---
created_at: '2014-09-06T03:02:47.000Z'
title: Epic Forum Thread on Concorde (2010)
url: http://www.pprune.org/tech-log/423988-concorde-question.html
author: idlewords
points: 115
story_text: ''
comment_text: 
num_comments: 49
story_id: 
story_title: 
story_url: 
parent_id: 
created_at_i: 1409972567
_tags:
- story
- author_idlewords
- story_8277343
objectID: '8277343'

---
[![Reply](/images/buttons/reply.gif)](https://www.pprune.org/newreply.php?do=newreply&noquote=1&p=5866333)
Page 1 of
103

**1**

[2](https://www.pprune.org/tech-log/423988-concorde-question-2.html "Show results 21 to 40 of 2,041")[3](https://www.pprune.org/tech-log/423988-concorde-question-3.html "Show results 41 to 60 of 2,041")[4](https://www.pprune.org/tech-log/423988-concorde-question-4.html "Show results 61 to 80 of 2,041")[5](https://www.pprune.org/tech-log/423988-concorde-question-5.html "Show results 81 to 100 of 2,041")[11](https://www.pprune.org/tech-log/423988-concorde-question-11.html "Show results 201 to 220 of 2,041")[51](https://www.pprune.org/tech-log/423988-concorde-question-51.html "Show results 1,001 to 1,020 of 2,041")[101](https://www.pprune.org/tech-log/423988-concorde-question-101.html "Show results 2,001 to 2,020 of 2,041")
[\>](https://www.pprune.org/tech-log/423988-concorde-question-2.html "Next Page - Results 21 to 40 of 2,041")
[Last
**»**](https://www.pprune.org/tech-log/423988-concorde-question-103.html "Last Page - Results 2,041 to 2,041 of 2,041")

 

[Search this
Thread](https://www.pprune.org/tech-log/423988-concorde-question.html#goto_threadsearch)
![Old](/images/statusicon/post_old.gif) 13th Aug 2010, 04:32  
\#[**1**](https://www.pprune.org/5866333-post1.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5866333 "Link to this Post")**)
[stilton](https://www.pprune.org/members/87315-stilton)

Thread Starter

  

Join Date: Apr 2004

Location: Planet Earth

Posts: 1,634

**Concorde question**

Considering the era in which the Concorde was produced I am curious as
to why there was no APU fitted. It would seem to have been quite an
inconvenience at times.  
  
  
Was there ever any consideration given to fitting one and was the
decision against the installation solely a weight issue ?

![stilton is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5866333)
![Old](/images/statusicon/post_old.gif) 13th Aug 2010, 09:45  
\#[**2**](https://www.pprune.org/5866720-post2.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5866720 "Link to this Post")**)
[M2dude](https://www.pprune.org/members/218153-m2dude)  

Join Date: Jan 2008

Location: FL 600. West of Mongolia

Posts: 456

  
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
![](https://www.pprune.org/images/smilies/smile.gif "Smilie")) 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.
![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

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 theproblem 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.

![M2dude is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5866720)
![Old](/images/statusicon/post_old.gif) 13th Aug 2010, 16:07  
\#[**3**](https://www.pprune.org/5867539-post3.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5867539 "Link to this Post")**)
[galaxy flyer](https://www.pprune.org/members/62324-galaxy-flyer)  

Join Date: Dec 2002

Location: Where the Quaboag River flows, USA

Age: 65

Posts: 3,302

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.

![galaxy flyer is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5867539)
![Old](/images/statusicon/post_old.gif) 13th Aug 2010, 18:53  
\#[**4**](https://www.pprune.org/5867846-post4.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5867846 "Link to this Post")**)
[M2dude](https://www.pprune.org/members/218153-m2dude)  

Join Date: Jan 2008

Location: FL 600. West of Mongolia

Posts: 456

  
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.![](https://www.pprune.org/images/smilies/smile.gif
"Smilie")

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.

