Concorde question

[M2dude]

Landroger

Which brings me to my questionette - given that Bristol-Siddley created the original design when jet travel was still quite novel, what was it about the Olympus that made it so capable in so many guises and for so long? Not only Concorde of course, but TSR2, warships and fixed electrical generators.

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

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.

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.

Was it all still BSF on the 593?

No mate, generally BI-HEX AF.

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.

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

How much would it cost, do you think, that IF EADS really wanted to, using a combination of all the knowhow gained through L'Oiseau Blanc and their current lineup could they produce a 'Concorde NG'? Most importantly, would there be a market for such a beast (at the right price)?

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

Ok, so my question is - BA had to use an airframe as a test for the modifications. However, the choice of airframe seemed a strange one to me, BOAF - which I previously thought to be one of the youngest and best airframe they had (m2dude you explained that BOAF and BOAG weighed less than the previous models). So, why would BA use one of their best airframes, rather than use perhaps the most worn out of their fleet?

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

I'm wonder that did Concorde has a neutal of stable stability? Did the elevon work out the same job to produce the stability like the elevator and stabilizer?

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.

Also, I have read your post and wonder why when the temp fall below ISA-7, the AICU order the N1 to decrese?

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/Öq) 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.

And the final question. In the early concorde, does the pilot has ability to select the amount of afterburn thrust by rotate the area knob is that right? and why the airline remove it?

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

[howiehowie93]

Mr M2Dude sir !!,

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.

Not quite right here I'm afraid. There are some designs which are coupled to the HP Spool - look up GE LM6000 for that but the majority of installations use the jet efflux to drive a separate (in a mechanical sense) Power Turbine which can be then either coupled to a gearbox or directly coupled to the load and run at a set speed as in power generation - i.e. 3000 or 3600 RPM for the frequency depending on which country. All the controls I've worked on govern the speed of this Power Turbine and the Gas Turbine, often called Gas Producer or Gas Generator, ramps up or down as required. Just being monitored to ensure it is operated within it's limits.

All Olympus installations are like this; ships prime movers, pumps, gas compressors, power generation all the same.

regards
Howie

[M2dude]

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

[kblackburn]

What a marvelous thread!

I have hitherto never really been 'hooked' on Concorde but am discovering some amazing stuff here, and am being 'converted' so to speak (still on Page 8, working my way through).

The input from our 4+ experts is both eloquent and highly informative You can read all you like about this aircraft, but 'hearing' detail first hand from designers, pilots and F/Es is wonderful.

Great stuff....

Keith

[M2dude]

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

[kblackburn]

Many thanks M2dude....that's great!

It was only when I went forward to make my last post that I realised there are 43 pages to the thread will make good bedtime reading

I will wait until I have read the complete thread before asking any questions of you guys...in case they have been asked before.

Cheers and all the best

Keith

[kblackburn]

Okay....couldn't wait until I had completed the thread review before posting a question (on Page 9 now ). One 'easy one':

I'm curious as to how difficult getting the C type rating was. Presumably only senior BA / AF people could apply but there must have been a huge learning curve involved, even for these experienced foiks.

Cheers - Keith

[ChristiaanJ]

Keith,
Welcome!
Your question has been answered in detail, but a bit beyond page 9.. read on and enjoy.

CJ

[kblackburn]

Thank you ChristiaanJ...

Dang! I knew I should have waited

I will read on and find the answer to my question in due course. Patience is a virtue so they say

Thanks again and very best wishes

Keith

[howiehowie93]

Not surprisingly there are other threads on here about Concorde, found this stunning picture on page 4 post #76:

http://www.pprune.org/aviation-histo...ircraft-4.html


Hwie

[galaxy flyer]

What was the ICAO code for the Concorde? What was on the license?

GF

[EXWOK]

Hi Galaxy Flyer -

When I first got the beast on my licence it was recorded as 'Concorde Series 102 & variant'.

(Translates as British-built series plus s/no. 214, aka G-BOAG)

These days it appears as just 'Concorde'. (I'm surprised it still appears at all since the type isn't current on the register).

It's a while since I filed a flt plan for a Concorde sector, but recall that it was entered as 'CONC'.

ATB

[EXWOK]

Pedalz -

I'm not the best person to reply to your ramp query - he'll be along later! - and it's been largely answered already, but the bare bones are this;

Ramp 1&2 Green system, back up of yellow, 3&4 Blue, backup yellow.

Any continuous surge at supersonic speed would affect the adjacent engine, hence the requirement to close all 4 throttles.

Cheers,

EXWOK

[dixi188]

A certain CFI (I think) at BA flying club, High Wycombe, who was also F/O on concorde, showed me some photographs of an engine that had eaten a piece of intake ramp.
I think he said that the adjacent engine had surged and a piece of ramp went out the front and down the other engine. This resulted in a double engine failure mid atlantic. They landed in Shannon with very little fuel left.

A double engine change ensued.

Question, how fast was the ramp going if the A/C was at Mach 2?

[ChristiaanJ]

Originally Posted by dixi188

A certain CFI (I think) at BA flying club, High Wycombe, who was also F/O on concorde, showed me some photographs of an engine that had eaten a piece of intake ramp.
I think he said that the adjacent engine had surged and a piece of ramp went out the front and down the other engine. This resulted in a double engine failure mid atlantic. They landed in Shannon with very little fuel left.

Maybe M2dude remembers the occasion?

First time that happened was on prototype 001 in the very early days, when an engine "spit out" the entire ramp (there's a photo in Trubshaw's book).
The ramps and actuators were 'beefed up' considerably afterwards... I didn't know an in-service aircraft had suffered a similar mishap.

Question, how fast was the ramp going if the A/C was at Mach 2?

Good question.... not being an "engine man" I've always been amazed how a nice steady Mach 2 flow, slowed down to Mach 0.5 at the engine inlet, is capable of totally choking off and even reversing itself in less than a second.... no wonder it's usually accompanied by a big bang!

CJ

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....

[M2dude]

Them darn intakes

Hi Guys, quite a few little points here, so here's my angle(s):
Pedalz

were the intake ramps in front of the engines ever known for problems? Especially during supersonic cruise where the airflow through the compressors and position of the ramps was determined by an exacting science which could turn into quite a situation if disturbed. Which hydraulic system actuated these ramps?

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.

Due to the shape of the leading edge and positioning of the intakes themselves, could it be possible that disturbed airflow from a problem ramp or donk could also effect it's outboard neighbour (if I'm right in presuming that only the inboard engine surging etc. could effect the outboard and not vice versa)?[/

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

A certain CFI (I think) at BA flying club, High Wycombe, who was also F/O on concorde, showed me some photographs of an engine that had eaten a piece of intake ramp. I think he said that the adjacent engine had surged and a piece of ramp went out the front and down the other engine. This resulted in a double engine failure mid atlantic. They landed in Shannon with very little fuel left.

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

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....

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

[howiehowie93]

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
Hwie

[jodeliste]

Stan Hooker

This is for Cristiaan ( and maybe others)

Ive tracked down my old VHS tape of the interview with Stanley Hooker which you said you would like to see, if you PM me your address I will send you a dvd copy
cheers
rod

[M2dude]

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]

M2dude,

The event I was shown the pictures of was probably about 1995 or 96 I think.

The engine LP compressor was very badly chewed by something.