Sunday, 3 January 2016

Blohm und Voss Bv155 – Some interesting facts. Part 2. Compiled by Alex Halley

Messerschmitt Me 155B DB628 engine high altitude. The boss is on the nose is where the turbocharger TK 11 was installed.

Messerschmitt Me 155B -1 with complex DB 632 engine with propellers contrarotativs

In order to relieve the burden on the already overburdened design office and to accelerate the development, Messerschmitt decided to transfer the Me155B to Paris. Due to various problems work progressed slowly during the rest of 1942. In early 1943 things start to go wrong with the project, while the Focke-Wulf moved well with Ta 152, little had been achieved with the Me 155B. During the first half of 1943, Messerschmitt´s design engineers had evolved over the basic design parameters of a fighter of extreme altitude, under the name of the company as I P1091. In mid-1943 Messerschmitt staff was hesitant as always continuing to build the Me 209H to compete with the Ta 152H and turning the project P1091 as Me Me 155B.

Three views of the P.1091 project with two different stages or Stuffe
Messerschmitt project called P.1091 Stuffe II which consisted of a turbocharged engine DB628 TK 11 or a DB 605A with 2 stages mechanical supercharger, with the first stage fitted around the speeder . Besides the visible elongation of the fuselage.
Messerschmitt project called P.1091 Stuffe III, which consisted to use the DB603 engine with turbocharger TKL 15 or DB632 complex engine and propellers contrarotativ maintaining long fuselage.

Contrary to what was thought at Blohm & Voss, Messerschmitt had done very little work on Me P1091. In the coming weeks the team of Blohm & Voss began to discover this deficiency by themselves. The engineers at Blohm & Voss were not impressed with the Messerschmitt´s drawings, and it was just a matter of how much had to be changed. It soon became apparent that almost all Me 155B systems including wings, fuselage, rudder, turbosupercharger housing and landing gear, were inadequate. In September 1943 the construction of five prototypes was decided, however soon after, Blohm & Voss decided that design problems should be corrected. In late 1943 these had not yet been fixed. At a meeting of high importance to address these problems, Messerschmitt´s responsibles did not attend it. The meeting was finally held, but with little to show despite all the effort. Later Blohm & Voss was also asked for more workers to put project in motion. By November 1943 they were still making changes to design and equipping of weapons. Another change that Blohm & Voss was being contemplated was leaving the complex series of eight from the beginning and then four radiators located on the underside of the wings that Messerschmitt supported, for two large scoop type units mounted above the wings. A model of the design was built and tested in the wind tunnel LFA, but this time, everyone in Blohm & Voss was fed with the lack of cooperation from Messerschmitt. In late 1943 Blohm & Voss officially informed to RLM of their problems with Messerschmitt and implored them to intervene.

Three views of the Me 155B -1 with the complex system with 8 radiators
The BV 155A. Radiators still held above the wings which had been designed by Messerschmitt engineers

With the official transfer of the Me 155B to the Blohm & Voss, the aircraft designation was changed to the BV 155A. Finally freed from the limitations imposed by Messerschmitt, Blohm & Voss immediately points to reassess the new fighter. After a thorough critical examination of the BV 155A, engineers at Blohm & Voss concluded that it would be less expensive and more reasonable to leave this design and take directly the BV 155B. In the meantime he had changed. The most obvious feature of the B series was the re-positioning of the two large radiators which went from being up to be below the wings. This was done to achieve better stability and to improve air flow units. The starboard radiator used to cool the engine lubricants, while the port is used to cool the heat exchanger oil cooler to post cooler (aftercooler) and to cool the air before entering the turbocharger (intercooler ). In the spring of 1944, all major systems are designed, the issue of engine and armament resolved and plans were made to immediately begin construction of the first five prototypes.

