Posts by user "M2dude" [Posts: 257 Total up-votes: 1 Page: 9 of 13]¶

Mr Vortex
Finally as promised, here is a schematic of the AFT part of the fuel vent system. As you can tsee the fin intake pressurises the air space above tank 11, and hence, via the Scavenge Tank air-space, the remaining tanks. (Also you can see the Trim Pipe Drain Vaves you were asking about.



Regards Dude

howiehowie93
Welcome aboard and thank you for your kind words; I am so glad you enjoy our thread. You are in good company here also, many of the 'more mature' vintage Concorde people (like me) are ex-RAF. (And some of the pilots were ex-RN also, but no one is perfect ... only joking guys).
It is a matter of pride/embarrassment for me that up to the end of 2003, I'd only ever really 'known' two aircraft; the C-130 and Concorde .
I was really interested in some of the RB199/Olympus similarities; TBP was tried on the development aircraft for engine control TET calculation, but Rolls-Royce were unhappy with the performance and abandoned TBP in favour of indirectly computing TET as a function of T1 (intake TAT) and EGT (T7). (And this meant the removal of the four TBP amplifiers too... we had even more black boxes then.
As for the three 'control amps' you were speaking of, I'm 99% sure that A/C 101, G-AXDN still does have the units you described fitted. The ECUs (or ECAs as they were sometimes called) were a highly complex analog control unit built by Ultra Electronics. They could be quite a headache sometimes in terms of reliability, but would generally perform flawlessly in terms of engine control. As with any analog box, control law changes in the field were not too straightforward and a soldering iron was the flight test engineers best friend here. The Reheat Amp was built by ELECMA (the electronics arm of SNECMA) and unlike some of the other components in the reheat system, was a beautifully designed and constructed unit. Very few reheat failures (and there were many) were attributed to the 'box' itself. The main fragility with the reheat system was the ignition system used (a 20 KV swirl ignitor, which you will see is covered previously in the thread). We (BA/RR) were seriously looking at one point of investigatng the use of 'hot streak' injection as a backup ignition source, which I believe was used in the 199 (?), but it unfortunately never happened. The Plessey DECU that was tried on A/C 202 (G-BBDG) DID combine main engine control and reheat, but unfortunately was never taken up for the production A/C, and so we were left withe the '3 AMPS' as you so eloquently describe. We had a total of THIRTY ONE control units associated with powerplant control on Concorde; might be a little different now methinks ]
Thanks for some of the fascinating engine history snippets you shared with us, although purists might regard it as being 'off topic' I personally think this rather unique thread is all the better for your contribution here,
I think it is great that you are working with industrial Olympuses, all part of the family tree. I will dig out the verboten sustained N1 speed band for the 593, it certainly WAS a fact though.
Thanks from all of us for your contribution here Howie, keep on posting.

Regards
Dude

howiehowie93
The whole idea of adapting hotstreak injection came from our Rolls-Royce rep', who spent many years on RB199 development. We'd even identified the position on the Olympus 593 for the injector itself; un unused start atomiser port, but as I reluctantly said before, it was not to be.
Apart from ignition issues the other main problems were reheat instability and reheat 'coming in with a thump', this particular malady being generally confined to transonic acceleration and not take-off.
The instability issue was caused by either an open circuit/high resistance fuel metering valve tacho (only rate feedback was used here) or more commonly contamination of the RFCU umbilical electrical connector. The connector itself was originally located high up the side of the engine, close to the combustion area, was barely accessable and was a total nightmare in terms of reliability. After a great deal of pressure from us (BA) SNECMA agreed to effectively relocate the connector at the bottom of the engine and the majority of our stability problems almost disapperared overnight.
The 'reheat in with a thump issue was a real beaut'. For transonic acceleration a much lower ratio of Fr/Fe (reheat fuel flow/engine fuel flow) was used than for take-off. (0.45 as opposed to 0.78) and therefore the opening rate of the fuel metering valve required damping, this being achieved by using a metered orifice inside the RFCU that applied a small amount of servo fuel pressure to one side of the valve to achieve the damping. Trouble was, any contaminants in the reheat fuel system would progressively clog up the orifice and kill our daming stone dead; the end result being the FMV banging wide open and hence the 'thump'. The only remedy for this problem was to replace the RFCU. SNECMA, in a truly classic feat of engineering produced a filter across this orifice, in order to prevent it getting clogged. Anyone see a problem with this? Yep, the filter itself would clog up and we got our beloved thump back. The only remedy for this problem was again to replace the RFCU. The contaminants were often as a result of RFCU build issues; this issue was never truly resolved.
I checked and found the dodgy sustained N1 band for the Olympus 593, this was 88-91% N1. This figure was never an issue in service as at cruise ISA -7 and above conditions the N1 was always run at the flat rate limit of 101.5%. Below ISA -7 the intake system would progressively reduce N1 as a function of intake local Mach Number, falling to 97.4% at ISA -24. (The coldest cruise conditions I personally ever saw was ISA - 25 (that's -81.5 degrees C folks) between BAH and BKK.
The controlled N1 at all other 'non cruise' phases was always in the upper 90's, well away from our blade resonance area.

