Learning topsy turvy.

In recent years the US services have introduced new basic ('primary' in Pentagon-speak) turboprop and advanced jet trainers based an European designs. Russia and a number of West European nations are now developing aircraft that will leapfrog these American derivatives. Meanwhile, Brazil is taking action to maintain its share of the market, and South Korea is about to discover whether its training aircraft can repeat the success of its automobiles.

In every category of fixed-wing trainer (i.e. primary, basic and advanced), the trend is toward increased performance, in order to reduce the flight hours that the student needs to spend on the inevitably more expensive following stage. Manufacturers have evidently convinced (or deluded) themselves that air forces will believe marketing claims of reducing the overall cost of pilot training, despite the increased cost of the new aircraft. This approach ignores the traditional reluctance (or outright refusal) of military operators to change their training syllabi, and may therefore take some time to prevail.

Primary

In the primary trainer category, Slingsby, whose fixed-gear 194 kW piston-engined T67M-260 Firefly is widely used, is reportedly studying a development with a smaller, thinner wing and a 'glass' NVG-compatible cockpit. Such an aircraft might well appeal to a country such as Bahrain, where students are scheduled to progress (under a programme established with assistance from BAE Systems) directly from the Firefly to the latter's Hawk advanced jet trainer.

Well-established primary trainers such as the Firefly and the retractable-gear Aermacchi SF-260 and Grob G120A remain available. The upper end of the piston-engined trainer spectrum has for decades been dominated by Yakovlev, over 1800 examples of the 270 kW Yak-52 having been built in Romania by Aerostar. The Russian Air Force has decided in principle to replace the Yak-52 with the 313 kW Sukhoi Su-49, developed from that company's highly successful Su-19 and Su-26 aerobatic aircraft. The Su-49, which will have a glass cockpit and Zvezda ejection seats, is to take students directly to the Yak-130 advanced jet trainer. In the interim there is talk of upgrading 50 or more of Russia's Yak-52s to Yak-52M standard, with new avionics, a stronger wing, increased fuel and a three-blade propeller. The Yak-52M made its debut at Maks 2003.

Yakovlev claims that there is interest from China in Hongdu licence manufacturing the projected Yak-152 that lost to the Su-49 in Russia, and that the Ukraine is planning a training system based on the Yak-152 and Yak-130.

Avtur (Aviation Turbine fuel)-burning diesel engines are finally making inroads into the general aviation field and it is possible that they will eventually be adopted as retrofits for primary trainers such as the Eads/Socata Epsilon. Many air forces would like to end their use of avgas, though progress in this direction appears to be glacial.

Turboprops

The most powerful piston engines overlap with the lower end of the turboprop range, but for a given power the latter are far more expensive. Past experience suggests that there is little demand for low-powered (250 to 350 kW) turboprop trainers.

Following slow sales of the SF-260TR Aermacchi has acquired rights to the much larger and better powered Valmet (later Patria Industries) L-90TP RediGO, which is marketed as the M-290TP. Both aircraft use the Rolls-Royce 250 series turboprop, which also powers Chile's Enaer T-35DT conversion of the piston-engined (tandem-seat) Pillan. The M-290TP RediGO is the best aircraft in this category in terms of operational flexibility, seating up to four in the liaison role, and having six hardpoints for loads totally 800 kg.

The main demand is for turboprop trainers in the 400 to 1200 kW class, a category that was largely pioneered by Pilatus, who began in 1966 by converting a piston-engined (194 kW) P-3. At the lower end of the range this Swiss company has sold 474 of the 410 kW PC-7s to 20 air forces, and 73 examples of the 520 kW PC7 Mk IIMs, likewise powered by the Pratt & Whitney Canada PT6A series.

Brazil's Embraer EMB-312 Tucano was the first trainer developed from the outset around a turboprop engine, a 560 kW version of the PT6A. Designed to accommodate ejection seats, it was 35 per cent heavier than the PC-7 but was only marginally faster, with no advantage in climb rate. Over 620 Tucanos were sold to 15 air forces (these numbers including the Shorts-built, Honeywell-engined version).

Pilatus responded to the Tucano with the PC-9, with a 708 kW PT6A, stepped cockpits and ejection seats. In its heyday this was the finest basic trainer extant, and it won the Pentagon's Jpats (Joint Primary Aircraft Training System) contest, providing the basis for the Raytheon T-6 (discussed later). Pilatus cites sales of over 258 PC-9s and pc-9Ms to 14 nations, including Australia, whose military aircraft selection processes are widely respected. Six PC-9Ms were recently delivered to Bulgaria.

The Korea Aerospace Industries (KAI) KT-I appears to be broadly corn parable to the PC-9M, having the same 708 kW PT6A-62A, but it is slightly heavier and has a higher wing loading. The first of five prototypes flew in December 1991, and deliveries of 85 to the Republic of Korea Air Force began in November 2000, replacing the T-37. This batch has now been completed, as has an order for seven KT-1Bs for Indonesia (with 13 more on option). KAI has offered the KT-1 to Turkey, which needs 60 basic trainers to replace the T-34B/C.

