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Designing new aircraft that are state-of-the-art and beyond always requires the development of new technologies. This paper aims to present lessons learned while designing, building and testing new UAVs in the configuration of the flying wing. The UAV contains a number of aerodynamic devices that are not obvious solutions and use the latest manufacturing technology achievements, such as 3D printing.

The design solutions were applied on an airworthy aircraft and checked during test flights. The process was first conducted on the smaller UAV, and based on the test outcomes, improvements were made and then applied on the larger version of the UAV, where they were verified.

A number of practical findings were identified. For example, the use of 3D printing technology for manufacturing integrated pressure ports, investigation of the adverse yaw effect on the flying wing configuration and the effectiveness of winglet rudders in producing yawing moment.

All designed devices were tested in practice on the flying aircraft. It allowed for improved aircraft performance and handling characteristics. Several of the technologies used improved the speed and quality of aerodynamic device design and manufacturing, which also influences the reliability of the aircraft.

The paper presents how 3D printing technology can be utilized for manufacturing of aerodynamic devices. Specially developed techniques for control surface design, which can affect adverse yaw problem and aircraft handling characteristics, were described.

Additive manufacturing technology, also commonly called as 3D printing technology, is entering rapidly into the aerospace world and seems to be its future. Many manufacturing processes are replaced by this technology because the ease of use, low costs and new possibilities to make complicated parts. However, there are only few solutions which present manufacturing of structurally critical parts.

Complete process of deriving loads, design of fitting geometry, numerical validation, manufacturing and strength testing was presented. The emphasis was made to show specific features of 3D technology in printed fittings for UAV.

The research confirms that the technology can be used for the application of fittings manufacturing. Attention needs to be paid, during the design process, to account for specific features of the 3D printing technology, which is described in details.

Without a doubt, additive manufacturing is useful for manufacturing complicated parts within limited time and with reduction cost. It was also shown that the manufactured parts can be used for highly loaded structures.

The paper shows how additive manufacturing technology can be used to produce significantly loaded parts of airplanes’ structure. Only few such examples were presented till now.

This paper aims to describe the enhancement of the numerical method for conceptual phase of electric aircraft design.

The algorithm provides a balance between lift force and weight of the aircraft, together with drag and thrust force equilibrium, while modifying design variables. Wing geometry adjustment, mass correction and performance estimation are performed in an iterative process.

Aircraft numerical model, which is most often very simplified, has a number of new improvements. This enables to make more accurate analyses and to show relationships between design parameters and aircraft performance.

The presented approach can improve design results.

The new methodology, which includes enhanced numerical models for conceptual design, has not been presented before.

Conceptual and preliminary aircraft concepts are getting mature earlier in the design process, than ever before. To achieve that advanced level of maturity, multiple multidisciplinary analyses have to be done, often with usage of numerical optimization algorithms. This calls for right tools that can handle such a demanding task. Often the toughest part of a modern design is handling an aircraft’s computational models used for different analysis. Transferring geometry and loads from one program to another, or modifying internal structure, takes time and is not productive. Authors defined the concept of a common computational model (CCM), which couples programs from different aerospace scientific disciplines. Data exchange between the software components is compatible, and multidisciplinary analysis can be automated to high degree, including numerical optimization.

The panel method was applied to aerodynamic analysis and was coupled with open-source FEM code within one computational process.

The numerical results proved the effectiveness of developed methodology.

Developed software can be used within the design process of a new aircraft.

This paper presents an original approach for advanced numerical analysis, as well as for multidisciplinary optimization of an aircraft. The presented results show possible applications.

Aircraft structure mass estimation is a very important issue in aerospace. Multiple methods of different fidelity are available, which give results with varying accuracy. Sometimes these methods are giving a high discrepancy of estimated mass compared to the real mass of the structure. The discrepancy is especially noticeable in the case of small aircraft with a composite structure. Their mass properties highly depend not only on the material but also on technology and the human factor. Moreover, methods of mass estimation for unmanned aerial vehicle (UAV) platforms are even less established and examined. The purpose of this paper is to present and discuss various methods of mass estimation.

The paper presents different procedures of mass estimation for small UAVs with a composite structure. Beginning from the simplest one, where mass is estimated basing on a single equation and finishing with a mass estimation based on finite element method model and three-dimensional computer-aided design model. The results from all methods are compared with the airworthy aircraft and conclusions are discussed.

Mass of flying aircraft was estimated with different methods and compared. It revealed levels of accuracy of the investigated methods. Moreover, the influence on structure mass of human factor, glueing and painting is underlined.

Mass of the structure is a key factor in aerospace, which influences the performance of the aircraft. Thorough knowledge about the accuracy of the mass estimation methods and possible sources of discrepancies in mass analyses provides an essential tool for designers, which can be used with confidence and allows for the development of new cutting-edge constructions.

