Posts about: "Rolls Royce" [Posts: 32 Pages: 2]

M2dude
23rd Aug 2010, 08:28
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Post: 77
Biggles78
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What is the Yellow Arc on the Mach metre that starts at about M1.12?
This is the minimum Mach number that can be flown with the existing CG. (which would be around 59%). Just as the CG indicator (not shown in this photo) gave minimum and maximum CG for a given Mach number, the Machmeter gave a reciprical indication also). You can also see that as the aircraft is not flying at Vmo any more, being at Mach 2 cruise, that the VSI pointer is now away from the orange and black Vmo bug. At our 'not so coffin corner', now that the aircraft is at maximun alllowable altitude, Vmo would naturaly coincide with Mmo; the orange and black Mmo bug being shown at Mach 2.04. This really superb photo taken by Bellerophon gives a graphic illustration of what the panels looked like at Mach 2. Note that the with the TCAS VSI Concorde retained it's original linear VSI also. (Miust have beeen the only aircraft flying with FOUR VSIs. (The originals had to be retained due to the fact that the autopilot Vert' Speed Mode error was derived from the indicator itself. As far as TCAS goes, R/As werer inhibited above FL300 (on acceleration this would coincide with the aircraft becoming supersonic, and the mfrs would not countenance the aircraft doing extreme manoeuvrs as a result of TCAS RAs at supersonic speeds).
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The center rear fuselage gear unit, what was that for? I have seen it deployed on many occasions but I can't for the life of me remember if it was during T/O or LDG however it didn't seem to be extended every time the aeroplane flew. Was this used during loading so she didn't accidently "rotate" at the ramp or to avoid a tailstrike during LDG? I can't imagine an over rotate during T/O.
The tail wheel was lowered for all 'normal' gear cycles (not stby lowering of free-fall). It was designed to protect the bottom the nacelles in the case of over-rotation, but in practical terms the thing was a waste of space (and weight) and a simple tail skid (used on the prototypes) would have sufficed. Any time that the tail wheel contacted the ground, it would ALWAYS collapse, damage the tailcone structure and in fact aforded no protection whatsoever. Fortunately these events were EXTREMELY few and far between. The biggest problem with the tail wheel was a major design flaw: On gear retraction the assembly would retract in sequence with the nose and main gear, and as it entered the opening in the tailcone, it would release over-centre locks that were holding the spring-loaded doors open. The doors would then firmly spring shut behind the gear assembly and finish the job. UNFORTUNATELY this was a very poor design; if for any reason one of the two doors had not gone over-centre on the previous gear lowering, it would be struck by the retracting tail wheel gear and cause structural damage to the local skin area, that would have to have a repair done. Unfortunately these events were not quite so rare, and several measures were tried to reduce the chance of this happening. Although not a safety issue, it was an issue that was a total pain. (As a matter of interest, G-BOAC had this happen on one of it's first test flights out of Fairford in 1975).
Nick Thomas
Quote:
As regards fuel burn: was there any difference between each indvidual airframe and if so was it significant enough to be considered when calculating the trip fuel? Also did different engines also have slightly different fuel consumption?
As ChristiaanJ said, the last two BA aircraft WERE lighter than the others, and would be preferred aircraft for certain charters. But that is not to say that any aircraft could not happily do ANY sector. We fortunately had no distorted airframes in the British fleet, so this was never an issue. There was very little spread, regarding fuel consumption between different engines; one of the best parts about the Olympus 593 was that it hade very little performance deterioration with time, it was an amazing piece of kit.
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Whilst on the subject of engines, I just wondered how many were required to keep the BA Concorde fleet flying? What sort of useful life could be expected from the engines?
Time on wing for the engines was a real variable. Each engine was built up of modules, each one of these had a seperate life. In the early days of operation, time on wing was quite poor, and MANY engines would be removed on an attrition basis. One of the early failure problem was the fuel vapourisers inside the combustion chamber were failing, taking bits of turbine with it!! A Rolls Royce modification that completely changed the design of the vapouriser not only solved the problem completely, but also increased the performance of the engine. As the engine matured in service time on wing greatly improved, and in service failures became a thing of the past. A 'trend analysis' was done after each protracted supersonic flight, where engine parameters were input into a propiatry RR computer program, that was able to detect step changes in the figures, and if this were the case, more boroscope inspections were carried out. The OLY time on wing was nothing compared to the big fan engines, but the conditions that it operated under bore no comparison. Not really sure about absolute figures on this one Nick, I'll ask one of my Rolls Royce friends and see if I can find a figure.

