FLIGHTLINE: 126 - CONVAIR R3Y TRADEWIND
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- A Convair R3Y Tradewind transport sits on a cradle prior to being moved into San Diego Bay, 4 November 1954. | Photo: US Navy
FLIGHTLINE: 126 - CONVAIR R3Y TRADEWIND
The Tradewind was first ordered as a post-WWII patrol bomber, but was then changed to a transport before being canceled entirely.
After the end of WWII, the US Navy requested a new long range patrol bomber that would take advantage of the technologies developed during the war, including laminar flow wings and turboprop engines. Convair responded with the Model 117, a flying boat with a high wing, powered by Allison engines driving six-bladed contra-rotating props. Two prototypes of the plane, designated XP5Y-1 were ordered on 27 May 1946, with the first flight occurring on 18 April 1950.
-Orthograph of the P5Y-1 Tradewind. | Illustration: US Navy
-The Convair XP5Y-1 Tradewind on the day of its first flight on 18 April 1950. | Photo: US Navy
The P5Y were designed to carry 8,000lbs of weapons, and were armed with five pairs of 20mm cannon for self-defense. The T40 engine, which was essentially two T38 engines driving contra-rotating props via a common shaft, provided copious power, granting the plane with a maximum speed of 350mph and a climb rate of nearly 2,000 feet-per-minute, roughly that of a P-61 Black Widow. The design of the T40 also allowed for one of the power sections to be shut down for cruising, giving the plane a a range of 2,500 miles. In August of 1950, one of the YP5 prototypes set an endurance mark for turboprop aircraft of eight hours six minutes. A non-fatal accident destroyed one of the prototypes on 15 July 1953.
-Orthographs of the R3Y-1 and -2 models. | Illustration: US Navy
The rapid progress of technology post-war saw the Navy's interest in the Tradewind change, and Convair was ordered to modify the design into a transport. The changes included removing the defensive cannons, deleting the dihedral from the horizontal stabilizers, changes to the engine nacelles to fit upgraded T40-A-10 engines, the addition of soundproofing, air conditioning, and pressurization equipment for the cargo compartment, and a 10 foot hatch on the port side to load and unload cargo. The R3Y-1 could accommodate 103 passengers or twenty-four tons of cargo. First flight of the -1 variant was on 25 February 1954, with 5 total examples completed. Also in 1954, R3Y-1 "Coral Sea", using a strong jet stream, set a transcontinental speed record for seaplanes at 403mph.
-The 4 November 1954 public unveiling of the R3Y-1 Tradewind at Convair's plant in San Diego. | Photo: San Diego Air & Space Museum
-An RY3-1 on specialized beaching gear. | Photo: US Navy
The last six Tradewinds were R3Y-2 models, with the nose and crew compartment changed to include a swing-up nose which allowed for drive-on/drive-off cargo like jeeps and light armored vehicles. The Navy intended for these aircraft to be flying LSTs, with the aircraft directly unloading onto beachheads. In practice however, the aircraft, loaded or unloaded, were unable to hold steady and beach, and eventually all the Tradewinds were modified to act as aerial refueling tankers.
-A tractor being loaded onto an R3Y-2. | Photo: US Navy
-A R3Y-2 Tradewind set a record by simultaneously refueling four Grumman F9F-8 Cougar fighters in September 1956. | Photo: US Navy
The Tradewind had a short service life, with US Navy Transport Squadron 2 (VR-2) standing up with the plane on 31 March 1956, and the unit being disbanded and the type being grounded on 16 April 1958. Reliability problems with the T40 engine (which doomed the other aircraft that used the type, such as the Convair XFY and Lockheed XFV VTOL fighters, the Douglas A2D Skyshark and the Republic XF-84H Thunderscreech) as well as several incidents related to the props disintegrating mid-flight, as well as improvements in jet engines, ICBMs and changing strategies saw the end of seaplanes and flying boats.
-Four Tradewinds, two R3Y-1s and two -2s, flying over Alcatraz in 1957. | Photo: US Navy