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Aerodynamic interference between pusher propeller slipstream and an airframe : literature review

Ruchała P.

Journal of KONES

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2017

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Vol. 24, No. 3

237--244

EN

In the article, an aerodynamic interference between pusher propeller slipstream and the airframe of the aircraft powered by it has been presented, based on a literature study. A pusher propeller is one of popular types of the airplane propulsion. It is applied mainly in light sport aircrafts, in the UAVs (Unmanned Aerial Vehicles), unorthodox vehicles, like compound helicopters, canard and joined wing aircrafts etc. The main advantage of pusher propeller is that the engine with the pusher propeller does not affect the visibility from the cockpit and allows placing an electronic equipment in the front part of the UAV’s fuselage. Furthermore, reduced cabin noise and increase in stability due to acting normal force aft of the centre of gravity are other benefits of this configuration. The pusher propeller impact on the airframe, especially on the wing, is qualitatively different from the tractor configuration. Main differences between both propulsions has been discussed, as well as aerodynamic benefits of the pusher propeller – like reduction of separated flow area and extending area of laminar boundary layer. However, an application of pusher propeller may have also negative impact, especially lower performance than tractor propeller. In the article the reasons of this suppression has been briefly discussed.

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Wind tunnel tests of the pusher propeller : an assessment of accuracy

Ruchała P.

Journal of KONES

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2016

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Vol. 23, No. 2

309--315

EN

A pusher propeller is one of popular types of the airplane propulsion. It is applied especially in light sport aircrafts and in the UAVs (Unmanned Aerial Vehicles). Its main advantage is that the engine with the pusher propeller does not affect the visibility from the cockpit and allows placing an electronic equipment in the front part of the UAV’s fuselage. The main disadvantage of the pusher propeller is that its performance may be worse than the tractor propeller, because of a stream distortion caused by the fuselage. It should be taken into account during propeller tests. The most accurate way is to investigate the pusher propeller in the presence of the complete airplane, as a part of airplane wind tunnel tests. However, this approach is possible in a late stage of the airplane design, when the geometry of the airplane is fixed. In the paper, an alternative, innovative approach for the propulsion tests has been presented. The propeller was investigated in a wind tunnel in a presence of the aft part of the fuselage, including a root part of the wing. A typical propeller and a ducted fan have been investigated. The results has been compared with the results of the wind tunnel tests of the complete airplane (with powered propulsion) to evaluate the accuracy of this methodology. The investigated propulsion was designed for a joined wing UAV, ILX-32 MOSUPS.

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An influence of pusher propeller cover on its performance : a concept of wind tunnel investigation

Ruchała P.

Journal of KONES

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2016

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Vol. 23, No. 4

429--434

EN

The paper describes a concept of wind tunnel investigation of the influence of the pusher propeller cover on its performance. The pusher propeller is one of the most popular types of the airplane propulsion, especially in light sport aircrafts and in the UAVs (Unmanned Aerial Vehicles). Its main advantages is that the engine with the pusher propeller does not affect the visibility from the cockpit and allows for placing an electronic equipment (for example, a camera) in the front part of the UAV’s fuselage. One of main disadvantages of pusher propeller is that it is partially covered by the fuselage and the wings of the airplane, thus the slipstream is distorted. This distortion may reduce the propeller thrust and efficiency. It may also cause vibrations of the propeller blades. This fact is well known, however it is difficult to find any quantitative information about reduction of the propeller performance. Taking it into account, it is worth to treat this subject and show a way to enhance the propeller performance. The wind tunnel tests, which concept has been described in the paper, will include measurements of total aerodynamic loads acting on the investigated object and on the propeller. Measurement of velocity distribution in the slipstream (by pressure measurement and by laser anemometry) will be included as well.