Author Topic: Boom Aerospace  (Read 68848 times)

Offline john smith 19

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Re: Boom Aerospace
« Reply #20 on: 09/11/2022 09:05 am »
A smaller concord might’ve survived longer than the original concord due to higher flightrate.

That change alone could’ve made a big difference.
Scheduled services don't really work like that. AFAIK all economic analyses reckon Concorde was the smallest economcially viable size for an SST (the French wanted it about 70 as the Caravelle was about that size). Modern thinking is it needs to be in the 200+ and more likely 300 pax size.

Quote from: Robotbeat
But also, global real GDP is more than 4 times what it was in 1969 when Concord debuted. Worldwide airline passenger volume is up like 20 times since 1969.

The original Concord was unchanged in any significant degree from 1969 debut until 2003, an extremely long run. No transatlantic passenger aircraft built in 1969 would be commercially viable today.
Actually there were a number of operational improvements over the years which (gradually) increased range and had other benefits. Some of them were incorporated in the "noise abatement" takeoff process

 Had they got to selling a 17th Concorde they would have done block upgrades and eliminated the after burner entirely, partly with some weight reduction, partly with aerodynamic improvements. There were possible engine upgrades as well, but they would have depended on RR doing them. IOW AB could have been eliminated in the 80s with the technology of the time.

Quote from: Robotbeat
So with upgrading the efficiency to in line with modern standards (obvious differences due to supersonic regime!!!), upgrading avionics and safety and passenger comforts… I can definitely see it doing far better than the original Concord did. The same exact concord but with 20 times the demand for flights debuting in 1969 would’ve made the original Concord a success, with probably lots of follow-on aircraft and upgrades.
Actually Concorde also had range issues. While good enough to get to Paris from NYC it would probably have been more successful if it was sized to get to Frankfurt, which is a very big European trasport hub, as is Schipol.
Quote from: Robotbeat

I think Boom has a chance of success. The wrinkle I think is the fact that making ANY largeish cleansheet passenger jet is incredibly hard nowadays, costing billions in development money, even ignoring subsonic vs supersonic. Propulsion is still a huge questionmark for Overture.

If they can avoid being gobbled up by Boeing or Airbus (or some Chinese firm) while keeping above water financially, it’ll be a huge boon to the stagnant passenger aviation industry (and it’d be interesting to see them branch out to efficient subsonic as well). But let’s not burn that bridge before it hatches or whatever.
Perhaps they should team up with Hermeus, who appear to have an engine but no aircraft  :)
« Last Edit: 09/11/2022 09:26 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline john smith 19

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Re: Boom Aerospace
« Reply #21 on: 09/11/2022 09:24 am »

During the heyday of Concorde, there was a stampede to the bank of payphones in the terminal after deboarding. A lot of the reason why they were paying a premium was to minimize the amount of time they were out of contact with their organizations. Today it's a different world, and with Starlink coming to commercial aviation, the loss of productivity associated with time spent on the airliner is becoming even smaller.
Sat phone calls in flight were availalbe for years and with nano cells on some flights are now available through your mobile. Likewise video conferencing was basically SF when Concorde first flew. With the pandemic people are a lot more used to dealing with people through a monitor.

The real market for this is for people who have to be there in person (or some document they are carrying has to be). Why doens'nt really matter but they cannot be replaced.

[EDIT and yes, that will be charged at a premium.  10x the price compared to standard fare may get you a very nice ride but it won't get you there faster

So what's getting there 2x faster worth? Anyone who thinks they will only charge what a high end fare is will likely be quite surprised. Remember the only way most of us could get this service today would be in the back seat of a military (or former military) combat plane. ]
Quote from: butters
There is a minimum practical size involved, because a delta-winged twinjet isn't going to cut it for transoceanic flights. I was astonished when Boom announced their original plan because it was a twinjet, and with a low aspect supersonic wing, it's not very nice to lose half your thrust over the middle of the Atlantic. They pretty quickly pivoted to a trijet for this reason.
Another issue will be certification. It took a long time for reliability data to build up for regulators to be OK with twin jet aircraft being so far away from a runway. IIRC its one of the reasons Dassult still offer three engine biz jets.
« Last Edit: 09/11/2022 09:49 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline libra

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Re: Boom Aerospace
« Reply #22 on: 09/11/2022 10:16 am »
Concorde Olympus engine was created and funded two major ways
- British side: Vulcan and TSR-2 military legacies
- French side (also  British, make no mistake): government big vanity project, just like Apollo.
- In June 1963 PanAm ordered 6 Concordes, triggering another JFK Apollo moment: the SST mostly forgotten history...

