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Fw 190 A-4

In July 1942, the A-3 was replaced on the production lines by the newer Fw 190A-4 version.
The main difference was an BMW 801 D-2 engine adapted to use with a MW 50 system for short period engine power increase by injection of a water-methanol (methyl alcohol CH3OH) mixture in the proportion of 1:1.
In this way it was possible to raise engine power to 2100 kW for 10 minutes, after which a high probability of engine failure prevented longer use.
Due to delays in MW 50 device production, this system was not mounted on the Fw 190A-4 engines, which had the capability to accept this system.
It was not used and only A-8 and later series planes would use the advantages of this invention.

Another difference in the A-4 variant was the replacement of the FuG 7a radio set by the more modern FuG 16z.
A less important change was that the vertical line antenna mount was placed on the fin; this made it easier to distinguish between A-4 and A-3 versions. In the case of the A-2 and A-3 versions, it is often difficult to tell them apart.

During production, in some Fw 190s another modification was applied.
In place of the ventilation slots, engine cowling shutters controlled from the cockpit were installed.
The pilot could precisely control the engine temperature by regulation of the shutters.

Most Fw 190A-4 planes were used with reduced armament, without MG FF cannons.
Trials with different variants of armament and equipment, generally with Umrustbausatz kits produced the following versions:

Fw 190A-4/U1 - bomber-fighter with an under-fuselage mounted ETC 501 bomb rack and reduced armament (without MG FF cannons). As a result of small deliveries of BMW 801 D-2 engines in the autumn of 1943, several dozens of these planes got older C-2 version engines

Fw 190A-4/U3 - bomber-fighter with armament as in the U1 version, but with BMW 801 D-2 engine. Planes for night operation got a landing light, mounted in the leading edge of the left wing root. Designation was later changed to F-1 and in the future the plane was developed as a new attack Fw 190F version

Fw 190A-4/U4 - reconnaissance fighter with two Rb 12.5/7x9 cameras and without MG FF cannons

Fw 190A-4/U8 - long range fighter-bomber with two drop tanks of 300 litre capacity each, mounted under the wings (on the VTr-Ju 87 racks produced by Weserflug company, with duralumin fairings); bombs were placed on the under-fuselage ETC 501 rack. In an attempt to reduce weight, only two MG 151/20 E cannons were retained. This modification was a prototype of a new fighter-bomber Fw 190G version and its first variant (G-1) simultaneously. There also existed a transitional variant similar to the U8 (probably in one copy) with modernized V. Mtt-Schlos type racks for underwing fuel tanks; armament: 2x1 MG 17 and 2x1 MG 151/20E.

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Fw 190 A-8

A new model with different equipment.
Most important were parts of the MW 50 injection system, used for short term engine power boost. A cylindrical tank of 118 litres capacity was mounted in the rear fuselage.
In an emergency, it could be used as additional fuel tank.

The MW 50 tank installation shifted the centre of gravity backward and, as a cure, the under-fuselage mounted ETC 501 bomb rack was moved 20 cm forward. This rack became a standard from the A-8 model.

The plane was equipped with a FuG 16 ZY radio set that despite the circular radio navigation antenna Morane antenna, was mounted under the left wing.

The outstanding element for differentiation between the A-7 and A-8 is also the Pitot head moved from mid-wing leading edge to right wing tip.

The Fw 190A-8, like previous models, could be equipped with different Rustsatz kits: R1, R2, R3, R4, R6, R7, R8, R11, R12; but R1, R3 and R4 were abandoned shortly thereafter and generally R2, R6, R7 and R8 kits were used. Some of the R11 and R12 modifications produced in small quantities had small differences in the equipment (e.g. MG 131 machine guns tube was covered by a plate for reflection limitation, some got more the more efficient BMW 801 TU engines and FuG 125 Hermine radio navigation device).

Apart from the previously described variants, A-8/F-8 series airframes were often used for different armament and equipment testing. These planes also tested several different engines. Unfortunately, only a small part of the documentation concerning these tests survived, making it impossible to describe in detail all of the modifications and resolve some the contradictory information. In spite of this, we know of the following armament modifications:

SG 113 Zellendusche - 3-tube battery based on the MK 103 cannons mounted in the rear fuselage. Firing was made by a photosensor impulse. - SG 117 Zellendusche - 6-tube modification of the previously described battery.

