Curtiss JN-4

From Wikipedia, the free encyclopedia
Jump to: navigation, search
JN "Jenny"
Flying jenny cropped.jpg
Curtiss JN-4 Jenny, 1918
Role Trainer
Manufacturer Curtiss
Designer Benjamin D. Thomas
Introduction 1915
Primary users U.S. Army Air Service
Royal Flying Corps
Number built 6,813
Unit cost
$5,465
Variants Curtiss N-9
Curtiss JN-6H

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."[1] 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 America to civil aviation through much of the 1920s.[2]

Design and development[edit]

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.[3] Curtiss built only a limited number of the JN-1 and JN-2 biplanes. The design was commissioned by Glenn Curtiss from Englishman Benjamin D. Thomas, formerly of the Sopwith Aviation Company.[4]

The JN-2 was an equal-span biplane with ailerons controlled by a shoulder yoke located in the aft cockpit.[5] 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.[6]

Curtiss JN-3, the progenitor of the JN-4, deployed to Mexico, around 1916[7]

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.[8] 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.[7]

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.[N 1] The Canadian version was the JN-4 (Canadian), also known as the "Canuck", had some minor differences from the US version, including a lighter airframe, ailerons on both wings, a bigger and more rounded rudder, and differently shaped wings, stabilizer, and elevators.[9]

Operational history[edit]

Curtiss JN-4Ds at Camp Taliaferro, Texas, circa 1918

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.[10] 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).[6][11] 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.[12] Many Royal Flying Corps pilots earned their wings on the JN-4, both in Ontario and later in winter facilities at Camp Taliaferro, Texas.[13]

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.[14] 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.[15] 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.[10] 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.[16]

One of the many daredevil stunts performed by JN-4 pilots was to work with a "wingwalker".

Like the re-engined '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.[10]

After World War I, thousands were sold on the civilian market, including one to Charles Lindbergh in May 1923, in which he then soloed.[17][18] Surplus US Army aircraft were sold, some still in their unopened packing crates, for as little as $50, essentially "flooding" the market.[10][N 2] With private and commercial flying in North America unhampered by regulations concerning their use, pilots found the Jenny's slow speed and stability 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. [N 3] Some were still flying into the 1930s.[16][N 4]

JN-4 airframes were used to produce early Weaver Aircraft Company / Advance Aircraft Company / Waco aircraft, such as the Waco 6.[16]

Notable firsts[edit]

Between 1917 and 1919, the JN-4 type accounted for a number of 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[N 5] 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.[20][21]

In early 1919, a United States Marine Corps (USMC) JN-4 was also credited with what is believed to be the first aircraft to successfully execute a "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.[22] Although the JN-4 almost disintegrated in the pullout, the attack was effective and led to Sanderson in 1920 developing further pioneering dive-bombing techniques to provide Marine pilots with close aerial support to infantry comrades.[23]

Variants[edit]

A JN-4 C227 "Canuck" (USAAS #39158) operated by the US Air Army Air Service in 1918, is now restored and on display at the Canada Aviation and Space Museum.
The most radical development of the Curtiss JN-4 was the Twin JN (or "Twin Jenny") in limited production and service with the US military.

Although the first series of JN-4s were virtually identical to the JN-3, the JN-4 series was based on production orders from 1915–1919.[24]

  • 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.[25]
  • 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.[26]
  • JN-4H — two-seat advanced trainer biplane, 929 built for the U.S. Army, notable for introducing the use of the 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[27]
  • 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[27]
    • 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.

"Specials"[edit]

  • 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[28]
  • Curtiss Special (1918) — a smaller, custom-built, single-seat variant for Katherine Stinson, powered by a 100-;hp (74.5-kW) OXX-6[29] [N 6]
  • Ericson Special Three — Some reconditioned aircraft built by Canadian Aeroplanes Ltd. were fitted with a third cockpit.[10]
  • Hennessey Monoplane — [30] 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)[31][citation needed]
  • Severski 1926 biplane  — a JN-4 modified with a roller/ski undercarriage, one experimental aircraft converted by the Seversky company[32][N 7]
  • Sperry Monoplane — conversion offered by the Sperry Company that mounted a parasol wing in place of the biplane configuration[33]
  • 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.[27]

Operators[edit]

Converted JN-4 ambulance, operated by the Camp Taliaferro medical teams, around 1918
Curtiss JN4-D2 Jenny.svg

Military operators[edit]

 Argentina
 Australia
 Brazil
 Canada
 Cuba
 United Kingdom
 United States
 Republic of China
JN-4 which be used by the Republic of China

Civil operators[edit]

 Canada

Survivors[edit]

The JN-4D on display at the National Museum of the United States Air Force
Curtiss JN-4D at the San Diego Air and Space Museum is being restored (to reskin the wings) prior to future display.[35]

About 50 Jennys survive in museums and with private owners.