So the engine existed (thanks the British military wallet for that) and then two governments paid for the "polishing" to civilian standards.

Boom can do the same for the first part (borrow an engine from the military, who paid for the development cost) but for the next step... they are not obviously a deep pocket government. Or TWO deep pocket governments. To pay for the engine "polishing" to civilian, FAA / EASA draconian noise and pollution certification process.
That's the big problem I think.

The case and story of Dassault SSBJ (1997-2001) is quite interesting. I often mentions it, not because I'm French but rather because Dassault is a big and experimented player in both fronts - supersonic (for the military) and civilian (Falcon bizjets).
Bottom line: despite 4000 combat jets, 70 years of experience; and 3000 bizjets, 60 years of experience; they ran into a brickwall when looking for an engine. And it sunk the project.
- military turbofans: a good basis, they have the performance and power - but they suck at pollution, noise, fuel SFC, and more annoyingly: the maintenance.
- civilian turbofans are the exact opposite. They have the correct, low maintenance, noise, pollution and SFC levels - but on the speed side, they suck.
- clean sheet design, hybrid of the above two: can be done technically, there is no question about it. "Variable cycle" is the key.
Heck, Concorde B ultimate Olympus (Mk. 625 / 626 last studies, rather than the familiar 610) in 1976 was getting close. Same for the General Electric GE.4 1971-1977 last studies: look at this link. Fascinating.
https://www.airliners.net/forum/viewtopic.php?t=752231
So yes, technically: could have been done right off 1977, 45 years ago.
But financially, big problem for startups like boom: WHO gonna pay ? and this is exactly what is happening to Boom, right now. Rolls Royce reaction is all too typical.

Now make no mistake: I'm not narrow minded, and I would really like to be proven wrong.  But Boom last developments with RR are all too familiar.

Boom design is sexy as hell, and they are bravely trying to tackle the "civilian supersonic aircraft" conundrum from a different direction from the usual (and doomed)
1- "Boeing or Airbus new Concorde"
or
2- "Aerion / Dassault / Sukhoi / Raytheon SSBJ: Super Sonic Business Jet."

Trying that 80-100 passengers slot is pretty daring. Bigger than the SSBJ but a touch smaller than Concorde. Bold and daring. Can't remember from the top of my head any similar concept in recent history.

The closest I can think of is Sud Aviation pre-Concorde "Super Caravelle" and that was 60 years ago - before 1962 !

4500 km range, 80 passengers: Algiers - Paris - Algiers (that was before 1962: the Year of Concorde and also the Evian agreement ceasefire that granted Algeria its independance after 8 years and 100 000 death in  a dirty bush war - but that's another story).


« Last Edit: 09/11/2022 10:20 am by libra »

Offline libra

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Re: Boom Aerospace
« Reply #23 on: 09/11/2022 10:28 am »
Aerion atempts at finding an engine are quite interesting.

At some point they tried tweaking the JT8D. Why ? because of this. https://en.wikipedia.org/wiki/Pratt_%26_Whitney_JT8D

Quote
It was a modification of the Pratt & Whitney J52 turbojet engine which powered the US Navy A-6 Intruder attack aircraft.The Volvo RM8 is an afterburning version that was license-built in Sweden for the Saab 37 Viggen fighter.

