Fairey Rotodyne
Encyclopedia
The Fairey Rotodyne was a 1950s British
compound gyroplane designed and built by Fairey Aviation
and intended for commercial and military applications. A development of the earlier Gyrodyne which had established a world helicopter speed record, the Rotodyne featured a tip-jet
-powered rotor that burned a mixture of fuel and compressed air bled from two wing-mounted Napier Eland
turboprop
s. The rotor was driven for vertical takeoffs, landings and hovering, as well as low-speed translational flight, and autorotated during cruise flight with all engine power applied to two propellers. Although promising in concept and successful in trials, the Rotodyne program was eventually cancelled when a combination of politics and lack of commercial orders arising from concerns over high levels of rotor tip-jet noise doomed the project.
, a unique aircraft in its own right that defined a third type of rotorcraft, including autogyro
and helicopter. Having little in common with the later Rotodyne, it was characterised by its inventor, Dr. J.A.J. Bennett, formerly Chief Technical Officer of the pre-Second World War
Cierva Autogiro Company
as an intermediate aircraft designed to combine the safety and simplicity of the autogyro with hovering performance. Its rotor was driven in all phases of flight with collective pitch being an automatic function of shaft torque, with a side-mounted propeller providing both thrust for forward flight and rotor torque correction. The FB-1 set a world airspeed record in 1948, but a fatal accident due to poor machining of a rotor blade flapping link retaining nut terminated development of the pure gyrodyne. The second FB-1 was modified to investigate a tip-jet driven rotor with propulsion provided by propellers mounted at the tip of each stub wing. This was renamed the Jet Gyrodyne
, which despite its name, was a compound autogyro.
Fairey put forward their various designs for the proposed BEA Bus, which were revised over the years, and received government funding. However, getting access to engines proved to be difficult, with first Rolls-Royce
then Armstrong Siddeley
claiming lack of resources. The Ministry of Supply
contracted in 1953 for the building of the prototype (serial number
XE521).
With a view to an aircraft that would meet regulatory approval in the shortest time, Fairey's designers worked to meet the Civil Airworthiness requirements for both helicopters and similar sized twin engined aircraft. A one-sixth scale rotorless model was extensively wind-tunnel tested for fixed-wing performance. A smaller (1/15th-scale) model with powered rotot was used for downwash investigations.
The Rotodyne had a large, four-bladed rotor
and two Napier
Eland
N.E.L.3 turboprops, one mounted under each of the fixed wings.
For takeoff and landing, the rotor was driven by tip-jets. The air was produced by compressors driven through a clutch off the main engines. This was fed through ducting in the leading edge of the wings and up to the rotor head. Each engine supplied air for a pair of opposite rotors; the compressed air was mixed with fuel and burned. As a torqueless rotor system, no anti-torque correction system was required, though propeller pitch was controlled by the rudder
pedals for low-speed yaw control. The propellers provided thrust for translational flight while the rotor autorotated. The cockpit controls included a cyclic and collective pitch lever, as in a conventional helicopter.
The rotor blades were a symmetrical aerofoil around a load-bearing spar. The aerofoil was made of steel and light alloy to because of centre of gravity concerns. Equally the spar was formed from a thick machined steel block to the fore and a lighter thinner section formed from folded and rivetted steel to the rear. The compressed air was channeled through three steel tubes within the blade. The tip jet combustion chambers were made from Nimonic 80
with liners made from Nimonic 75.
While the prototype was being built, funding for the programme reached a crisis. Cuts in defence spending led the Ministry of Defence
to withdraw support, pushing the burden of the costs onto any possible civilian customer. The Government agreed to continued funding only if, among other qualifications, Fairey and Napier (through their parent English Electric
) contributed to development costs of the Rotodyne and the Eland engine respectively.
Although J.A.J. Bennett had left Fairey to join Hiller Helicopters
in California, the prototype, its development assumed by Dr. George S. Hislop, made its first flight on 6 November 1957 piloted by Chief Helicopter Test Pilot Squadron Leader
W. Ron Gellatly and Assistant Chief Helicopter Test Pilot Lieutenant Commander
John G.P. Morton as Second Pilot.
The first successful transition from vertical to horizontal and back to vertical flight was achieved on 10 April 1958. The Rotodyne performed to expectations and set a world speed record in the convertiplane category, at 190.9 mph (307.2 km/h) on 5 January 1959, over a 60 mi (100 km) closed circuit. As well as being fast, the craft had a safety feature: it could hover with one engine shut down with its propeller
feathered
, and the prototype demonstrated several landings as an autogyro. The prototype was demonstrated several times at the Farnborough and Paris
air shows, regularly amazing onlookers. The Rotodyne's tip drive and unloaded rotor made its performance far better when compared to pure helicopters and other forms of "convertiplanes." The aircraft could be flown at 175 kn (324 km/h) and pulled into a steep climbing turn without demonstrating any adverse handling characteristics.
Throughout the world, interest was growing in the prospect of direct city-to-city transport. The market for the Rotodyne was that of a medium-haul "flying bus": It would take off vertically from an inner-city heliport
, with all lift
coming from the tip-jet driven rotor, and then would increase airspeed, eventually with all power from the engines being transferred to the propeller
s with the rotor autorotating
. In this mode, the collective pitch, and hence drag
, of the rotor could be reduced, as the wings would be taking as much as half of the craft's weight. The Rotodyne would then cruise at speeds of about 150 kn (280 km/h) to another city, e.g., London to Paris, where the rotor tip-jet system would be restarted for landing vertically in the city centre. When the Rotodyne landed and the rotor stopped moving, its blades drooped downward from the hub. To avoid striking the vertical stabilizer
s on start-up, the tips of these fins were angled down to the horizontal. They were raised once the rotor had spun up.
British European Airways
(BEA) announced that it was interested in the purchase of six aircraft, with a possibility of up to 20. The Royal Air Force
ordered 12 military transport versions. New York Airways
signed a letter of intent for the purchase of five with an option on more albeit with qualifications. The U.S. Army
was interested in buying 200 of the Type Y Rotodyne to be manufactured by Fairey's U.S. licensee, Kaman Helicopters
in Bloomfield, Connecticut. Government funding was secured again on the proviso that firm orders would be gained from BEA. The civilian orders were dependent on the noise issues being satisfactorily met.
, then the helicopter division of Bristol
, and Saunders-Roe were incorporated with Westland
. The larger Rotodyne design could be developed to take 57 to 75 passengers which with the Rolls-Royce Tyne
turboprops (5,250 shp/3,910 kW) would have a cruising speed of 200 kn (370 km/h). It would be able to carry nearly 8 tons (7 tonnes) of freight and British Army
vehicles would fit into its fuselage. Government funding of some £5 million was promised. The expected order from the RAF did not appear — they had no particular interest in the design, with the issue of nuclear deterrence to the fore at the time. The Tyne engines were starting to appear underpowered for the larger design. Rolls-Royce were told that they would have to fund the engine development themselves.
However, the end came when the interest shown by BEA declined to order the Rotodyne due to tip-jet noise concerns and a request for a military order was also turned down. Funding for the Rotodyne was terminated in early 1962. The corporate management at Westland decided that further Rotodyne development towards production status was not worth the investment required. After the program was terminated, the Rotodyne, which was, after all, government property, was dismantled and largely destroyed in the same way as the Bristol Brabazon
.
with no complaints being registered. There was also a noise-reduction program in process which had managed to reduce the noise level from 113dB to the desired level of 96 dB from 600 ft (180 m) away, less than the noise made by a London Underground
train, and at the time of cancellation, silencers were under development, which would have reduced the noise even further. This effort, however, was insufficient for BEA who, as expressed by Chairman Sholto Douglas, "would not purchase an aircraft that could not be operated due to noise", and the airline refused to order the Rotodyne, which in turn led to the collapse of the project.
It is only relatively recently that interest has been re-established in direct city-to-city transport, with aircraft such as the Bell/Augusta BA609 and the Carter Copter. The 2010 Eurocopter X3
experimental helicopter shares the general configuration of the Rotodyne, but is much smaller. A number of innovative gyrodyne designs are still being considered for future development.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
compound gyroplane designed and built by Fairey Aviation
Fairey Aviation
The Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes in Greater London and Heaton Chapel and RAF Ringway in Greater Manchester...
and intended for commercial and military applications. A development of the earlier Gyrodyne which had established a world helicopter speed record, the Rotodyne featured a tip-jet
Tipjets
Tip jet refers to the jet nozzles located at the tip of some helicopter rotor blades. The objective is to spin the rotor, much like a Catherine wheel firework....
-powered rotor that burned a mixture of fuel and compressed air bled from two wing-mounted Napier Eland
Napier Eland
|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9-External links:*...
turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
s. The rotor was driven for vertical takeoffs, landings and hovering, as well as low-speed translational flight, and autorotated during cruise flight with all engine power applied to two propellers. Although promising in concept and successful in trials, the Rotodyne program was eventually cancelled when a combination of politics and lack of commercial orders arising from concerns over high levels of rotor tip-jet noise doomed the project.
