Startup Metro Aerospace has delivered the first shipsets of drag-reducing microvanes for the Lockheed Martin C-130 Hercules to the Royal Canadian Air Force, which should complete installation of the aerodynamic devices on its C-130J fleet in June.
Adhesively bonded onto the upswept aft fuselage on either side of the cargo ramp, the 20 small, 3D printed composite strakes slow the vortex that forms as airflow swirls around the aft of the aircraft and reduce drag, resulting in a cruise fuel-consumption saving of around 3.3%.
The upswept aft fuselage of the Hercules accounts for as much as 11% of total drag in cruise. The microvortices created by the vanes reshape the airflow around the cargo ramp, and flight tests confirmed an average 15-point reduction in drag.
Microvanes were developed by Lockheed and flight-tested on the C-130 in 2011-14 but then “sat on the shelf,” says Leslie Peters, president and CEO of Metro Aerospace. The startup was founded in 2016 by Catalyze Dallas, a venture development company specializing in commercializing innovations developed within large aerospace and defense OEMs.
Metro has licensed the microvane technology from Lockheed, which continues to provide engineering assistance, and is now pursuing FAA certification of the devices for use on the LM-100 commercial freighter version of the Hercules.
The company also plans to talk to Airbus, Peters says, about developing microvanes for the A400M and C295 transports, which have similar drag-inducing upswept aft fuselages. The U.S. Air Force flew the microvanes on a Boeing C-17 in 2016, she says, but test data is not available yet.
Each of the 18 shipsets sold to Canada cost around $90,000, and the return on investment from fuel savings can be achieved in less than a year, depending on how much the aircraft is flown, says Peters. At 1,000 flight hours per year, the annual fuel saving is $150,000; at 800 hr., it is $120,000.
“It can pay back in under a year, which is unheard of for an enhancement to the Hercules,” she says, noting that, even if annual utilization is just 400-500 hr., the payback time is 14 months.
By lowering the thrust required, the drag-reducing microvanes also reduce wear on the inboard engines, and Peters says Metro is in talks with Rolls-Royce to package the aerodynamic devices with its Series 3.5 upgrade for the C-130’s T56 engine, which itself reduces fuel burn by up to 9.7%.
A shipset includes 20 microvanes, each about 10 in. long and each different. The devices are 3D-printed in 3D Systems’ DuraFormGF, a glass-filled nylon, using selective laser sintering. Additive manufacturing means Metro can deliver in under a month without having to stock parts, Peters says.
Hercules operators can install the microvanes themselves, as Canada has. Each shipset includes a template to correctly locate the devices. Each of the microvanes will only fit in one location because of irregularities in the airframe surface, so installation is fool-proof, she says.
Metro is anticipating a second contract, from Australia for its C-130Js, and has begun working with a commercial operator. The intent is to flight-test the microvanes on their aircraft this summer, with the goal of achieving FAA supplemental type certification by year-end.
Lockheed, meanwhile, has added the microvanes to its catalog so they can be selected by customers, and a service bulletin is ready, says Peters, enabling operators to retrofit their aircraft.