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Revelation wrote:Aesma wrote:Heinkel wrote:Boom is far, far away from having a "prototype" flying soon. Correct me, if I'm worng, but what I understand is, that they are building a scaled down (1/3 scale?) experimental demonstrator. That is far, far away from what we usually call a "prototype". It is a flyable scale model, same what is known as a "concept car" in the automotive industry.
Technology testbed I would say.
Technology testbed is a good start, but this one doesn't even have the same engine tech needed by the final product.
I'd go with proof of concept, since the only thing it would prove is the concept itself, not the actual tech to be used by the product.
Prost wrote:When Concorde was first in the market the citizenry of the world had to work to get their government’s to pay attention to their environmental concerns. In this decade environmental concerns are at the forefront of governments and a lot of consumers.
I just can’t see a lot of jurisdictions saying ‘ok’ to the occasional sonic boom.
SEPilot wrote:The physics of supersonic flight haven’t changed. And the physics dictate the economics. At the end it cost around $12,000 for a round trip fare crossing the Atlantic on Concorde, as opposed to maybe $3,000 first class. And the end result was that both BA and AF were unable to find enough paying customers to sustain service, which is what killed it. Yes, there are always people able and willing to pay whatever it costs to get there faster, but whether or not there are enough to make it economically viable is the question. And remember, the planes themselves were given to AF and BA for free, with all development and manufacturing costs paid for by the British and French governments. That will definitely not be the case here. I have serious doubts that this venture will survive serious economic examination..
Revelation wrote:Prost wrote:When Concorde was first in the market the citizenry of the world had to work to get their government’s to pay attention to their environmental concerns. In this decade environmental concerns are at the forefront of governments and a lot of consumers.
I just can’t see a lot of jurisdictions saying ‘ok’ to the occasional sonic boom.
This isn't about sonic boom, as above the Boom CEO said they are not trying to solve that problem, they will not go supersonic over land.
It's more about the fact they have to burn a lot more fuel per seat to go supersonic, something that will never change.
MIflyer12 wrote:One can't have 4x fuel burn per seat mile, comparable floor space, small fleet operating economics, and charge comparable prices to 787 J today. That just doesn't work. CRJ-200 seating for J prices? Not for me.
Revelation wrote:Prost wrote:When Concorde was first in the market the citizenry of the world had to work to get their government’s to pay attention to their environmental concerns. In this decade environmental concerns are at the forefront of governments and a lot of consumers.
I just can’t see a lot of jurisdictions saying ‘ok’ to the occasional sonic boom.
This isn't about sonic boom, as above the Boom CEO said they are not trying to solve that problem, they will not go supersonic over land.
It's more about the fact they have to burn a lot more fuel per seat to go supersonic, something that will never change.
Nomadd wrote:MIflyer12 wrote:One can't have 4x fuel burn per seat mile, comparable floor space, small fleet operating economics, and charge comparable prices to 787 J today. That just doesn't work. CRJ-200 seating for J prices? Not for me.
It wouldn't be 4x the fuel burn per seat mile. It would be 4x the fuel burn, but only for half as long, so 2x per seat mile.
gwrudolph wrote:Revelation wrote:Prost wrote:When Concorde was first in the market the citizenry of the world had to work to get their government’s to pay attention to their environmental concerns. In this decade environmental concerns are at the forefront of governments and a lot of consumers.
I just can’t see a lot of jurisdictions saying ‘ok’ to the occasional sonic boom.
This isn't about sonic boom, as above the Boom CEO said they are not trying to solve that problem, they will not go supersonic over land.
It's more about the fact they have to burn a lot more fuel per seat to go supersonic, something that will never change.
I always thought (perhaps incorrectly) based on what I have read that Concorde was most inefficient at subsonic and wasn’t too bad at supersonic cruise?
Nomadd wrote:MIflyer12 wrote:One can't have 4x fuel burn per seat mile, comparable floor space, small fleet operating economics, and charge comparable prices to 787 J today. That just doesn't work. CRJ-200 seating for J prices? Not for me.
