Cessna CH-1
Encyclopedia
The Cessna CH-1 is the only helicopter
ever built by the Cessna Aircraft Company
. It was the first helicopter to land on the summit of Pike's Peak and the last piston-engined helicopter to set the helicopter altitude record. The CH-1 had a single, two-bladed main rotor, and a front-mounted reciprocating engine which gave the aircraft a stable center-of-gravity (CG). Its semi-monocoque
airframe greatly resembles its light airplane siblings built by Cessna. The CH-1 was named Skyhook for the civil market, similar to the marketing names used in the Cessna single engine airplane line, such as Skyhawk
, Skylane
and Skywagon
. The United States Army
designated the CH-1C as the YH-41 Seneca. While the CH-1 achieved several helicopter "firsts" and set a world record, it never became a commercial or military success.
on 14 January 1952 through a stock swap with Seibel investors. All equipment from the Seibel Helicopter Company, including the Seibel S-4B, was moved to Cessna's Pawnee Plant in Wichita and work began on the CH-1 design during the summer of 1952. Charles Seibel, who became the new Helicopter Division's chief engineer as part of the acquisition, believed that the S-4B with a Cessna body would make an excellent helicopter. Cessna pilots test flew Seibel's S-4B for several months to familiarize the engineers with helicopters, and then it was scrapped.
A quarter-size wind tunnel model of the CH-1 was created and tests were conducted at Wichita State University. The first full-size machine did not have an enclosed fuselage or cowling, nor a horizontal stabilizer. This test bed skeleton, referred to as CH1-1, first hovered in July 1953, eventually making test flights as high as 10,000 feet (3,000 m). The actual prototype CH-1 was built based on modifications made to the test bed aircraft and this second ship made its first flight in 1954, at the Prospect plant.
On 9 June 1955, the CH-1 received CAA type-certificate 3H10. Originally certified as a two-place helicopter, stability problems at higher gross weights required additional engineering solutions. A larger, free-floating horizontal stabilizer was introduced. During forward flight, the stabilizer pivoted to a variable mechanical stop, which was linked to the fore and aft cyclic control, thereby altering the stabilizer angle of incidence during flight. Reworking the stabilizer permitted the addition of a second row of seating, and the four-place ship, designated the CH-1A, was certificated on 28 February 1956.
engine and other aerodynamic and structural changes in the possibility of eliciting a production contract. In spring 1956, the Army awarded Cessna with a US$1.1 million contract for 10 test aircraft, designated as the YH-41 Seneca. For marketing purposes, the CH-1A prototype (N5156) was painted in an olive drab Army scheme.
The CH-1 external design was created by Richard Ten Eyck, an industrial designer for Cessna. It was a low profile streamlined aircraft-style body, featuring the engine in front and cabin seating behind the powerplant. The forward engine location provided "ease of access,...efficient cooling, and frees the center of gravity behind the cockpit for use in disposable load," but also presented a problem for how to vent the exhaust which would prove to be a problem throughout the aircraft's life. Additionally, the tail boom size, resulting from the airplane-style fuselage, created aerodynamic problems in hover and forward flight that would have to be solved by later aerodynamic structural changes.
six-cylinder engine, producing 260 hp (190 kW) at 3,200 rpm. The engine's supercharger and cooling fans were driven by belts. Cessna had a long relationship with Continental who provided engines for the company's light airplanes, but the use of the Continental engine in a helicopter was as much of a test for the engine company, as Cessna's foray into the helicopter market, itself. This was especially true when considered that most other light helicopter manufacturers were using Franklin
and Lycoming
engines.
, at an altitude of 14110 feet (4,300.7 m) on 15 September 1955, it had a higher cruise speed than comparable machines, and a CH-1B, modified with an FSO-526-2X engine, set an official FAI
world altitude record for helicopters of 29,777 feetCessna's calibrated instrumentation showed 30,355 feet. on December 28, 1957, while being piloted by Army Captain James E. Bowman. The previous record had been set by a turbine powered Aérospatiale Alouette II and was later broken by another Alouette II, but the record set by the CH-1B remains the highest altitude ever achieved by a piston-powered helicopter. The CH-1C was the first helicopter to receive IFR certification by the FAA
.
