Showing papers on "Landing gear published in 1973"

Landing gear wheel device for aircraft

Abstract: A landing gear device for an aircraft including a landing gear having a landing wheel rotatively mounted thereon and a variable speed motor for selectively engaging the wheel and rotating the same, at a selectable speed in the forward direction during the flight of the aircraft preparatory to the landing of the aircraft, reciprocal drive element, operably interconnecting the motor to the landing wheel adapted to engage the wheel and rotate the wheel when power is applied to the electrical motor, and adapted to disengage from the wheel to permit free rotation thereof when the motor is deenergized, and speed control element, connected to the motor for substantially synchronizing the rotational speed of the landing wheel to that of the landing speed of the aircraft.

Landing gear for stol airplanes

Abstract: An airplane main landing gear is designed to provide abnormally high ground clearance at touchdown, for minimum ground effect and maximum nose-down angle, and then to slowly sink to normal ground clearance during the landing roll. This gear may be contracted to lower or ''''kneel'''' the airplane. In addition, differential lengthening of left and right gears is provided to permit the airplane to land in a banked attitude for crosswind landings, thereby obviating the necessity to fully straighten-out the airplane before touchdown during such operations. The latter feature also provides a crosswind gear which is operationally less complicated than conventional crosswind gears which necessitate turning/steering all gears or wheels.

Landing wheel rotating device for aircraft

Abstract: A power operated device associated with the conventional landing gear of an aircraft for causing rotation of the landing wheels of the aircraft by the air-stream moving past the aircraft prior to landing and while still airborne.

Main landing gear

Abstract: A main landing gear for helicopters and the like includes a pivotal oleo strut having a cylinder and projecting piston rod, a tire mounted on the free end of the piston rod, and a linkage assembly for controlling the extension of the piston rod according to the pivotal position of the oleo strut relative to the fuselage, whereby the ground engagement portion of the tire tread is maintained in a substantially vertical plane of fixed lateral distance from the helicopter fuselage during all landing and support modes of the landing gear. In two embodiments of the invention, the tire is mounted on a wheel support that is pivotally controlled by the linkage assembly during landing gear retraction to throw the mid circumferential plane of the tire into an orientation substantially parallel to the axis of the oleo strut.

Analysis of Legged Landers for the Survivable Soft Landing of Instrument Payloads

Abstract: Two methods of analysis were developed for legged planetary landers. These consist of a LargeDisplacement Gear Analysis and a Landing Dynamics Analysis. The Large-Displacement Gear Analysis is employed to determine the large-displacement stroking behavior and energy absorption characteristics of a typical gear. The spatial landing dynamics of a legged lander is predicted through the Landing Dynamics Analysis. Effects of structural flexibility and elastic-plastic gear load characteristics on loads and motions of the lander are determined. Validation of the analytical techniques employed in the Landing Dynamics Analysis is accomplished through comparison of predicted results and experimental data obtained during a model test program.

In-flight retractible landing gear training simulator for fixed landing gear aircraft

Abstract: When a pilot, fully qualified and licensed, and possibly of long accident-free experience, in the flying of fixed landing gear aircraft, desires to progress to retractible landing gear aircraft, the insurance companies require extensive flight practice with an instructor as a condition precedent to the issuance of a required insurance policy. The present invention provides a simple, compact, inexpensive simulator for installation on fixed landing gear aircraft, having (1) a manually operable actuator corresponding to the landing gear lowering actuator provided conventionally on rectractible landing gear aircraft, (2) indicator means responsive thereto for randomly simulating either correct lowering and locking of the individual landing wheels or a malfunction of one or more of the landing wheels, and (3) means corresponding to a conventional emergency landing gear lowering actuator for cancelling any indication or indications of malfunction. The simulator further includes a sounding device and a warning light for reminding the pilot that he has overlooked "lowering the landing gear" whenever he has cut the throttle without having gone through the landing gear lowering procedure, and for calling attention to the fact that not all landing gear lights are lighted when they should be.

Experimental validation of a landing-dynamics computer program for legged spacecraft landers

Abstract: Validation of a landing-dynamics computer program has been accomplished by comparing analytical data with data from a limited experimental program. Agreement obtained established the subject landing-dynamics computer program as a reliable design tool for legged spacecraft landers.

