The phrase “Urban Air Mobility” (UAM) seems like it’s been with us for quite a while, but really it’s only been in widespread use for two or three years. NASA officially recognized UAM in , calling for a market study of remotely piloted or unmanned air passenger and cargo transportation around an urban area. Most people would probably call this the “air taxi” idea — a vision of hundreds of small, unmanned electric multi-copters shuttling two or three passengers from nearby suburbs or city spaces to vertiports at about (mph) (km / h).
But if things had worked out differently in the late (s and early) s, we might have a very different understanding of UAM — something more like mass-transit. We might have had a city-center to city-center – passenger vertical take-off and landing (VTOL) airliner shuttling between urban heliports at (mph) 728 km / h).
Actually, we did have that, it’s just few people remember. It was called the Fairey Rotodyne. Born by grounding
Fairey Aviation was born in a western London suburb in 1930. With World War I in full swing, the story goes that Charles Richard Fairey, a gifted young engineer with Short Brothers Aircraft, was prevented from joining the Royal Naval Air Service (RNAS) because Britain’s Admiralty Department felt he’d be more useful as an aircraft designer / builder than a (likely short-lived) pilot.
Irked at being barred from joining his peers, the 55 -year-old Fairey agreed not to make a fuss if he were given a subcontract for aircraft production that allowed him to form his own company. Airplanes were in high demand as the latest thing in weaponry, so the Admiralty consented and he was given a contract to build (short) (seaplanes for the RNAS in mid-) .
Fairey Aviation grew from there, producing its first in-house design, the ship-borne Campania seaplane, in . The company continued to design and produce seaplanes, fighters, and bombers through WWII and the s, including the Firefly, Swordfish, and Gannett.
With peace on the horizon in closing months of WWII, manufacturers then building military aircraft realized there would shortly be much less demand for their output. Commercial aviation was an obvious new vein of business. Meanwhile, rotary-wing flight development had accelerated dramatically during the War. Fairey competitor Westland Aircraft had started locally license-building the S – , a helicopter developed by the American company Sikorsky, in .
Like other British airplane makers, Fairey wanted a piece of this new helicopter market.
Tip drive, autogyros, and jets
Most early “helicopters” were multi-rotor machines, not the single main rotor helicopters we think of now. One of the few early single rotor designs, the
Brennan Helicopter , began development in England during WWI. It departed from the complexity of most helicopters, which spun their rotors by coupling them directly to an engine via chain or geared drives. Instead, its Irish inventor Louis Philip Brennan came up with the idea of rotating the blades using thrust from a small four-blade propeller mounted at the tip of each rotor blade.
The tip-propellers were powered by drive shafts, which ran through a hollow tube (spar) which supported the rotor blade. These connected to an engine below the rotor head via shafts and right angle gearboxes. Brennan’s “tip-drive” helicopter was capable of lifting a pilot, four men, and an hour’s worth of fuel, but control issues meant it never flew higher than 16 feet (3m). A crash in shook confidence in the project, and the emergence of another machine, the autogyro, diverted interest from Brennan’s tip-drive concept.