13th Aug 2010, 09:45
permalink Post: 2
Hi Stilton, that is a question that we all used to ask ourselves; not having an APU was a major pain in the butt for the fleet, particularly at charter destinations, where air start trucks, GPU's and air conditioning trucks would all have to be pre-arranged.
One problem with 'Conc' was always one of weight, (for every extra pound you carried, another pound of fuel was required) so any APU installation would have to have been light, and worth the extra weight. But the main problem was one of 'where to put the darned thing. The only suitable space available for an APU was in the tailcone, aft of the tail wheel. Now a ready supply of fuel would have been available either from the aft trim tank, #11, or from one of the two trim galleries. (For stability reasons, tank 11 was invariably left empty during ground transits). The real crunch however, was how to arrange pneumatic services from an APU: Tank 11 was directly forward of the tailcone, so this would have meant either ducting the pneumatics THROUGH the fuel tank (not a particularly good idea
) or externally around the fuselage, which would have been 'draggy' to say the least.
You could still have had an APU powering hydraulics, and in essence electrics too (the emergency generator was powered from the Green System), but without pneumatics for engine starting and air conditioning, it would really have been a waste of weight. Still, it really is a shame that there was no APU.
Historically, there were 'sort of' aux power units fitted to development aircraft: The prototypes had two GTS's (Gas Turbine Starters), one in each nacelle pair, that could start the engines without an air start truck, but these never saw the light of day in later aircraft. The most unusual unit of all was the MEPU (Monogol Emergency Power Unit), located in the tail cone. This was manufactured by Sundstrand, and was fitted to all of the development aircraft. (A derivation of a unit fitted to the X-15!!). The idea was that if you had a four-engined flameout at Mach 2, this thing would fire up, power Green and Yellow hydraulics (plus the emergency generator, again from the Green system), and give you power and control down to a safe relight altitude. The MEPU was powered by Hydrazine rocket fuel (unbelievably unstable) and I seem to remember that the thing would run for about 8 minutes. There was no way that this monstrosity would ever be acceptable on a commercial aircraft, and so a conventional RAT was developed by Dowty for the production aircraft. (Also, the windmilling engines would give you full electrics down to Mach 1.1, and Hydraulics down to about Mach 0.7, so the thing had little practical use when supersonic anyway).
I hope this extended blurb helps answer your query Stilton.
One problem with 'Conc' was always one of weight, (for every extra pound you carried, another pound of fuel was required) so any APU installation would have to have been light, and worth the extra weight. But the main problem was one of 'where to put the darned thing. The only suitable space available for an APU was in the tailcone, aft of the tail wheel. Now a ready supply of fuel would have been available either from the aft trim tank, #11, or from one of the two trim galleries. (For stability reasons, tank 11 was invariably left empty during ground transits). The real crunch however, was how to arrange pneumatic services from an APU: Tank 11 was directly forward of the tailcone, so this would have meant either ducting the pneumatics THROUGH the fuel tank (not a particularly good idea
) or externally around the fuselage, which would have been 'draggy' to say the least.
You could still have had an APU powering hydraulics, and in essence electrics too (the emergency generator was powered from the Green System), but without pneumatics for engine starting and air conditioning, it would really have been a waste of weight. Still, it really is a shame that there was no APU.
Historically, there were 'sort of' aux power units fitted to development aircraft: The prototypes had two GTS's (Gas Turbine Starters), one in each nacelle pair, that could start the engines without an air start truck, but these never saw the light of day in later aircraft. The most unusual unit of all was the MEPU (Monogol Emergency Power Unit), located in the tail cone. This was manufactured by Sundstrand, and was fitted to all of the development aircraft. (A derivation of a unit fitted to the X-15!!). The idea was that if you had a four-engined flameout at Mach 2, this thing would fire up, power Green and Yellow hydraulics (plus the emergency generator, again from the Green system), and give you power and control down to a safe relight altitude. The MEPU was powered by Hydrazine rocket fuel (unbelievably unstable) and I seem to remember that the thing would run for about 8 minutes. There was no way that this monstrosity would ever be acceptable on a commercial aircraft, and so a conventional RAT was developed by Dowty for the production aircraft. (Also, the windmilling engines would give you full electrics down to Mach 1.1, and Hydraulics down to about Mach 0.7, so the thing had little practical use when supersonic anyway).
