De Havilland Gyron Engine

overscan (PaulMM)

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An interesting engine design. Can anyone add some more info?


From Wikipaedia:

De Havilland Gyron


The PS.23 or PS.52 Gyron, also known as the Halford H-4, was Frank Halford's last turbojet design while working for de Havilland. Intended to outpower any design then under construction, the Gyron was the most powerful engine of its era, producing 20,000 lbf "dry", and 27,000 lbf with afterburner ("reheat" in British terminology). The engine was actually too large for most roles and saw no production use. It was later scaled down to 45% of its original size to produce the de Havilland Gyron Junior, which was somewhat more successful.

The Gyron was Halford's first axial-flow design, a complete departure from his earlier centrifugal-flow engines based on Whittle-like designs, the Goblin (H-1) and Ghost (H-2). The Gyron was also one of the first engines designed specifically for supersonic flight.

The Gyron first ran in 1953. Flight testing started in 1955 on a specially modified Short Sperrin bomber, replacing the lower two Rolls-Royce Avons with the much larger Gyrons.

The Gyron was selected for a number of projects, most notably the Hawker P.1121 (sometimes referred to as the Hurricane) supersonic attack aircraft that was to have been the replacement for the Hawker Hunter. However, this project was eventually cancelled.

Variants, from www.skomer.u-net.com

PS.26
De Havilland H.4 Gyron turbojet
Intended for Hawker P.1121
Rated at 20000lb / 27000lb (88.9 / 120.1KN).

PS.48
De Havilland Gyron turbojet
Intended for OR.330 aircraft.
Rated at 18510lb (82.3KN).

PS.52
Development of De Havilland Gyron turbojet.
2 x intended for Saro P.187 interceptor to F.155 / OR.329.
Rated at 25000lb / 35000lb (111.2 / 155.7KN).

PS.55
Development of De Havilland Gyron turbojet.
2 x intended for Vickers / EE Type 571 to meet OR.343.
Rated at 25000lb / 35000lb (111.2 / 155.7KN).
 
Here is a cutaway drawing from a 1958 Air Pictorial:
 

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Reference to investigate

Douglas R. Taylor: Boxkite to jet: the remarkable career of Frank B Halford. Derby: Rolls Royce Heritage Trust, 1999 ISBN 1-872922-16-3 (Rolls Royce Heritage Trust. Historical series; no. 28)
 

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National Archives

AVIA 54/1359
AVIA 65/13
AVIA 28/330
AVIA 28/354
AVIA 28/368
AVIA 28/641
 
Thanks to Chris Gibson for this:

First flight of the Gyron - DH Gazette Aug 1955
The Gyron - DH Gazette Aug 1957
The Gyron - the most powerful jet engine in the world DH Gazette Oct 1955
The Gyron Gynorm - DH Gazette Dec 1957
The Gyron testbed - DH Gazette Oct 1955
 
Gyron engine, from De Havilland Heritage Centre. Funnily enough it looks exactly like the Gyron Junior, but much bigger.
 

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Here is some more info on the Gyron from Paul H. Wilkinson's Aircraft Engines of the World 1958/59.
 

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overscan said:
Funnily enough it looks exactly like the Gyron Junior, but much bigger.

That is why it is called the 'Junior'. The latter was a 0.45 scale version of the Gyron, initially at least. It later got an additional compressor stage with variable stators (also planned for some full size Gyrons, and possibly run, see my notes pdf) plus bleed ports for flap blowing etc, so evolved along its own lines, and into different versions (Buccaneer dry, SR.177 with reheat).

There were also some problems caused by the scaling down process, which 'scaled up' some problems.
 
Just checking!

I think the final Junior was fairly different from the early ones (PS.43/PS.50? IIRC), as correcting the problems/adapting to aircraft installations etc. led to many mods - the Junior was a production item and the 'senior' never got that far.

One thing I do not have clear is whether the Junior intended for the P.177 was run behind an inlet, and if so, was it stable? Presumably they would have run one like that (it was usual). If there were no problems, perhaps it was the P.1121 intake design that was at fault?
 
In a simple static test, yes. But Ralph Hooper and others thought that this could be misleading when extrapolated up to Mach 2.5. Using a split inlet for a single engine could have caused all sorts of sideslip related issues etc.
 
