"Coincidently, Bruce Orriss sent along a couple of photos from the past of this same airplane being rebuilt at Urbana, that being 44-85813 when it was operated as a five-engine test bed for Curtiss-Wright. Interesting story about these test beds, particularly the one operated by Curtiss-Wright and the one operated by Pratt & Whitney. Both had significant airframe mods done by Boeing that primarily involved moving the cockpit aft by four feet, strengthening the fuselage structure with additional framework and thicker skin, and constructing a fuselage firewall to accept the test engines."
Maroderr (см комментарий ниже) прав, тестировали двигатели.
Слоупок репортед ин. Как писалось выше, испытывался турбовинтовой двигатель XT-35 "Typhoon". 1948 год. На пикче выше, самолет летит на одном этом двигателе, винты триммированы для уменьшения сопротивления.
Maroderr (см комментарий ниже) прав, тестировали двигатели.