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ASALM (Advanced Strategic Air-Launched Missile) is a supersonic air vehicle designed to be air-launched from a carrier aircraft. The four aft aerodynamic control vanes are folded to maximize the number of missiles carried on-board. The unfolding (erection) system must be small, energetic, fast, and strong. The materials selected and problems that arose during development of the unfolding system are described.
Wind-tunnel tests were conducted to evaluate the effects on performance of modifying a 13-percent-thick low-speed airfoil. The airfoil contour was altered to reduce the aft upper surface pressure gradient and hence delay boundary layer separation at typical lift coefficients for light general aviation airplanes. The tests were conducted at a Mach number of 0.15 or less over a Reynolds number range from about 1,000,000 to 9,000,000.
Predictions made with NASA's aircraft noise prediction program (ANOPP) were compared with flyover noise data. A data base of six flyover noise runs for the DC-10-40/JT9D-59A configuration was used. For all power settings, ANOPP consistently underpredicted the low frequency spectral levels, overpredicted high frequency spectral levels and, consequently, overpredicted the inlet and aft PNLT time histories.
Wind tunnel tests were conducted to examine various aspects of the drooped-leading edge airfoil which reduces the tendency for an airplane to enter a spin after stall occurs. Three baseline models were used for tests of two dimensional models: NACA 0015, 0014.6, and 0014.2. The 14.6% and 14.2% models were derived from NACA 0015 sections by increasing the chord and matching the profiles aft section. Force, balance data (lift, drag, pitching moment) were obtained for each model at a free-steam Reynold's number of 2.66 x 10 to the 6th power/m. In addition, oil flow visualization tests were performed at various angles of attack. An existing NACA 64 sub 1 A211 airfoil was used in a second series of tests. The leading edge flap was segmented in three parts which allowed various baseline/drooped leading edge configurations to be tested. Force balance and flow visualization tests were completer at chord Renolds numbers of 0.44 x 10 to the 6th power, 1.4 x 10 to the 6th power, and 2.11 x 10 to the 6th power. Test results are included.
Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after five years' service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 150 C (300 F) service aft engine fairing. The fairings have accumulated a total of 40,534 hours, with one ship set having 16,091 hours service as of Feb. 11, 1979. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings.
The characteristics were determined of a lift cruise fan V/STOL multi-mission configuration in the near proximity to the edge of a small flat surface representation of a ship deck. Tests were conducted at both static and forward speed test conditions. The model (0.12 scale) tested was a four fan configuration with modifications to represent a three fan configuration. Analysis of data showed that the deck edge effects were in general less critical in terms of differences from free air than a full deck (in ground effect) configuration. The one exception to this was when the aft edge of the deck was located under the center of gravity. This condition, representative of an approach from the rear, showed a significant lift loss. Induced moments were generally small compared to the single axis control power requirements, but will likely add to the pilot work load.
The aerodynamic characteristics of the augmentor wing concept with hypermixing primary nozzles were investigated. A large-scale semispan model in the Ames 40- by 80-Foot Wind Tunnel and Static Test Facility was used. The trailing edge, augmentor flap system occupied 65% of the span and consisted of two fixed pivot flaps. The nozzle system consisted of hypermixing, lobe primary nozzles, and BLC slot nozzles at the forward inlet, both sides and ends of the throat, and at the aft flap. The entire wing leading edge was fitted with a 10% chord slat and a blowing slot. Outboard of the flap was a blown aileron. The model was tested statically and at forward speed. Primary parameters and their ranges included angle of attack from -12 to 32 degrees, flap angles of 20, 30, 45, 60 and 70 degrees, and deflection and diffuser area ratios from 1.16 to 2.22. Thrust coefficients ranged from 0 to 2.73, while nozzle pressure ratios varied from 1.0 to 2.34. Reynolds number per foot varied from 0 to 1.4 million. Analysis of the data indicated a maximum static, gross augmentation of 1.53 at a flap angle of 45 degrees. Analysis also indicated that the configuration was an efficient powered lift device and that the net thrust was comparable with augmentor wings of similar static performance. Performance at forward speed was best at a diffuser area ratio of 1.37.
Tabulated surface pressure data for a series of four forebodies which have analytically defined cross sections and which are based on a parabolic arc profile having a 20 deg half angle at the nose are presented without analysis. The first forebody has a circular cross section, and the second has a cross section which is an ellipse with an axis ratio of 2/1. The third has a cross section defined by a lobed analytic curve. The fourth forebody has cross sections which develop smoothly from circular at the pointed nose through the lobed analytic curve and back to circular at the aft end. The data generally cover angles of attack from -5 deg to 20 deg at angles of sideslip from 0 deg to 5 deg for Mach numbers of 1.70, 2.50, 3.95, and 4.50 at a constant Reynolds number.
An analysis of pressure and strain-gage data from space shuttle wind tunnel test IA119 and IA138 was performed to define the influence on aerodynamic characteristics resulting from the main propulsion system and solid rocket booster plumes. Aerodynamic characteristics of each of the elements, the components and total vehicle of the space shuttle vehicle during ascent flight was considered. Pressure data were obtained over the aft portions of the space shuttle wind tunnel model in addition to wing and elevon gage data.
