Powerplant: Daimler‑Benz DB 605A‑1, around 1,475 PS
This Me 155A was a straightforward carrier fighter on paper, but the Graf Zeppelin programme stalled and was effectively abandoned.
With the carrier’s future in doubt, the Me 155A lost its purpose and was shelved.
Shift to high altitude: Me 155B and the B‑29 threat
New threat, new role:
In 1942, German intelligence received performance estimates for the American Boeing B‑29 Superfortress, which could cruise at altitudes far beyond the reach of existing Luftwaffe fighters.
The RLM issued requirements for a Spezial Höhenjäger (special high‑altitude fighter) and later an Extremer Höhenjäger (extreme high‑altitude fighter).
Messerschmitt adapted the Me 155 into the Me 155B high-altitude interceptor:
Engine: DB 628 (a DB 605 with two‑stage supercharger) or Jumo 213 in some concepts
Configuration: still heavily based on Bf 109G fuselage with new wings and gear
But Messerschmitt was already overloaded with Bf 109 production, Me 210/410, and other projects.
Progress on the Me 155B was slow, and some work was even pushed to a design office in occupied France, where motivation was understandably limited.
Transfer to Blohm & Voss and reinvention as BV 155
Why Blohm & Voss?
By 1943, the RLM realised the Me 155B was stagnating.
At the same time, Blohm & Voss—better known for seaplanes—had design capacity under Dr. Richard Vogt.
The RLM forced a partnership: Messerschmitt would hand over the high‑altitude project to Blohm & Voss, who would redesign it into a more capable Höhenjäger.
The relationship quickly soured.
Blohm & Voss wanted deep structural changes; Messerschmitt disliked seeing its design so heavily altered.
By early 1944, the cooperation was formally broken, and the aircraft was re‑designated Blohm & Voss BV 155.
From Me 155B to BV 155A/B
Blohm & Voss essentially treated the Me 155B as a starting sketch rather than a near‑finished design.
Over 1943–44, they reworked the aircraft into something quite different:
New fuselage: longer, optimized for high‑altitude operations
New wing: very high aspect ratio for thin air performance
New landing gear: based on Ju 87 components
New systems: pressurized cockpit, complex cooling arrangements
The project went through internal Blohm & Voss design stages often labelled BV 155A and BV 155B, though in practice the prototypes V1–V3 embodied evolving configurations rather than cleanly separated production standards.
Airframe and systems design
Overall configuration
The BV 155 was a single‑engine, single‑seat, low‑wing monoplane with a conventional tailwheel undercarriage.
Despite its Bf 109 ancestry, the final BV 155B looked very different:
Long, slender fuselage with a rearward‑sliding canopy
Very long wingspan (over 20 m in the B‑series) for high‑altitude lift
Large underwing radiators in deep gondolas, visually distinctive
Tailwheel gear with main legs retracting inwards into the wings
The aircraft was designed to operate at altitudes around 15–16 km, where air density is low and aerodynamic efficiency is critical.
Wing and high‑altitude aerodynamics
The BV 155’s wing was one of its defining features:
High aspect ratio: long span, relatively narrow chord to reduce induced drag
Laminar‑flow profile (on the B‑series): intended to minimize drag at high Mach numbers and thin air
Large span flaps and ailerons: to maintain control authority at altitude
This wing was a major departure from the compact Bf 109 wing and was central to the aircraft’s projected ceiling and endurance.
Cooling system and underwing radiators
High‑altitude engines with two‑stage supercharging generate significant heat, and cooling them in thin air is difficult.
The BV 155 used a distinctive solution:
Radiators housed in large underwing pods, slung beneath each wing panel
Ducting carefully shaped to maintain airflow and minimize drag
Exhaust routing along the fuselage sides in external ducts, adding to the unusual appearance
These radiators are one of the easiest visual identifiers of the BV 155B prototypes.
Cockpit and pressurization
To keep the pilot functional at extreme altitudes, the BV 155 incorporated the following:
Pressurized cockpit with sealed canopy and pressure bulkheads
Oxygen system as backup and for climb/transition phases
Heated cockpit and windscreen to combat low temperatures and icing
Pressurisation was still relatively new and complex for fighters, adding technical risk and maintenance demands.
Powerplant and performance
Engine choice
The BV 155B was powered by a Daimler-Benz DB 603U (or closely related high-altitude DB 603 variant) with a two-stage, two-speed supercharger and intercooling, tailored for extreme altitude.
