Quoted post unavailable.
Just months ago weren't they hoping to use someone else's engine? and now already they have this?
Rolls Royce dropped them in September, after a 2 years partnership thing.
Boom takes the wraps off its supersonic Symphony engine design
41–50 of 99 posts
Re: Boom takes the wraps off its supersonic Symphony engine design
#42Earlier quoted context omitted.
A popular turbofan with civilian fighter jets is the TFE731 with 3,500–4,750 lbf [1] and can be fitted to i.e. the L39 Albatross trainer jet. [2] Supersonic jets like the F5 might use something like the GE J85 which produces a base 3,500 lbf or 5,000 with an afterburner [3]. [1] https://en.m.wikipedia.org/wiki/Garrett_TFE731 [2] https://en.m.wikipedia.org/wiki/Aero_L-39_Albatros [3] https://en.m.wikipedia.org/wiki/Ge…
civilian fighter jet ? Is that a US thing ?
Mostly. Ironically the most popular civilian fighter jet is a Soviet era Czech design (the aforementioned L39).
Even in the US though, they are relatively limited in where they can fly and require an experimental aircraft authorization. It’s relatively impractical in most of Europe because they’re not allowed to fly above populated areas except to take off and land (at least in the US)
Re: Boom takes the wraps off its supersonic Symphony engine design
#43Quoted post unavailable.
Interesting you say that, I look at a company like Arrival and think fantasy company, they don't show any of their manufacturing processes, instead doing robot dances. However, boom looks to be taking a modern but practical approach to their manufacturing and have a test plane almost ready to fly. Timelines are aggressive but if contend that wouldn't put it in fantasy land.
Re: Boom takes the wraps off its supersonic Symphony engine design
#44It's very disappointing to see how skeptical HN has become about new technology. Making aircrafts is hard, making supersonic aircraft even harder and making a new supersonic aircraft company hardest of all. That there's progress by Boom should be encouraged. Otherwise we are just saying that aircrafts will continue to be the domain of Airbus and Boeing only who don't have much incentive to innovate.
Where's the new technology though? It's just a turbofan engine. We should be super skeptical these days. Too many promises and not enough deliveries. Also, just because something is hard, doesn't mean it shouldn't deserve criticism.
> Where's the new technology though? It's just a turbofan engine.
A supersonic no-afterburner 35000 lbf mid-bypass (whatever they mean by that) turbofan, cheap enough (to build and maintain) for civil variation, designed in two years would be a pretty impressive thing tho. If it existed. Especially from a company whose biggest previous offering is a 900lbf turbofan.
The F-35's F135 "only" has 28000lbf dry thrust, and the plane tops out at 1.6, while Overture is supposed to reach 1.7 (and supercruise, which the F-35 can not do).
Although in fairness the Tu-144D had engines specced at 54 and (like Concorde) cruised at M2.
On the other hand, it was even less efficient and economically justifiable than Concorde, and the entire thing was shuttered in 1983, after only 6 years, and regular groundings (Tu-144 only flew scheduled 103 times before the programme was cancelled, BA alone flew Concorde near 50000 times, and the class logged more than a million flight hours.)
But here all that exists is a Boom PR release.
Re: Boom takes the wraps off its supersonic Symphony engine design
#45Earlier quoted context omitted.
Interestingly, it's not GE Aviation (the GE division who make engines) but GE Additive, a division of GE who specialise in Additive manufacturing (aka 3D printing) metal parts. So it's going to have 3d printed rotors and probally other , which is super cool. GE Additive have previously made 3d printed turbine parts for GE Aviation[1], so they do have some experience. Also, this appears to be Kratos' second jet engine…
Turbine blades are the bits that whizz around really fast and are subject to extremes of temperature and force. Established engine manufacturers go to interesting lengths to make turbine blades made of interesting materials like single crystal metal alloys just so that they can cope with the conditions. In a jet engine, a small increase in working temperature gives a significant improvement in efficiency and performa…
It doesn’t look like they printed the rotors. It’s hard to find real concrete info but it looks like they added cavities to other parts of the engine for active cooling and/or increased strength to weight, which is more of a well explored topic (I remember watching a rocket engine test in Mojave with a hollow cryocooled aluminum nozzle in the late 2000s).
The rotors are still made using those fancy 5-axis CNCs - I think either Boeing or GE still have a shop in LA that makes them.
Re: Boom takes the wraps off its supersonic Symphony engine design
#46- "And it is built specifically for use with Sustainable Aviation Fuel, a cleaner alternative to ordinary jet fuel — albeit one that costs several times more right now." I've been thinking about this for a while, in the context of multiple different startups. There's this (anti)pattern I see repeatedly: a startup says they're doing something that's an obviously an overwhelmingly bad idea from a business sense, but th…
It says "built specifically for use with", not "only works with". Is there anything that says it cannot work with other sources of fuel, either natively or at least with some adaptation?
I've seen plenty of products whose marketing says "built specifically for use with (our other product)"; that doesn't mean it only works with that.
If you're building something that won't get deployed for a while, you want to take the design constraints into account that you're going to need to work with, not just those valid today. It's not unreasonable, if you think your design will both take a while and need to stay in service for a while to pay off, to include future-proofing.
Re: Boom takes the wraps off its supersonic Symphony engine design
#47[deleted]
Re: Boom takes the wraps off its supersonic Symphony engine design
#48I want to believe but my B.S. detector is pegged at 11 with this company.
That conceptual render is so laughably bad that it reeks of a designer copying a turbine schematic from Wikipedia, but they don’t even know how an axial turbine works or what a stator is. The schematic is similar to a turbine engine in the same way Fred Flintstone’s car resembles a modern automobile. This is looking theranos bad.
I am even wondering if it's an AI-generated picture?
- Look at the top of the last two stages of the "low-pressure compressor", you can see like some "phantom" blade airfoils? And yeah, no stators at all...
- The "high-pressure compressor" is even more bizarre: each stage seems to have a slightly different, random chord length, the first stages' airfoils have alternating pitch/curvature resembling rotor-stator stages but in the last ones they forget about this...
- In the turbine casing they have included some grooves that resemble cooling channels or labyrinth seals but the shapes seem random?
- The primary and secondary dilution air holes in the combustion chamber are huge, like those of small RC gas turbine? No fuel injectors at all?
Re: Boom takes the wraps off its supersonic Symphony engine design
#49"35,000 pounds of thrust" Can anyone compare this to other commercial and military engines?
A bit less than an F-35 engine, a bit more than a single 737 engine.
> A bit less than an F-35 engine
Or quite a bit more for a more equitable comparison, the F135 reaches 43 with afterburners, but it "only" reaches 28 dry.
According to TFA, this fantasy doesn't have afterburners (although the Tu-144D didn't either though, and the RD-36-51 is documented at a pretty incredible 54000 lbf, then again the 144 was not exactly a cheap and efficient plane).
Re: Boom takes the wraps off its supersonic Symphony engine design
#50- "And it is built specifically for use with Sustainable Aviation Fuel, a cleaner alternative to ordinary jet fuel — albeit one that costs several times more right now." I've been thinking about this for a while, in the context of multiple different startups. There's this (anti)pattern I see repeatedly: a startup says they're doing something that's an obviously an overwhelmingly bad idea from a business sense, but th…
Building for SAF is actually one of the plus points I see in this.
It's generally purer than old-fashioned stuff, and the wider industry has already committed to switching to it on all the legacy machines, so there is likely some benefits at the design stage to assuming this better quality fuel is available, which it almost certainly will be.