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The Blohm und Voss Bv 155 was a very high altitude fighter which began life as the Messerschmitt Me 155 carrier borne fighter, before changing role and then company, and eventually flying early in 1945 with very long wings, but never flew close to its theoretical high altitudes.
This aircraft was top secret, its design was split between two rival companies, and most variants were either paper designs or incomplete prototypes. It is perhaps not surprising that different sources disagree on the details of each variant. We thus find the first prototype, Bv 155 V1, described as the prototype for the Bv 155A or Bv 155B, and having its radiators either above or below the wings. All wartime photographs of a complete Bv 155 show it with radiators below the wings, and I am thus going to follow Hitchcock’s 1990 Monogram Close-Up work on the Bv 155, which agrees with that detail and appears to be closely based on original documents as well as discussions with Blohm und Voss staff.
In addition the single prototype only made three test flights, and none of these included any high altitude flights, so its potential high altitude performance is based on estimates.
At Messerschmitt
The design of this aircraft evolved from the Bf 109T, a special carrier borne version of the Messerschmitt fighter. A handful of Bf 109T-1s had been built in 1941, but most of the aircraft ordered as the Bf 109T were completed as the T-2, which had the special carrier equipment removed, and were used as standard fighters. Early in 1942 the designers at Messerschmitt began work on an updated carrier fighter, the Bf 109ST (Spezial Tragerflugzeug) or Special Carrier Aircraft. The preliminary design studies were completed by 1 May 1942.
On 20 May 1942 representatives from Messerschmitt and Focke-Wulf met with representatives of the air ministry (RLM) at Messerschmitt’s Augsburg Plant. The RLM wanted two new fighter designs, one for a high altitude fighter (Spezial Hohenjager) and one for a special carrier single-seat fighter (Spezial Trager Jadgeinsitzer), for use on the Graf Zeppelin, the nearest Germany ever came to having an aircraft carrier during the Second World War. Messerschmitt were willing to try both, but warmed that they probably didn’t have the capability to produce these two new designs alongside all of their other work (correctly as it turned out). Focke-Wulf were interested in the high altitude aircraft.
Me 155
Messerschmitt’s existing Bf 109ST was now re-designated as the Me 155. Three variants were proposed – Ausfuhrung A using a DB 605 engine, B using a high altitude DB 628 engine and C using a Junkers Jumo 213. A became the carrier aircraft, as the Me 155A, while B became the high altitude aircraft, as the Me 155B. Both versions used many components from the Bf 109G, in particular the fuselage, but with a new wing and landing gear.
The Me 155A and original Me 155B designed used the fuselage of the Bf 109G, but with a new 36ft 10 5/8in long tapered wing, 35 square feet larger than the Bf 109G wing. A stronger undercarriage would be used.
Me 155A
The Me 155A was originally the carrier version. It would have the new wing and undercarriage and carry naval equipment. Work on the Me 155A was to be carried out at Augsburg.
Early in 1942 work on the Graf Zeppelin was cancelled once again, and with it the Me 155A. It is possible that Messerschmitt attempted to modify the Me 155A into a single seat high speed bomber that could carry a single 2,205lb bomb for use against high value targets, but if so this had no official backing, and nothing came of it.
Me 155B
Work on the Me 155B was soon transferred to a new design team in Paris, led by Messerschmitt but with staff recruited from the French Societe Nationalede Constructions Aeronautiques du Nord (SNCAN). Unsurprisingly work on the project slowed down greatly at this point, partly because the French team had no great reason to work for the Germans and partly because the local Messerschmitt team were working on the Me 309. Things slowed down even further early in 1943 when Messerschmitt decided to focus their high altitude efforts on a version of the Me 209. By the spring of 1943 Messerschmitt were still early in the design process on both the Me 155B and Me 209, while Focke Wulf already had several prototypes in the air! As a result interest in the original Me 155, which was expected to reach 45, 933ft if powered by the DB 628, now ended, and Messerschmitt were asked to try and reach higher altitudes.
