Showing papers on "Landing gear published in 1993"

Aircraft weight and center of gravity indicator.

Abstract: An onboard system for use in measuring, computing and displaying the weight and center-of-gravity for aircraft, while keeping aircraft movement to a minimum. Pressure sensors are mounted in relation to each of the landing gear struts. An onboard pump and reservoirs are attached to each of the landing gear struts and are activated by a computer/controller, while landing gear strut pressures are monitored in the determination of strut stiction. The computer/controller calculates the stiction of each landing gear strut and compensates for the pressure distortions caused by landing gear strut stiction. Additional features include reducing strut stiction, measuring landing gear strut fluid levels, monitoring landing gear strut health, weight adjustments for external ice and de-icing fluids, weight adjustments for wind, monitoring aircraft landing gear strut movement.

Landing gear assembly for airplane

Abstract: A nose landing gear assembly on an airplane with a front fuselage section having a wheel bay defined therein and a pair of laterally spaced side compartments defined therein on each side of the wheel bay by respective laterally spaced side walls. A nose landing gear is mounted on the fuselage section for pivotal lifting and lowering movement into and out of the wheel bay. The nose landing gear assembly includes an actuator disposed in one of the side compartments for lifting the nose landing gear into and lowering the nose landing gear out of the wheel bay, and a steering device disposed in the other of the side compartments for steering the nose landing gear while the airplane is taxiing. Since the actuator and the steering device are concealed in the respective side compartments, they are protected from foreign-object damage. The nose landing gear assembly allows the airplane cabin to have increased space because the actuator and the steering device are positioned laterally of the nose landing gear.

An electrorheologically controlled semi-active landing gear

Abstract: This study is to explore the application of electrorheology (ER) to the real-time control of damping forces that are transmitted through the nose landing gear for an F-106B aircraft The main part of the landing gear is a strut that consists of a pneumatic spring and an ER controlled damper that is situatted on the strut centerline and applies a force directly opposing the vertical displacement of the nose wheel The damping element rotates in response to strut displacement, employing a co-axial arrangement of stator and rotor plates connected to the opposing electrodes in the control circuit The vertical displacement is conveted into rotation of the damper through a screw-nut mechanism The ER fluid between the electrodes is thus engaged in shear along circumferential lines of action This design results in a fast time response and a high ratio of strut forces achieved under Er-vs zero-field control Compact size and simplicity in fabrication are also attained The analysis shows that when using an ER fluid of a yield stress of 7kPa, the energy absorption efficiency of the landing gear can reach almost 100% at various sink rates

An Analysis of a Civil Aircraft Main Gear Shimmy Failure

Abstract: A dynamical model is presented to analyse the stability of motion of the two-wheeled ‘Fokker F.28-like’ landing gear including tyres. The model is equally applicable to similar landing gears. The influence of the introduction of a specially designed torsional damper on the dynamical behaviour of the landing gear-tyre combination is investigated. Results of the stability calculations are supported by test results.

Low-cost shuttle-derived space station

Abstract: The space station of the present invention makes use of a modified space shuttle orbiter vehicle to provide a pre-assembled pre-tested, modular space station. The modified orbiter vehicle has all the equipment need for manned launch, re-entry and landing removed. The modified orbiter vehicle carries a pressurized laboratory module, a solar power system, and docking apparatus. The modified orbiter vehicle provides instrumentation, attitude control, communications, and life support systems. Another configuration includes an external fuel tank permanently attached to the modified orbiter vehicle. In either configuration, all equipment is fully integrated, installed and checked out on the ground before the launch in a single unmanned launch. Since the modified orbiter vehicle remains in space as a part of the space station the complexity and weight of the orbiter can be reduced by removing the systems that are required only for manned ascent, re-entry and landing, such as wings, tail, body flap, thermal protection tiles, landing gear, some of the avionics, some crew related controls, displays and hardware.

Auxiliary control of aircraft landing gear movement

Abstract: Auxiliary control of extension, retraction and pivotal movement of aircraft landing gear when not in use is provided by a method of operation, apparatus for attaching to the landing gear, and an assembly comprising landing gear and apparatus. The apparatus comprises auxiliary jacking means (18, 19) attachable between relatively telescopic parts of an oleo main strut of the landing gear and between relatively pivotal parts of the oleo and of a bogie pivotally attached to a lower end of the oleo. The landing gear may thus be powered up by the auxiliary jacking means (18, 19) with the pivotal movement of the bogie (4) being controlled simultaneously during, e.g. removal, fitting or servicing of the landing gear.

