1) Effectively it was (not the skin, but the TAT probe. The highest temp rise would be at the stagnation point so one can be confident that TAT is a realistic answer for max skin temp).

2) AFAIK pretty standard:

Q from pitots
S from statics
T from temp probe

Modified by ADC for position error. It's possible that ADC used beta inputs and I'm sure it used alpha inputs to achieve this.

Possibly daft question about expansion joints
 

The exhibit at the Seattle Museum of Flight (Alpha Golf, I think) has the story of the flight engineer who placed his cap in what's called "the expansion joint."

But I can't figure out how the "expansion joint" got itself closed when the airplane was cold, and open when the airplane was hot. Seems backwards to me.

In my mind, the cool airplane has smaller parts, and therefore larger gaps in the joints.

What am I missing?

(I shudder to ask this question, since I have the tingle on the back of my neck that usually tells me I'm missing something simple.)

Sort of .... the aircraft expanded when at Mach 2, so it grew in length etc. This growth translated itself into the gap that the hat was put in. When it cooled on decel/descent, the gap closed wedging in the hat.

Simples...

Yep that's it.

Imagine it this way - the outside of the hull is hot and expands. The floor and other interior components, however, are about 100 degs cooler and so not subject to the same expansion. In a very simplified description, if you imagine the floor on rollers but attached at one end then you'll see a gap at the other end when the exterior hull stretches. That's the effect you see when the expansion gap appears aft of the FE's panel in supersonic flight. (The floor is, by the way, not just sitting on rollers.....)

Electrical looms had a little sag between fixed points if they were attached to 'expanding' parts of the airframe.

And so on.

It's amazing there was ever any hydraulic fluid left on board if you consider the stresses and aggro involved in routing the pipes and hoses.

Thanks Ex Wok but now I'm even more confused!

1) So there is a direct temp reading, from the TAT probe. But where is TAT probe? Is it in the needle nose probe that also measures pitot/static for the intake computers? And how many TAT sensors are there (failure of a single one if that's all there is would not be good)?

2) Mach comes from dynamic pressure (pitots), from static ports, and from temp. But what temp? OAT perhaps?

This seems to have got lost at the bottom of the last page. Any answers?

http://i1080.photobucket.com/albums/.../Picture16.jpg

SSD:- this answers your question on where the TAT probes were located. Strictly, you don't need temperature to calculate Mach as it is independent of temperature when expressed in EAS (or CAS) terms.

Shane:
The "crown modifications" were external straps to be applied to the upper part of the fuselage to extend its life in those areas which had been designed to safe life concepts - basically the Aerospatiale bits since BAe designed their bits according to damage tolerance rules. It wasn't a small job, but I'm afraid I can't tell you how many aircraft were modified.

Thanks Clive but I'm still going around in circles. Those sensors measure OAT do they not? They are spaced out from the (hot) skin to do that, presumably.

Can you confirm just how that tells the crew the skin temp? Are there no direct-reading temp sensors on or under the nose skin or in the probe?

So far as I know, they were standard TAT measurement instruments, so they gave Total Air Temperature directly.

There was, so far as I recall, no measure of skin temperature - the aircraft limit (Tmo) was simply based on a measured TAT of 400 degK. The implied limits on skin temperature at various points were built into the design cases.

No part of the skin will be warmer than the TAT probe, if that helps......

Here's the cockpit temp gauge I photgraphed today:

http://i18.photobucket.com/albums/b132/GZK6NK/TAT1.jpg

So the TAT probe provides TAT (obviously) which effectively is skin temp (as evidenced by the TMO legend of 127C just below the TAT window?).

(TAT being static air temp plus the temp due adiabatic heating).

For some reason I seem to remember a picture of a Concorde Cockpit with four INS sets side by side, was this ever the case or just my imagination ?


Also, were the INS installed specially developed for Concorde or were they the same as fitted in the B747 for example.


Finally was GPS updating to the INS position ever developed and installed ?

http://i1080.photobucket.com/albums/.../SkinTemps.jpg

Not exactly skin temperature, just the maximum temperature on the nose. The rest of the aircraft was cooler.

Indeed, but as a pilot you look after the nose temp... and the rest of the aeroplane will be just fine.

So TAT is skin temp at the probes, which are rearward of the hottest skin according to that diagram. Was there a 'compensation' built into the TAT readout to account for the relatively rearward position of the TAT probes?

And.. How was static temp readout derived?

Sorry to keep asking, but I really want to understand this!

Thanks.

Er - no, the TAT probes measure just what they say Total Air Temperature.

They are mounted off the skin and in freestream, so they measure the same temperature as would a probe on the nose.

Somewhere near the nose (not exactly on it, as the aircraft flies with a small AoA) there will be a 'stagnation' streamline where the oncoming air is brought to rest. At this point the skin temperature will be equal to the stagnation temperature (TAT). Behind that it gets more complicated! The skin temperature would depend on SAT, local Mach No, local skin friction coefficient (Mach and Re dependent, so varies with distance from nose), amount of heat radiated into space (paint colour!) and the amount of structure available to conduct heat away from the skin into the fuel (so roughly varying with thickness/chord and fuel distribution perhaps?

