peter kent
October 31, 2012, 21:58:00 GMT
permalink Post: 7496372

593 smoke reduction

ref question from Joliste

Quote:

why were the Olympus 593 s so smoky to start with, did they use excess fuel to help with cooling as some petrol engines do or was there some design feature which caused the smoke. It seeems to have been cured in later engines
rod

As I was working my way from 1 to 85 I read the above which reminded of a paper I filed 35 years ago:
"Development of Pollution Controls for Rolls-Royce RB211 and Olympus 593 Engines" by A B Wassall. I have picked out stuff relevant to the question:

The engines of the day generated smoke in the primary zone and partially consumed it in the rest of the combustor.
It was easier to reduce the production than increase the consumption but leaning the primary zone had an adverse effect on relight capability which then needed its own corrective action as was done on the 211. Metal temperatures went up with the leaning (as intimated by Joliste)
The 593 did not have the leaning option as it had to maintain an over-rich primary zone at TO to ensure an adequate weak extinction margin when throttled back at completion of supersonic cruise when the combustor had to operate at A/F ratios over 180.
In addition to the smoke problem the combustor weight and pressure loss had to be reduced.
These other two requirements led to the annular combustor and vaporizers which also reduced the smoke substantially. These three benefits were expected based on Pegasus experience.

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CliveL
February 23, 2013, 08:06:00 GMT
permalink Post: 7710332

Quote:

As a Chartered Engineer working on a multi-disciplinary rail project, I am amazed that a project as complex as this was managed across the Channel in the 1960's; how was the Systems Engineering managed - who drove the requirements for the Jet, potential carriers, engineers or politicians?

For sure not the politicians, who could not distinguish between their rectum and middle arm joint so far as aircraft systems were concerned

Once it was decided to go, I would say that the system requirements were largely driven by the difficulty of the task - more a question of finding out how to make it work than of optimising. The overall aircraft requirements were driven by the engineers, but criticised by the potential customer airlines in regular meetings.

Safety requirements were specified in a completely new airworthiness code - a sort of comprehensive set of special conditions, which were generally more severe than the subsonic codes of the time. Concorde, for example, was, AFAIK , the first civil aircraft to be certificated against the requirements that now exist as 25.1309.
But nobody really knew what to write for supersonic flight and, in particular, the transition from subsonic, so to some extent one made it up as one went along, using prudent common sense and engineering judgement. Fuel system transfer rates for example had to match a requirement that it should be possible to abandon the acceleration at any point and return safely to subsonic conditions - and the deceleration was much quicker than the acceleration!

Quote:

wind modelling played a big part in the development of the aerodynamics, how big did the models go? Did you have the luxury of testing a full-scale model? or maybe full-scale parts or sub assemblies?

Well some people might say we had four full scale models - two prototypes and two pre-production models

Supersonic testing mainly at 1/30 scale; low speed 1/18. The biggest model was a 1/6 scale half model used mainly for icing tests. Isolated intake tests, IIRC, about 1/10 scale, but we did have a full scale intake operating in front of an Olympus 593 at Mach 2.0 in Cell 4 at NGTE Pyestock.

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CliveL
October 23, 2013, 12:49:00 GMT
permalink Post: 8113333

Quote:

I know Concorde engines were FADEC. Were the Thrust levers gated like on Airbus? I noticesd cocncorde pilots shovved the levers forward for take off thrust..not the gentle easing forward like most other turbojets..why was there this need?Did they take too much time to spool up?

The engine was electrically signalled, but it wasn't FADEC; the control system(s) were analogue.
I suspect the zero bypass Ol 593 would take less time to spool up than todays high bypass engines.

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DonH
October 23, 2013, 13:20:00 GMT
permalink Post: 8113381

CliveL;
Re, "I suspect the zero bypass Ol 593 would take less time to spool up than todays high bypass engines. "
Yes, I think so. The A333 (RB211s) had a specific technique at high-altitude airports to ensure the engines were stabilized at about 1.1EPR before taking the thrust levers into the FLEX/MCT or TOGA detent. The thrust levers were taken to their detents 'gently', even as FADEC did control the acceleration. Even then, some surging was experienced, again at high-altitude airports, (CYYC for example).

