Navy to Develop Test Techniques for New Flying Qualities

November 8, 1971November 22, 2019 admin flight test Flight Test News, FTN, November 1971, SFTE

This article first appeared in the November 1971 Flight Test News.

Advancements during the past decade in aircraft flying qualities have resulted in the adoption of a revised flying qualities specification for piloted airplanes, MIL-F-8785B. This revised specification was drafted by Cornell Aeronautical Laboratories under contract of the Air Force and approved as a military specification in 1969. This new specification has many changes in parametric requirements that are believed to be important governing variables in the field of flying qualities. These changes reflect a leaning toward direct specification of stability derivatives and mode ratios instead of flight related parameters. Although the direct specification of stability derivatives is an advancement in the guidelines for the design of future aircraft, it poses a problem for the test community in that existing flight test methods will not yield sufficient information to determine these new parametric characteristics.

The Flight Research and Development Section of the Flying Qualities and Performance Branch of the Flight Test Division at NATC has been directed to pursue a program designed to define those requirements of MIL-F-8785B for which the present flight test techniques are inadequate and to establish new techniques and data reduction procedures where possible. Presently defined problem areas are those associated with aircraft in which coupling occurs between the flight control system dynamics and the basic airplane response. Emphasis will be given to flight test methods and data reduction procedures pertaining to in-flight frequency response techniques and analog matching of airplane motions.

The benefits received from a program of this type will be reflected in the increased ability of the military test community to insure high quality in future aircraft.

Contributed by Robert Traskos, NATC Patuxent River

This article first appeared in the November 1971 Flight Test News.