beechcraft Xa38 grizzly
Northrop Xb35
Vultee Xp54 Swoose Goose
Curtiss Wright Xp55 Ascender
Northrop Xp56 Black Bullet
Mc Donnell Xp67 Bat
North American Xp82 Twin Mustang
Douglas XB-42 Mixmaster
Boeing XF8B
Curtiss XP62
