GOT: The Blohm & Voss BV 155

[Romantic Technofreak]

Hi friends, welcome to another GOT topic. This time I thought it might be ok just copying the Wikipedia article http://en.wikipedia.org/wiki/Blohm_&_Voss_BV_155 about the BV 155, fill it with pictures and that's it. Closer reading showed this was not sufficient. There is an older article about the Me 155, http://www.geocities.com/Heartland/Village/4082/int_air/bv155-1.htm, I found it more confusing and had chosen Wikipedia instead. But Wikipedia stops near the end, and so it had to take a piece of the Geocities article to fill the gap, although this produces a contradiction about the maiden flight. Inserting the pictures, I found that one picture source distinguishes a Me 155B and a Me 155B1-a, what cannot be found elsewhere. See pictures #3 and #4 and decide yourself. Wikipedia also tells a little mistake about the BV 155C. I took a little chunk from samoloty.ow.pl to correct this.



THE BLOHM & VOSS BV 155


The Blohm & Voss BV 155 was a German high-altitude interceptor aircraft intended to be used by the Luftwaffe against raids by USAAF B-29's. Work started on the design in 1942, but the design went through a protracted development period and was still under construction when World War II ended.


Background
The saga of the BV 155 began at Messerschmitt in the spring of 1942. At that time, it was known under the designation of Me 155, and was a company proposal for a carrier-based single seat fighter. The Me 155 was intended to be based aboard the Graf Zeppelin aircraft carrier, then under construction. In the interest of economy and simplicity, the Me 155 was to use as many Bf 109 components as possible, being basically a navalized version of the earlier Messerschmitt fighter.


The Me 155 was to be powered by a DB 605A-1 liquid-cooled engine of 1475 hp. The fuselage was more-or-less that of the standard Bf 109G, but with an entirely new wing. The undercarriage retracted inwards into wing wells, providing the wider track required for safe carrier landings. Standard naval equipment such as folding wings, catapult spools, and arrester gear were to be fitted. Proposed armament was an engine mounted 20 mm MG 151 cannon and two 20 mm MG 151 cannon and two 13 mm MG 131 machine guns in wings. It had an estimated maximum speed of 403 mph.


Detail design of the Me 155 was complete by Sept 1942. However, the numerous delays in the Graf Zeppelin seemed to indicate that the completion of the carrier would be at least two years away. Messerschmitt was told to shelve the Me 155 project for the indefinite future. Work on the Graf Zeppelin carrier was eventually abandoned.
#1: Me 155 (no subtype letter)
http://img.photobucket.com/albums/v475/Coridano/4ae78b79.jpg


In order that all of that work on the Me 155 project not go entirely to waste, Messerschmitt adapted its design in November 1942 to match a Luftwaffe requirement for a fast single seat bomber. A single 1000 kg SC 1000 bomb was to be carried. All of the carrier equipment and most of the armament was removed from the aircraft. Additional fuel cells were provided and an elongated, non-retractable tailwheel was added to provide ground clearance for the large bomb. The proposal was designated Me 155A.
#2: Me 155A
http://img.photobucket.com/albums/v475/Coridano/a4bfbc6c.jpg


Me 155B
By the end of 1942, the increasing number of USAAF bombing raids and intelligence coming in about the new American B-29 bomber led the Luftwaffe to envisage a pressing need for an effective high-altitude interceptor. Messerschmitt adapted its design to this requirement under the designation Me 155B. The engine was to be the DB 628, which was basically a DB 605A with a two-stage mechanical supercharger with an induction cooler. A pressurized cabin was to be provided. It was estimated that a service ceiling of 46,250 feet could be attained.
#3: Me 155B
http://img.photobucket.com/albums/v475/Coridano/caa1e4a7.jpg


