Aleksander Olejnik, Piotr Zalewski, Łukasz Kiszkowiak, Robert Rogólski, Adam Dziubiński, Michał Frant, Maciej Majcher and Łukasz Omen
The purpose of this study was to analyze the possibility of using combat aircraft including decommissioned as a platform for launching and carrying space rockets with satellites…
Abstract
Purpose
The purpose of this study was to analyze the possibility of using combat aircraft including decommissioned as a platform for launching and carrying space rockets with satellites (nano and microsatellites). Thus, an airborne-launcher-to-space-system may be attractive to countries without ground-based space rocket launch sites.
Design/methodology/approach
For considered launch-to-orbit system configurations, simulations of space rocket effects on aerodynamic characteristics were performed using computational fluid dynamics (CFD ANSYS Fluent) methods. In addition, experimental studies were performed in a wind tunnel to verify the numerical simulations. Discrete models of the aircraft structure were developed for analysis using finite element method (FEM). The analysis of simulated structural properties of the models was carried out to test its stiffness and mass characteristics important for solving the static and dynamic problems of the structure. The validation analyses of aircraft models were based on mass distribution estimation and matching the stiffness properties of the individual airframe structural assemblies.
Findings
The results of numerical analyses and tunnel tests indicate that the influence of carrier rockets on the change of aerodynamic and strength characteristics of the airframe is rather negligible. The aircraft can be used as launching platforms for space rockets. Simulations have indicated that the aircraft will successfully perform a mission of taking away and launching a rocket of at least about 1,000 kg total weight with a 10 kg space payload included.
Practical implications
The combat aircraft can be used as launch platforms for space rockets, and the air/rocket set can become the equivalent of responsive space assets for countries with small space budgets.
Originality/value
The work presents original results obtained by the authors during a preliminary design of a low-cost satellite launch system consisting of a carrier aircraft and a space rocket orbiter. The possibility of using decommissioned combat aircraft as air-launch-to-orbit platforms was taken into consideration. In the absence of aircraft design documentation, reverse engineering methods and techniques were used to develop aircraft geometry and airframe strength structure. Use of CFD, FEM and simulation methods to evaluate system capabilities was demonstrated. Numerical results from CFD simulations were finally verified in experimental tests.
Details
Keywords
Andrzej Krzysiak, Robert Placek, Aleksander Olejnik and Łukasz Kiszkowiak
The main purpose of this study was to determine the basic aerodynamic characteristics of the airliner Tu-154M at the wide range of the overcritical angles of attack and sideslip…
Abstract
Purpose
The main purpose of this study was to determine the basic aerodynamic characteristics of the airliner Tu-154M at the wide range of the overcritical angles of attack and sideslip angles, i.e. α = −900° ÷ 900° and β = −900° ÷ 900°.
Design/methodology/approach
Wind tunnel tests of the Tu-154M aircraft model at the scale 1:20 were performed in a low-speed wind tunnel T-3 by using a six-component internal aerodynamic balance. Several model configurations were also investigated.
Findings
The results of the presented studies showed that at the wide range of the overcritical angles of attack and sideslip angles, i.e. α = −900° ÷ 900° and β = −900° ÷ 900°, the Tu-154M aircraft flap deflection affected the values of the drag and lift coefficients and generally had no major effect on the values of the side force and pitching moment coefficients.
Research limitations/implications
The model vibration which was the result of flow separation at high angles of attack was the wind tunnel test limitation.
Practical implications
Studies of the airliner aerodynamic characteristics at the wide range of the overcritical angles of attack and sideslip angles allow assessment of the aircraft aerodynamic properties during possible unexpected situations when the passenger aircraft is found to have gone beyond the conventional flight envelope.
Social implications
There are no social implications of this study to report.
Originality/value
The presented wind tunnel test results of the airliner aerodynamic characteristics at overcritical angles of attack and sideslip angles is an original contribution to the existing not-too-extensive database available in the literature.
