Engineering Flight Test of the YCH-47C Medium Transport Helicopter. Army Preliminary Evaluation I.
Engineering Flight Test of the YCH-47C Medium Transport Helicopter. Army Preliminary Evaluation I.

Author: Jerry L. Jester

Publisher:

Published: 1968

Total Pages: 90

ISBN-13:

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Army Preliminary Evaluation I was conducted to verify the performance guarantees, obtain limited handbook data and evaluate the mission effectiveness of the YCH-47C helicopter. The maximum cruise speed capability was 155 KTAS and limited by heavy cockpit vibration. The outstanding 95 degree Fahrenheit day in ground effect and out of ground effect hover capability enhances the mission effectiveness of the aircraft. The flight envelope release V(NE) for all gross weights tested at 245 rpm rotor speed and low and high altitudes was not attained. The airspeed was limited by as much as 15 KTAS due to heavy cockpit vibration, but not to the extent that the mission effectiveness of the helicopter would be seriously degraded. The V(NE) was easily exceeded for all gross weights tested at 235 rpm rotor speed-high altitudes with no vibration limitations encountered.

Engineering Flight Test of the YCH-47C Medium Transport Helicopter. Army Preliminary Evaluation II.
Engineering Flight Test of the YCH-47C Medium Transport Helicopter. Army Preliminary Evaluation II.

Author: Jerry L. Jester

Publisher:

Published: 1969

Total Pages: 204

ISBN-13:

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The evaluation consisted of limited level flight performance tests and stability and control tests. Within the scope of tests all but six stability and control requirements of the detail and military specifications were met. Correction of two deficiencies is mandatory for acceptable mission capabilities. These deficiencies are the static and dynamic longitudinal stability improved helicopter capabilities. Safety of flight was affected by aft rotor blade stall characteristics in maneuvering flight and bank angles above 30 degrees and requires a reduction in maximum bank angles permitted. High aft rotor flight control component stress levels associated with maneuvering flight and operation at limit airspeeds requires that a visual flight loads display be incorporated in the cockpit.

Army Preliminary Evaluation III and IV YCH-47C Medium Transport Helicopter
Army Preliminary Evaluation III and IV YCH-47C Medium Transport Helicopter

Author: Jerry L. Jester

Publisher:

Published: 1970

Total Pages: 148

ISBN-13:

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Army Preliminary Evaluation (APE) consisted of vibration noise level tests and a re-evaluation of the stability and control characteristics modified by the incorporation of engineering changes to correct the handling qualities deficiencies found during APE II. APE IV was a re-evaluation of the vibration characteristics which was required because of structural modifications incorporated in the aircraft following APE III. The helicopter showed significant improvements in trimmability, static and dynamic longitudinal stability and lateral-directional stability as compared to aircraft flown during APE I and II. The longitudinal stability improvements permitted sustained hands off flight. The vibration levels experienced during APE IV were improved over APE III. The aircraft met all requirements except two of the detail specification and two of the military specification.

Engineering Flight Test of the YCH-47B Helicopter Army Preliminary Evaluation I, II and III.
Engineering Flight Test of the YCH-47B Helicopter Army Preliminary Evaluation I, II and III.

Author: Norman A. Mattmuller

Publisher:

Published: 1969

Total Pages: 166

ISBN-13:

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The Army Preliminary Evaluation of the YCH-47B helicopter was conducted by the US Army Aviation Systems Test Activity at Philadelphia, Pennsylvania in three phases during the period 1 March 1967 to 31 August 1967. The improvements in hover and level flight performance were defined and the change in flying qualities from those of the CH-47A helicopter were evaluated. An objectionable level of noise and vibration was encountered during testing; however, a significant reduction in vibration was achieved by the reduction of recommended rotor rpm from 230 to 225. An expansion of the 16,000 pound external load flight envelope to that of the helicopter with internal loads was substantiated with the exception of bank angle limitations. As a result of stress checks performed in turn maneuvers, the bank angle envelope was reduced to avoid excessive fatigue damage on aft rotor head control components. (Author).

Helicopter Test and Evaluation
Helicopter Test and Evaluation

Author: Alastair Cooke

Publisher: John Wiley & Sons

Published: 2009-02-12

Total Pages: 384

ISBN-13: 1405172541

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Although a number of texts on helicopter aerodynamics have been written, few have explained how the various theories concerning rotorborne flight underpin practical flight test and evaluation. This book combines theoretical information on aerodynamics, stability, control and performance with details of evaluation methodologies and practical guidance on the conduct of helicopter flight tests. For each topic the relevant theory is explained briefly and followed by details of the practical aspects of testing a conventional helicopter. These include: * safety considerations * planning the tests * the most efficient way to conduct individual flights Where possible typical test results are presented and discussed. The book draws on the authors' extensive experience in flight test and flight test training and will appeal not only to professionals working in the area of rotorcraft test and evaluation, but also to helicopter pilots, rotorcraft designers and manufacturers and final year undergraduates of aeronautical engineering

Service Test of the CH-47C Helicopter
Service Test of the CH-47C Helicopter

Author: Harold L Huff (Jr)

Publisher:

Published: 1969

Total Pages: 276

ISBN-13:

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The US Army Aviation Test Board service tested the CH-47C Helicopter to determine its suitability for Army use. The test was conducted at Fort Rucker, Alabama; Apalachicola, Florida; Fort Bragg, North Carolina; Yuma Proving Ground, Arizona (desert environment); and Fort Carson, Colorado (high elevation environment). A total of 172 flight hours was accumulated during the period. The CH-47C was compared to the CH-47A and B and to the Revised Military Characteristics for Medium Transport Helicopter. The flight characteristics, performance, operational capabilities, and maintainability of the CH-47C were enhanced over those of the CH-47A and B.