Accession Number:

AD0879656

Title:

Engineering Flight Test, YUH-1H Helicopter, Phase D (Limited)

Descriptive Note:

Final rept. Feb 1966-Aug 1967

Corporate Author:

ARMY AVIATION SYSTEMS TEST ACTIVITY EDWARDS AFB CA

Personal Author(s):

Report Date:

1970-11-01

Pagination or Media Count:

263.0

Abstract:

This report presents the results of a limited Phase D Engineering Flight Test of the YUH-1H helicopter equipped with the Lycoming T53-L-13 engine. The objectives of the test were to define the increased performance, to evaluate the engine characteristics and to investigate the flying qualities resulting from the expanded flight envelope. One hundred and fifteen data flights were conducted from December 1966 to August 1967 accounting for 98 productive flight hours. Testing was conducted in California at Edwards Air Force Base and at auxiliary test sites at Bakersfield and Bishop. Helicopter performance was quantitatively defined for hover, takeoff, climb and level flights. Engine characteristics and helicopter flying qualities were determined quantitatively at specific flight conditions and were qualitatively investigated throughout the operating flight envelope. The performance of the UH-1D was significantly improved by the installation of the higher powered T53-L-13 engine which resulted in an increased weight, temperature and altitude flight envelope. The T53-L-13 engine demonstrated good dynamic characteristics except for instability at topping power and poor static characteristics. In general, the helicopter flying qualities were acceptable in forward flight. During low-speed flight and hover, the left directional control margin was inadequate. At a forward center of gravity, the helicopter has insufficient aft longitudinal control. To safely use the increased flight envelope, the control deficiencies must be corrected.

Subject Categories:

  • Helicopters

Distribution Statement:

APPROVED FOR PUBLIC RELEASE