Me 155B-1
Work now moved onto the Messerschmitt P 1091, a project that had already been underway at Messerschmitt.. This introduced a new centre section to the wing, increasing the wingspan to 68ft 10 3/4in. This new section was of equal chord, with no dihedral. The wind span undercarriage folded outwards, with the wings stored close to the outer end of the new wing panel. The tapered wings from the original Me 155 design were used as the outer wing panels. A number of different designs of radiators was used, ending with one that had eight radiators carried under the wings. The fuselage was lengthened in order to carry a supercharger behind the cockpit. It would be powered either by the DB 628 high altitude engine, which had a built-in two stage mechanical supercharger or the DB 605 combined with a TK 11 turbo-supercharger. In June 1943 Willi Messerschmitt decided to use P 1091 as the basis of an improved version of the Me 155. This became the Me 155 B-1.
The B-1 used the fuselage from a Bf 109G, lengthened slightly to provide space for the supercharger to be carried behind the cockpit. It had a extra centre section, with straight leading and trailing edges, with the earlier tapered wing sections of the Me 155 at the end. Eight radiators were carried below this new wing section. It had a wide span undercarriage, which retracted outwards, allowing the wheels to sit in thicker wing sections at the end of the new section.
At Blohm & Voss
In August 1943 Walter Blohm, director of Blohm und Voss, and their chief designer Dr Richard Vogt, flew to Berlin for meetings in which the idea of their helping with the Me 155 project was suggested. Dr Vogt was interested in working with Prof Messerschmitt on the design, and after meetings with Messerschmitt’s head of projects an agreement was made. At this point Messerschmitt would still take the lead. Blohm und Voss would provide 120 design engineers along with the staff from their foreign workers office, who would all move to Augsburg for three months. This arrangement was not a success. Messerschmitt appears to have seen Blohm und Voss as a useful source of extra personnel rather than a proper design partner, while the Blohm und Voss team were unimpressed with the work that had already been carried out. Eventually Blohm und Voss complained to the RLM, and early in 1944 control of the project was handed over to them. At this point the Me 155B-1 became the Bv 155A.
Bv 155A-1
After work moved to Blohm und Voss the Me 155B-1 became the Bv 155A-1. However it would appear that this aircraft, which was effectively the Messerschmitt design, was quickly abandoned in favour of the Bv 155B, which introduced a number of changes the Blohm und Voss team had been trying to get agreement while they had been working with Messerschmitt.
Bv 155B
Dr Vogt made a number of changes to the design, although kept the basic layout with the Bf 109G fuselage, supercharger behind the cockpit and very wide wingspan. However the eight radiators below the wings were replaced with two large radiators mounted below the wings, half way out, at the point where the new centre section met the original Bf 109 wings. It kept the wide track undercarriage of the A-1, which retracted outwards so the wheels could be housed in the thickest part of the wings, where the radiators were mounted. At first three B series prototypes were to be built, with the first appearing in December 1944. However on 26 July 1944 the RLM and Blohm und Voss agreed to scrap the B series and move onto the C series. Two prototypes of the B series would be completed.
Bv 155 V1
The Bv 155V was powered by the DB 603U engine, combined with a Heinkel Hirth TKL 15 turbosupercharger. Photographs of a completed Bv 155 all show it with two radiators carried below the wings. Blohm und Voss were finally able to pick up a DB 603 U engine, the third prototype, at the end of September 1944.
The aircraft was completed just before Christmas 1944. Static vibration tests followed, then engine tests on 22 December 1944.
Bv 155 V1 made its maiden flight on 8 February 1945. This would be a short flight, as a coolant leak was discovered in the starboard radiator forcing the test pilot to return to base. A number of problems were discovered even in this first flight – the air speed indicator wasn’t working, the rudder pedals had problems, the canopy jettison cartridge triggered accidentally, the brakes weren’t good enough, there was too much interference on the radio, and the coolant system wasn’t reliable.
V1 made a second flight on 10 February 1945. This lasted longer, but low cloud limited the top speed to 218mph.
The third flight came on 26 February 1945. This time the aircraft reached a higher altitude, although still not approaching the very high altitudes it was designed for. The plan had been to reach either 13,123ft or the cloud base if that was lower, fly at up to 249mph, and test out the aircraft’s performance as a photographic reconnaissance aircraft.
This was the aircraft’s third and final test flight, so it never tested out its high altitude performance.
