Abstract: An improved system is described for cooling high power waveguides by the use of cooling ducts extending along the waveguide, which minimizes hot spots at the flanges where waveguide sections are connected together. The cooling duct (24) extends along substantially the full length of the waveguide section, and each flange (18, 20) at the end of the section has a through hole (36) with an inner end connected to the duct and an opposite end that can be aligned with a flange hole in another waveguide section. Each flange (20) is formed with a drainage groove (60) in its face, between the through hole (36) and the waveguide conduit (16) to prevent leakage of cooling fluid into the waveguide. The ducts have narrowed sections (32, 34) immediately adjacent to the flanges to provide room for the installation of fasteners closely around the waveguide channel.

Abstract: A method and apparatus for correcting doppler shifts in synthetic aperture radar data. More particularly, in an optical correlator (10) for synthetic aperture radar data having a means for directing a laser beam (22) at a signal film (12) having radar return pulse intensity information recorded thereon, a resultant laser beam (32) then passing through a range telescope (34), an azimuth telescope (38), and a Fourier transform filter (36) located between the range and azimuth telescopes, thereby forming an image for recordation on an image film (40), a compensation means for doppler shift in the radar return pulse intensity information includes a beam splitter (46) for reflecting the modulated laser beam, after having passed through the Fourier transform filter (36), to a detection screen (48) having two photodiodes (66 and 68) mounted thereon. The photodiodes are positioned on each side of the Gaussian distribution of the Fourier transform spectrum reflected by the beam splitter (46).

Abstract: A skin friction measuring device for measuring the resistance of an aerodynamic surface to an airstream, adapted to be mounted on an aircraft, within an opening defined therein, and characterized by a friction plate adapted to be disposed in a flush relationship with the external surface of the aircraft and be displaced in response to skin-friction drag, as an airstream is caused to flow over the surface thereof, and a potentiometer connected to the plate for providing an electrical output indicative of the magnitude of the drag.