Autogyro
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An autogyro, also known as gyroplane, gyrocopter, or rotaplane, is a type of rotorcraft which uses an unpowered rotor in autorotation to develop lift, and an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust. While similar to a helicopter rotor in appearance, the autogyro's rotor must have air flowing up and through the rotor disc in order to generate rotation. Invented by Juan de la Cierva to create an aircraft that could safely fly at slow speeds, the autogyro was first flown on 9 January 1923, at Cuatro Vientos Airfield in Madrid.[1] De la Cierva's aircraft resembled the fixed-wing aircraft of the day, with a front-mounted engine and propeller in a tractor configuration to pull the aircraft through the air. Late-model autogyros patterned after Dr. Igor Bensen's designs feature a rear-mounted engine and propeller in a pusher configuration. The term Autogiro was a trademark of the Cierva Autogiro Company, and the term Gyrocopter was used by E. Burke Wilford who developed the Reiseler Kreiser feathering rotor equipped gyroplane in the first half of the twentieth century. The latter term was later adopted as a trademark by Bensen Aircraft.
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Configuration
An autogyro is characterized by a free-spinning rotor that turns due to passage of air upwards through the rotor. The vertical component of the total aerodynamic reaction of the rotor gives lift for the vehicle, and sustains the autogyro in the air. A separate propeller provides forward thrust, and can be placed in a tractor configuration with the engine and propeller at the front of the fuselage (e.g., Cierva), or pusher configuration with the engine and propeller at the rear of the fuselage (e.g., Bensen).
Whereas a helicopter works by forcing the rotor blades through the air, pushing air downwards, the autogyro rotor blade generates lift in the same way as a glider's wing by changing the angle of the air as it moves upwards and backwards relative to the rotor blade. The free-spinning blades turn by autorotation; the rotor blades are angled so that they not only give lift, but the angle of the blades causes the lift to accelerate the blades' rotation rate, until the rotor turns at a stable speed with the drag and thrust forces in balance.
Pitch control of the autogyro is by tilting the rotor fore and aft; roll control is by tilting the rotor laterally (side to side). Three designs to affect the tilt of the rotor are a tilting hub (Cierva), swashplate (Air & Space 18A), or servo-flaps (Kaman SAVER). A rudder provides yaw control. On pusher configuration autogyros, the rudder is typically placed in the propeller slipstream to maximize yaw control at low airspeed (but not always, as seen in the McCulloch J-2, with twin rudders placed outboard of the propeller arc).
Flight controls
There are three primary flight controls: control stick, rudder pedals, and throttle. The control stick is termed cyclic and tilts the rotor in the desired direction to provide pitch and roll control. The rudder pedals provide yaw control, and the throttle controls engine power.
Secondary flight controls include the rotor transmission clutch, also known as a pre-rotator, which when engaged drives the rotor to start it spinning before takeoff, and collective pitch to reduce blade pitch before driving the rotor. Collective pitch controls are not usually fitted to autogyros, but can be found on the Air & Space 18A and McCulloch J-2 and the Westermayr Tragschrauber and are capable of near VTOL performance. Unlike a helicopter, autogyros without collective pitch need a runway to takeoff; however they are capable of landing with a very short, or zero ground roll.
Pusher vs tractor configuration
Modern autogyros typically follow one of two basic configurations. The most common design is the pusher configuration, where the engine and propeller are located behind the pilot and rotor mast, such as in the Bensen "Gyrocopter". It was developed by Igor Bensen in the decades following World War II, and came into widespread use shortly afterward.
Less common today is the tractor configuration. In this version the engine and propeller are located at the front of the aircraft, ahead of the pilot and rotor mast. This was the primary configuration in early autogyros, but became less common after the advent of the helicopter. It has enjoyed a revival since the mid 1970s however, in the "Little Wing" autogyro concept.
History
Juan de la Cierva was a Spanish engineer and aeronautical enthusiast. In 1921, he participated in a design competition to develop a bomber for the Spanish military. De la Cierva designed a three-engined aircraft, but during an early test flight, the bomber stalled and crashed. De la Cierva was troubled by the stall phenomenon and vowed to develop an aircraft that could fly safely at low airspeeds. The result was the first successful rotorcraft, which he named Autogiro in 1923. De la Cierva's autogyro used an airplane fuselage with a forward-mounted propeller and engine, a rotor mounted on a mast, and a horizontal and vertical stabilizer.
