 Design work was begun in 1943, much of it being carried out by French technicians working for Focke-Wulf at Châtillon-sous-Bagneux near Paris, with contracts for design and construction of major components being awarded to German, French, and Italian companies in an attempt to speed the process and begin construction of prototypes as soon as possible.The Ta 400 had a shoulder-mounted wing with 4° dihedral, with a long straight center section extending to the middle engine on each wing, and highly tapered outer wing panels.It had twin vertical stabilizers mounted at the tips of the tailplane.