Static temperature and total temperature are related by a simple expression:

TAT = SAT *(1+0.2m^2) all in deg K

So in the troposphere at ISA +5 and Mach 2, SAT = 222 and TAT = 400.

G-AXDN and G-BBDG in the UK have the 3 INS controllers across the front of the pedestal under the primary engineer gauges. I can only suggest that this was dow to the Pilots being the navigators and the engineer being the engineer. Once in Airline service ensuring each crew member has an INS control panel greatly speeded up the checks. Of note 001/002 actually had a navigator in the cockpit behind the Captain, rather than the jump seat.

Standard spec INS systems for that time. Someone may have more information, but they were upgraded over time to having very little memory requiring load from a data card, to having memory for the core routes the aircraft flew in the system permanently, but still only 10 Waypoints could be loaded live at any one time.


GPS would been a complete replacement for an INS. The clever thing the INS system could do was use DME updating to refine their position when in range of a ground station....a bit like how your smart phone can work out your location by cell mast triangulation if it does not have a GPS receiver in it.

Very relevant for the current time: it was a similar INS system that was hashed into the Vulcan to allow it to find the falklands for the blackbuck raids.

Me too, knew most of the Brit. characters, too.

(Only recently shown downundda )

747-400 used GPS to update INS as well as DME when within range. Not a replacement.
At least the ones I was familiar with.

..a bit like the space shuttle evolved to using GPS in addition to the tried and tested systems. Very interesting.

OK, so the skin temperature at the stagnation point will be equal to TAT. This can be taken as the hottest part of the aircraft (behind it, the skin temperature will be less than the TAT).

The temperature shown in the top window of the flight deck gauge is TAT, with the legend 'TMO 128C' beneath it. So the aircraft was flown with reference to TAT, and provided TAT was no greater than 128C then the skin rearward of the stagnation point would be <128C?

All modern jet transports still use INS, it's output is used for more than just navigation, e.g. Attitude indicator, vertical speed input and others.


GPS (and other sources) merely update and refine the INS position.


I am sure Concorde would have done the same.

Shaggy Sheep Driver:


Yes!

:ok:

Thanks EXWOK! :ok:

Minor correction, though: TMO was 127, not 128.

Indeed. Typed in a hurry. Didn't even check my own photo of the temp gauge which clearly shows 'TMO 127C'.

Hi,

Concorde creator passed ...
Le Figaro - International : Le Concorde orphelin de son crateur
Google Traduction

Oh dear that is sad news.
Henri was one of my favourite Frenchmen. Not only was he a very fine engineer but also a very nice guy.
Maybe stretching it a bit to describe him as the creator of Concorde, but he was certainly one of the principal midwives on the French side.

Hi,


I have an operational question regarding flight crews and aircraft. For routes between Europe and NYC, did crews fly roundtrip flights each day? Or would they layover before returning?

Layover: BA001 landed as BA002 was taxying out, so a there and back was impossible with those timings.

In the days of BA001,2,3&4 operations it was possible to operate BA002 JFK-LHR then BA003 LHR-JFK and this occasionally happened if there was a sudden crew shortage or other disruption.

I did it once and it was a heavy day's work.......

The TAT thing
 

TAT varies with the square of Mach Number and SAT, and although all temperatures for calculation purposes are obviously ABSOLUTE temperature, they are 'converted back' to °C here. So shown below are a range of TATs shown at four different Mach numbers and three specific SATs (or OAT if you prefer). Altitudes can be assumed as being in the lower stratosphere (ie. above tropopause) and ISA relates to International Standard Atmosphere. ISA is of course -56.25°C, ISA -5 is -61.25°C and ISA +5 is -51.25°C.

MACH 0.5.ISA -5: TAT = -50.6°C. ISA: TAT = -45.3°C. ISA +5 TAT = -40°C
MACH 1.0. ISA -5: TAT = -18.5°C. ISA: TAT = -12.5°C. ISA +5 TAT = -6.5°C
MACH 1.5. ISA -5: TAT = 34.8°C. ISA: TAT = 42°C. ISA +5 TAT = 49.3°C
MACH 2.0. ISA -5: TAT = 109.5°C. ISA: TAT =118.6°C. ISA +5 TAT = 127.6°C

Hopefully it all makes a little more sense with some 'real' numbers. You can see that as Mach Number increases the gap between SAT and TAT increases hugely. The Mach 2, ISA +5 case was particularly significant for Concorde, as it breached the 127°C/400°K airframe temperature limit (TMO) and Mach Number would therefore be automatically reduced by the autopilot. (An overspeed warning would be generated at TMO +7 (134.°C). Fortunately sustained ISA +5 or above conditions were relatively rare over the North Atlantic but not unheard of either.