For comparison, this 1923 Standard J shows its similarity to the JN-4's appearance.
  • The Cradle of Aviation Museum on Long Island has two Jennys on display. One is the aircraft owned by Charles Lindbergh in which he barnstormed long before his transatlantic flight. Lindbergh purchased this aircraft in Americus, Georgia, for $500 in May 1923, and sold it to his flying student in Iowa the following October. It was restored by the late George Dade in the 1970s and is on loan from the Long Island Early Fliers Club.[39]
  • A JN-4D built in 1917 has been fully restored to flying condition and is on display, as well as being available for flights, at the Golden Age Air Museum at Grimes Airport, Bethel, Pennsylvania.[40]
  • A JN-4D built in 1918, fully restored to flying condition, is on display at the Flying Heritage Collection at Paine Field in Everett, WA.. It is U.S. Army Air Corps "3712" based at March Field, CA.
  • JN-4H, restored as U.S. Navy 6226 (ex-USAAS "38262"), powered by a rare Hispano-Suiza 8, V-8 engine, is on display at the Old Rhinebeck Aerodrome in Rhinebeck, New York. It is still flightworthy and frequently flown during the ORA facility's weekend airshows.[41]

Specifications (JN-4D)[edit]

Data from The Encyclopedia of World Aircraft[42]

JN-4D (line drawing)

General characteristics

Performance

In popular culture[edit]

The "Inverted Jenny" stamp[edit]

"Inverted Jenny" (C-3a P57)

The "Inverted Jenny" (C-3a) is a 24-cent 1918 US Air Mail postage stamp printing error in which the blue central vignette of US Army Curtiss JN-4HM #38262, the nation's first mailplane, appeared as "inverted" on a single sheet of 100 stamps owing to an inadvertent error made by the operator of a hand-rolled spider press by printing the red frame impression upside down after the vignettes had already been printed on the sheet on another press.[43] As the Jenny vignette was only inverted on one sheet, this stamp represents the rarest and most valuable known USPOD printing error of all time. A single example (sheet position 57) sold at auction in 2007 for $977,500.00.[44]

This 1917 Curtiss Jenny still flies on occasion. Its home base is the Call Memorial Museum in Wichita Falls, Texas.

Notable appearances in media[edit]

In 1921, Lee De Forest made a short film Flying Jenny Airplane in his Phonofilm sound-on-film process. The film depicted a JN-4 flying, and recorded the sound of the Jenny, as well. The short documentary was the first production of the De Forest Phonofilm company.[45]

Among many later films depicting the barnstorming era when the Jennys "ruled supreme" and played a feature role, was The Spirit of St. Louis (1957) and The Great Waldo Pepper (1974).[46] In The Court Martial of Billy Mitchell (1955), authentic OX-5 Jennys were showcased as United States Army Air Service training aircraft.[47]

Broadcast on April 15, 1987, by PBS, the National Geographic special entitled "Treasures from the Past" featured the restoration and first flight by Ken Hyde of a JN-4D that would go on to win the "Lindy Award" at the EAA AirVenture Oshkosh '87.[48]

Musician Al Stewart refers to the Jenny in his song "The Immelman Turn" (2005) in which a barnstorming acrobat falls to his death from a Curtiss Jenny attempting the maneuver in a 1923 airshow.

On the TV show The Unit season 4: episode 11 "Switchblade", new character Joss Morgan of Morgan Aviation Company owns a 1917 Curtis "Jenny" and cracks a piston and ends up showing up at the Unit's front fake aviation business looking for help fixing it. She meets her future husband, unit-member Sgt. 1st Class Charles "Carlito" Grey about the piston. He then gets to buy her a drink for telling her what plane the piston was from. He then trades the broken piston for a real piston from the National Air Museum through a friend for his Colt BBQ gun. She was going to show him the "outside loop maneuver".