Pneumatic trailer landing gear

Abstract: A pneumatic actuator for a trailer landing gear reduction assembly for directing the raising or lowering of the feet of a trailer The pneumatic actuator replaces the hand crank which has traditionally been used for turning a gear reduction assembly of the trailer The present invention can be incorporated onto the already existing trailer landing gear or the present invention can be milled directly onto the newly manufactured trailer

An aircraft landing gear trolley

Abstract: An aircraft landing gear trolley (1) for supporting a landing gear (2) and adjusting the position of pintle bearings (39, 71) thereof in relation to pintle mountings on an aircraft is provided. The trolley (1) includes a rolling chassis (3) and a number of frames (15, 16, 17, 18, 19) nested therein, each arranged to provide a different degree of freedom for the landing gear (2). The said degrees of freedom include movement along horizontal, longitudinal and transverse axes, raising and lowering movement and rotational movement about horizontal and substantially upright axes. The rotational axes are coincident at a point positioned centrally of one of the pintle bearings (39) of landing gear (2) supported by the trolley.

Towing vehicle for aircraft

Abstract: The invention relates to an aircraft towing vehicle, comprising a lifting and a locking device (5) for the nose landing gear of the aircraft being towed, which device has two support elements (9) which reach behind the nose wheels and can be displaced along straight-line guiding rails (15) by means of a linear drive (11) so as to pull the nose wheels of the aircraft onto a lifting platform (7) and to lock it into place thereon. At the end of each guiding rail (15), the invention provides for a guiding pin (29) which, in cooperation with a guiding track (31, 31') embodied in the support element, controls the rotation of said support elements into a release position in which the nose landing gear is able to pass through or, by a reverse movement, the rotation of the support elements into the operating position in which said support elements reach behind the nose landing gear.

Soft-Ground Arresting System for Commercial Aircraft

Abstract: : A soft-ground arresting system provides an economical and nondestructive means for decelerating an aircraft that would otherwise be unable to stop safely within the confines of the runway including the safety or overrun area. This report validates a mathematical model developed to predict deceleration of an aircraft as it travels through a soft-ground arresting system. Full-scale tests were conducted at the Federal Aviation Administration Technical Center using the FAA's instrumented B-727 aircraft. The speed of the aircraft entering the beds ranged from 20 to 80 knots. The dimensions of the bed were as follows: foam thickness range was from 6 to 18 inches; test bed length was from 88 to 176 feet; width was always 40 feet. In each test the deceleration experienced by the aircraft was recorded in addition to its velocity, landing gear loads, and brake torque. The results of these tests showed that actual measured parameters from the aircraft were within 10 percent of the values predicted by the mathematical model; thus validating the accuracy of this model. The 18-inch-thick foam bed provided the most effective deceleration without exceeding the stresses encountered by the aircraft during normal operation. Fire and rescue equipment can maneuver and conduct emergency operations within the foam arrestor bed without difficulty.

Ground proximity warning system for non-retractable landing gear aircraft

Abstract: A ground proximity warning system and a detector for aircraft having fixed or non-retractable landing gear which rather accurately detects a landing phase of flight in order to adjust the warning envelope to minimize nuisance warnings during such a phase of flight. In particular, the system monitors the flap position to provide an indication to the ground proximity warning system that the aircraft is either in an approach, cruise or landing phase of flight. Cams mounted to the air flaps system indicate a landing phase of flight when the approach flaps are configured for a normal landing, such as 16°-18° flaps or an approach phase of flight when the flaps are configured for a normal approach, for example, 5°-7° flaps. By providing a relatively accurate indication of the phase of flight for an aircraft with non-retractable landing gear, nuisance alarms will be virtually eliminated, while maximum protection is provided during all phases of flight.

Computer Modelling of Aircraft Hydraulic Systems Using Bathfp

Abstract: The computer simulation package BATHfp has been developed at the Fluid Power Centre, University of Bath to perform transient time domain simulations of fluid power systems. Utilities are provided which allow new models to be introduced into the component database. This enables the package to be tailored to particular dedicated areas of interest such as aircraft flight controls, braking and landing gear and fuel flow systems. This paper describes the application of BATHfp to aircraft hydraulic systems. An example is taken of an electrohydraulic position control system which uses an actuator to move an aileron according to a desired schedule. Parametric variations are made to illustrate how system performance can be improved.

