On the horizon for C-130 fuel efficiency improvements:
Winglets - Five foot tall blended winglets. These would only be applicable to the J-model as the wing box has been strengthened to allow for the higher loads. They are looking at a savings of 140 pounds/hour.
Already in testing are the micro vanes/vortex generators that look to lower the drag of the aft fuselage, yielding fuel savings of 167 pounds/hour.
Lift distribution control system. It deflects the ailerons to reduce the lift on the outer wings. The aircraft is also trimmed in a nose-up attitude during cruise to improve lift. It will hopefully yield an additional range of 1,400 miles in a heavy-weight configuration or a 10 increase in maximum payload or 67 pound/hour lower fuel flow at long-range cruise.
And let's get one thing straight. There's a big difference between a pilot and an aviator. One is a technician; the other is an artist in love with flight. — E. B. Jeppesen