HARS Aviation Museum
HARS Aviation Museum

Lockheed SP-2H (P2V-7) Neptune

Neptune 273

Four engine military maritime reconnaissance, patrol and anti-submarine aircraft


The Lockheed Neptune was the first aircraft designed for long range, maritime patrol, anti-submarine warfare tasks.  Whilst its development started shortly before Pearl Harbour, low development priority meant that its first flight did not happen until May 1945.  Prior to its appearance, aircraft designed for totally different tasks were assigned to this essential duty, aircraft such as the B-24 Liberator, which were designed to fly at high altitude away from the fatiguing low altitude turbulence that was needed for aircraft in this role.  It is salutary to remember that during its 19 year production life, the Neptune was developed and extended in capability beyond anything its initial designers had imagined.

When it first appeared, the Neptune was powered by two Curtis Wright R3350 engines of approximately 2300 hp.  Compared with its final form with two 3500 hp engines and two 3400 lb turbojets, it resembled the “bomber” style of thinking that was used at that time, with a number of defensive gun turrets.  History has a number of examples of the transition in thinking such as this – HMS Warrior is a perfect example.  HMS Warrior was the first steam powered warship of the Royal Navy, however despite many improvements, it still reflected the way of thinking of “sail warfare” of the time, with extensive defence against boarding parties in its equipment.  It wasn’t until they had the ship in service that they realised that it could just avoid such an event using its engines.

Gradually during its life, each model of the Neptune had reduced defensive armament until the P2V-5 during its service in the 1950s and 1960s  eventually lost all of it during mid-life modifications.  It was during these modifications that the Neptune gained its MAD boom (designed to detect metal under water owing to the distortions it causes in the Earth’s magnetic field) and its two auxiliary jet engines.

Aircraft Designations

As with other US Navy aircraft, there are two designation systems used for the Neptune.

  • The first is the Navy’s (obviously) which is the P2V followed by the version number.  P2 refers to Patrol Bomber, whilst in this case V is probably for “Vega” the Lockheed subsidiary that developed it.  In other contexts, V stands for “Heavier than Air”.  Under the Navy system we have seven variants, from P2V-1 to P2V-7.
  • In the early 1960s, aircraft designations were unified between the US Navy and the USAF, so the Neptune became the P-2 and aircraft in RAAF Service were then P-2E (P2V-5) and P2-H / SP-2H (P2V-7).

Australian Service

Australian involvement with the Neptune started in 1951 with the first orders for the P2V-5 for 11 Squadron, then based at Pearce in Western Australia.  The Squadron moved to Richmond, near Sydney and it was here that the only loss of a Neptune occurred.  On 4 February 1959, during an air-test A89-308 crashed near Richmond after an engine caught fire and eventually burned through the wing spar before the aircraft could land back at the base.  All crew were lost.  The outcome of this accident was that the next variant of the Neptune to be ordered by the RAAF had fire extinguishing systems installed, the only twelve of this aircraft type so fitted.  This can be seen on the Society’s ex-RAAF (10 Sqn) Neptune 273.  11 Squadron’s involvement with the Neptune ended in 1968 when they swapped their P2V-5 aircraft for the P3B and moved to Edinburgh in South Australia.

The first three P2V-7 aircraft arrive at RAAF Townsville in 1962 to replace the Avro Lincoln that 10 Squadron was previously equipped with.  You will notice that the HARS Neptune was one of those three to arrive.

In 1978 10 Squadron started re-equipping with the P-3C Orion and relocated to Edinburgh to join 11 Squadron.

