METHODS FOR OBTAINING DESIRED HELICOPTER STABILITY CHARACTERISTICS AND PROCEDURES FOR STABILITY PREDICTIONS 1

In thefirst part of thk report a brief review ti presded of methodsavailableto the helicopterdm”grwrfor obtaining desired s[ability cluzrackri.dcs by modifications to the airframe design. The discussion is based on modij.cations de dwring the establishnwnt of $ying-qualiiies criteriu and includtx sample resulk of theorettil tdudiesof additionalmethods. The conclum”onh reached tti it is m feasible to utilize combinations oj methoohwhereby etubiLdy-paxametervalua are realiwd which in turn provide the dm”red stability chwac-terkhks. Part II reuiewssome of the method8of predicting rotor 8.tu-bility derivatives. The procedur ~ by which these rotor derivu-tiuesare employed to estimatehelicopter stability chm-acttiti.cs ha.?ebeen summarized. Although be methodsare not a.i?wagm adequatefor predicti ~ absolute calues of h stubility of