639. The Weight Aspects of Energy Maneuverability

Paper

Abstract

The inclusion of energy maneuverability requirements in the preliminary design phase for fighter aircraft results in design parameter combinations to which the weapons system weight is extremely sensitive. Energy Maneuverability (EM) is defined as the relationship of energy tooperational maneuvering and efficiency. A review of EM requirement sresulted in seven performance qualities being identified as major contributors to the overall aircrafts weight. These are acceleration capability, attainable altitudes, maximum velocities, turning abilities, armament/avionic combinations, mission radii, and combat time. The design values for each of the above qualities are developed by defining the same characteristics for anticipated threats and evaluating them in four areas. These areas are load factor capability (turning ability), energy levels (maneuvering capability dependent on energy developed by speed-altitude combinations), energy management (the ability to change energylevels), and effeciency (rate of fuel consumption).
From the above, four primary weight parameters evolve which must be evaluated for not only the maneuvering parameters but also for requirements independent of maneuvering capability such as takeoff distances,l anding distances, alternate mission ranges and alternate mission strength levels. These weight parameters are wing loading (W/S), thrustloading (T/W), fuel fraction (Wf/Wow) and strength level. Weight analyses must be prepared for both independent and simultaneous variations to identify the areas to which weight is more sensitive. Concurrent weight growth factor studies allow appraisals of the weight value of such items as added electronic capability, state-of-the-art advancements, multi-service impacts, and alternate mission items.