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Halford H1
de Havilland Goblin
Allis-Chalmers J36

de Havilland Goblin

An offshoot of the Whittle design was the Frank Halford designed Halford H1. It was more powerful at around 2,300 lbs thrust but also larger and heavier. Design of the engine was carried out by Frank Halford at his London consulting firm starting in April 1941. It was based on the basic design pioneered by Frank Whittle, using a centrifugal compressor providing compressed air to sixteen individual flame cans with a straight through flow from the inlet at the front to the jet pipe, from which the exhaust powered a single-stage axial turbine. Compared to Whittle designs, the H-1 was "cleaned up" in that it used a single-sided compressor with the inlet at the front, and a "straight through" layout with the flame cans exhausting straight onto the turbine. Whittle's designs used a "reverse flow" layout that piped the hot air back to the middle of the engine, in order to "fold" it and reduce its length. Halford's changes made his engine somewhat simpler than Whittle's designs, notably allowing one of the main bearings to be removed. Nevertheless it was a fairly compact design, even without the Whittle-style "folding".



The H-1 first ran on 13 April 1942, and quickly matured to produce its full design thrust within two months. It first flew on 5 March 1943 in the Gloster Meteor DG206, and on 26 September in the de Havilland Vampire. The Goblin was the second British jet engine to fly, and the first to pass type tests and receive a "Gas Turbine" class type rating. It was around this time that de Havilland purchased Halford's company and set him up as the chairman of the de Havilland Engine Company, with the engine name changing from H-1 to "Goblin", while the new H-2 design became the "Ghost" - de Havilland jet and rocket engines were all named after spectral apparitions.

In July 1943, one of the two H-1s then available (actually the spare engine intended as a backup for the one installed in the Vampire prototype) was sent to the United States, where it was selected to become the primary engine of the Lockheed P-80 Shooting Star. This engine was fitted to the prototype which first flew on 9 January 1944. The engine was later accidentally destroyed in ground testing, and was replaced by the only remaining H-1 from the prototype Vampire. Allis-Chalmers was selected to produce the engine in the US as the J36, but ran into lengthy delays. Instead, the Allison J33, developed by a General Electric as the I-40 (their greatly improved 4,000 lbf (18 kN) version of the J31, itself based on Whittle's W.1), was selected for the production P-80A.


“One example of the Allis-Chalmers licensed de Havilland Halford H-1 jet engine prototype was near Wichita Kansas in 2012. Ernst Nutsch had an Allis-Chalmers private museum in Washington Kansas. He had bought the jet engine at an auction in Iowa circa 1998. The condition was fair to good and it was on a repair stand. The Serial plate had Allis-Chalmers name on it as license from de Havilland, model of H-1, plus if I remember correctly it had a US Navy contract number.
The museum was sold off and Ernst passed away in 2010 however at the time the engine was not sold. The family still had it five years ago (in 2012).”
Alan Jones



H.1/Goblin I
Developed about 2,300 lbf (10.2 kN) thrust (nominal thrust for prototype) and 2,700 lbf (12.0 kN) for production models.

Goblin II
3,100 lbf (13.8 kN)

Goblin 3
3,350 lbf (14.9 kN)

Goblin 35
3,500 lbf (15.6 kN)

Goblin 4
3,750 lbf (16.7 kN)

Allis-Chalmers J36
Licence production in the United States by Allis-Chalmers.

Aircraft applications:

de Havilland Vampire
de Havilland Swallow
Curtiss XF15C-1
Fiat G.80
Gloster Meteor
Lockheed XP-80
Saab 21R

Alternative applications:

Bluebird K4


D.H Goblin II D.Gn 27
Type: Turbojet
Length: 107 in (2,718 mm)
Diameter: 50 in (1,270 mm)
Dry weight: 1,550 lb (703 kg)
Compressor: Single sided, centrifugal flow
Combustors: 16 chambers
Turbine: Single stage axial flow
Fuel type: Kerosene (R.D.E. / F / KER)
Oil system: metered pressure spray at 50 psi (344.7 kPa) dry sump, 40 S.U. secs (13 cs) (Intavia 620) grade oil
Maximum thrust: 3,000 lbf (13.34 kN) at 10,200 rpm at sea level
Overall pressure ratio: 3.3:1
Turbine inlet temperature: 1,472 °F (800 °C)
Fuel consumption: 3,720 lb/hr (465, (1,687 kg/hr) or (2,114 l/hr)
Specific fuel consumption: 1.18 lb/lbf/hr (120.285 kg/kW/hr)
Thrust-to-weight ratio: 1.9 lbf/lb (0.0186 kN/kg)


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