By Tommy H. Thomason

Tuesday, July 14, 2009

The Variable-Incidence Wing

At one point during Grumman's long and ultimately futile first attempt to provide the Navy with a swept-wing jet fighter, its XF10F Jaguar sported a two-position variable-incidence wing. When this mockup was constructed, the design also featured a low(ish) horizontal tail. The final configuration was the equally radical variable-sweep wing, combined with an attempt at creating a horizontal tail control system that eliminated the need for a hydraulic actuator. Ironically, it was the latter and not the former that proved almost as troublesome as the J40 engine. Grumman did a design study substituting the J57 but by then both the Navy and Grumman wanted to move on. However, if 1) Grumman had stuck with the variable-incidence wing and what was to become the preferred location of the stabilizer in supersonic flight and 2) the J57 had become available to replace the wretched J40, the Jaguar still wouldn't have been as fast as the Crusader because the basic airframe shape was the antithesis of area rule...


Donald B Terrana said...

The wing support structure provided both the sweep angle change and forward movement of the wing to control the relationship between the center of gravity and the wing center of pressure.

This required a unique design where the wing was supported on the side of the body and fuselage center line, in such a way that wing bending was reacted only as vertical loads with no bending moments going through the wing pivot joint.

I expect add to the description the structure in more detail shortly

Aerofranz said...

Was that similar to the mechanism used on the Bell X-5? Good pictures of the X-5's sweep mechanism can be found in Jay Miller's "X-Planes".