Platt-Le Page XR-1
Encyclopedia
The Platt-LePage XR-1, also known by the company designation PL-3, was an early American twin-rotor helicopter
, built by the Platt-LePage Aircraft Company
of Eddystone, Pennsylvania
. The winner of a United States Army Air Force design competition held in early 1940, the XR-1 was the first helicopter tested by the USAAF, flying in 1941. The flight testing of the XR-1 proved troublesome, and although continued testing showed that the design had promise, other, improved helicopters were becoming available before the XR-1 was ready for service. As a result, the development of the aircraft was terminated in 1945.
s developed by Kellett and Pitcairn.
Following the selection of the Platt-LePage design in May 1940, a contract for the construction of a prototype and a static test airframe was issued in July of that year. The contract specified delivery of the flying prototype in January 1941, however the aircraft was not completed until three months later than the contract schedule, a delay that led to Sikorsky receiving Dorsey-Logan Act funding for development of its design, which became the XR-4.
In its design, the XR-1 bore a strong resemblance to the Focke-Wulf Fw 61
, a helicopter developed by Heinrich Focke in Germany that, flown by Hanna Reisch, had impressed Platt-LePage co-founder Wynn LePage during a tour of Europe. The XR-1 was powered by a Pratt & Whitney R-985
radial engine
, mounted in a buried installation within the fuselage. The aircraft had two, three-bladed rotors, mounted in a side-by-side arrangement on wing-like pylons. The pylons were aerodynamically designed to produce some lift
when in forwards flight, slightly unloading the rotors. The construction of the XR-1 was conventional by the standards of the time, with the aircraft's frame consisting of a steel-tube framework, which was covered with fabric. The XR-1 had tail surfaces similar to those of a conventional aircraft, and was equipped with a fixed, taildragger landing gear. The aircraft's wheels freely castered for easier maneuvering on the ground.
The cockpit of the XR-1 seated the aircraft's two crew members in a tandem arrangement, the pilot located ahead of the observer, and was extensively glazed to provide good visibility in the aircraft's intended observation and army co-operation role. During the development of the aircraft, Major General Robert M. Danford proposed to the War Department that the XR-1 be evaluated against the Stinson YO-54 and the Kellett YG-1B autogyro
.
issues with the airframe that made the XR-1 prone to pilot-induced oscillation
s. The aircraft was modified in an attempt to resolve these issues, and the Army modified Platt-LePage's contract to provide additional funding for improvements to the design, but despite this the XR-1's problems continued. In addition, the company's test pilot, Lou Leavitt, lacked confidence in the design, refusing to fly the aircraft to its full potential. The situation was only resolved when Colonel H. Franklin Gregory, director of rotor-wing projects for the Army Air Forces, flew the aircraft himself, reaching 100 mph (160.9 km/h) on his first flight in the aircraft.
With the worst of the aircraft's problems believed to have been resolved, the XR-1 was submitted for service testing by the Army Air Forces in 1943. During the course of the Army's evaluations, the XR-1's empennage failed during structural testing, the surfaces being strengthened as a result and testing, following the repairs, resuming in 1944. Despite the modifications to the design, however, the XR-1 still proved to be deficient in control authority. In July 1943, the XR-1 program suffered a setback when the aircraft crashed, seriously injuring test pilot Jim Ray, who had replaced Leavitt following the latter's dismissal from the company. The crash was caused by an inspector's error in leaving a suspect part on the aircraft, the rotor hub failing in flight as a result of the decision. The aircraft was repairable, but it would be a year before the XR-1 was ready to fly again.
Testing was, however, able to continue in the meantime, as Platt-LePage had re-negotiated the XR-1 contract to cover a second flight-test aircraft. Built to a revised and improved version of the XR-1's design and designated XR-1A, the second aircraft had flown for the first time in May 1943. The XR-1A featured a revised cockpit covering compared to that of the XR-1, with the area of glazing being increased for improved visibility, and the pilot and observer's positions being reversed, the pilot now seated in the rear cockpit. During flight testing the XR-1A was found superior in flight performance to the XR-1; however, the controls were still proving troublesome, although the worst of the bugs did seem to have been worked out.
Following a cross-country flight to Wright Field
in Ohio from Platt-LePage's Pennsylvania plant, testing of the XR-1A continued until a mechanical failure in the rotor hub led to a crash landing on 26 October 1944, the company deciding to sell the wreckage for scrap.
