Profile – GAF Nomad

Project N1 was originally proposed as a utility aircraft for military use, but GAF saw that the aircraft had promising civil applications. The N1 had STOL capabilities and was designed with a unique lateral control system with cross-linkage now seen in the Nomad. Although it was planned to power the N1 with a turboprop from either United Aircraft of Canada, Turbomeca or Garret-Airesearch;, the Airesearch TPE 332 was chosen for performance calculations. This engine would have given the N1 a cruise speed of up to 200 mph, and an ISA sea level take-off run of just 90 feet empty or 360 feet fully loaded. In the military configuration, eleven fully equipped troops or up to one and a half tons of freight could be accommodated.

The N1 was also seen as an answer to the requirement for an agricultural aircraft with a fast-spreading rate, and the N1 design was modified to facilitate a 70 cu ft hopper in the centre fuselage, and the cockpit raised by 10 inches to protect the pilot from the hopper should it move forward in a crash. It was estimated that a 20 to 25% reduction of direct operating costs could be achieved over the DHC Beaver, then the most effective of locally available agricultural aircraft, although the N1 would have had a higher initial cost. The N1 design was scrapped before full development, and gave way to the N2 design in 1967, when the Army changed the requirement for what they called ‘twin-engine reliability’. A Joint Air Staff Requirement AIR-68 followed, which defined four major roles for the aircraft in RAAF and Army service: Forward area mission, forward air control, battlefield surveillance, and command and liaison.

The N2 project, under the direction of Alan Wrigley, was developed with a box-sectioned cabin layout, with side-by-side cockpit seating. The FAC version was to have tandem configuration, but interest waned before this sub-type reached any more than the initial design stage. It was decided to power the aircraft with the Allison 250 turboprop – the first fixed-wing application of this engine which was powering helicopters like the JetRanger and Hughes 500. The N2 inherited the STOL characteristics and lateral control systems of the N1 and incorporated a fully flying tail and retractable undercarriage. In January 1970, the Commonwealth Government approved the funding for the construction of two N2 prototypes and a static test specimen.

The first prototype was constructed at GAF’s Port Melbourne factory, and after completion was taxied at Port Melbourne before being transported to Avalon for flight testing. On the 23rd of July 1971, the aircraft registered VH-SUP, made its maiden flight. The wheel pods had been removed for the first flight. The second prototype, registered VH-SUR, made its first flight at Avalon on 5th December 1971. Both these aircraft flew with a nominal gross weight of 7000 lbs (3174 kg), which was increased to 8000 lbs (3629 kg) early in the flight test programme. The first N2 prototype was configured with a full-length rudder, which was shortened soon after its first flight and the fin area increased by the addition of a leading edge fairing. It was also decided to alter the undercarriage design which, in the N2, consisted of single wheel main legs retracting through sideways opening doors into the wheel pod, and a single rearward retracting nose wheel with one sideways and one rearward closing doors. The production aircraft were to be fitted with dual main wheel legs retracting forward into the wheel pod with a single rearward closing flipper door, and a rearward retracting nosewheel with two sideways closing doors. The 13-seat production version of the aircraft was to be designated N22.

In June 1972, Government approval was given of twenty N22 aircraft, to be named “Nomad”. Eleven of these aircraft were to be allocated to the Australian Army Aviation Corps. In August 1972, the N2 prototypes were granted DoT-type certification. The N22 production began, with component and sub-assembly at Port Melbourne and final assembly at Avalon. The first production N22 aircraft were fitted with the Allison 250-817 engine, but later production aircraft were fitted with the uprated 250-8178. With the new engine and other modifications including an increase in gross weight to 8500 lbs (3855 kg), the production version became known as the N22B. The second N2 prototype, VH-SUR, had, during its test flying, suffered a two-engine failure due to icing, and had force landed on a road with subsequent heavy damage, and was removed from service.

The first production Nomad flew on 3rd October 1974. At this stage, the first stretched Nomad derivative was well underway; and was to become known as the N24. The N24 featured a 3 ft 9 in (1. 14 m) fuselage plug and a 2 ft 1 ½ in (0. 65 m) longer nose fairing, allowing 17 passengers to be carried. Increases in gross weight to 9200 lbs (4,173 kg) and then 9400 lbs (4265 kg) were soon achieved, and with these new weights the production stretched Nomad was designated N24A.

In May 1975, The N22 received its DoT-type certification, followed in May 1977 by its American FAA certification to FAR 23. (Certification to FAR 135 Appendix A followed in December 1978. ) Production of fifty more Nomads had been authorised by the Government in 1973, and by 1975 sixteen aircraft were flying, and by 1976, thirty-six Nomads were in the air. Later in 1976, Government approval for an additional 25 aircraft was granted.

