The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 27, 1993
Filed:
Aug. 08, 1991
Floyd W Hagen, Eden Prairie, MN (US);
Rosemount Inc., Eden Prairie, MN (US);
Abstract
An angle of attack sensor is provided with ports for sensing flow angles in desired planes based upon differential pressure at the ports when a longitudinal or reference axis of the sensor changes relative to the flow stream. Impact pressure is also measured with the same probe, or with a separate probe, and the angle of attack is calculated by subtracting the pressures at the angle sensitive ports, and dividing by the measured impact pressure (q.sub.cm). At higher angles of attack, the denominator q.sub.cm approaches and passes through zero. When this quantity, q.sub.cm, approaches zero, the angle of attack signal becomes undefined. The problems encountered as q.sub.cm approaches zero has been a limitation of useful angle of attack range of angle of attack sensors for many years. It has been discovered that if the angle of attack ratio, where q.sub.cm is the denominator, is inverted at some point when the denominator q.sub.cm approaches zero, the useable range of indication of angle of attack can be greatly extended. The present invention provides apparatus and method for inverting the ratio at selected values of q.sub.cm.