Analysis work by Boeing engineer Vic Ganzer suggested an optimum sweepback angle of about 35 degrees.
2.
The wing planform of the F-15 suggests a modified cropped delta shape with a leading-edge sweepback angle of 45?
3.
In contrast with the German design which could only have its wing sweepback angle adjusted on the ground, the Bell engineers devised a system of electric motors to adjust the sweep in flight.