Convair R3Y Tradewind

The Convair R3Y Tradewind was an American 1950s turboprop-powered flying boat designed and built by Convair.

R3Y Tradewind
R3Y Tradewind
An R3Y-1 Tradewind low over San Francisco Bay near NAS Alameda
Role transport flying boat
Manufacturer Convair
First flight 22 February 1954 (R3Y-1)
Introduction 1956 (R3Y-1)
Retired 1958
Primary user United States Navy
Number built 11 (R3Y) & 2 (P5Y)

Design and development

Convair XP5Y-1 Tradewind at San Diego 1950
The Convair XP5Y-1 prototype in 1950. It first flew on 18 April 1950 at San Diego and crashed in 1953.

Convair received a request from the United States Navy in 1945 for the design of a large flying boat using new technology developed during World War II, especially the laminar flow wing and still-developing turboprop technology. Their response was the Model 117. It was a large high-wing flying boat with Allison T40 engines driving six-bladed contra-rotating propellers. It had a sleek body with a single-step hull and a slender high-lift wing with fixed floats. The Navy ordered two prototypes on 27 May 1946. Designated XP5Y-1, the first aircraft first flew on 18 April 1950 at San Diego. In August the aircraft set a turboprop endurance record of eight hours six minutes. The Navy decided not to proceed with the patrol boat version, instead directing that the design should be developed into a passenger and cargo aircraft.

One of the XP5Y-1 prototypes was lost in a non-fatal accident on 15 July 1953, while design and development continued on the passenger and cargo version of the aircraft. The transport and cargo version was designated the R3Y-1 Tradewind and first flew on 25 February 1954. Major changes were the removal of all armament and of the tailplane dihederal, the addition of a 10 ft (3.05 m) port-side access hatch, and redesigned engine nacelles to accept improved T40-A-10 engines. Cabin soundproofing and airconditioning were added for pressurised accommodation for 103 passengers or 24 tons of cargo. As a medevac aircraft, 92 stretcher cases could be carried.

R3Y-2 bow door w tractor NAN10-54
R3Y-2 variant loading a tractor

A total of eleven aircraft were built. The first two prototypes built were in P5Y configuration, armed with 8,000 lb (3,600 kg) of munitions (bombs, mines, depth charges, torpedoes) and five pairs of 20 mm cannon in fore and aft side emplacements and a tail turret. The next five were built as R3Y-1 aircraft, intended for troop transport and inflight refuelling tanker service. The final six were built as the R3Y-2 variant with a lifting nose and high cockpit (similar in concept to the C-5 Galaxy's nose and cockpit) for heavier transport and landing-ship duties.

The front-loading R3Y-2 aircraft with a hinged nose and high cockpit were intended to be a Flying LST (landing craft). In practice, it was discovered that it was almost impossible for the pilots to hold the aircraft steady and nose on to the beach while the aircraft was loaded or unloaded.[1] The aircraft were converted into tankers for the inflight refuelling role. They had a short service life because of the unsolvable unreliability problems of their Allison T40 turboprop engines, a fate common to most T40-powered aircraft, such as the Douglas A2D Skyshark attack aircraft.

Operational service

R3Y Tradewind refuelling
R3Y-2 Tradewind refuels a record four fighters in flight, 1956

The R3Y set a transcontinental seaplane record of 403 mph in 1954 by utilizing the speed of high-altitude jetstream winds. This record still stands.

After service trials the aircraft were delivered to US Navy transport squadron VR-2 on 31 March 1956. Problems with the engine/propeller combination led to the ending of Tradewind operations and the unit was disbanded on 16 April 1958.

The six R3Y-2s were converted into four-point in-flight tankers using the probe-and-drogue method. In September 1956 one example was the first aircraft to successfully refuel four others simultaneously in flight in 1956, refuelling four Grumman F9F Cougars.

The program was halted after thirteen aircraft were built, the reason being the unreliability of the Allison T-40 turboprops. The crash of one of the two XP5Y-1 aircraft was judged due to catastrophic engine failure; when little progress was being made with the engine problems, the Navy halted the program. Subsequently, three more aircraft were lost through engine failures, and the Navy gave up on the T-40 and aircraft powered by it. All the P5Y and R3Y aircraft were grounded in 1958 and subsequently broken up.