Bv 155 V2
Bv 155 V2 was the second prototype of B series. It was 30 percent complete by the end of 1944. It was largely similar to the V1.
By May 1945 V2 was about 90% complete when it was captured by the British. The aircraft was taken back to Britain, assembled at Farnborough, and put on public display from late October to 9 November 1945. It then disappeared.
Bv 155 V3
V3 was the third B series prototype. It was 30 percent complete by the end of 1944. However work on V3 was cancelled on 8 February 1945 in order to allow work to focus on the C series prototype V4. This seems very optimistic with the front line now only 200 miles to the west of Hamburg…
After the war this third prototype was taken by the Americans. In the mid 1970s it was photographed in the National Air and Space Museum’s restoration facility in Maryland. The prototype was unfinished, but did have its DB 603U engine.
Bv 155C
Just as Messerschmitt had an alternative in place with their P 1091, Blohm und Voss had their own alternative design, the BV P 205. A number of different engines were suggested for this project, but most of them were yet to be completed, so the same DB 603U and TKL 15 combination as in the Bv 155B was selected. The initial design removed the wing radiators and replaced them with an annular radiator in the nose and radiator air scoops on either side of the fuselage. The wingspan and landing gear width were both reduced. The design was then modified again, removing all the radiators and air scoops and combing them into a single large chin scoop. The very long wings remained, but looking rather more elegant without the bulge of the radiators half way along.
By June 1944 the new design had been approved as the Bv 155C, with four prototypes to be built. On 26 July this changed, when the RLM and Blohm und Voss agreed to cancel the B series and move production onto the C series. Two prototypes of the B series would be completed. Twenty six pre-production Bv 155C-0s were ordered. By September this had been increased to thirty aircraft.
By the end of 1944 a full size wooden mockup had been completed, 75-80% of the technical drawings for components had been completed. Representatives from the Luftwaffe test grounds at Rechlin inspected the mockup and requested a significant number of changes. The firm would still be attempting to make these changes at the end of the war.
Bv 155V4
V4 was to be the first prototype of the C series. It would have the chin radiator scoop, use a 1,810hp DB 603U engine with Hirth TKL 15 supercharger, and have a reduced wing span and undercarriage track. However very little progress was made of V4.
Post-War
On 3 May 1945 the city of Hamburg surrendered to the British 2nd Army without a fight. At 10am on the same day all German staff were ordered out of Blohm und Voss facilities, and everything found there was seized by the British.
V1 was given RAF insignia and serial PN820 (previously used by a Vickers-Armstrong Warwick). The aircraft was taken up for its fourth flight, but suffered an emergency that forced the pilot to land. The aircraft was damaged in the crash and written off.
V2 went to Britain in pieces, and was assembled at Farnborough, where it was displayed in an exhibition of captured German aircraft from late October to 9 November 1945.
V3 also went to Farnborough, before being handed over to the Americans. It left Liverpool by sea on 26 January 1946 and went to Wright Field to be evaluated. However the incomplete Bv 155 was of less interest than more complete designs, and in 1950 it was given to the Smithsonian. It is possible that this aircraft is actually the V2 - the timing would fit, and the Smithsonian aircraft appears to be more complete than might be expected from V3.
Bv 155 V1 (all performance figures are estimates)
Engine: DB 603U
Power: 1,810hp at take-off
Crew: 1
Span: 67ft 3in
Length: 39ft 4.5in
Height:
Empty weight: 10,716lb
Loaded weight: 12,403lb
Max speed: 429mph at 52,480ft
Climb Rate: 29min to 52,480ft
Service ceiling: 55,610ft
Range: 932 miles
Armament: Engine mounted 30mm cannon, wing mounted 20mm cannon
Bomb load:
Aircraft of the Luftwaffe 1935-1945, Jean-Denis G.G. Lepage.
Combines a good background history of the Luftwaffe with a comprehensive examination of its aircraft, from the biplanes of the mid 1930s to the main wartime aircraft and on to the seemingly unending range of experimental designs that wasted so much effort towards the end of the war. A useful general guide that provides an impressively wide range of information on almost every element of the Luftwaffe (Read Full Review)
