PROCUREMENT: New Details About the F-15X That Boeing is Pitching the US Air Force.

The X variant would benefit from upgrades funded by allies who have bought F-15s: Saudi Arabia, Qatar, Singapore and South Korea, which have collectively spent about $5 billion to develop new technology for their jets, the sources said. Compared to the Air Force’s existing F-15s, the new ones would have better flight controls, displays, and radars, and more powerful engines that allow the planes to carry a larger payload.

Like the air-to-air F-15C, and unlike the Strike Eagles, the new F-15X would have just one seat. Large digital display screens would replace the analog dials inside older F-15s. The planes could carry all of the existing equipment, like targeting pods, used across the existing Eagle fleet. The F-15X will also be able to carry anti-ship weapons that allies have paid to test and install. In all, the plane could carry 29,000 pounds of weapons.

The F-15’s range, speed and payload separates it from other fighter jets in the U.S. military. “There’s really nothing like it,” said Richard Aboulafia, vice president for analysis at the Teal Group, a Virginia-based consulting firm.

The F-15C used to be the high end of the Air Force’s old “high-low mix” of Eagles and Falcons. The F-15X might make a nice low end fighter going forward, and could help fill in the range gap left by the F-35’s shorter legs.