1976 was a tragic year for the Nomad. Two fatal accidents did nothing to enhance the aircraft’s reputation. In June, an N22 of Sabah Air (Malaysia) carrying Sabah’s Prime Minister and ten members of his cabinet, had been approaching the main city of Kota Kinabalu in light rain when the aircraft spun into shallow sea, killing all its occupants. The aircraft had been incorrectly balanced and overloaded. Two months later, at Avalon, the N24 prototype took off to carry out tests with full-span trim tabs with trailing edge T-strips fitted to the tailplane. Shortly after take-off, at 950 feet, a flutter of the tailplane and trim tabs occurred, and the aircraft crashed into the ground after sustaining structural damage causing loss of control. Tragically, the test pilot and observer suffered fatal injuries, and the third occupant, the flight test engineer, was severely injured.

Sales of the Nomad continued to grow slowly but steadily, and GAF began offering the aircraft in different configurations to suit individual customers. The military version of the Nomad was dubbed “Mission Master”, a name that did not stick, and other “Master” names were adopted for specialist aircraft: Medic Master, Survey Master, Float Master and Search Master.

Medic Master was the name coined for the air ambulance version of the Nomad, and Survey Master was chosen for two N22Bs operated by Austirex in Western Australia for mineral survey work, and distinctive by its magnetometer boom. Float Master refers to a series of floatplane and amphibian conversions made by Wipaire Incorporated of Minnesota USA. Interestingly, none of the Float Master conversions has ever found its way back to Australia, and operation of the type is restricted to North America.

The Search Master version is one of the more successful applications of the Nomad. Two Search Master derivatives, the Bravo and the Lima, were introduced in an attempt to break into the coastal surveillance market. The Bravo was fitted with a Bendix RDR 1400 120° search radar. The Searchmaster Lima was equipped with a Litton APS-504(V)2 360° search radar mounted in a chin radome and operates at an increased gross weight of 9100 lbs (4128 kg). Other Search Master modifications included the floor drop hatch of the Mission Master, observer bubble windows, extended fuel capacity to increase endurance, and fitment of the Omega navigation system. The Indonesian Navy was the first Search Master B customer, taking delivery of the first of sixteen in December 1978. The Search Master Lima versions were acquired by a number of operators who successfully tendered for surveillance operations on behalf of the Customs and Transport Departments, the main initial operators being Executive Airlines, Northern Airlines and BPA. All Search Master derivatives were designated N22S.

South Africa and India were two countries that investigated the possibility of licence manufacture of the Nomad, but both proposals never eventuated.

The decision to go ahead with the Australian Basic Trainer and the local production of the F-18 Hornet had disastrous effects on the Nomad project. It was foreseen that there would be a workload capacity problem at GAF, and some optimistic prophets predicted that the entire Nomad project would be passed on to private enterprise, but in reality, the writing was on the wall for Nomad. In 1982, the Government announced that the production line would be closed at 170. A T-tail which was to be introduced onto the Nomad was cancelled with the project. It then became apparent that GAF would have difficulty in selling the remaining aircraft, as customers are difficult to find for an aircraft at the end of a production line. It is even now possible that production may close down earlier than 170. The resale value of the Nomad subsequently crashed, with two N22Bs recently offered for sale at around $100,000.

Operation

The Nomad has been operated in a variety of roles, and in countries throughout the world. New Guinea was one of the first users of the Nomad, with Douglas purchasing one N22 and three N22Bs, and Provincial Air Services purchasing two N22Bs, while the Papua New Guinea Defence Force acquired three N22Bs. Military users, apart from Australia and New Guinea, are the Philippines(twelve N22Bs), the Indonesian Navy (sixteen Search Master Bs and two Search Master Ls), and the Royal Thai Air Force – a relatively recent customer (twenty N22Bs). The Northern Territory Medical Service was the first N24 operator, acquiring seven of the type. The NSW Flying Doctor Service purchased two N22Bs, which were then the most comprehensively equipped flying doctor aircraft in service. The Nomad is or has been in civil service in Malaysia, Japan, New Zealand, Chile, Guam, Marshall Islands, Surinam, Switzerland, Norway and the United States. However, the Nomad never really won the popularity it deserved as a commuter line in Australia, although the type has been operated by a number of airlines including Nationwide, Clubair, Bush Pilots Airways, Skywest and Pagas Airlines.