A converted Bf 109G adapted to take the DB 628 engine flew in May 1942 and attained an altitude of 50,850 ft. However, the Technische Amt concluded that a DB 603A engine with an exhaust-driven turbosupercharger was more promising. The DB 603A provided 1610 hp for takeoff and 1450 hp at 49,210 ft. This engine change required that the fuselage be elongated in order to house the turbosupercharger aft of the pressure cabin. Exhaust gases were carried to the turbosupercharger via external ducts. Air was drawn in through via a ventral trough aft of the wing. Standard Bf 109G wings were to be fitted outboard of a new, long-span, untapered wing center section. Other parts were scavenged from existing Messerschmitt designs – the vertical tail was from the Me 209, and the horizontal tail and the undercarriage were taken from the Bf 109G.
#4: Me 155 B1-a
http://img.photobucket.com/albums/v475/Coridano/ec2f56a4.jpg

[Romantic Technofreak]

In August 1943, the Technische Amt decided that Messerschmitt was over-committed, and they decided to transfer the work on the design to Blohm & Voss. After some initial study, the Blohm & Voss design team deemed that the existing Messerschmitt design had too many weaknesses. Several months of argument and finger-pointing between the Messerschmitt transition team and the Blohm & Voss designers followed. Friction between the two teams got steadily worse. In the event, no meeting of the minds was possible, and the Technische Amt eventually decided to throw Messerschmitt off the project entirely, and turn it entirely over to Blohm & Voss.


BV 155A
In September 1943 an order for five prototypes was placed. Blohm & Voss decided that the design problems still needed fixing, but by late 1943 they still hadn't been addressed. A meeting was called to finally address these problems, but the Messerschmitt people didn't bother to show up. As late as November 1943 changes were still being made, and Blohm & Voss decided to remove the complex underwing radiators favoured by Messerschmitt for two large scoop-type units mounted above the wings. B&V built a mock-up and had it tested in the LFA wind tunnel, but Messerschmitt refused to help. Late in 1943 Blohm & Voss formally advised the RLM of their problems with Messerschmitt and implored them to intervene. By this point the T-Amt was just as fed up, and removed Messerschmitt from the project entirely.


The design, now named the BV 155A, was finally completely in the hands of one design team. B&V modified the design with a completely new laminar flow wing in place of the original "extended" one from the Me 155. They also changed details of many other parts of the plane, including new landing gear (from the Ju 87) and a new tail unit.
#5: BV 155A
http://img.photobucket.com/albums/v475/Coridano/74aa3940.jpg



Further wind tunnel testing showed that there was a serious problem with the overwing radiators, at high angles of attack the wing "blanked" them from the airflow and cooling would suffer. The decision was made to abandon the A model completely and move on.


BV 155B
The Blohm & Voss team elected to adopt a laminar-flow airfoil section, and abandoned the idea of using standard Bf 109G wings for the outer panels. The wing center section was redesigned. Two large radiators were mounted over the wing trailing edges at the extremities of the center section. Ju 87 D-6 undercarriage legs and wheels used instead of the Bf 109G units. The Bf 109G horizontal tail surfaces were replaced with larger area freshly-designed units, and the vertical tail surface was increased in size.


The first prototype was designated BV 155 V1, and flew for the first time Sept 1, 1944. Tests with the V1 showed that the outboard radiators were not sufficiently effective in providing cooling, especially at high angles of attack. The intakes on the next prototype were enlarged and underslung beneath the wing rather than placed over it. However, the enlarged radiators caused a CoG problem, which required moving the pressurized cockpit forward. The Blohm & Voss team took this opportunity to replace the original Bf 109G canopy with an aft-sliding all-round vision canopy, and the rear fuselage decking was cut down. This in turn required that a larger rudder be fitted. The ventral radiator bath was also enlarged.


All these changes were incorporated into the BV 155 V2, which flew for the first time on February 8, 1945. which was the first genuine B series aircraft.
#6: BV 155B
http://img.photobucket.com/albums/v475/Coridano/46caa31f.jpg


Let me interrupt here for picture comments. The following two pictures are very easily to google out and show a BV 155B while being worked upon. Not so the third one, I was very surprised to find a picture that shows the BV 155 flying. It might be a fake as well. All three show the airctaft equipped with the aft-sliding canopy, while the section above says the V1 first flew with a canopy in the original Bf 109G configuration. On the third picture, the radiators seem to be smaller and more angular than they use to look. If the picture is genuine, it might show the V1 in an intermediate state. The quoted website, www.messerschmitt-bf109.de (http://www.messerschmitt-bf109.de), shows no hint on it.
#9:
http://img.photobucket.com/albums/v475/Coridano/4a55c5ac.jpg


