Throughout 1941 German intelligence had been able to keep a close eye on developments within the US aviation industry through the pages of American magazines and newspapers — which seem to have had no qualms about printing sensitive details that other countries might have worked very hard to keep secret.
As told by Dan Sharp in his book Blohm & Voss BV 155, among many other items, the Auslandsnachrichten des General-Luftzeugmeisters Dienst Nr. 3/41/1 (Reichsluftfahrtministerium, RLM, intelligence briefing on other countries’ aircraft developments) for Sep. 1, 1941, reported on plans to fit the Consolidated B-24D Liberator with a pressure cabin for high-altitude operations, as revealed in Model Airplane News of August 1941. Similarly, an article in Aviation of July 1941, cited in the same document, candidly discussed Boeing’s efforts to design a three-man pressure cabin for operations above an altitude of 12km — the service ceiling of the latest Bf 109 models.
So when America joined the Second World War on the side of Britain and the Allies in December 1941, there was clear concern that the Luftwaffe might soon find itself facing enemy bombers it had no hope of intercepting. These anxieties prompted the RLM to seek a new high-altitude fighter during the spring of 1942. Messerschmitt and Focke-Wulf had already been working to improve the service ceiling of their standard fighters, because a greater peak altitude offers a natural advantage in air-to-air combat, but the RLM wanted them to go further than simply adding a pressure cabin and extended wings to their existing designs.
Focke-Wulf is another story but Messerschmitt focused on tentative work being carried out in with Daimler-Benz on the new DB 628 engine — a DB 605 with a two-stage supercharger for improved performance at high altitude. DB seems to have been doing most of the work, using a Bf 109F airframe under the factory designation ‘Me 409’.
At the same time efforts were being made to correct what was often seen as the Bf 109’s biggest flaw: it’s narrow track undercarriage. New wings with Fw 190-style gear that folded inwards became part of the Me 409 design, as did the revised Bf 109G airframe, and it received the official RLM designation Me 155 (8-155). It was hoped that it could provide the basis for three new aircraft — a standard fighter in parallel to the Me 309, a high-altitude fighter to combat those American bombers and a carrier-based fighter to replace the old Bf 109E-based Bf 109T aboard the Graf Zeppelin.
With Messerschmitt already working at maximum capacity on other projects, the Me 409/Me 155 was given to French subcontractor SNCAN to tackle. But SNCAN seems have had little time for this work and the Me 155 was pushed to the back of the queue.
Messerschmitt itself seems to have been similarly and understandably disinterested in the type. There was some profit in the carrier-based version — or so it seemed until the Graf Zeppelin was cancelled but there was little ongoing interest in a high-altitude interceptor after the initial panic about American bombers had subsided. It was easier to do the same job by re-engining the Bf 109G, providing it with simple rectangular inserts to increase its wingspan and keeping its undercarriage the way it was — as the Bf 109H. Work on all versions of the Me 155 was stopped in early 1943.
When the Me 309 was cancelled and replaced by the Me 209 as the planned successor to the Bf 109, it became necessary to provide a high-altitude option in the form of the Me 209H. A key aspect of Messerschmitt’s (and indeed most other German aircraft manufacturers’) design philosophy by January 1943 was specifying the highest possible proportion of existing components for new types to avoid disrupting supply lines and affecting, production output. The Me 209 was therefore heavily based on the Bf 109G but incorporating a new tail, wings with Me 155-style inwards retracting landing gear and a new engine in the form of the Jumo 213.
The situation changed in May 1943 when the RLM decided that a standard fighter modified to operate at 12km, with a ceiling of around 13km, was insufficient. Both the Bf 109H and Fw 190H (Ta 152H after August 1943) were high-altitude fighters but the RLM needed something able to reach 16km.
During early 1943, the British had started fitting the two-stage supercharged Merlin 61 to their latest reconnaissance machines such as the Spitfire PR Mk.XI and Mosquito IX, putting them out of reach for most German interceptors. And as early as Sep. 1, 1942, a meeting of the RLM’s GL-Besprechung had heard that a Spitfire (presumably a Mk.VI) fitted with a pressure cabin had been recovered from Dieppe following the disastrous Operation Jubilee raid on the French coast on Aug. 19, 1942.