INS
 

stilton

Actually not technically correct mate. The generation(s) of aircraft after Concorde does not use INS as such at all. They either use an Inertial REFERENCE System (IRS) or an Air Data and Inertial Reference System (ADIRS). In both cases inertial data, such as attitude, present position, heading (both true and SYNTHESISED magnetic) acceleration data etc. are output to various user systems. (eg. FMS, EFIS, Autopilot etc.). Wind data, being a function of True Air Speed (TAS) and Ground Speed (G/S)requires in the IRS case TAS data to be input into the IRS from an Air Data Compter, whereas in the ADIRS case we can have muliple ADCs/IRUs effectively crammed into one box, and so wind is kept 'in house'. In either case the autopilot steering signals (LNAV/VNAV) come from the FMS and NOT the IRS. (If you like you could say that an INS knows where it is and where it wants to go, where an IRS just knows where it is and hasn't a CLUEwhere it's going to. In all cases GPS data is fed into the FMS itself, as 'just another input'.
Although Concorde HAD no GPS, (The most difficult part was always finding a part of the upper fuselage where chunks could be cut out for locating antennae) it was coming! EGPWS was being mandated, which required a simplex GPS antenna mount, and GPS updating for the INS was being seriously looked at. In the first case, the EGPWS requires accurate present position to check agaings it's terrain database for known obstacles and the latter case was because the Concorde INS navigational accuracy fell outside of future (now actually) long range navigational accuracy requirements.
Sorry for such a long winded blurb, but I've been away for a while and am gradually looking back over our wonderful thread to see if there is anything I can contribute to/prattle on about.

Agreed and well said, my point was and is that an Inertial source, whatever form that may take is still an invaluable input even these days.


The previous poster had insinuated that a GPS installation in the Concorde would have completely replaced the existing INS fit.


Not that simple.

Humble apologies stilton. (A definate case of RTFQ then). You are quite correct in your comment, inertial position is still the 'prime' source of navigation, in modern aircraft with GPS etc being used to refine this position. GPS can never on it's own replace an INS/IRS, in fact at the moment it's difficult to imagine what ever could. (And after all an aeroplane is not an aeroplane without ATTITUDE :p).

Best Regards
Dude :O

No apology necessary whatsoever, you brought a more accurate and refined aspect to the conversation.


Despite the advent of GPS , in my humble opinion having three independent inertial sources on board that function perfectly well without any updating from any source is invaluable.

Sir James Hamilton obit
 

Saw the obituary for Sir James Hamilton with heavy emphasis on the design of Concorde's wing, thought others here might be interested:
Sir James Hamilton - Telegraph

Did Roy Chadwick really contribute to delta wing design? I though Kutchmann and his team did most of the ground work developing the basic delta (as fitted to Chadwick's Vulcan) into the thin narrow delta with vortex lift.

Well AFAIK, the basic delta concept was devised by Lippisch in Germany, and developed there during WWII.
It would be true to say that Chadwick was one of the first outside Germany to use it, but that was essentially with a rounded leading edge, which is a very different animal from the slender delta with a sharp leading edges to deliberately produce strong vortices which give non-linear lift at high AoA.
That concept was definitely the brainchild of Kuchemann and his team (mostly fellow Germans :D) at RAE Farnborough.

Engine rating modes
 

Welcome everyone. I am new to this forum and thread but must confess that I have read all the pages of this amazing topic. I am an aviation enthusiast flying on different planes in FS9. One of them is SSTSIM Concorde. My question concerns engine rating modes in general with Concorde in mind.

AFAIK (and this is a perfect time and place to fix my knowledge) engine rating modes on ordinary turbofan engine are:

- TO- dictated by safety - full power in order to get obstacle clearence/ GA
- CLB - cut down in power for engine prolonged life, but still high to get to fuel efficient altitude ASAP
- CRS - for economic and long, stable flight

Concorde is not an airplane, so things look quite different, huh?;)
We have a pair of switches, one is take off - flight, second climb- cruise, so we have:

1. Take off with TO and CLB
2. Climb with FLT and CLB
3. Cruise with FLT and CRS
4. Descent with FLT and CLB
5. Approach with TO and CLB

Can somebody explain, what really engine rating modes change in the work of the engine, why we have CLB again for descent (when they work close to idle) and why there are two systems overlapping?
I don't need strict numbers, just general idea confronted with ordinary planes. Thank you in advance.

Dan

Main gear stresses
 

I just watched a video of Concorde turning onto a runway prior to takeoff. The turn was sufficiently sharp for the aircraft to be virtually rotating around the main gear. This is the equivalent of a vehicle the size of a small truck being dragged around in a circle whilst at the same time carrying a load of around 90 tonnes. Howcome it didn't screw the main gear straight out of the wing?

As others have done before, I'd like to add my thanks to the many contributors who continue to make this such an engrossing thread :)

As I look to my left, on the wall is a framed, fading, roughly A2 photo of three of these fabulous aircraft, outside the hanger at Filton in the mid-seventies - presented to my grandfather, who worked there on Concorde production. When I was about ten years old, I was lucky enough to be taken by him on a tour of the works, and can remember being allowed to have a good look around the inside of the aeroplane.

The photo that hangs next to it was taken a few years ago by my bestest flying buddy, Alex, as we thermalled out together over the Brecon Beacons, sitting in bucket seats, suspended, by looms of kevlar, from large, sailcloth kites...

Not too difficult to see where my own inspiration for flying came from :)