Showing papers on "Landing gear published in 1995"

Aircraft landing-gear drive system

Abstract: The present invention relates to a system for driving the landing gear of an aircraft. An aircraft having wheel driving means associated with at least one of the wheels of the landing gear is described. Preferably, the nose gear is driven, having two wheels (11), both wheels being drivable through a differential gear assembly. Alternatively, the wheel driving means are associated with at least one wheel (41) of each main landing gear assembly. Preferably, a motor (27, 44) powered by the auxiliary power unit of the aircraft is used to drive the wheels of the landing gear. An assembly is also described for driving the wheels (11) of a twin-wheeled nose gear (10) of an aircraft, the assembly comprising an electric or hydraulic motor (27) in operative connection with a differential gear assembly, each wheel being mounted on an axle in forward operative connection with a respective half-shaft (25) of the differential gear through a free wheel mechanism (30).

STOL/VTOL free wing aircraft with improved shock dampening and absorbing means

Abstract: An improved VTOL/STOL free wing aircraft providing damping and absorption of shock landing loads upon landing A pair of resilient struts is provided, projecting forwardly from the trailing edge of either side of the fuselage when the fuselage is tilted Preferably, the aircraft includes a pair of articulated tail booms, the strut being a portion of the tail boom extending forward from the pivot axis of the tail boom Landing wheels are disposed on the strut in tandem spaced relationship The resiliency of the strut causes the strut to act as a leaf spring and thus dampen shock landing loads Operatively secured to the bottom surface of the fixed wing portions and the forward portion of the landing gear struts is a pair of dashpots for absorbing the shock landing loads

Landing gear axle steering

Abstract: A steerable landing gear for an aircraft having a six wheel, three axle (1,9,16) truck has a steerable axle on either the rear (1) or both forward (16) and rear (1) axles of the truck. A set of wheels (17) driven about a vertical shaft (2) utilizes a single actuator (3) and a walking beam (4). The present invention relates to multi-wheel landing gear trucks or bogies for large aircraft and particularly to a method and apparatus for steering a set of wheels.

Landing gear axle steering without walking beam

Abstract: Landing gear axle steering for an aircraft having a six wheel three axle truck. A set of wheels driven about a vertical shaft (2) utilizes a single actuator (3) alone without a walking beam.

Landing gear warning apparatus and method for pilots approaching a runway with retracted landing gear

Abstract: A landing gear warning system for an aircraft with at least one retractable landing gear member comprising: (a) a landing gear indicator adapted for generating a signal representative of the position of the landing gear member; (b) an aircraft positioning system adapted for generating a signal representative of the aircraft's latitude, longitude, and elevation; (c) a pilot warning device; and (d) a computer system operatively coupled to the landing gear indicator, the aircraft positioning system, and the pilot warning device, wherein the computer system includes a database that contains the longitude and latitude, and elevation of a plurality of runways, and wherein the computer system is adapted for receiving the signal representative of the aircraft's latitude, longitude, and elevation, adapted for receiving the signal representative of the position of the landing gear member, and adapted for generating a pilot warning signal that activates the pilot warning device if the aircraft's elevation is less than a predetermined value above the elevation of the closest runway in the database to the aircraft and the signal representative of the position of the landing gear member indicates that the retractable landing gear member is retracted.

Airplane pirouette steering system

Abstract: An airplane steering system which permits 180 degree turns with minimum tire scrub. The system involves steering of both the nose landing gear and the front and rear wheels of both main landing gear each consisting of three inline wheels; thus, the center of turn is placed between the main gears and allows the airplane to make 180 "pirouette" turns.

The NASA landing gear test airplane

Abstract: A tire and landing gear test facility has been developed and incorporated into a Convair 990 aircraft. The system can simulate tire vertical load profiles to 250,000 lb, sideslip angles to 15 degrees, and wheel braking on actual runways. Onboard computers control the preprogrammed test profiles through a feedback loop and also record three axis loads, tire slip angle, and tire condition. The aircraft to date has provided tire force and wear data for the Shuttle Orbiter tire on three different runways and at east and west coast landing sites. This report discusses the role of this facility in complementing existing ground tire and landing gear test facilities, and how this facility can simultaneously simulate the vertical load, tire slip, velocity, and surface for an entire aircraft landing. A description is given of the aircraft as well as the test system. An example of a typical test sequence is presented. Data collection and reduction from this facility are discussed, as well as accuracies of calculated parameters. Validation of the facility through ground and flight tests is presented. Tests to date have shown that this facility can operate at remote sites and gather complete data sets of load, slip, and velocity on actual runway surfaces. The ground and flight tests have led to a successful validation of this test facility.

Symbolic Algebraic Discrete Systems : Applied to the JAS 39 Fighter Aircraft

Abstract: In this document we present symbolic algebraic modeling and analysis techniques applied to the landing gear subsystem in the new Swedish fighter aircraft, JAS 39 Gripen. This is a work in progress r ...

An analysis of ground-flight loads measured on the instrumented b-727 n40.