Last edited by M2dude; 19th Jan 2011 at 13:42 .
galaxy flyer
31st Aug 2010, 21:26
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Post: 171
The BR710 on the GLEX and G 550 also need to "rotor bow" on start within the same time limits. I fly the GLEX and the FADEC does it automatically, but I understand the G550 installation requires the pilots to recognize the requirement and motor for 30 seconds. Sub-idle vibration is quite discernible during an unbow start. Interesting that RR engines require this as I have flown GE and P&W, never heard of it.

GF
jodeliste
29th Oct 2010, 16:11
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Post: 626
Nitpicking

A detail I know but wasnt the Olympus really a Bristol engine? (cf Hooker "not much of an engineer" )I know RR bought the company but it wasnt their original design
rod
M2dude
29th Oct 2010, 16:25
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Post: 627
jodelistie
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On which there was a splendid rumour that what put the final nail in the great birds coffin was that our transatlantic allies realised that if hijacked there was nothing that could catch her !!
First of all Rod, welcome to our Concorde thread, and thank you very much for your kind words.
Now as far as the rumour goes, I'm afraid that it is nonsense, however the truth is an even more complex story of collusion, betrayal and intrigue. You may read that 'Concorde was retired by BA and Air France purely due to economic reasons', however that is not quite the case (and as far as THIS side of the English Puddle goes, is total poppycock!!). Now BA lost a huge amount of her regular traffic as a result of the 9/11 tragedy and also as a result of the 2003 Iraq war, but things were improving nicely. In her 27 years of operation, Concorde had survived countless dips in her traffic, only to return stronger as market conditions improved.
It is early 2003, and French Concorde traffic to the USA has almost vanished, down to single digit loads. This is due mainly to total French opposition the impending US/UK invasion of Iraq, and US businessmen using BA Concorde almost exclusively. (French business seems to be boycotting the US altogether, so their contribution to passenger loads virtually ceased). Due to the apalling loads, AF are losing absolutely MILLIONS of Euros, at a time when the carrier is trying to privatise itself ... but there is more:
In the same February, AF very nearly lost ANOTHER Concorde, yet again largely down to total incompetence and lack of adherence to established procedures. Aircraft F-BTSD was flying between CDG and JFK when there was a failure of the reheat delivery pipe that runs from the engine 1st stage fuel pump to the reheat shut-off valve. This failure, although not particularly serious, led to a chain of events that very nearly resulted in the loss of the aircraft, and all those onboard. (Air France engines were overhauled seperately to BA, who never experienced this particular failure). What was required in the case of this failure was a precautionary engine shut-down, closing off the fuel supply to the engine totally, and a descent/deceleration to subsonic speed, carefully monitoring fuel consumption all the time. Unfortunately the crew 'forgot' to shut down the fuel LP valve, and this resulted in the fuel continuing to gush out of the failed pipe at an alarming rate. (Oh, and also they forgot to monitor the fuel consumption). Only after the crew FINALLY noticed that they were still losing fuel did they remember to close the engine LP valve, but it was almost too late. The aircraft just managed to land in Halifax, with barely enough fuel left in the tanks to taxi!! So, herer we are, AF are horrified that they have come very close to yet another disaster, knowing full well that yet again human error was a major factor.
But there is more....
One week later another AF aircraft loses part of a rudder panel due to de-lamination of the honeycomb surface, not particularly serious in itself, but it put even more jitters up the trousers of AF. (Rudder failures had happened to BA aircraft many years previous to this, but BA had purchased brand new and improved rudders from Airbus UK in Filton, but Air France chose not too).
So it seems that the chairmen of both Air France and Airbus (who regards Concorde as a waste of its valuable resources) have a 'secret' meeting to plan what was effectively the murder of Concorde. There is no way that AF want BA to carry on flying Concorde while they have to cease operations, so the plan is for Airbus to make a huge hike in their product support costs; these costs would have to be borne by BA exclusively, which they both knew would not be possible. If these support costs were not met, there would be no manufacturers support, and without this there would be no type certificate, and without this, no more Concorde.
Their (AF & Airbus) hope was that BA would not challenge this move legally, and sadly for the world of aviation they did not. At a meeting, BA AND AIR FRANCE!!!! were told by Airbus about the hike in product support costs, and BA would also have to cease operations. BA were not even allowed to continue until March 2004 (the Barbados season was nearly fully booked already), and so would have to cease operations in October 2003.
But the British were far from blameless in all this; a now retired very senior British airline person had always obsessively HATED Concorde, so the French conspiracy was a very early Christmas present for him; he finally got what he had always wanted. The 'end of Concorde' anouncement by both airlines was made in April 2003; AF had got what their executives wanted and finished flying in May, reluctantly leaving BA to fly until late October. If you want a full (and extremely well informed) explanation of what happened in that whole debacle, the article by Don Pevsner is worth reading. It can be found at this website:
THE BETRAYAL OF CONCORDE
There is absolutely no doubt in my mind that without the truly disgusting events in France in early 2003, Concorde would still be proudly flying for BA. (And with modifications and enhancements would fly safely for many more years).
quote** "in the hands of true professionals, Concorde was the safest aircraft that ever flew. and in the hands of BA crews at least, she was always just that..*

