Lifting Body Stability and Control
A lifting body is a wingless vehicle that depends on lift generated from an elongated body or fuselage. Both lifting bodies and ballistic shapes had been studied as space vehicles by NASA before the choice of the Mercury, Gemini, and Apollo ballistic capsule designs. However, lifting body research continued, first at the NASA Ames and Langley Research Centers, then at the NASA Flight Research Center (Reed, 1997). Figure 14.19 is a general arrangement drawing of a typical lifting body design, the NASA/Northrop HL-10 (Heffley and Jewell, 1972). Configurations such as the HL-10 have evolved into the space shuttle Orbiter and follow-up concepts such as the X-33 research vehicle.
Figure 14.19 Three-view drawing of the NASA/Northrop HL-10 lifting body. (From Heffley and Jewell, NASA CR-2144, 1972)
Stability and control characteristics of a series of lifting bodies were investigated in wind – tunnel and flight tests starting in the mid-1950s in the United States and later in Russia, Japan, and France. All of the problems associated with swept wings and heavy fuselage loadings appeared in the course of these tests, in addition to a number of instances of control oversensitivity and pilot-induced oscillations. Lifting body configurations typically have high dihedral effect, or rolling moment due to sideslip, in proportion to roll damping. The coupled roll-spiral mode of motion (Chapter 18, Sec. 9) may thus exist.