Aviation Partners' blended winglets cut fuel burn up to 7% on existing jets

Fuel is one of an operator's biggest costs, but replacing a jet to save fuel is unaffordable for most owners. In 1976 NASA's Richard Whitcomb showed in wind-tunnel tests that small, nearly vertical wing-tip surfaces substantially reduce drag at cruise by recovering energy lost to wingtip vortices.

Aviation Partners, founded in 1991, turned the idea into business: Louis Gratzer's blended winglet design was certified on the Gulfstream II in 1993, the Boeing Business Jet in 2000, and later Falcon and Hawker models through the 1999 Aviation Partners Boeing joint venture. The kit bolts onto existing wings, so no new aircraft is required.

The company reports up to 7 percent less fuel burn and says its winglets have saved billions of gallons of jet fuel, and blended winglets became the most-requested upgrade in business aviation — a visible sign of a well-kept aircraft.

Sell the fuel saving as a bolt-on for planes already owned

Retrofit economics: the saving accrues on every flight of a plane the buyer already owns.

Certification on existing models removed the buyer's technical risk.

The blended curve avoided the drag penalty of sharp-angled winglets.

The Boeing joint venture opened the airliner installed base.

When the expensive fix is out of reach, find the cheap bolt-on that captures most of the benefit: a retrofit sells to the entire installed base instead of competing for new purchases.

Blended winglets became standard equipment on many business jets and common on airliners; the 737 MAX's split-scimitar tips and the Falcon 2000LX's standard winglets show how completely the retrofit idea became a factory option.