There are very few comparisons of mass estimation methods with an actual mass of manufactured and functional airframes. Additionally, mass estimation inaccuracies based on technological issues are presented, which is seldom done.

The paper aims to apply numerical optimization to the aircraft design procedures applied in the airspace industry.

It is harder than ever to achieve competitive construction. This is why numerical optimization is becoming a standard tool during the design process. Although optimization procedures are becoming more mature, yet in the industry practice, fairly simple examples of optimization are present. The more complicated is the task to solve, the harder it is to implement automated optimization procedures. This paper presents practical examples of optimization in aerospace sciences. The methodology is discussed in the article in great detail.

Encountered problems related to the numerical optimization are presented. Different approaches to the solutions of the problems are shown, which have impact on the time of optimization computations and quality of the obtained optimum. Achieved results are discussed in detail with relation to the used settings.

Investigated different aspects of handling optimization problems, improving quality of the obtained optimum or speeding-up optimization by parallel computations can be directly applied in the industry optimization practice. Lessons learned from multidisciplinary optimization can bring industry products to higher level of performance and quality, i.e. more advanced, competitive and efficient aircraft design procedures, which could be applied in the industry practice. This can lead to the new approach of aircraft design process.

Introduction of numerical optimization methods in aircraft design process. Showing how to solve numerical optimization problems related to advanced cases of conceptual and preliminary aircraft design.

This is the second of two companion papers presenting the results of research into a contra‐rotating propeller designed to drive a super manoeuvrable micro air vehicle (MAV) and is devoted to the experimental results. The first paper presented the design process and numerical analyses.

Most of experiments were conducted in the wind tunnel. Both contra‐rotating and conventional propellers were tested. The test procedures and equipment are described first. The attention is focused on the design of an aerodynamic balance used in the experiment. Then, the measurement error is discussed, followed by presentation of the wind tunnel results. Finally, an initial flight test of the MAV equipped with contra‐rotating propeller is briefly described.

Wind tunnel experiment results fall between theoretical results presented in the first part of the paper. The application of contra‐rotating propeller allowed to develop the propulsion system with zero torque. Moreover, the efficiency achieved appeared to be a few percent greater than that for a standard conventional propulsion system. The concept was finally proved during the first test flight of the new MAV.

The propeller was designed for a fixed wing aeroplane, not for helicopter rotor. Therefore, only conditions characteristic for fixed wing aeroplane flight are tested.

The designed contra‐rotating propeller can be used in fixed wing aeroplane if torque equal to zero is required.

Original design of the balance is described for the first time, as well as test procedures applied in this experiment. Most of wind tunnel test results are also new and never published before.

This is the first of two companion papers presenting the results of research into a contra‐rotating propeller designed to drive a super manoeuvrable micro air vehicle (MAV). The purpose of this first paper is to describe the design process and numerical analyses. The second paper is devoted to the experimental results verifying the computations.

Software based on the analytical formulas derived by Theodore Theodorsen was used in the design procedure. Three‐dimensional finite‐volume simulation, performed with the use of commercial software verified the results. Finally, two‐dimensional simulation was conducted to explore the effect of the propeller‐wing interaction. The meshes applied in these analyses are described.

Propeller geometry received as a result of the design procedure is presented. The computation results for different turbulence models applied are discussed. Time dependent characteristics of contra‐rotating propeller are presented as well as conclusions regarding propeller‐wing interaction.

Propeller was designed for a fixed wing aeroplane, not for helicopter rotor. Therefore, conditions characteristic for fixed wing aeroplane flight are analysed only. Reynolds numbers below 50000 are considered.

Designed contra‐rotating propeller can be used in fixed wing aeroplane if torque equal to zero is required. Software based on the formulas derived by T. Theodorsen can be used to design the propellers.

Software applied in the design procedure was originally developed by one of authors although it is based on the formulas derived by T. Theodorsen. Contra‐rotating propeller simulation results for different turbulence models are discussed for the first time. Moreover, unique time dependent characteristics of contra‐rotating propeller are presented.

The purpose of this paper is to make an analytical comparison of two vertical tail models from a structural point of view.

The original vertical tail design of PZL-106BT aircraft was used for Computer aided design (CAD) modeling and for creating the finite element model.

The nodal displacements, Von-Mises stresses and Buckling factors for two vertical tail models have been found using the finite element method. The idea of a possible Multidisciplinary concept assessment and design (MDCAD) concept was presented.

The used software analogy introduces an idea of having an automated calculation procedure within the framework of MDCAD.

The aircraft used for calculation had undergone a modification in its vertical tail length, as there was an urgent need to calculate for the plane’s manufacturer, PZL Warszawa – Okecie.