Abstract: In the context of sound transmission through aircraft fuselage panels, equations for the field-incidence transmission loss (TL) of a single-walled panel are derived that include the effects of external air flow, panel curvature, and internal fuselage pressurization. Flow is shown to provide a modest increase in TL that is uniform with frequency up to the critical frequency. The increase is about 2 dB at Mach number M = 0.5, and about 3.5 dB at M = 1. Above the critical frequency where TL is damping controlled, the increase can be slightly larger at certain frequencies. Curvature is found to stiffen the panel, thereby increasing the TL at low frequencies, but also to introduce a dip at the 'ring frequency' of a full cylinder having the same radius as the panel. Pressurization appears to produce a slight decrease in TL throughout the frequency range, and also slightly shifts the dips at the critical frequency and at the ring frequency.

Abstract: A staggered channel aircraft having a forward pair of wings and a rearward pair of wings. The forward pair of wings are substantially horizontal and are swept backward from the fuselage to join at their tips the pair of rearward wings. The rearward wings are sloping and are swept backward from their tips to join the fuselage in a substantially triangular-like configuration.

Abstract: A tandem wing aircraft is provided having two independent spaced apart fuselages and two wings of similar area, a lower forward wing and a higher aft wing. The lower forward wing is attached to the forward region of each of the spaced apart fuselages; the higher aft wing is aerodynamically spaced apart from and located above the aft region of the spaced apart fuselages. An aft strut member is disposed between the aft wing and each of the fuselages; each aft strut member has a length sufficient to cause the wing tips of the lower forward wing and the upper aft wing to be vertically spaced apart by a distance of at least 25% of the span of either of the wings.

Abstract: A vertical take-off and landing aircraft features an improved tail-lifting rotor and rotor directional controls. A new type of suction pressure jet-mechanical-flap rotor blade with a higher coefficient of lift is employed. The aircraft has a mechanism for loading and unloading passengers and a more efficient method of handling baggage and cargo. A much more efficient utilization of space in the fuselage is achieved through a reduced height passenger space and overhead rotor storage compartment.

Abstract: A rotor arrangement for an aircraft comprising two coaxially counter-rotatable rotators, each rotor being journaled freely rotatable about an imaginary axis of rotation common to both rotors on or through a fuselage part or a support member, each fuselage part or support member being either rigidly connected to or journaled on the fuselage, each rotor together with the other respective rotor or with the component part of the support member or fuselage part supporting the first mentioned rotor constituting an integral part of an electromotor by forming the counteracting parts of the electromotor ("rotor" and "stator") which rotate relative to one another by securing a plurality of poles of the electromotor to the respective rotor and by arranging on the other counter-rotating rotor or on the component part of the support member or fuselage part supporting the first mentioned rotor the corresponding poles of the electromotor facing toward the poles of the respective rotor such that a reciprocal field effect exists, at least the poles provided on one rotor or on the respective component part of the support member or fuselage part being electrically connected to a current generator which produces a frequency current.

Abstract: Device for diminishing tip vortices in an aircraft. For the purpose of diminishing the tip vortices generated by aircraft there are provided retractable foils at or near the airfoil, as wing, tips in question and projecting upwardly and/or downwardly therefrom. The operation of the retractable foils is satisfactory if such foils are parallel to the centerline of the aircraft but it is preferable if such foils are angled slightly with respect thereto, such as if the leading edge of the upper foil is angled approximately 10° inwardly toward the fuselage of the aircraft and the bottom foil is oppositely angled also approximately 10°. The retractable foils, in addition to diminishing wing tip vortices, also when used on wing tips improve the rate of climb of an aircraft at a given engine setting and appear to diminish the area over which the major amounts of noise generated by the aircraft will be dispersed. The foils may be fully retractable into the aircraft wing, but if not fully retracted, they will each provide a small streamlined ridge projecting upwardly and/or downwardly adjacent the tip of the aircraft wings which will improve the lift characteristics of the wings by diminishing air flow around the end of the wings sufficiently to move than compensate for the drag otherwise created. The foils are also advantageously applicable to other aircraft components, such as flaps, stabilizers or elevators.

Abstract: The disclosed method and apparatus enables movement of containerized and palletized cargo into a cargo aircraft through a door in the side of the fuselage which has a smaller width than the length of the cargo. The disclosed preferred embodiment includes an array of floor mounted steerable drive wheel units and an attenuated, shock absorbing pivot-stop.

