The Hiller Rotorcycle - An Engineer's Aspect


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Monday, November 12, 2012

The Hiller Rotorcycle


According to The Smithsonian National Air and Space Museum, "In 1953, Hiller Helicopters developed the Rotorcycle to meet a U. S. Marine Corps requirement for a single-person collapsible helicopter that could support special operations missions or be air-dropped to pilots trapped behind enemy lines. Hiller built the prototype, and the British firm, Saunders-Roe built ten production models, including the five YROE-1s requested by the Marine Corps. The first flight of a Rotorcycle occurred in 1956."

Image: Artist Rendering of Military Vision for the Hiller Rotorcycle.
Source: Tales of Future Past

Image: One of the five YROE-1 Rotorcycles requested by the Marine Corps.
Source: The Smithsonian National Air and Space Museum

The announcement of the contract award was made in 1954. Many newspapers around the country ran the story. Following is one those accounts:

The San Mateo Times, San Mateo, California, USA, December 8, 1954, Page 12.

Helicopter Firm
Gets New Contract

EAST PALO ALTO, Dec. 8--Hiller Helicopters of East Palo Alto was one of two firms being awarded a contract by the navy to design and build a one-man portable helicopter. The contract is for more than $200,000.

The type of helicopter to be built will be for future use by the marine corps for observation liaison.

Eighteen manufacturers entered the competition and submitted over thirty separate designs for consideration by the bureau of aeronautics.

Propulsion for both rotorcycle designs accepted is a Nelson four-cylinder opposed, two-cycle, air-cooled gasoline engine manufactured by Barmotive Products, Inc., San Leandro.

The Hiller rotorcycle designated XROE-1 is a single two-blade rotor with a small tail rotor.


Shortly thereafter, late in 1954, work on the Hiller Rotorcycle began.

The Debut

In January of 1957, newspapers announced the debut of the new Hiller Rotorcycle:

The Daily Independent, Monessen, Pennsylvania, Friday, January 11, 1957, Page 10.

Collapsible Helicopter

PALO ALTO, Calif. (UP)--The Navy has unveiled a 250-pound collapsible, one-man helicopter which it described as the latest thing in front liaison craft.

The device, called the "Rotocycle," was developed by the Hiller Helicopter Corp. for tactical use by the Marine Corps. A Hiller spokesman said it comes as close to the idea of a "strap-on-back" helicopter as has yet been developed.

The craft is powered by a 4-cylinder opposed, air-cooled engine mounted on the pilot's back. A single rotor 18 feet in diameter provides the lift and a small tail rotor compensates for the torque.

Performance data was not disclosed.

The Navy said the Marine Corps would use the Rotocycle for observation, liaison and small unit tactical maneuvers.

Image: Hiller Helicopter Press Photo, January 10, 1957.
Caption: UNFOLD IT, FLY AWAY--While the Navy's one-man collapsible helicopter hovers overhead in flight, a marine officer looks at a collapsed version of the aircraft now being built by Hiller Helicopters at Palo Alto, Calif. The Navy calls the machine "a one-man collapsible motorcycle" and says it is designed for easy transportation or parachute drop. It weighs less than 250 pounds. --AP Wirephoto.

The Rotorcycle demonstrations sparked public interest and the question of personal Rotorcycles arose.

The Billings Gazette, Billings, Montana, Tuesday Morning, April 30, 1957, Page 1.

Commuters Show
Interest in New
Aerial Puddle-Jumper

PALO ALTO, CALIF. (U.P.)--Hiller Helicopter Co. Monday demonstrated a commuter's dream--a one-man aerial puddle-jumper called the XROE-1 "Rotorcycle."

But President Stanley Hiller Jr. said it will be a long time before the average citizen may own one. The rotorcycle was designed for the U.S. Navy which wants them for rescue, liaison and troop movement. And the Navy will take the whole production for some time to come.

Hiller said when the first picture of the rotorcycle was released last January, his firm received inquiries from all over the world as to when they would be available for private owners.


Image: Press Photo of US Marine Corps Demonstration of the Hiller Rotorcycle (1957).


"Because its manufacturing capability was dedicated to the production and development of other aircraft, Hiller could not afford to produce the small one-seater. For this reasons British manufacturer, Saunders-Roe Ltd based in Eastleight, built the five Marine Corps Rotorcycles under license along with an additional five aircraft for the European market ( by Mario Bazzani)."

The San Mateo Times, San Mateo, California, Friday, November 21, 1958, Page 15.

Saunders-Roe to Build Hiller Copter in England

Saunders-Roe, Ltd. of Southampton, England, will produce under license the one-man "Rotorcycle" helicopter of Hiller Aircraft corporation, it was revealed today by Hiller Executive Vice President Edward T. Bolton. Bolton stated that Hiller's European distributor, Commandant Henry Boris of "Helicop-Air", Paris, is the licensee, and that he has sub-licensed Saunders-Roe to build the Rotorcycle.

The large English firm will manufacture an initial production quantity of the tiny helicopters, five of which will be for U.S. Marine Corps field evaluation. An undisclosed additional quantity will be included for demonstration, and for evaluation by European military agencies.

Saunders-Roe is one of Europe's oldest and largest manufacturing complexes, known for its giant flying boats, sea-based fighters, helicopters and high speed jet and rocket aircraft as well as patrol-torpedo boats, landing craft, electronic equipment, trucks and many other industrial items.

The Saunders-Roe Helicopter division in Southampton is under the direction of General Manager Hugh Gordon. The division is currently producing the two-place "Skeeter" helicopter and has recently introduced a new five-place turbine-powered P .531 helicopter. The license negotiations with Saunders-Roe and Helicop-Air have been carried out by Hiller Vice President-European Operations A. J. M. Chadwick.


Technical Information

Image: Details of the Hiller Rotorcycle.
Source: Tales of Future Past

The Rotorcycle flight performance under International Standard Atmosphere (ISA) conditions are reported as follows (engine Nelson H-63B):

                 Take-off weight                                         225 kg                 251 kg
                 Cruise speed                                            84 km/h               79 km/h
                 Hovering IGE                                          2'800 m               1'680 m
                 Hovering OGE                                        1'950 m                  795 m
                 Service ceiling                                         4'010 m                3'650 m
                 Initial rate of climb at sea level            207 m/min            100 m/min
                 Max. rate of climb at sea level             354 m/min            280 m/min
                 Maximum speed at sea level (Vne) was di 104 km/h (56 kts).
                 (Source: by Mario Bazzani)

Following are the Rotorcycle's dimensions:

                Rotor Diameter:                                    5.64 m (18 ft 6 in)
                Length:                                                 3.81 m (12 ft 6 in)
                Height:                                                  2.29 m (7 ft 6 in)
                Weight, Empty:                                     140 kg (309 lb)
                Weight, Gross:                                      255 kg (562 lb)
                (Source: Smithsonian National Air and Space Museum)

The Outcome

The Smithsonian claims that "The Rotorcycle was so stable a non-pilot could fly it after only eight hours of instruction. However, The Marine Corps did not accept the YROE-1 for military service because of its slow speed of 84 kph (52 mph), its minimal range of 64 km (40 miles), its vulnerability to small-arms fire and the lack of visual references on the structure, which could cause the pilot to experience spatial disorientation at all but very low altitudes."

This video, found on the British Pathe website, shows the Hiller Rotorcycle in flight: