THEORETICAL INVESTIGATION OF DYNAMIC STABILITY DERIVATIVES OF DUCTED PROPELLERS

1963 ◽  
Author(s):  
A. R. Kriebel ◽  
A. H. Sacks ◽  
J. N. Nielsen
Keyword(s):  
Dynamic Stability ◽  
Theoretical Investigation ◽  
Stability Derivatives ◽  
Derivatives Of ◽  
Ducted Propellers

Aerodynamics analysis of the main rotor influence on the static stability of the gyroplane

2017 ◽  
Vol 89 (5) ◽  
pp. 663-670 ◽  
Author(s):  
Marcin Figat
Keyword(s):  
Dynamic Stability ◽  
Static Stability ◽  
Main Rotor ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Flight Condition ◽  
Configuration Change ◽  
Stability Derivatives ◽  
The Impact ◽  
Derivatives Of

Purpose This paper aims to present the results of aerodynamic calculation of impact the main rotor on the fuselage and the tail of a light gyroplane. This kind of vehicle is a type of rotorcraft which uses a non-powered rotor in autorotation to develop lift and engine-powered propeller to provide the thrust. Both of them disturb the flow around the gyroplane body (gyroplane fuselage and tail) and influence on its static stability. The main goal of the presented research was to find the magnitude of this influence. To measure this effect, the main stability derivatives changes of gyroplane body were investigated. Design/methodology/approach The CFD analysis of the complete gyroplane was made. Computation was performed for the model of gyroplane which was equipped with the two sub-models of the main rotor and the engine-powered propeller. Both of them were modelled as the actuator discs. This method allows to compute the aerodynamic impact of rotating components on the gyroplane body. All aerodynamic analysis was made by the MGAERO software. The numerical code of the software bases on the Euler flow model. Next, the resulting aerodynamic coefficients were used to calculate the most important stability derivatives of the gyroplane body. Findings The result obtained by computation presents the change in the most important aerodynamic coefficients and stability derivatives of the gyroplane body caused by the impact of its main rotor. Moreover, the result includes the change of the aerodynamic coefficients and stability derivatives caused by change of the main rotor configuration (change of rotation rate and angle of incidence) and change of the flight condition (gyroplane angle of attack sideslip angle and flight speed). Practical implications Analysis of the main rotor impact will be very useful for evaluation of dynamic stability of the light gyroplane. Moreover, the results will be helpful to design the horizontal and vertical tail for the light gyroplane. Originality/value This paper presents the method of the numerical analysis of the static stability of the light gyroplane’s body. The results of analysis present the impact of disturbance generated by the rotating main rotor on the static stability of the gyroplane body. Moreover, the impact of the main rotor configuration change and the flight condition change on the static stability were investigated too. The evaluation of the gyroplane’s body static stability was made by the stability derivatives. The methodology and obtained result will be very useful for analysis of the dynamic stability of the light gyroplanes. Moreover, the results will be helpful during design the main components of the gyroplane like vertical and horizontal tail.

scholarly journals Measurement of Dynamic Stability Derivatives of Tailless Lamda-shape UAV using Forced Oscillation Method

2016 ◽  
Vol 44 (7) ◽  
pp. 552-561
Author(s):  
Kwangjin Yang ◽  
Hyoungseog Chung ◽  
Donghyun Cho ◽  
Eunhye An ◽  
Joonsoo Ko ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Forced Oscillation ◽  
Stability Derivatives ◽  
Derivatives Of ◽  
Oscillation Method

Remarks on Unsteady Newtonian Flow Theory

1976 ◽  
Vol 27 (1) ◽  
pp. 66-74 ◽  
Author(s):  
G E Mahood ◽  
W H Hui
Keyword(s):  
Dynamic Stability ◽  
Centrifugal Force ◽  
Dynamic Theory ◽  
Three Dimensional ◽  
Newtonian Flow ◽  
Stability Derivatives ◽  
Impact Theory ◽  
High Mach ◽  
Derivatives Of ◽  
Double Limit

SummaryUnsteady high Mach number flows past oscillating cones and oscillating wedges are studied according to Newtonian impact theory, with and without centrifugal force corrections. It is found that, contrary to existing theories, the centrifugal force contribution in unsteady flow is significant and not negligible; for example, it contributes one-half to the dynamic stability derivatives of an oscillating wedge and one-third to that of an oscillating cone. It is also shown that in both cases the dynamic stability derivatives calculated by Newtonian impact theory with centrifugal force correction agree exactly with those obtained by gas-dynamic theory in the double limit γ → 1 and M∞ → ∞, independently. These conclusions are expected to hold for more general three-dimensional unsteady Newtonian flow when the Newtonian shock layer is attached.

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