Oh and yes you were correct, the Olympus (the world's first ever 2 spool engine) was originally a 'Bristol-Siddeley' design, before BS were absorbed into Rolls-Royce. Stanley Hookers book is in my view totally superb, a true classic.

Dude

Last edited by M2dude; 29th Oct 2010 at 16:52 . Reason: spelling (yet again) :-(
M2dude
18th Nov 2010, 12:25
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Post: 724
Mr Vortex
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- So once we select the Engine schedule to mode Hi or F/O the Prim nozzle will open wider causing the pressure at the Prim nozzle to drop and hence the higher flow of the exhaust through the LP turbine = Higher N1 RPM. Am I understand it correctly?
More or less you are correct yes, but remember that schedule selection was more or less automatic. ( E Flyover was armed prior to take-off, and E-MID during approach by the E/O, otherwise it was more or less a 'hands off' afair).
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According to your reply, the E schedule that will provide the most thrust is the Low mode since the prim nozzle area will be the smallest among all of the other mode which mean the highest pressure and temperature. Am I understand it correctly? And if so why do BA [as far as I know] told the FE to use Hi mode? Because the higher thrust can be obtain with higher N1?
Oooo no, we are way adrift here I'm afraid. I'm trying not to get too 'heavy' with this explanation, and I've enclosed below the Rolls-Royce E Shedule diagram to try and help clarify everything. (I've edited out the exact equation figures in deference to Rolls-Royce). Where N1/√θ and N2/√θ is quoted, the term ' θ ' related to T1 in degrees K/288 . (288 deg's K being 15 deg's C). The hotter things are the higher the spool speed scheduled is, and visa-versa for lower temperatures. Only at a T1 of 15 deg's. C (Standard day temperature) does N/√θ equate to N. (But remamber that T1 is TOTAL temperature, that varies with Mach Number).
The use of E LOW above 220KIAS was not only strictly inhibited by the automatics, if you over-rode the automatics and 'hard selected' E LOW , the aircraft would fall out of the sky when reheat was cancelled at Mach 1.7. This was because the low N1/√θ scheduled by E LOW would now invoke an N2/√θ limit (The E3 Limiter in the diagram) and claw off fuel flow by the tonne.
The most efficient schedule for supersonic cruise was E HI which again would be automatically selected.
E-MID was automatically selected during afterburning operation, to minimise the chance of an N1 overspeed on cancellation of reheat. E-MID could also be selected by the E/O for noise abatement approach.
E Flyover was as we discussed before used for take-off flyover noise abatement as well as subsonic cruise if desired. (If Mach 1 was exceeded with E Flyover still selected, a yellow NOZZLE light illuminated and E HI would be automatically selected.
I sincerely hope that this blurb is not clear as mud, feel free to ask away.
Quote:
- Also does the the Hi mode can deliver the higher N1 RPM, does that mean the Engine control unit must deliver the higher fuelflow rate in order to keep N2 run at the constant speed [higher N1 speed => higher pressure => more resistance
=> higher Fuelflow require to keep N2 run at constant speed]
Nope, that is the beauty of it all. Because of the part choking of the LP turbine section of the engine, the pressure changes due to Aj variation were felt exclusively by N1 and not N2. (Clever, these Rolls-Royce guys ).
Regards

Dude

Last edited by M2dude; 18th Nov 2010 at 15:04 . Reason: I goofed.. (another sign of age)
notfred
29th Nov 2010, 19:07
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Post: 813
Engines and touch-and-go

I found a reference (via Wikipedia) to 67 Olympus 593 built in total.
The Rolls-Royce SNECMA Olympus 593 Concorde Engine - the fascinating full story of the Olympus 593 Mk610 from concept to service

I remember seeing a picture a few years ago of a Vulcan doing a touch-and-go at an airshow and rearranging the tarmac with the. With the mentions that have been made of the little clearance between the nozzles and the ground in landing config, did Concorde ever come close to doing something similar? Was careful consideration taken of the runway surface before doing a touch-and-go at a display?
howiehowie93
1st Dec 2010, 14:04
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Post: 822
Well I have to say this is a brilliant thread.

