Optimization of Tractor Propeller/Wing Configurations

Abstract

In this paper, a rapid, approximate calculation method for optimal lift distributions of tractor propeller/wing configurations will be formulated and discussed. Some numerical studies, performed with a computer program containing the coded method, reveal that substantial performance benefits can be obtained by adapting the wing geometry and twist distribution to generate optimum lift distribution. The example calculations show that the lift distribution for minimum induced drag differs significantly from the elliptic loading.

Furthermore, the propeller angle of attack seems to have a dominant influence on the wing performance. Mounting the propeller at a negative (tilt down) angle with reference to the wing suggests a strong reduction of overall wing induced drag. Moreover, the wing efficiency is found to be strongly dependent on the spanwise propeller position. To produce realistic lift distributions the effect of profile drag is incorporated in the model.

Experimental verification of the presented theory using data from simple propeller/wing windtunnel models proves the validity of the method for preliminary design purposes.

Keywords

propeller/wing interaction induced drag wing loading optimization

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References

Kroo

Propeller/wing integration for minimum induced loss. J. Aircraft, July 1986, 23(7), 561–565.

Miranda

L. R.

Brennan

J. E.

Aerodynamic effects of wing tip mounted propellers and turbines. AIAA 86–1802, 1986, pp. 221–228.

Veldhuis

L. L. M.

Configuration and propulsion aerodynamics research on the Low Speed Aerodynamics laboratory (in Dutch). Review of project 90-LR-5-S, Internal Report LSW 93–1, Department of Aerospace Engineering, Delft University of Technology, 1993.

Miley

S. J.

Wing laminar boundary layer in the presence of a propeller slipstream. J. Aircraft, July 1988, 25(7).

Veldhuis

L. L. M.

Induced drag reduction of tractor propeller/ wing configurations using negative propeller angle of attack. Internal Report LSW 93–2, Department of Aerospace Engineering, Delft University of Technology, 1993.

Smelt

Davies

Estimation of increase in lift due to a slipstream. ARC R&M 1788, 1937.

Durand

W. F.

Aerodynamic theory, Volume IV, 1935, pp. 169–430, Divisions J-M (Springer Verlag).

Schipholt

G. J.

Voogt

van Hengst

Investigation of methods for modelling propeller-induced flow fields. AIAA-93–0874, Jan. 1993, pp. 1–12, Reno, NV.

In-plane forces and moments of installed propellers at low speeds. ESDU 89047, 1989, ISBN 0 085679 721–9 (ESDU International plc).

10.

Janssen

An evaluation of methods for the calculation of the flow around propeller at angle of attack. MSc Thesis, Department of Aerospace Engineering, Delft University of Technology, 1991.

11.

Rentema

Een eenvoudig computerprogramma voor propellerberekeningen, gebasseerd op de vortex-theorie met Prandtl's tip verlies factor; met aanpassingen voor berekeningen met invalshoek. (Dutch) 180-uurs opdracht, Department of Aerospace Engineering, Delft University of Technology, 1993.

12.

van Es

G. W.

Experimental investigation of the effect of propeller angle of attack and position on the aerodynamic characteristics of a tractor-propeller wing combination. Thesis, 1993, Department of Aerospace Engineering, Delft University of Technology, 1993.

13.

Abott

von Doenhoff

A. E.

Theory of wing sections, 1959 (Dover Publications, Inc., New York).