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.

Aerodynamics analysis of rotor’s impact on the aircraft in the tandem wing configuration

2018 ◽  
Vol 92 (3) ◽  
pp. 336-344
Author(s):  
Marcin Figat
Keyword(s):  
Stability Margin ◽  
Static Stability ◽  
Complex Model ◽  
Numerical Code ◽  
Aerodynamic Coefficients ◽  
Sideslip Angle ◽  
Content Type ◽  
Aerodynamic Analysis ◽  
Stability Derivatives ◽  
The Impact

Purpose This paper aims to present the results of aerodynamic calculation of the aircraft in tandem wing configuration called VTOL. A presented vehicle combines the capabilities of the classic aircraft and helicopters. The aircraft is equipped with two pairs of tilt-rotors mounted on the tips of the front and the rear wing. The main goal of the presented research was to find the aerodynamic impact of both pairs of tilt-rotors on aerodynamic coefficients of the aircraft. Moreover, the rotors impact on the static stability of the aircraft was investigated too. Design/methodology/approach The CFD analysis was made for the complete aircraft in the tandem wing configuration. The computation was performed for the model of aircraft which was equipped with the four sub-models of the front and rear rotors. They were modeled as the actuator discs. This method allows for computing the aerodynamic impact of rotating components on the aircraft body. All aerodynamic analysis was made by the MGAERO software. The numerical code of the software was based on the Euler flow model. The used numerical method allows for the quick computation of very complex model of aircraft with a satisfied accuracy. Findings The result obtained by computation includes the aerodynamic coefficients which described the impact of the tilt rotors on the aircraft aerodynamic. The influence of the angle of attack, sideslip angle and the change of rotor tilt angle was investigated. Evaluation of the influence was made by the stability margin analysis and the selected stability derivatives computation. Practical implications Presented results could be very useful in the computation of dynamic stability of unconventional aircraft. Moreover, results could be helpful during designing the aircraft in the tandem wing configuration. Originality/value This paper presents the aerodynamic analysis of the unconventional configuration of the aircraft which combines the tandem wing feature with the tilt-rotor advantages. The impact of disturbance generated by the front and rear rotors on the flow around the aircraft was investigated. Moreover, the impact of rotors configuration on the aircraft static stability was found too.

scholarly journals A numerical study into the longitudinal dynamic stability of the tailless aircraft

2019 ◽  
Vol 91 (3) ◽  
pp. 428-436 ◽  
Author(s):  
Agnieszka Kwiek
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Numerical Study ◽  
Aircraft Design ◽  
Content Type ◽  
Preliminary Stage ◽  
Longitudinal Dynamic ◽  
Stability Derivatives ◽  
The Impact ◽  
Tailless Aircraft

Purpose The purpose of this research is a study into a mathematical approach of a tailless aircraft dynamic stability analysis. This research is focused on investigation of influence of elevons (elevator) on stability derivatives and consequently on the aircraft longitudinal dynamic stability. The main research question is to determine whether this impact should be taken into account on the conceptual and preliminary stage of the analysis of the longitudinal dynamic stability. Design/methodology/approach Aerodynamic coefficients and longitudinal stability derivatives were computed by Panukl (panel methods). The analysis of the dynamic stability of the tailless aircraft was made by the Matlab code and SDSA package. Findings The main result of the research is a comparison of the dynamic stability of the tailless aircraft for different approaches, with and without the impact of elevator deflection on the trim drag and stability derivatives. Research limitations/implications This paper presents research that mostly should be considered on the preliminary stage of aircraft design and dynamic stability analysis. The impact of elevons deflection on the aircraft moment of inertia has been omitted. Practical implications The results of this research will be useful for the further design of small tailless unmanned aerial vehicles (UAVs). Originality/value This research reveals that in case of the analysis of small tailless UAVs, the impact of elevons deflection on stability derivatives is bigger than the impact of a Mach number. This impact should be taken into consideration, especially for a phugoid mode.

Hypersonic dynamic stability of wave riders

2017 ◽  
Vol 89 (3) ◽  
pp. 434-443
Author(s):  
Mahmood Khalid ◽  
Khalid A. Juhany
Keyword(s):  
Dynamic Stability ◽  
Design Method ◽  
Static Stability ◽  
Small Disturbance ◽  
Similarity Parameter ◽  
Content Type ◽  
Flat Surfaces ◽  
Stability Derivatives ◽  
Cone Type ◽  
Half Cone

