De Havilland Spectre
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2008-05-28T21:47:50Z
GraemeLeggett
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tidy up wl
{{infobox rocket engine
|name=Spectre
|country_of_origin=Britain
|manufacturer=[[de Havilland]]
|type=liquid
|oxidiser=hydrogen peroxide
|fuel=kerosene
|thrust=8,000 [[lbf]] (35.7 kN) (full power)
}}
[[Image:De Havilland Spectre rocket engine.jpg|thumb|Spectre rocket engine]]
The '''de Havilland Spectre''' was a [[rocket engine]] built by [[de Havilland]] in the 1950s. It was one element of the intended mixed powerplant for combination rocket-jet interceptor aircraft for the [[Royal Air Force]], such as the [[Saunders-Roe SR.53]].
The Spectre was a bipropellant engine burning [[kerosene]] and [[hydrogen peroxide]]. The power could be controlled from 10-100% delivering 8,000 [[lbf]] (35.7 kN) of thrust at full power. In the [[SR.53]] it used the same fuel tanks as the turbojet engine and if run at full power was expected to consume the full load in about seven minutes.
In 1952 static testing commenced with the Spectre DSpe.l. The aircraft industry had no precedent for an engine which would gain in thrust with altitude and the required maximum thrust was estimated at between 2,000 lbf and 15,000 lbf thrust. The design was based on a variable thrust which could be throttled from 8,000 lbf to 2,000 lbf. Design philosophy was matched to the mixed power concept of an aircraft having both a turbojet and rocket engine for maximum operational flexibility. <ref>{{cite journal
|title=More About the Super Sprite
|journal=The Aeroplane
|date=29 July 1955
}}</ref>
Technological innovation embraced the [[Barske centrifugal pump|Barske]] high-speed open-impeller [[centrifugal pump]]s,<ref>{{cite journal
|last=Barske
|first=U. M.
|title=Development of Some Unconventional Centrifugal Pumps
|journal=Proc. IMech Engrs,
|volume=Vol. 174
|issue=No. 11
|date=1960
}}</ref> as formerly researched in the [[Hellmuth Walter|Walter]] organisation, [[regenerative cooling]] with pump stages both upstream and downstream, gauze catalyst packs, low-loss internal-flow turbine and the use of straight kerosene fuel. The aircraft tanks were to be pressurised to suppress pump [[cavitation]] problems. <ref>{{cite journal
|author=W. N. Neat,
|title=Development of the Spectre (Lecture to Royal Aeronautical Society)
|date=14 November 1958
|journal=Flight
|url=http://www.cue-dih.co.uk/aerospace/aeropdfs/htp_for_prop.pdf
}}</ref>
It went through rig tests commencing in 1953, bench tests from mid-1954, and testing in two [[English Electric Canberra|Canberra]]s. From flight approval in Autumn 1956, flight experience again posed altitude starvation problems. Clearance was given for flight in the SR.53 prototype from May [[1957]]. <ref>{{cite journal
|title=Enterprise in Rocketry Activity at De Havilland Engine Co.
|journal=The Aeroplane
|date=4th March 1955
|url=http://www.cue-dih.co.uk/aerospace/aeropdfs/htp_for_prop.pdf
}}</ref> <ref>{{cite web
|url=http://www.skomer.u-net.com/projects/spectre.htm
|title=Spectre
|publisher=Skomer
}}</ref>
In October 1957 a contract was announced for a more advanced version of the aircraft as the [[SR.177]] to utilise a revised design Spectre DSpe.5 engine together with a reheated supersonic capability 14,000 lb. thrust [[de Havilland Gyron Junior|Gyron Junior]] [[turbojet]] engine, thus meeting a full mixed power aircraft concept. In conjunction with the new engine, development had been undertaken with two major ancillaries, a peroxide starter for the gas turbine and a peroxide [[auxiliary power unit]]. Virtually on the heels of the announcement of the contract came the notorious [[1957 Defence White Paper]] declaring that all future combat would be undertaken by computer controlled missiles, and that manned interceptors were now considered obsolete.
Development flying of the SR.53 continued through 39 flights operating to Mach 1.33, and to altitudes at 55,000 ft, as research and construction proceeded on the SR.177, until its cancellation in 1958.
After merging of interests in 1959, it was manufactured by [[Bristol Siddeley]].
Variants included:
: Dspe.1 initial version
: Dspe.2 constant thrust version, simpler design
: Dspe.3 development of Dspe.1 with variable thrust
: Dspe.4 development of Dspe.2
: Dspe.5 further development of Dspe.1
== Double Spectre ==
A doubled version of this engine was used for early flight-testing of [[Blue Steel]] nuclear stand off bomb, with two chambers arranged vertically. <ref>{{cite web
|url=http://www.skomer.u-net.com/projects/sr53.htm
|title=Double Spectre
|publisher=Skomer
|format=image
}}</ref>
The conventional Spectre DSpe.5 had been developed alongside a DSpe.4 [[RATO]] variant, the latter for the [[Avro Vulcan]] and [[Handley-Page Victor]] [[V bomber]]s, another programme subsequently cancelled after a single trial take-off of a Victor from the de Havilland aerodrome at [[Hatfield]]. These two engines were then used in combination to power the development rounds of the [[Blue Steel missile]] stand-off bomb, together with the peroxide [[auxiliary power unit|APU]], from its first flight in October 1959.
== References ==
{{reflist}}
{{DHaeroengines}}
[[Category:Aircraft rocket engines]]
{{engine-aircraft-stub}}
{{rocket-stub}}
[[it:De Havilland Spectre]]