Details
Keywords
Aleksander Olejnik, Adam Dziubiński and Łukasz Kiszkowiak
The purpose of this paper is to simulate with in-depth reconstruction of existing geometry a process of cooling of the aircraft engine in pusher configuration, which is more…
Abstract
Purpose
The purpose of this paper is to simulate with in-depth reconstruction of existing geometry a process of cooling of the aircraft engine in pusher configuration, which is more problematic than usually used, tractor configuration. Moreover, a complex thermal and fluid flow analysis is necessary to verify that an adequate cooling is ensured and that temperatures in the engine nacelle are maintained within the operating limits.
Design/methodology/approach
Methodology used in this research is based on computational fluid dynamics tools to model adequately the internal and the external flow, to find the state of cooling system and research the results of baffles modification inside the engine cover. Additionally, two types of the cover with different sizes of inlets and outlets are tested.
Findings
The results showed the influence of baffles modifications and changes in inlets and outlet sizes on the mass flow rate and temperature distributions inside the engine nacelle. The best configuration of air inlets and outlets was determined.
Practical implications
The method used in the research is the safest method in testing of such cases, provided the proper approach in modeling is taken. The collaboration of internal and external flow is crucial and should not be replaced with assumed flow rate through inlet and outlet area. The obtained results will help in future studies on cooling systems of engines in pusher configuration.
Originality/value
The work presents original results obtained by the authors during a complex fluid flow and heat transmission analysis and is a part of the design project of the OSA patrol aircraft.
Details
Keywords
Zdobyslaw Jan Goraj, Mariusz Kowalski, Łukasz Kiszkowiak and Aleksander Olejnik
The purpose of this paper is to present the result of simulations that were performed to assess the uncontrolled motion of the passenger aircraft following its wing tip was…
Abstract
Purpose
The purpose of this paper is to present the result of simulations that were performed to assess the uncontrolled motion of the passenger aircraft following its wing tip was suddenly cut. Such a simulation can help to understand the tendencies of aircraft behaviour after wing tip cut, assess how fast this phenomenon is going on and estimate the values of angles of attack, sideslip and pitch angle basing on given aerodynamic characteristics. Also, answer the question if pilot can counteract high deviations from flight path initially planned during the final phase of approach to landing.
Design/methodology/approach
Simulation is based on the full non-linear equations of motion derived from generalised equations of change of momentum and moment of momentum of rigid body. Dynamic equations of motion in the so-called normal mode are solved in the so-called stability frame of reference.
Findings
It was found that asymmetric rolling moment must be compensated by essential increase of pitching moment. Moreover, it appeared that aircraft goes into high angles of attack and high pitch angle and, therefore, for reliable simulation, the available aerodynamic characteristics must include angles of attack till 90 degrees when total flow separation occurs.
Practical implications
For accurate simulation, it is strongly recommended to perform to perform first the wind tunnel testing in the range of +20o ÷ 120o and use it in flight simulation.
Originality/value
The presented methodology is an original for numerical simulation of flight trajectory during the final phase of approach to landing in a hazardous state of flight. For reliable simulation, the available aerodynamic characteristics must include angles of attack till 90 degrees when total flow separation occurs, whereas usually maximum angles of attack used in wind tunnel experiments for passenger aircraft are not higher than 25 degrees. The influence of limited range of experimental data on results of simulation is another value which can be adopted in the future investigations of hazardous states of flight.
Details
Keywords
Aleksander Olejnik, Adam Dziubiński and Łukasz Kiszkowiak
This study aims to create 6-degree of freedom (SDOF) for computational fluid dynamics (CFD) simulations of body movement, and to validate using the experimental data for empty…
Abstract
Purpose
This study aims to create 6-degree of freedom (SDOF) for computational fluid dynamics (CFD) simulations of body movement, and to validate using the experimental data for empty tank separation from I-22 Iryda jet trainer. The procedure has an ability to be modified or extended, to simulate, for example, a sequential release from the joints.
