The Tay was developed in the first instance by Rolls-Royce from the basic Nene design. Two units of the type were test-flown in a special Vickers Viscount. It has been further improved by the Pratt and Whitney and HispanoSuiza concerns, which, respectively, hold the American and French licences.
By 1948, Rolls-Royce had designed the Tay turbojet, also a centrifugal-flow design. However, as Rolls-Royce was then developing an improved design with an axial compressor, which would become the Avon, the development and production of the Tay turbojet was left to Pratt & Whitney. However, Rolls-Royce retained the rights to the Tay outside of the United States.
A total of 4,108 were built.
The Tay/J48 was a thirty percent enlargement of the preceding Nene/J42, and was produced both with and without afterburning.
Hispano-Suiza Tays have been installed in Dassault Mystere II, III and IV fighters, and the Tay 250 is for the Mystere IVA. A development of the Tay by the French company is called the Verdon (following the “River” nomenclature) and has a modified compressor with new guide-vanes, revised flame-tubes and combustion chambers, and new turbine-blades and disc. A special afterburner has been developed for this engine, which is to replace the Tay in the Mystere IVA.
The new J48 in 1950 powering the North American YF-93A developed 6250 lb thrust, with another 1750 lb with afterburner. It was also planned to power the Navy’s new F9F-5 Panther.
Variants:
RB.44 Tay
Rolls-Royce development engines only, no production.
Hispano-Suiza Verdon
The Tay built and developed under licence in France.
Pratt & Whitney J48
The Tay built and developed under licience in the United States.
J48-P-1: 6,000 lbf (26.7 kN), 8,000 lbf (35.6 kN) thrust with afterburning
J48-P-2: 6,250 lbf (27.8 kN), 7,000 lbf (31.1 kN) thrust with water injection
J48-P-3: 6,000 lbf (26.7 kN), 8,000 lbf (35.6 kN) thrust with afterburning
J48-P-5: 6,350 lbf (28.2 kN), 8,750 lbf (38.9 kN) thrust with afterburning
J48-P-6: 6,250 lbf (27.8 kN), 7,000 lbf (31.1 kN) thrust with water injection
J48-P-7: 6,350 lbf (28.2 kN), 8,750 lbf (38.9 kN) thrust with afterburning
J48-P-8: 7,250 lbf (32.2 kN) thrust
J48-P-8A: 7,250 lbf (32.2 kN) thrust
Applications:
Tay
Vickers 663 Tay Viscount
Verdon
Dassault Mystère IV
J48
Grumman F9F-5 Panther
Grumman F9F-6/F9F-8 Cougar
Lockheed F-94C Starfire
North American YF-93
Specifications:
Hispano-Suiza Verdon 350
Type: Turbojet
Length: 103.2 in (2,621 mm)
Diameter: 50 in (1,270 mm)
Dry weight: 2,061 lb (935 kg)
Compressor: Double sided centrifugal compressor
Combustors: Nine tubular combustion chambers
Turbine: Single-stage turbine
Fuel type: AVTUR / JET-A1 / F-34 etc.
Oil system: Pressure spray lubricated with scavenging
Maximum thrust: 7,710 lbf (34 kN) at 11,000 rpm
Overall pressure ratio: 4.9
Specific fuel consumption: 1.1 lb/lb/hr
Thrust-to-weight ratio: 3.74
Pratt & Whitney J48-P-8A
Type: Turbojet
Length: 202 in (513 cm)
Diameter: 50 in (127 cm)
Dry weight: 2,101 lb (953 kg)
Compressor: Centrifugal compressor
Maximum thrust: 7,250 lbf (32.2 kN) thrust
All Aero 