The XR-1, having been repaired in the meantime, was once again flying, and a contract had been awarded to Platt-Lepage for the construction of seven pre-production aircraft, to be built to an improved version of the XR-1A design, and designated YR-1A. Motivated by Congressional concerns about potential favouritism towards Sikorsky Aircraft
, which had in the meantime been given a contract for development of an improved version of their VS-300 experimental helicopter, the contract called for delivery of the first YR-1A to the Army in January 1945. However, due to continued financial and flight-testing problems, Platt-Lepage proved incapable of meeting this schedule.
Although the XR-1's problems seemed to be approaching resolution by late 1944, the protracted development of the aircraft meant that alternative, improved helicopters, such as Sikorsky's XR-4
, less expensive and more maneuverable than Platt-LePage's aircraft, were becoming available. In addition, even the XR-1A's improvements had failed to cure the aircraft of all of its control and vibration problems, and the AAF's Air Material Command considered the company "inept" in its work, applying a "hit-or-miss method" to research and development. As a result of this assessment, the Army's contracts with the company were universally cancelled in early April 1945.
Following the cancellation of the Army's contract, the XR-1 was returned to the company, Platt-LePage believing that the design had potential as a civilian aircraft. The planned civilian version, the PL-9, would have been an enlarged, twin-engined aircraft; however Platt-LePage was by now in serious financial difficulty following the cancellation of its Army contract, and in mid 1946 the XR-1's flight test program was concluded, the aircraft being retired to the Smithsonian Institution
.
In the meantime, the company's former test pilot, Lou Leavitt, had purchased the wreckage of the XR-1A at a price of 4 cents per pound. Leavitt had formed a new company, Helicopter Air Transport, intending to provide helicopter flight training in anticipation of a postwar aviation boom, and he returned the XR-1A to flying condition. The projected boom failed to materialise, however, and HAT quickly entered bankruptcy
, Leavitt selling the XR-1A to Frank Piasecki
, another former Platt-LePage employee who had now started his own helicopter company. Piasecki soon grounded the aircraft due to airworthiness concerns, and used the airframe in the development of the PA-2B, a planned tiltrotor
which failed to proceed beyond the mock-up stage.
's National Air and Space Museum
. The unrestored aircraft is stored at the Paul Garber Restoration and Storage Facility in "remarkable condition".
XR-1A
YR-1A
PL-4
Piasecki PA-2B
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...
, built by the Platt-LePage Aircraft Company
Platt-LePage Aircraft Company
The Platt-LePage Aircraft Company was a manufacturer of aircraft for the armed forces of the United States of America. Based in Eddystone, Pennsylvania, the company produced the first helicopter to be officially acquired by the United States Army Air Forces....
of Eddystone, Pennsylvania
Eddystone, Pennsylvania
Eddystone is a borough in Delaware County, Pennsylvania, United States. The population was 2,442 at the 2000 census.-Early history:The area at the mouth of Ridley Creek was first called "Tequirassy" by Native Americans. The land was owned by Olof Persson Stille, one of the early settlers from New...
. The winner of a United States Army Air Force design competition held in early 1940, the XR-1 was the first helicopter tested by the USAAF, flying in 1941. The flight testing of the XR-1 proved troublesome, and although continued testing showed that the design had promise, other, improved helicopters were becoming available before the XR-1 was ready for service. As a result, the development of the aircraft was terminated in 1945.
Design and development
Developed during 1939 from an earlier, unsuccessful design, the PL-1, the Platt-LePage Model PL-3 was the winner of a 1940 design competition, held under the terms of the Dorsey-Logan Act, for the supply of a helicopter design to the United States Army Air Force. Platt-LePage's submission was judged by the Army to be superior to its competitors, which included a helicopter submitted by Vought-Sikorsky, and autogyroAutogyro
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...
s developed by Kellett and Pitcairn.
Following the selection of the Platt-LePage design in May 1940, a contract for the construction of a prototype and a static test airframe was issued in July of that year. The contract specified delivery of the flying prototype in January 1941, however the aircraft was not completed until three months later than the contract schedule, a delay that led to Sikorsky receiving Dorsey-Logan Act funding for development of its design, which became the XR-4.
In its design, the XR-1 bore a strong resemblance to the Focke-Wulf Fw 61
Focke-Wulf Fw 61
|-See also:-References:NotesBibliography* Coates, Steve and Jean-Christophe Carbonel. Helicopters of the Third Reich. Crowborough, UK: Classic Publications Ltd., 2002. ISBN 1-903223-24-5....
