Horizon projection device for aircraft simulator

Claim 1

An horizon projection device for an aircraft simulator comprising: an image forming an aerial representation of a part of the Earth's surface; optical means for projecting the image on a concave spherical surface; a scanning device for moving the projection of the image over the concave spherical surface; rotation means for rotating the projection of the image about its center; control means responsive to the heading, attitude and altitude of the aircraft simulated to the pilot for controlling the projection of the image, the dimensions of the image and the scanning device to provide the projection of the horizon with the position and the dimensions corresponding to alterations of the course of the aircraft; variable magnification optical means between the image and the wide angle lens, said variable magnification optical means being adapted to form an intermediate image in the focal plane of the wide angle lens, the dimensions of the intermediate image depending upon the magnification of said variable magnification means, said control means responsive to the altitude of the aircraft being coupled to control the magnification of the variable magnification optical means, and comprising means responsive to simulated turning of the aircraft over on its back for modifying the magnification of the variable magnification optical means, whereby when a pilot within the simulator controls the simulation of the aircraft to turn over on its back, the apparent variation of altitude is compensated; means for causing a set of patterns to move across said image at speed dependent upon the simulated speed of said aircraft with respect to ground; means for rotating the overall direction of movement of the patterns in response to the action of the pilot on the heading of the aircraft; and means for maintaining the set of patterns motionless in relation to the center of said set during a simulated change of heading, in relation to the contour of said image, the patterns, adapted to move across the image forming an aerial representation of a part of the Earth's surface, being formed by luminous or dark patches, obtained by a mixture of immiscible liquids having closely related densities, means for setting said immiscible liquids in motion, this mixture of liquids being set in motion between two transparent plates whereby the plates and the liquids flowing between the plates may rotate about an axis perpendicular to the mean plane of said plates, the means for maintaining the set of patterns motionless in rotation during a simulated change of heading comprising two fixed circular discs disposed sealingly in apertures provided in said plates, these discs being formed from a transparent material and having their center located on the rotational axis of the plates, whereby during rotation of the plates, corresponding to a change of heading, the set of patterns formed by the mixture of immiscible liquids remains motionless due to the inertia of the liquids and the adhesion of these liquids to the surfaces of the motionless discs.