jodeliste and Alpine Flyer
Thank you both for the TSR-2 information, it makes amazing reading (what a truly magnificent aircraft) , and as Concorde's military cousin, discussion here is in my opinion most waranted.

Regards
Dude

Bellerophon
Ahhh this 'other operator' (I'd quite forgotten our code for *** ******). And as for this obviously baseless story .... er yes it did happen. I should really have qualified my post and said 'The controlled N1 as long as the aeroplane was operated CORRECTLY was always at least in the upper 90's, well away from our blade resonance area'. I don't quite recall after the engines were removed post-flight (At Rolls-Royce's insistance) whether the entire LP compressor sections or just the first few stages had to be replaced at the engine overhaul base. In either case it was a rather expensive piece of experimentation.

ChristiaanJ
Certainly my friend (but hey, remember that I'm an old Volts and Amps and Ohms ancient at heart too ).
The lighting of a reheat flame can be achieved in three ways:
1) By using an electric arc ignitor.. the least reliable system, although relatively simple in concept.
2) Catalytic ignition, where the reheat fuel is sprayed over a platinum based catalyst, spontaneously igniting. I recall that although generally reliable, eventually the catalyst compound erodes away and you are left with no ignition source.
3) Hot streak injection (or ignition). I this case a sizable jet of fuel is injected through a single injector placed the the combustion chamber of the engine, a powerful streak of flame then 'shoots out' of the turbine, and ignites the reheat fuel. Generally reliable as long as the injector itself does not carbon up (as our new friend Howiehowie93 pointed out). What amazed me with this system when we were looking at it for Concorde, was that the Olympus 593 designer I spoke to at Rolls-Royce told me that it has a negligible effect on turbine blade life, as the hottest part of the flame does not hit the blades themselves, and also of course it is a very short duration burn anyway (1 - 2 seconds).
And Christian my friend, you should indeed 'rabbit on' here about some of your observations regarding Concorde electronics technology, you have a unique insight here as (probably) the only Concorde systems designer that regularly visits 'here'. I'm sure I speak for many of us here when I say that your experiences are unique and your contributaions are always illuminating. Come on, let's have some Volts/Amps and Ohms

Best Regards
Dude

Landroger
The great thing about the OLY593 was the high specific thrust (in relative terms the Olympus is a tiny, compact design), it's growth potential/high potential mass flow. A bypass engine is not really ideal for supersonic cruise, and given what was available in terms of two-spool turbojets in the 1960s, the Olympus was the obvious choice for both the TSR-2 and Concorde alike. As far as for ships and power stations, well a turbojet is always going to be favourite, as all the gas energy is contained in the jet efflux; this can be efficiently transferred to the load in question by a gearbox coupled to the HP spool.

howiehowie93
Well the 593 did require a primary nozzle to match N1 against N2, bur apart from that she was a study of deceptive simplicity and elegance.
No mate, generally BI-HEX AF.
This really is fascinating stuff Howie, thank you. As I alluded to a few pages back, the primary nozzle on the OLY593 opened in response to the rising P7, kind of 'after the horse has bolted' in a way. To maintain the correct scheduled value of N1, the control system set, via a needle valve, a finite ratio between P7 and P3. As reheat lit as P7 attempted to rise it upset this ratio and the primary nozzle was opened in order to restore the aforementioned ratio. (Nozzle opens, P7 falls). When reheat was cancelled the opposite happened, and the nozzle closed sharply to prevent N1 overspeed.

