Focke-Wulf Fw 190 B and C

Focke-Wulf Fw 190 B / C
Fw 190 V18 / U1 (model picture)
Type:	High altitude fighter prototype
Design country:	German Empire
Manufacturer:	Focke-Wulf

The Focke-Wulf Fw 190 B and C were prototypes of a planned high-altitude fighter, derived from the Fw 190 A.

Fw 190 B

Early on in the development and testing of the Fw 190 A, it became apparent that the BMW 801, with excellent performance overall, recorded a significant drop in performance at altitudes above 6000 meters. The associated collapse in flight performance at high altitudes became increasingly noticeable from the second half of 1942 at the latest, when ever greater altitudes had to be reached in the aerial battles. This development gave the impetus for the development of the Fw 190 B, which, with a turbocharged BMW 801 and an enlarged wingspan, should have improved altitude performance. Preliminary work for this project had already been carried out in part with the Fw 190 A-3 / U7, for which a wing with a larger span had been developed (12.3 m). Since the BMW 801 was not originally developed for use in a fighter aircraft, it also did not have a loader whose performance at greater heights was comparable to that of e.g. B. was comparable to the V-engine DB 605, which gave the Messerschmitt Bf 109 a significantly better high-altitude performance compared to the Fw 190 A. Attempts to relocate the intake ducts on the Fw 190 A-3 / U7 test models to the outside, where there was a better damming effect, were satisfactory, but were only delivered in small numbers as conversion kits to the front units on the English Channel . The BMW 801 J was originally planned as the drive for the B series of the Fw 190. Of this only German aircraft engine with exhaust gas turbocharger, which was built at least in small series, only 310 units were built, for example, in the V-type of the Junkers Ju 388 (the German aircraft engines that were built in series were otherwise without exception via mechanical loaders that were driven directly by the engine and connected to it by a separate clutch). In total, only five B-0 and B-1 model aircraft were produced, three of which were equipped with a pressurized cabin. Even the versions of the BMW 801 equipped with special high-altitude loaders did not reach series production in time during the war, so that the planned high-altitude version Fw 190 B could not be implemented.

Fw 190 C

The Fw-190-C series (Höhenjäger 2) should also lead to a fighter suitable for high altitudes, but now using the powerful Daimler-Benz DB-603 engine . This large displacement (44.5 l) hanging 12-cylinder V-engine with centrifugal charger was technologically based on the DB 601 . The engine belonged to the 2000 hp class and - like the DB 605  - retained its performance better than the BMW 801 even at higher altitudes . The first test samples V13, V15, V16 and V18 were used exclusively for engine testing. At the beginning of March 1942 the V13 (W. Nr. 0036, SK + JS) with a DB-603-A-0 engine went into flight tests. The engine - like the Jumo 213 of the later D-9 variant - was provided with a ring cooler, which gave the machine the appearance of a machine driven by a radial engine. In this way, it was possible to adapt the V-engine to the Fw 190 airframe with reasonable design effort. In addition to the ring cooler, the air flow of which could be regulated by movable cooling flaps, the test samples had an oil cooler underneath the engine, which at that time could not be integrated into the ring cooler.

Fw 190 V13, V15 and V16

Side view of the Fw 190 V13. The machine had a construction called the “stove pipe” in-house, in which the charger air was taken in at the bow between two segments of the ring cooler and fed through a long pipe under the engine cover to the mechanical charger of the DB-603 engine (recognizable by the bulge-shaped cover the place of the loader hood on the V15 and V16). However, this construction, which was expected to provide better aerodynamics than an external intake scoop, did not prove itself due to its low jam effect.

Side view of the Fw 190 V15, which was equipped with an external intake hood for the supercharger air.