Raisable landing gear

Abstract: The invention relates to raisable landing gear having a shock absorber strut and a sliding rod. According to the invention, the landing gear includes a lateral stabilizer hinged to the strut and fitted with a wheel at its free end, together with mechanical coupling means associated with said lateral stabilizer, in such a manner that: firstly lowering the landing gear deploys the lateral stabilizer so that its wheel, when the landing gear is in its lowered position, provides support additional to that provided by the wheels of the wheel set, and also constitutes a lateral stabilizer proper during taxiing of the airplane; and secondly raising the landing gear folds the lateral stabilizer so as to enable the entire landing gear assembly to be housed when in the raised position. It then becomes possible to organize the landing gear beneath the fuselage of the airplane, thereby making it possible to obtain landing gear that is extremely short.

Vehicule for ground escort of aircraft

Abstract: Vehicule for ground escort of aircraft in an airport. The vehicule comprises a wheeled structure (11) shaped and sized so as to be received under the aircraft (16) and having two loading plateforms (24) for the main landing gear and a loading platform (26) for the front landing gear. The two loading platforms (24) are fitted with locking mechanisms for the main landing gear so that acceleration and deceleration forces are supported by the main landing gear.

Wheel of aircraft

Abstract: PURPOSE: To greatly reduce the amount of consumption of jet fuel during ground running of an aircraft by rotating wheels for takeoff and landing by using power from a power source for ground running, which consists of an engine or electric motor installed in an engine room in the lower part of an airframe, and making the aircraft travel on the ground while reducing the rotation of a jet engine to the minimum or stopping it during ground running from a boarding point to a takeoff start line. CONSTITUTION: The main landing gear 1 of an aircraft is composed of a power source for ground running, which is installed in an engine room in the lower part of an airframe, a strut 20 provided with a rotary shaft 21, a rotationally driving mechanism 22 which transmits power from the power source to the rotary shaft 21, a wheel main shaft 30 which receives the transmitted power through the rotary shaft 21 to be rotationally driven, a wheel 33 which is mounted to transmit or turn off the rotational driving power of the wheel main shaft 30 through a clutch 31 and a clutch gear 32.

Airplane and the way of its transforming to parking position

Abstract: This invention belongs to aeronautical engineering sphere, particularly to two and three seat airplanes of tourist class, which can be used besides for training and sanitary purposes as well. The achieved technical result of this invention - is the simplification of the airframe, reduction of weight, the simplification of the airplane control, the improvement of the cockpit vision, the opportunity of landing gear modification change. If the airplane is transformed to parking position - it is the minimizing of overall dimensions and the preservation of the essential members of the airframe against all possible mechanical damage during the transportation. The airplane containes the fuselage with the cockpit 1, power plant ( which includes engine 4 and tractor propeller 5 ), tricycle landing gear with nose 6 and main 7,8 landing gear legs, and the V - tail of standard lay - out. The fuselage framework consists of four flat frames 10,11,12 and 13, lower load - bearing platform 14, four constrained beams 15,16,17 and 18, main frame 20 and fuselage tube 19. The constrained beams are rigidly connected to the fuselage tube 19 by the main frame 20 at its corners, as well as to the back flat frame 13, also at its corners. Each of the outboard wing panels 22 is fulfilled turning around on its hing unit and can be folded backward along the airplane axis. The load - bearing platform 14 is equipped with the spring attachment points 25 and 26 of the main landing gear legs 7 and 8 at the airplane configuration accordingly with tailwheel unit and nose gear leg. The wing strut 9 attachment point to the wing 22 spar 23 lies within the range 0,3 ÷ 0,4 of wing semispan.

Aircraft nose gear shimmy studies

Abstract: An overview of previous studies involving aircraft nose gear shimmy behavior is given together with some test results identifying the influence of different factors inducing shimmy. A NASA Langley test program conducted at the Landing Loads Track (LLT) facility to evaluate shimmy characteristics of an actual Space Shuttle nose gear is described together with some of the test results. Based on results from these various evaluations, recommendations are made concerning nose gear design features, such as corotating wheels, to minimize the occurence of shimmy.