That is indeed a possible problem. I didn't see P.1121 as a particularly agile design, however.

If the mission becomes dedicated strike, with a Conway engine for example, I can't see it exceeding Mach 2, and a simple pitot intake might suffice. Whether that is an option in the speed obsessed era of 1959, I don't know however.
 
AVIA 54/1359 De Havilland H.4 engine, 'Gyron' development: policy

1948
  • Earliest H4 scheme is a 2 spool bypass design
  • NGTE 109 compressors, first one with two stages removed. Overall pressure ratio 9.3. Thrust 9-10,000lb static SL with SFC 0.75-0.79
  • 4/6/1/2 config
  • UK Government think De Havilland are out of their depth - they are small engine makers. General feeling that De Havilland should stick to that niche.
  • Itr doesn't help that engine design is highly criticised by government scientific advisers. SFC figures don’t add up - calculated to be nearer 1.0 than 0.75. De Havilland’s lack of axial experience cited as a major concern.

1951
PS.16 Gyron
5:1 Pressure ratio at SL. Rising to 12:1 at height with ram air compression in inlet.

1953
General Electric highly interested in licensing the design - De Havilland had to apply to allow details to be transferred. De Havilland have generated £21m in engine sales giving £1m in royalties to the government. Seriously proposed for CF-105 in competition with Curtiss-Wright J67 and Orenda.

Frank Halford says in a letter to the air ministry that new version more suitable to civil/bomber application will be forthcoming (bypass version)
 
Back in the dim and distant, I worked on a duplex control system for what I remember as the PS50 engine. My interest lay only in the electronics and the, then, revolutionary fibre optic communication between the two computers. The project was a collaboration between Smiths Industries and Dowty. A company was formed titled Dowty Smitns Industries Controls - DSIC.

I thought the engine was targeted at the Bristol T188 but a recent visit to RAF Cosford has proved that to be incorrect. A glance at the nacelles proved they were inappropriate. Furthermore, I understood that the engine was designed for Mach 3 which was greater than even the theoretical maximum of the T188. I believe it was triple spool.

A very helpful volunteer at Cosford discovered that RR used PS as a label for various engines but the latest one he found was, I think, the Olympus PS43.

Can anyone add any details for this project please?
 
Back in the dim and distant, I worked on a duplex control system for what I remember as the PS50 engine. My interest lay only in the electronics and the, then, revolutionary fibre optic communication between the two computers. The project was a collaboration between Smiths Industries and Dowty. A company was formed titled Dowty Smitns Industries Controls - DSIC.

I thought the engine was targeted at the Bristol T188 but a recent visit to RAF Cosford has proved that to be incorrect. A glance at the nacelles proved they were inappropriate. Furthermore, I understood that the engine was designed for Mach 3 which was greater than even the theoretical maximum of the T188. I believe it was triple spool.

A very helpful volunteer at Cosford discovered that RR used PS as a label for various engines but the latest one he found was, I think, the Olympus PS43.

Can anyone add any details for this project please?
PS.50 was the de Havilland Gyron Junior, and indeed intended for the Bristol Type 188. The 188 was supposed to reach at least Mach 2.5 but was rather a failure.

It was built, and used on the first Blackburn Buccaneers. The P.S. designations are de Havilland. Gyron (the big version) was PS.23.
 
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That was a rapid reply if ever there was one!

It was a long time ago. I have read what I could find about the PS50 but it does't accord with my (fuddled) memory. I thought it was a triple spool engine (whatever that means!).

However, the fact that it was reduced in size to become the Junior, allows me to understand the problem with the nacelle size. The engine was tested in the Dowty facility at Staverton airport. The control equipment was housed in a heavily protected overhead chamber. It fascinated me to observe an engineer wandering round the engine under power with an oilcan in his hand!
 
Triple spool means an engine with three separate, nested, rotating shafts, each with compressor blades at the front and turbine blades at the rear. It wasn't triple spool, the first such design was the RB.211 in the late 60s/early 70s. The idea was to run the three sets of compressor blades ( LP (low pressure compressor), IP (intermediate compressor) and HP (high pressure compressor) at different, optimal speed. Its complicated, and most modern engines settle for just two spools (LP/HP).