I hope this extended blurb helps answer your query Stilton.
13th Aug 2010, 16:07
permalink Post: 3
Yes,
M2dude
, but how long could you remain above M1.1 with a four-engine flameout while drifting down? I presume you would driftdown above M0.7. BTW, the RAT on the F-16 is hydrazine powered as was the ME 162 rocket interceptor.
13th Aug 2010, 18:53
permalink Post: 4
Point taken GF, but it was discovered during development flying that that the Olympus 593 could be relit, given sufficient IAS, at almost any altitude within the normal flight envelope. The variable inlet would even be automatically scheduled, as a funcion of N1, in order to improve relight performance at lower Mach numbers. I certainly agree that you would decelerate and lose altitude fairly quickly under these conditions, however a multiple flame out was never experienced during the entire 34 years of Concorde flight testing and airline operation. There was, as a matter of interest an un-commanded deployment of a Concorde RAT AT MACH 2!! (The first indications of the event were when the cabin crew complained about 'a loud propeller sound under the rear cabin floor'. A quick scan of the F/E's panel revealed the truth of the matter). The aircraft landed at JFK without incident, and the RAT itself, apart from a very small leak on one of the hydraulic pumps, was more or less un-phased by the event. Although it sounds horrific, a prop rotating in a Mach 2 airstream, the IAS it 'felt' would be no more than 530 KTS at any time. The RAT was of course replaced before the aircraft flew back to LHR.
Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. Or do you mean the the F16 has an emergency power unit? Either way, it's fascinating stuff.
Yes, I do remember that the Germans used Hydrazine as a fuel during WW2: The father of one of our Concorde pilots was on an air raid to destroy one o the production plants there, this aviation business is such a small world.
Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. Or do you mean the the F16 has an emergency power unit? Either way, it's fascinating stuff.
Yes, I do remember that the Germans used Hydrazine as a fuel during WW2: The father of one of our Concorde pilots was on an air raid to destroy one o the production plants there, this aviation business is such a small world.
15th Aug 2010, 15:22
permalink Post: 9
Quote:
| Not quite sure about your reference to the RAT on an F16 being Hydrazine powered; a Ram Air Turbine is just that, using the freely rotatting propellor to power hydraulics, electrics or both. |
18th Aug 2010, 12:27
permalink Post: 18
ChristiaanJ
Thanks for the MEPU link, that really brings back memories (or was that nightmares
). I remember at Fairford, a small drop of Hydrazine leaked onto the hangar floor; the next thing you heard was a really loud crack, and a after the smoke cleared, there was a sizable hole in the floor.
I'd still really like to know what the 'thoughts' on this APU issue actually were. Although as you rightly point out tank 11 already had a fair amount of 'plumbing' running through it, we are talking here about a duct with sufficient size that can provide enough mass flow to turn over an Olympus engine to at least between 10 and 20% N2. You are looking at an least 10" diameter duct, not including the copious amounts of thermal insulation surrounding it, as well as an extremely sensitive overtemperature protection system. (This tank is going to be near empty, filled with fuel vapour). I'm not really convinced that this idea would even be considered by the CAA/DGAC/FAA etc. for safety reasons alone.
Still, it's food for thought though
Thanks for the MEPU link, that really brings back memories (or was that nightmares
). I remember at Fairford, a small drop of Hydrazine leaked onto the hangar floor; the next thing you heard was a really loud crack, and a after the smoke cleared, there was a sizable hole in the floor.
I'd still really like to know what the 'thoughts' on this APU issue actually were. Although as you rightly point out tank 11 already had a fair amount of 'plumbing' running through it, we are talking here about a duct with sufficient size that can provide enough mass flow to turn over an Olympus engine to at least between 10 and 20% N2. You are looking at an least 10" diameter duct, not including the copious amounts of thermal insulation surrounding it, as well as an extremely sensitive overtemperature protection system. (This tank is going to be near empty, filled with fuel vapour). I'm not really convinced that this idea would even be considered by the CAA/DGAC/FAA etc. for safety reasons alone.
