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RTM process cuts fighter tail costs
processingnews
RTM process cuts fighter tail costs
The RThi process produces a high quality product cost saving.
AS PART OF its efforts to drive down production costs of aircraft complex composite components, Lockheed Martin Aeronautics Co says it has demonstrated a 60% reduction in manufacturing costs over previous designs by using an advanced resin transfer moulding (RTM) process to fabricate a tail structure for a fighter aircraft. The all-composite component is similar to the vertical tail of the Lockheed Martin Joint Strike Fighter fJSF) aircraft. Compared to traditional designs the tail structure was produced as a single component, reducing the part count from 13 to one, and eliminating more than 1000 fasteners. Lockheed Martin Aeronautics, based in Fort Worth, Texas, says the vertical tail is one of the largest and most complex composite components ever produced using RTM. It measures 3.6 m along the leading edge and weighs around 90 kg. The skins are made up of over 100 plies and vary in thickness by a factor of four from tail root to tip. Fourteen unique, complex
at a substantial
mandrels with continuously variable cross sections were over-braided to create the internal structure. As well as reducing manufacturing costs, component quality was improved. The project demonstrated that modelling of the resin flow can accurately identify preferred injection sites and sequences to ensure proper impregnation throughout the component. Using the optimum model prediction resulted in complete mould filling (no dry spots) and significant benefits to quality and production cost. Other members of the project team included the Air Force Research Laboratory and University of Dayton Research Institute, which helped with the modelling required to predict resin flow patterns during mould filling. Cytec Fiberite supplied the bismaleimide (BMI) resin and carbon fabric the component is made from and A&P Technology provided the complex, computer-controlled custom braiding over machined mandrels. North Coast Tool and Mold provided the
10 tonne steel and aluminium mould and the injection fixture. restraint Radius Engineering supplied the computer-controlled resin injection system. The RTM vertical tail project began at the end of 1998, one of many projects conducted under Lockheed Martin Aeronautics’ Advanced Affordability Initiative (AAI). AA1 was initiated in 1997 to demonstrate advanced material, designs and manufacturing technologies that will significantly reduce cost of aircraft components for the next generation of combat aircraft. “This RTM demonstration is a major step forward in advancing the producibility of
complex, composite aircraft components,” according to Kenneth Taylor, director of the AAI. “We are beginning to capitalize on the performance advantages of composite materials at costs that rival traditional metallic designs. These advances in composites are providing us confidence in our ability to affordably produce the next generation of fighters.” Lockheed Martin Aeronautics Co specialises in the development, production and support of military aircraft and related technologies. Its products include the F-22, F-16, X33 and Joint Strike Fighter. Mike Nipper, Lockheed Martin; tei: +I-81 7-777-4973; email: [email protected].
February 2001
RElfWDRCEDplastics
15
RTM process cuts fighter tail costs
The RThi process produces a high quality product cost saving.
AS PART OF its efforts to drive down production costs of aircraft complex composite components, Lockheed Martin Aeronautics Co says it has demonstrated a 60% reduction in manufacturing costs over previous designs by using an advanced resin transfer moulding (RTM) process to fabricate a tail structure for a fighter aircraft. The all-composite component is similar to the vertical tail of the Lockheed Martin Joint Strike Fighter fJSF) aircraft. Compared to traditional designs the tail structure was produced as a single component, reducing the part count from 13 to one, and eliminating more than 1000 fasteners. Lockheed Martin Aeronautics, based in Fort Worth, Texas, says the vertical tail is one of the largest and most complex composite components ever produced using RTM. It measures 3.6 m along the leading edge and weighs around 90 kg. The skins are made up of over 100 plies and vary in thickness by a factor of four from tail root to tip. Fourteen unique, complex
at a substantial
mandrels with continuously variable cross sections were over-braided to create the internal structure. As well as reducing manufacturing costs, component quality was improved. The project demonstrated that modelling of the resin flow can accurately identify preferred injection sites and sequences to ensure proper impregnation throughout the component. Using the optimum model prediction resulted in complete mould filling (no dry spots) and significant benefits to quality and production cost. Other members of the project team included the Air Force Research Laboratory and University of Dayton Research Institute, which helped with the modelling required to predict resin flow patterns during mould filling. Cytec Fiberite supplied the bismaleimide (BMI) resin and carbon fabric the component is made from and A&P Technology provided the complex, computer-controlled custom braiding over machined mandrels. North Coast Tool and Mold provided the
10 tonne steel and aluminium mould and the injection fixture. restraint Radius Engineering supplied the computer-controlled resin injection system. The RTM vertical tail project began at the end of 1998, one of many projects conducted under Lockheed Martin Aeronautics’ Advanced Affordability Initiative (AAI). AA1 was initiated in 1997 to demonstrate advanced material, designs and manufacturing technologies that will significantly reduce cost of aircraft components for the next generation of combat aircraft. “This RTM demonstration is a major step forward in advancing the producibility of
complex, composite aircraft components,” according to Kenneth Taylor, director of the AAI. “We are beginning to capitalize on the performance advantages of composite materials at costs that rival traditional metallic designs. These advances in composites are providing us confidence in our ability to affordably produce the next generation of fighters.” Lockheed Martin Aeronautics Co specialises in the development, production and support of military aircraft and related technologies. Its products include the F-22, F-16, X33 and Joint Strike Fighter. Mike Nipper, Lockheed Martin; tei: +I-81 7-777-4973; email: [email protected].
February 2001
RElfWDRCEDplastics
15