Polish Air Force Academy: Researcher Studies Aerodynamics of 3D Printed Aircraft Model

Robert Babel of the Polish Air Force Academy recently published ‘The initial analysis of the aerodynamic characteristics of a 3D printed model of an aircraft’ as he explored use of the progressive technology in aerodynamics studies, and designs. The emphasis was on studying stream-lined design and stability to create a plane model that could withstand turbulence and any other forces that might place stress on it.

While remote control was available, Babel’s goal was to 3D print a plane model that could handle wind gusts and then balance itself automatically, without the use of electronics.

“The concept of stability and balance are so closely related,” says Babel, continuing to expound on how closely ‘and inseparably linked’ both static and dynamic stability issues are too.

Stability in terms of the y-axis is referred to as longitudinal, providing tail. In relation to both the x- and z-axis, stability is lateral and directional.

Model parts printed by FDM

Using the proper characteristics to understand aircraft performance is vital, although it varies about different conditions for the aircraft whether it is taking off, landing, climbing, or moving forward at maximum speed.

 “An important factor is also the lifting force acting on the horizontal plane to ensure the balance of longitudinal moments acting on the plane,” states Babel. “This force is variable for different angles of attack, flight speed and can be adjusted by tilting the rudder. When K excellence is equal to maximum angle excellence, maximum range is achieved. Maximum perfection is achieved when the optimum angle of attack is reached.”

To continue his study in aerodynamic characteristics, Babel used FDM 3D printing to fabricate hull components, performing all testing in a closed-circuit aerodynamic tunnel with an open-circuit circular measuring space. The 3D printed model did not work very well on the first test run, it should be noted, as some of the 3D printing parameters were off, and had to be adjusted. This is a perfect example though of one of the greatest benefits of 3D printing. When an error is discovered, adjustments can be made quickly whether in design or technical settings, and a new print can be manufactured quickly and affordably—and without having to wait on a middleman.

The model’s torque, along the transverse axis was responsible for tilting it, and Babel suggests keeping momentum low for proper flight measures. The scientist also points out that the results of this study only ‘constitute a small part of the research’ that should be performed regarding creation of this type of hull.

Diagram of the tunnel; counter-clockwise air circulation

“Research on the model in an aerodynamic tunnel allowed developing characteristics that illustrate its properties,” concluded Babel. “Characteristics have been created for all combinations of slide angle (-25- 25°) and rake angle (-20-20°) for the model with and without chassis. On this basis it can be concluded that the chassis has been very well designed, despite the fact that it increases Cx and reduces Cz and slightly perfection for most of the rake angles and small angles of slip, it should be noted that these are insignificant changes, additionally for large angles of slip the influence of the chassis improves some parameters.

“The results showed that the aircraft behaved similarly in all configurations, regardless of the value of the slip angle. The characteristics are linear positive over the entire measuring range. As the angle of attack increases, the value of the aerodynamic tilting moment coefficient increases. As the angle of attack increases, the aerodynamic transverse force coefficient increases. The angle of attack shall be sharply reduced between 12 and 20°. This is a sign of instability. The angle of slip significantly influences the characteristics of the flow of the windmill model without a collision. Depending on the value of the slip angle sign, the value of the attack angle shall be significantly below zero or significantly above zero relative to the vertical axis of the coordinate system.”

Aside from the vast field of medicine, it is hard to think of another industry that has been more impacted by 3D printing than aerospace, with NASA enjoying the benefits of 3D printing for decades—although today continually impressing us with rocket components, concepts for new Mars rovers, and even colonization in space. On the smaller level, we have also followed numerous stories regarding projects where scientists, designers, engineers, and students have been involved in using 3D printing to create innovative components.

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