Tom355UK
Glad you are enjoying our thread, and thank you for your kind words. (But apologies to your good lady wife though ).
Jeepers Tom that is one hell of a question. Assuming there was a market for such a venture (personally not sure right now) I think you are looking at BILLIONS of $, and for this reason alone I think you'd find that a multi-national/continental effort would be required. There is little doubt that technology is not the major barrier here, but economics and political will. (Nice thought though, I do agree).
As far as a powerplant goes, well the PW5000 is a really superb engine, although well down on the thrust requirement for an 'NG' SST. More likely I would have thought would be e development of the Olympus, there was/is still such an enormous amount of potential in this basic design. (But who knows, this is all pure speculation anyway).
And have no fears about posting here Tom, most of us are quite happy to answer away (We've said before that there is no such thing as a stupid question; you are most welcome here ).

DavvaP It really did not matter what airframe we used for the test flight; the sole purpose was just to find out just what effect (if any) the tank liners had on the performance of the fuel system. (The handsome chap who you see on TV most, installing the liners, Mr Marc Morley left BA and now resides in Australia).
I am honoured to say that I was lucky enough to be onboard G-BOAF for that flight from LHR-BZZ and as far as I could tell, the liners had no impact whatsoever. One amusing part of the flight was when we deliberately allowed tank 3 to run dry and see just what the indicated fuel quantity was as #3 engine flamed out (we were subsonic at this point of course). The gauge slowly crept down (in order for the tank to to run dry, the tank 7 & 8 transfer pumps were switched off) and we all watched in eager anticipation/dread....... as the counters reached zero weeeeeee... the engine flamed out. I am being completely honest here, the engine wound down EXACTLY at ZERO indicated contents).
Those 7 aircraft really did look magnificent I know, it was just sad as to the reason they were all lined up there.

Mr.Vortex
Well she was a delta without a tailplane, so the short answer is 'yes', but remember that we used fuel to move the CG backwards and forwards for long term trimming.
OK, this is a little complicated, so bear with me. The intake had a finite limit, in terms of the mass flow that it could deliver to the engine and so an automatic N1 limitation signal was transmitted from the intake 'box' (the AICU) to the engine 'box' (the ECU) full time above Mach 1.6. Now this limitation was referenced against TEMPERATURE compensated N1, ( N1/ \xd6 q) and at normal ISA temperatures this limit was above the 'normal' 101.5% N1 running line. (The lower the temperature, the lower the effective limit became). At ISA -7 the limit now became less than 101.5% N1, and so the demanded value of N1 was reduced to this value. But this limit signal was always there, it's just that at normal temperatures it was effectively ignored by the ECU. If this limitation signal failed for any reason, the AICU would detect this by way of the ramp angle becoming uncomfortably close to it's MINIMUM variable limit (this limit was scheduled as a function of intake local Mach number) and an amber light would illuminate on the associated N1 gauge, along with an amber INTAKE master warning would illuminate (plus an audible 'BONG' from the audio warning system). The only course of action was to manually reduce throttle setting away from the Mach 2 norm of maximum, in order to reduce N2, and consequently N1 and mass flow demand. There was in intake pressure ratio indicator at the top of the intake control panel that would show where the power setting would have to be set to. It was an indirect indication of intake shock geometry.
This manual N1 datum reset control was only used during flight test trials into just how much N1 would have to be controlled/reduced at low temperatures in order to give optimim intake geometry. It had absolutely nothing to do with afterburner/reheat and had no place in the production aircraft as all the research was complete

Best regards to all
Dude

Thanks Howie ('sir' my armpit ). The great part about this forum is that we can all (especially me) live and learn.
I humbly stand corrected and as always am thankful for your posts. (See, you've become a Concorder Howie )

Best regards
Dude

Glad you are enjoying your reads so far Keith, and welcome aboard; you are most welcome here. Anything you want some clarification about (especially my ramblings) or any new questions, well please feel free to fire away and ask. (8 pages so far eh? Jeepers, you've a lot of reading ahead of you ).

