The best F-4 variant from performance point of view that has flown, is the IAI F-4E-2000 Super Phantom, equipped with PW1120 engines:
IAI installed one PW1120 in the starboard nacelle of an F-4E-32-MC of the IDF/AF (Number 334/66-0327) to explore the airframe/powerplant combination
for an upgrade program of the F-4E, known as Kurnass 2000 ("Heavy Hammer") or Super Phantom and to act as an engine testbed for the Lavi. The
powerplant was more powerful, and more fuel efficient than the General Electric J79-GE-17 turbojet normally installed in the F-4E. The structural
changes included modifying the air inlet ducts, new powerplant attachment points, new or modified powerplant baydoors, new airframe mounted gearbox
with integrated drive generators and automatic throttle system. It also included a modified bleed management and air-conditioning ducting system,
modified fuel and hydraulic systems, and a powerplant control/airframe interface. It was first flown on 30 July 1986.
Two PW1120 powerplants were installed in the same F-4E and it was flown for the first time on 24 April 1987. This proved very successful, allowing the
Kurnass 2000 to exceed Mach 1 without the afterburners, and endowing a combat thrust-to-weight ratio of 1.04 (17 per cent better than the F-4E). This
improved the sustained turn rate by 15 per cent, the climb rate by 36 per cent, medium-level acceleration by 27 per cent and low-level speed with 18
bombs from 1,046 km/h to 1,120 km/h (654 - 700 mph or 565 kts to 605 kts). It was demonstrated at the Paris Air Show in 1987.
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