B747-200 simulator:-
Wt 280,000kgs X-wind 10 kts, temp +5C Nacelle anticing 'on', sea level airport (no terrain).
No 1 failed at V1 +5kts and No 4 failed at Vr.
Gear up and climb of 200-300fpm to 1000'aal. Level flight clean-up.
B747-400 simulator:-
Wt 380,000kgs, wind calm, temp +28C sea level airport (no terrain).
No 4 failed at V1+5kts and No 3 failed at 800' rad.alt.
Slow descent ( trading alt. for accel.) and flaps retracted at bug speed -5kts. Lowest alt. reached 400' rad.alt. Accelerated to 280 kts to turn into live engines (not possible at Flaps up speed).
In both cases, fuel jettison (2000kgs per min.) not used until after flaps retracted.
For either 747 types, flight following failure of both adjacent engines at between V1 and Vr would probably be impossible - but I stand to be corrected by anyone who has had time in the sim to experiment.