Still, it's food for thought though
15th Sep 2010, 17:39
permalink Post: 367
The blue area at the front is the MEPU firewall. My main memories of the MEPU on Concorde (Apart from the fact that it was always breaking down)was the awful STINK of the Hydrazine insode the tailcone. (Made your eyes water). Good photo though.
Dude
Dude
16th Sep 2010, 08:22
permalink Post: 369
I don't think you'll be finding hydrazine on a pax-carrying aircraft anytime soon! And it wasn't an APU as such, but a source of power for non-normals potentially found in the flight test programme. M2D and ChristiaanJwill know far more.
The charter flights were different insofar as they often went to non-BA stations, so there was a bit more donkeywork to be done to get all the paperwork organised, but nothing a regular charter pilot won't be used to. Generally one would get a fuel plan/flight plan filed from Ops at LHR, but apart from LHR/JFK/BGI/IAD (and presumably MIA/BAH/SIN in earlier days) we produced our own loadsheet. I only once had to produce a fuel plan/route plan from scratch and that was at Sondrestrom (as it was) with a dodgy fax line. You'd have to file a flight plan occasionally.
We carried a ' PR ' on most of them - a line pilot or FE - to carry out a running PA and do general liaison. They were volunteered to do the loadsheet.
The atmosphere on board was very different - these were pleasure flights and so were the opposite of the JFK business run. Landlady may be able to elaborate on this.
The round-the-worlds were just a big charter in this respect. As you note we carried a 'flying spanner', since Concorde-qualified LAEs are hard to come by downroute. It looked like a great job on paper, but they were often at the airport for many hours before or after the sectors carrying out routine maintenance or dealing with snags.
I enjoyed the charters a lot - everyone was geared up for a good time and in general the flight had something different for us, too: Whether a lightweight departure on a 'round-the-bay', squeezing into a short runway (e.g. Bournemouth), visiting SFJ or Rovaniemi, or setting off around the world, predominantly to non-BA destinations. My favourites, though, were the RTBs out of Filton - EVERYONE was either connected to Conc development or manufacture, or was related to someone who was. Fantastic atmosphere. Shame the runway wasn't a bit longer........
The charter flights were different insofar as they often went to non-BA stations, so there was a bit more donkeywork to be done to get all the paperwork organised, but nothing a regular charter pilot won't be used to. Generally one would get a fuel plan/flight plan filed from Ops at LHR, but apart from LHR/JFK/BGI/IAD (and presumably MIA/BAH/SIN in earlier days) we produced our own loadsheet. I only once had to produce a fuel plan/route plan from scratch and that was at Sondrestrom (as it was) with a dodgy fax line. You'd have to file a flight plan occasionally.
We carried a ' PR ' on most of them - a line pilot or FE - to carry out a running PA and do general liaison. They were volunteered to do the loadsheet.
The atmosphere on board was very different - these were pleasure flights and so were the opposite of the JFK business run. Landlady may be able to elaborate on this.
The round-the-worlds were just a big charter in this respect. As you note we carried a 'flying spanner', since Concorde-qualified LAEs are hard to come by downroute. It looked like a great job on paper, but they were often at the airport for many hours before or after the sectors carrying out routine maintenance or dealing with snags.
I enjoyed the charters a lot - everyone was geared up for a good time and in general the flight had something different for us, too: Whether a lightweight departure on a 'round-the-bay', squeezing into a short runway (e.g. Bournemouth), visiting SFJ or Rovaniemi, or setting off around the world, predominantly to non-BA destinations. My favourites, though, were the RTBs out of Filton - EVERYONE was either connected to Conc development or manufacture, or was related to someone who was. Fantastic atmosphere. Shame the runway wasn't a bit longer........
