Arrow wings for supersonic cruise aircraft

Abstract

The arrow wing planform has a far greater range potential than the delta wing planform for utilization on a commercial supersonic cruise vehicle. A supersonic cruise vehicle concept must be configured to favor cruise efficiency. The arrow wing planform cruise lift-drag ratio is approximately one unit higher than the delta wing. The small weight advantage of the delta wing cannot offset the large cruise efficiency advantage of the arrow wing. The low-speed aerodynamic characteristics of the arrow wing are acceptable and can be further improved by continued research and development. For this, additional analytical tools need to be developed and wind tunnel tests conducted to provide verifications and empirical adjustments to the analytical tools. The major emphasis for arrow wing development should be in the low-speed regime. The design challenge is to seek out design features and refinements that remove any deficiencies of the arrow wing, while not sacrificing the superior cruise efficiency. ING planform selection is a classic problem for commercial supersonic cruise vehicles (SCV's). This fact is highlighted by the various proposed and actual supersonic aircraft that were studied during the USA FAA/SST program, the British/French Concorde program, and the Russian TU 144 program of the 1960's. The NASA SCAT series included arrow, delta, and variable-sweep concepts. Lockheed, Boeing, Douglas, and North American addressed many of the same concepts and modifications thereof, as well as their own concepts. The final Lockheed and Boeing configurations were fixed-wing delta concepts. Both the Concorde and the TU 144 configurations are fixed-wing delta (ogive) concepts. The basic conclusion to be drawn from these SST planform selections is that, based on the available technology, design philosophy, and design requirements of the 1960's, a fixed delta-type wing planform was the unanimous choice. Numerous considerations enter into the selection of planform parameters that lead to the final choice of wing planform. These include such items as cruise lift-drag ratio (LID}, weight, low-speed aerodynamic characteristics, and simplicity. Based on the mission requirements of a given supersonic aircraft, trade studies of the various considerations just mentioned establish the optimum wing planform. These trade studies must be reiterated every time technology is advanced, design philosophy reevaluated, and/or design requirements updated. The first-generation SST developed by Lockheed during the FAA/SST program of the 1960's featured a double-delta planform, tailless concept. The delta wing planform was Lockheed's first choice due to its lighter weight, superior low- speed aerodynamic characteristics, and simplicity. The arrow wing planform was Lockheed's second choice. This planform displayed superior cruise efficiency (cruise lift-to-drag ratio), but was heavier than the delta planform. Also, there was concern with regard to the low-speed aerodynamic charac- teristics of this planform. The variable-sweep wing concept