Handling Qualities of Helicopters and VTOL Aircraft

Reeder, J. P.

doi:10.4050/jahs.3.4

Cited by 3 publications

(4 citation statements)

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“…In Ref. 36, Jack Reeder (the chief author of MIL-H-8501) reinforces the importance of good handling for instilling a pilot's "confidence in his aircraft and himself." Reeder goes on to say that he doesn't "believe that any present production helicopter meets all of the stipulated requirements of H-8501."…”

Section: Historical Context Of Rotorcraft Handling Qualitiesmentioning

confidence: 99%

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Rotorcraft Handling Qualities Engineering: Managing the Tension between Safety and Performance 32nd Alexander A. Nikolsky Honorary Lecture

Padfield¹

2013

j am helicopter soc

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In this Nikolsky paper, I look back nearly 70 years and highlight particular events that reflect the continual growth of the handling qualities discipline. This growth has brought us to a point where designers have, within their grasp, the performance standards, the criteria and test techniques, the understanding of rotorcraft aeromechanics and control, and the design tools, to ensure that handling deficiencies never again have to define the boundary of the operational flight envelope. This point is considered very important in the evolution of the discipline and the associated flight control technologies. The pilot is a vital component in the rotorcraft system; a nearly perfectly functioning component normally, but one that can be stressed, fatigued, or overloaded, particularly when dealing with the consequences of handing qualities deficiencies, and when managing high tension between flight performance and safety. It is argued that this tension is more manageable when an aircraft has good handling qualities, throughout all missions, including flight in degraded environments and hazardous operations. This paper tells the story of how our industry has arrived at this point, how the standards and the enabling technologies have developed, spurred by user needs, and enabled by research. The paper also looks forward, highlighting how we need to strive for super-Level 1 handling qualities, a state where pilot errors, in any shape or form attributable to deficient flight characteristics, are things of the past.

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Section: Historical Context Of Rotorcraft Handling Qualitiesmentioning

confidence: 99%

“…36, but also during the decades since. I consider that challenging standards, aimed at improving both performance and safety, positively encourage innovation, rather than "hinder the development of the machine."…”

Section: Historical Context Of Rotorcraft Handling Qualitiesmentioning

confidence: 99%

Rotorcraft Handling Qualities Engineering: Managing the Tension between Safety and Performance 32nd Alexander A. Nikolsky Honorary Lecture

Padfield¹

2013

j am helicopter soc

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“…Such low-order models are valuable, but their ability to capture the complex flow physics of the VRS is limited. Flight testing to evaluate VRS has been reported by Reeder and Gustafson, 3 Brotherhood, 4 Stewart, 5 Gessow, 11 and Taghizad et al 17 among others. Experimental research on model rotors has followed a number of strands.…”

Section: Introductionmentioning

confidence: 99%

“…VRS phenomena have been observed since the early days of propeller powered flight, 2 and issues associated with the descent of a rotor toward its own wake have been reported since the early days of rotary winged flight. From a performance perspective, large thrust oscillations, an increase in average power required, and loss of control efficiency characterize the entry into the VRS regime, which can lead to loss of the aircraft, 3,4 with in-flight tests 5 and experiments 6 in the 1950s providing some insight. The VRS was identified as a flight regime to avoid, and piloting strategies evolved, but United States and United Kingdom authorities ascribed the loss of 32 helicopters to VRS between 1982 and 1997.…”

Section: Introductionmentioning

confidence: 99%

The vortex ring state of a rotor and its comparison with the collapse of an annular jet in counterflow

2023

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The vortex ring state (VRS) of a rotor is associated with the development of the trailed vortex system in powered descending flight, where the topology of the vortex wake changes from its usual helical form into a toroidal form. In the VRS the toroidal vortex ring envelops the entire rotor, and it sheds and reforms in an unsteady manner. In previous attempts to understand the basic phenomenology of the VRS, the focus was on the role of the trailed vortices in the transition to the VRS: computational and experimental work utilised rotor models to generate the trailing vortex wake, and mechanisms for the emergence of the VRS were postulated based upon the interaction of the trailed vortices. In this paper a different approach is taken: a set of experiments on a core annular jet flow are described, where the jet flow in counterflow is used to simulate a rotor in powered descent. It is shown that this leads to the formation of a flow field that shares many of the features of the VRS of a rotor system. This brings into question the role of the rotor blade trailing vortices in the development of the rotor wake VRS, and it is proposed instead that the interaction between the mean flow and counterflow drives the VRS phenomenon.

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2018

Helicopter Flight Dynamics

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Handling Qualities of Helicopters and VTOL Aircraft

Cited by 3 publications

References 0 publications

Rotorcraft Handling Qualities Engineering: Managing the Tension between Safety and Performance 32nd Alexander A. Nikolsky Honorary Lecture

Rotorcraft Handling Qualities Engineering: Managing the Tension between Safety and Performance 32nd Alexander A. Nikolsky Honorary Lecture

The vortex ring state of a rotor and its comparison with the collapse of an annular jet in counterflow

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