The RAAF flew Neptunes from 1951 until 1978, first with 11 Squadron and then with 10 Squadron. A land-based maritime patrol aircraft designed in the flying boat era, the Neptune was based on a 1941 study by Lockheed's Vega subsidiary. The prototype first flew in May 1945 and operational aircraft began entering service in 1947.

Fairly large for its time, the Neptune was a mid/high-wing monoplane with tricycle landing gear, underwing hard-points and a bomb bay (which may be the reason it was often mistakenly called a bomber). Power was provided initially by two 2300 hp (1715 kw) Wright R3350 Duplex Cyclone engines (which decodes to 18 cylinders in two radial rows of 9 totalling 3350 cubic inches displacement – more than 50 litres per engine) driving variable pitch propellers with reverse thrust.

On 1 October 1951 a Neptune, 'the Truculent Turtle', landed in Columbus Ohio after flying 11, 236 miles from Pearce, WA, in 55 hours. To do so it carried 8,600 US gallons of fuel, which raised the take-off weight from a standard 58 000 lbs to 84 000 lbs, and used jet assisted take off (JATO) rockets to get airborne. This amazing feat - 12 hours in a relatively noisy, un-pressurised Neptune was more than enough for most aircrew – provided a taste of what was to come. Successive variants grew to over 80 000 lbs AUW and jets and water injection were added to provide extra power for takeoff and emergencies.

Lockheed Neptune

The resultant noise on take off from 'two that turn and two that burn' was distinctive and unforgettable for all but the deaf. After climb out at over 200 knots the jets were shut down and speed reduced to about 180 knots for cruise, making the Neptune one of very few aircraft that climbed faster than it cruised.

RAAF Neptunes were fitted for ASW, surface ship detection and general reconnaissance. Twelve P2V4/5 (later designated P2E) aircraft entered service with No.11 Squadron, in Pearce WA, in 1951. At first powered only by two R3350 radials, all were later retrofitted with Westinghouse J-34 auxiliary jets. Having moved to Richmond, 11 Squadron lost an aircraft and crew in 1959 during an air test when a runaway engine fire burned through the wing and the aircraft crashed within sight of the base. The remaining 11 aircraft were replaced by 10 Orion P3Bs in 1968 and the squadron relocated to Edinburgh, SA.

In 1962 10 Squadron in Townsville received 12 P2V7 (later SP2H) aircraft. The P2V7 had a more rounded cockpit canopy, more streamlined tip tanks and the same tactical and navigation displays and acoustic detection equipment as the early Orions. This made it a very effective ASW aircraft for its time, although the increased weight cut range and endurance and conditions for some crew were cramped and at times quite hot, especially in the tropics at low level.

SP2H Neptune crews thus had mixed feelings about their aircraft. Pilots found it enjoyable and responsive to fly and despite its faults everyone appreciated how well it did the job in its early years. But however it was seen, by 1978 the SP2H was definitely showing its age and its belated replacement by the much more comfortable and capable P3C, and relocation of the squadron to Edinburgh to form 92 Wing, ended the Neptune era for the RAAF.