Technical Description

The Nomad is an all-metal high-wing monoplane powered by two turboprop engines with fully feathering propellers. Reverse thrust is available for aerodynamic braking on the ground. A fully retractable tricycle undercarriage is incorporated. An optional manual cargo floor hatch is available. Baggage compartments are provided in the nose forward of the flight compartment and at the rear of the main cabin. At one stage a hinged tail version of the aircraft was planned, but apart from modifications to VHSUP, the cost was found to be too prohibitive to fit to production aircraft.

The wing is braced to the fuselage by single extruded lift struts attaching each side at the undercarriage stub wing. The two spars in the wing are stiffened webs with ‘L’ section machined extrusion spar caps, and the skins are stabilised by ‘Z’ section stringers. The fuselage is a conventional light alloy semi-monocoque structure.

The two Allison 250-817B engines each develop 400 SHP, and incorporate an air bleed system for engine fuel control, and oil system for engine lubrication and propeller control, and an electrical ignition and starting system, and sensors for monitoring engine performance. Fuel is stored in four wing tanks in the basic version, each of 250 litres capacity.

There is no hydraulic or pneumatic system, and the flaps and undercarriage services are electrically operated. The electrical system comprises a DC power system and an AC power system, of 30V and 115V respectively. The 26V 22Ah battery is housed in the port wheel pod.

Dual controls are fitted. All control surfaces are mass-balanced, and trim tabs are fitted to the rudder and horizontal stabilizer. The lateral control system is unique in that full-span double-slotted trailing edge flaps are fitted, the outboard rear sections of which operate as ailerons while the flaps are fully retracted. When the flaps are extended, lateral control is maintained by spoilers located on the outboard upper surface of each wing, progressively assuming lateral control from the ailerons/flaps as the flaps are extended.

Four separate anti-icing systems are provided; one system using engine bleed air, and the other three using electrical heater elements. The engine anti-icing system ducts hot bleed air from the compressor diffuser scroll to the compressor inlet and anti-icing shroud. Propeller anti-icing is achieved through cycling electrical output through a timer or two heater elements on the leading edge of each blade. Pilot and stall warning and windscreen anti-icing is also electrically operated.

A degree of criticism has been levelled against the Nomad in the past, some of it originating for political reasons, and other for technical reasons. The first barrage was a politically based criticism that the aircraft was being sold at a loss. To what degree this was the case is difficult to say, because GAF has a responsibility to maintain manpower and expertise levels, but it was mooted that GAF would begin to break even at the 200 mark. The virtual gift of Nomads to Indonesia under overseas aid agreements, and the debacle surrounding the Australian Army Nomads, were further sources for criticism of the project. It was said that the Indonesian and Army aircraft allocations were a case of the Government selling the aircraft to itself. The problem with the Army aircraft concerned the fact that the original Cessna 180 replacement requirement was met by the Pilatus Turbo-Porter, and the Army appeared to have no requirement for the Nomad. Further criticism surfaced when the RAAF’s Aircraft Research and Development Unit, who test-flew one of the Army aircraft (A18-303) for a number of years, released their report on the Nomad, which claimed that the aircraft was dangerous in some configurations. One of ARDU’s specific comments concerned the aircraft’s tendency to pitch up during full power full flap stalls. A microswitch normally retracts the flaps automatically on full power application. It must be pointed out that ARDU were evaluating the aircraft using military criteria, which are very different from civil criteria.

Other complaints about the Nomad centred around technical problems with the tailplane, microswitch circuits, cracked engine cowls, loss of engine,e cowls in flight, and burnt-out flap motors (see Australian Aviation Sept. 1980). Retrospective refits and recalls coped with the tailplane problems, and modifications were made to solve the others. Despite all the criticisms, however, most operators were happy with the aircraft, particularly so, ironically, the Army Aviation Corps. The Nomad was found to be able to be operated at low cost, and was satisfying to fly. The aircraft has outstanding short and rough field performance and good low-speed handling. Shortcomings included a tight centre of gravity envelope, poor single-engine performance, lack of seat adjustment fore and aft, and an only adequate amount of pitch control in the flare.

Conclusion

The Nomad project proved that Australia could achieve international sales with a locally designed aircraft, and kept aircraft manufacturing techniques in this country for well over a decade, bridging the gap between the Mirage and F-18 projects. Perhaps the demise of the Nomad ca be attributed to GAF never really being in control of the project; always waiting and waiting for Government approval to allow another 25 aircraft to be built. It was impossible for GAF to plan more than twenty-five aircraft or one year ahead of themselves, as the future of the project was always uncertain solely because it relied on the whims of Government department budgets. The Nomad created lots of firsts, and ought to be applauded accordingly. Lots of lessons were learnt and are to be learnt from Project N, which certainly makes the project a worthwhile venture.