Abstract: For the purpose of diminishing intake vortexes at jet engines with turbo-compressors of aircrafts, in particular during test runs, an apparatus is provided, which consists of a grating disposed near the ground below and directly in front of the engine inlet, which grating comprises short, approximately vertically extending wind tunnels.

Abstract: A protective facility for suppressing jet aircraft noise which has a primarily horseshoe shape for surrounding a jet aircraft. Within the horseshoe and situated to the rear of any plane within the facility is found a metal, mesh lattice which redirects exhaust gasses from the jet aircraft engines upwards. Noise from the engines, in the form of sound waves, passes through the lattice and impinges upon the facility walls; being absorbed by these walls which are covered with a sound absorbing material. At the entrance to the facility are leaves hinged to the top legs of the horseshoe which roll on curved rails. These leaves may thus be swung inwards to substantially completely enclose a plane which has been placed within the horseshoe shaped facility. The leaves are also covered with sound absorbing material to absorb and deaden noises produced at the jet engine intakes. The facility walls, including the gates, are substantially rectangular in cross-section.