Early development
De la Cierva's first three designs (C.1, C.2, and C.3) were unstable due to aerodynamic and structural deficiencies in their rotors. His fourth design, the C.4, made the first successful flight of an autogyro on 9 January 1923, piloted by Alejandro Gomez Spencer at Cuatro Vientos airfield in Madrid, Spain. De la Cierva had fitted the rotor of the C.4 with flapping hinges to attach each rotor blade to the hub. The flapping hinges allowed each rotor blade to flap, or move up and down, to compensate for dissymmetry of lift, the difference in lift produced between the right and left sides of the rotor as the autogyro moves forward. Three days later, the engine failed shortly after takeoff and the aircraft descended slowly and steeply to a safe landing, validating De la Cierva's efforts to produce an aircraft that could be flown safely at low airspeeds.
De la Cierva developed his C.6 model with the assistance of Spain's Military Aviation establishment, having expended all his funds on development and construction of the first five prototypes. The C.6 first flew in February 1925, including a flight of 10.5 km (7 miles) from Cuatro Vientos airfield to Getafe airfield in about 8 minutes, a significant accomplishment for any rotorcraft of the time. Shortly after De la Cierva's success with the C.6, Cierva accepted an offer from Scottish industrialist James G. Weir to establish the Cierva Autogiro Company in England, following a demonstration of the C.6 before the British Air Ministry at RAE Farnborough, on 20 October 1925. Britain had become the world centre of autogyro development.
A crash in February 1927, due to blade root failure, led to an improvement in rotor hub design. A drag hinge was added in conjunction with the flapping hinge to allow each blade to move fore and aft and relieve in-plane stresses, generated as a byproduct of the flapping motion. This development led to the Cierva C.8, which, on 18 September 1928, made the first rotorcraft crossing of the English Channel followed by a tour of Europe.
The U.S. industrialist Harold Frederick Pitcairn, upon learning of the successful flights of the autogyro, had previously visited De la Cierva in Spain. In 1928 he visited him again, in England, after taking a C.8 L.IV test flight piloted by Arthur H.C.A. Rawson. Being particularly impressed with the autogyro's safe vertical descent capability, Pitcairn purchased a C.8 L.IV with a Wright Whirlwind engine. Arriving in the United States on 11 December 1928 accompanied by Rawson, this autogyro was redesignated C.8W. Subsequently, production of autogyros was licensed to a number of manufacturers, including the Pitcairn Autogiro Company in the U.S. and Focke-Wulf of Germany.
Development of the autogyro continued in search for a means to accelerate the rotor prior to takeoff (called prerotating). Rotor drives initially took the form of a rope wrapped around the rotor axle and then pulled by a team of men to accelerate the rotor - this was followed by a long taxi to bring the rotor up to speed sufficient for takeoff. The next innovation was flaps on the tail to redirect the propeller slipstream into the rotor while on the ground. This design was first tested on a C.19 in 1929. Efforts in 1930 had shown that development of a light and efficient mechanical transmission was not a trivial undertaking. But in 1932, the Pitcairn-Cierva Autogiro Company of Willow Grove, Pennsylvania, finally solved the problem with a transmission driven by the engine.
De la Cierva's early autogyros were fitted with fixed rotor hubs, small fixed wings, and control surfaces like those of a fixed wing aircraft. At low airspeeds, the control surfaces became ineffective and could readily lead to loss of control, particularly during landing. In response, Cierva developed a direct control rotor hub, which could be tilted in any direction by the pilot. De la Cierva's direct control was first developed on the Cierva C.19 Mk. V and saw production on the Cierva C.30 series of 1934. In March 1934 this type of autogyro became the first rotorcraft to take off and land on the deck of a ship, when a C.30 performed trials onboard the Spanish navy seaplane tender Dédalo off Valencia.[2]
Later that year, during the leftist Asturias' revolt in October, an autogyro made a reconnaissance flight for the loyal troops, marking the first military employment of a rotorcraft.[3]
When improvements in helicopters made them practical, autogyros became largely neglected. They were, however, used in the 1930s by major newspapers, and by the US Postal Service for mail service between the Camden, NJ airport (USA) and the top of the post office building in downtown Philadelphia, Pennsylvania (USA).[4]
World War II
In World War II, Germany pioneered a very small gyroglider rotor kite, the Focke-Achgelis Fa 330 "Bachstelze" (Water-wagtail), towed by U-boats to provide aerial surveillance.