The CASTS Project initiated to develop graphite fiber/polyimide matrix (GR/PI) composite structures with 589K operational capability for aerospace vehicles is described. Near term tasks include screening composites and adhesives for 589K service, developing fabrication procedures and specifications, developing design allowables test methods and data, design and test of structural elements, and construction of a full scale aft body flap for the space shuttle orbiter vehicle for ground testing. Far term tasks include research efforts directed at new materials, manufacturing procedures and design/analysis methodology. Specific results discussed include: (1) identification of four GR/PI composites and three PI adhesives with 589K service potential for periods ranging from 125 to 500 hours; (2) development of an adhesive formulation suitable for bonding reusable surface insulation (RSI) titles to 589K (GR/PI) substructure; (3) the capability to fabricate and nondestructively inspect laminates, hat section shaped stiffeners, honeycomb sandwich panels, and chopped fiber moldings; and (4) test methods for measuring design allowables at 117K.
The aircraft noise prediction program (ANOPP) was used to predict the far-field noise characteristics of an L-1011 aircraft equipped with RB.211-524B engines. Actual flight noise was compared with noise predicted for the same operating and weather conditions. Correlation of predicted and measured results was very good in the aft quadrant of radiated noise. Predicted noise levels were significantly different from measured values in the forward quadrant because fan noise was predicted high. Since the major noise sources were fan and core, corrections are supplied to adjust ANOPP fan and core noise components so that the total predicted noise matches the measured L-1011 noise levels.
A Shuttle-borne tether system capable of deploying a tether to radial distances as great as 100 km was described by Rupp and Laue (1978). The system as discussed by Rupp and Laue would have a total mass of 700 kg and would be mounted on one Shuttle pallet. It would consist of a tether reel mechanism complete with a servo drive motor and control sensors, a boom with docking probe used for initial deployment and subsequent retrieval, some type of satellite weighing 175 kg, up to 100 km of synthetic or metallic tether approximately 1 mm in diameter, a digital control computer, and a control and display panel on the Orbiter aft flight deck for crew operation. The primary use of a tether system for geological applications would be in the measurement of those magnetic and gravitational fields associated with geological structures. The major appeal in connection with atmospheric applications is the system's ability to extend instrumentation down into the lower thermosphere and possibly the mesosphere.
Effects of elevon-induced three-dimensional shock-wave turbulent boundary-layer interactions on hypersonic aircraft surfaces are analyzed. Detailed surface pressure and heating rate distributions obtained on wing-elevon-fuselage models representative of aft portions of hypersonic aircraft are compared with analytical and experimental results from other sources. Examples are presented that may be used to evaluate the adequacy of current theoretical methods for estimating the effects of three-dimensional shock-wave turbulent boundary-layer interactions on hypersonic aircraft surfaces.
Classical unsteady thin airfoil theory fails for low frequencies at the subsonic freestream Mach number, because of the formation of a shock wave that shields the forward region of the airfoil from aft generated disturbances. In the present paper, the classical thin airfoil theory is modified to account for the presence and induced motion of such shocks. The modification consists of taking the steady local Mach number to be a simple step discontinuity, normal to the undisturbed flow, separating two uniform regions. Predicted regions are shown to correlate well both with the experiment and finite difference calculations.
A survey of research relative to scale effects on supercritical airfoils has been conducted. The results of this survey indicated that Reynolds number scale effects have a significant impact on airfoil design and performance. Further, this impact is greater for supercritical airfoils than for conventional airfoils. It was found that low Reynolds number drag data could be extrapolated to high Reynolds number conditions provided the flow was attached and the pressure distribution shape did not change appreciably. Airfoil lift and pitching-moment data obtained at low Reynolds numbers cannot be extrapolated to full-scale values. Viscous theoretical transonic analysis methods currently under development will significantly improve the ability of the designer to account for scale effects. Boundary-layer manipulation in low Reynolds number facilities using natural transition or aft located transition strips to simulate high Reynolds number conditions was shown to be an uncertain test procedure and reliance should be made on high Reynolds number facilities if available.
The detached experiment carrier (DEC) system aids the adaptation of small, low-weight experiments to Space Shuttle missions. The carrier system consists of the detached experiment carrier (free-flyer), a command station at the Orbiter aft station, and a flight support station in the Orbiter payload bay. The carrier is a compact vehicle that is radio controlled by the Shuttle crew. It uses control television, command, and cold gas propulsion systems to deploy experiments from and later rendezvous with the Orbiter. The carrier propulsion system also maintains the attitude control required during experiment execution. Results of engineering investigation, analysis, component design and development, and testing indicate that the DEC system concept is practical. Results of preliminary engineering investigations, including maneuvering system handling qualities and television/telemetry display formats, indicate that the concept of flying the DEC 'out of' and 'into' the Orbiter payload bay is both safe and practical for small, compact free-flyer deployment and retrieval. This paper describes the carrier system, its operations, and potential applications.
Flight experience on the Nike Black Brant V has demonstrated the existence of plume induced flow separation over the fins and aft body of the Black Brant V motor. Modelling of the forces associated with this phenomenon as well as analysis of the resultant vehicle coning motion and its effect on the velocity vector heading are presented. A summary of Nike Black Brant V flight experience with high altitude dynamic instability is included.
A theoretical study has been made of the effects of flight on noise from dual-flow coaxial jets. The theory is based on an instability free, vortex sheet flow model. It is shown that the flight effects are more favorable (and hence produce less forward-arc amplification) for coaxial jets than for single-stream jets. Further, the theory predicts that, like the single-stream jet case, flight effects induce noise amplification in the forward quadrant and attenuation in the aft quadrant and have virtually no effect at theta = 90 deg to the jet axis, where theta is the angle between the directions of convection and emission at the retarded time. Amplification in the forward quadrant diminishes as the inner flow velocity increases and becomes optimum when the outer-to-inner velocity ratio is about 0.5. The theory also shows that the higher the outer-to-inner area ratio, the lower the forward-arc amplification due to flight.