16th Sep 2010, 08:35
permalink Post: 370
BlueConcorde
As far as the MEPU went, yes there was just mainly empty space inside the tailcone, Aside from the tail wheel assembly there was just the power supply for the tail beacon as well as the fuel vent and jettison pipes. (On the forward bulkhead there were pumps and valves for tank 11). Having this great empty void did create problems in the early days of airline operation; there were some internal structural failures inside the tailcone (a low stressed area, so it was never serious). These failures were quickly attributed to acoustic fatigue inside the tailcone, due to resonance with engine and aerodynamic noise. This never occurred during any of the development flying; the prototypes and aircraft 1010 had a far smaller tailcone anyway, and aircraft 102, 201 and 202 had the bulk of the MEPU assembly complete with Hydrazine tank to fill up most of the void. The fix to the cracking problems was both very simple and quick to implement, and it never became a big deal. The MEPU, as has been mentioned a few times previous, was both useless and unsafe as far as a commercial aircraft goes; being replaced by a ram air turbine.
It's funny, but this is how this wonderful thread started over one month ago by stilton , I for one am so glad that it has both progressed and diversified the way that it has.
As far as charters go I'll leave it up to EXWOK or one of the other guys to answer, as far as flight planning goes. Thanks for your comments BlueConcorde, they always took a ground engineer on RTW charters, and although I never had the pleasure of directly participating in one (although I was on the end of a phone several times when problems occurred en-route)I WAS due to go in 2000, but tragic events in Paris caused that charter to be cancelled. I was however lucky enough to participate in various other charters, my most memorable one was in October 1991, when the World Bank chartered Concorde to Bangkok. The most amazing thing about RTW charters (or earth orbiters, as I would call them) was that the aircraft often returned to London with only a very small handfull of minor defects. The thing about Concorde was the more that she flew, the happier she was, and less likely to catch a cold.
PS. oops, EXWOK is already 'there'
Dude
As far as the MEPU went, yes there was just mainly empty space inside the tailcone, Aside from the tail wheel assembly there was just the power supply for the tail beacon as well as the fuel vent and jettison pipes. (On the forward bulkhead there were pumps and valves for tank 11). Having this great empty void did create problems in the early days of airline operation; there were some internal structural failures inside the tailcone (a low stressed area, so it was never serious). These failures were quickly attributed to acoustic fatigue inside the tailcone, due to resonance with engine and aerodynamic noise. This never occurred during any of the development flying; the prototypes and aircraft 1010 had a far smaller tailcone anyway, and aircraft 102, 201 and 202 had the bulk of the MEPU assembly complete with Hydrazine tank to fill up most of the void. The fix to the cracking problems was both very simple and quick to implement, and it never became a big deal. The MEPU, as has been mentioned a few times previous, was both useless and unsafe as far as a commercial aircraft goes; being replaced by a ram air turbine.
It's funny, but this is how this wonderful thread started over one month ago by stilton , I for one am so glad that it has both progressed and diversified the way that it has.
As far as charters go I'll leave it up to EXWOK or one of the other guys to answer, as far as flight planning goes. Thanks for your comments BlueConcorde, they always took a ground engineer on RTW charters, and although I never had the pleasure of directly participating in one (although I was on the end of a phone several times when problems occurred en-route)I WAS due to go in 2000, but tragic events in Paris caused that charter to be cancelled. I was however lucky enough to participate in various other charters, my most memorable one was in October 1991, when the World Bank chartered Concorde to Bangkok. The most amazing thing about RTW charters (or earth orbiters, as I would call them) was that the aircraft often returned to London with only a very small handfull of minor defects. The thing about Concorde was the more that she flew, the happier she was, and less likely to catch a cold.
PS. oops, EXWOK is already 'there'
Dude
30th Sep 2010, 15:03
permalink Post: 500
I copied this off M2dude's post a couple of days ago, and tried to answer it all offline without cheating by looking up the answers elsewhere.
1) How many fuel tanks were there on Concorde?
LOL... 13.
I suppose that, for the same reason there was no row 13 in the cabin, somebody decided to name two of the tanks "5A" and "7A", rather than call the tail trim tank (named no.11) number 13.
Yes, I forgot the scavenge tank.
And since it was "BA Concordes only" I didn't want to add the hydrazine tank on the two preprod and the two certification aircraft.
2) How many seats were there?
Good question.
As Nick asked, which seats?
Nominally there were 100 pax seats in the cabin, although originally up to 127 were certified.
Five (three plus two jump seats) in the cockpit.
Cabin seats for the cabin crew.... I honestly don't know. Seven?