#10:
http://img.photobucket.com/albums/v475/Coridano/a48dfaf6.jpg

[Romantic Technofreak]

#11:
http://img.photobucket.com/albums/v475/Coridano/533a1558.jpg


The Blohm & Voss team was still not satisfied with the design, and before the V2 began its flight trials they proposed that the engine be switched to the DB 603U having the larger mechanically-driven supercharger of the DB 603E. The DB 603U promised a power of 1660 hp for takeoff and 1430 hp at 49,000 feet. The ventral turbosupercharger was retained. The Technische Amt decided to accept this proposal, and abandoned all work on the BV 155B in favor of the revised design, which was designated BV 155C.


Projekt 205
While all of this was going on, Blohm & Voss designers had been working on additional changes under Projekt 205. P.205 replaced the underwing radiators with an annular one around the front of the engine, a design feature commonly found on a number of German designs. With the wings now free of clutter, they were considerably simpler and were reduced in span. This also had the side effect of reducing the track, which would later prove to be a welcome change. The new design would be simpler, lighter and faster, and plans were made to make it the standard version of the aircraft.
#8: BV P.205:
http://img.photobucket.com/albums/v475/Coridano/9a143e0d.jpg


During the October re-evaluation, it was agreed that V1 through V3 would be completed as B models, while a new series of five would be completed to the new standard as the BV 155C.


BV 155C
The BV 155C was quite different in appearance from the BV 155B. The clumsy wing-mounted radiators of the BV 155B were eliminated, and the main landing gear leg attachment points were moved inboard to retract inwards. The cooling was provided by an annular frontal radiator a la Ta 152. Large circular intakes were attached to the fuselage sides above the wing roots.


At this point, we have to leave Wikipedia for a moment. What was told before, the C-series being equipped with the "annular frontal radiator a la Ta 152", cannot be confirmed by the pictures of it roaming around in the net. See the following one, from samoloty.ow.pl:
#9: BV 155C
http://img.photobucket.com/albums/v475/Coridano/00dcf2ad.jpg


Samoloty.ow.pl comments (translation using poltran.com):
"It is necessary to ascertain that objectively, this subtype simply looks ugly. Inflow of air has been placed under the front part of the hull into an enormous integrated radiator and for simultaneously driving the supercharger. It was possible to clean the aerodynamic profile of the wings due to it and a little to decrease their sweep. Machine has lost on appearance, but it has gained on controllability. The change in construction of the undercarriage considerably reduced the basing area. Wings were entirely new also, as well as a number of sub-assemblies inside the airframe. It referred to the precursor only by the name BV 155C. In essence, it already was a new aircraft."
Samoloty.ow.pl states, a full-dimension dummy of the V4 prototype was finished by 80% at the end of 1944.


In the meantime, the BV 155 V2 was damaged beyond repair during a bad landing. It was to be replaced in the test program by the BV 155 V3. The BV 155 V3 differed from the V2 in having the DB 603U intended for the BV 155C. However, the engine cowling and turbosupercharger were unchanged.


Various armament schemes for the BV 155B were proposed. One proposal had an engine-mounted (or Motorkanone) 30-mm MK 108 cannon and two 20 mm MG 151/20 cannon. Another had a Motorkanone-mount MK 103 cannon and two wing-mounted 20 mm MG 151 cannon. Estimated maximum speed was 404 mph at 39,370 feet and 429 mph at 52,490 feet. Service ceiling was to be 55,610 feet. Empty weight was 10,734 lb. Normal loaded weight ranged from 11,300 to 12,100 lb, depending on the armament provided.


