https://c8.alamy.com/comp/PAEJWT/maintenance-contractors-with-the-414th-flight-test-squadron-perform-engine-checks-on-a-test-mc-130j-at-eglin-air-force-base-fla-the-aircraft-was-fitted-with-vertical-fins-on-each-wing-called-winglets-the-413th-flight-test-squadron-aircrew-and-engineers-tested-the-modified-aircraft-over-eight-flights-the-goal-of-the-tests-was-to-collect-data-on-possible-fuel-efficiency-improvements-and-performance-with-the-winglets-and-lift-distribution-control-system-installed-us-air-force-photosamuel-king-jr-PAEJWT.jpg