Experimental, WWII

BV 155 – The Enigmatic Aircraft That Pushed Boundaries

The Blohm & Voss BV 155 was a proposed German high-altitude interception and fighter aircraft that could have perhaps altered the course of the war, but its interesting and troubled development history prevented this.

The BV 155 began life as a Messerschmitt concept in 1942 before the design switched hands to Blohm & Voss. The aircraft would go through several design stages and its development was spurred on after German intelligence got word of the Boeing B-29 bomber which at the time could fly higher than any Luftwaffe aircraft was capable of.

Had the BV 155 successfully entered production in time, it could have potentially altered air superiority back towards Germany’s advantage. However several design mishaps and toing and froing by the Nazi government on whether to put the BV 155 into production hampered the plane’s development.

By the time the fighter was potentially ready for production, along with other high-powered interceptions such as the Focke-Wulf Ta 152, the war had turned against Germany to the point of defeat being inevitable.

Blohm & Voss took on the project from Messerschmitt.
Blohm & Voss took on the project from Messerschmitt.

Contents

Origins

The origins of the BV 155 began not as an interceptor plane but with a proposal for a new fighter aircraft sent out by the German Ministry of Aviation in 1942. The specification called for an aircraft that could be launched from aboard an aircraft carrier.

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At the time, the German aircraft carrier Graf Zeppelin was under construction for the Nazi Kriegsmarine and the German military command were looking for aircraft to serve on board the ship, as well as to generally build out their naval air arm fleet.

Messerschmitt took on the proposal and began working on initial drawings for a prototype provisionally named the Me 155.

To save money and get the plane ready for production in time for the carrier’s launch, Messerschmitt took many of the components of their existing Bf 109 fighter and modified it accordingly for use as a carrier borne aircraft. Power would be provided by a Daimler-Benz DB 605 unit. New wings were also added and the undercarriage was designed to retract inwards into the wings.

The DB 605 engine exposed on a BV 155.
As with many of Germany’s aircraft, the 155 was to be powered by a DB 605 engine.

The development schedule on the Me 155 looked promising and by the end of 1942, it was looking set for a maiden flight and completion on time. However, the Graf Zeppelin was labouring behind its proposed launch date and it became clear to Messerschmitt that the vessel would not be ready in time for when their new plane would roll off the production line.

They attempted to sell the Me 155 concept to the Luftwaffe as a high speed strike and fighter-bomber plane, but existing fighter and light bomber aircraft already serving within the Luftwaffe’s arsenal had successfully filled those roles.

The project was initially put on hold by the Messerschmitt engineering team who kept the design drawings but decided not to produce the aircraft unless told to do so in order to focus on getting their existing aircraft out of the factory and into battle.

Changing Circumstances

The fate of the Bv 155 was changed when the United States entered the war in 1941 and declared war on Germany and Japan.

A B-29 in flight above the clouds.
The B-29 could fly higher than any axis aircraft at the time.

At this point, word reached Nazi officials about the American built Boeing B-29 Superfortress bomber. Although the Germans had established air superiority over occupied Europe and the British had found daylight bombing raids over Germany to be a high risk strategy, the Americans believed that day bombing raids should resume and that the B-29 would be the bomber to pull that off.

The B-29 was heavily armed and could cruise higher than other Allied bombers in existence at the time, but crucially no Luftwaffe fighter in service had the capability of climbing to the B-29’s height.

German military officials urged for the resumption of development into a new high speed interception aircraft and Messerschmitt hastily revived the Me 155 project.

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Messerschmitt kept the same basic design but made modifications to the airframe for the plane to perform well at a higher altitude; the engine was swapped to an updated Daimler-Benz DB 605 unit fitted with a double supercharger and the cockpit was pressurized.

The cockpit of the BV 155.
The cockpit was pressurised, meaning high altitude flight was possible.

The Germans had noted that the British had begun to fit the two stage supercharged Rolls Royce Merlin 61 to reconnaissance and high altitude fighter aircraft such as the Spitfire PR Mk.XI and the Mosquito IX, which gave them a superior speed and range compared to most Luftwaffe interceptors.

To test whether the modifications and a two stage supercharger would potentially work, Messerschmitt fitted the modified DB 605 to an existing production model of their Bf 109 fighter and sent it out with a test pilot in May 1942.

The test results found that the new engine would enable the fighter to rapidly climb to an estimated height of around 50,000 feet and possess a range of up to 290 miles, but Messerschmitt concluded that a Daimler-Benz DB 603 fitted with a super turbocharger would perform more effectively.

Although the ideas again seemed promising, Messerschmitt were also finding themselves overwhelmed by keeping up with the constant demands of the German war effort and Nazi officials questioned whether the new fighter would be ready in time.

Messerschmitt agreed to pass the project onto Blohm & Voss in order to focus on producing existing fighters to meet the Luftwaffe’s demands.

