12/31/2010. In an effort to evolve a high-performance, long-range escort fighter, two P-61B airframes were selected for modification as XP-61Es. Retaining the R-2800-65 engines of the earlier sub-type, the XP-61E two-seat day fighter had the decking of the fuselage nacelle cut down flush with the wing, and the tandem cockpits enclosed by a hinged single-piece blown canopy (the second prototype having a similar but aft-sliding canopy).
The centre and aft sections of the fuselage nacelle accommodated additional fuel tankage and the nose-mounted AI radar was supplanted by four 0.50 in (12.7 mm) guns, the ventral battery of four 0.787 in (20 mm) cannon being retained. With the end of WW II, the requirement for the two-seat day fighter XP-61E was cancelled, the second aircraft having been written off in a take-off accident on 11 April 1945, and the first prototype was subsequently converted to the XF-15 photo-reconnaissance aircraft.