|The Heinkel He 115 is oft-regarded as one of the best seaplanes to have served in World War 2 on any side.|
By all accounts, the He 115 series of floatplane aircraft was regarded as the finest such aircraft in all of World War 2. She served in a variety of offensive- and defensive- minded roles, attacking enemy shipping whenever possible and making life in waterways a living hell. She also served well in the mine-laying role and consistently fed the North Sea a healthy dose of anti-ship mines for some duration. Beyond her operations with Germany, the countries of Bulgaria, Finland, Norway and Sweden all utilized this fine machine at one point or another. Additionally, the United Kingdom and their Royal Air Force made use of at least four requisitioned Norwegian He 115s in several clandestine operations to follow. Some 500 production examples were reported to have existed.
The He 115 received its origins in a 1935 Reich Air Ministry requirement calling for a twin-engine floatplane design to handle a variety of military maritime roles - this included that of torpedo bomber, mine layer and reconnaissance platform. Maritime aircraft design dictated certain requirements all its own, predominantly in operational range and in structural integrity. As these aircraft would most likely operate far from their launch points and against the adverse conditions of the sea, this new design would have to be something of a success in almost all areas of her airframe. While the torpedo role was slated as her primary function, the mine-laying and reconnaissance roles would serve as her secondary roles.
In response, Hamburger Flugzeugbau (then a subsidiary of Blohm & Voss, makers of many successful civilian and military floatplanes and flying boats of the time) produced the Ha 140 while Heinkel put forth their He 115. Both designs showed promise and both were selected for prototype construction. Five total prototypes would make up the He 115 development while three would become of the Ha 140. The He 115 proved the more successful approach and resources were allocated to the Heinkel program, leaving the Ha 140 to the history books.
The initial prototype -He 115 V1 - took to the air in August of 1937, setting no fewer than eight international payload and speed records for an aircraft of this type through a series of test flights. The similar He 115 V2 followed in November of 1937. In March of 1938, the He 115 V3 was unveiled with a glassed cockpit - a design facet to become standard in all further He 115 designs. The He 115 V4 came online in May of 1938 and selected as the production form of the He 115 line. This prototype also made use of struts to replace the former's wires that were connecting the floats to the aircraft's fuselage. A further prototype, the He 115 V5, made its debut sometime in 1939. By comparison, the arrival of the He 115 was far better than anything the Allies could field at the time in the floatplane category. She was a technologically advanced design to say the least.
Design of the Heinkel He 115 was characterized by its identifiable floats affixed to the underside of each engine nacelle. The floats ran about the full length of the airframe, positioned along the forward half of the aircraft and connected to the fuselage by way of large thick struts. The fuselage was somewhat tubular in overall shape and noted for a highly-glazed portion encompassing the nose assembly and crew cabin. This windowed approached allowed for stellar visibility from nearly all angles within the aircraft and, with a three-man crew, much could be seen and discerned from the He 115's lofty position. The crewmember in the nose compartment held a position well below the other two crewmembers in terms of elevation. These two crew took their positions in a tandem, back-to-back seating arrangement in the elongated crew cabin, their elevated position offering up excellent vision as well. The fuselage tapered off into a long, though overly conventional, empennage sporting a single vertical tail fin with a clipped tip. The vertical tail fin base supported the applicable horizontal tail planes, each of wide spanning design. Wings were mid-to-low mounted monoplanes with slight dihedral, sporting a noticeably swept leading edge and a lesser so trailing edge. Each wingtip was curved providing for an elegant design. As the He 115 sat well above the waterline, crew access ladders were appended to the fuselage sides, at about amidships, and connected to the airframe from the rear of each pontoon. Engines were held in open-front nacelles and streamlined, tapering off into each wing element just before the flap components along the trailing edges and each powering three-bladed propellers.
The heart and soul of a torpedo bombing floatplane was naturally her armament provisions. While she was given a few choices in terms of armament - 7.92mm MG 15 and MG 17 series machine guns - for self-defense, her "bread-and-butter" was her anti-ship capabilities. This was addressed by the carrying of a single LTF 5 or LTF 6b series torpedo.
In place of this armament, the He 115 crew had access to a pair of SD 500 1,100lb or SC 250 550lb conventional drop bombs. Additionally, the He 115 was cleared for the mine laying role by way of using the LMB III or LMA series mines. After 1943, cannon armament in the form of 20mm MG 151 or 20mm MG FF types were fitted in the lower nose to help suppress ground-based flak guns during torpedo runs.
Production-wise, the He 115 V4 was the face of the He 115 family that began with the He 115A-0. This form was made up of ten pre-production aircraft and armed with a simple single defensive machine gun. It was not until the He 115A-1 added a nose-mounted machine gun did the aircraft gain a respectable defensive armament sphere of protection. The He 115A-1, in turn, produced the export He 115A-2 which were shipped off to Norway and Sweden to complete several pre-war orders. The He 115A-3 sported a revised communications suite and weapons bay.