Purpose The purpose of this paper is to obtain close form expressions for the dynamic stability of conical wave riders with flat surfaces which could be equipped with lifting surfaces on its plain flat surface. Numerical simulation would require very large meshes to resolve flows at subscale level and the experimental evaluations would be equally difficult, requiring expensive measurement facilities with challenging procedures to secure such vehicles in confined test sections to obtain satisfactory wind on and wind off oscillations. Design/methodology/approach The design method uses appropriate pressure fields using small disturbance theory, which, in turn, is perturbed using the unsteady shock expansion theory to recover suitable expressions for the dynamic stability behaviour. Findings It was observed that the dynamic stability of the standard half-cone-type wave riders with flat upper surfaces deteriorates with the axis position measured from the pointed apex reaching a minimum at around x/co = 0.666. The half-cone wave rider with flat upper surfaces is dynamically less stable than a pure cone. Research limitations/implications The method is typically less accurate when the similarity parameter M∞θ ≤ 1 = 1 or if the angle of attack is not small. Practical implications With renewed interest in hypersonic, future hypersonically would be designed as fast lifting bodies whose shapes would be close to the configurations of hypersonic wave riders, especially if they are designed to operate at upper atmosphere altitudes. Originality/value The analytic approach outlined in this paper for the evaluation of dynamic and static stability derivatives is original, drawing from the strengths of the small disturbance theory and shock expansion techniques. The method is particularly important, as there are no reported theoretical, numerical or experimental results in the literature.

Stability analysis of the experimental airplane powered by a pulsejet engine

2019 ◽  
Vol 91 (6) ◽  
pp. 843-850 ◽  
Author(s):  
Katarzyna Pobikrowska ◽  
Tomasz Goetzendorf-Grabowski
Keyword(s):  
Stability Analysis ◽  
Eigenvalue Problem ◽  
Dynamic Stability ◽  
Design Methodology ◽  
Aircraft Design ◽  
Static Stability ◽  
Computational Time ◽  
Aerodynamic Coefficients ◽  
Content Type ◽  
Practical Implications

Purpose This paper aims to present stability analysis of a small pulsejet-powered airplane. This analysis is a part of a student project dedicated to designing an airplane to test valved pulsejet engine in flight conditions. Design/methodology/approach The panel method was chosen to compute the airplane’s aerodynamic coefficients and derivatives for various geometry configurations, as it provides accurate results in a short computational time. Also, the program (PANUKL) that was used allows frequent and easy changes of the geometry. The evaluation of dynamic stability was done using another program (SDSA) equipped with means to formulate and solve eigenvalue problem for various flight speeds. Findings As a result of calculations, some geometry corrections were established, such as an increase of the vertical stabilizer’s size and a new wing position. Resulting geometry provides satisfactory dynamic and static stability characteristics for all flight speeds. This conclusion was based on criteria given by MIL-F-8785C specifications. This paper presents the results of the first and the final configuration. Practical implications The results shown in this paper are necessary for the continuation of the project. The aircraft’s structure was being designed in the same time as the calculations described in this paper proceeded. With a few modifications to make up for the changes of external geometry, the structure will be ready to be built. Originality/value The idea to design an airplane specifically to test a pulsejet in flight is a unique one. Most RC pulsejet-powered constructions that can be heard of are modified versions of already existing models. What adds more to the value of the project is that it is being developed only by students. This allows them to learn various aspects of aircraft design and construction on a soon-to-be real object.

Numerical evaluation of the exhaust-direction effects on plume flow and helicopter infrared radiation under hover and cruise statuses

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zongyao Yang ◽  
Yong Shan ◽  
Jingzhou Zhang
Keyword(s):  
Radiation Intensity ◽  
Infrared Radiation ◽  
Design Methodology ◽  
Main Rotor ◽  
Content Type ◽  
Exhaust Plume ◽  
Ir Signature ◽  
Plume Flow ◽  
The Impact ◽  
Rotational Direction

Purpose This study aims to investigate the effects of exhaust direction on exhaust plume and helicopter infrared radiation in hover and cruise status. Design/methodology/approach Four exhaust modes are concerned, and the external flow field and fuselage temperature field are calculated by numerical simulation. The infrared radiation intensity distributions of the four models in hovering and cruising states are computed by the ray-tracing method. Findings Under the hover status, the exhaust plume is deflected to flow downward after it exhausts from the nozzle exit, upon the impact of the main-rotor downwash. Besides, the exhaust plume shows a “swirling” movement following the main-rotor rotational direction. The forward-flight flow helps prevent the hot exhaust plume from a collision with the helicopter fuselage generally for the cruise status. In general, the oblique-upward exhaust mode provides moderate infrared radiation intensities in all of the viewing directions, either under the hover or the cruise status. Compared with the hover status, the infrared radiation intensity distribution alters somewhat in cruise. Originality/value Illustrating the influences of exhaust direction on plume flow and helicopter infrared radiation and the differences of helicopter infrared radiation under hover and cruise statuses are identified. Finally, an appropriate exhaust mode is proposed to provide a better IR signature distribution.

scholarly journals Conceptual design of an aircraft for Mars mission

2019 ◽  
Vol 91 (6) ◽  
pp. 886-892
Author(s):  
Agnieszka Kwiek
Keyword(s):  
Stability Analysis ◽  
Dynamic Stability ◽  
Conceptual Design ◽  
Design Stage ◽  
Content Type ◽  
Mars Mission ◽  
Longitudinal Dynamic ◽  
Short Period ◽  
The Impact ◽  
Tailless Aircraft

