In a flying boat, the main source of buoyancy is the fuselage, which acts like a ship's hull in the water. Most flying boats have small floats mounted on their wings to keep them stable. All large seaplanes have been flying boats, their great weight supported on their hull.
The first Brandenburg flying-boat was the 3-seat flying boat developed by Ernst Heinkel from a Lohner design and built in small numbers for the German and Austro-Hungarian Navies in 1915. In 1916 Heinkel produced an original design for a single-seat wooden-hulled fighter flying-boat, which he named CC after Camillo Castiglioni, financial controller of the Brandenburg company. The CC was characterized by 'starstrut' interplane bracing like that used for the D.II.
After flight trials with the prototype a single CC was ordered by the German Navy. This was delivered to Warnemunde in February 1917, powered by a 150hp Bz.III engine and armed with a centrally mounted Spandau front gun.
Two CC production batches totaling thirty-five aircraft were delivered during 1917; these had wing radiators and a twin-Spandau armament. Some also had slightly lengthened hulls. Major user of the CC was the Austro-Hungarian Navy, for whom the type was built by Phoenix.Hansa Brandenburg
Designated in the A class in Austrian service, the flying-boats were used up and down the Adnatic in defense of ports and naval bases. Like their German counterparts, they were at first fitted with one. and later with two, machine-guns; it may be supposed that these were the domestic 8mm Schwarzlose weapon.
The Lohner L was a reconnaissance flying boat produced in Austria-Hungary during World War I. It was a two-bay sesquiplane of typical configuration for the flying boats of the day, with its engine mounted pusher-wise on struts in the interplane gap. The pilot and observer sat side-by-side in an open cockpit, and both upper and lower sets of wings featured sweepback. The design was essentially more powerful version of the Lohner E, and proved to be highly influential. Apart from licenced production by UFAG, the L provided the basis for designs from other major manufacturers.
In Germany, Hansa-Brandenburg manufactured a modified version of it as their first flying boat, the FB, and in Italy, a captured example was used as a pattern aircraft by Macchi, who produced it as the L.1. In turn, the L.1 would provide the foundation for a large number of Macchi designs over the coming years.
The captured aircraft (serial L.40) was taken intact near the naval air station of Porto Corsini. The captured flying-boat was copied by Macchi-Nieuport and the L.1 was built within a month. The L.1s were delivered to Italian maritime reconnaissance and bombing units based on the Adriatic. An improved version was developed as the Macchi L.2
The W.18 single-seat fighter flying boat was, like the CC that it supplanted, intended primarily for the Austro- Hungarian Navy. The prototype was flown early in 1917 with a 150hp Benz Bz III six-cylinder water-cooled engine, and production with a 200hp Hiero engine was undertaken on behalf of the Austro-Hungarian Navy, a total of 47 being delivered between September 1917 and May 1918.
Brandenburg W.18: this improved version of the Brandenburg CC had some aerodynamic refinements, of which the most important abandoning the "star" wing struts in favor of more conventional layout. Armament normally comprised two fixed forward-firing 8mm Schwarzlose machine guns
The W.18 was employed for both station defence and fighter patrol tasks. One Benz-engined example was delivered to the German Navy in December 1917.