Wrong twice... six cabin crew seats, AND I forgot to count the loos!
3) At what approximate altitude and KNOTS EAS was Mach 2 achieved?
Roughly, FL500 and 530 kts.
But not being a pilot I had to check an instant on my flight envelope crib sheet, which I have at hand all the time.....
It seemed pointless to be TOO precise, because that assumed ISA and creeping exactly up the right edge of the envelope.
4) Only one BA Concorde had three different registrations, what was it?
Without looking it up, no idea. My guess is G-BOAF, with a white-tail reg, a "British" reg, and a pseudo-American reg.
IIRC, G-BOAG never had a pseudo-American reg, but I'm not sure without looking it up.
Brain not completely addled, then.
5) What was the maximum permitted altitude in passenger service?
FL600, as certified.
6) How many wheels on the aircraft?
Twelve, if you count the two Spitfire wheels at the back
7) How many flying control modes were there?
Four. Blue, green, mechanical and ... what did we call it? Control jam, CWS?
Ah, thanks, Emergency Flight Control. I always considered it as a separate mode, even if it was virtually never used.
8) How many positions of nose droop were there?
Four. 0\xb0, 5\xb0, 12.5\xb0 and 17.5\xb0 (the latter only on the prototypes, and purely mechanically, after removing a stop, on the other aircraft).
9) What was the first microprocessor application on the aircraft?
No idea... you (M2dude) mentioned a Plessey data acquisition system?
It was after "my time"...
10) How many main electrical sources were there?
Again, not sure... You're presumably are talking about primary sources.
There was an AC constant-drive generator on each engine.
Then there were two DC batteries.
And IIRC there was an AC generator running off the RAT hydraulic generator when pillar came to post.
Reading M2dude's answer, I suppose the emergency generator just ran off the hydraulics, not specifically off the RAT. Far more logical.
Nice one, M2dude!
And certainly not all trivia!
CJ
1) How many fuel tanks were there on Concorde?
LOL... 13.
I suppose that, for the same reason there was no row 13 in the cabin, somebody decided to name two of the tanks "5A" and "7A", rather than call the tail trim tank (named no.11) number 13.
Yes, I forgot the scavenge tank.
And since it was "BA Concordes only" I didn't want to add the hydrazine tank on the two preprod and the two certification aircraft.
2) How many seats were there?
Good question.
As Nick asked, which seats?
Nominally there were 100 pax seats in the cabin, although originally up to 127 were certified.
Five (three plus two jump seats) in the cockpit.
Cabin seats for the cabin crew.... I honestly don't know. Seven?
Wrong twice... six cabin crew seats, AND I forgot to count the loos!
3) At what approximate altitude and KNOTS EAS was Mach 2 achieved?
Roughly, FL500 and 530 kts.
But not being a pilot I had to check an instant on my flight envelope crib sheet, which I have at hand all the time.....
It seemed pointless to be TOO precise, because that assumed ISA and creeping exactly up the right edge of the envelope.
4) Only one BA Concorde had three different registrations, what was it?
Without looking it up, no idea. My guess is G-BOAF, with a white-tail reg, a "British" reg, and a pseudo-American reg.
IIRC, G-BOAG never had a pseudo-American reg, but I'm not sure without looking it up.
Brain not completely addled, then.
5) What was the maximum permitted altitude in passenger service?
FL600, as certified.
6) How many wheels on the aircraft?
Twelve, if you count the two Spitfire wheels at the back
7) How many flying control modes were there?
Four. Blue, green, mechanical and ... what did we call it? Control jam, CWS?
Ah, thanks, Emergency Flight Control. I always considered it as a separate mode, even if it was virtually never used.
8) How many positions of nose droop were there?
Four. 0\xb0, 5\xb0, 12.5\xb0 and 17.5\xb0 (the latter only on the prototypes, and purely mechanically, after removing a stop, on the other aircraft).
9) What was the first microprocessor application on the aircraft?
No idea... you (M2dude) mentioned a Plessey data acquisition system?
It was after "my time"...
10) How many main electrical sources were there?
Again, not sure... You're presumably are talking about primary sources.
There was an AC constant-drive generator on each engine.