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EASAPARTACADEMY
June 24, 2022, 23:14:00 GMT
permalink Post: 11251293

Quote:

Originally Posted by M2dude

Point taken GF, but it was discovered during development flying that that the Olympus 593 could be relit, given sufficient IAS, at almost any altitude within the normal flight envelope. The variable inlet would even be automatically scheduled, as a funcion of N1, in order to improve relight performance at lower Mach numbers. I certainly agree that you would decelerate and lose altitude fairly quickly under these conditions, however a multiple flame out was never experienced during the entire 34 years of Concorde flight testing and airline operation. There was, as a matter of interest an un-commanded deployment of a Concorde RAT AT MACH 2!! (The first indications of the event were when the cabin crew complained about 'a loud propeller sound under the rear cabin floor'. A quick scan of the F/E's panel revealed the truth of the matter). The aircraft landed at JFK without incident, and the RAT itself, apart from a very small leak on one of the hydraulic pumps, was more or less un-phased by the event. Although it sounds horrific, a prop rotating in a Mach 2 airstream, the IAS it 'felt' would be no more than 530 KTS at any time. The RAT was of course replaced before the aircraft flew back to LHR.
Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. Or do you mean the the F16 has an emergency power unit? Either way, it's fascinating stuff.
Yes, I do remember that the Germans used Hydrazine as a fuel during WW2: The father of one of our Concorde pilots was on an air raid to destroy one o the production plants there, this aviation business is such a small world.

Thanks for the reply, Concorde expertise is always interesting. I should not have called the F-16 Emergency Power Unit a RAT, it is indeed not. The Concorde RAT was located aft between the engine pods, correct?

What I found interesting is that the AC generators would remain on-line at all; they drop instantaneously at subsonic speeds and the associated N2 rpm. I believe the hydraulics on the 747 will power flight controls down to a pretty low IAS.

Four engine flameout is a very unlikely event, unless one runs into a volcanic cloud.

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fill_ot
November 01, 2023, 21:33:00 GMT
permalink Post: 11531535

Olympus 593 ECU PCB identification

This may be a bit of a long shot.
I am trying to identify the function of two printed circuit boards from an Olympus 593 Engine Engine Control Unit (ECU). I worked on Concorde and its ECUs at Filton for many years in the 1970s and 80s.
When Concorde retired in 2003 I requested from British Airways and was given 2 ECU PCBs as a souvenir.
There were of course 8 ECUs on each aircraft, 2 per engine. Each ECU had about 20 different PCBs. I have sometimes wondered just what the function was of my 2 PCBs. Maybe someone knows or has the relevant ECU Overhaul Manual. I have already asked various organisations for help - Ultra Electronics the manufacturers of the ECUs, British Airways, Rolls-Royce Heritage Trust and some museums. I've had some helpful replies but no actual answers.
Marked on the PCBs ae their drawing numbers: 46546-629-0 and 46456-602-0.
I have tried to attach some photos but there seems to be some forum setting that's preventing this!
Thanks

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Jhieminga
November 10, 2023, 07:35:00 GMT
permalink Post: 11536526

Quote:

Originally Posted by fill_ot

That's an interesting challenge, but one that is very hard to solve. Have you tried asking on the Concordesst.com website and their forum? As you say, you would need to find a very specific overhaul manual and I don't know if a manual like that is even around, other than in a heritage collection somewhere.

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Lawrence2725
November 26, 2023, 12:28:00 GMT
permalink Post: 11546244

Quote:

Originally Posted by fill_ot

Rolls Royce will hold a copy of the CMM for the ECU. Airbus probably do as well.

Whether either of them would release it to you, even now, I am doubtful.

