A floatplane has slender pontoons mounted under the fuselage. Two floats are common, but other configurations are possible. Only the “floats” of a floatplane normally come into contact with water. The fuselage remains above water. Some small land aircraft can be modified to become float planes and in general floatplanes are small aircraft. Floatplanes are limited by their ability to handle wave heights typically greater than 12 inches (0.31 m). These float pontoons add to the empty weight of the airplane, and to the drag coefficient, resulting in reduced payload capacity, slower rate-of-climb and slower cruise speed.

American Floatplanes: 1916

Curtis Model N

Curtiss N-9  - 1916
Curtiss N-9

The Curtiss N-9 was a seaplane variant of the Curtiss JN-4 "Jenny" military trainer used during the First World War. As a seaplane, the N-9 was equipped with a single central pontoon mounted under the fuselage. A small float was fitted under each wingtip. With the additional weight of the pontoon, a number of structural and aerodynamic changes were required, the design of which made use of wind tunnel data developed at the Massachusetts Institute of Technology, meaning the N-9 was the first US Naval aircraft to incorporate wind tunnel data directly into its design. The wingspan was stretched an additional 10 ft, the fuselage was lengthened, the tail surfaces were enlarged, and stabilizing fins were added to the top of the top wing. The N-9 was initially powered by a 100 hp (75 kW) Curtiss OXX-6 engine.

Curtiss was awarded an initial contract for 30 aircraft in August, 1916, and an additional 14 were ordered by the US Army, which maintained a small seaplane operation. It became quickly apparent that the aircraft was underpowered, so Curtiss replaces the engine with a 150 hp (112 kW) Hispano-Suiza, manufactured in the US under license by Wright-Martin’s Simplex division (later Wright Aeronautical). The aircraft was redesignated N-9H.

A total of 560 N-9s were built during the war, most of which were "H" models. Only 100 were actually built by Curtiss. Most were built under license by the Burgess Company of Marblehead, Massachusetts. Fifty others were assembled after the war by the Navy at the Pensacola Naval Air Station from spare components and engines.
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Curtiss Model N-9H
  • National Origin: United States of America
  • Role: Advanced hydroplane trainer
  • Manufacturer:
    • Curtiss Aeroplane and Motor Company
    • Burgess Company
  • Number Built: Aprox. 560
  • Entered Service: late 1916
  • Retired: 1927
  • Operators:
    • United States:
    • United States Army
    • United States Navy
  • Powerplant:
    • N-9C: Curtiss OXX-6 engine 100 hp (75 kW)
    • N-9H: Wright A piston engine 150 hp (112 kW)
    • N-9H: Hispano-Suiza 150 hp (112 kW)
  • Wing Span:
  • Upper: 53 ft., 3 ¾ inches
  • Lower: 43 ft. ⅜ inches
  • Length: 37 ft. 7 ¼ inches
  • Height: 10 ft. 8 ½ inches
  • Net Weight: 2,040 lbs.
  • Gross Weight: 2,550 lbs.
  • Fuel: 179.5 lbs. (29 Gallons)
  • Oil: 37.5 lbs. (5 Gallons)
  • Maximum Speed: 78 mph
  • Stall Speed: 38 mph
  • Climb:
    • 10 minutes To 3285 ft.
    • 14.4 minutes To 5000 ft.
  • Service Ceiling: 7,000 ft.
  • Endurance: 1.7 hrs.


  1. Curtiss Model N. (2009, November 25). In Wikipedia, The Free Encyclopedia. Retrieved 01:45, January 18, 2011, from http://en.wikipedia.org/w/index.php?title=Curtiss_Model_N&oldid;=327911126
  2. The Great War Society Aircraft Of The A E F Curtiss N9. Retrieved 01:45, January 18, 2011, from http://www.worldwar1.com/dbc/curt_n9.htm
  3. Bowers, Peter,Curtiss Aircraft 1904 to 1947
  4. Van Wyen, Adrian O.,Naval Aviation in World War I

Hanriot HD-2

Hanriot HD-2, a U.S. Navy version on floats.

The Hanriot HD.2 was a fighter aircraft produced in France during the First World War. The design was based on that of the HD.1, but the HD.2 was a purpose-built floatplane. It made use of enlarged tail surfaces and shorter wingspans with greater area. Like its predecessor, though, it was a conventional single-bay biplane with staggered wings of unequal span. The prototype had a twin pontoon undercarriage, with a small third pontoon under the tail. The third pontoon was later discarded on production machines, though.