It was clear that quite apart from the Americans having yet to make any real impact on the European theatre, the British too were now developing a worrying high-altitude capability. The RLM therefore requested that Messerschmitt investigate possibilities for a 16km peak altitude machine. The company responded with the three-stage P 1091 project — the first stage of which was the latest iteration of the Bf 109H.
The RLM liked the first and third stages but saw no need for the second and the two surviving projects duly joined the growing queue of projects that Messerschmitt still had no real capacity to work on. The company requested more resources but there were none to be had through conventional channels so Generalfeldmarschall Erhard Milch took the radical steps of scrapping production of Blohm & Voss’s trio of seaplanes — the BV 138, 222 and 238 — and giving that company’s design and production capacity to Messerschmitt. This was arguably a sensible move since the talented team at Blohm & Voss were wasted on continuing to support machines which were largely unnecessary for the Luftwaffe by this point.
Messerschmitt could have chosen to give B&V any of its work — aspects of the Me 262, work on the Me 410, further development of the Me 163, the still-viable Me 209 or even the Me 264 bomber but instead the company handed Blohm & Voss the P 1091 Stage 3. The agreement was signed and the project was given the official designation Me 155B on Sep. 9, 1943 — there never having been an ‘A’. This followed a familiar pattern at Messerschmitt, where the ‘A’ did not exist until there was a `B’. Neither the Me 163 nor the Me 328 existed as an ‘A’ until the Me 163B and Me 328B received those official designations — whereupon the earlier prototypes and projects were retrospectively termed Me 163A and Me 328A.
While the relationship between Messerschmitt and Blohm & Voss started out well enough, the B&V team seem to have had little conception of what a huge operation Messerschmitt AG was nor how little time the company had to babysit them through the early stages of the project. There was a huge falling out, memorably recalled by Hermann Pohlmann in Thomas H. Hitchcock’s Monogram Close-Up 20 Blohm & Voss 155, Monogram 1990, where the Blohm & Voss team were offended and upset because the venue of a meeting was changed at the last minute and they went to the wrong place.
This mix-up resulted in B&V complaining rather petulantly to the RLM, who complained to Messerschmitt, and the two companies’ relationship was soon in tatters. The partnership was broken in February 1944 and the aircraft type received Blohm & Voss’s company initials: BV 155B. B&V struggled to get the manpower needed to build the five BV 155B prototypes ordered because the type’s RLM priority rating was set too low. It did, however, find the time to redesign its radiators, making the prototypes obsolete before they were even built.
As 1944 wore on, the Allies’ bombing of Germany reached fever pitch and stopping the bomber streams became the Luftwaffe’s top priority. This seems to have once again turned the spotlight on the 8-155 and its priority was evidently increased, with an order being placed for 30 examples of the new BV 155C. By now though it was far too late. The first prototype BV 155B made only a handful of flights before crashing with a Luftwaffe pilot at the controls. The second prototype was, of course, captured.
It was an incredible feat for the small and under-resourced Blohm & Voss team to design and build a new and complex fighter in around 18 months — but there is no getting away from the fact that those greatly feared high-altitude American bombers never did appear in the skies over Germany. Had it somehow been rushed into production sooner though, the BV 155 might well have made itself useful in combating the latest high-flying Allied reconnaissance aircraft. The Griffon-engined Spitfire PR Mk.XIX had a ceiling of just over 15km, making it almost completely unassailable from the point at which it reached operational units in May 1944 to the end of the war. With BV 155Cs in Luftwaffe service, the unarmed PR Mk.XIX would have become highly vulnerable.
Blohm & Voss BV 155 is published by Mortons Books and is available to order here along with many other beautiful aviation books. Save 10% on all books with exclusive promotional code ‘AVGEEK10’!
Photo credit: GoodFon.com and Reddit
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