The Imperial Japanese Army developed the Kayaba Ka-1 Autogyro for reconnaissance, artillery-spotting, and anti-submarine uses. The Ka-1 was based on an American design first imported to Japan in 1938. The craft was initially developed for use as an observation platform and for artillery spotting duties. The Army liked the craft's short take-off span, and especially its low maintenance requirements. In 1941 production began, with the machines assigned to artillery units for spotting the fall of shells. These carried two crewmen: a pilot and a spotter.
Later, the Japanese Army commissioned two small aircraft carriers intended for coastal antisubmarine (ASW) duties. The spotter's position on the Ka-1 was modified in order to carry one small depth charge. Ka-1 ASW autogyros operated from shore bases as well as the two small carriers. They appear to have been responsible for at least one submarine sinking.
The autogyro was used to calibrate the coastal radar stations during and after the Battle of Britain.[5]
Postwar developments
The autogyro was resurrected after World War II when Dr. Igor Bensen, a Russian immigrant, saw a captured German U-Boat's Fa 330 gyroglider and was fascinated by its characteristics. At work he was tasked with the analysis of the British military "Rotachute" gyro glider designed by expatriate Austrian Raoul Hafner. This led him to adapt the design for his own purposes and eventually market the B-7. Bensen submitted an improved version, the Bensen B-8M, for testing to the United States Air Force, which designated it the X-25. The B-8M was designed to use surplus McCulloch engines used on flying unmanned target drones.
Ken Wallis developed a miniature autogyro craft, the Wallis autogyro, in England in the 1960s, and autogyros built similar to Wallis' design appeared for a number of years. Ken Wallis' designs have been used in various scenarios including military training, police reconnaissance, and in another case a search for the Loch Ness Monster.
Three different autogyro designs have been certified by the Federal Aviation Administration for commercial production: the Umbaugh U-18/Air & Space 18A of 1965, the Avian 2-180 Gyroplane of 1967, and the McCulloch J-2 of 1972. All have been commercial failures, for various reasons.
Bensen Gyrocopter
The basic Bensen Gyrocopter design is a simple frame of square aluminium or galvanized steel tubing, reinforced with triangles of lighter tubing. It is arranged so that the stress falls on the tubes, or special fittings, not the bolts. A front-to-back keel mounts a steerable nosewheel, seat, engine, and a vertical stabilizer. Outlying mainwheels are mounted on an axle. Some versions may mount seaplane-style floats for water operations.
Bensen-type autogyros use a pusher configuration for simplicity and to increase visibility for the pilot. Power can be supplied by a variety of engines. McCulloch drone engines, Rotax marine engines, Subaru automobile engines, and other designs have been used in Bensen-type designs.
The rotor is mounted atop the vertical mast. The rotor system of all Bensen-type autogyros is of a two-blade teetering design. There are some disadvantages associated with this rotor design, but the simplicity of the rotor design lends itself to ease of assembly and maintenance and is one of the reasons for its popularity. Aircraft-quality birch was specified in early Bensen designs, and a wood/steel composite is used in the world speed record holding Wallis design. Gyroplane rotor blades are made from other materials such as aluminium and GRP-based composite blades.
Due to Bensen's pioneering of the concept and the popularity of his design, "Gyrocopter" has become a genericized trademark for pusher configuration autogyros.