Design and development
Fairey developed the Fairey FB-1 GyrodyneFairey FB-1 Gyrodyne
|-See also:-References:NotesBibliography* Charnov, Dr. Bruce H. Retrieved: 18 May 2007.* Green, William and Gerald Pollinger. The Observer's Book of Aircraft, 1958 edition...
, a unique aircraft in its own right that defined a third type of rotorcraft, including autogyro
Autogyro
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...
and helicopter. Having little in common with the later Rotodyne, it was characterised by its inventor, Dr. J.A.J. Bennett, formerly Chief Technical Officer of the pre-Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
Cierva Autogiro Company
Cierva Autogiro Company
The Cierva Autogiro Company was a British developer of autogyros established in 1926.It was set up to further the designs of Juan de la Cierva with the financial backing of James George Weir, a Scottish industrialist and aviator.-History:...
as an intermediate aircraft designed to combine the safety and simplicity of the autogyro with hovering performance. Its rotor was driven in all phases of flight with collective pitch being an automatic function of shaft torque, with a side-mounted propeller providing both thrust for forward flight and rotor torque correction. The FB-1 set a world airspeed record in 1948, but a fatal accident due to poor machining of a rotor blade flapping link retaining nut terminated development of the pure gyrodyne. The second FB-1 was modified to investigate a tip-jet driven rotor with propulsion provided by propellers mounted at the tip of each stub wing. This was renamed the Jet Gyrodyne
Fairey Jet Gyrodyne
|-See also:-Bibliography:* Charnov, Dr. Bruce H. The Fairey Rotodyne: An Idea Whose Time Has Come – Again? Retrieved: 18 May 2007.* Green, William and Pollinger, Gerald...
, which despite its name, was a compound autogyro.
Fairey put forward their various designs for the proposed BEA Bus, which were revised over the years, and received government funding. However, getting access to engines proved to be difficult, with first Rolls-Royce
Rolls-Royce Limited
Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....
then Armstrong Siddeley
Armstrong Siddeley
Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury motor cars and aircraft engines.-Siddeley Autocars:...
claiming lack of resources. The Ministry of Supply
Ministry of Supply
The Ministry of Supply was a department of the UK Government formed in 1939 to co-ordinate the supply of equipment to all three British armed forces, headed by the Minister of Supply. There was, however, a separate ministry responsible for aircraft production and the Admiralty retained...
contracted in 1953 for the building of the prototype (serial number
United Kingdom military aircraft serials
In the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry , and its successor the Ministry of Defence , is used for aircraft operated by the Royal Air Force , Fleet...
XE521).
With a view to an aircraft that would meet regulatory approval in the shortest time, Fairey's designers worked to meet the Civil Airworthiness requirements for both helicopters and similar sized twin engined aircraft. A one-sixth scale rotorless model was extensively wind-tunnel tested for fixed-wing performance. A smaller (1/15th-scale) model with powered rotot was used for downwash investigations.
The Rotodyne had a large, four-bladed rotor
Helicopter rotor
A helicopter main rotor or rotor system is a type of fan that is used to generate both the aerodynamic lift force that supports the weight of the helicopter, and thrust which counteracts aerodynamic drag in forward flight...
and two Napier
Napier & Son
D. Napier & Son Limited was a British engine and pre-Great War automobile manufacturer and one of the most important aircraft engine manufacturers in the early to mid-20th century...
Eland
Napier Eland
|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9-External links:*...
N.E.L.3 turboprops, one mounted under each of the fixed wings.
For takeoff and landing, the rotor was driven by tip-jets. The air was produced by compressors driven through a clutch off the main engines. This was fed through ducting in the leading edge of the wings and up to the rotor head. Each engine supplied air for a pair of opposite rotors; the compressed air was mixed with fuel and burned. As a torqueless rotor system, no anti-torque correction system was required, though propeller pitch was controlled by the rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
pedals for low-speed yaw control. The propellers provided thrust for translational flight while the rotor autorotated. The cockpit controls included a cyclic and collective pitch lever, as in a conventional helicopter.