The V13, V15 and V16 were tested without any armament, although firing channels were already present in the fairing of the ring cooler. In order to make the aerodynamics of the machines particularly efficient, Focke-Wulf decided not to use a scoop on the side of the fuselage for the V13, as was the case with the Bf 109, but within the engine casing, as in the case of the star-powered variants of the Fw 190 remove. For this purpose, a long pipe (internally called the “stove pipe”) led from the ring cooler, where it protruded between two cooler segments and took in the supercharger air, through the engine compartment to the centrifugal supercharger, which was located on the left rear of the engine. In the flight tests, however, this solution was unsatisfactory because it impaired the altitude performance too much (for example, the full pressure height of the engine with the intake pipe on the inside was 1500 m below the full pressure height with the intake hood on the outside) and the oil cooler had too little space and was therefore not big enough could be interpreted. When testing the V15 and V16 showed that the external intake hood had no negative effects on the top speed despite the additional resistance, the solution with the internal intake of the charger air was abandoned.

The performances flown with the prototypes in the test showed significant improvements compared to the radial engine variants of the Fw 190, especially at higher altitudes. The V13 reached a speed of 500 km / h on April 9, 1942 at an altitude of 500 m. On April 18, the same machine reached  a speed of 650 km / h with combat performance and a speed of n = 2500 / min at an altitude of 5950 m. A little later, this value was improved to 663 km / h on the 13th flight by chief test pilot Hans Sander.

When the machine was transferred to Rechlin for technical testing at the end of April 1942 , it became clear that the flight characteristics of the V13 hardly differed from those of the star-engine-powered versions of the Fw 190. Due to the longer fuselage, only larger sideslip angles resulted when the rudder was not correctly inserted, due to the lower stability around the vertical axis. In spite of the sweeping V-engine, the visibility conditions on the landing approach were not worse due to the higher rate of descent and the associated steeper approach angle of the V13 compared to the star-powered versions.

On July 30, 1942, the V13 was so badly damaged on its 35th flight after an engine failure during the following emergency landing that the machine was abandoned. The further flight tests took place with the V15 (W. Nr. 0037, CF + OV), which was equipped with an external intake hood for the charger air from the beginning. With this design, the V15 showed significantly better flight performance than the V13 at the Rechlin test site (where the machine arrived on May 19, 1942). The maximum speed of the V15 with combat performance (again a DB 603 A-0 provided the drive) at an altitude of 6950 m was 696 km / h, while at an altitude of 400 m a maximum speed of 575 km / h could be flown. The aircraft had a takeoff weight of 3607 kg on these flights, of which 27 kg was ballast weights. The machine was also filled and polished in order to achieve the smoothest and most streamlined surface possible. According to Focke-Wulf, a further increase in speed would have been possible by converting the machine to a narrower engine cowling. The V15 was used for various tests until the end of the war and was captured in good condition by American troops in Göttingen on April 18, 1945.

The V16 (W. Nr. 0038, CF + OW) made its maiden flight in the summer of 1942, but little is known about the testing of the machine at Focke-Wulf. On August 2, 1942, it was handed over to Daimler-Benz in Stuttgart-Echterdingen for further engine developments, where flight performances very similar to those in Rechlin were flown in extensive flight tests. The V16 reached  a maximum speed of 724 km / h with the DB 603 A with normal loader in emergency power ( n = 2700 / min) at an altitude of 7000 m. After Daimler-Benz installed the new G-Lader (the engine designation was changed to DB 603 G), the machine reached a speed of 722 km / h at an altitude of 9,000 m. The climb rate of the V16 was around 17.5 m / s near the ground, a value that could be kept constant up to a height of around 4.5 km. Comparisons with the Junkers Jumo 213 later built into the Fw-190-D series also showed that the DB 603 gave the Fw 190 a more constant climbing ability on the ground, as it maintained its performance better in the lower altitude band.

The V16 was badly damaged in a bomb attack on Echterdingen on August 14, 1944. It is not entirely clear whether it was rebuilt afterwards and used for further tests, but there is a note from December 1944 about the machine in the Daimler-Benz documents, which lists it as a converted one.

Fw 190 V18 / U1 - Tests with turbochargers

Side view of the Fw 190 V18 / U1 with the Hirth exhaust gas turbocharger, the great air resistance of which made the additional engine power practically ineffective at great heights.