A numerical study of airplanes flying in proximity

Abstract: : During an emergency such as an unsafe landing gear indication, a second aircraft is often used to perform an airborne visual inspection of the landing gear. The chase airplane may be quite dissimilar in size and wing loading and consequently experience unexpected aerodynamic forces and moments caused by the other airplane. A numerical study of the inherent danger involved with the aerodynamic interaction of aircraft flying in proximity was made using the low-order panel code PMARC (Panel Method Ames Research Center). PMARC validation was made by comparing wind tunnel and analytically derived stability data for T-34 and F-14 models with PMARC results. A T-34 was then placed at various distances underneath an F-14 to determine changes in lift and pitching moments on the T-34. Color illustrations of pressure coefficients were used to highlight the changes in aerodynamic forces and moments as vertical separation between the two aircraft was decreased. PMARC showed that 4.5 deg. of elevator trim change were required as a T-34 approached to within its semispan of an F- 14.

A320 crash spurs lufthansa action.

Abstract: 8 ASUBTITLE: IN THE WAKE OF A FATAL RUNWAY OVERRUN, LUFTHANSA AND AIRBUS DISAGREE ON A320 LANDING PROCEDURES, AND THE CARRIER ORDERS LANDING GEAR MODIFICATIONS.

Landing device for semitrailer

Abstract: PURPOSE: To construct a two speed double reduction gear assembly with fewer parts so as to have a simple structure and be compact in size, and accommodate the assembly substantially in a landing gear leg. CONSTITUTION: The semitrailer is provided, at the front end thereof, with first and second upright and telescopically extensible legs 11 with an interval therebetween in a transverse direction, and an input shaft 75 and an output shaft 42 which are transversely and rotatably disposed on the first leg, the output shaft being connected to an input shaft of the second leg. There is also provided a gear means located substantially adjacent to the individual input and output shafts to operate a landing device in either a high or low gear position, in which when a gear means of the input and output shafts of the first leg is switched to a low position, the ratio of the revolution of the input shaft to a vertically travel distance of both legs is from about 15 to about 50, and when switched to a high position, the ratio is from about 2 to about 5.

Design of an airborne launch vehicle for an air launched space booster

Abstract: A conceptual design is presented for a carrier vehicle for an air launched space booster. This airplane is capable of carrying a 500,000 pound satellite launch system to an altitude over 40,000 feet for launch. The airplane features a twin fuselage configuration for improved payload and landing gear integration, a high aspect ratio wing for maneuverability at altitude, and is powered by six General Electric GE-90 engines. The analysis methods used and the systems employed in the airplane are discussed. Launch costs are expected to be competitive with existing launch systems.

Parametric identification of an aircraft landing gear damper, by means of periodic excitation

Abstract: Identification of nonlinear dynamical systems is most often performed by application of transient measurement signals, which are chosen in a way to re- semble actual or future trajectories of the system under consideration. Another approach, analog to the experimental analysis of linear systems, is application and measurement of periodic loads in order to measure the corresponding periodic equilibrium solutions and/or outputs. This new technique, using a Bayesian estimator will be illustrated with axial measurements on a nose landing gear damper under periodic excitation. Good results were obtained for identifications on a single frequency and amplitude, but the predictive power in other parts of the parameter or state space is low.

Baggage or freight hold with aerodynamic lines which are suitable for reducing the drag "CX", forming a fairing for the main landing-gear bay under the fuselage of aircraft

Abstract: Baggage or freight hold device for an aircraft with landing gear under the fuselage, the device combines the volume necessary for a fairing by extending the aerodynamic lines of the gear bay (1) with a part of the volume available under the cabin floor, obtained by a reduction in the curvature of the fuselage bottom frames (7), the fairing hold assembly (2) is stiffened longitudinally by a central panel forming a beam (9) Preformed panels (11) each incorporating an access with a shield-shaped door (12) are fixed onto the main frames (3) (4) (5) on the central panel (9) and along a ledge (10) which longitudinally fixes the upper shape of the hold (2), a flap (15) loaded by a spring sets the pressure level in the fairing hold which is temperature-controlled by a flow of cabin air calibrated through an orifice This device is particularly suitable for releasing baggage hold space in the cabin of aircraft equipped with a landing gear under the fuselage and requiring an aerodynamic fairing

Retractable landing-gear, in particular for wide-body aircraft

Abstract: The invention relates to a retractable landing gear including an articulated leg (100) and an associated cross-bracing means (140). In accordance with the invention, the landing gear is of the leg-shortening type, and the cross-bracing means are produced in the form of a fold-away strut (140) the lower arm (143) of which is articulated to the lower extremity of the sliding rod (103) of the articulated leg (100), the said strut furthermore being arranged in such a way that, in gear-down position, the lowered leg is inclined towards the front of the aircraft.