Army Preliminary Evaluation. YAH-1S Helicopter with Modified Flat Plate Canopy Installed
Army Preliminary Evaluation. YAH-1S Helicopter with Modified Flat Plate Canopy Installed

Author: James R. Arnold

Publisher:

Published: 1977

Total Pages: 83

ISBN-13:

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The United States Army Aviation Engineering Flight Activity conducted an Army Preliminary Evaluation of the YAH-1S helicopter to determine the effect of the modified flat plate canopy installation on performance and combined effects of the canopy and the Kaman K-747 rotor on handling qualities. The helicopter was tested from 18 March through 15 June 1977 at Edwards Air Force Base, California. During the test, 28 flights totaling 23.8 productive flight hours were flown. The increase in equivalent flat plate area due to the modified flat plate canopy installation was approximately 3 square feet. Two deficiencies noted during this evaluation were the high intensity of mirror images of both internal and external light sources on the modified flat plate canopy during night flight and the design/location of the night vision goggle switch, which is conductive to inadvertent deactivation of the visual fault warning system. A total of nine shortcomings were noted. (Author).

Army Preliminary Evaluation YAH-IQ Helicopter with a Flat-Plate Canopy
Army Preliminary Evaluation YAH-IQ Helicopter with a Flat-Plate Canopy

Author: James R. Arnold

Publisher:

Published: 1975

Total Pages: 40

ISBN-13:

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The United States Army Aviation Engineering Flight Activity conducted a limited evaluation of the level flight performance and handling qualities of a YAH-1Q helicopter with a flat-plate canopy from 17 through 19 June 1975 at the Bell Helicopter Company flight test facility at Arlington, Texas. During the test program, eleven flights for a total of 4.4 productive hours were flown. A loss in maximum airspeed for level flight was determined when compared to the AH-1G (Bell Helicopter Company data indicate 5 to 7 knots). The primary effect of the flat-plate canopy on handling qualities was a noticeable decrease in directional stability. The one deficiency determined during the evaluation was the internal reflection from external light sources on the flat-plate canopy during night flight. Five shortcomings were noted during the evaluation. Further testing should be conducted to determine the effect of the decreased directional stability on the accuracy of rocket fire.

Army Preliminary Evaluation YOH-58A Helicopter with a Flat-Plate Canopy
Army Preliminary Evaluation YOH-58A Helicopter with a Flat-Plate Canopy

Author: James R. Arnold

Publisher:

Published: 1975

Total Pages: 44

ISBN-13:

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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).

Preliminary Airworthiness Evaluation AH - 1S (MC (Modernized Cobra)) Helicopter with External Fuel Tanks Installed
Preliminary Airworthiness Evaluation AH - 1S (MC (Modernized Cobra)) Helicopter with External Fuel Tanks Installed

Author: John I. Nagata

Publisher:

Published: 1984

Total Pages: 83

ISBN-13:

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The Preliminary Airworthiness Evaluation of the AH-1S Modernized Cobra, (S/N 69-16423) with the Kellett ferry tanks installed was conducted at Edwards Air Force Base, California (2302 feet) and Bakersfield, California (488 feet). Approximately 19 productive hours were flown during 24 flights between 17 March and 27 April 1984. The Kellett ferry tanks increased the equivalent flat plate area by 2.0 sq ft. One deficiency noted during the evaluation was the lack of crashworthiness of the external fuel tanks. Four shortcomings associated with the installation of the external fuel tanks were found.