FX Studies
April 1965 - FX studies begin. Air Force Systems Command studies end up recommending a 60,000lb VG design with air-air and air-ground capability.
December 1965 - RFP issued to 13 companies for concept formulation for a TSA (Tactical Support Aircraft)
March 1966 - 8 bids recieved. All were VG designs except Northrop. Boeing, North American Rockwell, Lockheed awarded contracts. Vought (V-483), McDonnell-Douglas (Model 199), Grumman (G-300?), Northrop make unsuccessful bids. McDonnell-Douglas carries on in-house studies on Model 199 from April to December 1966 without funding, as does Grumman. Rockwell work on a primary VG design and a second, higher risk blended fixed wing design, which seems to promise to make VG unnecessary. A closely related fixed wing design (NR-323) was submitted to the VFX competition, despite having little chance of succeeding, perhaps to gain experience for the FX program.
Air Force were unimpressed with all three designs from chosen contractors.
USAF runs its own Concept Formulation Study from Autumn 1966 to Autumn 1968. John Boyd contributes a series of tradeoff studies and in early 1967 arrives at the 40,000lb, manouvreable "Blue Bird" concept.
August 1967 - RFP for a Fighter, Experimental (FX) concept formulation sent to 7 contractors. Thanks to John Boyd, a more manouverable 40,000lb plane was envisaged. McDonnell-Douglas and General Dynamics issued contracts. North American, Lockheed, Fairchild-Hiller and Grumman all participated using company funds. Grumman's FX studies included Model G-399.
Ran through to May 1968.
General Dynamics recommended both fixed and variable geometry designs, while McDonnell-Douglas recommended fixed wing, two engines, single crew.
May 1968 – concept definition agreed. RFP for FX contract definition issued to McDonnell-Douglas, North American, Grumman, General Dynamics, Lockheed, LTV, Fairchild-Hiller, Boeing.
August 1968 – Only 4 serious bids were received; North American (NR-335), McDonnell-Douglas (Model 199B), Fairchild-Hiller and General Dynamics. General Dynamics was eliminated, and contracts were awarded to the remaining three. F-15 designation was reserved for FX winner. Rockwell's wing design had more than 8,000 hours of wind tunnel testing behind it.
October 1968 – participants asked to consider Navy adaptability.
From July to December 1969 ASD (Aeronautical Systems Division) evaluated the three proposals. McDonnell-Douglas was announced the winner December 23, 1969.