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Canadian Aeroplanes JN-4 Canuck
Single-engine Two-seat Biplane Trainer, Canada


Archive Photos [1]


[Canadian Aeroplanes, Ltd. JN-4 “Canuck” (RFC C227) at the Canada Aviation Museum, Ottawa, Ontario, Canada (Photo by John Shupek)]

JN Series Overview [2]


  • JN-4 “Canuck”
  • Role: Biplane Two-seat Single-engine Trainer
  • Manufacturer: Canadian Aeroplanes, Ltd., Toronto, Ontario, Canada
  • Primary users: RCF in Canada; RAF in Canada; U.S. Army Air Service
  • Number built: 1,260

The Curtiss JN-4 “Jenny” was one of a series of “JN” biplanes built by the Curtiss Aeroplane Company of Hammondsport, New York, later the Curtiss Aeroplane and Motor Company. Although the Curtiss JN series was originally produced as a training aircraft for the U.S. Army, the “Jenny” (the common nickname derived from “JN-4”, with an open-topped four appearing as a Y) continued after World War I as a civil aircraft, as it became the “backbone of American postwar [civil] aviation.” Thousands of surplus Jennys were sold at bargain prices to private owners in the years after the war and became central to the barnstorming era that helped awaken the U.S. to civil aviation through much of the 1920s.

JN Design and Development [2]


Curtiss combined the best features of the model J and model N trainers, built for the Army and Navy, and began producing the JN or “Jenny” series of aircraft in 1915. Curtiss built only a limited number of the JN-1 and JN-2 biplanes. The design was commissioned by Glenn Curtiss from Englishman Benjamin Douglas Thomas, formerly of the Sopwith Aviation Company. The JN-2 was an equal-span biplane with ailerons controlled by a shoulder yoke in the aft cockpit. It was deficient in performance, particularly climbing, because of excessive weight. The improved JN-3 incorporated unequal spans with ailerons only on the upper wings, controlled by a wheel. In addition, a foot bar was added to control the rudder.

The 1st Aero Squadron of the Aviation Section, U.S. Signal Corps received eight JN-2s at San Diego in July 1915. The squadron was transferred to Fort Sill, Oklahoma, in August to work with the Field Artillery School, during which one JN-2 crashed, resulting in a fatality. The pilots of the squadron met with its commander, Capt. Benjamin Foulois, to advise that the JN-2 was unsafe because of low power, shoddy construction, lack of stability, and overly sensitive rudder. Foulois and his executive officer Capt. Thomas D. Milling disagreed, and flights continued until a second JN-2 crashed in early September, resulting in the grounding of the six remaining JN-2s until mid-October. When two new JN-3s were delivered, the grounded aircraft were then upgraded in accordance with the new design. In March 1916, these eight JN-3s were deployed to Mexico for aerial observation during the Pancho Villa Expedition of 1916-1917.

After the successful deployment of the JN-3, Curtiss produced a development, known as the JN-4, with orders from both the US Army and an order in December 1916 from the Royal Flying Corps for a training aircraft to be based in Canada. The Canadian version, the JN-4 (Canadian), also known as the “Canuck”, had some differences from the American version, including a lighter airframe, ailerons on both wings, a bigger and more rounded rudder, and differently shaped wings, stabilizer, and elevators. As many as 12 JN-4 aircraft were fitted with an aftermarket Sikorsky wing by the then fledgling company in the late 1920s.

JN Series Operational History [2]


The Curtiss JN-4 is possibly North America's most famous World War I aircraft. It was widely used during World War I to train beginning pilots, with an estimated 95% of all trainees having flown a JN-4. The U.S. version was called “Jenny”, a derivation from its official designation. It was a twin-seat (student in front of instructor) dual-control biplane. Its tractor propeller and maneuverability made it ideal for initial pilot training with a 90 hp (67 kW) Curtiss OX-5 V8 engine giving a top speed of 75 mph (121 km/h) and a service ceiling of 6,500 ft (2,000 m). The British used the JN-4 (Canadian), along with the Avro 504, for their primary World War I trainer using the Canadian Aeroplanes Ltd. indigenous variant. Many Royal Flying Corps pilots earned their wings on the JN-4, both in Ontario and later in winter facilities at Camp Taliaferro, Texas.

Although ostensibly a training aircraft, the Jenny was extensively modified while in service to undertake additional roles. Due to its robust but easily adapted structure able to be modified with ski undercarriage, the Canadian Jenny was flown year-round, even in inclement weather. The removable turtle-deck behind the cockpits allowed for conversion to stretcher or additional supplies and equipment storage, with the modified JN-4s becoming the first aerial ambulances, carrying out this role both during wartime and in later years. Most of the 6,813 Jennys built were unarmed, although some had machine guns and bomb racks for advanced training. With deployment limited to North American bases, none saw combat service in World War I.

The Curtiss factory in Buffalo, New York, was the largest such facility in the world, but due to production demands, from November 1917 to January 1919, six different manufacturers were involved in production of the definitive JN-4D. Production from spare or reconditioned parts continued sporadically until 1927, although most of the final orders were destined for the civil market in Canada and the United States.

Like the re-engined Curtiss JN-4H version of the most-produced JN-4 subtype, the final production version of the aircraft was the JN-6, powered by a Wright Aeronautical license-built, 150-hp (112-kW) Hispano-Suiza 8 V-8, first ordered in 1918 for the US Navy. A floatplane version was built for the Navy which was so modified, it was essentially a different airframe. This was designated the N-9. In U.S. Army Air Service usage, the JN-4s and JN-6s were configured to the JNS (“S” for “standardized”) model. The Jenny remained in service with the US Army until 1927.

After World War I, thousands were sold on the civilian market, including one to Charles Lindbergh in May 1923, in which he then soloed. Surplus US Army aircraft were sold, some still in their unopened packing crates, for as little as $50, essentially “flooding” the market. With private and commercial flying in North America unhampered by regulations concerning their use, pilots found the Jenny's stability and slow speed made it ideal for stunt flying and aerobatic displays in the barnstorming era between the world wars, with the nearly identical Standard J-1 aircraft often used alongside it. Some were still flying into the 1930s.

JN-4 airframes were used to produce early Weaver Aircraft Company / Advance Aircraft Company / Waco aircraft, such as the Waco 6.

Notable JN Firsts

Between 1917 and 1919, the JN-4 type accounted for several significant aviation “firsts” while in service with the US Army Signal Corps Aviation Section and the United States Marine Corps (USMC) including flying the first U.S. Air Mail in May 1918.

In a series of tests conducted at the U.S. Army's Langley Field in Hampton, Virginia, in July and August 1917, the world's first “plane-to-plane” and “ground-to-plane, and vice versa” communications by radiotelephony (as opposed to radiotelegraphy which had been developed earlier) were made to and from modified US Army JN-4s by Western Electric Company (Bell Labs) design engineers Lewis M. Clement and Raymond Heising, the developers of the experimental wind generator-powered airborne wireless voice transmitter and receiver equipment.

In early 1919, a United States Marine Corps (USMC) JN-4 was also credited with what is believed to be the first successful “dive bombing” attack during the United States occupation of Haiti. USMC pilot Lt Lawson H. Sanderson mounted a carbine barrel in front of the windshield of his JN-4 (previously, an unarmed trainer that had a machine gun mounted in the rear cockpit) as an improvised bomb sight that was lined up with the long axis of his aircraft, loaded a bomb in a canvas mail bag that was attached to the JN-4's belly, and launched a single-handed raid at treetop level, in support of a USMC unit that had been trapped by Haitian Cacos rebels. Although the JN-4 almost disintegrated in the pullout, the attack was effective and led to Sanderson in 1920 developing further dive-bombing techniques to provide Marine pilots with close aerial support to infantry comrades.

