Military Materials, Mods Could Cut Airliner Fuel Burn

Written by Charles Alcock at AINonline – September 15, 2020

A pair of Texas-based sister companies are offering a combination of solutions to reduce the fuel consumption of airliners. Between them, they say they are addressing two of the three key carbon reduction strategies proposed by ICAO to lower air transport’s environmental footprint, namely weight reduction and improved aerodynamics (the third being improved engines).

Alpine Advanced Materials says it is seeing growing demand for its HX5 thermoplastic nanocomposite technology, which is replacing aluminum for multiple cabin interior fittings. Meanwhile, its sibling, Metro Aerospace, seeks to expand applications for its Microvane drag-reducing modifications.

Lockheed Martin’s Skunk Works Advanced Development Programs unit developed HX5 at a cost of around $50 million, initially for use on the F-35 fighter. The composite material has also been used on Sikorsky’s S97 Raider helicopter, as well as on other rotorcraft and UAVs. Alpine acquired the technology in 2017 and has since spent around another $10 million to develop it for civil aircraft applications.

According to Alpine president Roger Raley, HX5 weighs around half as much as the 6061 aluminum product it replaces while retaining as much as 94 percent of its environmental properties, most notably strength. The material is approved to NASA’s TRL 9 standard for technology readiness and is increasingly being used for airline seats and other cabin structures.

Raley told AIN that using HX5 also reduces the number of components in each unit, which lessens the maintenance burden. For instance, in a seat, the number of components might be reduced from around 12 to 5, including the main frame, tray table, and armrests. Alpine says the material can also be used for galleys, lavatories, as well as to replace the large number of aluminum fasteners used in aircraft.

Alpine Advanced Materials says that its HX5 composite material provides a lightweight alternative to aluminum for aircraft structures.

Alpine uses injection molding processes to produce structures from HX5. They are flexible and also result in reduced carbon dioxide emissions in the manufacturing process. On the downside, the pressure required makes it hard to use to make larger external aircraft structures and different manufacturing techniques would need to be developed to overcome the limitation.

Raley said that his team has spoken with several leading airlines, including American Airlines, Delta Air Lines, and British Airways, as it believes air carriers could be strong advocates for increased use of HX5. At the same time, the company has been in contact with some leading component and aerostructures manufacturers, including Safran and Recaro.

Meanwhile, Metro Aerospace is harnessing another technology developed by Lockheed Martin and now being offered under license for civil applications. Microvanes reduce drag by generating swirl in the opposite direction to the vortices forming around a fuselage.

To date, they have been installed on the aft fuselage of aircraft such as the C-130 military transport/freighter, but the company is doing more engineering work to devise applications on other aircraft and on other parts of fuselages. Metro produces the “vanes” using 3D printing processes.

In 2019, Metro partnered with Lynden Air Cargo to develop a supplemental type certificate to fit Microvanes to the rear fuselage of its C-130 fleet. According to the company, the fuel reduction achieved by the modification alone amounts to between 3 and 6 percent on a C-130 or C-17 aircraft. It estimates that the savings might run up to around 2 percent on a more modern passenger airliner.

According to Tim Watkins, Metro’s vice president for business development, the fuel efficiencies delivered by Microvanes could make a difference as airlines consider how they might adjust their fleets as demand starts recovering in the wake of the Covid-19 pandemic. Along with their colleagues at Alpine, the Metro team is currently finding airline managers distracted by the immediate effects of the emergency, but they sense growing interest in any incremental measures that will deliver the combined economic and environmental advantages of reduced fuel burn.

Both companies operate under the ownership of investment group Catalyze Dallas, which focuses on finding commercial applications for defense technologies.