Landing gear for semi-trailer

Abstract: A landing gear for semi-trailers comprising a generally pieshaped landing pad, including an upper bearing of suitable size to readily pivotally affix to the existing landing gear axle. The landing pad includes a forward rise portion which terminates in a curved cam surface which acts as a cam when the trailer is either moved forwardly or rearwardly by a tractor. The arcuate portion terminates rearwardly in a flat, weight sustaining, support section of sufficient length to provide a stable surface to carry the weight of the semi-trailer. A spring biases between portions of the semi-trailer and the landing pad in a manner to continuously urge the landing pad rotatively about the axle to a position clear of the ground.

V/STOL tilt rotor aircraft study mathematical model for a real time simulation of a tilt rotor aircraft (Boeing Vertol Model 222), volume 8

Abstract: A mathematical model for a real time simulation of a tilt rotor aircraft was developed. The mathematical model is used for evaluating aircraft performance and handling qualities. The model is based on an eleven degree of freedom total force representation. The rotor is treated as a point source of forces and moments with appropriate response time lags and actuator dynamics. The aerodynamics of the wing, tail, rotors, landing gear, and fuselage are included.

Crashworthy Landing Gear Study

Abstract: : The purpose of the reported effort was twofold: to develop rotary- wing landing gear concepts and criteria which, when applied, would lessen the magnitude of crash forces transferred to occupiable areas of helicopters involved in severe yet survivable accidents; to use the concepts and criteria to design, fabricate, and test an experimental prototype skid landing gear system. Landing gear design criteria, crash criteria, energy-absorbing design criteria, and applicable specifications were collected and analyzed to establish the state of the art in the landing gear design and energy absorber design. Once this was accomplished, the data were used to develop preliminary design criteria and concepts for three classes of rotary-wing aircraft. The concepts were selected to be compatible with combined loads and various attitudes.

Experimental investigation of the cornering of a C40 x 14-21 cantilever aircraft tire

Abstract: An experimental investigation was conducted at the Langley aircraft landing loads and traction facility to define the cornering characteristics of a size C40 x14-21 aircraft tire of cantilever design. These characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained for the tire operating on dry, damp, and flooded runway surfaces over a range of yaw angles from 0 deg to 20 deg and at ground speeds of 5 to 100 knots, both with and without braking. The results of this investigation show that the cornering-force and drag-force friction coefficients and self-alining torque were influenced by the yaw angle, ground speed, brake torque, surface wetness, and the locked-wheel condition.

Model Study of C-5A Landings on AM2 Landing Mat

Abstract: : After a buckling failure in a section of AM2 landing mat runway during a test landing of a C-5A at Dyess AFB, Texas, in August 1970, a model testing program was initiated. This report presents the results of the development and testing of an analytical model and a 1/7-scale physical model AM2 mat runway subjected to C-5A loadings. The analytical model represents the landing mat as a series of discrete rigid elements interconnected and suspended by springs and dashpots subjected to external forces simulating Coulomb friction, shear, and the action of the aircraft. Results from the computer program developed included a simulation of the Dyess failure and an evaluation of various mat modifications. The 1/7-scale physical model of the C-5A landing gear produced buckling failures in the model AM2 mat runway similar to the failure that occurred at Dyess AFB.

STOL Tactical Aircraft Investigation. Volume VI. Air Cushion and Ground Mobility Study.

Abstract: : The tactical STOL transport design must consider forms of high flotation landing gear to operate effectively from unprepared fields One configuration of particular interest is the Air Cushion Landing System (ACLS) which utilizes the ground effect principle to reduce ground overpressures The configuration includes a rubber-nylon, torus-shaped trunk attached to the lower portion of the fuselage Air is supplied to the trunk by turboshaft-driven fans It is then exhausted through rows of holes along the trunk ground tangent Aircraft weight is distributed over the cushion area providing the desired low ground pressure After liftoff, the trunk is deflated and retracts into the side of fuselage by elastic action of the trunk material Braking is accomplished by expanding inflatable pillows against the ground mobility and bleeding off cushion pressure The cargo delivery/loading capability of the MST can be greatly expedited by incorporating an onboard ground mobility system in conjunction with conventional landing gear After viewing various wheel drive systems (pneumatic, electrical, hydraulic), a mechanical drive system is presented A gas turbine APU is mounted to the shock strut over each bogie, driving the wheels through reversing gear, clutch and shafting

STOL Tactical Aircraft Investigation. Volume VI. Air Cushion Landing System Study