The Westinghouse J34 Jet Engine

The two auxiliary jets hanging from the outboard wings are a common source of confusion, especially these days when this configuration is no longer seen.  During the 1950s, it was common for aircraft types as they were developed and modified, to become under-powered as their weight and capability increased.  The solution was often to fit one or two auxiliary jet engines to assist at critical times.  These engines were used for takeoff, climb and landing (they were set at idle during the landing approach so that in the event of a go-around they could be advanced to full power), both for better performance and in the event one of the piston engines should fail at a critical time.  Despite what many people think, they used the same Avgas fuel used by the piston engines, though a couple of disadvantages restricted the use of the jets.  Fuel consumption soared many times over using the jets so they were only used when they absolutely were needed in flight, such as for high speed sprints or if needed for short bursts in the event of engine failure to assist “drift-down” performance.  The high lead content of the fuel also restricted the amount of use, since lead built up on the turbine blades and would eventually damage the engines if not maintained properly.

There is a cut-away example of the J34 on display in the HARS Engine Hall.

Detection Equipment


A sonobuoy is a device about a meter long and 15cm in diameter that is deployed by ASW aircraft to float in the water and detect submarines, reporting the collected information back to the aircraft by radio.  Typically they deploy microphones or pingers up to a thousand meters below the surface.  They are typically either passive or active.

Jezebel is the name given to the US Navy’s first passive sonobuoy.  It was basically a microphone on a long wire, connected with a floating buoy that kept in radio contact with the ASW aircraft.  The name comes supposedly from Queen Jezebel from the Bible who “listened at keyholes” and betrayed others.

Julie was the name given to the US Navy’s first active sonobuoy, which had a “pinger” that then listened for replies of reflected sound.  It seems the buoy was given that code name because the development team frequented a popular “establishment” after hours where one Julie Gibson performed.  They named it “Julie” because “Julie makes passive buoys active”.

It was the fitting of the Jezebel / Julie sonobuoy system that earned the change of designation from P-2H to SP-2H.

Radar and EW

The large bulge under the forward fuselage contains the aircraft search radar.  It is capable of detecting surface contacts, even periscopes and has a secondary function as an aircraft tracking radar or AWACS.  This was used by No 10 Squadron with their Neptunes (SP2-H) during the Vietnam conflict when they operated out of Utapao in Thailand in support of USAF air operations.  They also used their Electronic Warfare suite to detect and if necessary jam enemy radars.

Searchlight, MAD, Diesel Sniffer

The Neptune has a 70 million candlepower searchlight on its right wing tank.  There is a glare shield to prevent it blinding the crew.  The searchlight can be aimed by either the nose observer or the co-pilot.  The other two devices are the MAD unit described previously which is contained in the extended tail “stinger” and a diesel fumes sniffer on the nose of the aircraft.  This is of less use these days since many submarines are nuclear powered and so do not leave an exhaust trail.


During the early part of its life, the Neptune was equipped with .50 cal machine guns, 20 mm cannon for defensive armament, however this was eventually removed.  Bombs, depth charges and torpedoes were its normal stock in trade.  The USN did equip some with Nuclear bombs at one time.

The Truculent Turtle

In September 1946, the US Navy flew (a modified) aircraft – the third production Neptune from Perth Western Australia to Columbus Ohio, just short of its intended destination of Washington.

History of A89-273 (VH-IOY) and 147566 (VH-LRR)

Both HARS aircraft are P2V-7 / SP2-H aircraft.  #273 was bought by the RAAF in 1962, and #566 by French Marine Escadrille in 1959.  #273 is relatively “young” aircraft in airframe terms with only ~5,500hrs.  #566 has done more work with more than 7,000 flying hours.

By the end of 2017, there will be only Four flyable Neptune aircraft in the World (two in the US and two in Australia).  HARS will be operating two of them. (any corrections to that will be gladly accepted).


P2V-7 Neptune A89-273 (later designated SP-2H) was built at Lockheed’s Burbank plant in California, USA. The manufacturers serial number was No. 7273. Bauer No. 149,073, being delivered to the RAAF and arriving in Townsville on the 10 March 1962.

It was allocated to 10 Squadron, which then operated out of Townsville, as an Anti-Submarine Reconnaissance aircraft, and was one of a total of 24 Neptunes operated by RAAF 10 and 11 Squadrons. It served with 10 Squadron from March 1962 until being retired from RAAF service in May 1977 when it was placed in storage at Townsville awaiting disposal. During its years of service A89-273 logged a total of 5476 flying hours.

