicle) that used a Rook motor and reached a maximum sped of Mach 5.5. Two Jabiru flights designated Jabiru J-1 and J-2 occurred at the end of 1971, associated with the FFRV project. These rockets, used to launch a payload which consisted of a 190 mm diameter hemisphere followed by a cone-cylinder weighing 104 kg, achieved Mach 8.3.

Jabiru Mk.3
In order to increase the time interval during which the Mach number could be maintained above 6, it was decided to investigate the feasibility of using a vehicle based on two Rook motors in tandem. Under the conditions described for the J-1 and J-2 flights, this new Rook-Rook vehicle would achieve Mach 8.7. Subsequently the hemispherical nose diameter for the ablation experiments was increased to 324 mm so the achievable maximum Mach number was still 8.2. The same vehicle was to be able to carry out model aerodynamic stability tests at Mach 7.3.
The Rook IIIA motor used as the first stage for the Jabiru Mk.2 was retained in the Mk.3 variant, with the same fin assembly. The second stage of the new vehicle used a Rook IIIB motor, which was virtually identical, except for an external insulation. However, its fin shape was different and were placed in-line instead of offset, as in the Mk.2
The overall vehicle with the ablation experiment payload was 12.75 m high and weighed 2640 kg.

The Jabiru Mk.3 flights were associated with two series of experiments designed by the RAE:
i) Two ablation experiments, in "upward firing" configuration, in 1973. They intended to subject a recoverable 324 mm diameter hemispherical nose cap to hypersonic flight conditions,
ii) Three flights, in "horizontal trajectory" configuration in 1974, to measure the aerodynamic stability properties of a separating 123 kg free-flight model at Mach numbers up to at least 7.

1974 saw the end of the Jabiru program. Across its lifespan of some 15 years, the data gathered from Jabiru firings contributed to the larger body of data on hypersonic aerodynamics and ablation effects that was amassed at Woomera.

Note : Rook started its career as a motor for projecting models of supersonic aircrafts. The first launches occurred in June 1959 from Aberporth. It was then used as booster for the two-stage Leopard rocket, the upper stage being Goslings. Rook was fired 70 times altogether, in 65 flights and 16 different vehicle design. It was also proposed as booster for the Skylark 14 and 15 sounding rockets, but these projects were never born.