Theoretical Investigation on Effect of Helicopter Main Rotor Parameters in Required Power

The main rotor is the principal factor effecting helicopter performance and fuel consumption. There are many basic geometric parameters that constitutive the main rotor design. Radius and chord are among these basic geometric parameters. In this study, it is aimed to examine the effects of variation in radius and chord on required power at different flight conditions. Based on the design values of B0105 and S-76 from utility helicopter the group, the power calculations were made for the main rotor only when the radius and only the chord changed between +8% and -8%, and both parameters changed between +8% and 8%. These calculations were repeated for hover, 50 knots, 90 knots, 130 knots forward flights, and for sea level, 5000 ft, 10000 ft altitudes. With the variation of radius and chord, the cases that the maximum reductions and increases in required power were revealed. Results shows İncreasing the chord alone resulted in an increase in required power in all flight conditions. It has been observed that the combinations obtained by variation the radius and chord of maximum decrease and increase amount in the required power are different from according to the altitude, suspension condition and forward flight velocity.