I stumbled upon it by accident and been catching up on it when I had a spare moment and have found it completely riveting and it has whiled away many hours over the past month.

I\x92m ex-RAF and spent the last ten years working as an engine bloke on the T aeroplane & RB199. We were always told there were many parallels with Concorde & the Olympus 593 \x96 TBT/T7 Gauges, Optical Pyrometers, EPC Coils on-engine FCU\x92s, Vapour Core Pump for reheat fuel as well and the like. I attended the RR Manufactures course for two weeks at the Patchway Works and spent a day at the Concorde Museum seeing the similarities with the Electronic Control Units too though Lucas Aerospace made the MECU\x92s or GR1/4 (& DECU\x92s on the F3\x92s).

Also while on the course the distinguished RR Instructor Gent filled up in with various snippets of Engine History too such as the Vaporisers which were fitted to RB199 & the later models of Olympus 593 were originally Armstrong Sidderly designed for the Sapphire, also I learned the whole 15 Stage Sapphire Compressor was lifted completely and fitted to later Avon\x92s as it worked better.

I was at Leuchars in the early 80\x92s and the Open Golf peeps all arrived in one of these magnificent lady\x92s \x96 the visit was notable for several things; someone fired off an escape chute!!! \x96 What does this little handle do on the Main Oleo ??? whoosh ! and after the dusk take off the pilot beat the place up several times in full reheat !!!!

My last place of work before I was de-mobbed was at the RAF Marham Engine bay and I had the good fortune to meet an RR Technician called Phil (second name escapes me) but he was part of the team of RR Controls Engineers during the Hot & High Trials. He said they used to modify the three \x93Amps\x94 for each Engine control \x96 Lane1, Lane 2 & Reheat on the fly and the aircraft often flew with different schedules installed on all four engines \x96 I think the aircraft at Duxford has these still fitted in the racks (??M2Dude??) but that\x92s another Tonka thing too; three control lanes. Were all these Amps combined into one black box??

They are always Amps in RR Speak?? The Spey 202 had \x93Amps\x94 in its reheat system too.

I was lucky to find a job with the TVOC in 2001 until they ran out of money (as they do) and worked to have their flight worthy Olympus 20202\x92s tested at RR Ansty but left before that happened. In fact I don\x92t know if it did happen though it was a CAA requirement. While I was there we were working with Alan Rolfe & Mike Batchelor of the RR Historic Engine Department were offering support too. (593\x92s were their responsibility also !!! Historic !!!) but I think that was unofficial until there was an agreement about the costs.

After that I worked in industrial applications of Olympus (and Avon) and worked on many installed Olympus in power generation but based on the 200 Series \x96 I think the 300 was thought to be too fragile. But I did have a good look at Olympus 2008/003 Still in good working order in Jersey on the Channel Islands with it\x92s Bristol Sidderly Name plate on it. They didn't have Inlet Guide Vanes as the 300's had but just 6 Forward Bearing Supports, hollow with anti -Icing air blown though, controlled by a Garret Air Valve.

I never saw a DEBOW sort of function on the Industrials but there is a critical N1 speed which has to be avoided because the LP Turbine Disc can fail. The Trouble with that speed range is that it is right where the usefull power is produced!!! Was there any Normal Operating Range RPM's which had to be avoided on the 593 ?

Again thanks very much for all the fascinating information here\x92s to another 42 pages!! Sorry to have rambled on so much

Howie
M2dude
2nd Dec 2010, 11:33
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Post: 823
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
2nd Dec 2010, 15:04
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Post: 825
Thanks M2Dude.

Yes Hot Streak Reheat Ignition on the RB199. Only problem was the Injector was right underneath (or perhaps on top is more accurate! ) of the Reheat FCU and as it jutted out into the Combustor it was often blocking with carbon . so either - off with the RHFCU or disconnet the pipe and try the OM15/Landrover Speedo cable cleaning out trick. There was eventually a test set to tell you if it was still blocked (helpfull - NOT).