![M2dude is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5867846)
![Old](/images/statusicon/post_old.gif) 13th Aug 2010, 22:14  
\#[**5**](https://www.pprune.org/5868196-post5.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5868196 "Link to this Post")**)
[galaxy flyer](https://www.pprune.org/members/62324-galaxy-flyer)  

Join Date: Dec 2002

Location: Where the Quaboag River flows, USA

Age: 65

Posts: 3,302

**M2dude**  
  
Thanks for the reply, Concorde expertise is always interesting. I should
not have called the F-16 Emergency Power Unit a RAT, it is indeed not.
The Concorde RAT was located aft between the engine pods, correct?  
  
What I found interesting is that the AC generators would remain on-line
at all; they drop instantaneously at subsonic speeds and the associated
N2 rpm. I believe the hydraulics on the 747 will power flight controls
down to a pretty low IAS.  
  
Four engine flameout is a very unlikely event, unless one runs into a
volcanic cloud.

![galaxy flyer is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5868196)
![Old](/images/statusicon/post_old.gif) 13th Aug 2010, 23:36  
\#[**6**](https://www.pprune.org/5868330-post6.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5868330 "Link to this Post")**)
[stilton](https://www.pprune.org/members/87315-stilton)

Thread Starter

  

Join Date: Apr 2004

Location: Planet Earth

Posts: 1,634

Thanks M2Dude for your interesting and informative reply.

![stilton is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5868330)
![Old](/images/statusicon/post_old.gif) 14th Aug 2010, 21:17  
\#[**7**](https://www.pprune.org/5870039-post7.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5870039 "Link to this Post")**)
[TURIN](https://www.pprune.org/members/46562-turin)  

Join Date: Feb 2002

Location: UK

Age: 52

Posts: 2,445

For what it's worth, I read a book years ago. "By the Rivers of Babylon"
I think it was.  
It involved a couple of El-Al (Yes I know hard to believe) Concordes
that had APUs fitted in the area normally used as the forward baggage
hold. Small it would have to be to fit methinks.  
  
No idea if the author had researched it or just made it up to fit the
story.

![TURIN is offline](/images/statusicon/user_offline.gif)   [![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5870039)
![Old](/images/statusicon/post_old.gif) 14th Aug 2010, 23:15  
\#[**8**](https://www.pprune.org/5870216-post8.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5870216 "Link to this Post")**)
[M2dude](https://www.pprune.org/members/218153-m2dude)  

Join Date: Jan 2008

Location: FL 600. West of Mongolia

Posts: 456

  
Thanks very much for your comments. It's true, that while supersonic, a
windmilling Olympus engine would have sufficient N2 to keep all servics
on line. (The hydraulic systems on Concorde also operated at 4000 PSI).
The RAT itself was 'said' to be good down to approach speeds,
fortunately we never had to find out if that was true. (Although the
thing was tested routinely using a hydraulic rig to drive it and check
the variable pitch speed control). Thr RAT was in fact located and
stowed in the fwd part of the R/H inboard elevon Powered Flying Control
Unit Fairing. It was an absolute work of art by Dowty, to make the
device fit into such a small space.  
Yep, an ash cloud would be particularly bad news, particularly at FL600
![](https://www.pprune.org/images/smilies/thumbs.gif "Thumb")  
Stlton  
You are most welcome, thank you for posting this topic also. These
forums are a wonderful way for all of us out there in the aviation world
to share and learn interesting information from each
other.![](https://www.pprune.org/images/smilies/smile.gif "Smilie")  
TURIN  
I remember reading By the Rivers of Babylon many MANY years ago. The
terrorists, I seem to remember, had a bomb fitted inside Tank 11 (the
rear trim tank) during construction 'before it was welded shut'. Not
sure if the author had researched how aircraft were built, but still I
guess it sold a copy or two. (Well at least you and I read
it).![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

