Topic #: N03-020
Sponsor: NAVAIR PMA 275
Status: In Phase II.
Need: Rotary-wing aircraft transmission systems comprise up to 11 percent of the aircraft empty weight. Newer, more advanced materials and designs are required to achieve significant gains in power/weight ratio, durability, reliability,and maintainability.
Operational Gap: Weight of components composed of traditional materials has been optimized. Alternative materials are being sought to improve weight savings without sacrificing performance.
Specifications: The final component must meet requirements for weight reduction, cost, hot/wet mechanical properties, RTM processibility, fatigue resistance and chemical resistance.
TRI/Austin, Inc. is teaming with Bell Textron to develop composite transmission components to improve the range and lift capabilities of the V-22 Osprey. Phase II incorporates testing to achieve TRL 6 for the lube filter bowl. The company seeks PMA-275 program office support through qualification, logistics and documentation changes. The company also seeks program offices and primes needing lightweight composite components for Joint Heavy Lift Aircraft and other helicopter platforms.
Rotary-wing aircraft use transmission systems to transfer power from the engines to the rotor system. These transmissions employ lightweight high strength metals to reduce overall aircraft weight. Despite the optimization of these materials for weight, these transmission systems still comprise up to 11 percent of the aircraft empty weight. The Navy and the helicopter industry would like to further decrease aircraft weight, as an increase in performance can be achieved for every pound of weight reduction. The Navy solicitation for this topic seeks significant gains in power/weight ratio, durability, reliability, and maintainability. It also states that, “gearbox housings currently have a high scrap rate due to corrosion induced by the Navy’s harsh operational environment. Advanced corrosion-resistant materials would provide substantial cost benefits by reducing the rejection rate of these components. The proper material selection could also provide a substantial weight savings.”
Composites offer advantages over metals in that they resist corrosion and can achieve equal or higher strengths with less weight . The Bell V-22 tiltrotor uses higher power density transmissions than those used in conventional helicopters. Presently, commercially available carbon/epoxy composite systems have low thermal conductivity properties. The lube filter bowl was chosen as an initial candidate to mitigate the effect of low thermal conductivity on the heat rejection of the gearbox. Technical success in this component will translate to other composite components aboard the aircraft.
Texas Research Institute Austin, Inc., with teaming partner Bell Helicopter Textron, Inc. is developing lightweight composite material systems that will meet design requirements to be used in a military rotorcraft transmission environment.