See also[edit]

References[edit]

Notes
  1. ^ Both the US Army version and the Canadian derivative for the Royal Flying Corps were known as JN-4s. To differentiate between the types, unofficially, the RFC designation was the JN-4 (Canadian).[9]
  2. ^ Surplus JN-4s typically fetched between $200 and $500, depending on condition.[10]
  3. ^ The front cockpit that was normally for the student in military training was usually used for passengers in postwar joy rides, so the pilot could keep an eye on his paying customer/s.[16]
  4. ^ The JN-4 Canuck was often chosen for barnstorming as the lighter, more responsive, and more economical variant was also in large supply.[16]
  5. ^ Quote: "A JN-4-d plane was used; speed was successful, transmitting about 3 miles from plane to plane and was also received from ground to plane, and vice versa." [19]
  6. ^ Stinson's aircraft built to her specifications was used for fundraising tours for the American Red Cross. During exhibition flights in Canada, she set a Canadian distance and endurance record, and made the second air mail flight in Canada between Calgary and Edmonton, Alberta. A replica is at the Alberta Aviation Museum.[29]
  7. ^ The name "Severski" was a play on designer Alexander P. de Seversky's name, emphasizing the use of skis.[32]
Citations
  1. ^ Auliard 2009, p. 44.
  2. ^ Rumerman, Judy. "The Curtiss JN-4 "Jenny". U.S. Centennial of Flight Commission, 2003.
  3. ^ Roseberry 1972, p. 477.
  4. ^ Angelucci 1973, p. 41.
  5. ^ Bowers 1966, p. 7.
  6. ^ a b Donald 1997, pp. 279–280.
  7. ^ a b House 2003 p. 168.
  8. ^ Larson 2004, pp. 19–20.
  9. ^ a b Molson and Taylor 1982, p. 219.
  10. ^ a b c d e f Winchester 2004, p. 88.
  11. ^ "The Engine that Saved Aviation: OX-5." Air Classics, Issue 3, Fall 1965, p. 30.
  12. ^ Molson and Taylor 1982, p. 225.
  13. ^ Chajkowsky 1979, p. 55.
  14. ^ "Royal Flying Corps Starts Training in Toronto." abheritage.ca. Retrieved: 10 September 2011.
  15. ^ Hurd and Jernigan 2002, p. 7.
  16. ^ a b c d e Winchester 2004, p. 89.
  17. ^ Lindbergh 1927, pp. 39–43.
  18. ^ "Charles Lindbergh's First Solo Flight & First Plane." Charles Lindbergh official site.
  19. ^ "Report of the Chief Signal Officer to the Secretary of War, October 15, 1919". Annual Report, War Department, 1919, pp. 262–263.
  20. ^ "Handwritten letter, dated August 18, 1917, from Western Electric Co (Bell Labs) design engineer Lewis M. Clement to Vesta L. Clement, his wife, with a detailed first-person account of the first successful test of 'plane-to-plane' and 'plane-to-ground' radiotelephony from JN-4-d airplanes in flight conducted that day at Langley Field, VA." The Cooper Collection of U.S. Aviation History (Private collection: original letter location), Ardmore, Pennsylvania.
  21. ^ "Lewis Mason Clement: Pioneer of Radio." CPRR.org, September 2010. Retrieved: 5 September 2011.
  22. ^ "Debunking dive bomber myths." Flightpath, Volume 21, Number 4, 17 April 2010.
  23. ^ Nowarra 1982, p. 8.
  24. ^ Auliard 2009, pp. 46–47.
  25. ^ Molson and Taylor 1982, pp. 225–226.
  26. ^ Auliard 2009, p. 46.
  27. ^ a b c Auliard 2009, p. 47.
  28. ^ Molson 1964, p. 62.
  29. ^ a b Chalmers, John. "You've Got Mail... an Alabaman Aviatrix in Alberta: Katherine Stinson and the Curtiss Special." Vintage News, Retrieved: 10 September 2011.
  30. ^ "Hennessey Monoplane." San Diego Air and Space Museum Archives. Retrieved: 6 September 2011.
  31. ^ "Hennessey." Aerofiles. Retrieved: 6 September 2011.
  32. ^ a b "Severski." Aerofiles. Retrieved: 10 September 2011.
  33. ^ "Sperry 'Commercial' Wing." Flight, 23 July 1921.
  34. ^ Molson 1974, p. 4.
  35. ^ "Aircraft Collections." San Diego Air and Space Museum. Retrieved: 6 September 2011.
  36. ^ "1917 Curtiss JN-4D, WAAAM's Crown Jewel." waaamuseum.org. Retrieved: 5 September 2011.
  37. ^ United States Air Force Museum 1975, p. 8.
  38. ^ "JN-4D 'Jenny'." The Museum of North Texas History. Retrieved: 4 September 2011.
  39. ^ "Curtiss JN-4 'Jenny', Buffalo, NY, 1918." Cradle of Aviation Museum, 2010. Retrieved: 5 September 2011.
  40. ^ "1918 Curtiss JN4D 'Jenny'." Golden Age Air Museum. Retrieved: 10 September 2011.
  41. ^ "Old Rhinebeck Aerodrome — Curtiss JN-4H Jenny." oldrhinebeck.org. Retrieved: 4 October 2009.
  42. ^ Donald 1997, p. 280.
  43. ^ "24c Curtiss Jenny invert single." Smithsonian National Postal Museum. Retrieved: 4 September 2011.
  44. ^ "Robert A. Siegel Auction #946a." SiegelAuctions.com.
  45. ^ "Flying Jenny Airplane" (1921). IMDB, Retrieved: 4 September 2011.
  46. ^ Harwick and Schnepf 1989, pp. 57, 60.
  47. ^ Harwick and Schnepf 1989, p. 55.
  48. ^ Chase, Gene. "From Jets to Jennies: Ken Hyde's Grand Champion Curtiss JN4D." Sport Aviation,Volume 36, No. 11, November 1987, p. 52.
Bibliography
  • Angelucci, Enzo. Great Aeroplanes of the World. London: Hamlyn, 1973. ISBN 0-600-38663-5.
  • Auliard, Gilles. "Maiden of the Skies." Air Classics, Volume 45, No. 4, April 2009.
  • Bowers, Peter M. "Jenny's Younger Sister." Air Progress, Volume 18, No. 2, February/March 1966.
  • Chajkowsky, William E. Royal Flying Corps: Borden to Texas to Beamsville. Eden Prairie, Ontario, Canada: Boston Mills Press, 1979. ISBN 978-0-919822-23-8.
  • Donald, David, ed. The Encyclopedia of World Aircraft. London: Aerospace Publishing, 1997. ISBN 1-85605-375-X.
  • Harwick, Jack and Ed Schnepf. "A Viewer's Guide to Aviation Movies". The Making of the Great Aviation Films, General Aviation Series, Volume 2, 1989.
  • House, Kirk W. Hell-Rider to King of the Air. Warrendale, Pennsylvania: SAE International, 2003. ISBN 0-7680-0802-6.
  • Hurd, William W. and John G. Jernigan. Aeromedical Evacuation: Management of Acute and Stabilized Patients. New York: Springer Publishing, 2002. ISBN 978-0-387-98604-3.
  • Jones, A.D. Aerial Mail Service: A Chronology of the Early United States Government Air Mail, March–December, 1918. Mineola, New York: The American Air Mail Society, 1993. ISBN 978-0-939429-14-1.
  • Larson, Lt. Col. George A., USAF (Ret.). "Hunting Pancho: The 1st Aero Aquadron's Air Operations in support of the Army's 1916 punitive expedition." Air Classics, Volume 40, no. 6, June 2004.
  • Lindbergh, Charles A. "WE" New York & London: G.P. Putnam's Sons (The Knickerbocker Press), 1927.
  • Molson, Ken M. "The Canadian JN-4." Canadian Aeronautics and Space Journal, Volume 10, No. 3, March 1964.
  • Molson, K.M. Pioneering in Canadian Air Transport. Winnipeg: James Richardson & Sons, Ltd., 1974. ISBN 0-919212-39-5.
  • Molson, Ken M. and Harold A. Taylor. Canadian Aircraft Since 1909. Stittsville, Ontario: Canada's Wings, Inc., 1982. ISBN 0-920002-11-0.
  • Nowarra, Heinz J. Gezielter Sturz. Die Geschichte der Sturzkampfbomber aus aller Welt (in German). Stuttgart: Motorbuch Verlag, 1982. ISBN 3-87943-844-7.
  • Roseberry, C.R. Glenn Curtiss: Pioneer of Flight, A Biography. Garden City, New York: Doubleday & Company, 1972. ISBN 0-8156-0264-2.
  • United States Air Force Museum Guidebook. Wright-Patterson AFB, Ohio: Air Force Museum Foundation, 1975.
  • Winchester, Jim, ed. "Curtiss JN-4 'Jenny'." Biplanes, Triplanes and Seaplanes (Aviation Factfile). London: Grange Books plc, 2004. ISBN 1-84013-641-3.

External links[edit]