Galaxy FlyerThanks very much for your comments. It's true, that while
supersonic, a windmilling Olympus engine would have sufficient N2 to
keep all servics on line. (The hydraulic systems on Concorde also
operated at 4000 PSI). The RAT itself was 'said' to be good down to
approach speeds, fortunately we never had to find out if that was true.
(Although the thing was tested routinely using a hydraulic rig to drive
it and check the variable pitch speed control). Thr RAT was in fact
located and stowed in the fwd part of the R/H inboard elevon Powered
Flying Control Unit Fairing. It was an absolute work of art by Dowty, to
make the device fit into such a small space.Yep, an ash cloud would be
particularly bad news, particularly at FL600StltonYou are most welcome,
thank you for posting this topic also. These forums are a wonderful way
for all of us out there in the aviation world to share and learn
interesting information from each other.TURINI remember reading By the
Rivers of Babylon many MANY years ago. The terrorists, I seem to
remember, had a bomb fitted inside Tank 11 (the rear trim tank) during
construction 'before it was welded shut'. Not sure if the author had
researched how aircraft were built, but still I guess it sold a copy or
two. (Well at least you and I read it).

![M2dude is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5870216)
![Old](/images/statusicon/post_old.gif) 15th Aug 2010, 15:22  
\#[**9**](https://www.pprune.org/5871287-post9.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5871287 "Link to this Post")**)
[Christo](https://www.pprune.org/members/91749-christo)  

Join Date: Jun 2004

Location: Garsfontein, Pretoria

Posts: 76

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.
![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

I think he got confused with the F16 JFS which does use hydrazine but
like you mentioned, is most certainly not a RAT

![Christo is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5871287)
![Old](/images/statusicon/post_old.gif) 15th Aug 2010, 15:54  
\#[**10**](https://www.pprune.org/5871342-post10.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5871342 "Link to this Post")**)
[ChristiaanJ](https://www.pprune.org/members/105267-christiaanj)  

Join Date: Jan 2005

Location: France

Posts: 2,319

**TURIN**,  
I've read "By the Rivers of Babylon" too..... and there is some fact
behind the fiction.  
  
History does not relate if and where the El Al Concordes would have had
APUs.  
  
However, history DOES relate, that the two Concordes ordered by Iran Air
WOULD have had APUs (which would have made sense in the Middle East).  
Now, Iran Air was the very last company to cancel its orders, and by the
time they did, Concorde 214 (now G-BOAG) and 216 (now G-BOAF) were
already well underway (they ended up flying initially as white tails).  
  
As a result, both 214 and 216 still have the mounting holes and fittings
for an APU. Don't ask me where, but experts know where to find them to
this day....

![ChristiaanJ is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5871342)
![Old](/images/statusicon/post_old.gif) 16th Aug 2010, 12:09  
\#[**11**](https://www.pprune.org/5872914-post11.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5872914 "Link to this Post")**)
[M2dude](https://www.pprune.org/members/218153-m2dude)  

Join Date: Jan 2008

Location: FL 600. West of Mongolia

Posts: 456

  
Both A/C 214 (OAG) and 216 (OAF) were Variant 192 A/C (British Unsold
A/C). 216 was later converted to a 102 (British Airways) Variant, where
214 more or less stayed as a Variant 192. I'm not disputing what you say
about possible APU mountings (I guess it would HAVE to be at the front
section of the lower cargo hold somewhere) but I for one have certainly
never seen any evidence of them. I'm still trying to imagine where the
air inlet and exhausts would have to be arranged, not to mention
pneumatic services ducting/hydraulics. Wouldn't it be interesting to
find out? ![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

ChristiaanJBoth A/C 214 (OAG) and 216 (OAF) were Variant 192 A/C
(British Unsold A/C). 216 was later converted to a 102 (British Airways)
Variant, where 214 more or less stayed as a Variant 192. I'm not
disputing what you say about possible APU mountings (I guess it would
HAVE to be at the front section of the lower cargo hold somewhere) but I
for one have certainly never seen any evidence of them. I'm still trying
to imagine where the air inlet and exhausts would have to be arranged,
not to mention pneumatic services ducting/hydraulics. Wouldn't it be
interesting to find out?

