Heinkel He 115 Anti-Ship / Maritime Patrol Floatplane
The Heinkel He 115 is considered by many as the best seaplane to have served in World War 2 on any side.
Authored By Dan Alex; Content ©www.MilitaryFactory.com
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.
He 115 Origins
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.
Heinkel Versus Hamburger
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.
He 115 Walk-Around
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.
Arming the He 115
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.