Production was ended in December 1962. The company indicated that this was due to the civil aviation market not being ready for this type of aircraft, although CH-1 owner Rex Trailer
claims that it was due to catastrophic transmission failures.
CH-1:The prototype CH-1 was powered by a Continental FSO-470 engine with a 2-place cabin.
CH-1A:Four-seat version of the CH-1 created by solving stability problems presented by the tail boom.
CH-1B:1955 changes to secure an Army contract. Continental FSO-526 engine producing 270 hp (200 kW) at 3000 rpm, with a gear-driven supercharger and horizontal cooling fan. An automatic collective pitch reducer lowered the collective pitch in the event of an engine failure.
YH-41A:Ten CH-1Bs purchased by the United States Army for evaluation against possible future production contract.
CH-1C:
UH-41A:15 CH-1C aircraft purchased by the United States Government for its Military Assistance Program (MAP) to foreign countries.
CH-4:Cessna's entry for the U.S. Army's Light Observation Helicopter
program, it was a CH-1C powered by an Allison Model 250 engine mounted behind the rear passenger seat.
CH-1D:CH-1C modified with Continental's "Whirlaway" engine.
, Alabama has a YH-41A Seneca prototype (serial number 56-4244) as a part of its collection, although it is not currently on display.
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
ever built by the Cessna Aircraft Company
Cessna
The Cessna Aircraft Company is an airplane manufacturing corporation headquartered in Wichita, Kansas, USA. Their main products are general aviation aircraft. Although they are the most well known for their small, piston-powered aircraft, they also produce business jets. The company is a subsidiary...
. It was the first helicopter to land on the summit of Pike's Peak and the last piston-engined helicopter to set the helicopter altitude record. The CH-1 had a single, two-bladed main rotor, and a front-mounted reciprocating engine which gave the aircraft a stable center-of-gravity (CG). Its semi-monocoque
Monocoque
Monocoque is a construction technique that supports structural load by using an object's external skin, as opposed to using an internal frame or truss that is then covered with a non-load-bearing skin or coachwork...
airframe greatly resembles its light airplane siblings built by Cessna. The CH-1 was named Skyhook for the civil market, similar to the marketing names used in the Cessna single engine airplane line, such as Skyhawk
Cessna 172
The Cessna 172 Skyhawk is a four-seat, single-engine, high-wing fixed-wing aircraft. First flown in 1955 and still in production, more Cessna 172s have been built than any other aircraft.-Design and development:...
, Skylane
Cessna 182
The Cessna 182 Skylane is an American four-seat, single-engine, light airplane, built by Cessna of Wichita, Kansas. It has the option of adding two child seats, installed in the baggage area....
and Skywagon
Cessna 185
-Specification for differing configurations:-References:* Jan Churchill, Hit My Smoke: Forward Air Controllers in Southeast Asia, Sunflower University Press, Manhattan KS, ISBN 0-89745-215-1...
. The United States 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...
designated the CH-1C as the YH-41 Seneca. While the CH-1 achieved several helicopter "firsts" and set a world record, it never became a commercial or military success.
Development
Cessna Aircraft Company acquired the Seibel Helicopter Company of Wichita, KansasWichita, Kansas
Wichita is the largest city in the U.S. state of Kansas.As of the 2010 census, the city population was 382,368. Located in south-central Kansas on the Arkansas River, Wichita is the county seat of Sedgwick County and the principal city of the Wichita metropolitan area...
on 14 January 1952 through a stock swap with Seibel investors. All equipment from the Seibel Helicopter Company, including the Seibel S-4B, was moved to Cessna's Pawnee Plant in Wichita and work began on the CH-1 design during the summer of 1952. Charles Seibel, who became the new Helicopter Division's chief engineer as part of the acquisition, believed that the S-4B with a Cessna body would make an excellent helicopter. Cessna pilots test flew Seibel's S-4B for several months to familiarize the engineers with helicopters, and then it was scrapped.
