7,920 research outputs found
Application of Hybrid Laminar Flow Control to Global Range Military Transport Aircraft
A study was conducted to evaluate the application of hybrid laminar flow control (HLFC) to global range military transport aircraft. The global mission included the capability to transport 132,500 pounds of payload 6500 nautical miles, land and deliver the payload and without refueling return 6500 nautical miles to a friendly airbase. The preliminary design studies show significant performance benefits obtained for the HLFC aircraft as compared to counterpart turbulent flow aircraft. The study results at M=0.77 show that the largest benefits of HLFC are obtained with a high wing with engines on the wing configuration. As compared with the turbulent flow baseline aircraft, the high wing HLFC aircraft shows 17 percent reduction in fuel burned, 19.2 percent increase in lift-to-drag ratio, an insignificant increase in operating weight, and a 7.4 percent reduction in gross weight
Lockheed laminar-flow control systems development and applications
Progress is summarized from 1974 to the present in the practical application of laminar-flow control (LFC) to subsonic transport aircraft. Those efforts included preliminary design system studies of commercial and military transports and experimental investigations leading to the development of the leading-edge flight test article installed on the NASA JetStar flight test aircraft. The benefits of LFC on drag, fuel efficiency, lift-to-drag ratio, and operating costs are compared with those for turbulent flow aircraft. The current activities in the NASA Industry Laminar-Flow Enabling Technologies Development contract include summaries of activities in the Task 1 development of a slotted-surface structural concept using advanced aluminum materials and the Task 2 preliminary conceptual design study of global-range military hybrid laminar flow control (HLFC) to obtain data at high Reynolds numbers and at Mach numbers representative of long-range subsonic transport aircraft operation
Notes on the Prediction of Shock-induced Boundary-layer Separation
The present status of available information relative to the prediction of shock-induced boundary-layer separation is discussed. Experimental results showing the effects of Reynolds number and Mach number on the separation of both laminar and turbulent boundary layer are given and compared with available methods for predicting separation. The flow phenomena associated with separation caused by forward-facing steps, wedges, and incident shock waves are discussed. Applications of the flat-plate data to problems of separation on spoilers, diffusers, and scoop inlets are indicated for turbulent boundary layers
Full-scale Investigation of a Wing with the Leading Edge Swept Back 47.5 Degrees and Having Circular-arc and Finite-trailing-edge-thickness Ailerons
Exploratory Investigation at a Mach Number of 5.20 of the Longitudinal Aerodynamic Characteristics of Flat-bottom Bodies
Langley Full-scale-tunnel Investigation of the Factors Affecting the Static Lateral-stability Characteristics of a Typical Fighter-type Airplane
The factors that affect the rate of change of rolling moment with yaw of a typical fighter-type airplane were investigated in the Langley full-scale tunnel on a typical fighter-type airplane.Eight representative flight conditions were investigated in detail. The separate effects of propeller operation, of the wing-fuselage combination, and of the vertical tail to the effective dihedral of the airplane in each condition were determined. The results of the tests showed that for the airplane with the propeller removed, the wing-fuselage combination had positive dihedral effect which increased considerably with increasing angle of attack for all conditions. Flap deflection decreased the dihedral effect of the wing-fuselage combination slightly as compared with that with the flaps retracted. Flap deflection resulted in negative dihedral effect due to the vertical tail. Propeller operation decreased the lateral stability parameter of the airplane for all the conditions investigated with larger decreases being measured for the flaps deflected conditions
A Summary of Drag Results from Recent Langley Full Scale Tunnel Tests of Army and Navy Airplanes
Langley Full-scale-tunnel Investigations of the Maximum-lift and Stalling Characteristics of a Trapezoidal Wing of Aspect Ratio 4 with Circular-arc Airfoil Sections
Maximum-lift characteristics of a wing with the leading-edge sweepback decreasing from 45 degrees at the root to 20 degrees at the tip at Reynolds numbers from 2.4 x 10(exp 6) to 6.0 x 10(exp 6)
Low-speed Lateral Stability and Aileron-effectiveness Characteristics at a Reynolds Number of 3.5 x 10(exp 6) of a Wing with Leading-edge Sweepback Decreasing from 45 Degrees at the Root to 20 Degrees at the Tip
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