AFRL Researchers Perform C-130 Functional Tip Tank Tests

  • Published
  • By Air Vehicles Directorate
  • AFRL/RB
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  AFRL worked in conjunction with Snow Aviation to perform tests on a modified C-130E aircraft fitted with functional tip tanks, eight-bladed NP2000 propellers, and extended dorsal and rudder surfaces. During the testing, which involved multiple flights, researchers measured tip tank impact on stall speed, minimum controllable air and ground speeds, cruise ceiling, specific range, wing bending, drag, takeoff and landing distances, and aileron effectiveness. Data collected using Snow Aviation's onboard instrumentation suite, which operated throughout the test activity, indicated that relative to a "stock" C-130E, the modified aircraft offers a 15% improvement in takeoff and landing distances, a 10% improvement in aircraft stall speed, a 5% improvement in minimum controllable speed, a 500 ft increase in ceiling, a 5% increase in specific range, and a 50% reduction in audible range.

The researchers compared their test results to data acquired during recent C-130 baseline testing, conducted Fall 2006. The purpose of the latest effort was not only to determine the effects of adding tip tanks to aircraft already modified to include improved propellers and extended aerodynamic surfaces, but also to measure the tip tanks' impact on flight characteristics. The transmission of the team's experimental
results to the user community--a group that includes Air Force Special Operations Command, Air Mobility Command, and the C-130 System Program Office--will help to raise awareness regarding these technologies.

Tip tanks are fuel tanks mounted at the end (i.e., the tip) of an aircraft's wings. As potential replacements for traditional C-130 fuel tanks, tip tanks could possibly improve aileron effectiveness and also reduce the configuration's drag--increasing both fuel efficiency and capacity. A follow-on project will include further tests conducted using improved fuel measurement and pressure-sensing devices. These precision tests will facilitate a more in-depth look at the impacts of the tip tanks, improved propellers, and extended aerodynamic surfaces. The tip tank effort--just one of Snow Aviation's several C-130 modifications designed to improve the aircraft's short takeoff and landing performance and controllability--has significant potential for improving the aircraft's fuel efficiency.