I'd left by this time but I was told RR came up with a way of back flushing combustor Pressure to clear it out with some success.

regards
HH93
M2dude
3rd Dec 2010, 12:19
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Post: 828
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
ChristiaanJ
3rd Dec 2010, 18:22
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Post: 831
Quote:
Originally Posted by M2dude View Post
The whole idea of adapting hotstreak injection came from our Rolls-Royce rep', who spent many years on RB199 development...
Can somebody explain to a "Volts and Amps and Ohms ancient" what "hotstreak injection" is/was (without getting scabrous)?

Quote:
....another other main problem was reheat 'coming in with a thump',
Many thanks for that story, M2dude, and no problem understanding it that one.

Quote:
The TSR-2 information makes amazing reading (what a truly magnificent aircraft) , and as Concorde's military cousin, discussion here is in my opinion most warranted.
Same here.
Quote:
.... purists might regard it as being 'off topic'
Purists be damned.
Concorde wasn't created 'ab nihilo', in a vacuum, as it were.
So, placing her squarely in the aviation world of the time should be part of the thread and the story.

In my own field (avionics) both TSR-2 and Concorde are almost "snapshots" of technology at a given time, a technology which was changing very rapidly.

I may go and rabbit on about that some more, one of these days, but describing what happened in the avioncs/electronics field is always more difficult than the purely mechanical, engine and structure progress.

CJ

PS A few years ago I had a chance to have a close look at some of the TSR-2 electronics in the East Fortune (Scotland) museum.
IIRC a lot of it was Ferranti.
It was an eye-opener as to how much technology had already changed from TSR-2 to Concorde.
M2dude
4th Dec 2010, 09:17
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Post: 832
Bellerophon
Quote:
Deciding that they would like to maintain this groundspeed, they went ALT HOLD and MACH HOLD at around FL530. They maintained their groundspeed, so the story goes, but the autothrottle then progressively reduced the N1, as the aircraft weight reduced, over the next couple of hours, into the prohibited range!Did you ever hear of any such event?
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
Quote:
Can somebody explain to a "Volts and Amps and Ohms ancient" what "hotstreak injection" is/was (without getting scabrous)?
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
howiehowie93
5th Dec 2010, 06:11
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Post: 835
More Olympus stuff

Greetings.

Service Bulletin 0420 Industrial Olympus Gas Generator \x96 LP Turbine Disc Cracking Safety Related Operational and inspection requirements.
to paraphrase:

Avoid steady operations in the range 5450 to 5850 RPM I believe that 100% is 8000RPM so that equates to 68 \x96 73%. It is ok the accelerate through that range apparently.


There seems to be a lot of history about Olympus LP Discs:
Test House 40 \x96 I think - at RR Ansty still has the deep groves in the brickwork where an engine broke up during test.
From Wikipedia:
\x93XA894 flew with five Olympus engines, the standard four plus an underbelly supersonic Olympus 320 fed from a bifurcated intake starting just aft of the wing leading edge and inboard of the main intakes, in a mock-up of the BAC TSR-2 installation. This aircraft was destroyed on a fire on the ground on 3 December 1962\x94

I read the LP Disc did a QANTAS A380 and decided to leave the engine:
An Aviation Heritage story

So there\x92s nothing new in the world really

regards
HH93


Last edited by howiehowie93; 5th Dec 2010 at 07:19 .
howiehowie93
5th Dec 2010, 12:44
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Post: 837
why was the Olympus so suitable

Quote:
what was it about the Olympus that made it so capable in so many guises and for so long?
IMHO I'd the simplicity of the design. I have worked on many flavours of Gas Turbines since I left the RAF in 2000, GE, RR, Rustons, (EGT, RGT the same really just a name change every few years and now Siemens) oh and Solar - who I work for now - better not forget them !!

All these engines from other manufacturers have complicated systems to make them efficient:
VIGV's (Variable Inlet Guide Vanes)
VSV's (Variable Stator Vanes)
Bleed Valves
Multi Fuel Metering Valves & other valves to keep emissions under control.

The Olympus - nowt ! Two Spools and a Fuel Valve thats your lot. nothing to go wrong and being an Aeroderivative all the ancillary equipment is either bolted on underneath or away from the engine outside the enclosure.

The only thing I had trouble with was the burner bolts shearing off, 1/4"BSF, if never touched in a good few years !