The He 115B-1 series followed into production and featured an increase to fuel capacity resulting in longer operational ranges. The He 115B series produced three known subvariants designated as R1, R2 and R3. The He 115B-2 was similar in scope but given reinforced floats for hard-surface operations from snow and ice surfaces - essentially designed for Arctic operations.
The He 115C-1 brought about a better defensive armament scheme and resulted in four subvariants known simply as R1, R2, R3 and R4. The He 115C-2 sported reinforced floats as those found on the He 115B-2 production model. He 115C-3 became the dedicated minelayer variant while the He 115C-4 was the dedicated torpedo bomber variant. The He 115D became a "one-off" model that trialed a pair of 1,600 horsepower BMW 801C-series engines - though this model was not selected for mass production. The He 115E-1 was noted as being similar to the He 115C production series and featured still-improved armament capabilities.
In all, the basic form of the He 115 remained largely intact despite her various variants and subvariants. If there were changes of note, they mostly centered around the aircraft's armament or her avionics/communication suites. Other than that, the design proved quite sound, resulting in an abnormally long war time tenure for an aircraft of this classification.
In September of 1939, approximately 60 He 115A and He 115B systems were in operation. with the Kustenfliegergruppen, conducting some limited reconnaissance over the Balkans prior to the German invasion of Poland. At the start of official hostilities, He 115 flight groups were kept busy by way of mine-laying sorties across the North Sea. Flown by the 106th and 406th Coastal Aviation Groups (the latter launching out of northern Norway in 1942), the He 115 was used on these mine-laying runs across the east and southern coasts of England in an attempt to disrupt all merchant shipping and warship maneuvering in the region. The He 115 was called to action during the Battle of Britain and were mainly composed of He 115 A and He 115B series models. Some 33 of the available 60 operational aircraft were lost, mostly due to British coastal flak guns. By the end of the battle, the He 115C models were being placed into service. Hitler eventually halted his much coveted invasion of the British mainland due to mounting losses in the Battle of Britain. Additionally, mounting needs in other areas stopped further production of future He 115 systems for the moment.
The He 115 quickly proved its value against those critical Allied convoy runs across the Arctic shipping lanes. These convoys, delivering badly-needed supplies to the routing Soviet forces, were often fielded without air support and not as well-armed individually as one would hope. These slow-moving convoys provided relatively easy pickings, even for the under-armed and slow-moving He 115 floatplanes. The He 115C-4 production model was primarily responsible for torpedo attacks against these convoys. Regardless, the convoys completed successful runs and the improving war effort led to consistent air-based protection and better defensive armament on the ships themselves, negating the usefulness of the He 115 in this fashion.
By the time of the German invasion of Norway in April of 1940, the Norwegians had already purchased some seven He 115 examples. One was captured by the Germans in the early days of the campaign as paratrooper landings strategically enveloped and cut off key junctions and target points. A few German-owned He 115s were captured themselves by the Norwegians and promptly placed back into service against their former masters. Norwegian-crewed He 115s would serve in this fashion until the end of the German campaign, this completing in June of 1940 and resulting in the capitulation of the nation of Norway to the might of the Third Reich. Four of the Norwegian He 115 managed the long trip to England where the Norwegian government has escaped to. A fifth example landed to safety in Finland while a sixth escaping aircraft was lost somewhere over the North Sea attempting the flight out to the English mainland. The remaining He 115s of Norway were captured and placed into service with the Luftwaffe. The four examples that had made it to England were intended to be used in a leaf dropping campaign by the now displaced government. However, such a mission was deemed a failure in its early stages by the British and called off. Instead, these He 115s would serve the Royal Air Force (with Norwegian crews) proudly in clandestine operations across the coast of Norway and against targets reachable from the Mediterranean Sea. All of these remaining He 115s were ultimately lost before the end of the war in separate incidents and actions.
The Swedes operated a dozen He 115s under the designation of "T 2". These served the country well up until 1952. During the war, the He 115s were kept on standby and protected Swedish waterway interests in the region, ensuring the neutrality of the nation during the conflict and little else. It is of note that five of these twelve were lost to accident.
Production of He 115s began once again in 1943, these being the improved He 115E series models of which 141 were produced.
Despite its inherent floatplane limitations amidst the ever-changing front of sleek fighter planes and more-capable floatplane designs, the He 115 series as a whole would see operation through to the end of the war, no doubt proving the design as anything but excellent. When not dumping torpedoes into the water, or rendering a waterway useless with its mines, the He 115 was an equally adept performer in the maritime reconnaissance role when called upon to do so.
While in direct service with the Luftwaffe, the He 115 was flown largely by Kriegsmarine pilots during her wartime tenure.