Abstract: An unmanned aircraft of the remotely piloted type that is characterized by its configuration and outline using rigid counter rotating propellers, positioned substantially at the height of its center of mass or slightly below to allow producing a sufficiently large control moment to use a tether line for landing the aircraft and to allow using two substantially spheroidal surfaces at the top and bottom respectively rather than a single one relatively larger and more detectable surface as when the propellers are at the top.

Abstract: A fluid tight closure for an aperture, more particularly adapted to form a fuel tank access door for an aircraft, preferably made of composite material and providing fail-safe features and resistance to lightning strikes; and further characterized by its light weight, relatively low cost of manufacture, and flexibility to bend from a flat to a curved configuration defined by the curvature of a wing. This fluid tight closure comprises an inner door panel and an outer door panel having each a rim portion complementarily shaped relative to each other and to the edge portion of an aperture, and clamping against the opposite sides of the edge portion with an interposed sealing ring and with nuts and screws sealingly extending through the rim portion and holding the same in clamping position.

Abstract: A railway truck assembly adapted to produce steering of the wheel axles radially to a curve independently of mere lateral motions of the car body to reduce wear and noise and also featuring a pivot connection between the bolster and the truck frame elements which; in cooperation with direct transmission of the load to the truck frame through the opposite ends of the bolster, allows to use a relatively thinner and centrally non-bulging bolster. Thus, more space is made available between the central portion of the bolster and the top of the rails; which space is advantageously used to install some equipment such as for instance a linear induction motor or LIM.

Abstract: A stereoscopic viewer adapted to view the images of a panoramic camera film in particular without having to cut and position the image frames side by side and while also readily compensating for the variation in physical separation between points at the center and at the edge of the images frames.

Abstract: A gyroscopic azimuth aiming concept adapted to aim a navigable body such as a drone or missile before its launching and defining an aiming method and system, and a suspension system to pendulously and removably suspend a gyroscope unit from the navigable body such that the gyroscope unit is isolated against pitch and roll displacements to be sensitive only to azimuth deviation of the navigable body. The aiming system and suspension system include a suspension assembly having an upper end removably connectable to the navigable body, a lower end, cables pendulously suspending the lower end from the upper end, and an anchoring base with an upright pivot to laterally restrain the lower end while allowing horizontal pendulous rotation and pivoting thereof, and a gyroscope unit is pendulously suspended to the lower end and its input axis is approximately aligned in the East direction to measure its azimuth deviation from the East direction by the effect of the earth rotation thereon.

Abstract: A skin welded joint comprising a thin metallic skin welded to a metallic frame member such as a metallic post or beam such as to substantially avoid local distortion, discoloration, and/or physical degradation of the skin and the resultant loss of appearance and/or strength. This skin welded joint comprises an elongated frame member, such as a post or beam, including one flange adjacent the skin, laterally spaced apart ribs projecting from one side of the flange and in contact with the skin, and a pair of flange portions integrally extruded with the ribs and the remainder of the elongated frame member. The flange portions laterally project on opposite sides of the flange, have a reduced thickness relative to the flange, for readily deformation under the heat of welding, and are welded to the skin.

Abstract: A powder and water mixing system which is operatively mounted onboard an aircraft and uses water scooping to automatically produce onboard mixing of powder and water. This system is particularly adapted to drop a fire retardant powder and water mixture from a flying aircraft and includes a pair of tanks, powder containers fore and aft of the tanks, water scoops projecting from the bottom of the aircraft, a pair of powder injection and powder and water mixing devices connected each to a tank, to a water scoop, and to a group of powder containers, a powder container selection valve interposed between each injection and mixing device and the corresponding group of powder containers, and a control connected to each selection valve and arranged to empty a powder container forward of the tanks concurrently with a powder container aft of the tanks, sequentially with water scooping passes by the aircraft.

Abstract: A system consisting of a door closure and door hanger which are integrated to achieve improved operation and simple construction and particularly characterized by a single action pneumatic cylinder and an internal return spring coiled around the piston rod to achieve pneumatic opening of the sliding doors and spring closing of the latter respectively in combination with novel track units featuring removing the load on the balls when the doors are in closed position and shorter track units less subject to longitudinal deflection of the passenger vehicle. The return spring is taken advantage of to produce unhurting impact and closure force at the end of the closing course and to eliminate the sealing requirements around the piston rod at the corresponding end of the pneumatic cylinder.

Abstract: A sliding doors and seals system and a passenger vehicle having such system with the latter including inflatable seals and weather seals arranged to conceal and protect the inflatable seals against direct and even indirect contamination and tampering therewith and such as to provide a failsafe feature whereby a pair of sliding doors will be frictionally retained closed by one inflatable seal alone upon failure of the other inflatable seal.

Abstract: A skin construction positioned at the junction of a side wall with the roof of a passenger vehicle such as a railway passenger car, made of a simple extruded cant rail and a simple extruded side cover which are characterized by concealed attachment to the car body, readily removable attachment one to the other, and by a roof gutter in addition to an eaves drop gutter to be efficient against the worst weather conditions such as heavy and freezing rain and melting snow. The cant rail forms a roof gutter along the upper longitudinal edge thereof, the side cover forms an eaves drop gutter along the upper longitudinal edge thereof and is spaced from the side of the car to produce a longitudinal door closure and hanger space, the cant rail and side cover form a downward and an upward attachment flanges respectively which are removably secured flat against each other and by bolts laterally concealed inward of the eaves drop gutter.

Abstract: A gyroscopic azimuth aiming concept adapted to aim a drone or missile at the launch site but also to aim other military and non-military equipment. This concept is characterized by its use of a conventional rate integrating gyroscope to both measure the aiming error, which results from an approximate initial aiming done with a magnetic compass, and to effect the correction of the aiming error without the use of surveying or optical sighting instrument. This invention defines the method of measuring the aiming error including toppling the gyroscope to displace the input axis thereof from horizontal to vertical in order to provide a measure of the required angular correction. This invention also defines a device wherein a conventional rate integrating gyroscope is pivotally mounted to allow rotation of 180.degree. in azimuth between a first and a second measurements of the rotation of the input axis direction and to allow toppling of the input axis as above mentioned.