Best regards
Dude

Hi Guys, quite a few little points here, so here's my angle(s):
Pedalz
Ooo yes. The biggest problems we ever had associated with the ramps themselves were wear in the seals at the sides of the forward ramp. Even a few thou' over the maximum allowable side gap was enough to make the intake unstable and susceptible to surging. (It is quite interesting that the rear ramp side gaps were not in the least bit critical, and if Concorde intake development had continued, the rear ramps were going to be deleted altogether). Other failure factors were control unit malfuntions, rapid sensor drift; all of these causing either ramp/spill door drift or runaway. Primary nozzle misbehaviour could also result in intake surges. Having said all that, the monitoring of the intake system was truly superb, and surface runaways, themselves quite rare, would usually be picked up by the control system monitors causing either a lane switch or if that did not work, a total 'red light' failure with the surfaces frozen. No surge was treated as 'just one of those things', and much midnight oil was burned and hair pulled out (so that's what happened to mine ) to try and find the cause of the surge.
My friend EXWOK perfectly answered the intake hydraulics allocations.
EXWOK was right on the ball here as usual, in fact above Mach 1.6 an interactive surge was more or less guaranteed. The cause of interactive surge had nothing to do with the wing leading edge position, but to the radially generated distortion field coming out of the FRONT of the surging intake, severely distorting the adjascent intakes airflow. It mattered not if the originating surge was an inboard or an outboard intake, the other guy would always go also, above Mach 1.6.
You might want to take a look at 'When Intakes Go Wrong Part 1:
http://www.pprune.org/tech-log/42690...-thrust-5.html
and Parts 2 & 3:
http://www.pprune.org/tech-log/42690...-thrust-5.html
Not to mention Part 3:


dixi188
I can never recall this particular event happening with BA , certainly not as a result of a ramp failure. Although in the near 28 years of operation we had quite a few SNN diversions, none that I can ever recall were as the result of a ramp structural failure. The two major SNN diversions that I can recall were G-BOAF in the early 80s when an LP1 blade failed and resulted in a totally wrecked engine (although a completely contained failure) and G-BOAA in 1991, with another wrecked engine due to running in rotating stall. (Both of these events were covered previously in our thread). ChristiaanJ has mentioned quite rightly the event with A/C 001 spitting a ramp out, and Air France had a ramp failure going into JFK. (Covered previously in our thread, due to certain 'human foul ups'). I am not sure, but I think that this one in JFK DID require a double engine change in JFK. (Usually from SNN a BA aircraft would be 3 engine ferried back to LHR).

ChristiaanJ
Nope, you are quite right, no more French or British development aircraft ever suffered a ramp linkage failure again. The 001 ramp failure was a salutary lesson to the design team, and the intake assembly became tougher than old boots after that, nomatter WHAT you threw at it.


Due to the lateness of the hour (and me being up at 4 ), that will have to do for now guys.

Best regards to all
Dude

Howie the engine that you saw WAS the one removed from 001. Flight International said at the time 'Only an Olympus could swallow an intake ramp at Mach 1.9 and still run at 85% N2'

Best regards
Dude

dixi188
This incident could well have been G-BOAD #2 engine then; this one swallowed an intake ramp brake assembly. Details of this incident itself can be found in the links that I posted regarding 'When Intakes Go Wrong'

Regards
Dude .

Nick Thomas
Jeepers Nick, I must have about a million, but I'd like to share a few here. (Some of them I have prattled on about before in this thread, so I apologise for any repetitions).I suppose my very FIRST Concorde image would have to be in Swindon in 1970, when I was this young RAF 'erk' at nearby RAF Lyneham; I heard this loud roar in the sky over what is now Debenhams, and looked up and saw for the very first time Concorde 002, along with her attendant Canberra chase plane.
My next memorable image was at Fairford in the summer 1974. (No longer a young RAF erk, but a still fairly young lad now working for BAC). I'd seen quite a few spectacular take-offs in my short time at BAC, but A/C 101 (G-AXDN) was being flown by a French DGAC pilot (I forget the gentleman's name I'm afraid) and did the most amazing of take-offs. It was the clearest of blue summer skies, and this guy rotated 101 and just climbed steeply into the Gloucestershire sky, and climbed and climbed until she was virtually out of view; truly memorable.
Another image that I will never forget is the view of Concorde taking off from JFK RW31L, viewed from the right side of the runway sat in a truck (I did this dozens of times and never tired of watching the spectacle). It always amazed me how ANY airliner could turn and climb that amazing fashion, and would try and keep her in view as she did an almost complete circuit around JFK. (But I found the view from the aircraft, when seated in the supernumerary seat just behind the captain even more amazing. You'd looked out of the rear L/H window and see nothing but the water of Jamaica Bay going by, very fast and VERY close).
Another GREAT image was in 1995; on a special test flight on-board G-BOAD out of LHR. I was sat on the flight deck with the three guys (just us four on the whole aeroplane) and we were positioned just aft and to the left of the BA189 Concorde service to IAD. We started the supersonic acceleration together, but as we peeled off south for our extensive test flight, the BA189 (can't remember for the life of me the registration) just seemed to streak ahead just like the Starship Enterprise, and was out of sight completely quite soon after that.
And I shall never forget the very sad view of the last ever Concorde take-off, watching from the side of Heathrow RW 27R in November 2003. OAF took off with all her usual grace, but symbolically just disappeared into the overcast, dark and gloomy sky. My own final personal image after 33 years of watching Concorde is that the aviation world, just like that November sky, is a far gloomier place without her.

Best regards
Dude

Christian, this is a wonderful book by the late Brian Calvert, in that although he goes into quite a few of the more intriguing Concorde technicalities, he does so in a manner that is easily understandable, even by me , and gives a wonderful insight into what it was really like to fly this amazing aeroplane. I had the pleasure of working with Brian on a 1994 BBC2 Concorde documentary, my brother had the shock of his life while on holiday in Mauritius the same year, when he picked up a copy of The Times only to see Brian and I 'posing' together in a publicity photo for the programme.
The other two Concorde books that I would personally recommend are 'New Shape in the Sky', by Ken Owen and 'Supersonic Secrets' by Rob and Edwin Lewis. These two books, one old and one quite new, are absolute Concorde classics in my very humble opinion.

Best Regards
Dude

Nick Thomas
It really was totally amazing Nick, both when viewed from the ground and ESPECIALLY from the 'jump seat'. (We are talking pre-9/11 here of course). The problem was, the likes of my friend EXWOK made it look far too easy at first sight, but when you looked at the event more closely you realised that it was really a combination of a superbly manoeuvrable aeroplane and some superb, highly co-ordinated and disciplined flying by the three guys up front. (After experiencing my very first '31L' in the early 90s, after the turns and throttling were complete I remember saying to the captain 'can we do that again Chris, CAN we? ).
It used to be quite interesting at JFK, comparing the take-offs of Concorde and the 'blunties', as EXWOK affectionately refers to the subsonics. You always asked yourself 'if Concorde can do that why can't the rest? But again, as EXWOK said, 'it's just not the same'.