It wouldn't be 4x the fuel burn per seat mile. It would be 4x the fuel burn, but only for half as long, so 2x per seat mile.
gwrudolph wrote:Revelation wrote:Prost wrote:When Concorde was first in the market the citizenry of the world had to work to get their government’s to pay attention to their environmental concerns. In this decade environmental concerns are at the forefront of governments and a lot of consumers.
I just can’t see a lot of jurisdictions saying ‘ok’ to the occasional sonic boom.
This isn't about sonic boom, as above the Boom CEO said they are not trying to solve that problem, they will not go supersonic over land.
It's more about the fact they have to burn a lot more fuel per seat to go supersonic, something that will never change.
I always thought (perhaps incorrectly) based on what I have read that Concorde was most inefficient at subsonic and wasn’t too bad at supersonic cruise?
Heinkel wrote:Generally you can say, double speed means 4 x fuel consumption.
v (speed) comes as v². So double speed needs four time the power and the fuel, four times the speed needs 16 times the power and the fuel.
This is simple general physics. When it comes to speeds around the "sound barrier" things become more complicated but in each case the higher speed comes with a huge premium on fuel consumption. At least, as long as you are flying in the atmosphere.
GDB wrote:Ziyulu wrote:Regarding noise, does anyone remember if the Concorde had louder noise during take off and landing as compared to other aircraft?
With the passage of time since 2003, easy to forget or really, not be around to remember it.
Put it this way, if you lived on the flightpath, you knew when it was taking off, which if you were involved in the operation but not on shift, if you did not hear it when expected you wondered about a delay. The head of Concorde Engineering for much of my time there and probably one of the smartest people I have ever met, certainly was not above ringing in to ask 'where is it then?'
Revelation wrote:This isn't about sonic boom, as above the Boom CEO said they are not trying to solve that problem, they will not go supersonic over land.
It's more about the fact they have to burn a lot more fuel per seat to go supersonic, something that will never change.
Lingon wrote:Concorde flew at a higher altitude with lower air density, I guess the Boom aircraft is planned to do so too. So if you fly at double the speed at higher altitude compared to an subsonic aircraft at lower altitude it won't be a factor four for the drag.
A Concorde uses, during the course of a typical trans-Atlantic flight, about 5650 gallons of kerosene every hour. This translates to about 6 gallons of fuel per mile flown. A Boeing 747 consumes about 5 gallons of jet fuel per mile flown.
While this difference seems very small, remember that the Concorde can only carry a maximum of 100 passengers, whereas the 747 is typically configured to carry about 400 passengers. In terms of fuel use per passenger carried, one gallon of fuel on Concorde will take one passenger 16.7 miles, but on a 747 one passenger can travel 80 miles. The 747 is 4.8 times more fuel efficient than a Concorde (and more fuel efficient than two people sharing a private car, too!).
airbazar wrote:The fact that their top speed is Mach 1.7 vs. Concorde's Mach 2 might alleviate some of that.
Also in regards to take-off noise, slow speeds and new wing design might also mean, no afterburner needed at take-off?
Heinkel wrote:Nomadd wrote:MIflyer12 wrote:One can't have 4x fuel burn per seat mile, comparable floor space, small fleet operating economics, and charge comparable prices to 787 J today. That just doesn't work. CRJ-200 seating for J prices? Not for me.
It wouldn't be 4x the fuel burn per seat mile. It would be 4x the fuel burn, but only for half as long, so 2x per seat mile.
Generally you can say, double speed means 4 x fuel consumption.
v (speed) comes as v². So double speed needs four time the power and the fuel, four times the speed needs 16 times the power and the fuel.
This is simple general physics. When it comes to speeds around the "sound barrier" things become more complicated but in each case the higher speed comes with a huge premium on fuel consumption. At least, as long as you are flying in the atmosphere.
Nomadd wrote:Heinkel wrote:Nomadd wrote:It wouldn't be 4x the fuel burn per seat mile. It would be 4x the fuel burn, but only for half as long, so 2x per seat mile.
Generally you can say, double speed means 4 x fuel consumption.
v (speed) comes as v². So double speed needs four time the power and the fuel, four times the speed needs 16 times the power and the fuel.
This is simple general physics. When it comes to speeds around the "sound barrier" things become more complicated but in each case the higher speed comes with a huge premium on fuel consumption. At least, as long as you are flying in the atmosphere.