The rotor blades were a symmetrical aerofoil around a load-bearing spar. The aerofoil was made of steel and light alloy to because of centre of gravity concerns. Equally the spar was formed from a thick machined steel block to the fore and a lighter thinner section formed from folded and rivetted steel to the rear. The compressed air was channeled through three steel tubes within the blade. The tip jet combustion chambers were made from Nimonic 80
Nimonic
Nimonic is a registered trademark of Special Metals Corporation that refers to a family of nickel-based superalloys. Nimonic alloys typically consist of more than 50% nickel and 20% chromium with additives such as titanium and aluminium. The main use is in gas turbine components and extremely high...
with liners made from Nimonic 75.
While the prototype was being built, funding for the programme reached a crisis. Cuts in defence spending led the Ministry of Defence
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....
to withdraw support, pushing the burden of the costs onto any possible civilian customer. The Government agreed to continued funding only if, among other qualifications, Fairey and Napier (through their parent English Electric
English Electric
English Electric was a British industrial manufacturer. Founded in 1918, it initially specialised in industrial electric motors and transformers...
) contributed to development costs of the Rotodyne and the Eland engine respectively.
Testing and evaluation
Hiller Aircraft
Hiller Aircraft Company was founded in 1942 as Hiller Industries by Stanley Hiller to develop helicopters.- History :Stanley Hiller, then seventeen, established the first helicopter factory on the West Coast of the United States, located in Berkeley, California, in 1942, under the name "Hiller...
in California, the prototype, its development assumed by Dr. George S. Hislop, made its first flight on 6 November 1957 piloted by Chief Helicopter Test Pilot Squadron Leader
Squadron Leader
Squadron Leader is a commissioned rank in the Royal Air Force and the air forces of many countries which have historical British influence. It is also sometimes used as the English translation of an equivalent rank in countries which have a non-English air force-specific rank structure. In these...
W. Ron Gellatly and Assistant Chief Helicopter Test Pilot Lieutenant Commander
Lieutenant Commander
Lieutenant Commander is a commissioned officer rank in many navies. The rank is superior to a lieutenant and subordinate to a commander...
John G.P. Morton as Second Pilot.
The first successful transition from vertical to horizontal and back to vertical flight was achieved on 10 April 1958. The Rotodyne performed to expectations and set a world speed record in the convertiplane category, at 190.9 mph (307.2 km/h) on 5 January 1959, over a 60 mi (100 km) closed circuit. As well as being fast, the craft had a safety feature: it could hover with one engine shut down with its propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
feathered
Feather (disambiguation)
Feathers are epidermal growths which form an outer covering on birds and some dinosaurs.Feather may also refer to:- Science and technology :*Feather, an incision in diamonds affecting diamond clarity...
, and the prototype demonstrated several landings as an autogyro. The prototype was demonstrated several times at the Farnborough and Paris
Paris Air Show
The Paris Air Show is the world's oldest and largest air show. Established in 1909, it is currently held every odd year at Le Bourget Airport in north Paris, France...
air shows, regularly amazing onlookers. The Rotodyne's tip drive and unloaded rotor made its performance far better when compared to pure helicopters and other forms of "convertiplanes." The aircraft could be flown at 175 kn (324 km/h) and pulled into a steep climbing turn without demonstrating any adverse handling characteristics.
Throughout the world, interest was growing in the prospect of direct city-to-city transport. The market for the Rotodyne was that of a medium-haul "flying bus": It would take off vertically from an inner-city heliport
Heliport
A heliport is a small airport suitable only for use by helicopters. Heliports typically contain one or more helipads and may have limited facilities such as fuel, lighting, a windsock, or even hangars...
, with all lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
coming from the tip-jet driven rotor, and then would increase airspeed, eventually with all power from the engines being transferred to the propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
s with the rotor autorotating
Autorotation
In aviation, autorotation refers to processes in both fixed-wing and rotary-wing aircraft. The term means significantly different things in each context....
. In this mode, the collective pitch, and hence drag
Drag (physics)
In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...
, of the rotor could be reduced, as the wings would be taking as much as half of the craft's weight. The Rotodyne would then cruise at speeds of about 150 kn (280 km/h) to another city, e.g., London to Paris, where the rotor tip-jet system would be restarted for landing vertically in the city centre. When the Rotodyne landed and the rotor stopped moving, its blades drooped downward from the hub. To avoid striking the vertical stabilizer
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...
s on start-up, the tips of these fins were angled down to the horizontal. They were raised once the rotor had spun up.
British European Airways
British European Airways
British European Airways or British European Airways Corporation was a British airline which existed from 1946 until 1974. The airline operated European and North African routes from airports around the United Kingdom...