JN Series Variants [2]


  • JN-4A — production version of the JN-4, 781 built.
  • JN-4B — This version was powered by an OX-2 piston engine; 76 were built for the U.S. Army, and nine for the U.S. Navy.
  • JN-4C — experimental version, only two were built.
  • JN-4 (Canadian) Canuck — Canadian-built version, 1,260 built by Canadian Aeroplanes Ltd. for the RFC in Canada/RAF in Canada and USAAC: Independently derived from the JN-3, it had a lighter airframe, ailerons on both wings, a bigger and more rounded rudder, and differently shaped wings, stabilizer, and elevators. Its use by the USAAC was curtailed as the lighter structure was claimed to cause more accidents than the US-built aircraft, although no air fatalities were attributed to the structural integrity of the type.
  • JN-4D — improved version, adopting the control stick from the JN-4 (Canadian) 2,812 built.
  • JN-4D-2 — One prototype only, the engine mount was revised to eliminate the down thrust position.
  • JN-4H — two-seat advanced trainer biplane with ailerons on both wings, 929 built for the U.S. Army, notable for introducing the use of the Wright Aeronautical license-built Hispano-Suiza 8 V-8 engine for greater power and reliability.
  • JN-4HT — two-seat, dual-control trainer version.
  • JN-4HB — bombing trainer version.
  • JN-4HG — gunnery trainer version.
  • JN-4HM — communications conversion of JN-4HT, powered by Wright-Hisso E 150-hp (112-kW), six converted, used to fly the first US Air Mail (May-August, 1918).
  • JN-5H — advanced trainer biplane, only one built.
  • JN-6 — improved version of JN-5 trainer biplane series, notably used four ailerons, 1,035 built for the US Army and five for the U.S. Navy.
  • JN-6H — improved version of the JN-6.
  • JN-6BH — bomber trainer version.
  • JN-6HG-1 — two-seat, dual-control trainer version, 560 built from JN-6 production, 34 for US Navy.
  • JN-6HG-2 — single-control gunnery trainer. 90 delivered.
  • JN-6HO — single-control observer trainer version, 106 delivered.
  • JN-6HP — single-control pursuit fighter trainer version.
  • JNS (“standardized”) — During the postwar years of the early 1920s, between 200 and 300 U.S. Army aircraft were upgraded to a common standard of equipment and modernized.

JN “Specials” [2]


  • Allison Monoplane — Conversion of JN-4 (Can) G-CAJL by the Allison Company, Kansas, that mounted a parasol wing in place of the biplane configuration, only one conversion made.
  • Curtiss Special (1918) — A smaller, custom-built, single-seat variant for Katherine Stinson, powered by a 100-;hp (74.5-kW) OXX-6.
  • Ericson Special Three — Some reconditioned aircraft built by Canadian Aeroplanes Ltd. were fitted with a third cockpit.
  • Hennessey Monoplane — A 1926 monoplane conversion by James R. Hennessey, three-place transport, 90-hp Curtiss OX-5, span: 36 ft (11 m) length: 25 ft (7.6 m).
  • Seversky 1926 biplane — A JN-4 modified with a roller/ski undercarriage, one experimental aircraft converted by the Seversky Company.
  • Sperry Monoplane — conversion offered by the Sperry Company that mounted a parasol wing in place of the biplane configuration.
  • Twin JN — An enlarged twin-engined version of the JN-4, they were powered by two OXX-2 piston engines, built in 1916 as the JN-5 for an observation role; among the many other modifications was an enlarged wingspan and new rudder adapted from the Curtiss Model R-4. Two of the series saw action with the US Army on the Mexican border in 1916-1917. A total of eight Twin JNs were built, with two in US Navy service.