Abstract: An electrically powered scale model airplane is disclosed in which a rechargeable electric storage battery is positioned within the aircraft fuselage to balance the weight of a nose mounted direct drive motor. A switch for energizing the motor driving the propeller is arranged to be adjusted from an "off" position to an "on" position by remotely operated control cables acting through a bellcrank assembly used to change the orientation of the aircraft elevator during flight, thus allowing the aircraft to be operated by a single individual. The switch may be manually operated to an "off" position from the outside of the aircraft fuselage in preparation for recharging of the battery. In addition, the entire connecting means between the storage batteries, the recharging battery switch assembly, and the propeller motor are made by only three rigid wires within the aircraft fuselage, two of these wires providing switch contacts for energizing the motor, thus greatly reducing the overall cost of assembling this device.

Abstract: An aerodynamic spoiler mounted on the upper forward surface of the fuselage of an aircraft which is equipped to be refueled by another aircraft while in flight. The spoiler counteracts aerodynamic disturbances produced by the refueling boom and the resultant instabilities in pitch in the aircraft receiving fuel. Four species of the spoiler are disclosed and the device may be made retractable to eliminate drag when not in use.

Abstract: A supersonic airplane having a wing mounted for pivotal movement between a conventional position orthogonal to the fuselage and an oblique position relative to the fuselage has its vertical pivot axis offset from the mean aerodynamic center of lift of the wing when the wing is in the conventional position. The pivot axis can, for example, be offset rearwardly from the mean aerodynamic center of lift and transversely relative to the fuselage in the direction of the trailing tip of the wing when in an oblique position to counteract pitch and roll moments induced by the aeroelastic effect on the wing and by the center of pressure shift occurring at supersonic flight speeds.

Abstract: A helicopter rotor and transmission mounting and vibration isolation system in which the transmission is supported from the fuselage by a plurality of elastomeric mounts which are selectively positioned and focused to establish a system roll axis and a system pitch axis on opposite sides of the elastomeric mounts and which mount members are of selected stiffness to establish selected roll stiffness and selected pitch stiffness of the system, to establish the natural frequencies of the system sufficiently below the blade passage frequency to minimize the response of the fuselage to forces and moments imparted by the helicopter rotor and to provide selected torque restraint and lift restraint for the system.

Abstract: The effects of active controls on flutter suppression and gust alleviation of the Arava twin turboprop STOL transport and the Westwind twinjet business transport are investigated. The active control surfaces are introduced in pairs which include, in any chosen wing strip, a 20-percent chord leading-edge control and a 20-percent chord trailing-edge control. Each control surface is driven by a combined linear-rotational sensor system located on the activated strip. The control law is based on the concept of aerodynamic energy and utilizes previously optimized control law parameters based on two-dimensional aerodynamic theory. The best locations of the activated system along the span of the wing are determined for bending-moment alleviation, reduction in fuselage accelerations, and flutter suppression. The effectiveness of the activated system over a wide range of maximum control deflections is also determined. Two control laws are investigated. The first control law utilizes both rigid-body and elastic contributions of the motion. The second control law employs primarily the elastic contribution of the wing and leads to large increases in the activated control effectiveness as compared with the basic control law. The results indicate that flutter speed can be significantly increased (over 70 percent increase) and that the bending moment due to gust loading can be almost totally eliminated by a control system of about 10 to 20 percent span with reasonable control-surface rotations.

Abstract: Two formulations of the oblique wing flutter problem are presented; one formulation allows only simple wing bending deformations and rigid body roll as degrees of freedom, while the second formulation includes a more complex bending-torsional deformation together with the roll freedom. Flutter is found to occur in two basic modes. The first mode is associated with wing bending-aircraft roll coupling and occurs at low values of reduced frequency. The second instability mode closely resembles a classical bending-torsion wing flutter event. This latter mode occurs at much higher reduced frequencies than the first. The occurrence of the bending-roll coupling mode is shown to lead to lower flutter speeds while the bending-torsion mode is associated with higher flutter speeds. The ratio of the wing mass moment of inertia in roll to the fuselage roll moment of inertia is found to be a major factor in the determination of which of the two instabilities is critical.

Abstract: Dynamic model tests were staged to compare the aeroelastic stability of a free-flying oblique-winged aircraft and the known divergent instability characterizing swept-forward wing configurations, to test the effect of wing elasticity on aileron control and trim. The aircraft fuselage was clamped in some tests and left free to roll in others. Two rigid wing panels were hinged near the wing center with elastic restraining springs. It is found that the aeroelastic divergence affecting swept-forward wings does not occur with an oblique wing, whose aeroelastic instability sets in at a dynamic pressure exceeding that for static divergence of swept-forward wings, and appears in the form of undamped oscillations. Oblique wing stability is sensitive to the moment of inertia of the fuselage in roll. Roll control and lateral trim are attainable with conventional ailerons, even at speeds at which divergence of a clamped forward wing shows up.