And, "Per seat mile" is simple English. It's not four times the fuel consumption per trip, but per hour. You're only burning 4 times the fuel for half as long.
And Concorde has nothing to do with it. It had horrible fuel consumption compared to a modern to what a modern M1.7 craft of the same capacity would have.
Nomadd wrote:And Concorde has nothing to do with it. It had horrible fuel consumption compared to a modern to what a modern M1.7 craft of the same capacity would have.
GDB wrote:At take off and during subsonic flight, 82% of the thrust is developed by the engine alone with 6% from the nozzles and 21% from the intake
Revelation wrote:
Concorde piggy-backed off military technology, Boom's main and perhaps only hope is the US DoD becoming interested in helping them develop their project and thus their engine.
It's pretty clear that by the time any Boom could be in service the next generation of subsonic jet engines should be ready for market shortly thereafter, so they will be aiming at a moving target.
airbazar wrote:GDB wrote:Ziyulu wrote:Regarding noise, does anyone remember if the Concorde had louder noise during take off and landing as compared to other aircraft?
With the passage of time since 2003, easy to forget or really, not be around to remember it.
Put it this way, if you lived on the flightpath, you knew when it was taking off, which if you were involved in the operation but not on shift, if you did not hear it when expected you wondered about a delay. The head of Concorde Engineering for much of my time there and probably one of the smartest people I have ever met, certainly was not above ringing in to ask 'where is it then?'
My only "encounter" with Concorde was some time in the 90's, I was sitting in Terminal 3 at JFK waiting for my DL flight to Boston and all of a sudden I hear this loud roar and everything in the terminal starts vibrating. I stand up and run to the windows just in time to watch it take off.Revelation wrote:This isn't about sonic boom, as above the Boom CEO said they are not trying to solve that problem, they will not go supersonic over land.
It's more about the fact they have to burn a lot more fuel per seat to go supersonic, something that will never change.
The fact that their top speed is Mach 1.7 vs. Concorde's Mach 2 might alleviate some of that.
Also in regards to take-off noise, slow speeds and new wing design might also mean, no afterburner needed at take-off?
cpd wrote:Revelation wrote:Concorde piggy-backed off military technology, Boom's main and perhaps only hope is the US DoD becoming interested in helping them develop their project and thus their engine.
It's pretty clear that by the time any Boom could be in service the next generation of subsonic jet engines should be ready for market shortly thereafter, so they will be aiming at a moving target.
Maybe I missed the supersonic military transport or bomber that they converted to become Concorde? Which one was that?
Concorde is an ogival delta winged aircraft with four Olympus engines based on those employed in the RAF's Avro Vulcan strategic bomber.
Revelation wrote:Clearly Boom needs to find an engine partner that is willing to commit to the cost, time to market, emissions, thrust, fuel burn, durability and noise parameters they need to make the Overture project viable.
Revelation wrote:cpd wrote:Revelation wrote:Concorde piggy-backed off military technology, Boom's main and perhaps only hope is the US DoD becoming interested in helping them develop their project and thus their engine.
It's pretty clear that by the time any Boom could be in service the next generation of subsonic jet engines should be ready for market shortly thereafter, so they will be aiming at a moving target.
Maybe I missed the supersonic military transport or bomber that they converted to become Concorde? Which one was that?
Wiki sez:Concorde is an ogival delta winged aircraft with four Olympus engines based on those employed in the RAF's Avro Vulcan strategic bomber.
Ref: https://en.wikipedia.org/wiki/Concorde
I thought the context was clear, I was taking about engines.
Maybe you could have included the previous sentence:Revelation wrote:Clearly Boom needs to find an engine partner that is willing to commit to the cost, time to market, emissions, thrust, fuel burn, durability and noise parameters they need to make the Overture project viable.
Hope it is clear now.
Aerion’s decision May 21 to close up shop and cease development of a small SST that would have competed with Boom is sad news. This was the most realistic concept of the three small SST business cases.
At various points, Lockheed Martin, Airbus, Boeing and Spirit Aerosystems were key investors and R&D partners. The first three withdrew for various reasons and Spirit, at least publicly, hung in until the end. GE/CFM was working on the engine.
