It's all done with computers (and good old-fashioned hydraulics).
- By Joe Pappalardo
- Air & Space magazine, September 2006
(Page 2 of 2)
“In those days, [the Navy] wanted high-altitude maneuverability,” says Tom Lawrence, a NAVAIR aerodynamics expert who evaluated this capability for the Tomcat. “If you had the wing pivots closer to the fuselage, you get a very large shift in the center of pressure” when the wing changes its angle of sweep. That could lead to the kind of instability that killed Raymond Popson in the X-5.
Designers attached the Tomcat’s wings so that the pivots were located at the most outboard position possible, at 8 feet, 11 inches from the fuselage centerline. The result: When the airplane changed shape, less of the wing was actually sweeping.
Though technology improved, the wing design remained basically the same, but Grumman replaced parts of the wing assembly with composite materials better able to handle heat and stress. The airplane’s role changed from chasing fast Soviet interceptors to supporting U.S. ground forces with bombing runs, and the Tomcat began showing its age.
“Back in the 1960s there was a need to vary the airplane’s geometry,” says Captain Don Gaddis of Naval Air Systems Command, a former Tomcat pilot and current program manager for its replacement, Northrop Grumman’s F/A-18 Hornet. On the F/A-18, “we’ve learned how to optimize the wing design so that the aircraft can carry out its functions” without changing geometry.