Abstract: High frequency radiation patterns of aircraft wing mounted antennas are analyzed. Basic antenna types using ray optical techniques are studied. The aircraft is modelled in its most basic form so that this study is applicable to general type aircraft. The fuselage is modelled as a perfectly conducting finite elliptic cylinder. The wings and horizontal and vertical stabilizers are modelled as perfectly conducting "n" sided flat plates that can be arbitrarily attached to the fuselage or to themselves. The antenna locations are assumed to be on the surfaces of the wings at locations removed from engines and stores such that these effects are negligible. Volumetric patterns are calculated for several aircraft. The validity of the solution is shown by comparing the results against scale model measurements. The application of this solution to practical airborne antenna problems has shown its versatility in designing antennas and predicting their radiation patterns in an accurate and efficient manner.

Abstract: A method of effecting recovery of a high speed aircraft from a condition of incipient or developed spin involves, upon entry into the condition, deploying at least one parachute coupled only to the forebody of the aircraft forward of the center of gravity, and is particularly effective in recovering from a flat spin. After recovery, the chute or chutes can be collapsed, released or retracted. The chute is deployed in response to predetermined angle of attack and yaw rate of the aircraft, which may be accomplished automatically under the control of spin condition sensing means. The chute is highly effective because of its location, and hence may be relatively small, the size of the chute, when deployed being such as to have a negligible influence on the free falling rate of sink of the aircraft. The chute or chutes themselves may be conventional, typically of the pilot chute size employed to extract the main chute from a personnel parachute pack, and can be mounted in packed condition on the forebody fuselage or within the fuselage.

Abstract: Considerations of comfort of passengers and crew in light aircraft and helicopters indicate substantial benefits may be obtained by the reduction of interior noise levels. This paper discusses an ongoing research effort to reduce interior noise in such vehicles. Data from both field and laboratory studies for a light aircraft are presented. The laboratory data indicate that structural vibration is an efficient source of interior noise and should be considered in the reduction of interior noise. Flight data taken on a helicopter before and after installation of acoustic treatment demonstrate that over 30 dB of noise reduction can be obtained in certain portions of the spectra. However, subjective evaluations of the treated vehicle indicate that further reductions in interior noise are desirable. An existing interior noise prediction method which was developed for large jet transports was applied to study low-frequency noise in a light aircraft fuselage. The results indicate that improvements in the analytical model may be necessary for the prediction of interior noise of light aircraft.

Abstract: A volumetric pattern analysis of fuselage-mounted airborne antennas at high frequencies was investigated. The primary goal of the investigation was to develop a numerical solution for predicting radiation patterns of airborne antennas in an accurate and efficient manner. An analytical study of airborne antenna pattern problems is presented in which the antenna is mounted on the fuselage near the top or bottom. Since this is a study of general-type commercial aircraft, the aircraft was modeled in its most basic form. The fuselage was assumed to be an infinitely long perfectly conducting elliptic cylinder in its cross-section and a composite elliptic cylinder in its elevation profile. The wing, cockpit, stabilizers (horizontal and vertical) and landing gear are modeled by "N" sided bent or flat plates which can be arbitrarily attached to the fuselage. The volumetric solution developed utilizes two elliptic cylinders, namely, the roll plane and elevation plane models to approximate the principal surface profile (longitudinal and transverse) at the antenna location. With the belt concept and the aid of appropriate coordinate system transformations the solution can be used to predict the volumetric patterns of airborne antennas in an accurate and efficient manner. Applications of this solution to various airborne antenna problems show good agreement with scale model measurements. Extensive data are presented for a microwave landing antenna system.

Abstract: The aerodynamic characteristics of a damaged McDonnell Douglas A-4B aircraft were studied in the Ames Research Center's 40- by 80-Foot Wind Tunnel. A standard fuselage and three different wings were used. The first wing tested was an undamaged one in which holes had been cut and detachable cover plates installed. Removal of one or more cover plates gave one of fourteen different simulated damage cases. The other two wings tested were damaged by actual gunfire at an Air Force range.

Abstract: Tilting the stabilizer at an extreme angle to the fuselage, with leading edge down, and varying engine thrust comprise a method for all-axis control of a generally conventional aircraft in deep stall. In an alternative embodiment, tilting the engines upward at an extreme angle to the fuselage and varying engine thrust comprise a method for all-axis control in deep stall.

Abstract: A detailed analytical study was made to investigate the effects of fuselage cross section (circular and elliptical) and the structural arrangement (integral and nonintegral tanks) on aircraft performance. The vehicle was a 200 passenger, liquid hydrogen fueled Mach 6 transport designed to meet a range goal of 9.26 Mn (5000 NM). A variety of trade studies were conducted in the area of configuration arrangement, structural design, and active cooling design in order to maximize the performance of each of three point design aircraft: (1) circular wing-body with nonintegral tanks, (2) circular wing-body with integral tanks and (3) elliptical blended wing-body with integral tanks. Aircraft range and weight were used as the basis for comparison. The resulting design and performance characteristics show that the blended body integral tank aircraft weights the least and has the greatest range capability, however, producibility and maintainability factors favor nonintegral tank concepts.