The Korean Air Force also requires up to 40 Fac/Coin aircraft to replace its 0-2s. In this context KAI has recently unveiled its KO-1, an armed derivative of the KT-1 with a mix of Elbit, Flight Visions (now CMC Flight Visions) and Thales avionics. The company is also developing an Enhanced Trainer designated XKT-1C, with armament provisions and the latest avionics and systems, including a full glass cockpit, obogs and single-point refuelling.

To compete in Jpats, Embraer developed the EMB-314 Super Tucano, with a stretched fuselage, a pressurised cockpit and a 970 kW PT6A-68A. The first of two prototypes flew in May 1993. In 1995 Embraer received a contract from the Brazilian Air Force (Forca Aerea Brazileira) to further develop the design to meet its ALX requirement, to fulfil the light attack role in addition to basic flight training. Converted from an EMB-314, the EMB-314M first flew in May 1996, powered by an 1195 kW PT6A-68B engine. The first new-build ALX flew in June 1999.

The ALX has a clean gross weight of 3290 kg and a maximum speed of 593 km/hr. It has Elbit avionics and NVG-compatible cockpit lighting. Five hardpoints can carry a total load of 1500 kg, in addition to which two 12.7 mm guns are fitted inside the wings (the first of its kind since the Korean War). The design is also unusual in having cockpit armour and in being produced (like the old Aermacchi MB-326) in both single- and two-seat forms. The single-seater is identical to the twin except for the simple removal of the rear to the benefit of an extra 350 litres of fuel.

In August 2001 the Brazilian Air Force ordered 25 ALXs as single-seat A-29s and 51 as two-seat AT-29s, with options on 23 more A-29s. The intention was to use the single-seaters for daytime 'policing' of the Amazon region in which a mix of guerrillas from neighbouring countries and drug, illegal mining and logging cartels settle in almost total impunity (Brazil has an 8000 km border with eight countries). The two-seaters are for night time operations and basic flight training. Deliveries to the Forqa A6rea began in December 2003 and is scheduled for completion in September 2006. The aircraft is marketed as the Super Tucano.

The Raytheon T-6A Texan II differs from the PC-9M in having a pressurised cockpit that accommodates a wider range of pilot weights and heights, single-point refuelling, Martin-Baker zero-zero seats, a Raytheon-patented rudder trim device, and a windscreen designed to resist a 1.8 kg bird impacting at 500 km/hr. In addition, the PT6A power management system is modified to produce a slower turbofan-like response. Clean gross weight is 2955 kg, and maximum speed is 575 km/hr.

The T-6A first flew in July 1998, and deliveries to the US Air Force began in 2000. The Pentagon plans to buy 782 T-6As by 2017, with 454 for the US Air Force and 328 for the US Navy, although the latter has delayed its introduction until 2007. The T-6 has also been adopted by Greece (45) and for Nato Flying Training in Canada (26). Annual domestic procurement is running at 54 units with exports currently boosting production rate to around 70.

Last year Raytheon launched its T-6B programme, with armaments clearance and improved cockpit displays. Unveiled at Farnborough, the T-6B prototype began an extensive marketing tour in January, prior to appearing at the Paris Air Show.

Pilatus decided to leapfrog the T-6 by developing from scratch the perfect basic trainer. Based on the company's unparalleled experience in this field, the new PC-21 (see title picture, courtesy of Pilatus) is to combine higher performance with life-cycle costs similar to those of existing turboprops and design emphasis is on mission management training.

The PC-21's increased performance was obtained by use of an 1195 kW PT6A-68B turning a five-blade graphite propeller, and a high wing loading. Stalling speed was restricted by large Fowler flaps, the consequently small (hydraulically-powered) ailerons being augmented by spoilers. The PC-21 has a pressurized cockpit, widened to accommodate three 6 x 8-inch displays. It has the latest Martin-Baker zero-zero ejection seats and inertial navigation coupled to GPS. An automatic yaw-compensation system minimises torque effects. The PC-21 has 25 per cent more fuel than a PC9M, allowing two training sorties without refuelling. The wing has five hardpoints for external loads totalling 1150 kg. Clean take-off weight is 3100 kg and maximum speed is over 600 km/hr.

The PC-21 programme was launched in early 1999, and the first of two prototypes had its maiden flight in July 2002. Full certification is scheduled for the end of 2006. One of its marketing targets is Britain, to replace the Royal Air Force Tucano. The Swiss Air Force is reportedly considering the PC-21 as a possible replacement for both the PC-7 and F-5B, taking pilots directly to the F/A-18.

Turbofans

Although those companies producing turboprop trainers have gone a long way toward eliminating propeller torque effects and easing the transition to jets, some involved in basic trainers argue that the higher cost of turbofan power is justifiable.

However, the demand for such aircraft appears to be limited. For example, China's Hongdu K-8, exported with a 16.5-kN Honeywell TFE731turbofan, serves in only small numbers in Egypt, Myanmar, Pakistan and Zambia. Egypt will reportedly manufacture 70 under licence, but Pakistan is said to have abandoned such plans. The domestic K-8J version has the old 16.9 kN Ivchenko/Progress AI-25TL, but the Pakistani Air Force is allegedly unenthusiastic about large-scale procurement of the aircraft.