At this point, the Wikipedia article is nearly finished and moves to put a light on the surviving leftovers of the BV 155. As I stated at the beginning, I did not choose the other article for the initial section because Wikipedia seems more clear to me. But the events between late 1944 and the capturing of the remaining prototypes by the British are not mentioned at all in Wikipedia. So, let's take the other article here, and accept that there is a contradiction to the Wikiedia text, that states the first flight of the BV 155 already happened on September 1, 1944., while for the Geocities text on the end of 1944 the BV 155 prototypes are still unflown.


Flight tests

During this period the V1 & V2 prototypes were nearing completion , with the V1 prototype being completed just prior to Christmas 1944. After various vibration tests, the first flight was set for mid January 1945. At about this stage work was still being done on finalising the layout for the Bv 155C meanwhile the BV 155 V2 was about half finished, while the BV 155 V3 was only 30 percent complete. Early in January 1945, meetings were held in an effort to determine how and where production of the BV 155 could be decentralised . It was proposed that the Focke-WuIf and Dornier firms should become involved. However, both of these manufacturers were already heavily committed with their own programs and little hope was placed on either coming on line until at least March 1945. Finally on Monday, February 5, 1945, the BV 155 V1, W.Nr. 360051, was handed over to the flight section at Blohm & Voss.


Meanwhile, Blohm & Voss officials decided to halt all further work on the incomplete BV 155 V3, and to concentrate all efforts toward completion of the first C-series prototype, the BV 155 V4. Meanwhile it was time for the maiden flight of the Bv 155B V1 the date was February 8 1945. This first flight was cut short by leaking coolant, but luckily the Bv 155B landed without further incident. Working around the clock, the necessary repairs and modifications were completed and on February 10, 1945, a second flight was carried out, this time without a repeat of earlier coolant leaks. However, the test pilot noted the take-off was difficult due to the soft, muddy conditions of the grass field. This was the result of rain over the previous two days. It was also noted that aircraft's exceptionally wide undercarriage track (21 ft 11 in 6702 mm) was the chief reason for the aircraft's tendency to ground-loop, even during perfectly soft landings. There was also a problem with the main wheel doors not closing properly, this was a potentially serious problem as it could obstruct the air flow through the wing mounted radiators. Low cloud also prevented any high speeds being attained on this flight, only being able to attain a max speed of 218 mph landing approach speed was a modest 106 mph. After the second test flight, the BV 155 V1 was rolled back in hangar 2 where additional work was carried out to correct the problems. In the next two weeks plans were made to carry out tests using special flight measuring equipment to be carried onboard and operated by the pilot. It was planned to fit a semi-automatic camera to record certain flight conditions. A total of forty frames were planned with which it was hoped that much additional flight information could be recorded.

Then on February 20, 1945, a secret directive from OKL headquarters in Berlin to Blohm & Voss was received advising them that the BV P212 and BV 155 had been included in the current Emergency Program. Thursday, February 21,1945, was a busy one for the Flight Mechanics Section at Blohm & Voss as they rushed to complete vibration tests with the BV 155 V1's engine lubricating system in anticipation of the next test flight. This was to be on Monday, February 26, 1945. With the aircraft's gross weight now at 13,007 lbs (5,900 kg), the Bv 155 V1's third take-off was flawless, despite the very soft condition of the field. The pilot had no trouble keeping the aircraft on its course as he sped across the field and left the ground. As in the two previous flights, the short take-off run was impressive. After take off there was more trouble with the main gear doors not closing properly, eventually on the third attempt the gear was fully stowed, but in the process additional damage had been done to the wheel doors.


Fortunately, coolant temperatures remained constant between 225 and 230 degrees F (107~110 Deg C), which were within permissible limits. This third test flight was relatively uneventful but upon Postflight inspection, it was revealed that there had been another fluid leak in the drain tank, and a crack in the wing spar near the aileron lever weld & the main gear doors. With the arrival of March 1945, Blohm & Voss busied itself with making repairs and modifications to the BV 155 V1 while pushing ahead toward completion of the BV 155 V2. At Blohm & Voss on March 7, 1945, it was decided that the BV 155 V1 would log at least 10 flight hours in March and 15 hours in April, with most flights to be carried out at astonishing altitudes of between 45,933 and 52,493 feet (14-16 km). It was further proposed that the BV 155 V2, W.Nr. 360052, would be finished and flight-cleared in March, with up to 10 hours of test flights scheduled for April 1945. Over the next month work was continued on the second prototype, whilst repairs and minor modifications to the first prototype. With so many unresolved problems associated with the forth prototype, the first machine of the C-series, there was little progress toward construction and only a few items of hardware were built. There is no surviving record of additional test flights carried out with the first prototype prior to the arrival of the British. It is very doubtful any were made.