The various Gyrons were all single spool with just one set of compressors and turbines on a single shaft. They were simple in design and were intended for supersonic flight (up to about Mach 2.5). The large Gyron never made it to production and the Gyron Junior did not have a long career, as it was replaced on the Buccaneer by the Spey.

There was also a later big Gyron design called PS.52 but that remained on paper.
 
Back in the dim and distant, I worked on a duplex control system for what I remember as the PS50 engine. My interest lay only in the electronics and the, then, revolutionary fibre optic communication between the two computers. The project was a collaboration between Smiths Industries and Dowty. A company was formed titled Dowty Smitns Industries Controls - DSIC.

I thought the engine was targeted at the Bristol T188 but a recent visit to RAF Cosford has proved that to be incorrect. A glance at the nacelles proved they were inappropriate. Furthermore, I understood that the engine was designed for Mach 3 which was greater than even the theoretical maximum of the T188. I believe it was triple spool.

A very helpful volunteer at Cosford discovered that RR used PS as a label for various engines but the latest one he found was, I think, the Olympus PS43.

Can anyone add any details for this project please?
As previously mentioned the PS 50 was the Gyron Junior as fitted in the 188. Your engine, the original "big" Gyron, first ran at DeHavilland Hatfield in January 1953, also flight-tested in the Short Sperrin starting July 1955. This engine was for up to Mach 3 and much bigger than the PS 50. Was intended for Avro 730 supersonic bomber and Hawker P1121 interceptor. Demonstrated 29,000 lb thrust by the time worked ceased on it in 1958. ie twice that from the engine that fitted in the 188 nacelle, ie 14,000 lb.

Why was your duplex control system so named?

Cheers.
p.s. You can normally find a very detailed description of this engine on the Flightglobalarchive website, ie Flight magazine "Gyron" article, 2 August 1957. The site is temporarily down for upgrade.
 
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Slightly OT, but if I have this correctly ...

P.S.23 = Originally Halford H-4

P.S.26 = Gyron D.Gy.1 and D.Gy.2 (P.S.26-1, P.S.26-3, and P.S.26-6)

P.S.37 = (Project) Becomes Gyron Junior

P.S.43 = Gyron Junior DGJ.1
-- Also DGJ.2, DGJ.4, and DGJ.10?

P.S.50 = Gyron Junior DGJ.10R (Reheat, for Bristol 188)
-- Also DGJ.20? (FLight also mentioned a 1961 DGJ.101)

P.S.52 = (Project) 'Big' Gyron D.Gy.?

PS.53 - Gyron Junior DGJ.?
 
I would be surprised if the T188 had any fibre optics, I remember a hearing a story of guys working on it having to wear rubber boots to prevent electric shocks from the HT lines of the thermionic valves. I believe fibre optics data transmission needs lasers diode which really didn’t make it out of the lab until well after the T188 was done and dusted

BTW I’ve seen T188 performance documents which suggests it’s positive stability margin was “better than Mach 2.8” and was optimistic that flight tests maybe able to demonstrate Mach 3 (windscreen limit). Of course intake control problems limited the max demonstrated speed to Mach 1.88. Sometime after the project was over it was discovered the intake control pressure transducers had been qualified to the wrong operating conditions. The supersonic thermal soak was only a fairly modest 8- 15 minutes depending on speed, just long enough to achieve thermal stability. Of course they didn’t get there due to high fuel consumption;- DH had lost interest in this engine, most of the technical team had left so the fine tuning of the performance just didn’t happen.

In the mid 90’s I regularly flew on a BAC 111 which had what was claimed to have the worlds first fly by light signalled secondary flight controls;- one set of spoilers. This claim was written on the side of the fuselage.
 
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Yes, that and the three spool description lead me to believe that the PS50 here is not the Gyron engine at all but a different engine project, maybe from the 1970s or something. What time frame are we talking about here?
 
I would be surprised if the T188 had any fibre optics, I remember a hearing a story of guys working on it having to wear rubber boots to prevent electric shocks from the HT lines of the thermionic valves. I believe fibre optics data transmission needs lasers diode which really didn’t make it out of the lab until well after the T188 was done and dusted

BTW I’ve seen T188 performance documents which suggests it’s positive stability margin was “better than Mach 2.8” and was optimistic that flight tests maybe able to demonstrate Mach 3 (windscreen limit). Of course intake control problems limited the max demonstrated speed to Mach 1.88. Sometime after the project was over it was discovered the intake control pressure transducers had been qualified to the wrong operating conditions. The supersonic thermal soak was only a fairly modest 8- 15 minutes depending on speed, just long enough to achieve thermal stability. Of course they didn’t get there due to high fuel consumption;- DH had lost interest in this engine, most of the technical team had left so the fine tuning of the performance just didn’t happen.

