Army Preliminary Evaluation YOH-58A Helicopter with a Flat-Plate Canopy.
ARMY AVIATION ENGINEERING FLIGHT ACTIVITY EDWARDS AFB CALIF
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A limited evaluation of the performance and handling qualities of the OH-58A helicopter was conducted to determine the effects of a four-plane flat-plate canopy installation. Testing was conducted at the Bell Helicopter Company flight test facility at Arlington, Texas, from 25 October through 4 November 1975. Personnel from the United States Army Aviation Engineering Flight Activity conducted 11 test flights for a total of 6.5 productive test flight hours. The evaluation revealed a loss in airspeed of 2 and 6 knots at the airspeed for maximum continuous power and a loss in range of 8 and 23 nautical miles at the cruise airspeed forward and aft center-of-gravity configurations, respectively. The noticeable changes in the handling qualities were a slight increase in the nose-down pitching rate following a sudden loss of power more pronounced for the forward center-of-gravity configuration and a slight increase in the dihedral effect of the helicopter. The flat-plate canopy installation resulted in a slight reduction in the field of view, but visibility was improved due to the optical clarity of the flat-plate. The installation of glare shields between the chin bubble and canopy significantly reduced the canopy reflections during both day and night tests. One shortcoming was noted during this evaluation but cannot be attributed to the flat-plate canopy installation. Author