Airworthiness and Flight Characteristics Test. Part 1. YAH-64 Advanced Attack Helicopter
Abstract
The Airworthiness and Flight Characteristics Test Part 1 of the prototype YAH-64 helicopter (S/N 77-23258) was conducted at three test sites; Palomar Airport, Carlsbad, California (elevation 328 ft). Bishop Airport, Bishop, California (elevation 4120 ft), and Coyote Flats, California (elevation 9980 ft). Approximately 32 productive hours were flown during 45 flights between 30 May and 17 July 1981. Several design changes affecting performance and handling qualities were made to the YAH-64 since the last evaluation (EDT 4) the most significant of which were the changes in tail rotor rigging, the addition of a third DC electrical bus and the incorporation of a Nap-of-the-Earth/ Approach mode of operation for the horizontal stabilator. Level flight performances and vibration levels have been slightly degraded since EDT 4, while handling qualities and out-of-ground-effect hover performance remain essentially the same. Numerous anomalies in the operation of the Digital Automatic Stabilization Equipment (DASE) were experienced which may render some of the handling qualities test results suspect. Two deficiencies (both DASE related) were found during this evaluation. Yaw SAS hardovers, and disengagement of the DASE with failure of the No.2 generator. Nine previously unreported shortcomings (4 DASE related) were found.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1981
- Accession Number
- ADA118490
Entities
People
- Bartholomew D. Picasso Iii
- Gary L. Bender
- John D. Ottomeyer
- Larry B. Higgins
- Richard Savage