In the mid 90’s I regularly flew on a BAC 111 which had what was claimed to have the worlds first fly by light signalled secondary flight controls;- one set of spoilers. This claim was written on the side of the fuselage.
If this is right it puts the failure of the T.188 into a different light.
A failure to actually tune the systems to get most out of it
 
Yes, that and the three spool description lead me to believe that the PS50 here is not the Gyron engine at all but a different engine project, maybe from the 1970s or something. What time frame are we talking about here?
The project was a collaboration between Smiths Industries and Dowty. A company was formed titled Dowty Smitns Industries Controls - DSIC.

DSIC were formed to build the digital engine control for the Pegasus 11. They trialled it on a Gyron Junior. https://books.google.co.uk/books?id...w#v=onepage&q=dowty decs gyron junior&f=false
 
Dowty Smiths Industries Controls was not formed until 1977 but both companies had been active in research into fibre optics before that. An interesting brochure on DSIC's work can be found here.
 
BTW I’ve seen T188 performance documents which suggests it’s positive stability margin was “better than Mach 2.8” and was optimistic that flight tests maybe able to demonstrate Mach 3 (windscreen limit). Of course intake control problems limited the max demonstrated speed to Mach 1.88. Sometime after the project was over it was discovered the intake control pressure transducers had been qualified to the wrong operating conditions. The supersonic thermal soak was only a fairly modest 8- 15 minutes depending on speed, just long enough to achieve thermal stability. Of course they didn’t get there due to high fuel consumption;- DH had lost interest in this engine, most of the technical team had left so the fine tuning of the performance just didn’t happen.
If this is right it puts the failure of the T.188 into a different light.
A failure to actually tune the systems to get most out of it

It sure is correct, although I have heard a former DH guy saying the high fuel consumption was a result of poor intake/engine matching. I’ve seen a costed proposal document for fitting one of the T188 with a Buccaneer S1 retractable air to air refuelling probe which was another way of addressing the endurance problem;- of course never followed through.

But remember even if this had fixed the endurance problem, the T188 was still over weight, over budget, late/dragging on, a cul-de-sac in terms of airframe technology and its intakes were not representative of Concorde or even working during flight testing I.e subject to persistent unstarts..... as per the A12 at approx the same timeframe.......lots of reasons to stop.

That said the chaps at Filton learnt a awful lot from this program.
 
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Well yes, once the F.177 was cancelled supersonic Gyron Junior was only for the T.188 and Gyron Junior was flawed for the Buccaneer as it turned out, thanks to a rubber ball valve....
 
ref the t188 intake centrebody:
Gunston's Flight article 3 May 1962 said it was fixed (at that time).
His book "Back to the drawing board" (1996) says it was moveable.

I see mention of intake control pressure transducers above (Apr 8 2020). Were they used for positioning the spike or controlling the spill valves downstream of the throat (as shown in Flight article)? Thanks
 
The first and second aircraft had quite a few differences, with the second being more sophisticated. The first one had fixed intakes/simple spill door operation and I can’t remember if the second had translating aerospikes but it certainly had an intake control system. The problem with the qualification of the intake transducer related to the control of the spill doors.
 
The first and second aircraft had quite a few differences, with the second being more sophisticated. The first one had fixed intakes/simple spill door operation and I can’t remember if the second had translating aerospikes but it certainly had an intake control system. The problem with the qualification of the intake transducer related to the control of the spill doors.
Thanks for that. Gunston's book says they were translating but I haven't found any mention of that anywhere else, that's why I was curious for any further confirmation.
 
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Article, including a zoom-in on the propulsion system diagram, attached as images for ease of viewing and to ensure we don't lose it. Very interesting article, I recall seeing a very similar one in the now defunct Flight Archive.
 

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I merged two Gyron topics together with a topic in a non-public area and so it was inaccessible. Fixed!

I'd reread the entire thread as there are posts that were not previously public now visible.
 

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