J.Herris Friedrichshafen Aircraft of WWI (A Centennial Perspective on Great War Airplanes 21)
The FF10 was another unbuilt design, and next Friedrichshafen aircraft to appear was the FF11, the first Friedrichshafen flying boat. Like the FF9 it was powered by a 135 hp NAG six-cylinder engine, but this was mounted in the hull and drove a pusher propeller via a long drive shaft, enabling the propeller to be raised above the spray thrown up by the hull during take-off and landing. The Oertz yacht works built the hull for the FF11 at Reiherstieg in Hamburg; subsequent Oertz designs benefited from this connection as can be seen by looking at the Oertz flying boat designs.
First flight of the FF11 was in February 1914 and it was tested until the end of May on the Bodensee, then shipped to the SVK on 4 June 1914, receiving Marine Number 41. Like most other pre-war Friedrichshafen aircraft, only one FF11 was built.
Friedrichshafen FF11 Specifications
Engine: 135 hp NAG
Wing: Area 53.0 m2
General: Length 11.15 m
Height 3.35 m
Empty Weight 1,180 kg
Loaded Weight 1,500 kg
Maximum Speed: 90 km/h
Climb: 500 m 15 min
The FF21 was an improved version of the Friedrichshafen FF11 developed by Jaray especially for the 1914 Baltic Seaplane Competition. The 150 hp Benz Bz.III engine was built into the flying boat hull and drove the propeller via an extension shaft and bevel gear to keep the four-blade propeller up out of the spray of the hull during landing and take-off.
The flying boat hull was built by the Oertz yacht works, which had also built the FF11 hull, and was clearly related to a motorboat. Again, like most prewar Friedrichshafen aircraft, only a single FF21 was built.
Friedrichshafen FF21 Specifications
Engine: 150 hp Benz Bz.III
Wing: Span Upper 16.90 m
Span Lower 13.70 m
General: Length 11.50 m
Height 2.90 m
Flight, October 16, 1914.
AIRCRAFT "MADE IN GERMANY"
WHICH MAY BE EMPLOYED AGAINST THE ALLIES.
12. The F.F. Flying Boat
is an experimental machine specially built for the Warnemunde-Scandinavia Race. The hull of this machine takes the form of a short deep boat, which only extends back a short distance behind the trailing edge of the lower plane. The engine - a 150 h.p. Benz - is mounted in the rear portion of the hull, and drives through bevel gearing a four-bladed propeller, mounted approximately half way between the upper and lower main planes. Pilot's and passenger's seats are arranged side by side immediately in front of the leading edge of the lower plane, and a curved deck over the front portion of the boat forms a wind-screen for the occupants. As the boat does not extend sufficiently far back to carry the tail planes, these have been mounted on an outrigger consisting of four tail booms connected with struts and braced in the usual way by cross wiring. Ample water clearance is provided by setting the lower main plane at a pronounced dihedral angle, and as a precaution small floats are fitted to the lower wing tips.