The US Army has awarded Boeing a contract which could form the first element of a comprehensive upgrade to keep the AH-64 Apache competitive well into the 21st century. The company is to undertake a four-year, $15.9 million, project to design, build and flight test a composite centre-section fuselage for the combat helicopter.

Boeing is reticent about discussing the full upgrade potential as it does not wish to distract from the battle to fund multi-year procurement for the remanufacture of the US Army's remaining AH-64As to the AH-64D Longbow configuration. The company says, however, that the effort is aimed at "-improvements for the Apache in the next century, when it will need to carry more weight, more systems and more weapons".

The fuselage award was made by the US Army Aviation Applied Technology Directorate at Fort Eustis, Virginia, under the Rotary Wing Structures Technology demonstration programme. Other contracts linked to the initiative have been awarded by the US Defense Advanced Research Projects Agency (DARPA) under the Technology Re-investment Programme.

One of the major DARPA contracts, called "Drive Train 2000", is for a new face gear/split torque transmission intended to go well beyond the current torque limit of the present spiral bevel gear system. The new transmission is designed as a drop-in replacement for the current unit and effectively splits the torque load between two sets of gears, allowing the gearbox assembly to be only one-quarter of the weight. "Slow roll" tests of the new 3,350kW (4,500shp) transmission are expected to take place within the next few months to demonstrate torque limits well beyond that of the current 2,100kW-limited AH-64 system.

Other elements of the effort, which Boeing describes as "-pieces of a puzzle that are not going to come together quickly", include a possible five-blade rotor with swept tips and an advanced new generation turboshaft engine. This will be evolved from the planned Joint Turbine Advanced Gas Generator Phase III demonstrator being produced as part of the US Integrated High Performance Turbine Engine Technology programme. Compared to the current General Electric T700, the Phase III powerplant is expected to have up to 120% higher power-to-weight ratio, a 40% lower specific fuel consumption and up to 35% lower production and maintenance costs.

Boeing says the advanced composite fuselage section will extend from the aft cockpit to just behind the engines and will be lighter, stronger and easier to manufacture than an all-metal structure.

The effort parallels similar work on changing the tailboom of the Boeing/Sikorsky RAH-66 Comanche to composite material.

Source: Flight International