Small Winglets Could Save the U.S. Air Force Big on Fuel

WIB air June 10, 2016 0

But the flying branch isn’t entirely convinced by JOSEPH TREVITHICK As the U.S. Air Force faces the prospect of a severe and potentially unavoidable...

But the flying branch isn’t entirely convinced

by JOSEPH TREVITHICK

As the U.S. Air Force faces the prospect of a severe and potentially unavoidable budget crisis, the service has every incentive to save money by squeezing extra life out of older airplanes. New winglets for venerable C-130 transports are one option, but the Air Force isn’t entirely convinced just yet.

In April, test pilots took a specialized MC-130J Commando II on eight flights around Eglin Air Force Base in Florida. Defense contractor Lockheed Martin had added two relatively small — but significant — upturned sections to the tips of the wings.

“The Air Force has encouraged contractors to develop and bring forward ideas to save fuel,” Maj. Matthew Quinton, the deputy chief at the Air Force Research Laboratory’s Acquisition Systems Support Branch, told War Is Boring in an email.

“If the engineering predictions are correct, we expect to see an average of three percent fuel savings across the normal flight regime.”

Three percent might seem like a paltry amount, but for the sprawling Air Force, every gallon saved adds up big. The flying branch inevitably spends billions of dollars per year to gas up its aircraft, give or take some variation due to fluctuating global prices.

H-model C-130 Hercules transport planes can hold up to 60,000 pounds of fuel. During the 2015 fiscal year, the Air Force’s entire fleet of the standard four-engine planes flew more than 180,000 hours.

Four years ago, the service spent around $10 billion on fuel, according to a report by Air Force Magazine. Arguably, the key to U.S. military hegemony is logistics — and in logistics, cost rules everything. If the Air Force could cut fuel consumption by three percent across the board, that could free up some $300 million in extra cash.

So, while the flying branch began testing a new five-foot winglet on a special purpose MC-130, Lockheed has proposed fitting its fuel-efficiency winglets to all C-130s.

But that’s probably a long way off.

At top and above — the modified MC-130J with the new winglets.

As of May, engineers were still poring over the data from the flight tests, Quinton said. After putting a scale model through tests in a wind tunnel, the Air Force wanted to check if the real plane — with the winglets — handled the same way.

The Air Force will still need to conduct more test flights to prove whether the winglets save enough fuel to make them worthwhile.

Lockheed has tried to sell the modifications before. The company developed the winglets with internal funding in 2009, but three years later, Air Force funding “was committed to other fuel efficiency projects,” Quinton said.

As a result, Lockheed stopped work on the design, despite showing off the patented feature on a standard C-130J transport. The next year, the flying branch dug out the proposal when it looked at upgrade options for its MC-130s as part of a project initially called New Magic.

In addition to the winglets, New Magic included proposals for engine upgrades, new propellers and other fuel saving modifications. The program also included updates that would shorten the distance a C-130 needed to take off and land, help hide it from enemy defenses and allow the plane to lug more gas and cargo.

At that time, all of the alternatives looked more promising than Lockheed’s winglets. New motors would save the Air Force three percent on the costs of flying the MC-130J. The upgrade would cut fuel costs on older MC-130Hs by more than twice that amount.

Callsign: Spectre

A set of lift-producing microvanes could trim fuel expenditure on both types by around three percent. A special control system for the moving parts in the wings could cut another one or two percent. In addition to the winglets, Lockheed was behind both of these proposed additions.

A complete package offered up by Snow Aviation potentially offered between eight and 13 extra hours of flight time, according to a briefing War Is Boring obtained via the Freedom of Information Act. A similarly all-encompassing 2008 Northrop Grumman concept, dubbed the C-130M, claimed it could cut fuel needs by nearly a third.

But according to the Air Force presentation, the engineers believed the New Magic modifications would only save less than two percent on fuel costs at the time. On top of that, they worried that the additions might damage the wing or otherwise speed up normal wear and tear.

Still, C-130s with the new wing-tips could fly farther or spend more time over the battlefield. Given these benefits, the flying branch speculated the upgrade would actually be best suited to the heavily armed AC-130 gunships. Censors redacted how much the service expected the changes would cost.

Unfortunately, in April 2013, the Air Force scrapped New Magic — by then renamed Super Sport — entirely. Less than a year later, Lockheed finally sold the design to the flying branch as part of the much smaller Air Force Research Laboratory project.

Despite the winglets’ uncertain future, the Air Force could definitely use the savings if they work. But despite more than six years of development, engineers are still trying to figure out if the new wingtips are actually … worth it.

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