Design of the UAV aerodynamics in multiple stages

Ovaj rad prezentuje metodologiju aerodinamičke optimizacije bespilotne letelice sa VTOL sposobnostima. Letelice kao što su ove obično lete pri malim brzinama, i zbog toga se očekuju mali Rejnoldsovi brojevi. Otpor trenja značajno zavisi od kvaliteta proizvodnog procesa. Prema tome, ukoliko se adekvatni koraci ne preduzmu, javiće se visoki koeficijenti trenja koji mogu drastično da promene performanse letelice. Promene geometrijskih parametara ne utiču samo na indukovani otpor krila, zbog osetljivosti na promene Rejnoldsovog broja utiču i na raspodelu profilnog otpora. Napisan je kod za proračun aerodinamičkih karakteristika krila zarad određivanja optimalnih geometrijskih parametara. Svi neophodni koeficijenti su izračunati korišćenjem Galuertovog rešenja Prantlove jednačine primenjenim na višesegmentna krila. Implementacijom aerodinamičkih koeficijenata brojnih eksperimentalno ispitanih aeroprofila optimizovanim za male Rejnoldsove brojeve, raspodela profilnog otpora, i indukovani otpor krila za veliki broj napadnih uglova su izračunati. Dobijeni rezultati su predstavljeni dijagramima, a metodologija za izbor najefikasnijeg krila je opisana. Dizajn T-oblika repnih površina je izvršen analitičkom metodom, dok su metoda vrtložne mreže, DATCOM, i CFD korišćeni za potrebe verifikacije rezultata.This paper presents a methodology for aerodynamic optimization of UAV with VTOL capabilities. Aircrafts such as these usually fly at low speeds and due to that low Reynolds numbers are to be expected. The friction drag is highly dependent on the quality of the production process so unless special measures are undertaken, high friction drag coefficients could drastically influence overall performance of the aircraft. Changes of the geometrical parameters influence not only the induced drag of the wing, but also the distribution of the base drag due to sensitivity to changes of the Reynolds numbers. In order to determine the optimal geometrical parameters of the wing, a code for wing performance analysis was written. All necessary factors were calculated by utilizing the Glauert's solution of the Prandtl's equation for multi-segmented wings. By including experimental data of numerous airfoils optimized for low Reynolds numbers, the base drag distribution, along with the induced drag of the wings were calculated for a wide range of angles-of-attack. The obtained results are presented through diagrams and the methodology for the selection of the highest efficiency wing is described. The design of the T - shaped stabilizer was achieved by utilizing analytical methods while the Vortex Lattice Method, DATCOM and CFD were used for verification purposes