End of the Geocities article (it terminates with some open questions which are at least partly solved by the Wikipedia article, with which we continue).


Survivors
On May 3, 1945, the city of Hamburg surrendered to the British, who ordered everyone out of the Blohm & Voss plant. BV 155 V1 was found in a flyable state, and the British brought in a pilot to fly it to England for testing. Unfortunately the aircraft encountered problems immediately and crash-landed. All the parts for the still-incomplete V2 and V3 were shipped to Royal Aircraft Establishment at Farnborough, and V2 was put on public display in October.
(Everybody may ignore the He 162's empennage to the left, everybody but Corsarius may ignore the Me 163 in front, and all may concentrate on the BV 155B in the rear section):
#12: BV 155 V2 and other German aircraft on display at Farnborough:
http://img.photobucket.com/albums/v475/Coridano/775684fb.jpg

[Romantic Technofreak]

There was some discussion of completing the aircraft using parts of V3, but it was believed this did not take place, and one of the aircraft was later handed over to the U.S. The aircraft was evaluated at Wright Field near Dayton, Ohio, and was given the foreign equipment number FE-505. This aircraft was eventually transferred to the National Air and Space Museum's storage facility in Suitland, Maryland. For years it was believed that this aircraft was the incomplete V3 aircraft, and that the British had retained V2 for their own display, though no record of the aircraft's fate could be found. In 1998 restoration efforts by two of the NASM staff revealed that the sole surviving aircraft is in fact V2, with some of V3's parts applied to the airframe. It is now believed that the British attempted to restore V2 by combining both aircraft prior to donating it to the U.S. This also explains why no record of V3 exists after the U.S. received the aircraft.


End of Wikipedia text. There are pictures of the stored aircraft to be found on the net, the second one gives an impression of a rather big aircraft.
#13:
http://img.photobucket.com/albums/v475/Coridano/a16f58e0.jpg


#14:
http://img.photobucket.com/albums/v475/Coridano/37dfa1ec.jpg



To finish, I like to show you some model pictures from the net. #15 shows a nice Me 155 model, #16 and 17 show the B-subtype, #18 shows a C-version, that, in my eyes, is at least not THAT ugly (pipes and camera position make it look a bit more slim...).
#15: Me 155B:
http://img.photobucket.com/albums/v475/Coridano/eaa4ea03.jpg

#16: BV 155B:
http://img.photobucket.com/albums/v475/Coridano/303c4d57.jpg

[Romantic Technofreak]

First time here? Scroll up please!

#17: BV 155B:
http://img.photobucket.com/albums/v475/Coridano/20c0676f.jpg


#18: BV 155C:
http://img.photobucket.com/albums/v475/Coridano/f7c34526.jpg


All pictures were improved using XnView, if necessary.


Picture sources:
#1, 2, 3, 4: xs4all.nl/~tozu/me109/family/me155.htm
#8: xs4all.nl/~tozu/me109/family/bv155.htm
#12: xs4all.nl/%7Erobdebie/me163/191912.htm
#5: samoloty.ow.pl
#6, 7, 9, 10, 11, 14: zonamilitar.com.ar/foros/showthread.php?t=16649
#13: aircraftresourcecenter.com/AWA1/201-300/walk235_Blohm_und_Voss_Bv-155/walk235.htm
#15: modelingmadness.com/reviews/axis/luft/wantame155.htm
#16: ipms-mardelplata.com.ar/galeria.htm
#17: hsfeatures.com/features04/bv155am_2.htm
#18: modelingmadness.com/reviews/axis/luft/wanta155c.htm



Hope you enjoyed, and best regards, RT

[Wuzak]

Such a lot of work for no result.....