Then there were two DC batteries.
And IIRC there was an AC generator running off the RAT hydraulic generator when pillar came to post.
Reading M2dude's answer, I suppose the emergency generator just ran off the hydraulics, not specifically off the RAT. Far more logical.
Nice one, M2dude!
And certainly not all trivia!
CJ
29th Oct 2010, 16:00
permalink Post: 625
hydrazine powered as was the ME "162"
I haven't had time to read all of the posts so I doubt I'm the first person to point out the typo but the ME 163 was the rocket powered interceptor, the ME 262 was the first operation jet fighter...twin engine and powered by jet fuel. Also, the ME 163's were cool but they had a poor operational record of killing more of their pilots (due to the hydrazine instability) more often than they shot down allied bombers or their fighter escorts.
29th Oct 2010, 17:16
permalink Post: 629
ChristiaanJ,
I'm 31yrs old and my knowledge comes from reading as well as the Military and History channels. I totally forgot about the HE-162. My knowledge is trivial in comparison to the info in this blog....so much so that I was nervous to post it. I just couldn't shake the statistics about the speed of the 163 and the number of top German pilots that the hydrazine rockets killed.
Thanks for the info. I am sure it was a typo, and if not, my knowledge is academic as opposed to practical. I have 25hrs of flight training, 15 of which is recreational single-engine sea water landing in a Lake Amphibian. This training is now 14yrs old. As I said, academic/trivial-knowledge, not practical.
I'm 31yrs old and my knowledge comes from reading as well as the Military and History channels. I totally forgot about the HE-162. My knowledge is trivial in comparison to the info in this blog....so much so that I was nervous to post it. I just couldn't shake the statistics about the speed of the 163 and the number of top German pilots that the hydrazine rockets killed.
Thanks for the info. I am sure it was a typo, and if not, my knowledge is academic as opposed to practical. I have 25hrs of flight training, 15 of which is recreational single-engine sea water landing in a Lake Amphibian. This training is now 14yrs old. As I said, academic/trivial-knowledge, not practical.
29th Oct 2010, 18:01
permalink Post: 632
Quote:
|
Originally Posted by
jobpatto
My knowledge is trivial in comparison to the info in this blog....so much so that I was nervous to post it.
|
Quote:
| I just couldn't shake the statistics about the speed of the 163 and the number of top German pilots that the hydrazine rockets killed. |
As mentioned earlier, hydrazine was "tamed" enough in the postwar years to make its use for EPUs in the military feasible (such as the F-16), where the weight gain is more important than the difficulties of handling the stuff.
Even so, just as well it was never used on the in-service Concordes... it's not the kind of product you want around on a civilian airport....
Just imagine a Concorde at the gate.. everybody being cleared away in a wide radius... a few people driving up with goggles, helmets and asbestos suits...
"What IS going on ??" "Oh, nothing, just topping up the APU"....
jodeliste ,
I have Stanley Hooker's book too. If you ever find that tape, put me on the distribution list for the DVD (all costs reimbursed, of course!).
CJ
29th Oct 2010, 18:16
permalink Post: 634
Classic
[FONT='Verdana','sans-serif']ChristiaanJ,[/FONT]
Classic, I love it. You speak with a tone of classic British understatement. I seem to recall that hydrazine in the early-to-mid 40's would burn through any type of protective clothing w/o even a spark....although I wouldn't swear to it. Regardless, I can only imagine Concorde passengers, sipping champagne and watching ground-crew members in hazmat suits pumping 'something' into their plane. My great aunt and uncle flew on the Concorde dozens of times and never described such a scene. I could only imagine that it would be unnerving to the passengers, at best!
Thank you for the comments and kind words.
Classic, I love it. You speak with a tone of classic British understatement. I seem to recall that hydrazine in the early-to-mid 40's would burn through any type of protective clothing w/o even a spark....although I wouldn't swear to it. Regardless, I can only imagine Concorde passengers, sipping champagne and watching ground-crew members in hazmat suits pumping 'something' into their plane. My great aunt and uncle flew on the Concorde dozens of times and never described such a scene. I could only imagine that it would be unnerving to the passengers, at best!
Thank you for the comments and kind words.