Certification by national aviation authorities
US certification
A certificated autogyro must meet mandated stability and control criteria; in the United States these are set forth in Federal Aviation Regulations Part 27: Airworthiness Standards: Normal Category Rotorcraft.[6] The U.S. Federal Aviation Administration issues a Standard Airworthiness Certificate to qualified autogyros. Amateur-built or kit-built aircraft are operated under a Special Airworthiness Certificate in the Experimental category.[7] Per FAR 1.1, the FAA uses the term "gyroplane" for all autogyros, regardless of the type of Airworthiness Certificate.
UK certification
Some autogyros, such as the Rotorsport MT03,[8] have type approval by the United Kingdom Civil Aviation Authority (CAA) under British Civil Airworthiness Requirements CAP643 Section T.[9] Others operate under a permit to fly issued by the Popular Flying Association– similar to the US experimental aircraft certification. However, the CAA's assertion that autogyros have a poor safety record means that permit to fly will only be granted to existing types of autogyro. All new types of autogyro must be submitted for full type approval under CAP643 Section T.[10]
In 2005, the CAA issued a mandatory permit directive (MPD) which restricted operations for single seat autogryos, and were subsequently integrated into CAP643 Issue 3 published on 12 August 2005.[9] The restrictions are concerned with the offset between the centre of gravity and thrust line, and apply to all aircraft unless evidence is presented to the CAA that the CG/Thrust Line offset less than 2 inches (5 cm) in either direction. The restrictions are summarised as follows:
- Aircraft with a cockpit/nacelle may only be operated by pilots with more than 50 hours solo flight experience following the issue of their licence.
- Open frame aircraft are restricted to a minimum speed of 30 mph (26 knots), except in the flare.
- All aircraft are restricted to a Vne of 70 mph (61 knots)
- Flight is not permitted when surface winds exceed 17 mph (15 knots) or if the gust spread exceeds 12 mph (10 knots)
- Flight is not permitted in moderate, severe or extreme turbulence and airspeed must be reduced to 63 mph (55 knots) if turbulence is encountered mid-flight.
World records
In 1931, Amelia Earhart flew a Pitcairn PCA-2 to a women's world altitude record of 18,415 ft (5,613 m).[11]
Wing Commander Ken Wallis has held most of the autogyro world records during his autogyro flying career. These include the speed record of 186 km/h (111.7 mph), and the straight-line distance record of 869.23 km (543.27 miles). On 16 November 2002, Wallis increased the speed record to 207.7 km/h (129.1 mph)– and simultaneously set another world record as the oldest pilot to set a world record.[12]
The autogyro is one of the last remaining types of aircraft which has not yet been used to circumnavigate the globe. Expedition Global Eagle was the first attempt in history to circumnavigate the globe using an autogyro.[13] The expedition set the record for the longest flight over water by an autogyro during the segment from Muscat, Oman to Karachi.[14] The attempt was finally abandoned due to bad weather after a trip totalling 7,500 miles (12,100 km).
In February 2003, a year before the circumnavigation attempt, the Global Eagle piloted by Warrant Officer Barry Jones also broke the world range record by flying non-stop from Culdrose in Cornwall to Wick in Scotland, a total of 580 miles (928 km) breaking the old record held by Wing Commander Ken Wallis.[15]
Andrew Keech made a transcontinental flight from Kitty Hawk, North Carolina to San Diego, California in October 2003 and set 3 world records for speed over a recognized course. The 3 records were verified by tower personnel or by official observers of the United States' National Aeronautic Association (NAA). On 9 February 2006, he broke two of his world records and set a record for distance, ratified by the Fédération Aéronautique Internationale (FAI); Speed over a closed circuit of 500 km (311 mi) without payload: 168.29 km/h (104.57 mph), speed over a closed circuit of 1,000 km (621 mi) without payload: 165.07 km/h (102.57 mph), and distance over a closed circuit without landing: 1,019.09 km (633.23 mi).[16]
In popular culture
An indication of the pre-World War II popularity of the autogyro, its subsequent decline and later rise of interest can be inferred from its appearances in the films and comics of the day. Notable appearances include:
- In the film International House (1933), W. C. Fields's character flies around the globe in his autogyro The Spirit of Brooklyn.
- In the film It Happened One Night (1934), the groom and pilot King Westley arrives dramatically for the wedding in an autogyro.