JN Operators [2]


JN Military Operators

  • Argentina: Argentine Naval Aviation
  • Australia: Australian Flying Corps; No. 3 Squadron AFC - Used for training; Central Flying School AFC at Point Cook, Victoria.
  • Brazil: Brazilian Naval Aviation (JN-4D variant)
  • Canada: Royal Flying Corps Canada (primarily JN-4 (Can) variant); Royal Canadian Air Force
  • Cuba: Cuban Air Force
  • United Kingdom: Royal Flying Corps; No. 24 Squadron RFC; No. 25 Squadron RFC; Royal Naval Air Service
  • United States: United States Army Signal Corps Aviation Section (1915); United States Army Signal Corps Aeronautical Division (1915-1918); United States Army Air Service (1918 et seq.); United States Marine Corps; United States Navy
  • Republic of China: National Revolutionary Army in the Northern Expedition.

JN Civil Operators

  • Canada: Elliot Air Service, Red Lake, Ontario

Canadian Aeroplanes JN-4 “Canuck” Specifications [3,4]


General Description

  • Type: Biplane Trainer

Dimensions

  • Wing area, including ailerons: 360.6 ft² (33.5 m²)
  • Wing span overall (top): 43 ft 7.325 in. (12.29 m)
  • Wing span overall (lower): 34 ft 8.31 in. (10.57 m)
  • Wing chord: 59.5 in. (1.511 m)
  • Dihedral angle:
  • Sweepback:
  • Stagger: 9.5°
  • Overall length of machine: 27 ft 2.5 in. (8.29 m)
  • Height: 9 ft 11 in. (3.02 m)

Weights and loadings

  • Net weight machine empty: 1,170 lbs (530.70 kg)
  • Gross weight per ft² of surface, including ailerons: 5.1 lbs/ft² (24.90 kg/m²)
  • Loaded weight: 1,920 lbs (872 kg)
  • Empty weight: 1,390 lbs (631 kg)

Power Plant:

  • Curtiss model OX-2 or OX-5 engine: 90 hp
  • Weight of engine: 350 lbs (158.76 kg)
  • Weight per hp: 3.88 lbs/hp (1.76 kg/hp)
  • Bore and stroke: 4×5
  • Normal speed at full motor load: 1,400 rpm
  • Provided capacity, fuel tank: 37 gal. (140.06 L)
  • Fuel consumption per hour, throttle wide open: 8.37 gal./hr (31.68 L/hr)
  • Fuel consumption per hour, average flight: 6 gal./hr (22.71 L/hr)
  • Oil consumption per hour: 0.5 gal./hr (1.89 L/hr)

Performance:

  • Horse power at 1,400 rpm: 90 hp rated
  • Maximum speed: 74 mph (120.7 km/hr)
  • Cruising Speed (approx.): 60 mph (96.5 km/hr)
  • Speed, minimum: 40 mph (64.37 km/hr)
  • Climb in 10 min.: 2,500 ft (762 m)
  • Ceiling: 11,000 ft (3,353 m)

Distribution of useful load (may be changed if desired)

  • Fuel: 200 lbs (90.72 kg)
  • Water: 35 lbs (15.88 kg)
  • Oil: 30 lbs (13.61 kg)
  • Pilot: 175 lbs (79.38 kg)
  • Passenger and other load: 240 lbs (108.86 kg)
  • Total useful load: 680 lbs (308.44 kg)
  • Maximum tank capacity at full motor load: 4.4 hr
  • Tank capacity for ordinary service flight: 6.2 hr
  • Maximum, tank capacity for duration flight: 9 hr

References


  1. Shupek, John. The Skytamer Photo Archive, copyright © 2003 Skytamer Images (Skytamer.com)
  2. Wikipedia. Curtiss JN-4
  3. Jane, Fred T. Jane's All the World's Aircraft 1919, Canadian Aeroplanes, Ltd., Canadian Training Aeroplane (Modified Curtiss J.N.4), Arco Publishing Company, Inc., New York, 1969 Reprint, Library of Congress Catalog Number 69-14964, pp. 2c (First published by Sampson Low and Marston in 1919)
  4. Molson, K.M. and H.A. Taylor. Canadian Aircraft Since 1909, Curtiss JN-4 (Canadian), Canada's Wings, Inc., Stittsville, Ontario, Canada, ISBN 0-920002-11-0, 1982, pg. 233

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