the early types, such as the F-15SA Strike Eagle for Saudi Arabia, have included upgrading to FBW. Thrust vectoring Thrust vectoring was originally introduced in the Hawker Siddeley Harrier for vertical takeoff and landing, and pilots soon developed the technique of "viffing", or vectoring in forward flight, to enhance manoeuverability. The first fixed-wing type to display enhanced manoeuvrability in this way was the Sukhoi Su-27, the first aircraft to publicly display thrust vectoring in pitch. Combined with a thrust-to-weight ratio above unity, this enabled it to maintain near-zero airspeed at high angles of attack without stalling, and perform novel aerobatics such as Pugachev's Cobra. The three-dimensional TVC nozzles of the Sukhoi Su-30MKI are mounted 32° outward to longitudinal engine axis (i.e. in the horizontal plane) and can be deflected ±15° in the vertical plane. This produces a corkscrew effect, further enhancing the turning capability of the aircraft. The MiG-35 with its RD-33OVT engines with the vectored thrust nozzles allows it to be the first twin-engined aircraft with vectoring nozzles that can move in two directions (that is, 3D TVC). Other existing thrust-vectoring aircraft, like the F-22, have nozzles that vector in one direction. The technology has been fitted to the Sukhoi Su-47 Berkut and later derivatives. The U.S. explored fitting the technology to the F-16 and the F-15, but did not introduce it until the fifth generation arrived. Supercruise Supercruise is the ability of a jet aircraft to cruise at supersonic speeds without using an afterburner. Maintaining supersonic speed without afterburner use saves large quantities of fuel, greatly increasing range and endurance, but the engine power available is limited and drag rises sharply in the transonic region, so drag-creating equipment such as external stores and their attachment points must be minimised, preferably with the use of internal storage. The Eurofighter Typhoon can cruise around Mach 1.2 without afterburner, with the maximum level speed without reheat is Mach 1.5. An EF T1 DA (Development Aircraft trainer version) demonstrated supercruise (1.21 M) with 2 SRAAM, 4 MRAAM and drop tank (plus 1-tonne flight-test equipment, plus 700 kg more weight for the trainer version) during the Singapore evaluation. Avionics Avionics can often be swapped out as new technologies become available; they are often upgraded over the lifetime of an aircraft. For example, the F-15C Eagle, first produced in 1978, has received upgrades in 2007 such as AESA radar and joint helmet-mounted cueing system,