Wing deployment method and apparatus Patent
Method for deployment of flexible wing glider from space vehicle with minimum impact and loading
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Method for deployment of flexible wing glider from space vehicle with minimum impact and loading
Reentry glider approximate optimal atmospheric entry trajectories for maximizing function of terminal velocity, altitude, flight path and heading angle under terminal nonlinear constraints
For a reentry glider, approximate solutions are found in closed form for the problem of maximizing a function of the terminal velocity, altitude, flight-path angle and heading angle subject to, at most, three terminal nonlinear constraints. The results given here extend the previous results in two important ways: (1) the second-order approximation of the entry dynamics of Loh is used instead of the first-order approximation of Allen and Eggers. This approximation is found to compare extremely well with an exact numerical optimal path. (2) A three-dimensional optimization problem is solved which includes Loh's second-order approximation where the roll angle as well as the lift coefficient are determined subject to constraints which include the terminal heading angle. Furthermore, closed-form solutions can also be obtained subject to in-flight constraints on the lift coefficient and roll angle.
The possible uses of flexible wings for transportation of passengers and cargo from point to point on earth are discussed along with emergency applications of flexible wings in connection with conventional aircraft. Topics considered include gliding and soaring as a sport, towing of flexible-wing gliders for cargo delivery, powered flight with small aircraft having folding flexible wings, aerial dropping of personnel and cargo on flexible wings instead of parachutes, landing and recovery of rocket payloads by means of flexible wings, and use of flexible wings with ejection seats and as an emergency landing system for conventional aircraft.
The feasibility of utilizing instrumentation mounted on a sailplane wing is investigated to determine vortex wakes from a large aircraft. The instrumentation consisted of static and total pressure tubes and a rotating vane vorticity meter mounted in a pod on the glider wing tip. It was concluded that the study was not feasible.
A turbulent boundary layer on the fuselage of a glider was used to excite a Helmholtz resonator. The resonator orifice was flush with the surface and smaller than the boundary layer thickness. Resonator frequencies were chosen so they would tune with different portions of the boundary layer wall pressure spectrum. The resonators were excited at both the Helmholtz frequency and a standing wave frequency. The results show a shift in the Helmholtz frequency when the boundary layer is present. This shift indicates the degree to which the turbulence interacts with the acoustic motion in the orifice and modifies the end correction. Four of the nine resonators tested were 'strongly' excited and radiated considerable acoustic sound. This phenomenon occurs when turbulent eddies about the size of the orifice are convected past the orifice with the proper velocity to impose a frequency that matches a resonant frequency of the resonator. Turbulent eddies which are either smaller or larger than the orifice will not produce strong excitation.
A turbulent boundary layer on the fuselage of a glider is used to excite a Helmholtz resonator whose openings are comparable in size to the turbulent eddies in the boundary layer. The resonator was excited at both the Helmholtz frequency and a standing wave frequency. The level of the resonator response and the response frequency are the major results. A shift in the response frequency, compared to acoustic excitation, indicates an interaction of turbulent and acoustic motions and a modification of the orifice end correction. A strong excitation phenomenon occurs when the resonator and boundary layer are tuned, in which case turbulent eddies of about the orifice diameter in size flow past the orifice and impose a frequency equal to one of the resonant frequencies of the resonator.
A manned recoverable flying machine that operates both in air and space was discussed. This space shuttle precursor was proposed in the early 1900's by Eugen Sanger. The vehicle was especially to be used as the first stage of booster rockets or to ferry, supply and furnish rescue equipment for manned space stations. Basic concepts of the space aircraft, a cross between a powered booster rocket and an aerodynamic glider, are presented.
The first recorded balloon ascension in America took place on June 19, 1784, when an unmanned balloon was raised in a public demonstration at Bladensburg, Maryland. On June 24, 1784, a thirteen-year-old boy ascended in the same balloon. The history of actual flight during the nineteenth century was entirely concerned with balloons except for several gliders and models leading to the coming of the airship and the aircraft. The history of practical flight in America begins in the twentieth century. The described developments related to aerostatics are concerned with balloons, rigid airships, and blimps. In a review of the evolution of aeronautics, attention is given to general aviation and its search for a market, trends in military aeronautics, and commercial aviation. It is pointed out that American air transport had its birth on New Year's Day, 1914, at Tampa Bay, Florida. The evolution of astronautics during the period from 1957 to 1976 is also examined, taking into account scientific satellites, the Apollo project, the exploration of the planets with the aid of unmanned spacecraft, strategic reconnaissance satellites, missile alarm satellites, instrumental satellites for detecting nuclear and thermonuclear explosions, weather satellites, communications satellites, and earth resource survey and geodetic satellites.
