EXPERIMENTAL INVESTIGATION OF THE EFFECT OF VERTICAL-TAIL SIZE AND LENGTH AND OF FUSELAGE SHAPE AND LENGTH ON THE STATIC IKrERAL STABILITY CHARACTERISTICS OF A MODEL WITH 45 ° SWEFTBACK WING AND TAIL SURFACES 1-

An. investigation was made to determine the effects of certical-tail size and length and of fuselage shape and length on the static la%ral stability characteristics of a model u<th wing and vertical tails having the quatrter-cbrd lines swept back @o. 5 % results indicate that the direc&al instability of ” the ZJW%USisolated fwelages was about two-thirds aa large as that predicted by clawical-theory. A rediLcti.an in arm of wiical tails ~eometric aspect ratio kept ccmstant) attached to a giwm juiehge resulted in an increase in the eyectiue mpect ratio of the vertical tail for the range of tail sizes considered. Simple analytical considerations indicate, h.ouwer, that for tail sizes bekno the range investigated the oppo~”teefect wadd be eqwted. For the fuselqe-tail combinations imestigated, the tail e$ectiuenew usually decreased with increasing angle of artack, with the greate.d rate of decrease occum”ng at angles of attack greater than about 16°. The wing+mlage inteq(erence for & midu< ~ arrangements investigated wag only slightly afiected by the dupe of the fuselage and tended to increase slightly tha directional stability of the combination. The interference e.fects of the & @ tended to dewease the vertical-tail effectknwwj particular~y at high a.ngle~ of attack. me large efferts obsemed u~ere attributed to a par-tially staibd condition of the wing, INTRODUCTIOhr Reoent advances in the understanding of the principles of high-speed flight have kd to signitloardchangea in the design of, the principal components of airpkm=. Two of the more important changes ha~e been the incorporation of large amounts of sweep of the wing and tail surfaoes and the ele-vation of the horizontal tail to a higher positiom Muoh information is avadable on the influence of ti