The BV-155.
The 155’s design incorporated huge wings, similar to the Ta-152.

Development

Blohm & Voss accepted the project in 1943 on the condition that their engineers would have design freedom and not be locked into what Messerschmitt had already done to the aircraft. The Luftwaffe agreed and ordered five working prototypes for inspection.

The aircraft was accordingly renamed the BV 155. Although the existing design had shown potential under Messerschmitt, the engineering team at Blohm & Voss found certain teething issues and began to radically rework elements of the design, much to the mild annoyance of the Messerschmitt team.

Armament was to be provided by 30 mm cannons and the projected top speed would be 430 miles per hour. Blohm & Voss took the undercarriage from a Junkers Ju 87 Stuka dive bomber and fixed it to their version of the design. All new wings and a redesigned tail fin were also added.

A prototype known as the BV 155 V1 completed its maiden flight in September 1944. The flight uncovered further technical and performance problems, which the Blohm & Voss team tried to rectify with a V2 version of the prototype.

A close up of the engine.
A close up of the engine and cockpit.

The V2 completed its maiden flight on the 8th of February 1945. Although the performance was found to be slightly improved, the Blohm & Voss team still had misgivings about the engine and recommended switching it to a different version of the DB 603. However, the project suffered a setback when the V2 was written off following a forced landing and Blohm & Voss had to work on developing a new working prototype to meet the Luftwaffe’s call.

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Despite appeals from Blohm & Voss, the necessary manpower to build the plane was diverted away to focus on experimental projects at the behest of the Nazi government. But as the Allies stepped up their bombing campaigns from 1944 onwards, the German high command again changed its priorities back to the plane and ordered 30 working examples of the BV 155.

By this stage, it was already strategically too late for Germany to make a difference in the air. The Allies had established almost total air superiority thanks to the deployment of updated variants of Spitfire fighters and new aircraft such as the North American P-51 Mustang which played a substantial role in destroying many Luftwaffe squadrons sent to intercept Allied bombers.

The 155 in a hargar for testing.
The 155 in a hangar for testing.

Spurred on in the face of potential defeat for Germany, Blohm & Voss gamely pressed ahead with the V3 prototype. But the war had turned against Germany to the point of top Nazi officials predicting that defeat to the Allied forces was a matter of time contrary to Hitler’s orders to keep fighting. The Luftwaffe and Nazi high command shifted focus to emergency and easy to fly jet and rocket powered aircraft in a last ditched attempt to claw back lost air superiority and compensate for the depletion in skilled German pilots.

Timing also did not help Blohm & Voss as Focke-Wulf had completed their Ta 152 interceptor designed. The Ta 152 was put into service in January 1945 while Blohm & Voss were still working on correcting issues with the BV 155.

Although the Ta 152 was introduced too late and in too smaller number to have any genuine effect on stopping Allied bombing raids, it was a well-designed interceptor that essentially filled the proposed role for the BV 155. The Ta 152’s existing functional components made the plane easier to be put into production right away.

Blohm & Voss attempted another redesign with the BV 155C which featured improved engine cooling methods and new landing gear, but this version never left the drawing board before the end of the war.

Aftermath

In total, only three units of the BV 155 were completed and the aircraft never progressed beyond the prototype stage.

The design blueprints were handed over to British military intelligence and the V1 was used by the Royal Air Force for testing methods before being written-off. The V2 was shipped to America and donated to the Smithsonian Institute where it remains in storage to this day.

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Although the design teams at Messerschmitt and Blohm & Voss worked to address the problems with the aircraft, the timing and constant change in requirements from the Nazi regime ultimately killed off the plane’s chances.

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Specifications

  • Crew: 1
  • Length: 12 m (39 ft 4 in)
  • Wingspan: 20.5 m (67 ft 3 in)
  • Height: 3 m (9 ft 10 in)
  • Empty weight: 4,870 kg (10,737 lb)
  • Gross weight: 5,520 kg (12,170 lb) Proposal A
  • 5,125 kg (11,299 lb) Proposal B5,100 kg (11,244 lb) Proposal C5,440 kg (11,993 lb) Proposal D
  • Max takeoff weight: 6,020 kg (13,272 lb)
  • Powerplant: 1 × Daimler-Benz DB 603A inverted V-12 liquid-cooled piston engine with TKL 15 turbo-charger, 1,200 kW (1,600 hp) for take-off
  • 1,200 kW (1,609 hp) at 10,000 m (32,808 ft)1,081 kW (1,450 hp) at 15,000 m (49,213 ft)
  • Maximum speed: 420 km/h (260 mph, 230 kn) at sea level
  • Range: 460 km (290 mi, 250 nmi) at maximum continuous power with 595 L (131 imp gal) of fuel at sea level
  • Service ceiling: 16,950 m (55,610 ft) service ceiling
  • Maximum ceiling 17,100 m (56,102 ft)
  • Rate of climb: 11.5 m/s (2,260 ft/min) initial