Abstract: : The Federal Aviation Administration Technical Center owns and operates an instrumented B-727 aircraft for in-house test and assessment of runway friction and to examine landing gear impact on runway surfaces Numerous strain gages were installed on the landing gear Prior analysis of the data was concerned primarily with supporting the FAA's airports research program It was recognized that this data set also has application in correlating the aircraft internal gear loads to measured ground-flight loads for specific takeoff and landing conditions and runway operations This in-house research affords the National Aging Aircraft Research Program an opportunity to assess new data, independently obtained, which is both of high quality and having unusually high sampling rates to examine the landing gear loads for a limited number of takeoff, landing, and ground maneuvers Sixty sample-per-second time history traces were available for each of 72 events with the following breakdown: (1) Takeoff analysis, 22 events; (2) Landing analysis, 18 events; (3) Runway exit analysis, 9 events; (4) Braking analysis, 6 events; (5) S-turn analysis, 9 events; and (6) Minimum-radius turn analysis, 8 events

Landing device for aircraft

Abstract: PURPOSE:To provide a landing device securing a cabin space and preventing damage due to FOD, etc., during ground run. CONSTITUTION:In a landing device for aircraft having a nose landing gear 1 allowed to be housed in a nose landing gear housing space 3 in a front fuselage 2, an operating device 4 for elevating and driving the nose landing gear 1, and a controlling device 6 for ground run for controlling the hose landing gear 1, a pair of side partition members 11 are provided in the nose landing gear housing space 3 at both the sides. The space at the front fuselage 2 is divided into the nose landing gear housing space 3 and right and left side chambers 13. The operating device 4 is provided in one side chamber 13. The controlling device 6 is provided in the other side chamber 13. The operating device 4 and the controlling device 6 are shielded by the side partition members 11 to eliminate damage due to FOD, etc., and are positioned at the nose landing gear 1 sides to sacrifice no cabin space.

Combined Fuzzy-Deterministic Semi-Active Control of a Landing Gear

Abstract: A fuzzy correction of a deterministic semi-active control applied to an aircraft landing gear is presented. An existing computer code has been modified to allow its numerical verification during simulated drop tests and landings. The correction of the control action applied by the fuzzy controller seems to improve the dynamic response by reducing the amplitude of vertical ground load fluctuations.

Landing gear for model airplanes

Abstract: The invention is directed to landing gears for model airplanes. Both the nosegear and the main landing gear are constructed by using an in-line structure having an axial coil spring which is connected to the airplane structure by a shank. The shank is configured to be in-line and generally coaxial with axial coil spring.

Device for door hinge fitting for flying vehicle landing gear leg

Abstract: FIELD: aeronautical engineering. SUBSTANCE: device has landing gear leg 1, door 2 connected rotatably with flying vehicle structure 3 and mechanism 4 which is used as drive for door 2. Landing gear leg is provided with wheels 5. Axes of rotation of leg 1 and door 2 are crossing; points of intersection of their projections on plane of symmetry of flying vehicle and plane perpendicular to it which passes through longitudinal axis of flying vehicle are located in front of wheels 5 of leg 1, thus providing for shift of door 2 forward in extending the landing gear leg. EFFECT: enhanced reliability. 3 dwg

Automatic release and locking of light or ultra light aircraft landing gear

Abstract: Two vertically moving arms (1,2) which are pivoted from the aircraft structure (3,4) carry the wheel axle (5). A metallic coiled spring (7) is mounted between the junction point of the two arms and a reinforcing point (8) of the aircraft structure. The arms are held in their low position by the spring compression force which opposes landing gear closing forces arising from landing and rolling. There is a gas shock absorber at the upper part of the spring. The landing gear is raised by a traction rod (10) acting at the junction point of the arms. This rod generates a pull which tips the arms as well as a force perpendicular to the major axis of the spring through a projection (11). This causes buckling and bending of the spring and its complete refolding.

Open-Loop/Closed-Loop Control Simulation on the Stability of a Landing Gear Undergoing Overrun Braking

Abstract: The antiskid braking system (ABS) of a landing gear of aircraft is one of the operating system which can guarantee an aircraft to taxi along the runway in safety. The ABS consists of wheel-speed sensor, antiskid braking controller and brake. As the output of ABS, the braking moment will directly influence both the braking efficiency and the taxiing stability of aircraft. The existing experimental results show that during the taxiing and braking operations of aircraft along the runway, overrun braking will not only make the wheel lock, tyre wear seriously, but also result in a marked drop in the taxiing stability of aircraft. For this reason, based on the viewpoint of the mechanical principle combined with the nonlinear control theory, we develop the open-loop/closed-loop control simulation on the dynamic properties and the taxiing stability of landing gear by numerical integral method. In this paper, we demonstrate and analyze the slipping phase-plane trajectories of a wheel and tyre under braking. In order for ABS to promote the braking efficiency and guarantee antiskid automatically, we present the variable structural control of braking moment and express the analytical conditions that the braking moment should be satisfied. Through dynamic simulations, we discuss the dynamic properties of main landing gear under taxiing and braking along the runway.