If Aerion with all this credibility couldn’t make a go of it, what does this say about the two other programs?
cpd wrote:I'm going to take a risk and suggest there are huge differences between the Vulcan engines and the Concorde engines.
If only it was just so easy as borrowing the Vulcan engines and away you go.
The Rolls-Royce Olympus (originally the Bristol B.E.10 Olympus) was the world's second two-spool axial-flow turbojet aircraft engine design, first run in May, 1950 and preceded only by the Pratt and Whitney J57, first-run in January, 1950.[1][2] dating from November 1946,[3][4] although not the first to run or enter service. It was originally developed and produced by Bristol Aero Engines. First running in 1950,[5] its initial use was as the powerplant of the Avro Vulcan V bomber. The design was further developed for supersonic performance as part of the BAC TSR-2 programme. Later it saw production as the Rolls-Royce/Snecma Olympus 593, the powerplant for Concorde SST.
kyu wrote:GDB wrote:At take off and during subsonic flight, 82% of the thrust is developed by the engine alone with 6% from the nozzles and 21% from the intake
I used those very figures in a lecture, until a student noticed that they do not add up to 100%.
Revelation wrote:cpd wrote:Revelation wrote:Concorde piggy-backed off military technology, Boom's main and perhaps only hope is the US DoD becoming interested in helping them develop their project and thus their engine.
It's pretty clear that by the time any Boom could be in service the next generation of subsonic jet engines should be ready for market shortly thereafter, so they will be aiming at a moving target.
Maybe I missed the supersonic military transport or bomber that they converted to become Concorde? Which one was that?
Wiki sez:Concorde is an ogival delta winged aircraft with four Olympus engines based on those employed in the RAF's Avro Vulcan strategic bomber.
Ref: https://en.wikipedia.org/wiki/Concorde
I thought the context was clear, I was taking about engines.
Maybe you could have included the previous sentence:Revelation wrote:Clearly Boom needs to find an engine partner that is willing to commit to the cost, time to market, emissions, thrust, fuel burn, durability and noise parameters they need to make the Overture project viable.
Hope it is clear now.
FluidFlow wrote:The other was that the engines had to be optimised for a specific operating range and obviously it was cruise speed, but that came at a huge cost, because during take off and climb the engines were burning fuel like mad.
mxaxai wrote:The same affects wings; an efficient subsonic or transonic wing looks very different from an efficient supersonic wing. Concorde's delta planform is a compromise that combines decent supersonic performance with a low stall speed, albeit at the cost of high subsonic drag.
mxaxai wrote:FluidFlow wrote:The other was that the engines had to be optimised for a specific operating range and obviously it was cruise speed, but that came at a huge cost, because during take off and climb the engines were burning fuel like mad.
That affects all aircraft. For each operating altitude and speed, there's some optimum engine configuration. The faster you go, the lower the optimum bypass ratio. Any subsonic engine, however, works well across a wide range of conditions (usually the BPR is chosen slightly higher than ideal to reduce takeoff noise at the cost of a slight increase in fuel burn). But, as you pass Mach 1, a high BPR simply adds tons of drag.
Hence, a very low bypass ratio is actually the most efficient for supersonic flight. Consider the F135, for example, with a BPR of 0.57 : 1, or the EJ200 with 0.4 : 1. The issue with this is that you are - obviously - subsonic during takeoff and climb and have to make do with a very suboptimal engine.
btfarrwm wrote:With a trijet design, could the tail-mounted engine be a higher-bypass model optimized for efficient/quiet subsonic flight? The wing-mounted engines could then be optimized for added power during takeoff/climb and supersonic cruise. The tail ducting could be designed in a way that diverts airflow above Mach 1 and thus reduce drag. It would add complexity for sure, but it may be a way to achieve some of Boom's lofty goals without having three engines that sacrifice efficiency during all phases of flight.
Revelation wrote:The article goes on to point out how when it was written this difference in fuel consumption didn't matter because BA was able to charge a such a premium for Concorde service that the cost of fuel was easy to bear.