The HD.2 was developed specifically as an interceptor to defend flying boat bases, but soon was used as an escort fighter to protect French reconnaissance flying boats. The United States Navy also bought 10 examples with wheeled undercarriages, designated HD.2C.
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Hanriot HD.2
  • Type: Biplane fighter aircraft
  • Manufacturer: Hanriot
  • Designed by: Pierre Dupont
  • Entered Service: June 1916
  • Variants:
  • HD.2: – floatplane fighter with Clerget 9B engine
    • HD.2C – HD.2: 10 built for USN, plus 2 converted from HD.2 by French Navy
  • H.29 – HD.2: 2 built
  • Wingspan: 25 ft 6 in (8.70 m)
  • Wing Area: 193.7 ft²; (18 m²)
  • Length: 19 ft 2 in (5.85 m)
  • Height: 9 ft 7.5 in (2.94 m)
  • Empty Weight: 895 lb (407 kg)
  • Loaded Weight: 1,331 lb (605 kg)
  • Max Takeoff Weight: 1,437 lb (652 kg)
  • Powerplant: 1× Le Rhône 9J rotary engine, 110 hp (82 kW)
  • Maximum Speed: 114 mph (184 km/h)
  • Range: 342 mi (550 km)
  • Service ceiling: 21,000 ft (6,400 m)
  • Rate of Climb: 5.1 mins to 7,600 ft (2,000 m); 11 mins to 9,840 ft (3,000 m)
  • Crew: one, pilot
  • Armament: 1 × or 2 × Vickers machine gun (7.7 mm)


  1. Hanriot HD.2. (2010, February 13). In Wikipedia, The Free Encyclopedia. Retrieved 06:59, July 31, 2010, from http://en.wikipedia.org/w/index.php?title=Hanriot_HD.2&oldid;=343852844
  2. Taylor, Michael J. H. (1989). "Jane’s Encyclopedia of Aviation". London: Studio Editions. pp. 469.
  3. "World Aircraft Information Files". London: Bright Star Publishing. pp. File 896 Sheet 11.

American Floatplanes1918

Curtiss HA-2

Curtiss Model HA-2 - 1918
Curtiss HA-2 – 1918

The Curtiss HA (sometimes Dunkirk Fighter) was an American biplane seaplane designed by Captain B.L. Smith of the United States Marine Corps, and built by Curtiss Aeroplane and Motor Company.

The HA was a two-seat biplane with a central float and balancing floats on the wingtips. The fuselage was wood with a fabric covering. The plane was powered by a Liberty 12 engine in the nose. The prototype was ordered in December 1917, and its first flight was on 21 March 1918. During testing the aircraft proved very unstable, with an overly heavy tailplane. The aircraft was destroyed in a crash.
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Curtiss HA-2 (BuNo A4111)
  • Role: fighter/mail plane
  • National Origin: United States
  • Manufacturer: Curtiss Aeroplane and Motor Company
  • Designed By: B.L. Smith
  • First Flight: 21 March 1918
  • Number Built: 6 (3 prototypes, 3 landplane mail planes)
  • Powerplant: 1 × Liberty 12, 360 hp ( kW)
  • Wingspan: 42 ft 0 in (12.80 m)
  • Wing Area: 490 ft² (45.52 m²)
  • Length: 30 ft 9 in (9.37 m)
  • Height: 11 ft 5 in (3.47 m)
  • Empty Weight: 2,946 lb (1,336 kg)
  • Gross Weight: 3,907 lb (1,772 kg)
  • Maximum speed: 118 mph (190 km/h)
  • Rate of Climb: 790 ft/min (4 m/s)
  • Crew: 2
  • Armament: 4 × 0.30 in (7.62 mm) machine guns


  1. Curtiss HA. (2010, August 20). In Wikipedia, The Free Encyclopedia. Retrieved 03:54, January 16, 2011, from http://en.wikipedia.org/w/index.php?title=Curtiss_HA&oldid;=380018984
  2. Angelucci, Enzo (1987). The American Fighter from 1917 to the present pp 116-117. New York: Orion Books.