Rohrblock 108 - similar construction with 7 tubes based on the elements of the MK 108 cannon, fired by photosensor impulse. Probably, it consisted only of MK 108 cannons barrels with a single cartridge; after firing of the first barrel others were fired automatically by the recoil force of previous barrel. This kind of armament was used for bombers interception and was tested on the Fw 190A-8 (W.Nr. 733713), prototype designation V74.

SG ...? Harfe - set of 3-4 15-barrel, unguided 20 mm missile launchers mounted in the rear fuselage on both sides. At least one prototype plane had such armament and was presented to Gen. Adolf Galland.

Ruhrstahl X-4 (Ru 334) - wire-guided rocket missiles mounted on underwing racks, probably of the ETC 503 type. This armament was developed for destroying ground targets (tanks) and for bombers fighting (different warhead). It was tested on the F-8 version plane.
From 1944, production of fighter planes was sharply increased in the so-called Jagernotprogramm. This required higher production coordination and development of a cooperative network. As a result, the Fw 180 A-8 was produced in mass numbers in nearly all Focke-Wulf affiliated factories (production started also in Cottbus, Sorau, Poznan). A licence was sold to the NDW (Norddeutsche Dornier Werke) factory in Wismar. Smaller factories performed repair work and recycled the planes withdrawn from service units. They also produced smaller aeroplane parts. Special coordination committees secured efficient work systems and continuous parts delivery.

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Fw 190 A-9

Next and last production series of the A version aircraft was the Fw 190A-9. Previously, it was thought this plane would have been powered by a 1765 kW (2400 hp) BMW 801 F engine. But the BMW factory had not started production of these engines in time and, as a replacement, the 1470 kW (2000 hp) BMW 801 S engine was used.

These engines were delivered as a power unit BMW 801 TS together with a more efficient radiator and bigger circular armoured oil tank mounted in front of the engine. The cowling length increased by some 30 mm. A more efficient, 14-blade fan replaced the previous 12-blade unit for more efficient cooling. Also, the thickness of the armour on the oil tank increased from 6 to 10 mm.

A new broad-chord wooden propeller with a diameter of 3500 mm should have been used to match the increased engine power. The new propeller was manufactured by Heine or Schwartz companies, but for unknown reasons the majority of the A-9 planes (as opposed to F-9) had the metal VDM 9-12176 A propellers, as used in the previous version.

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Fw 190 A-5

On the basis of data collected during tests of the experimental Fw 190A3/U1, Blaser's designer team became convinced that the planned additional armament would move the plane centre of gravity forward.
The best solution to offset this was to move the engine forward. This was done with a 15 cm steel tube engine mount extension.
This change (new engine mount) was introduced on the all production lines. It also led to an increase of the plane length to 9.10 m and gave life to the new Fw 190A-5 variant that from November 1942 replaced previous the A-4.

The A-5 also introduced small changes in the equipment (e.g. a new electrical artificial horizon and modernized oxygen respirator, and wide use of the FuG 25a IFF device).
Radio equipment in the rear fuselage section was slightly moved back and the compartment cover was enlarged. Standard armament did not change and it remained 2x1 MG 17, 2x1 MG 151/20 E , 2x1 MG FF.
Proper airframe design provisions meant that the Fw 190A-5 plane was prepared from the beginning to accommodate a large number of Umrustbausatz kits:

Fw 190A-5/U1 - similar (with extended engine mount) to A-4/U1 airplane, temporary powered by a BMW 801 C-2 engine

Fw 190A-5/U2 - long range fighter-bomber plane adapted to the night operation; it was fitted with anti-reflective strips over engine exhaust pipes on both sides. Mounted under the fuselage, an ETC 501 bomb rack for 250 or 500 kg bombs was added, additional fuel was placed in two external tanks of 300 l capacity each mounted under the wings on V.Mtt-Schloss (Verkleidetes Messerschmitt Schloss) shackles. In the wing leading edge an EK 16 camera and a doubled landing light were installed; the MG FF cannons were deleted in this modification.
Based on this version, a night fighter with FuG 217 Neptun J-2 radar was built. However, number of planes built is unknown; the only known specimen of this variant had no bomb rack, camera or landing lights.

Fw 190A-5/U3 - fighter-bomber with the ETC 501 bomb rack and without MG FF cannons. After a change of designation this was serially produced as Fw 190F-2. There was also a desert variant with dust filters designated as A-5/U3/tp (F-2tp).

Fw 190A-5/U4 - reconnaissance fighter fitted with two Rb 12.5/7x9 mm cameras and reduced armament (2x1 MG 17 and 2x1 MG 151/20 E); produced also in a desert variant designated A-5/U4/tp.

Fw 190A-5/U8 - long range fighter-bomber with two underwing mounted external fuel tanks (capacity 2x300 litres) and an under-fuselage mounted ETC 501 bomb rack; armament consisted of only two MG 151/20 E cannons. It was developed into Fw 190G-2 plane and later serially produced.

Fw 190A-5/U9 - experimental plane with heavier armament, it was fitted with 2x1 MG 131 13 mm machine guns in place of MG 17 guns in the fuselage; in the wings the MG FF cannons were replaced by MG 151/20 E cannons. Only two were built (W.Nr. 150812, and 150816).
The W.Nr 150816, BH+CF plane was later used as test bed for more powerful BMW 801 engine versions.

Fw 190A-5/U10 - experimental plane (only two built W.Nr. 150861 and 150862). It was used as a test bed for a strengthened wing adapted to serial application of heavier armament, generally 20 and 30 mm cannons.
Armament consisted of 2x1 MG 17 in the fuselage and 4x1 MG 151/20 E in the wings, later become a standard for A-6 version.

Fw 190A-5/U11 - attack aircraft with two 30 mm Rheinmetall-Borsig MK 103 cannons mounted in underwing pods; only one plane existed (W.Nr. 151303, RG+ZA). This kind of armament became later standard as Rustsatz 3 (R3) kit.

Fw 190A-5/U12 - proposal for heavier armament consisting of six MG 151/20 E cannons. They were mounted under the wing in two additional WB 151/20 pods with two cannons in each pod; complete armament could be 2x1 MG 17, 2x1 MG 151/20 E and 2x2 MG 151/20 E. It was also a model for Rustsatz 1 (R1) kit for Fw 190A; two planes (BH+CC, W.Nr. 150813 and BH+CD, W.Nr. 150814) with such armament were completed.

Fw 190A-5/U13 - three prototypes (V42, W.Nr. 151083, GC+LA; V43, W.Nr 150817, BH+CG and V44, W.Nr. 150855) built, long range fighterbomber with two underwing V.Fw Trg. (Verkleideter Focke-Wulf Trager) bomb racks, adapted for carriage of 300 litre capacity fuel tank or 250 kg bomb.
The plane was equipped with an automated pilot device and application of knifes for barrage balloons lines cutting on the wing leading edge was considered; one plane was experimentally equipped with a lacunar exhaust flame damper (GC+LA?). Armament consisted of two MG 151/20 E mounted in the wing roots. Plane was later produced under designation Fw 190G-3.

Fw 190A-5/U14 - torpedo plane adopted for transportation of one aerial torpedo LT F 5b mounted on the under-fuselage ETC 502 rack; plane had an enlarged fin (similar to Ta 152) and heightened tail wheel strut to eliminate the possibility ground contact by the torpedo; armament consisted of only 2x1 MG 151/20 E cannons. Two planes were tested TD+SI, W.Nr. 150871 and TD+SJ, W.Nr. 150872.

Fw 190A-5/U15 - experimental plane adopted for transportation of the unpowered Blohm und Voss 246 Hagelkorn (LT 950) flying bomb for destroying of naval targets, radio controlled by an Askania company produced ALSK 121 device. Extensively tested during second half of the 1943, later in the test program an A-8/F-8 series plane (W.Nr 130975) was also included, but tests were cancelled shortly after it was found that because of poor construction, the BV 246 had frequent defects.

Fw 190A-5/U16 - prototype of a fighter plane with heavier armament (W.Nr. 130975), for destruction of bomber formations. The MG FF cannons were replaced by heavier 30 mm cannons Rheinmetall-Borsig MK 108. This armament was later standardized as the Rustsatz 2 (R2) kit.

Fw 190A-5/U17 - fighter-bomber with under-fuselage mounted ETC 501 bomb rack and four underwing mounted ETC 50 bomb racks (2x2 50kg bombs). With A-5/U3, this variant was a model for the Fw 190F attack aircraft; basic version for the later Fw 190F-3/R1 variant. Armament was standard without MG FF cannons. Also used in a desert modification.
Finally, in response to the intensifying of the Allies' bombing, numerous Fw 190A-5/R6 planes belonged to units operated in Reich defence system (Reichsverteidigung) have been found.

As an interesting detail, we must mention the existence of a Fw 190A-5 plane with external turbosupercharger inlets. The engine cowling with these inlets was proposed as an alternative, but was not used widely because of higher induced aerodynamic drag.

