O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
Friedrichshafen FF 53
Twin-engined torpedo aircraft. Three built: Nos. 1663-1665, June 1917. Power units 260 h.p. Mercedes C IVa.
J.Herris Friedrichshafen Aircraft of WWI (A Centennial Perspective on Great War Airplanes 21)
The final Friedrichshafen torpedo bomber design was the FF53. This was a larger, more powerful aircraft resembling a floatplane derivative of the Friedrichshafen G.IIIa or G.IV land plane bombers. Like the G.IIIa, it was powered by two 260 hp Mercedes D.IVa engines, but unlike the G.IIIa the engines were mounted as tractors to keep the propellers out of the water spray from the floats.
Three aircraft, Marine Numbers 1663-1665, were ordered in June 1917. Photographs verify that at least MN 1663 was completed. Its first flight was on July 30, 1918, and it was handed over to the SVK in August. However, SVK delivery records after the end of June 1918 are not available, so it is not certain the last two aircraft were completed. By this time the Navy had abandoned torpedo bomber operations so the FF53, now intended for long- range maritime reconnaissance, must have had low priority as the Gotha WD.14 was already fulfilling that role. Ironically, the FF53 finally had the more powerful engines needed to carry a heavier torpedo or bomb load compared to previous Friedrichshafen torpedo bombers, but to no avail. Unfortunately, no specifications for the FF53 have survived.
Torpedo planes were built in only small numbers. One reason was the higher priority given to army aircraft, and another was the vulnerability of the bombers to anti-aircraft fire during their torpedo run, when they had to maintain a constant course, speed, and altitude before releasing the torpedo. The torpedo bombers were large, slow aircraft flying at extreme low altitude, making them ideal targets for anti-aircraft gunners aboard ship. As a result, torpedo bombing was abandoned after modest successes and most missions flown by these aircraft were reconnaissance, bombing, and mine laying.
Friedrichshafen Torpedo Bomber Specifications
Specification FF35 FF41a FF41at FF53
Engines 2x160 hp Mercedes D.III 2x150 hp Benz Bz.III 2x150 hp Benz Bz.III 2x260 hp Mercedes D.IVa
Span (Upper), m 23.74 22.00 22.00 -
Span (Lower), m 21.02 20.97 20.97 -
Length, m 13.50 13.70 13.70 -
Height, m 4.50 4.65 4.65 -
Wing Area, m2 100.00 112.50 112.50 -
Empty Wt., kg 2,292 2,300 2,288 -
Loaded Wt., kg 3,543 3,670 3,701 -
Max. Speed, km/h 114 125 121 -
Cruise Speed, km/h - 115 - -
Climb to 500 m - - 9 minutes -
Climb to 800 m - - 16-18 minutes -
Climb to 1,000 m - - 20-25 minutes -
Range, km 770 575 605 -
Crew 3 3 2 3
Armament 726 kg torpedo & 1-2 Parabellum guns 726 kg torpedo & 1 Parabellum gun 726 kg torpedo & 1 Parabellum gun -
Friedrichshafen Torpedo Bomber Production
Type FF35 FF41a Unknown* FF41at FF53
Quantity 1 1 1 8 3
Marine Numbers 300 678 735 996-1000 & 1208-1210 1663-1665
*This aircraft was powered by two 220 hp Benz Bz.IV engines. It was ordered in May 1916 and the order was cancelled on 18 November 1917.