![M2dude is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5872914)
![Old](/images/statusicon/post_old.gif) 16th Aug 2010, 15:17  
\#[**12**](https://www.pprune.org/5873326-post12.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5873326 "Link to this Post")**)
[Dan Winterland](https://www.pprune.org/members/2724-dan-winterland)  

Join Date: Jun 2001

Location: Fragrant Harbour

Posts: 4,484

The original BOAC/BA VC10s didn't have APUs either. The ones converted
to K4s for the RAF had to have them fitted.

![Dan Winterland is online now](/images/statusicon/user_online.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5873326)
![Old](/images/statusicon/post_old.gif) 16th Aug 2010, 15:18  
\#[**13**](https://www.pprune.org/5873329-post13.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5873329 "Link to this Post")**)
[ChristiaanJ](https://www.pprune.org/members/105267-christiaanj)  

Join Date: Jan 2005

Location: France

Posts: 2,319

Quote:

**M2dude** [![View
Post](/images/buttons/viewpost.gif)](https://www.pprune.org/tech-log/423988-concorde-question.html#post5872914)

Originally Posted by

![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

Wouldn't it be interesting to find out?

  
I can try asking around, but can't remember my original source - it
probably came up during a discussion of the MEPU on Delta Golf or on 01
several years ago. I very much doubt it would be mentioned explicitly in
the SRM (Structural Repair Manual).  
IIRC the MEPU lived in the tail (I'll look it up), so it's not
impossible the APU was planned in the same location.

It would be, yes\!I can try asking around, but can't remember my
original source - it probably came up during a discussion of the MEPU on
Delta Golf or on 01 several years ago. I very much doubt it would be
mentioned explicitly in the SRM (Structural Repair Manual).IIRC the MEPU
lived in the tail (I'll look it up), so it's not impossible the APU was
planned in the same location.

![ChristiaanJ is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5873329)
![Old](/images/statusicon/post_old.gif) 16th Aug 2010, 16:37  
\#[**14**](https://www.pprune.org/5873511-post14.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5873511 "Link to this Post")**)
[ChristiaanJ](https://www.pprune.org/members/105267-christiaanj)  

Join Date: Jan 2005

Location: France

Posts: 2,319

  
In the meantime, here's the MEPU exhaust in the tailcone of Delta Golf,
courtesy of Neil Walker.  
  
![](http://www.concordeproject.com/photos/2006/060306_8.jpg)  
  
CJ

Just looked up the MEPU in the 01 AFM, and indeed it's located in the
tail cone. I'll scan the page this evening.In the meantime, here's the
MEPU exhaust in the tailcone of Delta Golf, courtesy of Neil Walker.CJ

![ChristiaanJ is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5873511)
![Old](/images/statusicon/post_old.gif) 16th Aug 2010, 19:53  
\#[**15**](https://www.pprune.org/5873899-post15.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5873899 "Link to this Post")**)
[ChristiaanJ](https://www.pprune.org/members/105267-christiaanj)  

Join Date: Jan 2005

Location: France

Posts: 2,319

  
  
![](http://img.photobucket.com/albums/v324/ChristiaanJ/MEPU011.gif)  
  
![](http://img.photobucket.com/albums/v324/ChristiaanJ/MEPU012.gif)

Just scanned this off the Concorde 01 (G-AXDN) Flight Manual, and
cropped as much as possible.

