** The Climate Change Thread **

[the snail]

Which "Paris air show disaster" was that?

Thanks

Jonathan

Well spotted and you are correct. The disaster happened on a scheduled flight from Paris as referenced a little above.

On 25 July 2000, Air France Flight 4590 crashed shortly after take-off with all 109 occupants and four on the ground killed.

Concorde was dead as an airliner years before that,iirc it was mostly charter flights. As above, people want cheap more than fast - hence the commercial success of the jumbo jet etc. Concorde was too small and too fuel hungry,only wealthy people could afford it. I think the oil crisis in the 70s really killed any chance of commercial viability.

[al_yrpal]

The French dropped Concorde flights before the British. When BA or whatever it was packed it in, that was it apart from short joyrides for a bit.

The clever bit was the variable geometry intakes... Shock on lip air compressors. Concordski never had that thus unviable shorter range.

Al

[Carlton green]

On 25 July 2000, Air France Flight 4590 crashed shortly after take-off with all 109 occupants and four on the ground killed.

Concorde was dead as an airliner years before that,iirc it was mostly charter flights. As above, people want cheap more than fast - hence the commercial success of the jumbo jet etc. Concorde was too small and too fuel hungry,only wealthy people could afford it. I think the oil crisis in the 70s really killed any chance of commercial viability.

The late 70’s certainly saw the price of oil being heigh. I think it would be fair to say that only wealthy people could afford to use Concorde.

People might want cheap more than fast but how many people do you see driving at 55 - 60 mph on the motorway or opting to take a slower and cheaper train over an express service? People want the fastest that they can reasonably afford. It’d be free (with my OAP pass) for me to catch a bus into my nearest city but I always drive because it’s so much quicker (I’d consider cycling but the route available is too likely to see me injured on it).

Back to flying, the speeds of aircraft are a function of the sum of operating costs and airplanes could be more fuel efficient but at the expense of longer journey times - the punter won’t voluntarily accept noticeably longer journey times …

It’s about 3500 miles across the Atlantic so that could potentially be an eleven hour (50% longer) flight in a Turbo Prop aircraft whereas about seven hours might be expected of a Jet - those are rough estimates and initial figures. Then onto that flight time the time spent in airports needs to be added.

Turboprops have an optimum speed below 460 miles per hour (740 km/h).[18] This is less than jets used by major airlines today, however propeller planes are much more efficient.

By increasing efficiency, a lower cruise-speed augments the range and reduces the environmental impact of aviation. According to a research project completed in 2024 and focusing on short to medium range passenger aircraft, design for subsonic instead of transonic speed (about 15% less speed) with turboprop instead of turbofan propulsion would save 21% of fuel compared to an aircraft of conventional design speed and similar characteristics in terms of size, range and expected general technology improvements.

Another analysis from 2014 compared the Airbus 320 from 2009 with a hypothetical turboprop successor flying at a 33% lower Mach number, concluding that the slower aircraft would have 36% less fuel consumption. Both state that the decrease of fuel costs enabled by lower design speed would overcompensate the increase of time-related costs resp. the decrease in revenue passenger miles flown per day. In other words, subsonic turboprop aircraft would be more profitable than transonic turbofan aircraft even at current energy prices without additional costs related to climate action like emission fees, aviation fuel taxation or higher prices for sustainable aviation fuels compared to fossile kerosene.

https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft

What’s the availability of Turboprop aircraft? There is limited availability and certainly nothing of large size thought there certainly could be. Might the future bring more fuel efficient aircraft? I’d have thought that it would but only if there are nonnegotiable fuel efficiency targets on new build aircraft and - without giving suppliers undue advantage - in also retrofitting existing aircraft to be more fuel efficient. Operators will just pay fuel costs and pass them onto their customers.

[al_yrpal]

When we were testing the Concorde airframe in the new Structures building at the RAE we simulated flights. On take off there was tbe huge fuel load and this was applied by weights and rams. At Mach 2 there was kinetic heating of the skin and this was simulated by incandescent heaters. Aluminium can 'creep' at temperatures approaching 200 degrees C and so fuel was pumped around to limit the temperature rise, used as a heat sink. The forces that occurred during takeoff and landing were applied by rams as was the lifting forces on the wings. Thus in the testing period Concordes whole airframe was subjected to repeated whole aircraft load and heating life cycles. Weaknesses and fatigue spots were identified and redesigned out. All this in the place (RAE) where the square window Comet weak spots were identified after testing in a water tank.

The Olympus 593 engines with reheat had been well tested not only in ground level and high altitude test cells at NGTE but in our fleet of Vulcan bombers. At Bristol Siddely the engine was tested with its throttle computer. In tbe adjacent cell we tested the Olympus RX which was the engine used in the TSR2.

When Healey scrapped that under pressure from the Americans I left the aircraft industry which I believed.was doomed. It was great fun at the time....

Al

[Carlton green]

The Yanks, what can one say? The British are a nation led by Donkeys and humbled over time. Once we had great engineering and industry and now we are both a shadow of our former selves and a very divided society. R and D in Aircraft must have been a most interesting line of work, if one that makes one all too aware of how complex aircraft are.

I wonder what the future of flight will be. Battery powered aircraft will use propellers so that’ll be a massive change back into the past. First though better batteries are needed, and that’s away in the future. It’ll be into the long grass with it and decades before (commercial) aircraft cease using fossil fuels.

Fancy a hop across the pond? Aeroplanes were smaller in the past (usually a bit under 100 seats, so say 30% less than a Concorde - both were the super fast vehicles of luxury travel of their day) but it could be and was done by propellor ‘driven’ aircraft with piston engines. https://simpleflying.com/pre-jet-age-main-aircraft/
https://en.wikipedia.org/wiki/Propliner
http://www.propliner.co.uk/
https://en.wikipedia.org/wiki/Douglas_DC-7

[roubaixtuesday]

I've posted a few times about the tipping point on renewable energy costs that seems evident now.

Now in "Science" magazine: The seemingly unstoppable growth of renewable energy is Science’s 2025 Breakthrough of the Year

https://www.science.org/content/article ... rough-2025

[Snoopy]

Re RAF Vulcans I will never forget seeing and hearing 4 take off on exercise whilst I was on duty at RAF Scampton. The whole base seemed to vibrate. A truly beautifully designed Aircraft. Conceived at the end of WW2 at a time when our engineers were the very best.
Concorde designed with a slide rule and early wind tunnels .
TSR 2 Binned although some of the lessons learnt went into Concorde .

[roubaixtuesday]

Looking increasing likely, though not yet certain, that China's emissions have peaked.

https://www.carbonbrief.org/analysis-ch ... 21-months/

[Morzedec]

As Spring approaches, thoughts of many will be turning towards riding yet another End to End, whilst they are still able to so do.

Inevitably, this increases the pasty intake down here in Cornwall, which by extrapolation is bound to increase both forward thrust and Global Warming.

You have been warned.

[al_yrpal]

TSR 2 Binned although some of the lessons learnt went into Concorde .

At Bristol Siddely we tested the Olympus 593 and the Olympus RX in adjacent cells at Gypsy Patch. We had an early computer attached to the throttle to prevent surging.

TSR2 got binned because of jealous actions of the yanks. We usually used slide rules back then but I wrote my first computer program for the Mercury Computer in the RAE in 1966 and I suspect it was used in Airframe and Engine Design.

Al