British Westcott « Delta » rocket engines


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Mysterious Rocket Engine
FLIGHT, 14 September 1956
Most of the Ministry stand at Farnborough was devoted to
non-warlike equipment, but nobody could fail to be impressed by
the chamber for a liquid-oxygen and kerosine motor placarded as
"over 50,000 lb thrust." Although this is only of the same order
as the V-2 chamber of a dozen years ago the techniques are incomparably
more advanced. The chamber jacket had 32 identical
consituent parts each forming a tubular axial passage for regenerative
kerosine cooling. Each segment was formed from side-byside
strips machine-welded and hydro-pressed. Combustion
pressure was stated to be approximately 500 lb.

A Westcott engine Delta 2 or Delta 3 chamber the only British engines with sufficient thrust?
Woo the box was looking me in the face when I ventured into my attic...

The Aeroplane page 414 - 14th September 1956 Second S.B.A.C. Show Report.

As usual, the Ministry of Supply brought off its annual coup. Not only did it show the Geophysical Year rocket on its indoor and outdoor stand, but it revealed the existence of a 50,000 lb. rocket nozzle. This is a remarkably ingenious device composed of fluted sections of welded 18/8 stainless steel.

Flat “blades” of stainless steel – rather like leaves from a flag iris – are welded together, one on top of the other and seam welded down most of the centreline. The unit is then hydraulically inflated in a mould to form a hollow sealed pipe, double over most of its length. The units are welded to form a venturi with a bulbous combustion chamber.

In its final form the longitudinal ducts in the blades are connected at the venturi lip and also by a gallery round the combustion chamber in such a way that kerosene enters one “blade”, travels down it to the lip and then returns up the next blade to enter the combustion chamber through microscopic holes. LOX is brought in at the base of the chamber and injected through holes in the roots of the “blades” which duct the kerosene to the nozzle lip – these having an internal barrier to give them their dual purpose. Thus, the combustion chamber is fed by alternate and adjacent kerosene and LOX sprays.

The combustion pressure is 500 p.s.i. and the propellant has therefore to be injected at 800 p.s.i. The nozzle is, of course, well cooled and the metal thickness is only about 20 s.w.g. It is remarkable that this thin “quilted” structure can withstand not only the high combustion temperatures – probably 3,000° C. – but the high internal skin pressures also.

I must admit to not being well versed in rocketry, but what does the above mean in terms of rocket development, how advanced technologically is such a combustion chamber?

Do we know of any projects with which this motor was associated?
sealordlawrence said:
I must admit to not being well versed in rocketry, but what does the above mean in terms of rocket development, how advanced technologically is such a combustion chamber?

Do we know of any projects with which this motor was associated?

Barrington Bond Fantastic,

This is a big clue “a venturi with a bulbous combustion chamber.”

This is a excellent description of the Westcott Delta 2 design which was one of the two rocket engine designs given to Bristol to develop to production standard for the English Electric LRBM, or maybe specifically in this case as a back up to the Future RZ2 development in case it failed?

The Westcott/Bristol Delta 2 had a thrust rating of 137,500 lbf., however it was dropped with in weeks of the contract being given and work concentrated on the big Delta 3, rating 187,500lbf because it had more potential and the combustion chamber was more advanced “bean can” combustion chamber with better characteristics.

I do not know the full answer but may be triplication of effort was wasteful of limited resources and because the Delta 3 would have guaranteed a complementary performance for the longer ranged Commonwealth deployed missile.
Maybe cost cutting as well?


The Bulbous is V-2 type, the "bean can" is more advanced

It is important because it gives evidence for a different perspective to the “Blue Streak Story” and shows that other work was being done which is not generally acknowledged now days

These were serious engines being developed with intent of such a size as to be able to fulfil power source requirement for both Missile round and Satellite Launch Vehicle.

There a bit too big to hang on the back of an aircraft.

There was the Westcott Delta 1 but can not remember rating, but Delta series were Kerosine LOX engines, maybe this was 50,000lbf engine but the Flight article did say a liquid-oxygen and kerosine motor placarded as
"over 50,000 lb thrust”?

Just a thought, Napier would have known about the engine requirement, did they propose a big engine of there own and what fuel combination would they have used?
Barrington Bond said:
Aeronautics page 41 Oct 1956...

Hi Barry,

TOPMAN, will forward this gem to other interested parties. It got as far as tin bashing, what is interesting is that no pump assemblies related to the projects either the Delta Two or the Delta Three were shown publically.
Although a former Director of RPE Westcott remembers seeing when he was still junior a very large pumps assembly, larger than the RZ2, but was not privy to its purpose.
I met a chap who fabricated the Delta 3 thrust chamber several years ago, some of the antics they got up too were amazing.
What is not known publically is that the Ansty Establishment had cracked the problem of building very large light weight high thrust HTP rocket engines, but can not give details of how. Only an indication of what was possible in the UK at the time.
I've been sitting on this pic for a few months as it is only described as an experimental rocket engine in the De Havilland Gazette I got it from. Looks to be the same though...



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The Aeroplane 26 July 1957 Exhibition at Cranfield.
And 2 August 1957.


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Barrington Bond said:
The Aeroplane 26 July 1957 Exhibition at Cranfield.
And 2 August 1957.

Thanks for the new pictures , I passed your other pictures on to a former member of one of the rival engine teams.
It has caused some excitement because there might be a surviving chamber that was unidentified and that might be one and the same 50,000lbf chamber.
Will let you all know the outcome as and when.
Browsing through some old Interavias today and came across a picture of this engine and it said it was a Westcott one.

It's either a Delta 1 or Delta 2 - thrusts 50,000lb and 135,000lb. They were the only British indigenous LOX/kerosene chambers, and work on them became rather redundant after RR licenceed the NAA chamber which became the RZ 2.
It was only a small caption - I don't think it said anything new but was the first I'd seen stating it was a Westcott one.

Couple of years ago I read a short history of Westcott by someone who worked there. I'm sure it mentioned that the tubular construction idea was brought back by someones visit to the USA. Unlicensed copying :eek:

Tubular construction was also used on RZ 2, and that had been licenced from the US as early as 1955. Ironically, that style of contruction has now been abandoned.
Well given the date, the construction and the listed thrust on the the placard the evidence seems pretty conclusive that it was from the Bristol Delta 1, unless there were any other 50,000lb thrust spherical rocket motors floating around in the UK in 1957?

Also, from a memorandum to the Cabinet Defence Committee dated 5th January 1955 (Found in CAB 131/15):

We are also working on upon an anti-ship guided bomb (Green Cheese) and upon a medium range ballistic rocket for the delivery of a thermo-nuclear warhead at ranges up to 1,500 miles. Both these projects are at a very early stage.
Last edited:
JFCF: that was (to be) Blue Streak based on US data, inc Rocketdyne, secured by MoU, 30/7/54.

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