Four deficiencies and seven shortcomings associated with flying the AH-1F in IMC were identified. The deficiencies were: (1) the easily excited lateral gust response; (2) the unsatisfactory location of avionics controls; (3) the poor cyclic flight control system mechanical characteristics; and (4) the large change in airspeed position error in climbs. The AH-1F is unacceptable for flight in IMC. Modifications evaluated in an attempt to correct the aircraft deficiencies included use of the air data system as a pitot-static source, reduction of cyclic control friction, reduction of cyclic centering spring preloads, addition of a Gurney flap to the vertical stabilizer, removal of the 90-degree gearbox fairings, addition of a ventral fin, changes in pitch and roll stability and control augmentation system gains, addition of attitude holds in the pitch and roll axes, and changes in cockpit avionics configurations. The AH-1F is acceptable for flight in IMC when the following modifications are incorporated: attitude hold capability in the pitch and roll axes, cyclic control friction adjusted to 1.0 pounds, and cyclic centering spring preloads adjusted to 3.0 pounds. The suitability of the AH-1F for flight in IMC is enhanced with VOR navigation and VHF communication control panels installed at the copilot/gunner station. In this configuration, the test aircraft was flown in actual IMC and a user evaluation was conducted. These modifications should be incorporated prior to qualification of the AH-1F for IMC flight. (fr)
AH-1F Instrument Meteorological Conditions (IMC) Flight Evaluations
1988
118 pages
Report
Keine Angabe
Englisch
Avionics , Attack helicopters , Instrument flight , Airspeed , Augmentation , Axes , Cockpits , Communication and radio systems , Configurations , Control , Control panels , Control systems , Cycles , Deficiencies , Dynamic response , Errors , Excitation , Fins , Flaps(Control surfaces) , Flight , Friction , Gunners , Gusts , Navigation , Pilots , Position(Location) , Roll , Stability , Stations , Test and evaluation , Test vehicles , User needs , Vertical stabilizers , Very high frequency , AH-1F Aircraft
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