In mid-1944 it was proposed that the 5 prototypes BV 155 be completed by the middle of 1945. Meanwhile, Blohm & Voss had been working on the BV P205, this had a different design than BV 155B originally designed to be equipped with an engine Argus As 413 24-cylinder 4000 hp, water cooled. Due to the unavailability of this engine, Bv P205 in its final form, was powered by the DB603U. In the BV P205 were eliminated two wing-mounted radiators, the size was reduced and the space between the wheels of the landing gear was lowered. A ring radiator incorporated in the nose, while two moderately large air intakes for the radiator on both sides of the fuselage were placed near the cockpit. Clearly Blohm & Voss thought that Bv P205 had potential, reducing the number of radiators and change the engine cooling system could save weight and reduce drag. This new aircraft design was approved and received the designation of BV 155C. There was now a need to build prototypes, the prototypes of V1 to V3 corresponded with the B series aircraft, while V4 to V7 prototypes corresponded with C. The first prototype version Bv 155B was hoped for December 1944. Then later Blohm & Voss and the RLM decided to build only two prototypes BV 155B and then directly go to the series C. In early August 1944 the mock-up was completed and ready for inspection, and this successfully completed construction of the first prototypes was pushed as quickly as possible.
Blohm und Voss P.205 project.
Three views from P.205

P. 205 Illustrative image in flight and the applied cammo.

In September 1944 a revised timetable had Bv 155B V1 ready by December 1944 and the V2 ready to January 1945, while the number of series C preproduction aircraft rose to 30. In October 1944, the BV 155B was reclassified as "escort fighter" this was possibly because at this stage there was a massive reevaluation of all aircraft in production in the German manufacturing indiustry reducing or canceling orders. During this period the V1 and V2 prototypes were nearing completion, with full V1 prototype just before Christmas 1944. After several tests of vibration, the first flight was scheduled for mid-January 1945. At this stage yet it is carrying out work on finalizing the design for the Bv 155C. Meanwhile, the BV 155 V2 was halfway to being completed, while the BV 155 V3 was only 30% full. In early January 1945, meetings were held in an effort to determine how and where the production of the BV 155 could be decentralized. It was proposed that the Focke-WuIf and Dornier were involved. However, both manufacturers strongly committed to their own programs and placed little hope in entering production line until at least March 1945. Finally, on Monday, February 5, 1945, the BV 155 V1, W.Nr . 360051, was delivered to Blohm & Voss flight section.
Three views and drawing as had been the BV 155B - 1 with cammo applied

Meanwhile the Blohm & Voss officials decided to end all further work on the incomplete BV 155 V3 and concentrate all efforts towards the completion of the first prototype of the C series, the BV 155 V4. At the time, it was moment for the maiden flight of the BV 155B V1 which was held on February 8, 1945. This first flight was cut short by coolant leakage, but fortunately the BV 155B landed without further incident. Working against time, the necessary repairs were made and the modifications were completed on February 10, 1945, a second flight was conducted, this time without repeating coolant leaks. However, the test pilot said that the takeoff was difficult due to the muddy conditions of the grass field. This was the result of rainfall in the past two days. It was also noted that the aircraft had a wide distance between the main landing gear (6702mm) which was the main reason for the tendency of the aircraft to make a loop, even during soft landings. There was also a problem with the main gates of the wheel as they do not close properly, there was a potentially serious problem as it could block the flow of air through the radiators mounted on the wing. Low clouds also prevented the high speeds that were planned for this flight were developed, only a top speed of 218 mph was reached while landing approach speed was modest: 106 mph. After the second test flight, the BV 155 V1 returned to the hangar 2 where he underwent additional work to correct the problems. In the next two weeks plans were made to conduct flight tests with special measuring equipment carried on board and operated by the pilot. It was scheduled to fit a semiautomatic camera to record certain flight conditions. A total of forty tables have been provided with what is expected that much additional flight information could be recorded. Then, on February 20, 1945, a secret directive from OKL based in Berlin came to the Blohm & Voss P212 warning that the BV 155 and BV had been included in the current emergency program. February 21, 1945, was a busy day for the engineered Flight of Blohm & Voss as they rushed to complete vibration test system lubricants motor BV 155 V1 in anticipation of the upcoming tests of flight. This was on 26 February 1945. With the gross weight of 5900kg apparatus in the third off the BV 155 V1 was flawless, despite the very soft condition of the field. The pilot had no difficulty keeping the aircraft on course meanwhile accelerated and left the track. As in the two previous flights, the short take-off was impressive. After taking off again there were problems with the doors of the main landing gear as they do not close properly, possibly in the third attempt the doors are completely closed but in the process there was additional damage to these doors.