Variants

XP5Y-1
Prototype patrol flying boat, two built.
R3Y-1
Transport aircraft for the United States Navy with side loading door, 5 built.
R3Y-2
Assault transport aircraft for the USN with shorter nose incorporating an upward-opening loading door, later converted to four-point tankers for probe-and-drogue operations, six built.

Operators

 USA

Specifications (R3Y-1)

Convair R3Y Tradewind drawings
Line drawings for the R3Y-1/-2.

Data from Naval Fighters #34 : Convair XP5Y-1 & R3Y-1/-2 Tradewind[2]

General characteristics

  • Crew: 7 flight crew + cabin crew / loadmasters
  • Capacity: 80 pax / 72 litter patients with 8 medical staff
R3Y-2: 103 pax / 92 litter patients with 12 medical staff
  • Length: 139 ft 8.3 in (42.578 m)
R3Y-2: 141 ft 1.7 in (43 m)
  • Wingspan: 145 ft 9.7 in (44.442 m)
  • Width: 12 ft 6 in (3.81 m) maximum hull beam
  • Height: 49 ft 0 in (14.94 m) keel to fin tip
51 ft 5.2 in (16 m) on beaching gear
  • Wing area: 2,100.7 sq ft (195.16 m2)
  • Aspect ratio: 10
  • Airfoil: root: NACA 1420 ; Mid span NACA 4417 ; tip: NACA 4412 ; average thickness 18%
  • Gross weight: 145,500 lb (65,998 kg)
  • Max takeoff weight: 165,000 lb (74,843 kg)
  • Landing weight: 136,739 lb (62,024 kg) with maximum cargo
  • Fuel capacity: 66,000 lb (29,937 kg)
  • Powerplant: 4 × Allison T40-A-10 turboprop engines, 5,332 shp (3,976 kW) each
  • Propellers: 6-bladed Aeroproducts, 15 ft (4.6 m) diameter contra-rotating fully-feathering reversible propellers

Performance

  • Maximum speed: 299 kn (344 mph, 554 km/h) at 21,000 ft (6,401 m) at MTOW
308 kn (354 mph; 570 km/h) at 23,000 ft (7,010 m) at normal gross weight
  • Cruise speed: 300 kn (350 mph, 560 km/h) average at 29,000–34,200 ft (8,839–10,424 m)
  • Stall speed: 98 kn (113 mph, 181 km/h) at MTOW power off
89.4 kn (102.9 mph; 165.6 km/h) at 136,739 lb (62,024 kg) power off
87.5 kn (100.7 mph; 162.1 km/h) at 136,739 lb (62,024 kg) with approach power
  • Range: 2,420 nmi (2,780 mi, 4,480 km)
  • Combat range: 1,240 nmi (1,430 mi, 2,300 km)
  • Service ceiling: 30,300 ft (9,200 m) at MTOW
  • Rate of climb: 1,910 ft/min (9.7 m/s) at MTOW
  • Time to altitude: 20,000 ft (6,096 m) in 12 minutes 18 seconds at MTOW
30,000 ft (9,144 m) in 43 minutes 12 seconds
  • Wing loading: 78.5 lb/sq ft (383 kg/m2) at MTOW
  • Power/mass: 0.1293 hp/lb (0.2126 kW/kg) at MTOW
  • Take-off time: 50 seconds in calm sea conditions at MTOW

See also

Related lists

References

Notes

  1. ^ Ginter 1996, p. 94.
  2. ^ Ginter, Steve (1996). Naval Fighters #34 : Convair XP5Y-1 & R3Y-1/-2 Tradewind (1st ed.). Simi Valley CA: S. Ginter. ISBN 0942612345.

Bibliography

External links

Allison T40

The Allison T40, company designation Allison Model 500, was an early American turboprop engine composed of two Allison T38 power sections driving a contra-rotating propeller via a common gearbox.

Contra-rotating propellers

Aircraft equipped with contra-rotating propellers, also referred to as CRP, coaxial contra-rotating propellers, or high-speed propellers, apply the maximum power of usually a single piston or turboprop engine to drive two coaxial propellers in contra-rotation (rotation about the same axis in opposite directions). Two propellers are arranged one behind the other, and power is transferred from the engine via a planetary gear or spur gear transmission. Contra-rotating propellers are also known as counter-rotating propellers, although counter-rotating propellers is much more widely used when referring to airscrews on separate shafts turning in opposite directions.