, a helicopter developed by Heinrich Focke in Germany that, flown by Hanna Reisch, had impressed Platt-LePage co-founder Wynn LePage during a tour of Europe. The XR-1 was powered by a Pratt & Whitney R-985
Pratt & Whitney R-985
The Pratt & Whitney R-985 Wasp Junior is a series of nine-cylinder air-cooled radial aircraft engines built by the Pratt & Whitney Aircraft Company from the 1930s to the 1950s. These engines have a displacement of ; initial versions produced , while the most widely used versions produce...
radial engine
Radial engine
The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel...
, mounted in a buried installation within the fuselage. The aircraft had two, three-bladed rotors, mounted in a side-by-side arrangement on wing-like pylons. The pylons were aerodynamically designed to produce some 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...
when in forwards flight, slightly unloading the rotors. The construction of the XR-1 was conventional by the standards of the time, with the aircraft's frame consisting of a steel-tube framework, which was covered with fabric. The XR-1 had tail surfaces similar to those of a conventional aircraft, and was equipped with a fixed, taildragger landing gear. The aircraft's wheels freely castered for easier maneuvering on the ground.
The cockpit of the XR-1 seated the aircraft's two crew members in a tandem arrangement, the pilot located ahead of the observer, and was extensively glazed to provide good visibility in the aircraft's intended observation and army co-operation role. During the development of the aircraft, Major General Robert M. Danford proposed to the War Department that the XR-1 be evaluated against the Stinson YO-54 and the Kellett YG-1B 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...
.
Operational history
Following several months of ground testing, the XR-1 conducted its maiden flight on May 12, 1941, although the aircraft was restrained by a tether for its early flights. On June 23 the aircraft conducted its first free flight, albeit remaining within a few feet of the ground. As flight testing continued and the aircraft's performance envelope was expanded, the XR-1's quickly proved troublesome, the testing showing a variety of troubles with the design. These included issues with the aircraft's controls, insufficient control authority being present, and in addition there were resonanceResonance
In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies...
issues with the airframe that made the XR-1 prone to pilot-induced oscillation
Pilot-induced oscillation
Pilot-induced oscillations, as defined by MIL-HDBK-1797A, are sustained or uncontrollable oscillations resulting from efforts of the pilot to control the aircraft and occurs when the pilot of an aircraft inadvertently commands an often increasing series of corrections in opposite directions, each...
s. The aircraft was modified in an attempt to resolve these issues, and the Army modified Platt-LePage's contract to provide additional funding for improvements to the design, but despite this the XR-1's problems continued. In addition, the company's test pilot, Lou Leavitt, lacked confidence in the design, refusing to fly the aircraft to its full potential. The situation was only resolved when Colonel H. Franklin Gregory, director of rotor-wing projects for the Army Air Forces, flew the aircraft himself, reaching 100 mph (160.9 km/h) on his first flight in the aircraft.
With the worst of the aircraft's problems believed to have been resolved, the XR-1 was submitted for service testing by the Army Air Forces in 1943. During the course of the Army's evaluations, the XR-1's empennage failed during structural testing, the surfaces being strengthened as a result and testing, following the repairs, resuming in 1944. Despite the modifications to the design, however, the XR-1 still proved to be deficient in control authority. In July 1943, the XR-1 program suffered a setback when the aircraft crashed, seriously injuring test pilot Jim Ray, who had replaced Leavitt following the latter's dismissal from the company. The crash was caused by an inspector's error in leaving a suspect part on the aircraft, the rotor hub failing in flight as a result of the decision. The aircraft was repairable, but it would be a year before the XR-1 was ready to fly again.
Testing was, however, able to continue in the meantime, as Platt-LePage had re-negotiated the XR-1 contract to cover a second flight-test aircraft. Built to a revised and improved version of the XR-1's design and designated XR-1A, the second aircraft had flown for the first time in May 1943. The XR-1A featured a revised cockpit covering compared to that of the XR-1, with the area of glazing being increased for improved visibility, and the pilot and observer's positions being reversed, the pilot now seated in the rear cockpit. During flight testing the XR-1A was found superior in flight performance to the XR-1; however, the controls were still proving troublesome, although the worst of the bugs did seem to have been worked out.
Following a cross-country flight to Wright Field
Wright Field
Wright Field was an airfield of the United States Army Air Corps and Air Forces near Riverside, Ohio. From 1927 to 1947 it was the research and development center for the Air Corps, and during World War II a flight test center....
in Ohio from Platt-LePage's Pennsylvania plant, testing of the XR-1A continued until a mechanical failure in the rotor hub led to a crash landing on 26 October 1944, the company deciding to sell the wreckage for scrap.