Long after the aircraft was de-commissioned it was acquired from a private owner in Townsville by members of the Society, interestingly enough on 1st April 1988.

Since its total restoration over 10 years ago, this aircraft has been on the Air Show circuit thrilling audiences with an imaginative flying routine.  In November 1996, the Society commenced an extensive maintenance program on Neptune A89-273 from nose to tail, culminating in the aircraft being declared airworthy again in January 1998. All maintenance was carried out by our own engineering team.

In November 1999, the Society had great pride in returning 273 back to its old squadron at Edinburgh Air Force Base in South Australia to celebrate the 60th Anniversary of the formation of 10 Squadron in 1939. Edinburgh is now the home base for this squadron. Neptune A89-273 VH-IOY is the only former RAAF Lockheed Neptune flying in Australia and is maintained, operated and crewed by members of HARS who maintain a high degree of maintenance and safety, and continually strive to maintain the aircraft in immaculate condition. With large amounts of spare parts and engines available it is anticipated that Neptune A89-273 will continue to be maintained in a flying condition and appearing at air shows throughout Australia for many years to come.

Click the following link for …

A Virtual “Tour” through “273”


This is the second of of the two Lockheed Neptune P2V-7s operated by HARS.  Neptune 566 was one of 31 operated by the French armed forces from the late 1950s and was allocated to French Marine Escadrille 12.  The aircraft was eventually flown to the French Polynesian territorial island of Tahiti in the Pacific in 1983 and was stored at Papeete International Airport.

In 1987 a representative from HARS attended a conference held in Tahiti and contact was made with the French Embassy in respect to obtaining a French Neptune.  Upon arrival at Tahiti-FAAA (Papeete’s International Airport) three Neptunes were sighted, one partially burnt, one stripped of its engines and the other (147566) appeared to be intact.  These three aircraft were all that remained of Escardrille 12.  An inspection of Neptune 566 revealed that although some instruments were missing, the aircraft was in sound condition and its tanks still contained 2000 lbs of fuel.  The aircraft was located in an area that could easily be described as a swamp, into which it was slowly sinking.

The original intention was to acquire and dismantle the aircraft as a source of spare parts for the Society’s other Neptune (273), however after viewing the documentation, the decision was made to restore the aircraft to flying condition in Tahiti and fly it back to Australia.  It had flown more than 7,000 hours but was considered to be in excellent condition as the aircraft had been extensively overhauled just prior to being de-commissioned.

After further negotiations the title was transferred to HARS.  There were a number of trips to Tahiti before Neptune 566 was finally made ready by HARS members for the ferry flight to Australia in July 1989.  Neptune 566 was placed on the Australian civil register as VH-LRR, and after a number of public appearances at air shows, was positioned to Tamworth for storage and care.  In September 1999 the aircraft was ferried from Tamworth to Bankstown and then in January 2003 it was flown to the new HARS base at the Illawarra Regional Airport where the overhaul work continues pending return to full flying status.

HARS Neptune, Wollongong New South Wales

Notes from a Former French Navy Pilot of 566

Over the last couple of years, I’ve been privileged to have exchanged emails with a former pilot of 566.  I asked him to have a look over the Neptune information we had written here for his comments.  Rather than change anything, since for example the Neptune flight manual leaves the choice of starting the jets for landing as an optional step, I thought I’d post his comments here for more accurate information.


NO, we did not open the jet doors for normal landings with normally operating reciprocating engines for two main reasons :

  • The Neptune being a MPA, flown over the ocean and from Navy Air Stations close to the coast, we did not want to take the risk to ingest heavy sea-birds in an operative jet if not necessary (I saw it once !) ;
  • As we always used reverse thrust after landing we did not want to take the risk of ingesting FOD in a jet from objects thrown forward by propeller blast.

We only started the jets and idled them when landing the plane with one feathered reciprocating engine – in case of a go-around

  • Without jets with one engine inoperative, we had a decision height of 600 feet, above which we would dive to the ground to recover climbing speed, which was done close to 0 feet height or below 600 feet we had to land.
  • With the jets idling, we could go around in the single Piston engine case when reaching the minimas, close to 0 feet.

Over the sea :

  • We opened the doors below 500 feet and the jets were free-wheeling slightly over 10 %, ready to be ignited by opening the petrol and pushing the igniter buttons ;
  • We could also above that height start very quickly a jet by electrically starting it, doors closed, obviously nothing happened, then immidiately after beginning to open the doors, the electric starter engaged (doors security switches removed) and in a matter of seconds we were over 10 %, with ignition, and due to an excellent regulation could push directly to 100 %.

Fuel consumption

I remember these figures :

  • From engine start to wheels leaving the runway : 200 USG ;
  • Climb to FL100 : 100 more USG ;
  • Cruise on reciprocating engines (between 150 and 160 kts, reducing by 100 RPM each time we reached 160 kts) : 200 USG / hour ;
  • With both jets at 96 % : 1,200 USG / hour (used as the only petrol jettisoning procedure on the plane).

Diesel Sniffer

Already in the 70’s the sniffer had been rendered unusable due to the quantity of smoke spread over the oceans by cargo ships and tankers.

Life of 566

  • 566 was mostly assigned to the FLOTTILLE 23F and FLOTTILLE 25F (F for Flottille, a Squadron performing fighting missions) until the end of Neptune operations from continental France ;
  • 566 was then assigned to the ESCADRILLE 12S (S for Escadrille, a Squadron performing support missions).

According to the document I have enclosed :

  • 566 entered the active service on the 20th of May, 1959 ;
  • 566 had a first V4 visit (4th degree maintenance in civilian industrial facilities, the BREGUET AVIATION, which built also Atlantic 1 and Atlantique 2 MPA) from the 19th of January, 1966 to the 14th of September, 1966 ;
  • 566 had several V2 maintenance (2nd degree) in its Squadron Technical Service (roughly 2 months duration) ;
  • 566 had also several V3 maintenance (3rd degree performed by the Navy Air Station Technical Services – might reach 6 months duration) ;
  • 566 had a second and last V4 visit by Breguet Aviation from the 13th February, 1973 to the 17th of September, 1974 (total duration 20 months!) and came out of the facilities as new with 0 hours (actualley already 4389 – GM=4389.0). We used in the FN to consider that a plane coming out of a V4 had 0 hours airframe hours ;
  • 566 had an extended V3P from the 11th of September, 1981 to the 7th of April, 1982 ;
  • 566 was assigned to 12S in Tahiti on the 4th of July, 1983 ;
  • 566 was decommissionned on the 13th of August, 1984.

Total hours flown was 7,183 hours and 48 minutes, the second highest in the French Navy.

Technical Specifications

Piston engines: 2 x Wright R3350-32W Turbo Compound, 18 cylinders, 2 row, air-cooled, radial engines, ~3,700 bhp

Jet engines: 2 x 1,542 kg (3,400 lb) thrust Westinghouse J34-WE-36 jets

Maximum takeoff weight: 36,240 kg

Length: 27.7 m

Wing span: 31.4 m

Height: 8.5 m

Patrol speed: 280-330 km/h @ 1,000 ft (max ~590 km/h @ 10,000 ft)

Ceiling: 22,400 ft

Range: 3,500 km (6,000 km with bomb bay tanks)

Crew: 2 x pilots, Navigators/Bombardier, Radar/MAD Operator, Radio Operator, Sonobuoy Operator, Ordinance Operator (typically)

Armament: Up to 3,600 kg (bombs, torpedoes, depth charges, mines), 8 x under-wing rockets, Julie active echo sounding, Jezebel passive sonobuoy