Abstract: : Analyses and design studies have been conducted to determine the characteristics of an Air Cushion Landing System (ACLS) as it would be applied to an Advanced Medium STOL Transport (AMST) equipped with mechanical flaps and a vectored thrust powered lift system. It was determined that an ACLS would be feasible on an AMST type airplane, but requires a special housing arrangement which broadens the ACLS footprint area when it is deployed. Furthermore, special provisions are needed for ground handling and parking. Because it eliminates some of the concentrated loads associated with conventional landing gear, and is easily faired for low drag when retracted, the ACLS would permit a noticeable reduction in aircraft empty weight for a given mission requirement, if structural provisions for conventional landing gear are not included in the airframe. Substantial uncertainties remain unresolved especially with respect to aircraft/air cushion landing dynamics and spray/debris effects.

Low Speed Aerodynamic Characteristics of an A-4 Aircraft with an Air Cushion Landing System

Abstract: : The effect of a twin trunk air cushion landing gear system on the stability and control of an A-4 type aircraft was evaluated through an exploratory wind tunnel program. The active air cushion in ground effect conditions was found to reduce both drag and the static margin and markedly degrade the directional stability characteristics of the 22 percent scale wind tunnel model. However, the modified aircraft retains adequate longitudinal stability and both the flaps and stabilizer controls are effective and adequate for trimming the aircraft.

Graphite Composite Landing Gear Components - Side Brace Assembly and Torque Link for A37B Aircraft.

Abstract: : A discussion is presented on graphite composite landing gear components. The design, fabrication, and testing of three separate components of the main landing gear for A37B aircraft are investigated. Specifically, the upper side brace, lower side brace, and torque arm are involved. Designs of point loaded graphite/epoxy composite landing gear components along with their fabrication, including the use of chopped graphite/epoxy curing molds, are presented. It is demonstrated that complex components can be fabricated using chopped and continuous graphite/epoxy to withstand the static and fatigue loads encountered by the production metal components in service. Component weight savings as great as 50 percent have been achieved under this contract. (Author, modified-PL)

Aircraft Antiskid Analysis Verification and Refinement

Abstract: : A program for verifying and refining a previously developed aircraft antiskid performance and system compatibility analysis procedure is described. Analysis verification was performed by comparing antiskid system operation as predicted by the analytical procedures with that recorded during laboratory testing. The laboratory tests were conducted at the Air Force Flight Dynamics Laboratory Landing Gear Test Facility at Wright-Patterson Air Force Base, Ohio using a set-up consisting of F-111 aircraft main landing gear, tire, wheel, brake, hydraulic brake actuation system and several antiskid control circuit variations.

Simulation of the Compatibility of an Air Capable Ship and a VTOL Aircraft

Abstract: : An interactive computer simulation, LARC-I, has been designed to solve the non-linear equations of motion of a generalized VTOL aircraft taking off from or landing on the deck of a ship moving in an irregular or random seaway. This version of LARC-I is limited to longitudinal motions, but is designed for eventual expansion to all degrees of freedom. The LARC-I programs makes use of ship motion amplitudes and frequencies derived separately in a ship motions program, wherein the forcing functions of the seaway are based on a stochastic representation of the waves for any given sea state. The pitching and heaving motions of the ship are transmitted to the aircraft by a realistic simulation of the landing gear. (Modified author abstract)

Conceptual Design of an Air Cushion Landing System for an Unmanned Aircraft.

Abstract: : The problems associated with existing recovery systems include difficulty in mid-air retrieval of RPV's in excess of 1500 lbs; high operations and support costs of parachutes, recovery helicopters, other aircraft and their crews; long recycle time; paving quality requirements for wheeled or skid type landing gear; and frequent damage of RPV's recovered by parachute/attenuation bag or parachute/mid-air recovery systems. Accordingly, this preliminary design study report describes an air cushion landing system (ACLS) applied to the 3,000 lb Jindivik Mk 3A unmanned aircraft. The ACLS is stowed for cruise flight in a clean aerodynamic fairing on the underfuselage, resulting in a minimum performance degradation. For recovery, hinged clam-shell type doors are unlatched, and open, permitting inflation/deployment of an inelastic type elongated toroid-shaped trunk. The trunk is inflated and blown with bleed air tapped off an existing port on the Jindivik's Viper Mk 201 engine. After landing, the aircraft is placed on a fixture and the trunk is manually restowed in the fairing. (Modified author abstract)