The 1914 Model N was a two-seat biplane similar to the Model J, differing in the airfoil and placement of the ailerons, which were mounted between the wings. It was powered by a 90-100 hp Curtiss OX inline engine. Due to legal issues with the Wright brothers over the use of ailerons, the sole Model N was modified by locking the ailerons and increasing dihedral to seven degrees in an effort to prove that aircraft could be flown without ailerons or wing warping. The Curtiss N Army trainer featured tandem “bathtub” cockpits, trailing interplane ailerons, and cost $7,500. One was delivered on 11 December 1914 (AS35) for Army evaluation but was judged very unstable despite added dihedral. A design merger with the Model J led to the famed JN-4 “Jenny.”

Four 1916 N-8 (Model 1D) variant with 41’9″ wing and standard ailerons were built; AS60-AS63.

The first flight of the Model N took place in 1915. The United States Army purchased the aircraft for evaluation, but Curtiss repossessed it due to legal issues with the Wright brothers.

Developed in late 1916, the N-9 (Model 5) enlarged N was the seaplane version of the JN Jenny. To make the conversion, a single large central pontoon was mounted below the fuselage, with a small float fitted under each wingtip. It had a heavier engine than the Jenny to compensate for the extra weight of the floats and an upper wing that was some 10 feet (3 meters) longer than the lower one. Further modifications to the standard Curtiss JN-4 design were required to cope with stability problems that emerged in the N-9. They included lengthening the fuselage, increasing the area of the tail surfaces, and installing stabilizing fins on the top of the upper wing. The N-9 was initially powered by a 100-horsepower Curtiss OXX-6 engine. The U.S. Navy made use of wind tunnel data developed at the Massachusetts Institute of Technology in its redesign the JN-4. The N-9 was the first U.S. Naval aircraft to incorporate wind tunnel data directly into its design.

The one model N built for US Army was later rebuilt as Model O with side-by side seating.

The Curtiss Aeroplane and Motor Company of Garden City, N.Y., received a Navy contract for thirty N-9s in August 1916. Another fourteen were ordered by the U.S. Army, as it was also conducting seaplane operations at that time. The 100-horsepower N-9 was satisfactory for pilot training, but it lacked the performance needed for bombing operations and gunnery training. To meet these requirements, Curtiss replaced the OXX-6 with a 150-horsepower Hispano-Suiza, then being manufactured under license in the United States by the Simplex Division of the Wright-Martin Company, and later by Wright Aeronautical Corporation. This improved model was designated N-9H.

A total of 731 were built; 122 by Curtiss (A60-A65, A85-A90, A96-A125, A201-A234, A294-A301, A342-A373, A2285-A2290), plus 681 subcontracted to Burgess Company of Marblehead, Massachusetts and also seen as Burgess N-9 (A409-A438, A999-A1028, A2351-A2572, A2574-A2650), and 50 by NAS Pensacola (A6528-A6542, A6618-A6632, A6733-A6742, A7091-A7100) from spare components and engines.

Although the consensus in early 1917 among aviators and even the N-9’s manufacturer was that the N-9 could not be looped, the pioneering early United States Marine Corps aviator Francis Thomas Evans, Sr., believed it was possible. On 13 February 1917, he flew an N-9 over the Gulf of Mexico off Pensacola, Florida, and began attempts to loop it. He succeeded on his fourth try, becoming one of the first persons ever to loop a seaplane (first pilot to loop a seaplane was Polish aviator Jan Nagórski on 17 September 1916 in Grigorovich M-9 flying boat). Lacking witnesses, he flew over Naval Air Station Pensacola and repeated the feat. In 1936, he received the Distinguished Flying Cross for this achievement. More important, however, were the stall and spin recovery techniques he discovered while flying the N-9 that day. During his first three loop attempts, the N-9 stalled before he reached the apex of the loop and fell into a spin. He found that by releasing back-pressure on the stick and aggressively applying opposite rudder to the direction of the spin he could change the spin into a normal dive and recover, something previously thought impossible in an N-9.

During the war, 2,500 Navy pilots were trained on the N-9. In addition to training a generation of Navy pilots, the N-9 was used to develop tactics for ship-borne aircraft operations in 1916 and 1917, using catapults mounted on armored cruisers. After the war, the N-9 was again employed to successfully demonstrate a compressed air turntable catapult. This type of catapult was later installed on battleships, replacing turret-mounted platforms for launching aircraft. In July 1917, several N-9s were acquired by the Sperry Gyroscope Company and were used as test vehicles for aerial torpedo experiments conducted for the Navy’s Bureau of Ordnance. The N-9 was withdrawn from the U.S. Navy inventory in 1927 after ten years of service.

The Brazilian Naval Aviation also operated the N-9H.

The Murray-Carnes was an all-steel development of the Curtiss N-9 requested by secretary Daniels of the Navy Department in 1918 from the J.W. Murray Mfg. Co. of Detroit.

The Hewitt-Sperry Automatic Airplane was a project undertaken during World War I to develop a flying bomb, or pilotless aircraft capable of carrying explosives to its target. Elmer Sperry, succeeded in arousing the US Navy’s interest.

After the US declaration of war on Germany, Sperry began urging the Navy to revisit the idea. The Naval Consulting Board supported him, and formally requested the Secretary of Navy to apportion $50,000 for the work. The government thus included the development of the flying bomb or aerial torpedo in its war preparations. The Senate went so far as to establish two classes for the type weapon, one for wireless control, the other for completely automatic operation. Final approval came on May 17, 1917, and the Navy agreed to provide five (later upped to seven) Curtiss N-9 seaplanes and to purchase six sets of the Sperry automatic control gear. Navy Secretary Josephus Daniels agreed to spend $200,000 on the project, with the money to be administered by the Bureau of Ordnance, the Bureau of Construction and Repair and the Bureau of Engineering. The operation was established at Copiague, Long Island.

In 1913, the Navy provided a flying boat to test and evaluate the gyro-based autopilot. Sperry’s son Lawrence served as an engineer during the test phase. In 1914, Lawrence Sperry was in Europe and observed the developing techniques of aerial warfare, including the use of aircraft. In 1915, the New-York Tribune broke the news of the project. In 1916, the two Sperrys joined Peter Hewitt, an early inventor of radio-related devices, to develop an explosive-laden pilotless airplane.

The system consisted of a gyroscopic stabilizer, a directive gyroscope, an aneroid barometer to regulate height, servo-motors for control of rudders and ailerons, and a device for distance gearing. These all could be installed in an airplane which could be catapulted or flown from the water, and would climb to a predetermined altitude, fly a pre-set course, and after traveling a pre-set distance, drop its bombs or dive to the ground. Wilkinson reported that the weapon did not possess a degree of accuracy sufficient to hit a ship, but, because of its range of 50 to 100 miles (80 to 161 km), it might be of interest to the Army.

The autopilot equipment was already designed, but the radio control system hadn’t been fully developed, so while the hangars were being built at Copiague, Sperry turned his attention to this aspect, purchasing rights to a number of patented radio-related inventions. Ultimately, though, the radio control systems were not used on the Hewitt-Sperry Automatic Airplane. Later, in 1922, the system was installed on several Verville-designed planes along with gear for the Army Air Services engineering division. These aircraft successfully hit their targets from ranges of 30, 60 and 90 miles (140 km).

The first test flights of an autopilot-equipped aircraft was in September, 1917, and took place with a human pilot on board to fly the takeoff. By November, the system successfully flew the aircraft to its intended target at a 30-mile (48 km) range, where the distance-measuring gear would drop a bag of sand. Accuracy was within two miles (3 km) of target.

When the N-9 flight test program got started, it became apparent that a more efficient airframe was needed. Because war production deliveries could not be diverted, a special, rush order was placed with Curtiss in October, 1917, for six planes of unique design, with an empty weight of 500 lb (230 kg), top speed of 90 mph (140 km/h), range of 50 miles (80 km) and the capability of carrying up to 1,000 lb (450 kg) of explosives. They became known as the Curtiss-Sperry Flying Bomb. Because this was to be a design dedicated to the remote control concept, the planes were not equipped with seats or standard pilot controls.

Only one example of the type has survived, and is now a part of the National Air and Space Museum collection. Originally on display at the Museum of Science and Industry in Chicago, Illinois, it was later transferred back to the U.S. Navy pending transport to the National Air and Space Museum. The Naval Air Engineering Laboratory in Philadelphia, Pennsylvania, fully restored it in 1966.

N / N-9C
Original N-9, later known as the N-9C.
Engine: Curtiss OXX-3, 100hp (75 kW)
Wingspan: 38’3″
Length: 27’2″
Speed: 70 mph
Seats: 2

N-8
Production version of N for US Army, Equivalent to JN-3.
Engine: 90 hp (67 kW) Curtiss OX-2
Four built 1915

N-9
Engine: 100hp OXX-6
Wingspan: 53’4″
Length: 30’10”
Useful load: 625 lb
Max speed: 80 mph
Cruise speed: 70 mph
Range: 180 mi
Seats: 2

N9-H
Engine: Wright-Hisso, 150 hp (110 kW)
Propeller: 2-bladed fixed-pitch wooden
Wingspan: 16.2 m (53 ft 4 in)
Wing area: 496 sq ft (46.1 sq.m)
Length: 9.4 m (30 ft 10 in)
Height: 3.3 m (10 ft 9 in)
Weight: Empty weight: 973 kg (2,140 lb)
Gross weight: 1,257 kg (2,765lb)
Useful load: 625 lb
Maximum speed: 78 mph (126 km/h, 68 kn)
Cruise speed: 70 mph
Service ceiling: 6,600 ft (2,000 m)
Time to 3,240 ft (990 m): 10 minutes
Range: 180 mi
Seats: 2

N9-M

N-9N
Engine: 150 hp (112 kW) Wright A

In 1914 Curtiss lured B. Douglas Thomas from Sopwith to design the Model J trainer, which lead to the JN-4.
The JN-4 was developed from the JN-2, via the interim JN-3 which had featured unequal-span wings with ailerons on the upper wing only and introduced a wheel-type aileron control system. Redesigned vertical tail surfaces had a fin and rudder assembly with contours which were to be largely retained in the JN-4. The UK bought 91 JN-3s and the US Army two. Several JN-2s were converted subsequently to JN-3 standard by the incorporation of JN-3 wings and vertical tail surfaces and by installation of the 75kW Curtiss OXX engine. Total production was no more than 100, a dozen built at a newly-built Toronto factory.

Flying the Curtiss JN-4

The JN-4 in its original form closely resembled the JN-3, retaining the same unequal-span two-bay wing and cross-axle landing gear. It first appeared in July 1916 when 105 were sold to the UK and 21 to the US Army. Others were purchased by private owners and a number were operated by the Curtiss company’s flying schools. As a result of British experience with the JN-3 and JN-4 the Curtiss company developed the JN-4A (retro-designated Model 1 in 1935), which incorporated a number of improvements (larger tailplane and engine downthrust). A total of 781 was completed, 87 of them at the Curtiss Canadian factory. The US Army bought 601, the US Navy five and the rest were exported to the UK. The JN-4B (Model 1A) appeared in late 1916, just before the JN-4A. It differed in several design details (it introduced-the larger tailplane and used the OX-2 engine), and found a number of private purchasers and flying schools as customers, added to which the US Army bought 76 and the US Navy nine.
Two examples of the experimental JN-4C were followed by the very successful JN-4 Can and JN-4D (Model 1C). The JN-4 Can had been developed from the JN-3 by the Curtiss company’s Canadian associate, Canadian Aeroplanes Limited, and soon became known as the Canuck. Production totalled 1,260 of which 680 went to the US Army while the bulk of the remainder became the standard Canadian primary trainer. The JN-4 Can served with the Royal Canadian Air Force until 1924, while privately owned aircraft remained in use into the 1930s. John Ericson, chief engineer of Canadian Aeroplanes Ltd, assembled 127 aircraft in 1927, most of them reconditioned aircraft incorporating many parts which had been held in stock. Some had a third cockpit and were known under the designation Ericson Special Three.

The Curtiss JN-4 two-seat biplane soon acquired the nickname ‘Jenny’ which was used widely during the inter-war years. It was one of the most significant American aircraft of its time. From April 1917 when the USA entered World War I it was built in large numbers and used to train some 95% of all American and Canadian pilots. It achieved renewed fame from 1919 until the late 1920s, when thousands were flown in the barnstorming era, thrilling spectators at travelling aerial pageants and shows throughout the United States.

The JN-4D appeared in June 1917 and went into large-scale production, 2,812 being built between November 1917 and January 1919. With an urgent need for efficient trainers in wartime conditions the production involved six other US manufacturers.

The St. Louis Aircraft Corporation became one of six across the country to produce the Curtiss JN 4D Jenny with first deliveries in 1918. The first order was for 200 planes, the company delivered 30 aircraft per month, and 57 JN 4D October 1918. The St. Louis Car went on to manufacture 450 JN-4D Jenny trainers for the U.S. Army.

As well as several new features, the JN-4D combined the more successful elements of both the JN-4 Can and JN-4A designs (stick control of the former, in place of the Deperdussin system, and the lines and engine downthrust of the latter). The end of World War I led to cancellation of contracts for 1,100 examples of a JN-4D-2 version, which had a number of modifications requested by the US Army. In the event, only the prototype was delivered to the military authorities, although several were sold to civil operators in 1919.
In a bid to provide an advanced trainer to meet urgent wartime needs, the JN-4D was re-engined with the more powerful 112kW (150-hp) Hispano-Suiza built by the Wright company. The resulting JN-4H (Model 1E) was in production from the end of 1917 to the November 1918 armistice, 929 being delivered to the US Army. The JN-4H was completed also in dual-control (JN-4HT), combing (JIM-4HB) and gunnery trainer (JN-4HG) versions.
The one-off JN-5H advanced trainer was built to a US Army requirement, but was rejected in favour of the Vought VE-7. It was developed into the JN-6H (Model 1F) which had a strengthened aileron control structure. The US Army purchased 1,035 JN-6Hs, subsequently passing five examples to the US Navy. The aircraft delivered to the US Army were built in sub-variants specialised for various training functions. (JN-6HB single-control bomber trainer, JN-6HG-1 dual-control trainer, JN-6HG-2 single-control gunnery trainer, JN-6HO single-control observation trainer and JN-6HP single-control pursuit [fighter] trainer).
With the armistice the production was stopped, after more than 6000 were produced, mostly of the “D” model.
As part of the post-war economy drive the US Army was forced to modernize the ‘Jenny’ rather than purchase new designs. This task was allocated to US Army Service Depots, which upgraded many of the earlier versions until 1926. The revised aircraft all used Wright-built 134kW Hispano-Suiza engines and were redesignated JNS (standing for JN Standardized). Between 200 and 300 JNS trainers were completed.
The US Army used JN-4As, JN-4Ds and JN-4 Can primary trainers until 1919. The higher powered JN-4Hs and JN-6Hs remained in service until they were phased out in favour of new types in the mid-1920s, the last Jennies being withdrawn from US Army service in 1927.

From 1919 onwards Jennies had been sold to private owners, many who used their aircraft as stunt pilots in travelling circus or barnstorming. The Jenny also featured in many Hollywood films of the 1920s and early 1930s. A considerable number of Jennies survive in museums and several in private ownership are maintained in flying condition in the USA.

Ultralight replica:
Early Bird Aircraft Jenny

Gallery

Curtiss JN-4D
Engine: 1 x 67kW, 90 hp Curtiss OX-5 inline piston
Max take-off weight: 871 kg / 1920 lb
Empty weight: 630 kg / 1389 lb
Wingspan: 13.30 m / 43 ft 8 in
Length: 8.33 m / 27 ft 4 in
Height: 3.01 m / 9 ft 11 in
Wing area: 32.70 sq.m / 351.98 sq ft
Max. speed: 121 km/h / 75 mph
Cruise speed: 97 km/h / 60 mph
Ceiling: 1980 m / 6500 ft
Range 200 miles / 320 km
Seats: 2

JN 4H
Engine: Hispano-Suiza, 150 hp