Convair

Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953 it was purchased by General Dynamics, and operated as their Convair Division for most of its corporate history.

Convair is best known for its military aircraft; it produced aircraft such as the Convair B-36 Peacemaker, the F-102 Delta Dagger, the F-106 Delta Dart, and the B-58 Hustler bombers. It also manufactured the first Atlas rockets, including the rockets that were used for the manned orbital flights of Project Mercury. The company's subsequent Atlas-Centaur design continued this success and derivatives of the design remain in use as of 2019.

The company also entered the jet airliner business with its Convair 880 and Convair 990 designs. These were smaller than contemporary aircraft like the Boeing 707 and Douglas DC-8, but somewhat faster than either. This combination of features failed to find a profitable niche and the company exited the airliner design business. However, the manufacturing capability built up for these projects proved very profitable and the company became a major subcontractor for airliner fuselages.

In 1994 most of the company's divisions were sold by General Dynamics to McDonnell Douglas and Lockheed, with the remaining components deactivated in 1996.

List of aircraft (Co–Cz)

This is a list of aircraft in alphabetical order beginning with 'Co' through to 'Cz'.

List of seaplanes and amphibious aircraft

The following is a list of seaplanes and amphibious aircraft, which includes floatplanes and flying boats, by country of origin.

Seaplanes are any aircraft that has the capability of landing on water while amphibious aircraft are equipped with wheels to alight on land, as well as being able to land on the water. Flying boats rely on the fuselage or hull for buoyancy, while floatplanes rely on external pontoons or floats. Some experimental aircraft used specially designed skis to skim across the water but did not always have a corresponding ability to float.

This list does not include ekranoplans, 'Wing-In-Ground-effect' (WIG), water-skimmers, wingships or similar vehicles reliant on ground effect.

Tradewind

A trade wind is a wind pattern.

Trade Wind or Tradewind can also refer to:

Trade Winds (film), 1938 film directed by Tay Garnett

Trade Wind, alternate name for the 1998 film At Sachem Farm

Trade Wind, a book by M. M. Kaye

Tradewind, one of the characters from The Incredibles

Convair R3Y Tradewind, an American 1950s heavy transport flying-boat

"Trade Winds", a poem by John Masefield set to music in 1919 by Frederick Keel

"Trade Winds", a song written in 1940 by Charles Tobias and Cliff Friend

"Trade Winds", a song by Natasha Barrett

"Tradewinds", a song from John Denver's 1977 album, I Want To Live

Tradewinds, the original name of Styx

The Trade Winds, a 1960s pop group

Tradewinds (game), a PC game series

Tradewind (schooner), a 1911 Dutch tall ship

Tradewinds Airlines, a cargo carrier

TradeWinds (newspaper), a business newspaper covering ocean shipping

Tradewind Pictures, a German production company

Tradewinds Charters, a regional air-charter company founded in 1976 as a subsidiary of Singapore Airlines

Tradewinds Tours And Travel, a travel agency which is part of Singapore Airlines Group

Tradewinds the Airline, the name of a subsidiary of Singapore Airlines

Turboprop

A turboprop engine is a turbine engine that drives an aircraft propeller.In its simplest form a turboprop consists of an intake, compressor, combustor, turbine, and a propelling nozzle. Air is drawn into the intake and compressed by the compressor. Fuel is then added to the compressed air in the combustor, where the fuel-air mixture then combusts. The hot combustion gases expand through the turbine. Some of the power generated by the turbine is used to drive the compressor. The rest is transmitted through the reduction gearing to the propeller. Further expansion of the gases occurs in the propelling nozzle, where the gases exhaust to atmospheric pressure. The propelling nozzle provides a relatively small proportion of the thrust generated by a turboprop.In contrast to a turbojet, the engine's exhaust gases do not generally contain enough energy to create significant thrust, since almost all of the engine's power is used to drive the propeller.

Manufacturer
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Fighters and
attack aircraft
Civilian transports
Military transports
Experimental aircraft
General Dynamics
USN/USMC transport designations 1931–1962
Atlantic Aircraft
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Curtiss
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Bellanca
Kinner
Kreider-Reisner
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Convair
USN/USMC patrol aircraft designations 1923–1962
Patrol
Patrol Bomber
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