A quarter-size wind tunnel model of the CH-1 was created and tests were conducted at Wichita State University. The first full-size machine did not have an enclosed fuselage or cowling, nor a horizontal stabilizer. This test bed skeleton, referred to as CH1-1, first hovered in July 1953, eventually making test flights as high as 10,000 feet (3,000 m). The actual prototype CH-1 was built based on modifications made to the test bed aircraft and this second ship made its first flight in 1954, at the Prospect plant.
On 9 June 1955, the CH-1 received CAA type-certificate 3H10. Originally certified as a two-place helicopter, stability problems at higher gross weights required additional engineering solutions. A larger, free-floating horizontal stabilizer was introduced. During forward flight, the stabilizer pivoted to a variable mechanical stop, which was linked to the fore and aft cyclic control, thereby altering the stabilizer angle of incidence during flight. Reworking the stabilizer permitted the addition of a second row of seating, and the four-place ship, designated the CH-1A, was certificated on 28 February 1956.
CH-1B
In December 1955, Cessna was awaiting a contract to produce a limited number of CH-1s for evaluation by the Army. In preparation for the contract, Cessna began modifying the CH-1A with a Continental FSO-526Continental O-520
-External links:...
engine and other aerodynamic and structural changes in the possibility of eliciting a production contract. In spring 1956, the Army awarded Cessna with a US$1.1 million contract for 10 test aircraft, designated as the YH-41 Seneca. For marketing purposes, the CH-1A prototype (N5156) was painted in an olive drab Army scheme.
Design
The aircraft incorporated a unique L-section hinges to attach the main rotor blades to the hub in place of more conventional pitch change bearings.The CH-1 external design was created by Richard Ten Eyck, an industrial designer for Cessna. It was a low profile streamlined aircraft-style body, featuring the engine in front and cabin seating behind the powerplant. The forward engine location provided "ease of access,...efficient cooling, and frees the center of gravity behind the cockpit for use in disposable load," but also presented a problem for how to vent the exhaust which would prove to be a problem throughout the aircraft's life. Additionally, the tail boom size, resulting from the airplane-style fuselage, created aerodynamic problems in hover and forward flight that would have to be solved by later aerodynamic structural changes.
Engine
The prototype CH-1 was originally equipped with a supercharged Continental FSO-470Continental O-470
The Continental O-470 engine is a family of carbureted six-cylinder, horizontally opposed, air-cooled aircraft engines that was developed especially for use in light aircraft by Continental Motors. The family includes the E165, E185 and the E225 engines...
six-cylinder engine, producing 260 hp (190 kW) at 3,200 rpm. The engine's supercharger and cooling fans were driven by belts. Cessna had a long relationship with Continental who provided engines for the company's light airplanes, but the use of the Continental engine in a helicopter was as much of a test for the engine company, as Cessna's foray into the helicopter market, itself. This was especially true when considered that most other light helicopter manufacturers were using Franklin
Franklin Engine Company
The Franklin Engine Company was a manufacturer of aircraft engines, formed as the H. H. Franklin Co. in 1902, located in Syracuse, New York, United States. Barely surviving bankruptcy in 1933, the company was purchased by a group of ex-employees and renamed Aircooled Motors in 1937...
and Lycoming
Lycoming Engines
Lycoming Engines is a U.S. aircraft engine company, known primarily for its general aviation engines. For most of its history Lycoming has been part of the AVCO group as AVCO Lycoming. In 1987 AVCO was purchased by Textron to become Textron Lycoming...
engines.
Operational history
The CH-1 established many firsts. The CH-1A was the first helicopter to land on Pikes PeakPikes Peak
Pikes Peak is a mountain in the Front Range of the Rocky Mountains, west of Colorado Springs, Colorado, in El Paso County in the United States of America....