The next prototype of the Fw 190 C-series was the V18 (W. Nr. 0040, CF + OY), after the V17 (W. Nr. 0039, CF + OW) after a decision of the general Luftzeugmeister Milch for testing the Junkers- Jumo 213 engine had been withdrawn. The V18 was the first prototype to be equipped with various equipment planned for the high altitude fighter variant of the C series, such as a pressurized cabin, extended wings, a DB-603-G engine and a four-blade propeller. In the V18 / U1 conversion state, the machine was additionally equipped with a Hirth 9-2281 exhaust gas turbocharger under the rear fuselage. In order to test this and other exhaust gas turbochargers, the prototypes V29, V30, V32 and V33 were built after the V18, all of which corresponded to the conversion status of the V18 / U1.

The V18 / U1, nicknamed “Kangaroo” by the test pilots, had an output of 1,600 hp at an altitude of 10,700 m thanks to the turbocharger with a DB-603-A engine. In order to maintain directional stability despite the air inlet below the fuselage, the V18 / U1 had a greatly widened vertical stabilizer, which was even wider than that of the later D variant of the Fw 190 (and was later to be adopted for the Ta 152 ). The engine exhaust gas was led from the exhaust pipe through long pipes over the wing roots to the turbocharger, from which the compressed air was returned to the engine. This complex arrangement, which - in contrast to the American Republic P-47 Thunderbolt  , for example - could not be fully accommodated in the fuselage for reasons of space, together with the voluminous air inlet under the fuselage caused a high additional resistance. As a result, and due to the weight of the system, the machine did not show any additional performance in the test that would have justified the additional construction effort for a series.

On the other hand, the testing of the prototypes V13, V15 and V16 was so successful that the series production of the sub-variants Fw 190 C-1 and C-2 was already planned. While the C-1 was designed without a pressurized cabin, the C-2, as a real high-altitude fighter, should be equipped with one. Both versions should be equipped with two 13 mm MG 131s above the engine, which shoot through the propeller circle, as well as two MG 151/20  E units in the wing roots, which also shoot through the propeller circle . In addition, the use of the V-engine made it possible to mount a motor cannon, either a 20 mm MG 151/20, a 30 mm MK 108 or a 30 mm MK 103 . Since it was also possible to install two 20 mm MG 151/20 in the outer wings, there would have been the possibility of extremely heavy armament that would have enabled the Fw 190 C to fight heavy bombers.

The LC 21 delivery schedule of December 1942 provided for the series production of 727 C-series machines between March 1943 and March 1944. For reasons that are no longer fully comprehensible today, however, this project found no support at crucial points in the RLM and the C-series of the Fw 190 was subsequently discontinued at the beginning of 1943 and ultimately never implemented.

literature

• Manfred Griehl, Joachim Dressel: Focke-Wulf FW 190, Ta 152: Jäger, fighter-bomber, tank destroyer. Motorbuchverlag, Stuttgart 1995, ISBN 3-613-01681-8 .
• Dietmar Hermann: The Focke-Wulf high altitude hunters. From the 1st Höhenjäger to the Fw 190 H. 1st edition. 2002, ISBN 3-925480-69-2 .

Web links

• 190 B, C. In: focke-wulf190.com. Retrieved April 5, 2013 . 
• Focke-Wulf Fw 190. In: klueser.eu. Retrieved April 5, 2013 . 

Individual evidence

1. ↑ Kyrill von Gersdorff, Kurt Grasmann, Helmut Schubert: Aircraft engines and jet engines.
2. ^ Aircraft Classic 2/2005, German aircraft types: Fw 190 B / C / D - Höhenjäger. Pp. 41-44.
3. ↑ The prevented challenger. In: Flugzeug Classic 4/2009. Pp. 24-31.
4. ↑ The prevented challenger. In: Flugzeug Classic 4/2009. P. 27.
5. ↑ The prevented challenger. In: Flugzeug Classic 4/2009. P. 30.
6. ↑ The prevented challenger. In: Flugzeug Classic 4/2009. P. 30.