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Author Topic: Rolls Royce Viper/ Bristol Siddeley Orpheus  (Read 24742 times)

Offline JFC Fuller

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #30 on: December 14, 2012, 05:19:35 am »
That Orpheus 12 with afterburning actually sounds like quite a missed opportunity.
 
I can actually think of quite a few aircraft that may have benefitted from an engine in that class.
 
Any idea what it's physical dimensions were?

It certainly would have been an interesting engine, as would a militarised supersonic version of the BS.75, in particular the various proposed Gnat derivatives could have benefited: http://www.secretprojects.co.uk/forum/index.php/topic,769.msg98808.html#msg98808 

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #31 on: December 14, 2012, 05:24:17 pm »
The BS 75 diameter was 34.4 vs 32.4 inches for Orpheus 3 or 4; length 89 vs 75.5 or 77.5 for Orpheus 3 or 4.
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you. - Paul MacCready, aeronautical engineer.

Offline tartle

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #32 on: January 04, 2014, 03:48:42 am »
On some research unrelated to the Pegasus jet engine (about the wartime development of Merlin) I have been reading 'Sydney Camm and the Hurricane' which has a chapter or two on later developments after piston engines. There is some interesting 'stuff' on early P1127 design development and below is a page with some GA's of what the aircraft looked like before they trousered the hot exhaust!
"... prototypes are a way of letting you think out loud. You want the right people to think aloud with you. - Paul MacCready, aeronautical engineer.

Offline Abraham Gubler

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #33 on: May 04, 2015, 03:53:08 am »
Just stumbled across the thread. Thanks a lot Tartle for the very informative posts about the Viper and Orpheus.
"There is a tendency in our planning to confuse the unfamiliar with the improbable." Thomas Schelling

Offline Apophenia

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #34 on: October 09, 2018, 02:44:08 pm »
That Orpheus 12 with afterburning actually sounds like quite a missed opportunity. ... Any idea what it's physical dimensions were?

I know kaiserbill's request was a long time ago, but Flight did publish the Orpheus 12's dimensions ...

Quote
Bristol Siddeley Orpheus BOr.12 Single-shaft turbojet. Multi-stage compressor, can-annular combustion chamber and single-stage  turbine. Overall diameter, 32.4 in; length, 98.325 in; dry weight, 1,100 lb: max rating. 6,810 lb dry. The BO.12SR gives 8,170 lb thrust with simple reheat.

Orpheus  BOr.3  Mk  803 (not  illustrated). Overall diameter, 32 4 in; length, 7S.45 in; weight, 825 lb; max rating, 5,000 lb at 10,000 r.p.m. (s.f.c., 1.06); max mass flow and pressure ratio, 84tb/sec and 4.4:1.

The BOr.12SR has a reheat system of a special simplified pattern, intended principally to provide increased  thrust for operations from poor airfields. Aircraft designed to use it are in various stages of development in France, India and Spain. There is also a non-reheat commercial variant, fitted with a two-position nozzle which in the closed position permits the take-off rating to be raised to 7,200 lb and at full area lowers the cruising consumption. Weight would be some 1,220 lb with full airline equipment.

Flight 18 March 1960, page 369
https://www.flightglobal.com/FlightPDFArchive/1960/1960%20-%200369.PDF

Offline kaiserbill

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Re: Rolls Royce Viper/ Bristol Siddeley Orpheus
« Reply #35 on: October 10, 2018, 06:25:02 am »
Thanks Apophenia!