A computer program was developed to calculate numerically the speed and circling polars of an aircraft when the lift and drag characteristics of the wing airfoils are known. The planform of the wing is described by variables which are optimized so that the cross-country speed of the glider is maximum for the particular type of thermal model. Two thermal models are compared and shown that with a greater wing area than now normally used the performance can be increased.
An experimental program was conducted with the pendular platform of the Oto-Rhino-Laryngology Clinic, which was developed for the investigation of disturbances of the equilibrium. The equilibrium sense of the glider pilot was emphasized. Results are presented.
Variables taken into account in glider flight strategy decisions are modeled. These include height of clouds, distance between thermals, time of day, water ballast, present altitude, weather changes, lift organization, and distance to goal, as well as the strength of the next thermal. Results of the Monte Carlo atmospheric model are discussed.
Research was based on a series of mechanical, electrical, and cinematographic instruments developed to measure various features of air current behavior as well as bird and airplane flight. Investigation of rising obstruction and thermal currents led to a theory of bird flight, especially of the gliding and soaring types. It was shown how a knowledge of bird flight can be applied to glider and ultimately motorized aircraft construction. The instruments and methods used in studying stress in airplanes and in comparing the lift to drag ratios of airplanes and birds are described.
Aerodynamic characteristics of wing model gliders and bird wings in particular are discussed. Wind tunnel measurements and aerodynamics of small Reynolds numbers are enumerated. Airfoil behavior in the critical transition from laminar to turbulent boundary layer, which is more important to bird wing models than to large airplanes, was observed. Experimental results are provided, and an artificial bird wing is described.
The NASA early experimental program for parawing and lifting body spacecraft recovery concepts is discussed. Simple hand drawings, in-house construction, and crude drop tests were used in lieu of a thorough stress analysis. The parawing (parasev) was controlled by manually shifting the center of gravity with respect to the center of pressure; the craft would take off while being towed at 40 KIAS. The M-2 lifting body was originally constructed with a 3/32 in. mahogany skin by a glider manufacturer and employed general aviation aircraft nose and main wheel assemblies. A minimum altitude of 200 ft was found acceptable for release of the parasev, allowing the pilot time to adjust for transients incurred at the tow release. A small landing assist rocket was furnished for the M-2/F-2 and X-24A lifting bodies to enhance stability, and landings at a maximum lift/drag ratio of 2.8 were successfully completed. The data gained were eventually applied in the development of the Shuttle.
System specifications, launch procedures, costs, payloads, and evolutionary developments in the STS are outlined. The Shuttle employs solid propellant boosters and an external cryogenic fuel tank to achieve LEO for the manned Orbiter, which can maneuver in space and return to earth like a glider. The Shuttle can place a maximum payload of 30 tons into a 275 km orbit. An Inertial Upper Stage and a Spinning Solid Upper Stage will be carried by the Orbiter in its bay and used to boost satellites into GEO. Additionally, the Orbiter is equipped with a remote manipulator system for removing cargo from the bay and for grappling satellites for retrieval or repair. The Shuttle is presently launched from Kennedy Space Center, while a second launch site is being prepared at Vandenberg AFB. The STS is intended to perform 28-40 flights per year by the end of the 1980s. An Orbital Transfer Vehicle is under study to increase the size and length of payloads which can be placed in GEO using the Shuttle. Utilization of the concept is noted to be connected with the development of a permanently manned space station.
Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.
Over the past several years the NASA Ames-Dryden Flight Research Facility at Edwards Air Force Base has developed a variety of flight flutter and ground test techniques which have been applied to an assortment of new or modified aerospace research vehicles. This paper presents a summary of these techniques and the experiences gained from these applications. Topics discussed include the roles of ground vibration testing, flight flutter testing, wind tunnel flutter model testing, predictive analyses, and aeroservoelastic considerations. Data are presented for a wide variety of aircraft, including remotely piloted vehicles, modern fighters with relaxed static stability and highly augmented flight control systems, aircraft modified for laminar flow control experiments, a glider modified for deep stall tests, and aircraft with skewed or forward swept wings. The conclusions include a brief discussion of future directions in flight flutter testing at Ames-Dryden.