Was it all still BSF on the 593? That was a Bristols thing - true RR designs are UNC (well Avons are anyway)

oh ! I forgot about the Hot Shot; when I was ground running installed RB199's there was no jump in TBT/T7, you couldn't sense it fire either, the only feel was either the Reheat lighting off with a big roar or the engine going quiet as the Nozzle opened up until the MECU noticed it hadn't lit and closed it again sharpish.

Good eh
Regards
H wie

Last edited by howiehowie93; 5th Dec 2010 at 13:25 . Reason: Hot Shot paragraph added. Also SPELLING !! see me after school.
howiehowie93
12th Dec 2010, 05:45
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Post: 857
Quote:
PS I have no record of any of the British development aircraft ever having lost a ramp, notwithstanding the number of deliberate engine surges they went hrough. But then maybe I wasn't told....
There's a description and a picture of such an incident in the RR Heritage Book about Olympus. Happened in "Mach Ally" over the Irish Sea, even though the front face of the Compressor was wreaked it could still run up to 85% without surging. Can't remember which 85% though and the book is 4000 miles away from me at the moment.

Regards
H wie
Bellerophon
18th Dec 2010, 15:20
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Post: 876
JFK 31L, Kennedy 9 Departure, Canarsie transition, Concorde climb


Speedbird 2, cleared take-off 31L.

You call 3-2-1 Now , start your stopwatch, pre-set to countdown from 58 seconds, and slam the throttles fully forward till they hit the stops. Four RR Olympus engines start to spool up to full power and four reheats kick in, together producing 156,000 lbs of thrust, but at a total fuel flow of 27,000 US gallons per hour. A touch of left rudder initially to keep straight, as the #4 engine limiter is limiting the engine to 88% until 60 kts when it will release it to full power. The F/O calls Airspeed building, 100 kts, V 1 , and then, at 195 kts, Rotate . You smoothly rotate the aircraft, lift-off occurs at around 10\xb0 and 215 kts. You hear a call of V 2 but you keep rotating to 13.5\xb0 and then hold that attitude, letting the aircraft accelerate.

The F/O calls Positive Climb and you call for the Gear Up . On passing 20 feet radio height, and having checked the aircraft attitude, airspeed and rate of climb are all satisfactory, the F/O calls Turn and you slowly and smoothly roll on 25\xb0 left bank to commence the turn out over Jamaica bay. Some knowledgeable passengers will have requested window seats on the left side of the aircraft at check-in, and are now being rewarded with a very close look at the waters of Jamaica Bay going by very fast! As you accelerate through 240 kts, the F/O calls 240 and you pitch up to 19\xb0 to maintain 250 kts and keep the left turn going to pass East of CRI.

54 seconds from the start of the take off roll you hear the F/O counting down 3-2-1 Noise whereupon the F/E cancel the re-heats and simultaneously throttles back to noise abatement power, around 96% as you pitch the nose down to 12\xb0 to maintain 250 kts. It is less than a minute from start of roll and already 435 US gallons of fuel have been used.


Speedbird 2, contact departure, so long.

Turning through heading 235\xb0M, the F/E quickly re-applies full dry power as you pitch up to 17\xb0 to maintain 250 kts, but simultaneously reduce the left bank to 7.5\xb0, in order to increase both the radius of turn (to stay on the optimum noise abatement track) and the rate of climb (less bank, higher RoC).

On climbing through 2,500 ft you increase the bank angle back to 25\xb0 left bank and as you approach the 253\xb0 radial JFK, you hear 3-2-1 Noise from the F/O for the second time. The F/E actions the second noise-abatement power cut back, you pitch down to 12\xb0 and, if not in cloud, sneak a quick peek out of your left hand window, looking for the car park by the Marine Parkway bridge, as you would ideally like to pass right over the car park, if possible, as we tip-toe quietly across the Rockaway Beaches, in order to minimise the noise impact on the residents.

Keep the left turn going and intercept the 176\xb0 radial outbound from CRI, and at 5 miles DME from CRI, call for the F/E to slowly re-apply full climb power as you pitch up to maintain 250 kts. We are still in US territorial airspace, below 10,000 ft, and subject to statutory speed control.


Speedbird 2, present position direct to SHIPP, climb FL230, no speed control.

The F/O selects direct SHIPP in the INS and tells you that she has selected that information into your Flight Director. Having checked that the gear lever is at neutral, you call for the Nose Up , and then the Visor Up . Flight deck noise levels drop dramatically as the Visor locks up. Now more than 12 miles away from the coast, we are clear of US speed control requirements so lower the attitude to 9\xb0, accelerate to V MO , currently 400 kts, and ask for the After Take Off Checks.


