The A-5 was developed after it was determined that the Fw 190 could easily carry more ordnance. The engine was moved forward by 15 cm, and the aircraft was equipped with the BMW 801 D-2 engine, rated at 1,700 PS (1,677 hp, 1,250 kW). Some A-5s were tested with the MW 50 installation: this was a mix of 50% methyl alcohol and 50% water which could be injected into the engine to produce a short-term power boost to 2,000 PS (1,973 hp, 1,471 kW) but this system was not adopted for serial production. New radio gear, including FuG 25a Erstling IFF and an electric artificial horizon found their way into the A-5. The A-5 retained the same basic armament as the A-4. The A-5 too, saw several Umrüst-Bausätze kits. The U2 was designed as a night Jabo-Rei and featured anti-reflective fittings and exhaust flame dampeners. A centre-line ETC 501 rack typically held a 250 kg bomb, and wing-mounted racks mounted 300-litre drop tanks. A EK16 gun camera, as well as landing lights, were fitted to the wing leading edge. The U2 was armed with only two MG 151 cannons. The U3 was a Jabo fighter fitted with ETC 501s for drop-tanks and bombs; it too featured only two MG 151s for armament. The U4 was a "recon" fighter with two RB 12.5 cameras and all armament of the base A-5 with the exception of the MG FF cannons. The A-5/U8 was another Jabo-Rei outfitted with SC-250 centre-line mounted bombs, underwing 300-litre drop tanks and only two MG 151s; it later became the Fw 190 G-2. A special U12 was created to fight American and British bombers, outfitted with the standard MG 17 and MG 151 but replacing the outer-wing MG-FF cannons by two underwing gun pods containing two MG 151/20 each for a total of two machine guns and six cannons. The A-5/U12 was the prototype installation of what was known as the R1 package from the A-6 onwards. The A-5/R11 was a night-fighter conversion fitted with FuG 217 Neptun (Neptune) radar equipment with arrays of three antennae vertically mounted fore and aft of the cockpit and above and below the wings. Flame dampening boxes were fitted over the exhaust exits. There were 1,752 A-5s built from November 1942 to June 1943.