Purpose The purpose of this paper is to present the results of a conceptual design of Martian aircraft. This study focuses on the aerodynamic and longitudinal dynamic stability analysis. The main research questions are as follows: Does a tailless aircraft configuration can be used for Martian aircraft? How to the short period characteristic can be improved by side plates modification? Design/methodology/approach Because of a conceptual design stage of this Martian aircraft, aerodynamic characterises were computed by the Panukl package by using the potential flow model. The longitudinal dynamic stability was computed by MATLAB code, and the derivatives computed by the SDSA software were used as the input data. Different aircraft configurations have been studied, including different wing’s aerofoils and configurations of the side plate. Findings This paper presents results of aerodynamic characteristics computations and longitudinal dynamic stability analysis. This paper shows that tailless aircraft configuration has potential to be used as Martian aircraft. Moreover, the study of the impact of side plates’ configurations on the longitudinal dynamic stability is presented. This investigation reveals that the most effective method to improve the short period damping ratio is to change the height of the bottom plate. Practical implications The presented result might be useful in case of further design of the aircrafts for the Mars mission and designing the aircrafts in a tailless configuration. Social implications It is considered by the human expedition that Mars is the most probable planet to explore. This paper presents the conceptual study of aircraft which can be used to take the high-resolution pictures of the surface of Mars, which can be crucial to find the right place to establish a potential Martian base. Originality/value Most of aircrafts proposed for the Mars mission are designed in a configuration with a classic tail; this paper shows a preliminary calculation of the tailless Martian aircraft. Moreover, this paper shows the results of a dynamic stability analysis, where similar papers about aircrafts for the Mars mission do not show such outcomes, especially in the case of the tailless configuration. Moreover, this paper presents the results of the dynamic stability analysis of tailless aircraft with different configurations of the side plates.

Aerodynamic and static stability investigation into aircraft coupled system to suborbital space flights

2021 ◽  
Vol 93 (2) ◽  
pp. 275-283
Author(s):  
Marcin Figat ◽  
Agnieszka Kwiek
Keyword(s):  
Flow Model ◽  
Coupled System ◽  
Inviscid Flow ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Mutual Position ◽  
Content Type ◽  
Space Flights ◽  
Centre Of Gravity ◽  
The Impact

Purpose The aim of the research is to conduct a study into a configuration of an aircraft system with a focus on aerodynamics. In addition, trim condition and static stability constraints were included. The main application of this system is suborbital space flights. The presented concept of a modular airplane system (MAS) consists of two vehicles: a Rocket Plane and a Carrier. Both are designed in tailless configurations but coupled formed a classic tail aircraft configuration, where the Rocket Plane works as the empennage. The most important challenge is to define the mutual position of those two tailless vehicles under the assumption that each vehicle will be operating alone in different flight conditions while joined in one object create a conventional aircraft. Each vehicle configuration (separated and coupled) must fulfil static stability and trim requirements. Design/methodology/approach Aircrafts’ aerodynamic characteristics were obtained using the MGAERO software which is a commercial computing fluid dynamics tool created by AMI Aero. This software uses the Euler flow model. Results from this software were used in the static stability and trim condition analysis. Findings The main outcome of this investigation is a mutual position of the Rocket Plane and the Carrier that fulfils project requirements. Also, the final configuration of both separated vehicles (Rocket Plane and Carrier) and the complete MAS were defined. In addition, it was observed that in the case of classic aircraft configuration which is created by connecting two tailless vehicles increasing horizontal tail arm reduces static stability. This is related to a significantly higher mass ratio of the horizontal tail (the Rocket Plane) with respect to the whole system. Moving backward, the Rocket Plane has a notable effect on a position of a centre of gravity of the whole system static stability. Moreover, the impact of the mutual vehicles’ position (horizontal tail arm) and inclination angle on the coupled vehicle lift to drag ratio was analysed. Research limitations/implications In terms of aerodynamic computation, MGAERO software using an inviscid flow model, therefore, both a friction drag and breakdown of vortex are not considered. But the presented research is for the computation stage of the design, and the MGAERO software guarantees satisfactory accuracy with respect to the relatively low time of computations. The second limitation is that the presented results are for the conceptual stage of the design and dynamic stability constraints were not taken into account. Practical implications The ultimate goal of the coupled aircraft project is to conduct flying tests and the presented result is one of the milestones to achieve this goal. Originality/value A design process for a conventional aircraft configuration is well known however, there are not many examples of vehicles that consist of two coupled aircrafts where both vehicles have similar mass. The unique part of this paper includes results of the investigation of the mutual position of the vehicles that can fly alone, as well as in coupled form. The impact of the position of the centre of gravity on trim conditions and static stability of the coupled configuration was investigated.

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