One of the main problems that the project faced was with engines - the pulse jets didn't operate well at high to medium altitudes (where most combat would take place) due to the lower air pressure. The engines also generated a huge amount of noise which could be heard miles away, making them unsuitable. The excessive vibration of the engine would be compounded by the fact that in a twin-engined craft the two pulsejets would be producing oscillations in their own unique thrust cycle, which would cause instability due to asymmetry as well as resonance.
