Tactical (usable) Mach number remained a relatively modest at Mach 0.82 and both German and British test pilots found that it suffered severe controllability problems as it approached Mach 0.86.

The jet engine program was waylaid by a lack of funding, which was primarily due to a prevailing attitude amongst high-ranking officials that the conflict could be won easily with conventional aircraft. Among these was Hermann Göring, head of the Luftwaffe, who cut the engine development program to