I think Aerion hoped the two legacies (part civilian, part supersonic) could be brought together into a decent supersonic & civilian engine. Now that was some smart thinking. And they made a second, similarly clever atempt with the Affinity: this time, from the CFM56.
 Why that one ? same story ! CFM56 core is derived from the F101 of B-1 fame...
https://en.wikipedia.org/wiki/General_Electric_Affinity
https://en.wikipedia.org/wiki/CFM_International_CFM56

JT8D is getting too old and noisy and polluting for present day FAA rules, but CFM56 is not. So maybe Arion was right shifting from the former to the latter, both having similar evolutions and legacies.

Bottom line: Aerion tried twice to use "hybrid" engines, with one foot in the supersonic (military) world, and the other planted on the civilian side.

Well it didn't do Aerion any good, and they went under. But there were many others reasons.

So, at the end of the day most important question might be: can a startup with not-very-deep-pockets pulls out that JT8D or CFM56 "dual legacy" trick ? Getting that Affinity from powerpoint to bench testing and flying ?
« Last Edit: 09/11/2022 10:40 am by libra »

Offline john smith 19

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Re: Boom Aerospace
« Reply #24 on: 09/11/2022 06:00 pm »
Concorde Olympus engine was created and funded two major ways
- British side: Vulcan and TSR-2 military legacies
- French side (also  British, make no mistake): government big vanity project, just like Apollo.
- In June 1963 PanAm ordered 6 Concordes, triggering another JFK Apollo moment: the SST mostly forgotten history...

So the engine existed (thanks the British military wallet for that) and then two governments paid for the "polishing" to civilian standards.

Boom can do the same for the first part (borrow an engine from the military, who paid for the development cost) but for the next step... they are not obviously a deep pocket government. Or TWO deep pocket governments. To pay for the engine "polishing" to civilian, FAA / EASA draconian noise and pollution certification process.
That's the big problem I think.

The case and story of Dassault SSBJ (1997-2001) is quite interesting. I often mentions it, not because I'm French but rather because Dassault is a big and experimented player in both fronts - supersonic (for the military) and civilian (Falcon bizjets).

True.

Keep in mind  a lot of Concorde (like the SR71, which it actually resembles more than many people realize) was in the nacelles holding the engines. While not quite having the number of engine modes the '71 went through getting up to M3 each engine had 13 computers to control each engine/nacelle package (Most would not be what most people would call a computer, being hard wired analog or digital processors to control a specific feature, although at least one was IE a digital processor running a stored program).

The trouble is AFAIK no one builds big pure turbojets anymore (except the russians?). Those that are exist to drive target drones or UAV's

The other issue is that those turbofans use air cooling, where as the J58 didn't, relying just on the high temperature strength of the alloys used.

For this application any engine will be a compromise unless it's a clean-sheet.

The application is at a particullarly difficult point on the difficulty/volume space. Very high performance needed, but not many going to be sold.

In hindsight what Boom need to do is choose an engine and then find someone to mod it to their specific needs. The aircraft equivalent of an automotive engine tuneup place (do such companies exist?)

TBH I thought aerion had a better chance since they could target the high-value corporate travel market. Certification is always going to be tough.

MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Star One

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Re: Boom Aerospace
« Reply #25 on: 09/19/2022 08:14 am »
Seems no one is interested in developing an engine for Boom.

Quote
In the wake of Rolls-Royce’s departure from Boom Supersonic’s Overture programme, three additional propulsion specialists have indicated they have no interest in developing powerplants for supersonic civilian aircraft, leaving fresh questions about who will supply the jet’s engines.

Boom is developing Overture, a four-engined airliner it says will carry 65-80 passengers, fly at Mach 1.7 and have range of 4,250nm (7,871km). First delivery is scheduled for 2029.

However, as yet, there is no engine supplier. That issue was brought into focus last week when Rolls-Royce announced it was exiting the project having completed contracted engineering studies.

Now GE Aviation, Honeywell and Safran Aircraft Engines tell FlightGlobal they also have no interest in developing engines for civil supersonic aircraft.

GE Aviation had been tipped to step in to the Overture programme using a version of the Affinity engine it had been working on to power a supersonic business jet being developed by now-defunct Aerion, a US company that failed in May 2021 amid financial difficulties.

But the engine manufacturer rules itself out: “Civil supersonic is not a segment that we are currently pursuing,” GE Aviation says.

Another of the relatively few companies capable of developing such a powerplant – Pratt & Whitney – declines to comment on the Overture programme. But a top P&W executive stresses that the company remains focused on subsonic engines.

“We haven’t added [civil supersonic] into our overall business strategy,” P&W chief sustainability officer Graham Webb says. He calls supersonic civil aircraft “tangential” to P&W’s core market, and cites efficiency concerns. Indeed, a 2022 report from The International Council on Clean Transportation found that supersonic passenger aircraft would use 7-9 times more fuel per passenger, per kilometre, than subsonic jets burning fossil fuel. ICAO cited the study in its 2022 Environmental Report.

For those reasons, P&W is dumping resources into boosting the efficiency of its geared turbofan. It aims to have an improved powerplant available for the narrowbody jets Airbus and Boeing are expected to field in the mid-2030s, Webb says. “There’s a bit of risk – in terms of distracting your resources, your engineering team – on something that is kind of in a different sector.”

Boom insists Overture will be environmentally sustainable, offsetting its carbon output by burning sustainable aviation fuel (SAF).

“This is the first airplane that is… capable of meeting net-zero carbon,” Boom chief executive Blake Scholl says. “We care deeply about making this not just good for passengers, not just good for airlines, but also good for the planet.”

ICAO’s report calls supersonic jets a “poor use of scarce SAF supplies”, saying their fuel burn largely negates SAF benefits in relation to subsonic jets burning fossil fuel.

Aerospace analysts say few other engine manufacturers could take on the Overture project. “Nobody else can do an engine in this class, realistically, although Honeywell and Safran aren’t inconceivable,” says Richard Aboulafia with AeroDynamic Advisory.

But those companies are also apparently out. “Honeywell has no plans right now to develop a supersonic engine for civilian aircraft,” it says. Honeywell makes turbofans for business jets and Leonardo’s M-346 light-attack/trainer aircraft.

“Supersonic is not part of Safran Aircraft Engines commercial propulsion strategy,” adds the French engine maker.

Safran holds a massive chunk of the civil turbofan market via its CFM International joint venture with GE, which produces Leap engines for Airbus and Boeing narrowbodies.

Safran remains “strongly focused on the RISE initiative to develop the technologies for the next generation of narrowbody aircraft engines,” Safran says.

RISE – Revolutionary Innovation for Sustainable Engines – is a joint Safran-GE effort to develop an open-rotor powerplant, delivering a 20% fuel-burn saving at service entry, likely in the mid-2030s. RISE aligns with a broad push by the aerospace industry to reduce emissions.

Michael Merluzeau, aerospace consultant with AIR, says International Aero Engines (IAE) could “theoretically” have an engine for Boom. A consortium including P&W, MTU Aero Engines and Japanese Aero Engines, IAE makes V2500s, which power aircraft including first-generation A320s and the Embraer C-390.

“That does not, however, mean the engine can be adapted for the Overture [and] can deliver maintenance, fuel burn and performance required, Merluzeau says.

Overture needs “more firm [order] commitments and a firmer industrial roadmap” to attract an engine supplier, he adds. “Without an effective propulsion system, this is a programme that is not going anywhere any time soon.”

R-R on 8 September said it was departing the Boom programme. “After careful consideration, Rolls-Royce has determined that the commercial aviation supersonic market is not currently a priority for us and, therefore, will not pursue further work on the programme at this time,” it said.

In response, Boom said: “It became clear that Rolls’ proposed engine design and legacy business model is not the best option for Overture’s future airline operators or passengers”.

Despite many questions, Scholl insists Overture development is on track, reiterating the company will soon announce an engine partner. He points to order commitments from customers including American Airlines and United Airlines.

“We would not have the customer relationships we have if the airplane that we’re building was not one that the airlines wanted, and so, I think… that speaks for itself,” Scholl says.

In June 2021, United said it had signed a “commercial agreement” – that included a deposit for an undisclosed amount – to buy 15 Overtures contingent on “demanding safety, operating and sustainability requirements”.

Then in August, American said it too had paid a “non-refundable deposit” – it also did not say how much – as part of an agreement to buy up to 20 of the jets.

Boom’s other partners include Safran Landing Systems, Collins Aerospace, fuel-system company Eaton and Northrop Grumman, which is helping with a military variant.

”I feel really good about this – very, very confident we are going to have a great answer. We are looking at multiple offers,” Scholl says.

Story updated on 16 September to note that GE’s engine is called Affinity and that The International Council on Clean Transportation completed the research cited in ICAO’s study.

https://www.flightglobal.com/airframers/engine-makers-sound-downbeat-on-supersonic-leaving-boom-in-a-bind/150215.article

Offline john smith 19

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Re: Boom Aerospace
« Reply #26 on: 09/19/2022 09:15 am »
Seems no one is interested in developing an engine for Boom.

P&W were about the closest they got to maybe consider it will work.

But it's a niche market. It really comes down to 2 options.

1)Go with a military engine with minimal changes and swallow the issues such designs have
2)Go with a civilian engine and wrap it in a nacelle (which you're going to do anyway). Now if they used a precooler on the front of it......

Whatever people say in presentations this task is complex.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Asteroza

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Re: Boom Aerospace
« Reply #27 on: 09/20/2022 01:57 am »
Well, that doesn't really leave many options does it. If they want a US military variant of Overture, then russian engines aren't happening, and no chinese engines either. Who else does that leave?

Offline Star One

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Offline john smith 19

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Re: Boom Aerospace
« Reply #29 on: 09/20/2022 12:24 pm »
Well, that doesn't really leave many options does it. If they want a US military variant of Overture, then russian engines aren't happening, and no chinese engines either. Who else does that leave?
It does make things kind of tough.  :(

The French (but Saffran has said "non" already)?   :(

India? They have a vigerous aircraft industry, are in the West. But on the Wiki list of supersonic aircraft their "Tejas" is engined by a GE 404.

Japan and Israel also build supersonic aircraft, but again their engines seem to be versions of GE engines, nothing home grown. It's not that surprising. LBR turbofans are a niche market. Fuel efficiency is not exactly their strong suite.  :(

And then of course there's the fact that they have raised about $600m (a lot of money by rocket startup standards) but are needing $6-8Bn.

Of course if you have nothing to lose and are a world-class fund raiser there's a little outfit in Abingdon, Oxford that might be worth a call.  ;)
[EDIT Also South Korea and Sweden and Pakistan, but again you have to ask where do the engines come from? Looks like the GE 404 except for South Korea (Honeywell F125) or Pakistan (Klimov RD33). Probably not a viable option]
« Last Edit: 09/20/2022 02:18 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Robotbeat

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Re: Boom Aerospace
« Reply #30 on: 09/20/2022 01:14 pm »
Ukraine…
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline john smith 19

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Re: Boom Aerospace
« Reply #31 on: 09/20/2022 02:56 pm »
Ukraine…
What's left of Antonov is based in the Ukraine, but is merged into a Ukrainian state owned aircraft company.

And IIRC most of its products were transport aircraft, nothing supersonic.

Unless you have someone else in mind?

There appear to be several hang- and para-gliding mfgs based there.
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline Robotbeat

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Re: Boom Aerospace
« Reply #32 on: 09/20/2022 04:50 pm »
They did a bunch of rocket engine work, too. Point is they could make engines for probably an unbeatably cheap price if they weren’t currently being invaded. Aerospace labor costs there are less than a tenth those of the US, IIRC.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline john smith 19

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Re: Boom Aerospace
« Reply #33 on: 09/20/2022 07:21 pm »
They did a bunch of rocket engine work, too. Point is they could make engines for probably an unbeatably cheap price if they weren’t currently being invaded. Aerospace labor costs there are less than a tenth those of the US, IIRC.
I did'nt know they'd done any engine work.

Unfortunately Boom need a jet engine. Ideally a straight turbojet, rather than a Low Bypass Ratio turbofan, which no one seems to make any more in large sizes (like the ones on the XB70 for example).

But I'm betting the best  you can get these days will be a LBR turbofan.  :(
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

Offline edzieba

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Re: Boom Aerospace
« Reply #34 on: 09/20/2022 08:47 pm »
Option 1: Military surplus.
Cons - supply is sporadic and constrained (if you can purchase at all), engines are at or beyond reasonable service life, service is expensive, parts are likely limited or unavailable, limited total number of engines available (but likely beyond actual need), high maintenance load, poor fuel efficiency, noise concerns.
Pros - Engines know to work (or at least, have worked in that application), likely cheap per unit if you can buy them at all, lower R&D cost (adapting airframe design to accommodate engines rather than developing engines from scratch), existing base of trained technicians, likely fastest way to get something flying even if suboptimal in terms of maintenance and efficiency.

Option 2: Modify high bypass engine themselves.
Cons - Large R&D workload and cost, time delay before first flight, no technical experience in that field, shoulder engine maintenance costs internally.
Pros - No contractor telling you 'no'.

Option 3: Develop engine internally.
Cons - Greatest R&D workload and cost, huge delay before first flight, no technical experience in that field, shoulder engine maintenance costs internally.
Pros - Engine tailored to their application. Possibility of lower overall cost than paying contractor to develop a new engine for you (but far higher risk of cost overruns).

2 and 3 offer the possibility of going for an Ammonia-cycle engine, but with even grater R&D cost and risks. However, it has the tantalising possibility of an actually carbon-emission-free engine (completely quashing most complaints over carbon emissions per passenger mile) and usage of inlet air cooling for both Ammonia cracking and performance boost (a'la RF-4X).

Offline Asteroza

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Re: Boom Aerospace
« Reply #35 on: 09/21/2022 01:04 am »
Ukraine…

Motor Sich/Ivchenko-Progress would be who you probably go to, but they seem to be primarily turboshaft/turbofan makers/designers. There is the Ivchenko-Progress AI-222, but that's kinda small. There is the small matter of damage to the Zaporizhzhia airport area, where the facilities are located.

Still, a large foreign investment for engine development in Ukraine would get more mileage per dollar spent compared to many other places, and the Ukrainian government is incentivized to bring projects for domestic design/manufacture jobs to avoid an engineer brain drain.

Offline ZuluLima

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Re: Boom Aerospace
« Reply #36 on: 09/21/2022 07:12 am »
Option 3: Develop engine internally.

Okay, we can stop even mentioning that option right now.  It is impossible, period.  There are only 4 companies on earth that could make this kind of engine, and it would take billions of dollars and many years for them, the experienced, established players with existing designs, infrastructure, workforce, etc to pull it off.  If Rolls freaking Royce can't handle the project, no one who isn't named GE, Pratt & Whitney, or Safran can.  Even the Russians and Chinese are several decades behind, despite vast resources being thrown at engine development in the past half century.  Simply put, jet engines are THE bleeding edge of technology right now.  A program like this makes a methalox rocket engine look like a bicycle.  The metallurgy alone would bankrupt most nations.  Not exaggerating; notice how there are only 3 world-power nations represented on the list above.

I won't even get started on "Possibility of lower overall cost than paying contractor to develop a new engine for you" or "possibility of an actually carbon-emission-free engine" as this is several magnitudes of order beyond fantasy.
« Last Edit: 09/21/2022 07:20 am by ZuluLima »

Offline edzieba

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Re: Boom Aerospace
« Reply #37 on: 09/21/2022 09:03 am »
Similar claims of impossible complexity were made for rocket engines, but reality has proven otherwise.

Boom also do not need the most bleeding-edgiest high-bypass turbofans on the planet, nor do they need an elaborate hypersonic engine. What they need is the state of the art as of the mid 1950s, and their problem is the market has moved away from servicing that need.

RR did not claim they could not make the engine (they've even manufactured engines of the required specifications in the past), they just don't want to shoulder the economic risk of doing so.

Offline Asteroza

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Re: Boom Aerospace
« Reply #38 on: 09/21/2022 09:56 am »
Similar claims of impossible complexity were made for rocket engines, but reality has proven otherwise.

Boom also do not need the most bleeding-edgiest high-bypass turbofans on the planet, nor do they need an elaborate hypersonic engine. What they need is the state of the art as of the mid 1950s, and their problem is the market has moved away from servicing that need.

RR did not claim they could not make the engine (they've even manufactured engines of the required specifications in the past), they just don't want to shoulder the economic risk of doing so.

Would RR be amenable to licensing the design to a Ukrainian maker perhaps? Same for GE?

Offline john smith 19

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Re: Boom Aerospace
« Reply #39 on: 09/21/2022 11:24 am »
Boom also do not need the most bleeding-edgiest high-bypass turbofans on the planet,
High bypass ratio is exactly what the don't need, but is exactly what the market wants to provide, outside military applications.
Quote from: edzieba
What they need is the state of the art as of the mid 1950s, and their problem is the market has moved away from servicing that need.
Unfortunately that won't cut it either. That was good enough for Concorde, back when oil was $3/barrel.

In 2022 that's not going to cut it.  :(

Quote from: edzieba
RR did not claim they could not make the engine (they've even manufactured engines of the required specifications in the past), they just don't want to shoulder the economic risk of doing so.
Whatever Boom's CEO says the existing market for what they are looking for is either miniscule, or non-existent.

I think in-house mfg (directly or through sub-contractors) is not entirely impossible.

What boom need is a turbojet or LBR turbofan. One option reduces the size of features needed (significantly widening the number of possible companies that could help). The other eliminates it as a problem entirely.

Then we get the power turbine blades. SoA blades are inlet air cooled (with elaborate internal channels), ideally cast as single crystals. Very high tech.

OTOH one of the key features of the J58 core was that it had no air cooling. It just relied on keeping the blades cold enough.
In fact a key feature of the J58 used on the SR71 was that most of the "cold" parts were also made out of high temperature alloys, necessitating P&W learning out to make stuff that was traditionally forged in lumps (IE Blades) into sheet or thin sections.
In the 70+ years since Kelly Johnson's team started trying to mfg it metallurgy has moved on a bit.
This suggests the outline of a possible plan.
Choose a more modern alloy with an upper usage temperature may 100-200c higher, preferably not powder metellurgy.
No air cooled blades. No single crystal blades
Used forged disks and machine the blades integrally to the disk (obviously this is a compromise material and puts a forge in your critical path. The alternative is cast, and that puts a foundry in your critical path).
Gas turbine speeds favor small high speed alternators and power electronics. Use electric actuation through long rods for engine and flight controls.

Engine casings have to be strong to contain blade failure. That suggests a forged casing of relatively large diameter (although squeeze casting might be an option). Obviously if it were possible to design to a diameter of an existing casing they could approach the forge house and ask to use some of them as "raw" forgings, bespoked to their internal design. Risky, but potentially quite a money saver. OTOH centrifugal casting can deliver high quality castings at <= 8m in diameter, as the impurities and dross are forced to the center, allowing them to be machined away.

For simplicity "Can" type combustors allow that part of the engine to be developed as small units that are replicated once the design is stable.

It's not got to compete with the other SoA engine mfgs products. It's just got to be good enough to fly the mission. :(

I suspect the real challenge would be getting commercial grade reliability. Airliners have logged engines with 40 000 hrs on the wing, without removal for a major overhaul. I'm not sure what the current standard expectation is, but I'd guess 10 K hrs minimum?

I don't think an in-house engine is completely impossible, but it's very demanding and you can expect the FAA will be all over them for this (in addition to being all over them for the aircraft itself).

What has changed from the 50's is the level of technological leverage available, allowing a sufficiently skilled small team to deliver results that historically needed a much larger team to deliver in the same timeframe.

Time will tell if a new player steps forward (Honeywell?), they bite the bullet and build in-house or if this is the final nail in the coffin.  :(
« Last Edit: 09/21/2022 11:42 am by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022 2027?. T&C apply. Trust nothing. Run your own #s "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap SCramjet proposed 1956. First +ve thrust 2004. US R&D spend to date > $10Bn. #deployed designs. Zero.

 

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