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T-6 TEXAN II READY FOR SERVICE SOON

The fact that out of seven candidates a turboprop was chosen as the new standard training aircraft for the US Air Force and Navy came as a surprise to many. Cessna and Rockwell especially found it hard to believe and lodged a protest with the General Accounting Office. However, it was confirmed that everything had been above board during the heated competition over the Joint Primary Aircraft Training System.

"Our aircraft was the only one to fulfil all training demands without having to be modified. Apart from this we definitely had the better start as far as manufacturing and quality control is concerned," reminisces David Riemer, Vice President at Raytheon for the trainer program. "We weren't the cheapest, but we offered the best value for money." The company, which until recently was better known under the name of Beech, can boast a lot of experience with trainer aircraft. They had placed their bets on the best horse and had also "reacted professionally to any request put to them by customers ".

According to company studies it was obvious that a turboprop was the best, because it was the cheapest model for basic training. This became apparent as early as the end of the 80s. These aircraft are easily controlled by a beginner and can cover a wide performance spectrum. The Navy's Beech T-34C and the US Air Force's Cessna T-37 had to be replaced. Pupils move from these models on to high performance jets like the T-38 Talon or T-45 Goshawk.

Since JPATS competitors had to foot the bill for development costs, using existing models seemed the next logical step. According to Raytheons experts the PC-9 from Pilatus offered an ideal base: it was not too expensive, simple to build and performed very well. It also has excellent flight characteristics. In August 1990 a co-operation contract was signed with the Swiss manufacturer accordingly.

Since the middle of 1993 the role of the Swiss has been limited to collecting license fees. And even if the Beech MKII, which the aircraft was initially called, still shares the same outline with the initial model, this is where the similarities end. With the aid of computer design program CATIA Raytheon engineers have tailored the PC-9 step by step to the demands of the US Forces.

Most time was spent optimising the cockpit. In order to suit as many applicants as possible, (including females), the trainer, now known as the T-6 Texan II, needs to be flown safely by persons weighing between 52 and 111kg, measuring a height of between 1.5 to 1.9 meters. Many anthropometric studies were necessary to ensure satisfactory visibility, good placing of switches and the possibility of adjusting the ejection seat accordingly.

Martin-Baker was extremely busy in trying to prepare his Mk US16LA for the wide weight spectrum. Last year amongst others six sled tests were carried out with the US Navy in China Lake, California. The result was very satisfying in the complete range from zero to 370 KIAS, (666km/h) speed and zero to 35,000ft altitude.

Before ejection the canopy does not have to be jettisoned. The 20mm thick glass dome is broken with the aid of a detonaton cord. If this should fail, a thorn will crack the dome, which has an extremely thick front screen: Should birds weighing 1.8kg collide with it at a speed of 270kts, the aircraft will not be damaged.

The back seat is slightly raised to give the instructor a better view to the front. His instrument panel is identical to the trainee's and consists mainly of liquid crystal colour displays. However, they simulate mostly conventional displays, e.g. altitude, sink rate or engine parameters. The main advantage of the AlliedSignal and Smiths Industries equipment, which is interchangeable, is good reliability.

When compared with the PC-9, the cockpit of the Texan II is pressurised and air-conditioned. Especially T-37 users will notice and welcome this. There is also an innovation as far as oxygen supply is concerned: an OBOGS-System generates breathing air on board during flight and saves valuable time that would be needed on the ground for re-filling the oxygen tanks.

Instructors and trainees thus have an excellent work place. Handling of the Texan II will also convince them. Raytheon has spent a lot of effort on improving the flight characteristics of the PC-9, and to make the handling resemble that of a jet. Two systems have helped with achieving this.

On the one hand the T-6 received a so-called Trim Aid Device, a computer, which more or less eliminates torque and the gyroscopic effects of the propeller with automatic rudder inputs, by taking into account the speed, engine power and angle of attack. Trainees will have one task less to content with, which they will not come across once they are flying jets at a later stage.

The second important piece of equipment is the Power Management System for the Pratt & Whitney-Canada-PT6A-68 turboprop. Here it is also a computer, which ensures that the engine reacts quickly and linearly to power lever movements. According to Raytheon the computer is programmed to roughly correspond with a JT15D turbofan. Apart from this the Power Management prevents over revving of propeller and engine and makes automatic starts possible.

The crew need not fear inadequate power, since the deration from 1,274 to 820kW leaves plenty in reserve. It also has a positive effect on the life expectancy and maintenance intervals, which are predicted to reach 4,500 hours.

The airframe is also robust. The results of fatigue tests are not available yet, but Raytheon predicts 18,000 flight hours or 24 years active service. Prognoses have a firm foundation, because the structure of the T-6 is very conventionla, being built almost entirely of aluminium. Raytheon is convinced to be able to keep costs down by optimising work processes and using automatic rivet machines and milling parts, e.g. ribs.

$11.5 million were invested in a new hangar at their own airport in Wichita. Development, management and initial flight activities will be carried out here. Assembly facilities allow for up to 100 aircraft to be built during normal two shift operations per year. This will give enough space to fulfil export orders as well as supplying the USAF and the US Navy.

During a recent visit of by FLUG REVUE around a dozen T-6s at different stages of completion could be seen in the hangar or were waiting to be taken out for flight tests. Before the first Texan II will be handed over to the US Air Force "sometime in the first half of this year", certification by the FAA according to FAR 23 has to take place.

Schedules have been adapted a few times, but are still months late. According to a recent report of the Pentagon Director for Deployment Trials and Testing new problems only cropped up during later stages of tests. Among these is the icing over of the canopy, unsatisfactory cooling of the cockpit, an over sensitive nosewheel steering and incompatible safety harnesses for the pilots. The FAA also had reservations about quality control, which led to an interruption of ongoing tests last September lasting three weeks.

Taking all this into account, one hardly expects troop trials at the Randolph AFB in Texas, which have been scheduled for April to August, to be completed on time. Overall these delays may not be too alarming though, because the Pentagon has as yet only ordered 47 aircraft in small lots. It will not come as a surprise that the manufacturing of the planned 372 Texan II planes for the USAF and the 339 models for the US Navy will take until 2014. The entire contract amounts to $3.948 bn.

Additionally there will be a few billion for the ground based training systems like simulators, computer based theory training and last but not least, comprehensive utilisation management. Raytheon has chosen to subcontract Flight Safety Services after putting the contract out to tender.

The home-market alone provides a good turnover and brings 1,000 jobs to Wichita. A solid base like this gives Raytheon every chance to successfully market the Texan II internationally. Bombardier Services has already ordered 24 aircraft for its NATO Flying Training in Canada. Furthermore a contract with Greece is expected to be signed within the next few months. Chile has also expressed a need for 16 to 25 aircraft.

All in all Raytheon expects to build 1,000 Texan II - a number which no other trainer can boast within the last few decades. The new T-6 is therefore a worthy successor of the legendary North American Texan, on which tens of thousands of allied pilots were trained in the 1940s.

From page 54 of FLUG REVUE 5/99