Fortunately, refrigeration temperatures remained constant between 225 and 230 degrees F (107 ~ 110 ° C), which were within the permissible limits. This third test flight was relatively smooth, but post-flight inspection revealed that there had been another leak of liquid in the drain tank, a crack in the wing near the wing welding and the landing gear doors. With the arrival of March 1945, Blohm & Voss staff was busy making repairs and modifications to the BV 155 V1 while moving toward the conclusion of the BV 155 V2. In Blohm & Voss on March 7, 1945, it was decided that the BV 155 V1 would have at least 10 hours of flight in March and 15 hours in April, with the most flights carried out to astonishing height ranging from 45,933 and 52,493 feet (14-16 km). It was also envisaged that the BV 155 V2, W.Nr. 360052, is finished and ready to fly in March, with a maximum of 10 hours of flights scheduled test to April 1945. In the coming months work will be continued in the second prototype, while performing repairs and minor modifications in the first prototype. With so many unresolved problems associated with the fourth prototype, the first machine of the C series, there was little progress toward building and only a few elements were built. No other survivors record test flights carried out with the first prototype before the arrival of the British. It is very doubtful to be made some more. On May 3, 1945, the city of Hamburg surrendered to the British.

BV 155 C three views with camo and incorporated badges
Cutaway of a BV 155 C-0
Profile of a BV 155 C-0

All the German staff was ordered to leave Blohm & Voss facilities without exception. Throughout the month of May no German was not allowed into the forbidden zone. British authorities were very interested in the aircraft and the facilities found in Blohm & Voss plant. The British lost no time in declaring things were going to be sent to Britain for examination. Opening doors to Hangar 2 they were found with the BV 155 V1 and immediately made plans to transfer the prototype to England. In Hangar 1 who he discovered the still incomplete BV 155 V2, while the BV 155 V3 prototype was quickly located outside Hangar 1.
Scale mockup of the unique wood build prototype BV 155C-0 (partly)
Determining what happened to the three prototypes BV 155, once fell into British hands is very complex and has led to much confusion. It seems that the BV 155BV1 was airworthy when captured. He was tested by the British after applying logos and serial number PN820? Apparently, the British pilot experienced flight failure forced him to make an emergency landing. In the forced landing the prototype was damaged and the decommissioning. The exact nature of the accident remains unknown. But in any case, the British were deprived of the only example of the BV 155B airworthy. British then quickly collected all components of the BV 155 V2 incomplete and were sent Royal Aircraft Establishment (RAE) in Farmborough, to be displayed during the exhibition of German planes captured conducted in late October and running until November 9, 1945.
One of the few pictures of BV 155 B only survivor in Silverhill in 1973 (USA).

The second armed but still incomplete prototype was put on display for the public inside the building "A". The incomplete third prototype, which meanwhile was also sent to RAE Farmborough, was transferred to MU No. 47, where he was prepared to be sent to the United States. It was thought to complete the second prototype and test it but like other projects at the end of the war were canceled due to lack of budget. Later the third prototype sailed to the United States where he was given the designation FE-505. It was then stored at Wright Field's Air Technical Services Command for several years. It gives then the T2-505 code and stores it indefinitely in the National Air and Space Museum's Paul E. Garber in the Installation Restoration in Silver Hill, Maryland.