- An autogyro appears (in what is obviously stock footage or animation) in Alfred Hitchcock's film The 39 Steps (1935) in a scene in Scotland where the hero is escaping the police.
- In the classic science fiction film of H.G. Wells' Things to Come (1936), the heroes of the story arrive dramatically at the Space Gun in an Art Deco-style autogyro, to mitigate the destruction of the Space Gun by extremists, which will carry two people to the Moon in the year 2036. The autogyro in the film was designed by celebrated art deco designer Norman Bel Geddes, who assisted production designer William Cameron Menzies on the look of the world of tomorrow.
- Little Nellie, the autogyro featured in the 1967 James Bond film You Only Live Twice, was a Ken Wallis WA-116 design and was piloted by Wallis in its film scenes. In the film it was shipped by Q in four suitcases and assembled before use.[17][18]
- In the 70s a Finnish autogyro, the ATE-3, designed by Jukka Tervamaki took part in the film "Leikkikalugansteri" (Toy Gangster).
- In the 1979 anime film The Castle of Cagliostro, Count Cagliostro flies an autogyro into his castle, which is later used by Fujiko Mine, Arsene Lupin III and Lady Clarisse d'Cagliostro in their flight from it.
- A Wallis WA-116T two seat autogyro is flown by character Ben Driscoll in an episode of the 1979 USA NBC-TV television science-fiction film The Martian Chronicles.[19][20]
- An autogyro was heavily featured in the second Mad Max (The Road Warrior) film, released in 1981, appearing in several scenes with its pilot, the Gyro Captain, as a major character. The pilot used in the flying sequences was Gerry Goodwin, doubling for the actor, Bruce Spence.[21]
- Fictional comic characters Doc Savage,[22] and The Shadow featured autogyros in their 1930s and 1940s pulp magazine adventures, as did Tom Strong in his pulp styled comic.[23]
- Batman's first aircraft was an autogyro. The "Batgyro" was introduced in Detective Comics #31 in September 1939. It only made three appearances before being replaced by a more conventional fixed wing aircraft.
- At the end of the film The Rocketeer, Howard Hughes pilots an autogyro to rescue a couple from the roof of an exploding zeppelin.
- The 1996 video game "Pilotwings 64", for the Nintendo 64 console, features flyable, missile-laden autogyros
- In the Mother Simpson episode of The Simpsons, Mr. Burns asks a postal worker if he has missed the 4:30 autogyro to Siam, as he is worried that his aeromail will not reach the Prussian consulate on time.
- The 2000 video game "Crimson Skies" for the PC and its 2003 sequel "Crimson Skies: High Road to Revenge" for the XBOX console include autogyros as flyable aircraft.
- A gyrocopter armed with a machine gun is an unlockable reward in the video game Grand Theft Auto: Vice City Stories.
See also
- Carter Copter
- Fairey Rotodyne
- Gyrodyne - an autogyro that powers the rotor as necessary
- Gyroglider
- Helicopter
- List of autogyro models
- Piasecki Aircraft Corporation
- Rotary-wing hang glider
Notes
- ↑ Vector Flight
- ↑ "The first Dedalo was an aircraft transportation ship and the first in the world from which an autogyro took off and landed." Naval Ship Systems Command, US: Naval Ship Systems Command technical news.1966, v. 15-16, page 40
- ↑ Payne, Stanley G. (1993). Spain's first democracy: the Second Republic, 1931-1936. Univ of Wisconsin Press, p. 219. ISBN 0299136744
- ↑ Pulle, Matt (5 July 2007). "Blade Runner". Dallas Observer (Dallas, Tx) Vol. 27 (Issue 27): pp. 19–27. http://www.dallasobserver.com/2007-07-05/news/blade-runner/
- ↑ Burns, R.W. (1988). Radar Development to 1945. IEE. p. 139. ISBN 0863411398. http://books.google.com/?id=cBbnDiTUx6YC&pg=PA139&lpg=PA139&dq=autogyro+radar+callibration.
- ↑ "Current FAR by Part". Federal Aviation Administration. http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/MainFrame?OpenFrameSet. Retrieved 2007-11-13.