What's different now is Boom is saying they won't need such a premium, which IMO is marketing tripe. It may not be needed, but if it is available it surely will be taken, because airlines exist to make money. And now we care more about the environmental impact of flying so few passengers while burning so much fuel.
mxaxai wrote:Something along those lines is the idea that led to the variable cycle engine: https://en.wikipedia.org/wiki/Variable_cycle_engine
GE recently built a prototype, the XA-100. However, it remains to be seen just how large the benefit of such engines is. The USAF has been funding the research that led to this prototype for nearly 15 years. https://www.aerospacetestinginternation ... ngine.html
iamlucky13 wrote:Instead, Boom is expecting engine manufacturers will pitch derivatives of existing designs to keep development costs modest. The most obvious difference will be lower bypass ratios. In fact, the GE Affinity that they were planning to develop for Aerion before shutting down was based on the CFM56 core. It appears they were very interested in keeping development cost low and reliability high, rather than optimizing for efficiency.
The high-pressure core is derived from the nine-stage compressor and single-stage turbine of the CFM56, matched to a new low-pressure section optimised for supersonic speed with a 133 cm (52in) diameter fan instead of the 155-173 cm (61-68.3in) fan of the 6:1 bypass ratio CFM56.[5] The twin-shaft, twin-fan engine with FADEC has a service ceiling of 18,300 m (60,000 ft). It lacks an afterburner, and has a combustor with advanced coatings and uses additive manufacturing technologies.[2]
The 18,000 lbf (80 kN) GE Affinity has a nine-stage HP compressor, a single-stage HP turbine and a two-stage low-pressure turbine. Preceded by fixed inlet guide vanes with movable flaps, the twin blisk fans have wide-chord titanium blades. The exhaust mixer is similar to the GE Passport ceramic matrix composite design.[10] The Mach 1.4-to-1.6 speed requires no variable-geometry inlet and the variable-area nozzle has a cone moving longitudinally, replacing a convergent-divergent nozzle.[11] The bypass ratio is around 3 to lower the ram drag, and it should produce 3,500 lbf (16 kN) at Mach 1.4 and FL500, with a cruise fuel consumption increased by 50% over the Mach 0.78 CFM56-5.[12]
Launched in May 2017 to power the Aerion AS2 supersonic business jet, its initial design was completed in 2018 before its detailed design in 2020 for the first prototype production. GE Aviation discontinued development of the engine in May 2021.
Revelation wrote:So even starting with the existing high pressure parts, they were still in detailed design four years after launch with no prototypes yet constructed. Suggests to me it'd probably be at least an eight year overall time line to finish detailed design, get a prototype built, get some flight testing for it, make production representative engines, then get them through certification. Hard to see how Boom can make a 2029 EIS without a committed engine partner at this point in time.
GDB wrote:To answer posts 420 and 429;
We never got to see how the GE4 would have performed in flight, however it had a shock cone design for the intake control, similar to the SR-71. Though the eventual Mach 3 FAA requirement for a US SST was dropped to Mach 2.7, might have influenced that design decision.
However, I understand that it was not unusual for this system to cause surges in flight, not what you want for a civil airliner. Had it been built, I suspect the 2707's flight testing would have been if not quite as long but certainly as challenging as Concorde.
The intake design on Concorde had it's own long development, change to digital controls when the technology was there, from 1972. In service the testing of them was a quite major thing, luckily we had a couple of 'gurus' involved from the start, in one case in their development at BAC.
Fluidflow, the early design decision on Concorde to be Mach 2, allowed use of conventional materials, still viable at Mach 2, it was an aluminium alloy RR58, which contained small amounts of copper to aid in the expansion.
Expansion joints were fitted and both hyd. fluid and sealants were developed specifically for Concorde.
Like the SR-71 on the ground, you would see fluids under the aircraft, though not to anything like the same extent.
They were monitored, there were limits, going over them would mean an input to fix them.
Specific inputs for this were not usual, though the worst was G-BOAE, someone who was there when it was delivered to BA in 1977 told me it was like that from the start!
This reflected the small production run and that as a result, the fleet were essentially hand built. All with their own character!
Of course one positive of the heating at high speed was in corrosion prevention.
JetBuddy wrote:I don't think a single one of these will end up in United. If any of them are certified.
The contract is full of requirements and loopholes, very easy for United to get out of.
The timeline is way too aggressive. 2025 for rollout, 2026 for first flight and 2029 for carrying passengers.
estorilm wrote:JetBuddy wrote:I don't think a single one of these will end up in United. If any of them are certified.