There exists also a photograph of an A-5 fighter from a II./JG 54 unit deployed to the Eastern Front temporary adopted to bomber missions by four (2x2) under-fuselage mounted ETC 50 bomb racks.

In the autumn 1943, one A-5 plane (W.Nr. 157347) were used as the V45 prototype for tests of the GM 1 system that by injection of pressurized nitrogen monoxide as an oxidant to increase engine efficiency at high altitudes. This device was later standardized as the Rustsatz 4 (R4) kit.

In connection with the planned 1765 kW (2400 KM) BMW 801 F engine production to be used for A-9 and A-10 series planes, in December 1943 Focke-Wulf was ordered to prepare an A-5 airframe (W.Nr. 410230) as the V34 prototype for tests with the experimental BMW 801 V 85 engine; however, we have no evidence that the engine was supplied and mounted on that particular Fw 190 plane. Serial production of BMW 801 F engines never started and A-9 series planes had TS/TU engines mounted.

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Fw 190A-6

The main difference of this variant from the previous was the standardized mounting of MG 151/20 E cannons.
For this to be possible, it was necessary to redesign the wing for the heavier cannon mount and carriage of a larger ammunition box.
Experience obtained during Fw 190A-5/U9 and U10 tests was incorporated in this type.
Reinforcements and sockets were made in such a way that serially produced wings would be adapted for internal installation of either 20 or 30 mm cannon ammunition boxes or for installation of underwing armament with the ammunition box installed inside the wing.
Proper electrical connections were also provided for the cannons.

The manufacturer started serial production of the FuG 16 ZE radio with an additional radial antenna for radio navigation purposes placed under the rear fuselage. This antenna was used also in the some A-5 planes.

Standard Fw 190A-6 armament consisted of 2x1 MG 17 machine guns and 4x1 MG 151/20 E cannons. Some planes mounted ETC 501 bomb racks for transportation of an additional fuel tank (300 l capacity), these were not distinguished by separate designation.

Unlike other versions, models with different armament or equipment received designations as Rustsatz kits. A lot of these designations had not been previously used:

Fw 190A-6/R1 - attack fighter with armament increased to six cannons and two machine guns (2x1 MG 17, 2x1 MG 151/20 E and 2x2 MG 151/20 E), by mounting of the WB 151/20 underwing pylons with cannons. This modification was based on the A-5/U12 version. In spite of previous plans, only a few planes with this armament were in Luftwaffe service units (e.g. in JG 11).

Fw 190A-6/R2 - equivalent to the A-5/U6 model, armament: 2x1 MG 17 machine guns, 2x1 MG 151/20 E and 2x1 MK 108 cannons; not serially produced.

Fw 190A-6/R3 - equivalent to the A-5/U11 model, armament: 2x1 MG 17 machine guns, 2x1 MG 151/20 E and 2x1 MK 103 cannons; not serially produced.

Fw 190A-6/R6 - plane with standard armament and the addition of W.Gr. 21 missile launchers.

Fw 190A-6/R2/R6 - plane adapted for destruction of bomber formations, with increased armament and missile launchers, only one prototype, V51 (W.Nr. 530765), built. Total armament consisted of 2x1 MG 17, 2x1 MG 151/20 E, 2x1 MK 108 and 2x1 W.Gr. 21.

Fw 190A-6/R7 - armoured fighter with standard armament; in service with Reich defence units; often with additional 300 l capacity fuel tank mounted on the ETC 501 bomb rack.

Fw 190A-6/R8 - the Rustsatz kit made by application of both R2 (MK108 ) kit and R7 kit (armour), often machine guns in the fuselage were removed; efficient as a fighter against American bomber aircraft.

Fw 190A-6/R11 - all weather and night fighter, with anti-reflection strips, landing light, autopilot device PKS 12 and heated windscreen windows. Some planes mounted a FuG 217 Neptun J-2 radar. Generally, these planes used dropable fuel tanks mounted on the ETC 501 bomb rack.

Fw 190A-6/R12 - the Rustsatz kit created by application of both R2 and R11 kits. Apart from this modification, one or two planes experimentally mounted more the higher power BMW 801 TS engine with three blade wooden VDM propeller with blades of larger area.
The aircraft with code letters VO+LY had an additionally armoured radiator and oil tank; it's armament was reduced to two MG 151/20 E cannons mounted in the wing roots.