![ChristiaanJ is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5873899)
![Old](/images/statusicon/post_old.gif) 17th Aug 2010, 10:50  
\#[**16**](https://www.pprune.org/5874791-post16.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5874791 "Link to this Post")**)
[M2dude](https://www.pprune.org/members/218153-m2dude)  

Join Date: Jan 2008

Location: FL 600. West of Mongolia

Posts: 456

**through a fuel tank**, (Remember that tank 11 occupied the entire rear
fuselage between the rear cargo aft wall and the front of the tail
cone). then I don't think that this was really on. (It's quite possible
of course that I'm missing something here, it comes with age
![](https://www.pprune.org/images/smilies/badteeth.gif "Bad teeth")).  
As far as the MEPU goes, all it really did was drive 2 hydraulic pumps;
the Green System then powering the 40 KVA emergency generator; unless
you are going to use the APU for engine starting and ground air
conditioning, then I honestly don't think that there would be much
point. It's interesting also to note that the MPU, being a rocket motor,
needed no air intake, and as it was not driving any huge loads, the
exhaust duct dould be quite narrow.
![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

Hi Christiaan, yes THAT was the MEPU (Good photo of G-BBDG by the way).
As far as fitting an APU in the tail cone, I still personally think that
UNLESS you are prepared to pass a sizable pneumatic duct, (Remember that
tank 11 occupied the entire rear fuselage between the rear cargo aft
wall and the front of the tail cone). then I don't think that this was
really on. (It's quite possible of course that I'm missing something
here, it comes with age).As far as the MEPU goes, all it really did was
drive 2 hydraulic pumps; the Green System then powering the 40 KVA
emergency generator; unless you are going to use the APU for engine
starting and ground air conditioning, then I honestly don't think that
there would be much point. It's interesting also to note that the MPU,
being a rocket motor, needed no air intake, and as it was not driving
any huge loads, the exhaust duct dould be quite narrow.

![M2dude is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5874791)
![Old](/images/statusicon/post_old.gif) 17th Aug 2010, 14:33  
\#[**17**](https://www.pprune.org/5875273-post17.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5875273 "Link to this Post")**)
[ChristiaanJ](https://www.pprune.org/members/105267-christiaanj)  

Join Date: Jan 2005

Location: France

Posts: 2,319

  
  
Nice set of photos of "The Thing" here :  
[MEPU at MAE at le
Bourget](http://f-wtss.over-blog.com/article-15380845.html).  
This one is at the Air and Space Museum at Le Bourget, near Paris. My
guess is that is was a spare, since the manufacturing date is 1973. 'SA
flew in January '73 and 'SB in December '73.  
IIRC, Delta Golf arrived at Brooklands with the MEPU still in place; I
might have a photo.  
  
As to the installation, we're obviously thinking along the same
lines....  
  
However, there were already several conduits through tank 11, such as
hydraulics for the tail wheel, various electrics, and the 'backbone'
fuel manifolds, that ended at the fuel jettison port in the tailcone.  
A couple of fairly substantial air ducts would only have displaced a few
hundred kgs of fuel at the most, out of the more than 10,000 kgs in tank
11.  
  
And yes, of course, the whole point of the APU would be to have
independent ground start and ground airco available, so clearly an APU
would have been bigger and heavier than the MEPU (which was only just
over 80 lbs), plus the problem of the air intake and bigger exhaust.  
I'd have to get the drawings out to see how easy or difficult it would
have been to fit one in the available space.  
  
Since the tailcone was BAC, and both 214 and 216 were built at Filton, I
wonder if anybody there still remembers?

M2dude,Nice set of photos of "The Thing" here :This one is at the Air
and Space Museum at Le Bourget, near Paris. My guess is that is was a
spare, since the manufacturing date is 1973. 'SA flew in January '73 and
'SB in December '73.IIRC, Delta Golf arrived at Brooklands with the MEPU
still in place; I might have a photo.As to the installation, we're
obviously thinking along the same lines....However, there were already
several conduits through tank 11, such as hydraulics for the tail wheel,
various electrics, and the 'backbone' fuel manifolds, that ended at the
fuel jettison port in the tailcone.A couple of fairly substantial air
ducts would only have displaced a few hundred kgs of fuel at the most,
out of the more than 10,000 kgs in tank 11.And yes, of course, the whole
point of the APU would be to have independent ground start and ground
airco available, so clearly an APU would have been bigger and heavier
than the MEPU (which was only just over 80 lbs), plus the problem of the
air intake and bigger exhaust.I'd have to get the drawings out to see
how easy or difficult it would have been to fit one in the available
space.Since the tailcone was BAC, and both 214 and 216 were built at
Filton, I wonder if anybody there still remembers?