The latest newcomer to this class is the Hindustan Aeronautics (Hal) HJT-36 Sitara. This is currently flying with a 14.2 kN GRTS Larzac, although production aircraft are intended to have the all-new 21.6 kN NPO Saturn AL-55. The first of two prototypes had its maiden flight in March 2003. The Indian Air Force has ordered a preliminary batch of 16, but the potential domestic market (including the needs of the Indian Navy) is estimated at over 200 aircraft.

The Aermacchi (formerly Siai-Marchetti) S-211 first flew in 1981, powered by an 11.15 kN P&WC JT15D turbofan. However, it did not fit in with Italian Air Force plans so only 58 were sold, mainly to Singapore. Despite this inauspicious background, Aermacchi feels that an improved S-211 will be able to compete with turboprops such as the Super Tucano and the PC-21. The new M-311 is described as having a 30 per cent more powerful engine, modernised cockpit and avionics and some structural modifications. Five hardpoints can carry loads totalling 1000 kg. The first M-311 was due to fly in May in the form of the modified S-211 Jpats demonstrator.

Advanced Trainers

The most successful of the current generation of advanced jet trainers is the BAE Systems Hawk, which benefits considerably from the endorsement of the US Navy and the ability of the company to arrange large-scale offset deals. Around 650 Hawks have been ordered, and the company also has a significant share in airframe production for the Boeing T-45 Goshawk derivative, of which the USN plans to acquire approximately 234. Hawks are also used in the six-nation Nato Flying Training in Canada (NFTC) programme and deliveries have begun to South Africa of the latest version with the 29 kN Rolls-Royce Adour 951.

The recent British decision to buy 20 improved Hawks for delivery from 2008 (with an option on 24 more) has ensured continuing production and encouraged India to buy 66; of which 42 will be built by Hal. BAE expects to sell around 400 more Hawks over the next 15 years. Despite India's acquisition of Hawks, in late 2004 Hal proposed the development of a new-generation Advanced Jet Trainer (AJT), based on the use of two uprated Larzac engines and a further development of the HJT-36 wing. Hal estimates a unit cost of around $ 20 million based on an order for 100 AJTs.

Aiming to recover its earlier dominance of the jet trainer market without bearing the full cost of developing a completely new advanced trainer, Aermacchi worked for several years with Yakovlev on the Yak-130. This offered flying training more representative of new generation fighters through a high thrust/weight ratio and high angle of attack capability. It also introduced the prospect of a programmable flight control system to prepare pilots for a variety of operational aircraft.

In 1999 this joint programme ended and Aermacchi developed its own derivative, the M-346, powered by two 28 kN Honeywell F124-GA-200 turbofans. It is aimed at the multi-national Eurotraining project, which is proposed to start in 2010. The first of three M-346 prototypes flew in July 2004 and on 7 March 2005 one of these performed its first flight with a dual full authority digital engine control. Aermacchi hopes to win support from other prospective Eurotraining nations, and a preliminary agreement on the M-346 has been signed with Greece.

The principal European alternative to the M-346 is the Mach 1.3 Eads Mako, but this is unlikely to fly before 2008. The Mako would be powered by a General Electric F414 derated to 75 kN. It is argued that, although it would be around 15 per cent more expensive than a twin-engined subsonic trainer (naming no names), the overall cost of jet pilot training would be reduced by 20 to 30 per cent, due to the shortening of the following phase.

However, a supersonic trainer already exists in the form of the T-50 Golden Eagle, which is being developed and marketed by Korea Aerospace Industries (KAI) with assistance from Lockheed Martin. Powered by a 78.5 kN General Electric F404, the first of three prototypes flew in August 2002. Plans call for development to be completed by the end of 2005 with deliveries beginning in 2006. The Republic of Korea Air Force has a requirement for 94, of which 25 are already on order. KAI hopes to export 600 T-50s over a 20-year period, but the scale of its success clearly depends on the US Air Force bringing forward replacement of the T-38.

China has its own supersonic trainer programme, which is evidently preferred to the low-speed K-8. This may eventuate as the Hongdu L-15, equipped with two Progress AI-222 engines. Yakovlev states that it has been co-operating with the AVIC-2 consortium on the L-15, which is in competition with AVIC-I's FTC-2000 (MiG-21 derivative). Unveiled at the Air Show China of 2004, the L-15 closely resembles the Yak-130. The first of three prototypes is scheduled to be flying by the end of 2005.

The subsonic Yak-130 was selected by the Russian Air Force in March 2002 in preference to the MiG-AT. The first of a batch of four production Yak-130s had its maiden flight in November 2003. It was equipped with two 21.6 kN Slovakian PS DV-2S engines, although the next three and others for domestic use will have 24.5 kN Progress AI-222s. Export customers have the option of the DV-2S. The domestic market is expected to represent at least 200 aircraft. Yakovlev is studying several variants of the Yak-130, including a carrier-capable trainer and a single-seat combat aircraft.