Airworthiness Qualification Evaluation U-21A Airplane with Low Reflective Paint and Hot Metal Suppressors.
Abstract
The United States Army Aviation Engineering Flight Activity conducted an airworthiness qualification evaluation of a U-21A airplane painted with acrylic lacquer low reflective (LR) olive drab paint and with infrared IR) hot metal suppressors installed. The evaluation was accomplished in three phases between 25 June and 17 September 1975 to establish a flying qualities and performance base line for the basic U-21A and then to separately determine the degradation due to the application of LR paint and the installation of the IR suppressors. During the test program 47 productive test flight hours were flown. Performance, stability and control characteristics, and miscellaneous engineering tests were conducted. During these tests no deficiencies and ten handling qualities shortcomings (not a result of the LR paint or IR suppressor installation) were noted. In general, the most significant changes resulting from the addition of LR paint were the 3-knot indicated airspeed (KIAS) increase in stall airspeed, the slight reduction in the pitot-static source position error, and a minor performance degradation. The combination of LR paint and IR suppressors resulted in an additional 3-KIAS airspeed increase in stall airspeed (total of 6 KIAS) and sufficient degradation in performance to warrant recommending the publication of an IR performance supplement to the operator's manual, using the data for the U-21A with all IR modifications as a basis and annotating it for use by all LR-painted U-21A airplanes, with and without IR suppressors installed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1976
- Accession Number
- ADA047656
Entities
People
- Raymond B. Smith
- William A. Norton