Speedbird 2, present position direct to LINND, climb in the block FL550-600, accelerate Mach 2.0

Call for the Climb Checklist at Mach 0.7, which will trigger the F/E to start pumping fuel rearwards to move the CG aft, then when he's done that, straight into the Transonic Checklist . Maintain 400 kts IAS, and around 24,500 ft, at M0.93, ask for the re-heats back on, in pairs, and raise the nose by 3\xb0 to maintain 400 kts as they kick in.

Precise, smooth flying is required through the high drag transonic region, as the mach meter creeps up towards Mach 1. A sudden flicker on the VSI and Altimeter confirms that the shock wave has just passed over the static ports, and the aircraft is now supersonic. A quick glance at the elapsed time indicator shows that you\x92ve been hand flying for just over 9 minutes since the start of the take off roll.

Another fun start to a day in the office, and to think we got paid for doing it!


Best Regards

Bellerophon
M2dude
21st Dec 2010, 11:13
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Post: 911
PBL
Quote:
And how do we know they weren't designed by the very same people?
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

Last edited by M2dude; 21st Dec 2010 at 11:36 . Reason: My crap spelling
CliveL
27th Dec 2010, 12:13
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Post: 1025
Quote:
Originally Posted by M2Dude
Unfortunately, this lot have a habit of talking with forked tongue as far as Concorde goes; you can not in any way be sure about this, and we should really stop believing everything that this lot in Toulouse tell us . (Recent history here has taught us this all too well, and nothing would please scarebus more than there to be no reminders of Concorde at all on the airfield at Filton). More to the point, there is absolutely no certainty that the Cribb's Causeway site will ever be built anyway, you just can NOT say that the airframe will not ne broken up for road transportation, because if she does go to another museum in the absence of the Cribb's Causeway site being built, that will DEFINATELY happen. But at least we now have another 'written off' British Concorde; I guess this fact obviously pleases some people


I've pulled this quotation out at random from what I have found a rather disappointing sequence of postings. I could write reams about this (and like everyone in this thread I would write as a Concordophile), but I won't - or at least I will try not to. In general I'm with Christian on this, and for the record I think a few 'counterfactuals' should be recorded. I am not trying to reopen a sterile debate - as CJ has said irrevocable decisions have been made and the subject is done and dusted. However, let us remember that:

G-BOAF was, and is the property of BA; BAe and now AI are merely caretakers.
AI's statement cross-posted from the Heritage website strikes me as a very reasonable statement; we found that your roof is leaking, if you don't get it fixed it is going to get worse rather rapidly; if you (BA) agree and will pay us to do it we will take it indoors and fix it. I don't see any sinister intent here, and given the weather we have had in the UK over the past weeks it must be regarded as a happy, if fortuitous decision!
Those who know Filton will also know that there is nowhere that Alpha Fox could be stored under cover except in the hangar where she was first assembled. They will also know that this hangar is buried in the centre of the factory and nobody, in a post 9/11 world, is going to give more or less unrestricted public access to somewhere containing a lot of valuable real estate! So when BA took the decision to locate AF at Filton it must have been in the knowledge that she would live in British weather until some form of shelter could be organised.
That it has taken so long to (fail to) organise such shelter is regrettable, but the blame can hardly be uniquely allocated to AI. BA own the aircraft, BAe/AI had a 40% share in building the airframe, RR a 60% share in building the powerplant. IMHO they should all have chipped in to construct some sort of shelter - it was never on the cards that local enthusiasts could have raised enough in a short time.
Although 'Dude' says that all the UK airframes were left out in the weather, this is not exactly true is it? 002 at Yeovilton (certainly) and 101 at Duxford (I think) are under cover and receive lots of TLC. It is at least arguable that these early airframes have more historical significance than Alpha Fox.

So far as AI's decision to hand back the C of A is concerned, they would have already recognised from the post-Gonesse activity that most people with sufficient expertise on the Concorde design were retired (or worse!) They have enough people to keep a subsonic aircraft going, but Concorde would, I think, require additional experience. AI management would certainly have consulted AI Engineering about this, and I have to say that the then Head of Engineering was someone I know well. He, like me, worked on Concorde in the early days and he is definitely not antiConcorde. I for one would respect his decision.