The XR-1, having been repaired in the meantime, was once again flying, and a contract had been awarded to Platt-Lepage for the construction of seven pre-production aircraft, to be built to an improved version of the XR-1A design, and designated YR-1A. Motivated by Congressional concerns about potential favouritism towards Sikorsky Aircraft
Sikorsky Aircraft
The Sikorsky Aircraft Corporation is an American aircraft manufacturer based in Stratford, Connecticut. Its parent company is United Technologies Corporation.-History:...
, which had in the meantime been given a contract for development of an improved version of their VS-300 experimental helicopter, the contract called for delivery of the first YR-1A to the Army in January 1945. However, due to continued financial and flight-testing problems, Platt-Lepage proved incapable of meeting this schedule.
Although the XR-1's problems seemed to be approaching resolution by late 1944, the protracted development of the aircraft meant that alternative, improved helicopters, such as Sikorsky's XR-4
Sikorsky R-4
The Sikorsky R-4 was a two-place helicopter designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter to enter service with the United States Army Air Forces, Navy, and...
, less expensive and more maneuverable than Platt-LePage's aircraft, were becoming available. In addition, even the XR-1A's improvements had failed to cure the aircraft of all of its control and vibration problems, and the AAF's Air Material Command considered the company "inept" in its work, applying a "hit-or-miss method" to research and development. As a result of this assessment, the Army's contracts with the company were universally cancelled in early April 1945.
Following the cancellation of the Army's contract, the XR-1 was returned to the company, Platt-LePage believing that the design had potential as a civilian aircraft. The planned civilian version, the PL-9, would have been an enlarged, twin-engined aircraft; however Platt-LePage was by now in serious financial difficulty following the cancellation of its Army contract, and in mid 1946 the XR-1's flight test program was concluded, the aircraft being retired to the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
.
In the meantime, the company's former test pilot, Lou Leavitt, had purchased the wreckage of the XR-1A at a price of 4 cents per pound. Leavitt had formed a new company, Helicopter Air Transport, intending to provide helicopter flight training in anticipation of a postwar aviation boom, and he returned the XR-1A to flying condition. The projected boom failed to materialise, however, and HAT quickly entered bankruptcy
Bankruptcy
Bankruptcy is a legal status of an insolvent person or an organisation, that is, one that cannot repay the debts owed to creditors. In most jurisdictions bankruptcy is imposed by a court order, often initiated by the debtor....
, Leavitt selling the XR-1A to Frank Piasecki
Frank Piasecki
Frank Piasecki was an American engineer and helicopter aviation pioneer. Piasecki pioneered tandem rotor helicopter designs and created the compound helicopter concept of vectored thrust using a ducted propeller.-Biography:...
, another former Platt-LePage employee who had now started his own helicopter company. Piasecki soon grounded the aircraft due to airworthiness concerns, and used the airframe in the development of the PA-2B, a planned tiltrotor
Tiltrotor
A tiltrotor is an aircraft which uses a pair or more of powered rotors mounted on rotating shafts or nacelles at the end of a fixed wing for lift and propulsion, and combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft...
which failed to proceed beyond the mock-up stage.
Survivors
Following the conclusion of flight testing, the XR-1 was returned to the Army Air Forces, who placed the aircraft in storage before donating it to the Smithsonian InstitutionSmithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
's National Air and Space Museum
National Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...
. The unrestored aircraft is stored at the Paul Garber Restoration and Storage Facility in "remarkable condition".
Variants
XR-1- First prototype; one built.
XR-1A
- Second prototype with increased cockpit glazing and improved engine; one built.
YR-1A
- Seven pre-production aircraft ordered; contract cancelled before any completed.
PL-4
- Proposed armedGunshipThe term "gunship" is used in several contexts, all sharing the general idea of a light craft armed with heavy guns.-In Navy:In the Navy, the term originally appeared in the mid-19th century as a less-common synonym for gunboat.-In military aviation:...
variant of the XR-1, fitted with four machine gunMachine gunA machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
s in a reprofiled nose.
Piasecki PA-2B
- Proposed tiltrotorTiltrotorA tiltrotor is an aircraft which uses a pair or more of powered rotors mounted on rotating shafts or nacelles at the end of a fixed wing for lift and propulsion, and combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft...
based on XR-1 airframe; not built.
Specifications (XR-1A)
See also
External links
- "Twin Rotors", October 1944, Popular Science bottom of page 78