. That was good enough for Concorde, back when oil was $3/barrel.
Quote. That was good enough for Concorde, back when oil was $3/barrel. Not even close. PanAm cancelled their orders in January 1973, not 1974 - that is months BEFORE the first oil shock
Quote from: edzieba on 09/20/2022 08:47 pmOption 3: Develop engine internally.Okay, we can stop even mentioning that option right now. It is impossible, period.
Option 3: Develop engine internally.
This reminds me of when making pumpfed rocket engines was only considered possible for a handful of aerospace primes, now you have everyone and their mom building them. Even amateurs are building turbopumps and some of these small space companies like Ursa Major (and Launcher) are building oxygen-rich staged combustion engines, which literally no US company had done 20 years ago (and was thought practically impossible before the fall of the Iron Curtain).
Quote from: ZuluLima on 09/21/2022 07:12 amQuote from: edzieba on 09/20/2022 08:47 pmOption 3: Develop engine internally.Okay, we can stop even mentioning that option right now. It is impossible, period. I don’t think Boom will do that, and they’d almost certainly go bust if they tried, but that’s poppycock.Jet engines are very complicated, but they are not magical.This reminds me of when making pumpfed rocket engines was only considered possible for a handful of aerospace primes, now you have everyone and their mom building them. Even amateurs are building turbopumps and some of these small space companies like Ursa Major (and Launcher) are building oxygen-rich staged combustion engines, which literally no US company had done 20 years ago (and was thought practically impossible before the fall of the Iron Curtain).An axial flow jet engine is more mechanically complicated than the typical centrifugal turbopump, but the same “impossible for the little guys” mindset that was common 20-30 years ago for pumpfed engines that people have for jet engines today is just as magical-thinking as anything else.It’s not magic, it’s just physics and engineering.People who talk like this demonstrate their own ignorance (on the one hand) or hubris (on the other).
Jet engines are very complicated, but they are not magical.An axial flow jet engine is more mechanically complicated than the typical centrifugal turbopump, but the same “impossible for the little guys” mindset that was common 20-30 years ago for pumpfed engines that people have for jet engines today is just as magical-thinking as anything else.It’s not magic, it’s just physics and engineering.People who talk like this demonstrate their own ignorance (on the one hand) or hubris (on the other).
Quote from: Robotbeat on 09/21/2022 02:15 pmQuote from: ZuluLima on 09/21/2022 07:12 amQuote from: edzieba on 09/20/2022 08:47 pmOption 3: Develop engine internally.Okay, we can stop even mentioning that option right now. It is impossible, period. I don’t think Boom will do that, and they’d almost certainly go bust if they tried, but that’s poppycock.Jet engines are very complicated, but they are not magical.This reminds me of when making pumpfed rocket engines was only considered possible for a handful of aerospace primes, now you have everyone and their mom building them. Even amateurs are building turbopumps and some of these small space companies like Ursa Major (and Launcher) are building oxygen-rich staged combustion engines, which literally no US company had done 20 years ago (and was thought practically impossible before the fall of the Iron Curtain).An axial flow jet engine is more mechanically complicated than the typical centrifugal turbopump, but the same “impossible for the little guys” mindset that was common 20-30 years ago for pumpfed engines that people have for jet engines today is just as magical-thinking as anything else.It’s not magic, it’s just physics and engineering.People who talk like this demonstrate their own ignorance (on the one hand) or hubris (on the other).The biggest difference between the jet and rocket engine industry is that if your jet engine is 10% less efficient than the market leader, nobody will take your calls....
Quote from: Robotbeat on 09/21/2022 02:15 pmJet engines are very complicated, but they are not magical.An axial flow jet engine is more mechanically complicated than the typical centrifugal turbopump, but the same “impossible for the little guys” mindset that was common 20-30 years ago for pumpfed engines that people have for jet engines today is just as magical-thinking as anything else.It’s not magic, it’s just physics and engineering.People who talk like this demonstrate their own ignorance (on the one hand) or hubris (on the other).People who hand-wave away knowledgeable criticisms demonstrate their own ignorance, too. ...
Quote from: Robotbeat on 09/21/2022 02:15 pmJet engines are very complicated, but they are not magical.An axial flow jet engine is more mechanically complicated than the typical centrifugal turbopump, but the same “impossible for the little guys” mindset that was common 20-30 years ago for pumpfed engines that people have for jet engines today is just as magical-thinking as anything else.It’s not magic, it’s just physics and engineering.People who talk like this demonstrate their own ignorance (on the one hand) or hubris (on the other).People who hand-wave away knowledgeable criticisms demonstrate their own ignorance, too. Try to grasp what is being proposed; name ONE current engine that is capable of what Boom needs. Must be:1. Certified as safe for commercial use and for emissions in post-2030 western world.2. Efficient enough to support range requirements (ocean-crossing) and economics of airline industry.3. Capable of supercruise (supersonic without afterburner) at M1.7.4. Capable of all-day flight-cadence at over 99.8% dispatch reliability, roughly the current standard, and high Mean Time Between Overhauls.5. Sized to fit in a smallish nacelle with all fittings.6. MANY more technical and practical issues that suffuse the aviation industry.I'm sure a startup with modest funding and 0 track record can easily design, manufacture, test, certify, deliver, and support such an engine with never-before-seen performance while simultaneously doing the same for the vehicle, which no one else is also even attempting. Because, "it's not magic".
People who hand-wave away knowledgeable criticisms demonstrate their own ignorance, too. Try to grasp what is being proposed; name ONE current engine that is capable of what Boom needs. Must be:1. Certified as safe for commercial use and for emissions in post-2030 western world.2. Efficient enough to support range requirements (ocean-crossing) and economics of airline industry.3. Capable of supercruise (supersonic without afterburner) at M1.7.4. Capable of all-day flight-cadence at over 99.8% dispatch reliability, roughly the current standard, and high Mean Time Between Overhauls.5. Sized to fit in a smallish nacelle with all fittings.6. MANY more technical and practical issues that suffuse the aviation industry.
Balooney. That's true for rocket engines, too. If you have a hydrolox upper stage engine with just 410s vacuum Isp (vs 450-460s), good luck getting anyone to pick up the phone.And if just accepting 90% of their desired efficiency initially was all they'd have to do to get an engine, Boom would be happy to do it.
Really don't care for people who over-fit on the status quo of the existing, stifled ("mature") industry as the only way things can be done trying to speak authoritatively on what a new effort can and cannot "possibly" do for a new kind of aircraft (supersonic passenger jet) not represented at all in the current status quo fleet.
Bottom line: whoever develop that peculiar engine has to find some billion dollars in development costs. Then - who pays for that ? That's the HUUUUGE issue with supersonic civilian, be it SSBJ or SST.
Plus the sonic boom. Flying overwater is a bit restrictive although acceptable.
There seems to be a new, larger issue. Flying supersonic - basic physics - can only be fuel intensive. With the accelerating global warming and the growing anger at commercial aviation, it is perhaps not a good time to fly supersonic, civilian. Aviation already has hard times trying to find a viable kerosene substitute: ammonia, hydrogen, mix of the two (my favorite solution) SAF, batteries... none is a panacea. And this is for subsonic civilian travel.
With 20 000Km going M5
One idea I don't think anyone has considered is to power the compressor with batteries. Someone has acutally built such a jet engine (for a bench test) using an electric motor to drive the compressor. I've literally no idea if the mass numbers work out, but it would ditch all the heavy high temperature turbine section and greatly simplify the hardware.
I would rather go suborbital with a rocket in the tail, rather than hypersonic inside the atmosphere with any scramjet.
A specific impulse of 345 and a prop mass fraction of 0.80 could get 6500 m/s of delta-v,transportation. But we are disgressing away from Boom... (or bust, which I don't wish them: I love their design).
A specific impulse of 345 and a prop mass fraction of 0.80 could get 6500 m/s of delta-v, and with that ballistic range could be 7000 km to 12 000 km - depends whether or not the trajectory is flattened to not hit the lower van Allen belts.
OTOH air breathing gets you Isp of several 1000s, allowing wings, landing gear that can handl full GTOW etc.