Earlier concepts had considered the DB 628 or Jumo 213, but the DB 603 family offered more displacement and better potential at height.
Estimated performance
Because the prototypes never reached full operational testing, most performance figures are calculated estimates rather than measured data:
Maximum speed: roughly in the 650–700 km/h range at optimum altitude (varies by source and configuration)
Service ceiling: projected around 15,000–16,000 m
Range: extended by large internal fuel capacity (around 1,800 L in some configurations), intended to allow long climbs and patrols at altitude
In reality, the prototypes made only a handful of flights, none approaching their theoretical ceiling, so these numbers remain largely on paper.
Armament and intended combat role
Weapons fit
The BV 155 was designed as a bomber interceptor, optimised to attack high‑flying, relatively slow targets like B‑29s rather than dogfight agile fighters.
Planned armament typically included:
One engine-mounted 30 mm MK 108 cannon firing through the propeller hub
Two 20 mm MG 151/20 cannons in the wings
This heavy armament was well suited to destroying large bombers with a few short bursts.
Tactical concept
The operational concept was the following:
Long climb to interception altitude, using the high‑aspect‑ratio wing and supercharged engine.
Single or limited passes against bomber formations, using high closing speed and heavy cannon fire.
Descent and recovery before fuel and pilot endurance became limiting.
In essence, it was a specialised tool for a very specific threat profile—one that never actually materialised over Germany in the form originally feared.
Variants and prototypes
Messerschmitt phase
Me 155A:
Role: carrier fighter for Graf Zeppelin
Engine: DB 605A
Status: design completed, no prototypes flown; cancelled with carrier programme.
Status: design work only; no true Me 155B prototype was completed before transfer to Blohm & Voss.
Blohm & Voss phase
Blohm & Voss relabelled and reworked the design, leading to the following:
BV 155A:
Transitional concept closer to the Me 155B but with B&V structural changes.
Often more a paper stage than a distinct flying variant.
BV 155B:
The main high-altitude configuration, with long laminar-flow wings, underwing radiators, and a DB 603 high-altitude engine.
Prototypes V1–V3 are usually associated with this series.
Prototypes V1, V2, V3
BV 155 V1:
First prototype; flew in 1944.
It embodied many of the new features but still had teething issues, including cooling and handling problems.
It made only a few test flights and never reached high altitude.
BV 155 V2:
Further refined prototype with improved systems and detail changes.
This is the airframe captured by Allied forces and later shipped to the United States; it survives today (in incomplete, stored condition) in the Smithsonian’s National Air and Space Museum collection.
BV 155 V3:
A third prototype under construction at war’s end, intended to incorporate additional refinements.
It was not completed or flown.
Blohm & Voss BV 155v2
Operational context and fate
Competition and redundancy
By the time the BV 155 was nearing flight status in late 1944–early 1945, the Luftwaffe’s situation had changed:
Focke‑Wulf Ta 152H had already flown and was entering limited service as a high‑altitude fighter, using a more conventional layout and sharing more commonality with existing Fw 190 production.
The feared mass B‑29 raids over Germany never occurred; B‑29s were used primarily in the Pacific and against Japan.
Germany’s industrial base, fuel supplies, and pilot training pipeline were collapsing.
In that environment, a highly specialised, technically demanding interceptor like the BV 155 had little realistic chance of reaching operational status.
End of the program
As the war drew to a close:
Testing remained limited to low‑ and medium‑altitude flights.
Development delays, technical complexity, and shifting priorities meant the BV 155 never progressed beyond the prototype stage.
Allied forces captured the V2 airframe; it was shipped to the United States for evaluation and is now preserved (in storage) by the National Air and Space Museum.
The project was formally terminated with Germany’s defeat in 1945.
Significance and legacy
The BV 155 is a snapshot of late‑war German aviation: ambitious, technically advanced, but out of step with reality.
Technically: it pushed high-altitude piston-engine design with long-span wings, pressurisation, and complex cooling.
Historically: it shows how strategic fears (B‑29 raids) could drive highly specialised projects that were obsolete by the time they were ready.
Narratively: it traces a rare path—from carrier fighter concept (Me 155A) to high‑altitude interceptor (Me 155B) to a heavily re‑engineered Blohm & Voss design (BV 155B)—without ever reaching squadron service.