, at an altitude of 14110 feet (4,300.7 m) on 15 September 1955, it had a higher cruise speed than comparable machines, and a CH-1B, modified with an FSO-526-2X engine, set an official FAI
Fédération Aéronautique Internationale
The Fédération Aéronautique Internationale is the world governing body for air sports and aeronautics and astronautics world records. Its head office is in Lausanne, Switzerland. This includes man-carrying aerospace vehicles from balloons to spacecraft, and unmanned aerial vehicles...
world altitude record for helicopters of 29,777 feetCessna's calibrated instrumentation showed 30,355 feet. on December 28, 1957, while being piloted by Army Captain James E. Bowman. The previous record had been set by a turbine powered Aérospatiale Alouette II and was later broken by another Alouette II, but the record set by the CH-1B remains the highest altitude ever achieved by a piston-powered helicopter. The CH-1C was the first helicopter to receive IFR certification by the FAA
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
.
Production was ended in December 1962. The company indicated that this was due to the civil aviation market not being ready for this type of aircraft, although CH-1 owner Rex Trailer
Rex Trailer
Rex Trailer is a Boston, Massachusetts based television personality, broadcast pioneer, and Country and Western recording artist. He is best known as the host of the children's show Boomtown.-Early life:...
claims that it was due to catastrophic transmission failures.
Variants
CH1-1:test bed machine which did not have a skin, for initial hover and flight testing.CH-1:The prototype CH-1 was powered by a Continental FSO-470 engine with a 2-place cabin.
CH-1A:Four-seat version of the CH-1 created by solving stability problems presented by the tail boom.
CH-1B:1955 changes to secure an Army contract. Continental FSO-526 engine producing 270 hp (200 kW) at 3000 rpm, with a gear-driven supercharger and horizontal cooling fan. An automatic collective pitch reducer lowered the collective pitch in the event of an engine failure.
YH-41A:Ten CH-1Bs purchased by the United States Army for evaluation against possible future production contract.
CH-1C:
UH-41A:15 CH-1C aircraft purchased by the United States Government for its Military Assistance Program (MAP) to foreign countries.
CH-4:Cessna's entry for the U.S. Army's Light Observation Helicopter
Light Observation Helicopter
The Light Observation Helicopter program was a United States Army program to evaluate, develop and field a light scout helicopter to replace the Army's aging OH-13 Sioux. The program gained impetus with the advent of the Vietnam War and was aided by advances in helicopter technology, specifically...
program, it was a CH-1C powered by an Allison Model 250 engine mounted behind the rear passenger seat.
CH-1D:CH-1C modified with Continental's "Whirlaway" engine.
Operators
- Ecuadorian Air ForceEcuadorian Air ForceThe Ecuadorian Air Force is the Air arm of the Military of Ecuador and responsible for the protection of the Ecuadorian airspace.-Mission:To develop the military air wing, in order to execute institutional objectives which guarantee sovereignty and contribute towards the nation's security and...
- four UH-41A
- Iranian Army - five UH-41A, replaced by Bell 205 and Bell 206 aircraft.
- United States ArmyUnited States ArmyThe 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...
- ten YH-41As for evaluation.
Survivors
Approximately 50 machines were built before Cessna ended their venture into helicopters. Most of the aircraft built were bought back and scrapped by Cessna, and the type certificate was revoked, presumably to remove any liability to Cessna for continued operation of any copies they could not retrieve. However, the Army Aviation Museum at Fort RuckerFort Rucker
Fort Rucker is a U.S. Army post located mostly in Dale County, Alabama, United States. It was named for a Civil War officer, Confederate General Edmund Rucker. The post is the primary flight training base for Army Aviation and is home to the United States Army Aviation Center of Excellence and...
, Alabama has a YH-41A Seneca prototype (serial number 56-4244) as a part of its collection, although it is not currently on display.