- ↑ "Experimental Category Operating Amateur-built, Kit-built, or Light-sport Aircraft". Federal Aviation Administration. http://www.faa.gov/aircraft/air_cert/airworthiness_certification/sp_awcert/experiment/expt_operating/. Retrieved 2007-11-13.
- ↑ "Type: RotorSport UK MT-03" (PDF). Gyroplane type approval data sheet (TADS). United Kingdom Civil Aviation Authority. http://www.caa.co.uk/docs/1419/srg_acp_TADSGyroplane_BG01_Issue1.pdf. Retrieved 2007-11-13.
- ↑ 9.0 9.1 "CAP 643 British Civil Airworthiness Requirements Section T Light Gyroplanes" (PDF). United Kingdom Civil Aviation Authority. http://www.caa.co.uk/docs/33/CAP643.PDF. Retrieved 2007-11-13.
- ↑ "CAP 733 Permit to Fly Aircraft" (PDF). United Kingdom Civil Aviation Authority. p. 20, Chapter 3, Section 5. http://www.caa.co.uk/docs/33/CAP733.PDF. Retrieved 2007-11-13.
- ↑ "Achievements". Official Amelia Earhart website. http://www.ameliaearhart.com/about/achievements.html. Retrieved 2008-01-09.
- ↑ "List of records established by Kenneth H. Wallis". Fédération Aéronautique Internationale. http://records.fai.org/pilot.asp?from=rotorcraft&id=335. Retrieved 2007-10-07.
- ↑ BBC News You only live twice? A Nottingham man is part of a team hoping to circumnavigate the globe in one of James Bond's gadgets. Quote: "The autogyro is the only aircraft never to circumnavigate the globe. But now a team of soldiers are bidding to do just that and make a piece of aviation history."
- ↑ The Yorkshire Post The Eagle has landed – but pilot vows to try again Quote: "509-mile flight from Muscat to Karachi, the longest over water by an autogyro" 22 October 2004
- ↑ Story of the record
- ↑ "Aviation and Space World Records". Fédération Aéronautique Internationale. http://records.fai.org/pilot.asp?from=rotorcraft&id=4246. Retrieved 2008-01-09.
- ↑ "Trivia: You Only Live Twice". Internet Movie Database. http://imdb.com/title/tt0062512/trivia. Retrieved 2007-10-07.
- ↑ "K.H. Wallis". Internet Movie Database. http://imdb.com/name/nm0909250/. Retrieved 2007-10-07.
- ↑ "Wing Commander K. H. Wallis". Norfolk & Norwich Group of Advanced Motorists. http://www.nnam.org/Wallisinfo.htm. Retrieved 29 January 2009.
- ↑ "Kenneth Wallis". gyroplanpassion.com. http://www.gyroplanepassion.com/Ken_Wallis.html. Retrieved 29 January 2009.
- ↑ "Gerry Goodwin". Internet Movie Database. http://imdb.com/name/nm0329462/. Retrieved 2007-10-07.
- ↑ "Doc piloting his gyro". Art Nocturne. http://mysite.verizon.net/pulps.fan/Art-Nocturne/gyro.htm. Retrieved 2007-10-07.
- ↑ "Tom Strong and his Phantom Autogyro". America's Best Comics. http://www.leguy.de/comics/abc/tomstrong/10.html. Retrieved 2007-10-07.
References
External links
- Air & Space 18A gyroplane.
- Australian Sport Rotorcraft Association
- British Rotorcraft Association
- Gyroplane/ Gyrocopter/ Autogyro/ Autogiro FAQ, Frequently Asked Questions on gyroplanes
- The Gyrobee, and ultralight autogyro
- Bensen Aircraft, Historic website for Bensen Gyrocopter plans, videos, pictures and more.
- GyroPilot, for people interested in autogyros
- Gyroplane Passion All things relating to gyroplanes
- Jeff Lewis' in-depth history of the Autogyro
- Popular Rotorcraft Association (United States)
- gyrowiki.com Gyroplane Articles and resources.
- Golden Age Pioneers: Juan de la Cierva (Inventor of the autogyro), courtesy of Bomberguy
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