So far as the decision to stop services goes, we all knew they would be cut off sometime.the only question was when. When we were designing the aircraft the general feeling was that she would stay in service for about 30 years, but we also feared that it would only need one fatal accident to bring the whole lot crashing down. [Incidentally, it was that latter philosophy that made us (we hoped) ultracareful with airworthiness issues] In the event it was 28 years and one accident.
Even before Gonesse AF were losing money on their Concorde services. One might have thought that they would stop right away, but I suspect that a combination of Gallc pride and politics ensured that they would carry on.
But eventually there came a point where, on an airline losing money and in a recession, an unsentimantal and yes, generally unsympathetic, management would have to say enough is enough.
What else would you have them do? Continue to fly loss making services so that their rival BA could go on with their profitable? operations? One would have to say 'Get real!'
Once AF had decided to stop, what do you expect of AI? They are a company with a duty to make profit for their shareholders. OK, they had a duty, also to support in service aircraft, but that duty does not extend to doing that at a loss. With AF out of it therefore AI had no alternative but to ask BA to shoulder the full bill. I have no doubt that when BA declined to do this AI breathed a huge sigh of relief, but at the end of the day the decision to stop all Concorde services was above all an AIRLINE decision.

Sorry to go rabbiting on, but it is a subject that arouses strong emotions!

CliveL
howiehowie93
17th Jan 2011, 14:20
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Post: 1114
Brit312 wrote:
Quote:
Discharge valves

The same logic went for the engine starting ignitors which were used Lh or Rh per sector. This logic caused more problems with starting than any other although a way was found to over come this problem
Really alternate side Ignitors? All RR aero engines I have worked on always sparked up both sides every time, well the Avon, Spey 202, RB199 & the Oly 20202 (Vulcan) and industrial Oly did. Would this have made a difficulty with starting logic??

Was there LH & RH Ignition selector switch maybe?

I hope I haven't missed further comment on this since page 50 but just back off my Hols and raced through to the end.

Also on a tangent a bit; the roll out picture further on was that a Nimrod's tail in the corner of the Hanger??

regards
Howie
Brit312
17th Jan 2011, 18:40
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Post: 1117
Quote:
For that reason, I believe, flight in mechanical signalling was removed from transonic flight on airtests and altogether from Base Training. The simulator was the only sensible way of trying to fly like that...
During the early years there was some doubt from the CAA that the aircraft could be handled in Mech signalling in the transonic region. Lots of meetings were held, and finally on a test flight the gentleman was invited again and one of the original training Captains flew the aircraft perfectly through the transonic area whilst descending in Mech Signalling. With that said it was a delicate area and control inputs had to be gentle and small so I understand


Quote:
Was there LH & RH Ignition selector switch maybe?

Yes there was an Ignitor selector labelled LH--Both--RH, however the engines would be started using only one ignitor. This caused a few small but annoying delays as if the selected ignitor failed the start would have to be stopped the starter given a cooling period and then a further engine start using the other ignitor would be attempted, however it did give a running check that both ignitors were working.

This was not very popular with the crews and the ground engineers were persuaded to test the ignitors before presenting the aircraft for service. However due to the engine starting Fuel Pump switching, this resulted with a small fire in the hanger, and so the crews were back to starting on Lh or RH ignitors.

If I remember correctly the RR Conways on the VC-10 also had 2 ignitors per engine with a LH--Both-RH selector.

Quote:
flying control pre-flight check! Learning it was a conversion course rite othat f
At one time there was a suggestion that BA adopt the Air France technique where the F/E did this check on the ground pumps prior to engine start, which did not go down very well with the F/E. It was fortunate that some one came up with the suggestion that this would wear the ground pumps out , and so this check stayed as apilot check after the engined were running [Thank God]

If you remember, if something went wrong with the Flying control check the F/E was always busy. This gave him a chance to think up a suitable answer or even better the pilots did the check again and it now worked.

Quote:
But the 'trainers' often used to come seek me out in the hangar and (over coffee, not beer I'm afraid) confer about various system quirks and nasties to use on you guys during the tech' refreshers
No dude we never came to see you boys for the "Pilots Tech Refresher" as we always had to keep those lectures very simple as otherwise the pilots would go to sleep.

Now I have to admit coming across the hanger to consult with you boys when preparing for a new sequence of F/E "Tech Knowledge Checks". Not that we did not understand it, you understand, but mainly to make sure that we were correct before some clever line F/E informed you of your error. Very embarrising that, and I should know