![ChristiaanJ is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5875273)
![Old](/images/statusicon/post_old.gif) 18th Aug 2010, 12:27  
\#[**18**](https://www.pprune.org/5877465-post18.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5877465 "Link to this Post")**)
[M2dude](https://www.pprune.org/members/218153-m2dude)  

Join Date: Jan 2008

Location: FL 600. West of Mongolia

Posts: 456

  
Thanks for the MEPU link, that really brings back memories (or was that
nightmares ![](https://www.pprune.org/images/smilies2/icon_rolleyes.gif
"Roll Eyes (Sarcastic)")). 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
![](https://www.pprune.org/images/smilies/smile.gif "Smilie")

ChristiaanJThanks 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

![M2dude is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5877465)
![Old](/images/statusicon/post_old.gif) 18th Aug 2010, 16:19  
\#[**19**](https://www.pprune.org/5878005-post19.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5878005 "Link to this Post")**)
[Biggles78](https://www.pprune.org/members/297800-biggles78)  

Join Date: Apr 2009

Location: \`

Posts: 301

![](https://www.pprune.org/images/smilies/eek.gif "EEK!") No, I am
really not that stupid to think it was all used for trim but I am
beginning to realise just how little I knew about this technological
wonder of the skies. Also wish someone had recorded her being rolled
(like the B707 when being displayed). Now that would be something that
would stand along side the noise abatement takeoff or maybe not. The T/O
is impressive\!\!  
  
M2dude and ChristiaanJ, please keep posting any anecdotes that you
remember about this incredible aeroplane. It really is fascinating
learning about the technical side from those who actually knew her.

10,000kg in a trim tank?No, I am really not that stupid to think it was
all used for trim but I am beginning to realise just how little I knew
about this technological wonder of the skies. Also wish someone had
recorded her being rolled (like the B707 when being displayed). Now that
would be something that would stand along side the noise abatement
takeoff or maybe not. The T/O is impressive\!\!M2dude and ChristiaanJ,
please keep posting any anecdotes that you remember about this
incredible aeroplane. It really is fascinating learning about the
technical side from those who actually knew her.

![Biggles78 is offline](/images/statusicon/user_offline.gif)   [![Reply
With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5878005)
![Old](/images/statusicon/post_old.gif) 18th Aug 2010, 21:24  
\#[**20**](https://www.pprune.org/5878555-post20.html)
(**[permalink](https://www.pprune.org/tech-log/423988-concorde-question.html#post5878555 "Link to this Post")**)
[ChristiaanJ](https://www.pprune.org/members/105267-christiaanj)  

Join Date: Jan 2005

Location: France

Posts: 2,319

  
  
Re the MEPU at the Le Bourget museum...  
The story I just got was that it was taken off F-WTSA or F-WTSB at
Roissy for a fault and replaced (both 'SA and 'SB operated out of Roissy
around '74 / '75 for things like route proving, etc.).  
It got left on a shelf in a store, and was only discovered again in 2003
during the "big clean-out" and was saved 'in extremis' by somebody who
recognised it for what it was, stopped it from being 'binned' and took
it over to the museum.  
  

Quote:

Originally Posted by **Biggles78**

10,000kg in a trim tank? No, I am really not that stupid to think it was
all used for trim

  
So yes, you're right, essentially all of it was "useable" fuel, it did
not serve only for the trim.  
  

Quote:

Also wish someone had recorded her being rolled (like the B707 when
being displayed).  
Jock Lowe seems to have stated there is a photo.... and we all still
wonder if there is some footage taken from the Lear Jet during the
filming of "Airport 79". But none is publicly known to exist ... we just
know it's been done\!

