Technical Talk

[Engine 711]

A late friend of mine worked at BS in the sixties. He had this to say about XM691
It would be silly to say that I knew XM691 well, but it feels like it. It was used by Bristol Siddeley not only for flight test, but also a chase plane, for observation and for photography. The in-flight photograph of the Valiant, used briefly as Pegasus test bed, was probably taken from it.
In 1964 or thereabouts, in the course of my apprenticeship, I spent two weeks in the Flight Shed, and XM691 was there. It was much used and much liked.
Pegasus of course had its origins in the Orpheus, later powered the Harrier.

Interesting insight - so XM691 was a Flight Test aircraft...?

According to Stanley Hooker's book, the Pegasus began as an amalgam of an Olympus LP (as the fan) and an Orpheus (as the core or HP).

[Richie]

Mtskull- to answer your question, yes it works and works fine without the accumulator, however in the event of a flame out, Ted / Stew must ensure they deploy the brake ram before the engine spools down and stops spinning.

Post Bute I will pull the thing back out of the bilges and thoroughly investigate !

At the moment it is the weak link in the system, which thankfully after much running seems ok at present (however I have said it now haven’t I)

[conistoncollie]

According to Stanley Hooker's book, the Pegasus began as an amalgam of an Olympus LP (as the fan) and an Orpheus (as the core or HP).

Engine 711 - I am enjoying reading your technical questions and feedback. Indeed it did. Prior to the Orpheus they used two compressors of the Orion which made it too long. The Orpheus itself used the low pressure spool of the Orion. The full story is beautifully and intimately described in my late colleague's book 'Pegasus The Heart of the Harrier'. Written with the clear insight that comes from being responsible for the engine's commercial fortunes for 16 years.

[Engine 711]

Engine 711 - I am enjoying reading your technical questions and feedback. Indeed it did. Prior to the Orpheus they used two compressors of the Orion which made it too long. The Orpheus itself used the low pressure spool of the Orion. The full story is beautifully and intimately described in my late colleague's book 'Pegasus The Heart of the Harrier'. Written with the clear insight that comes from being responsible for the engine's commercial fortunes for 16 years.

@conistoncollie - Thank you. I am ex-RR - mainly Marine - so Olympus, Tyne & Spey - for various Frigates & Destroyers, UK & overseas. Only did about 30 knots, but.... they were over 5000 tonnes.....

Can definitely recommend the book 'Not Much of an Engineer' - by (Sir) Stanley Hooker - which covers a lot of the Bristol engines, including Oly, Pegasus, Orpheus and more - Oly for TSR2, Oly 593 for Concorde, etc. Am sure the Orion got a mention, too.

https://www.amazon.co.uk/Not-Much-Engin ... 1853102857

Hmm... cheaper than the Pegasus book..... lols.

https://www.google.co.uk/shopping/produ ... CNsQ6SQIZg

[rich1608]

@conistoncollie - Thank you. I am ex-RR - mainly Marine - so Olympus, Tyne & Spey - for various Frigates & Destroyers, UK & overseas. Only did about 30 knots, but.... they were over 5000 tonnes.....

Did you have any involvement with the RR/BS Marine Proteus engine used in the giant SR-N4 hovercraft? And of course in non-marine guise in Donald's CN7 land speed record breaker.

[Engine 711]

Did you have any involvement with the RR/BS Marine Proteus engine used in the giant SR-N4 hovercraft? And of course in non-marine guise in Donald's CN7 land speed record breaker.

The Marine Proteus was still around, in my early days - I didnt work on it, but I knew people who did. Used in the SRN4 hovercraft and also in various Fast Patrol/Torpedo boats.

DMC's CN7 Proteus was I believe a modified Aero Proteus - effectively a Brittania engine, modified to drive from both ends.

[Renegadenemo]

First time I went to Derby there was a Proteus in a big blue caravan like thing on the lawn with a huge cable snaking away from it. It was a generating set that supplied power to the offices. Maybe it's still there.

[Engine 711]

First time I went to Derby there was a Proteus in a big blue caravan like thing on the lawn with a huge cable snaking away from it. It was a generating set that supplied power to the offices. Maybe it's still there.

There was a Mobile Industrial Proteus gen set, which was in a artic trailer - and they were originally in Bristol Siddeley Blue - which is a dark blue (probably a few shades darker than Bluebird Blue...). Not many of them left now. Used to be 2 at Ansty - but one was sold on Wylfa Nuclear Power Station - because the 4 Proteus they had (in buildings) were not enough power - they needed more. That left just one at Ansty (*), still in its trailer - but now painted RR I&M White.

Not aware of any at Derby - or any that are still active or mobile, now.

(* - The Ansty one was supposed to keep the site going, in the event of power cuts - and also in modern times, to allow power from the grid to be reduced - and save money. On one occasion when there was a power cut, right in the middle of the day,we waited and waited for the Prot to start & the lights to come back on. And we waited...... Turns out, as a money saving measure during its most recent refurb, its Black Start batteries were removed - too expensive to replace - and replaced with power from the incoming grid supply...... See he problem....? )

[rich1608]

There were permanent Proteus generators for the national grid as well https://youtu.be/-kzvfXTpwUs
One of them has been preserved at the Museum of Internal Fire in Wales https://youtu.be/JAuTkPj-LG0

[midlife]

Being a current RR employee, I had to read the post out abut the Ansty generator, there are people in the office rolling round with tears in their eyes, strangely enough no one was surprised
Cheers
Wayne