Best Regards
Dude

CliveL
First of all a hearty welcome from myself also to the thread, speaking as a fellow old Filtonian/Fairfordian. (I'm sure I must have bumped into you during my years at BAC Clive).
It is thanks to the tremendous skill and dedication of 'designer chaps', such as yourself and ChristiaanJ, that Concorde became this breathtakingly amazing aeroplane that she was. I can't wait to read some more of your informative posts; you obviously have one hell of a story to tell, and can obviously teach us all (especially me) a thing or three.
It was thanks to this superb system for sealing off the engine bay (as well as actuating closed the nacelle ground running flap) when the ESDH (fire handle) was pulled, that generally limited the damage caused by the engine bay fire you mentioned on G-BOAF in 1980 to the affected engine only. (Save as you say, those small holes in the centre wall). Also worth mentioning is the fact that extinguisher pressure would also trip a 'fire flap', that would isolate the ram airflow into the air conditioning heat exchangers, that were mounted directly above the engines.. In the case of the aforementioned incident, this was just as well, as both heat exchangers were seriously damaged by the fire, and another potential source of oxygen was fortunately removed. Yet another truly brilliant piece of design.

Best Regards
Dude

ChristiaanJ
Not quite right I'm afraid here my friend. The superb Vulcan used self-contained electro-hydraulic PFCUs, similar in concept to the VC10. The pilot signalling from the fighter type joystick to the PFCUs however was still mechanical, no FBW here.

EXWOK
Oh Amen to that. Although quite complex in its concept, at least 'our' system was logical and intuitive, with full pilot control throughout.

Best Regards
Dude

PBL
As far as the Autothrottle side of things (you know, the throttles actually MOVING in response to autothrottle action, how novel ), that was designed by the Elliot part of the Anglo-French AFCS consortium. (This then became Marconi-Elliot, and then GEC-Marconi, and finally part of BAe Systems). I doubt very much if this is in anyway connected with Airbus at all. (I know,...Duh!!).
As far as the Concorde engine power control philosophy, well this was Rolls-Royce, through and through, with some BAe input, so again I think you can rule that out too.
Basically PBL, I would say that in answer to your question, we can say that they were definately not, thank goodness ... (Naughty boy, Dude ). Bearing in mind of course that the current Airbus philosophy can be traced back to the early A320s.... not a Roller in sight there.

Best Regards
Dude

CliveL
At BA the ZFW & ZFCG were sent to the aircraft from Load Control via NOCARS . Only joking folks, with no third VHF ACARS never happened, it was VHF verbal. On charters a despatcher would usually either fly with the aircraft or be positioned at the charter destination in order to make the load control calculations. My pilot buddies will confirm this I'm sure
(I seem to remember that in the early 90s we were looking to fit Concorde with ACARS, but when informally approached, Filton pleaded 'please, not another aerial position '.... we had only just got over the TCAS installation issues you see).



... Oh, he was Vietnamese eh? And not LOOPY??????
tee hee, We are certainly living and learning here thanks Clive, keep on posting .

Best Regards
Dude

Thanks EXWOK, as always I humbly stand corrected. We DID take one with us when we took OAG to BKK, and I do remember a few other occasions when a 'cap' got positioned. But this worn out brain does remember you guys doing L&B stuff when away.

Best Regards (And I hope you're not working over Christmas... I am )

Dude

ChristiaanJ
But this was the beauty of Concorde, there was so much in the way of automatic protections and enhancements 'built in' that one could quite quite reasonably take it all for granted. That was definately true for most of the AFCS computation. (It's all your fault ChristiaanJ for helping to design such a great system ).
And now we have CliveL joining this thread, one of the true 'fathers of Concorde', it can only become even more fascinating with his inputs here.
(BTW, this thread has now passed 100,000 viewings in just four short months ).

Best regards
Dude

MrVortex
Concorde had triple-axis auto stabilisation, where pilot demands were routed via an AUTOSTAB COMPUTER and summed with any stabilisation demands. There was automatc roll/yaw crossfeed, where for a given roll demand there was a coresponding amount of rudder applied, the amount of which was a function of Mach number. As far as 'dutch roll' etc the autostab system employed rate gyros in the same way as a conventional 'yaw damper' would operate in an inferior (oops, my bad.. I mean SLOWER) aircraft.
The AUTOSTAB operated full time, irrespective of AFCS mode. (Perhaps EXWOK, NW1 or one of the other boys will confirm that TURB mode was seldom EVER used in airline service. It was a (if I remember correctly) a Pitch/HDG hold autopilot mode with reduced gain).

Best regards
Dude