M2dude,Re the MEPU at the Le Bourget museum...The story I just got was
that it was taken off F-WTSA or F-WTSB at Roissy for a fault and
replaced (both 'SA and 'SB operated out of Roissy around '74 / '75 for
things like route proving, etc.).It got left on a shelf in a store, and
was only discovered again in 2003 during the "big clean-out" and was
saved 'in extremis' by somebody who recognised it for what it was,
stopped it from being 'binned' and took it over to the museum.Initially
of couse it was. It was not until the return to subsonic, towards the
end of the flight, that the contents of the n° 11 trim tank were moved
forward again to the other tanks.So yes, you're right, essentially all
of it was "useable" fuel, it did not serve only for the trim.Don't we
all....Jock Lowe seems to have stated there is a photo.... and we all
still wonder if there is some footage taken from the Lear Jet during the
filming of "Airport 79". But none is publicly known to exist ... we just
know it's been done\!

![ChristiaanJ is offline](/images/statusicon/user_offline.gif)  
[![Reply With
Quote](/images/buttons/quote.gif)](https://www.pprune.org/newreply.php?do=newreply&p=5878555)

[![Reply](/images/buttons/reply.gif)](https://www.pprune.org/newreply.php?do=newreply&noquote=1&p=5878555)
Page 1 of
103

**1**

[2](https://www.pprune.org/tech-log/423988-concorde-question-2.html "Show results 21 to 40 of 2,041")[3](https://www.pprune.org/tech-log/423988-concorde-question-3.html "Show results 41 to 60 of 2,041")[4](https://www.pprune.org/tech-log/423988-concorde-question-4.html "Show results 61 to 80 of 2,041")[5](https://www.pprune.org/tech-log/423988-concorde-question-5.html "Show results 81 to 100 of 2,041")[11](https://www.pprune.org/tech-log/423988-concorde-question-11.html "Show results 201 to 220 of 2,041")[51](https://www.pprune.org/tech-log/423988-concorde-question-51.html "Show results 1,001 to 1,020 of 2,041")[101](https://www.pprune.org/tech-log/423988-concorde-question-101.html "Show results 2,001 to 2,020 of 2,041")
[\>](https://www.pprune.org/tech-log/423988-concorde-question-2.html "Next Page - Results 21 to 40 of 2,041")
[Last
**»**](https://www.pprune.org/tech-log/423988-concorde-question-103.html "Last Page - Results 2,041 to 2,041 of 2,041")  
  
**«** [Previous
Thread](https://www.pprune.org/tech-log/423988-concorde-question-prev-thread.html)
| [Next
Thread](https://www.pprune.org/tech-log/423988-concorde-question-next-thread.html)
**»** Thread Tools Search this Thread ![Show Printable
Version](/images/buttons/printer.gif) [Show Printable
Version](https://www.pprune.org/tech-log/print-423988-concorde-question.html)![Email
this Page](/images/buttons/sendtofriend.gif) [Email this
Page](https://www.pprune.org/sendmessage.php?do=sendtofriend&t=423988)
**Search this Thread**:  
  
[Advanced
Search](https://www.pprune.org/search.php?searchthreadid=423988)  
[![](/images/buttons/collapse_thead.gif)](https://www.pprune.org/tech-log/423988-concorde-question.html#top)
Posting Rules

You **may not** post new threads

You **may not** post replies

You **may not** post attachments

You **may not** edit your posts

**On**[BB code](https://www.pprune.org/misc.php?do=bbcode)
is**On**[Smilies](https://www.pprune.org/misc.php?do=showsmilies)
are**On**[\[IMG\]](https://www.pprune.org/misc.php?do=bbcode#imgcode)
code is

HTML code is
**Off**

**Off**[Trackbacks](https://www.pprune.org/misc.php?do=linkbacks#trackbacks)
are**Off**[Pingbacks](https://www.pprune.org/misc.php?do=linkbacks#pingbacks)
are**Off**[Refbacks](https://www.pprune.org/misc.php?do=linkbacks#refbacks)
are [Forum Rules](https://www.pprune.org/misc.php?do=showrules)  
  

All times are GMT. The time now is

08:49

.
