During the Kennedy/Johnson/McNamara conventional buildup,it was clear that because of costs and manpower America could not match the Sovietsí vastly greater numbers of conventional weapons, so American conventional weapons doctrine focused on ìforce multipliersî provided by fewer but more sophisticated and effective conventional weapons that could kill at a 3-4:1 ratio.
Sprey and Boyd disagreed with this doctrine and the high-tech systems it required. The two began to work on an alternate concept to the "Blue Bird,"called the "Red Bird" a clear weather, air-to-air combat only fighter with a top speed of Mach 1.6 instead of the Blue Bird's Mach 2.5+. Boyd and Sprey viewed any speed higher than Mach 1.6 as unnecessary because at that time, for aerodynamic reasons, all dogfights took place at subsonic speed and there was a significant technical and financial price for flying at Mach 2+ They claimed the reduced top speed was the only area where the Red Bird's performance was lower than the Blue Birdís, and that by limiting the Red Bird to Mach 1.6 the fighter would be much less expensive, lighter, and have better performance. Sprey and Boyd also decided to remove the radar and the associated radar-guided missiles which they considered unreliable, further reducing the Red Bird's weight. They estimated the Red Bird would weigh about 23,000 pounds and would provide air-to-air performance equal to the Blue Bird for a far lower unit cost. Additionally, they felt these changes would make the Red Bird more reliable. This seemed to be classic example of "out of the box" thinking, but what Boyd and Sprey were actually doing was not meeting a requirement but changing it. Boyd briefed some members of the Air Staff on the Red Bird concept, while Sprey briefed General Ferguson at Air Force Systems Command, but there were no changes in the Blue Bird.