(BEA) announced that it was interested in the purchase of six aircraft, with a possibility of up to 20. The Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
ordered 12 military transport versions. New York Airways
New York Airways
New York Airways was a helicopter airline in the New York City area. Founded in 1949 as a mail and cargo carrier, on July 9, 1953 it became the first scheduled helicopter airline to carry passengers in the United States...
signed a letter of intent for the purchase of five with an option on more albeit with qualifications. The U.S. Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
was interested in buying 200 of the Type Y Rotodyne to be manufactured by Fairey's U.S. licensee, Kaman Helicopters
Kaman Aircraft
Kaman Aircraft is a U.S. aerospace company, with headquarters in Bloomfield, Connecticut. It was founded in 1945 by Charles Kaman. During the first ten years the company operated exclusively as a designer and manufacturer of several helicopters that set world records and achieved many aviation...
in Bloomfield, Connecticut. Government funding was secured again on the proviso that firm orders would be gained from BEA. The civilian orders were dependent on the noise issues being satisfactorily met.
Cancellation
In 1959, the British Government, seeking to cut costs, decreed that the number of aircraft firms be lowered and set forth their expectations for mergers in airframe and aero-engine companies. By delaying or withholding access to defence contracts the British firms could be forced into mergers. Fairey AviationFairey Aviation
The Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes in Greater London and Heaton Chapel and RAF Ringway in Greater Manchester...
, then the helicopter division of Bristol
Bristol Aeroplane Company
The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aero engines...
, and Saunders-Roe were incorporated with Westland
Westland Aircraft
Westland Aircraft was a British aircraft manufacturer located in Yeovil in Somerset. Formed as a separate company by separation from Petters Ltd just before the start of the Second World War, Westland had been building aircraft since 1915...
. The larger Rotodyne design could be developed to take 57 to 75 passengers which with the Rolls-Royce Tyne
Rolls-Royce Tyne
|-See also:...
turboprops (5,250 shp/3,910 kW) would have a cruising speed of 200 kn (370 km/h). It would be able to carry nearly 8 tons (7 tonnes) of freight and British Army
British Army
The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...
vehicles would fit into its fuselage. Government funding of some £5 million was promised. The expected order from the RAF did not appear — they had no particular interest in the design, with the issue of nuclear deterrence to the fore at the time. The Tyne engines were starting to appear underpowered for the larger design. Rolls-Royce were told that they would have to fund the engine development themselves.
However, the end came when the interest shown by BEA declined to order the Rotodyne due to tip-jet noise concerns and a request for a military order was also turned down. Funding for the Rotodyne was terminated in early 1962. The corporate management at Westland decided that further Rotodyne development towards production status was not worth the investment required. After the program was terminated, the Rotodyne, which was, after all, government property, was dismantled and largely destroyed in the same way as the Bristol Brabazon
Bristol Brabazon
The Bristol Type 167 Brabazon was a large propeller-driven airliner, designed by the Bristol Aeroplane Company to fly transatlantic routes from the United Kingdom to the United States. The prototype was delivered in 1949, only to prove a commercial failure when airlines felt the airliner was too...
.
Analysis
The one great criticism of the Rotodyne was the noise the tip jets made; however, the jets were only run at full power for a matter of minutes during departure and landing and, indeed, the test pilot Ron Gellatly made two flights over central London and several landings and departures at Battersea HeliportLondon Heliport
London Heliport at Battersea, London is the capital's main and busiest heliport. The facility is located on the south bank of the River Thames, southwest of Westminster Bridge and the Palace of Westminster, between Wandsworth Bridge and Battersea Railway Bridge.The nearest railway station is...
with no complaints being registered. There was also a noise-reduction program in process which had managed to reduce the noise level from 113dB to the desired level of 96 dB from 600 ft (180 m) away, less than the noise made by a London Underground
London Underground
The London Underground is a rapid transit system serving a large part of Greater London and some parts of Buckinghamshire, Hertfordshire and Essex in England...
train, and at the time of cancellation, silencers were under development, which would have reduced the noise even further. This effort, however, was insufficient for BEA who, as expressed by Chairman Sholto Douglas, "would not purchase an aircraft that could not be operated due to noise", and the airline refused to order the Rotodyne, which in turn led to the collapse of the project.
It is only relatively recently that interest has been re-established in direct city-to-city transport, with aircraft such as the Bell/Augusta BA609 and the Carter Copter. The 2010 Eurocopter X3
Eurocopter X3
|-See also:-External links:* * * * * * *...
experimental helicopter shares the general configuration of the Rotodyne, but is much smaller. A number of innovative gyrodyne designs are still being considered for future development.
Specifications (Rotodyne "Y")