Design/methodology/approach
A set of CFD simulations are calculated. Both the SDOF procedure and the CFD simulation settings are validated using the wind tunnel data available for the aircraft.
Findings
The simulation using designed procedure gives predictable results, but offers availability to be modified to represent external forces, i.e. from body interaction or control system without necessity to model the control surfaces.
Practical implications
The procedure could be used to model the separation of external stores and design the deployment of anti-radar chaff, flares or ejection seats.
Originality/value
The work presents original work, caused by insufficient abilities of original SDOF procedure in ANSYS code. Additional value is the ability of the procedure to be easily modified.
Details
Keywords
Georges Bridel, Zdobyslaw Jan Goraj, Łukasz Kiszkowiak, Jean-Georges Brévot, Jean Pierre Devaux, Cezary Szczepański and Petr Vrchota
The purpose of this paper is to reduce the exploitation cost below the standard supersonic training aircraft. The idea will benefit from the latest aerodynamic software and modern…
Abstract
Purpose
The purpose of this paper is to reduce the exploitation cost below the standard supersonic training aircraft. The idea will benefit from the latest aerodynamic software and modern avionics, allowing to use much lighter trainer (due to using composite materials and minimizing on board avionic systems), and hence, decreasing the fuel consumption and cost of operation. The need to reform advanced jet training also covers the “red air” missions (manned targets for exercise and training). Red air missions need dedicated more realistic and less costly platforms. However, this makes sense only if the performance of these platforms is comparable to a front-line combat aircraft, particularly in terms of high specific excess power (SEP) and high levels of agility. Failure to address this issue would lead to unrealistic training scenarios and a negative training experience.
Design/methodology/approach
The paper focuses on required research and the feasibility studies of a low-cost operationally effective solution for air combat pilot training, combining a very agile air platform, fully dedicated to training, and a flexible, interoperable, integrated training system (ITS) using simulations to provide a complete Live Virtual Constructive (LVC) solution. This study will explore innovations applicable to the learning and maintaining of skills, develop a first pilot physiological survey and propose a follow-up program aimed at developing a fully European air combat training service by 2028 or beyond.
Findings
The volume inside the SEP envelope shows the available SEP potential depending on Mach number and Altitude: SEP is directly representative for climb rate and acceleration or a combination of both. The surface of the volume represents steady-state conditions, i.e. at 1 g (no turns), enabling us to conclude that supersonic trainer and fighter present high energy potentials (SEP) required in air combat manoeuvres and that a subsonic trainer cannot match those qualities and does not fulfil advanced trainer requirements.
Practical implications
A major difficulty for the air forces in their training syllabus lies in the fact that in peacetime supersonic flight is restricted to dedicated areas or over the sea. However, a real beyond visual range fight can often start in the supersonic and continue into the high subsonic regime after a few minutes. Therefore, this novel trainer superior performance in the transonic region will bring the following advantages, for example in the rare opportunities to train in the lower supersonic regime, it can provide similar performance like combat aircraft and in the usual advanced training in the high subsonic regime, this novel trainer offers excellent realistic performance in a region where the conventional advanced trainer performance collapses beyond Mach 0.8 and does not provide realistic training results. The feasibility study shall be executed in close cooperation between User (Requirements) and Study Team (Solutions). The early conceptual design with basic layout and data (T/W and W/L) is key for operational utility and must be addressed with the User right at the beginning. The users are therefore offered early participation in the requirements development.
Originality/value
The presented methodology is an original approach to the combat pilot training. The core of the methodology is a study of a solution that aims to reduce training costs through an affordable operational air vehicle and an agile ITS. This goal will be reached by a design methodology that will concentrate the innovation and the developments to the critical issues for the concept (aerodynamics, propulsion, simulated weapon system, ITS architecture, etc.): the remaining topics will be adapted from existing solution, optimizing the development.