Abstract: The results of an experimental study to determine the noise attenuation characteristics of aircraft type fuselage structural panels were presented. Of particular interest was noise attenuation at low frequencies, below the fundamental resonances of the panels. All panels were flightweight structures for transport type aircraft in the 34,050 to 45,400 kg (75,000 to 100,000 pounds) gross weight range. Test data include the results of vibration and acoustic transmission loss tests on seven types of isotropic and orthotropically stiffened, flat and curved panels. The results show that stiffness controlled acoustically integrated structures can provide very high noise reductions at low frequencies without significantly affecting their high frequency noise reduction capabilities.

Abstract: A feed horn mounted within a streamlined enclosure upon the top surface of a wing of an aircraft at an outwardly-spaced location to direct electromagnetic wave energy toward the face surface of a dielectric slim lens having a metallic reflector between the lens and the fuselage of the aircraft to effect a double-traversal of the incident wave energy. The metallic reflector is planar or parabolic to trim the aerodynamic cross section. When the metal skin of the fuselage is used as the reflector, the dielectric constant of the lens is modified by varying its thickness to produce a very sharp beam by compensating for the curvature of the fuselage at the lens support site.

Abstract: Results are presented for wind tunnel tests of an elastic wing model to verify the theoretical predictions for the aeroelastic instability of an oblique wing. The model wing has an elliptic planform of 10 to 1 axis ratio and a symmetrical airfoil section of 7-1/2% thickness/chord ratio. The wing is of wood and as may be seen in the photographs presented, slack wires are used to limit the amplitude of unstable motions. The fuselage is mounted on bearings permitting freedom of roll, but provision is made to clamp the fuselage for some of the tests. It is found that freedom in roll increases the dynamic pressure at which aeroelastic instability first appears. With the model free in roll, the effectiveness of the ailerons in maintaining trim is not noticeably affected by passage through the speed at which the wing would become unstable if clamped.

Abstract: Aircraft having subsonic and supersonic flight capabilities which utilize travelling tail units with circular arc motions, connected with the rear fuselage by means of two arm-frames that swing upward and rearward and vice versa, to generally increase stability and control of aircraft during low-speed flight and to reduce accidents at zero altitude operations.

Abstract: In support of an overall program aimed at minimizing disassembly and reducing inspection time during aircraft maintenance, a series of projects has been carried out to determine the feasibility of applying neutron radiographic techniques to the nondestructive (NDT) inspection of aircraft and aircraft components. These investigations have clearly demonstrated the superiority of neutron radiography over all other NDT techniques in its ability to detect surface and subsurface corrosion in aircraft structure. This capability is particularly significant where the corrosion is hidden behind thick metallic structural members. The neutron radiographic technique hays been applied successfully to detect corrosion in the wing tank of E-2C, C-130, and DC-9 aircraft; rear stabilators of F-4 and F-111 aircraft; aft spar, starboard and port wing, and rudder of the F-8; fuselage skin of the 727; rotary blades of AH-1 and SH-3 helicopters; rotary tail flaps of the UH-2 helicopter; and nose landing gear of A-7 aircraft.

Abstract: A laser beam pointing system, adapted for use in an aircraft. A preferred embodiment of the system includes: a laser beam source, within the aircraft, emitting a laser beam; and, a plurality of laser beam pointing devices in optical alignment with the laser beam. Each pointing device includes: a cylindrical shaped rotatable housing with a window, and either one or two rotatable optical means in optical alignment with the laser beam. One preferred arrangement is the mounting of one pointing device on the upper external surface of the aircraft fuselage, and of another pointing device on the lower external surface of the aircraft fuselage in a location oppositely disposed to and below the other pointing device, with the two pointing devices being in parallel relationship to each other, and with the pointing devices mounted flush with the aerodynamically configurated external surfaces of the fuselage. Another preferred arrangement is the mounting of one of the pointing devices on the leading edge of a left side fairing of the aircraft, and of another pointing device on the leading edge of the right side fairing of the aircraft angularly positioned with respect to the other pointing device, so that their respective axes are in the same plane and the axes would intersect if extended, and with the pointing devices mounted flush with the aerodynamically configurated leading edge of the respective fairings. This inventive system, unlike the prior art, permits the emitted laser beam to be projected over a broad range of angles with little or no aerodynamic interference with the aircraft on which it is mounted and used.