Accession Number : ADA136912

Title :   A Wind Tunnel Investigation to Determine Dominant Forebody Strake Design Characteristics for an F-15 Equipped with Conformal Fuel Tanks.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Duncan,T A

PDF Url : ADA136912

Report Date : Dec 1983

Pagination or Media Count : 127

Abstract : A parametric study was made in the AFIT 5-ft wind tunnel of forebody strakes on an F-15C model equipped with conformal fuel tanks. Parameters of interest were strake planform area and strake angle of incidence. Twenty configurations were evaluated for longitudinal and lateral stability at angles of attack from -4 to 46 deg. Lift coefficient, drag coefficient, and pitching moment coefficient (CM) were plotted angle of attack (alpha). Data indicated that an excessive positive increase in the derivative of CM/derivative of alpha can be expected at angles of attack of 20 deg or less. Above 20 deg, CM may be tailored by varying the strake area and incidence angle. For each strake examined, and angle of incidence of either -3 or -6 deg (depending on planform area) produced a more nearly linear CM vs alpha curve than 0 degrees; therefore, incidence angle should be considered in strake design optimization. Lateral stability data were taken on 12 configurations from 16 to 44 deg angle of attack. To determine spin susceptibility, the parameter for predicting lateral-directional stability was plotted for the most promising configurations. Very little constructive change in lateral stability was noted for the configurations tested.

Descriptors :   *Strakes, Pitch(Motion), Yaw, Fuel tanks, Conformal structures, Planform, Wind tunnel tests, Aerodynamic stability, Angle of attack, Camber, Lift, Drag, Coefficients, Moments, High angles, Low angles, Angle of incidence, Vortices, External stores, Jet fighters, Wind tunnel models, Experimental data, Theses

Subject Categories : Aerodynamics
      Attack and Fighter Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE