Curtiss Model N

The Curtiss Model N was the company’s second successful tractor land plane, and was later developed into the N-9 float plane trainer as well as providing some features for the famous Curtiss JN ‘Jenny’.

Curtiss’s first two attempts at a tractor land plane, the Model G and the Beachey Tractor, were both rather unsuccessful designs. As a result Curtiss decided to hire a British engineer, B. Douglas Thomas, who had been working for Sopwith. He produced two designs, the similar Model J and Model N, which were later merged to form the very successful Model JN, the famous Curtiss Jenny.

Curtiss Model N from the left
Curtiss Model N
from the left

The Model N was built as a two-seat biplane, with the crew sitting in tandem and with equal span level wings. It differed from the Model J in two main ways – first the use of the RAF 6 aerofoil instead of the Eiffel 36, and second in the use of the placement of the ailerons, which were mounted between the wings, instead of on the outer wing panels. Like the Model J, it used the Curtiss shoulder-yoke aileron control system.

The Model N was purchased by the US Army for $7,500 and given the serial number 35. However while it was being tested by the Army Curtiss repossessed it for use in his ongoing legal battle with the Wright Brothers over their patent for controlling aircraft by altering the shape of the wings. Although Wright’s own aircraft has used wing warping, they were also claiming that their patent included ailerons. After taking the aircraft back Curtiss locked the ailerons in place, and rigged the wings to give them seven degrees of dihedral. His aim was to prove that the aircraft could still be flown even without full three axis controls. 

There is some confusion about the later fate of the Model N. It was apparently later modified to carry its ailerons in the upper wing instead of as a separate surface. However at some point it was given a rather more dramatic modification, with the tandem seating replaced with side-by-side seats and the engine replaced by a heavier 90hp British Beardmore engine. Photographs of the aircraft with side-by-side seats still show it with the ailerons between the wings. In this configuration it may have been known as the Model O, although that appears to have been an unofficial name.

N-8

In April 1915 the US Army purchased four Curtiss N-8s for use as observation aircraft, giving them the serial numbers 60-63. These aircraft were similar to the contemporary JN-3, but used the RAF 6 aerofoil of the Model N, a 90hp OX-2 engine, and kept the shoulder-yoke aileron controls that had been replaced on the Jenny. The first of the four was built as a three bay biplane with a wingspan 10ft longer than that of the JN-3, but the other three used the standard wingspan, and the first one was soon modified to that standard. The N-8s were allocated to Pershing’s force during the Mexican Punitive Expedition of 1916, but were never used over Mexico. They were soon turned into training aircraft.

N-9

Curtiss N-9C at Pensacola, November 1916
Curtiss N-9C at Pensacola, November 1916

The N-9 was designed as a float plane, to serve as a primary and advanced seaplane trainer for the Navy. It was given a large central float, with very small floats carried below the lower wing tip. The basic N-9 was powered by a 100hp Curtiss OXX-6 engine, giving it 10hp more than the N-8. The wings were also expanded by 10ft by added 5ft panels between the fuselage and lower wings and extending the upper wing central section by 10ft (similar to the wings of the first N-8). It was also given an extra set of inter-wing struts, making it a three bay biplane. The lower wing had a shorter span and shorter chord than the upper, but the trailing edges were level with each other, so the wings weren’t entirely staggered. It was given the Deperdussin control system, with a wheel replacing the shoulder yoke aileron controls, and a foot bar for the rudder. It isn’t entirely clear, but it would seem likely that it used the RAF 6 aerofoil, thus explaining its place in the N series rather than the JN series.

The standard N-9 was ordered late in 1916, and 205 were built. They were later unofficially known as the N-9C to tell them apart from the N-9H.

The N-9 was followed by the N-9H, which was powered by the 150hp Hispano-Suiza Model A, licence built in the US by Wright-Martin. The standard N-9 could be used as a primary trainer, while the more powerful N-9H was used as a bombing and gunnery trainer. At least 245 of these were built from new. The most obvious difference between the two models was the use of a tall column radiator on the N-9H, which rose above the level of the upper wing. This had to be used because the N-9H had a large propeller spinner which covered the area used by the radiator on the earlier models.

A total of 560 N-9s were built for the Navy during the war, and it remained the Navy’s primary floatplane trainer until 1926. After the war another 50 N-9Hs were built by the Navy using existing spare parts and engines. Curtiss built 100 aircraft, and their subsidiary, the Burgess Co of Marblehead, Mass, built the rest.

The N-9 was the Navy’s primary floatplane trainer until 1926.

Curtiss N-9H A2638
Curtiss N-9H A2638

The US Army also purchased fourteen N-9s early in 1917 to support its own seaplane operations.

N Stats
Engine: Curtiss OXX
Power: 100hp
Crew: 2
Span: 41ft 6in
Length: 27ft 2in
Height:
Empty weight: 1,300lb
Gross weight: 1,800lb
Maximum take-off weight:
Max speed: 82mph
Climb Rate: 4,000ft in 10 min
Service ceiling:
Endurance: 4 hours

N-8 (Standard wing)
Engine: Curtiss OX-2
Power: 90hp
Crew : 2
Span: 43ft
Length: 27ft
Empty weight: 1,335lb
Gross weight: 1,932lb
Maximum speed: 70mph
Endurance: 4.5 hours

N9-H Stats
Engine: Hispano-Suiza 8A V-type engine
Power: 150hp
Crew: 2
Span: 53ft 3in
Length: length 30ft 10in
Height: 10ft 8.5in
Empty weight: 2,150lb
Loaded weight 2,765lb
Maximum take-off weight:
Max speed: 80 mph
Climb Rate: 10min to 4,450ft
Service ceiling: 9,850ft
Endurance: 3 hours
Range: 179 miles

Books on the First World War | Subject Index: First World War

How to cite this article: Rickard, J (30 June 2020), Curtiss Model N, http://www.historyofwar.org/articles/weapons_curtiss_model_N.html

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