John,
Best of luck! ...Better luck than the first one or two flight attempts on the original... I think it broke the first test pilot's back on takeoff run. My memory serving me?
It might not be, as I seemed to recall this as XP-56, Black Bullet.
The USAAF (US ARMY Air Force, for you of the blue-suit generation) requested three highly experimental design proposals at the time. One is in the avatar image on Doc's post.
I think that was XP-52 ? Swoose Goose ? twin boomer with a wing planform like Vultee Vanguard - sweepback LE to the booms, then straight out to the tip, and swept forward TE all the way. There may be a three view of this one in one of the Wylam plans books. Too lazy to confirm that just now...
The third one - I forget its XP-designation, but suggest care when you pronounce its name - Asc-ender - oops, that's Ascender. Swept wing canard design with its Allison 1710 at the back of the wing root as a pusher... OF COURSE the name meant that the plane could climb, don't you dare think otherwise!
Final note on the Black Bullet - there was a series, possibly in the sorely missed Wings/Airpower magazines, about these three X-planes. I have it here somewhere. May have been in Air International, or Aeroplane (both Brit mags)... The Black Bullet's first attempt at flight did not have the bump upper fin area. AsIr, it may have started porpoising on the takeoff run - very short spacing between nose-wheel and mains - almost impossible to even think of catching up with PIO (pilot induced oscillation), flipped and tumbled to a stop. Very short coupled controls and a lot of mass concentrated in the middle obviously could not help stabilize or control such deviation until a lot of speed had developed. It hadn't. Test pilot suffered.
The other two were also pusher engine designs, and both reportedly suffered from lack of adequate cooling, particularly on the ground. Same fate later killed the XP-67 Moonbat. I mean killed it. Hangar fire (when testing?) ended that blended wing/fuselage McDonnel prototype. The blended wing/fuse layout did much better on McDonnel's early Navy jets.
Somewhere on the web there is some motion imagery of the XP-67 in flight. GREAT stuff! Maybe a search on McDonnel XP-67 will find it for you...