Computational modeling of interference between helicopter main and tail rotors based on nonlinear blade vortex model

Ignatkin, Yu. M.; Makeev, P. V.; Shomov, A. I.

doi:10.3103/s1068799816010074

Cited by 4 publications

(3 citation statements)

References 1 publication

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“…For example, in the papers [1,2] it is declared that at the "MAI" "Designing helicopters" department was developed a method of calculating the aerodynamic characteristics of the rotor, based on a nonlinear vortex blade model, considering the diffusion of the vortex wake. The authors declare that the model and the software package are used to solve a wide range of applied problems of helicopter rotor aerodynamics and research work is conducted in the interests of the industry organizations.…”

Section: Review Of Recent Research and Publicationsmentioning

confidence: 99%

LLFWV Method for Rapid Calculation of the Aerodynamic Characteristics of Aircraft Propellers

Kybalnyy

2023

Grundlagen Der Modernen Wissenschaftlichen Forschung

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Annotation. The need to quickly obtain the aerodynamic characteristics of propellers is a rather non-trivial task at the present time. Computational aerodynamics (CFD) methods cannot be applied to solve this problem due to the complexity of the modeling, high requirements for computing resources, and the time spent on calculations. In connection with the above, there is an urgent need to develop a methodology that could help obtain the aerodynamic characteristics of propellers in the shortest possible time, and also without the need to resort to CFD methods, which is very important when there are a large number of parametric calculations.

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Section: Review Of Recent Research and Publicationsmentioning

confidence: 99%

LLFWV Method for Rapid Calculation of the Aerodynamic Characteristics of Aircraft Propellers

Kybalnyy

2023

Grundlagen Der Modernen Wissenschaftlichen Forschung

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“…This is possible when flying with a slip, or when hovering under the wind conditions. In particular, the work by Fletcher & Brown (2010) [5], the work by Ignatkin et al (2014) [6] and the work by Arda and Yüksel (2019) [7] have been focused on the computational study of the main and tail rotor interference. These works consider flying modes with the slip for the free stream conditions out of ground effect.…”

Section: Introductionmentioning

confidence: 99%

“…Experimental studies of the aerodynamic characteristics of helicopter rotors in hover and forward flight near the ground surface in wind tunnels are associated with large material and time costs, as well as significant technical difficulties. Earlier experimental work in this area has been mainly focused on the analysis of the influence of the ground surface on the aerodynamic characteristics of the rotor, such as the work by Knight and Hefner (1941) [6] and Cheeseman and Bennett (1957) [9]. Koo and Oka (1971) [10] also present the results of the flow structure study around a rotor operating near the ground.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of the Main Rotor Wake Structures and Induced Velocity Fields at the Tail Rotor Location When Flying Near the Ground

Ignatkin

Makeev

Shomov

et al. 2021

IREASE

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The distance from the rotor's hub to the ground surface in the range of H = 6-16 m and the values of free stream (flight) velocity in the range of V = 0-15 m/s are considered. The results of the visualization for both rotor wake shapes and streamlines are obtained. The influence of the ground proximity on the rotor wake shape, including the formation of "supervortex" and "ground vortex" structures are analyzed. The induced velocity fields of the main rotor in the area of the tail rotor location for various azimuth positions relative to the main rotor axis are studied. The conclusion is made about the significant influence of the ground effect on the rotor wake structure and induced velocities field, including the area of the tail rotor location. Particularly, at slip flight with speed V = 10 m/s, when the distance to the ground surface H increases from 6 to 12 m, the value of the average induced velocity at the tail rotor plane is growing up to four times. The obtained data have allowed taking into account such effects of aerodynamic interference in the simplified mathematical model of the research flight simulator of JSC Helicopters Mil and Kamov.

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Experimental research of single - rotor helicopter unintentional yaw rotation

Ефимов

Ивчин

Чернигин

et al. 2020

Naučn. vestn. MGTU GA

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Aviation accidents related to unintentional rotation may periodically occur while flying single-rotor helicopters. On-time and correct actions may help the pilot to find the way out of this hazardous situation. But it is also important to understand the situation which contributes to the unanticipated yaw occurrence, and whether there are any factors which can stop the pilot from preventing such unintentional rotation, in order to avoid these conditions. Literature analysis shows that researchers studying this phenomenon don't have the shared vision on unanticipated yaw occurrence conditions. In regards to this fact the decision to carry out a series of wind tunnel experiments using helicopter model and propeller was taken. The main object of research was a radio-controlled model of the Blade 130 x helicopter, mounted on a platform rotating around a vertical axis, which was installed on a vertical strut. Research-laboratory aerodynamic complex belonging to the Aerodynamics, Design and Aircraft Strength Chair of Moscow State Technical University of Civil Aviation was used to generate airflow. A set of dynamic experiments was carried out to determine the conditions contributing to unanticipated yaw occurrence. The analysis of the experiments has shown that there is a range of sliding angles at a certain speed of the incoming air flow which makes the helicopter yaw balancing impossible, and if the helicopter occasionally gets into this range, it inevitably leads to the unintended rotation of the helicopter on the yaw occurrence. Helicopter yaw trim inability occurs at negative sideslip angles because of tail rotor thrust decrease due to the incoming airflow blowing which decreases the blades angles of attack and worsens helicopter airframe aerodynamic moment that coincides in direction with main rotor torque if helicopter airframe possesses directional stability. In these conditions the required tail rotor pitch is greater than the available pitch so the pilot is not able to counteract the initiated unanticipated yaw rotation of the helicopter that has begun. The possibility of helicopter unanticipated yaw rotation caused by the impact of the main rotor on the tail rotor was not experimentally confirmed. It was impossible to create the conditions of unanticipated yaw occurrence during the experiments because of the tail rotor vortex ring state.

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Computational modeling of interference between helicopter main and tail rotors based on nonlinear blade vortex model

Cited by 4 publications

References 1 publication

LLFWV Method for Rapid Calculation of the Aerodynamic Characteristics of Aircraft Propellers

LLFWV Method for Rapid Calculation of the Aerodynamic Characteristics of Aircraft Propellers

Numerical Study of the Main Rotor Wake Structures and Induced Velocity Fields at the Tail Rotor Location When Flying Near the Ground

Experimental research of single - rotor helicopter unintentional yaw rotation

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