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peter kent October 31, 2012, 21:58:00 GMT permalink Post: 7496372	593 smoke reduction ref question from Joliste Quote: why were the Olympus 593 s so smoky to start with, did they use excess fuel to help with cooling as some petrol engines do or was there some design feature which caused the smoke. It seeems to have been cured in later engines rod As I was working my way from 1 to 85 I read the above which reminded of a paper I filed 35 years ago: "Development of Pollution Controls for Rolls-Royce RB211 and Olympus 593 Engines" by A B Wassall. I have picked out stuff relevant to the question: The engines of the day generated smoke in the primary zone and partially consumed it in the rest of the combustor. It was easier to reduce the production than increase the consumption but leaning the primary zone had an adverse effect on relight capability which then needed its own corrective action as was done on the 211. Metal temperatures went up with the leaning (as intimated by Joliste) The 593 did not have the leaning option as it had to maintain an over-rich primary zone at TO to ensure an adequate weak extinction margin when throttled back at completion of supersonic cruise when the combustor had to operate at A/F ratios over 180. In addition to the smoke problem the combustor weight and pressure loss had to be reduced. These other two requirements led to the annular combustor and vaporizers which also reduced the smoke substantially. These three benefits were expected based on Pegasus experience. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
CliveL February 23, 2013, 08:06:00 GMT permalink Post: 7710332	Quote: As a Chartered Engineer working on a multi-disciplinary rail project, I am amazed that a project as complex as this was managed across the Channel in the 1960's; how was the Systems Engineering managed - who drove the requirements for the Jet, potential carriers, engineers or politicians? For sure not the politicians, who could not distinguish between their rectum and middle arm joint so far as aircraft systems were concerned Once it was decided to go, I would say that the system requirements were largely driven by the difficulty of the task - more a question of finding out how to make it work than of optimising. The overall aircraft requirements were driven by the engineers, but criticised by the potential customer airlines in regular meetings. Safety requirements were specified in a completely new airworthiness code - a sort of comprehensive set of special conditions, which were generally more severe than the subsonic codes of the time. Concorde, for example, was, AFAIK , the first civil aircraft to be certificated against the requirements that now exist as 25.1309. But nobody really knew what to write for supersonic flight and, in particular, the transition from subsonic, so to some extent one made it up as one went along, using prudent common sense and engineering judgement. Fuel system transfer rates for example had to match a requirement that it should be possible to abandon the acceleration at any point and return safely to subsonic conditions - and the deceleration was much quicker than the acceleration! Quote: wind modelling played a big part in the development of the aerodynamics, how big did the models go? Did you have the luxury of testing a full-scale model? or maybe full-scale parts or sub assemblies? Well some people might say we had four full scale models - two prototypes and two pre-production models Supersonic testing mainly at 1/30 scale; low speed 1/18. The biggest model was a 1/6 scale half model used mainly for icing tests. Isolated intake tests, IIRC, about 1/10 scale, but we did have a full scale intake operating in front of an Olympus 593 at Mach 2.0 in Cell 4 at NGTE Pyestock. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
CliveL October 23, 2013, 12:49:00 GMT permalink Post: 8113333	Quote: I know Concorde engines were FADEC. Were the Thrust levers gated like on Airbus? I noticesd cocncorde pilots shovved the levers forward for take off thrust..not the gentle easing forward like most other turbojets..why was there this need?Did they take too much time to spool up? The engine was electrically signalled, but it wasn't FADEC; the control system(s) were analogue. I suspect the zero bypass Ol 593 would take less time to spool up than todays high bypass engines. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
DonH October 23, 2013, 13:20:00 GMT permalink Post: 8113381	CliveL; Re, "I suspect the zero bypass Ol 593 would take less time to spool up than todays high bypass engines. " Yes, I think so. The A333 (RB211s) had a specific technique at high-altitude airports to ensure the engines were stabilized at about 1.1EPR before taking the thrust levers into the FLEX/MCT or TOGA detent. The thrust levers were taken to their detents 'gently', even as FADEC did control the acceleration. Even then, some surging was experienced, again at high-altitude airports, (CYYC for example). Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