The contract is full of requirements and loopholes, very easy for United to get out of.
The timeline is way too aggressive. 2025 for rollout, 2026 for first flight and 2029 for carrying passengers.
EXACTLY this. ^^^
They will buy them IF their performance, safety, and reliability constraints are met.
In other words, this was just a temporary PR boost for United (and more so Boom.)
Boom reminds me a lot of Blue Origin, and not in a good way. Their "baby boom" is taking far too long for such a small aircraft, and Mach 1.7 is cool and all, but it's certainly not Mach 2 "cool".
It's possible they'll fill the thing with enough executives with deep pockets to actually keep the planes booked, BUT I highly doubt they'll be allowed to fly the routes that such passengers will demand. Even if they do, it'll be hard to squeak out a profit.
Edit: Yup, first flight was supposed to be 2017. For the 17-foot-wide tech demonstrator!
I see this whole thing going the way of the Concorde and every other SST.
BREAKING: United announces that Boom Supersonic planes will take off from that freaking circular runway that some friend who knows you're into aviation shares with you on Facebook every six freaking months.
GDB wrote:estorilm wrote:JetBuddy wrote:I don't think a single one of these will end up in United. If any of them are certified.
The contract is full of requirements and loopholes, very easy for United to get out of.
The timeline is way too aggressive. 2025 for rollout, 2026 for first flight and 2029 for carrying passengers.
EXACTLY this. ^^^
They will buy them IF their performance, safety, and reliability constraints are met.
In other words, this was just a temporary PR boost for United (and more so Boom.)
Boom reminds me a lot of Blue Origin, and not in a good way. Their "baby boom" is taking far too long for such a small aircraft, and Mach 1.7 is cool and all, but it's certainly not Mach 2 "cool".
It's possible they'll fill the thing with enough executives with deep pockets to actually keep the planes booked, BUT I highly doubt they'll be allowed to fly the routes that such passengers will demand. Even if they do, it'll be hard to squeak out a profit.
Edit: Yup, first flight was supposed to be 2017. For the 17-foot-wide tech demonstrator!
I see this whole thing going the way of the Concorde and every other SST.
Except that Concorde did enter service, did carry pax, for over a quarter of a century.
Boom isn't even the B2707, from the biggest planemaker in the world at the time and backed by 95% government funding.
Nor even the TU-144, which flew, was hugely redesigned but did not fly commercial pax at least in the commonly accepted fashion, but only for a very short time.
If designing and building a new, environmentally acceptable SST, large, medium or small, that was also a commercial prospect, why haven't Boeing, nor Airbus, nor for a potential SSBJ, (Biz Jet, not the fastest version of the so called 'mile high club'), one of the major Biz jet makers, none of which seem to have any interest in the idea.
I do have a brochure from Boeing from the 1990's looking at future SST's, that brochure was likely as far as they took it.
So what does Boom have that these companies don't?
estorilm wrote:I guess you're agreeing with me? My point of "the way of every other SST" was that they were never commercially successful, and EU govts dumped insane money into the aircraft and essentially FORCED their airlines to buy it. Also the sonic boom itself became an issue and routes were quickly removed due to intense backlash from homeowners near the routes. I know they've apparently "reduced" the sonic boom, and there will only be one, but this is also 2021. People could shut this whole thing down in no time.
slider wrote:GDB- I've said it before but it bears repeating, thank you!
I've really enjoyed your posts on this subject, given your own rich experience in this arena. Great stuff!!
@IATA chief Willie Walsh on Boom Supersonic: No, I wouldn’t be buying one. I have the nice position of seeing what the profitability of Concorde was. If it had still been flying when I became BA CEO, [grounding it] would have been my first decision
Revelation wrote:Quite a take down by WW:@IATA chief Willie Walsh on Boom Supersonic: No, I wouldn’t be buying one. I have the nice position of seeing what the profitability of Concorde was. If it had still been flying when I became BA CEO, [grounding it] would have been my first decision
Ref: https://twitter.com/MaxK_J/status/1402983597645107212
Undermines a lot of the a.net narratives about Concorde's profitability at BA, IMO.