The Heinkel He 60 was a German single-engined biplane reconnaissance seaplane designed to be catapulted from Kriegsmarine (German navy) warships of the 1930s. Development and design The Heinkel He 60 was designed by Heinkel engineer Reinhold Mewes, the designer of the He 59. The resulting design was a single-engined biplane of mixed wood and metal construction with fabric covering. Its single bay wings were of equal-span and had significant stagger. The first prototype flew early in 1933 and proved to be underpowered with its 492 kW (660 hp) BMW VI engine. The second prototype had a more powerful version of the BMW engine, but this only marginally improved its performance and was unreliable, so production aircraft reverted to the original engine. Of conventional configuration, the He 60 was a sturdy aircraft, designed (as the specification required) to be capable of operating on the open sea. As a result, it was always somewhat underpowered for its weight, which made handling sluggish and the aircraft vulnerable to enemy fire. Attempts were made to solve its lack of power by fitting one aircraft with a Daimler-Benz DB 600 engine, but engines were not available for production. Operational history Initial deliveries of the He 60 were to Kriegsmarine training units in June 1933. From 1934, the major production version, the He 60C began to be delivered to the shipboard observation seaplane units of the Kriegsmarine, operating from the catapults of all German cruisers. It also saw action with Spanish Nationalist forces during the Civil War. In 1939 it was replaced as a shipboard aircraft first by the He 114 in service, then soon after by the Arado Ar 196, but it remained in service with several coast reconnaissance Staffeln (squadrons) when World War II began. It had been withdrawn from front-line service by 1940, but returned to use following Germany's invasion of the Soviet Union in 1941, being used for coastal patrol work in the Baltic and Mediterranean Seas. All He 60s were removed from service by October 1943. Variants He 60a First prototype which began flight testing in early 1933. He 60b Second prototype which experimented with a more powerful engine. However, it proved no better and the design reverted to that used in the 60a. He 60c Third prototype, used for successful catapult trials in early 1933. This aircraft was delivered into operational service with the navy. He 60A 14 pre-production aircraft