EASAPARTACADEMY June 24, 2022, 23:14:00 GMT permalink Post: 11251293	Quote: Originally Posted by M2dude Point taken GF, but it was discovered during development flying that that the Olympus 593 could be relit, given sufficient IAS, at almost any altitude within the normal flight envelope. The variable inlet would even be automatically scheduled, as a funcion of N1, in order to improve relight performance at lower Mach numbers. I certainly agree that you would decelerate and lose altitude fairly quickly under these conditions, however a multiple flame out was never experienced during the entire 34 years of Concorde flight testing and airline operation. There was, as a matter of interest an un-commanded deployment of a Concorde RAT AT MACH 2!! (The first indications of the event were when the cabin crew complained about 'a loud propeller sound under the rear cabin floor'. A quick scan of the F/E's panel revealed the truth of the matter). The aircraft landed at JFK without incident, and the RAT itself, apart from a very small leak on one of the hydraulic pumps, was more or less un-phased by the event. Although it sounds horrific, a prop rotating in a Mach 2 airstream, the IAS it 'felt' would be no more than 530 KTS at any time. The RAT was of course replaced before the aircraft flew back to LHR. Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. Or do you mean the the F16 has an emergency power unit? Either way, it's fascinating stuff. Yes, I do remember that the Germans used Hydrazine as a fuel during WW2: The father of one of our Concorde pilots was on an air raid to destroy one o the production plants there, this aviation business is such a small world. Thanks for the reply, Concorde expertise is always interesting. I should not have called the F-16 Emergency Power Unit a RAT, it is indeed not. The Concorde RAT was located aft between the engine pods, correct? What I found interesting is that the AC generators would remain on-line at all; they drop instantaneously at subsonic speeds and the associated N2 rpm. I believe the hydraulics on the 747 will power flight controls down to a pretty low IAS. Four engine flameout is a very unlikely event, unless one runs into a volcanic cloud. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
fill_ot November 01, 2023, 21:33:00 GMT permalink Post: 11531535	Olympus 593 ECU PCB identification This may be a bit of a long shot. I am trying to identify the function of two printed circuit boards from an Olympus 593 Engine Engine Control Unit (ECU). I worked on Concorde and its ECUs at Filton for many years in the 1970s and 80s. When Concorde retired in 2003 I requested from British Airways and was given 2 ECU PCBs as a souvenir. There were of course 8 ECUs on each aircraft, 2 per engine. Each ECU had about 20 different PCBs. I have sometimes wondered just what the function was of my 2 PCBs. Maybe someone knows or has the relevant ECU Overhaul Manual. I have already asked various organisations for help - Ultra Electronics the manufacturers of the ECUs, British Airways, Rolls-Royce Heritage Trust and some museums. I've had some helpful replies but no actual answers. Marked on the PCBs ae their drawing numbers: 46546-629-0 and 46456-602-0. I have tried to attach some photos but there seems to be some forum setting that's preventing this! Thanks Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
Jhieminga November 10, 2023, 07:35:00 GMT permalink Post: 11536526	Quote: Originally Posted by fill_ot This may be a bit of a long shot. I am trying to identify the function of two printed circuit boards from an Olympus 593 Engine Engine Control Unit (ECU). I worked on Concorde and its ECUs at Filton for many years in the 1970s and 80s. When Concorde retired in 2003 I requested from British Airways and was given 2 ECU PCBs as a souvenir. There were of course 8 ECUs on each aircraft, 2 per engine. Each ECU had about 20 different PCBs. I have sometimes wondered just what the function was of my 2 PCBs. Maybe someone knows or has the relevant ECU Overhaul Manual. I have already asked various organisations for help - Ultra Electronics the manufacturers of the ECUs, British Airways, Rolls-Royce Heritage Trust and some museums. I've had some helpful replies but no actual answers. Marked on the PCBs ae their drawing numbers: 46546-629-0 and 46456-602-0. I have tried to attach some photos but there seems to be some forum setting that's preventing this! Thanks That's an interesting challenge, but one that is very hard to solve. Have you tried asking on the Concordesst.com website and their forum? As you say, you would need to find a very specific overhaul manual and I don't know if a manual like that is even around, other than in a heritage collection somewhere. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.
Lawrence2725 November 26, 2023, 12:28:00 GMT permalink Post: 11546244	Quote: Originally Posted by fill_ot This may be a bit of a long shot. I am trying to identify the function of two printed circuit boards from an Olympus 593 Engine Engine Control Unit (ECU). I worked on Concorde and its ECUs at Filton for many years in the 1970s and 80s. When Concorde retired in 2003 I requested from British Airways and was given 2 ECU PCBs as a souvenir. There were of course 8 ECUs on each aircraft, 2 per engine. Each ECU had about 20 different PCBs. I have sometimes wondered just what the function was of my 2 PCBs. Maybe someone knows or has the relevant ECU Overhaul Manual. I have already asked various organisations for help - Ultra Electronics the manufacturers of the ECUs, British Airways, Rolls-Royce Heritage Trust and some museums. I've had some helpful replies but no actual answers. Marked on the PCBs ae their drawing numbers: 46546-629-0 and 46456-602-0. I have tried to attach some photos but there seems to be some forum setting that's preventing this! Thanks Rolls Royce will hold a copy of the CMM for the ECU. Airbus probably do as well. Whether either of them would release it to you, even now, I am doubtful. Reply to this quoting this original post. You need to be logged in. Not available on closed threads.

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