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Air-breathing rocket engine set for key tests
- godelmachine 8y agoIts interesting to know that they are finally testing. I remember reading about Reaction Engines back in 2012 (I was in college) and them working in this technology. Back then it was in primordial stages. How does this technology compare with Ramjet technology and X51? https://en.m.wikipedia.org/wiki/Ramjet https://en.m.wikipedia.org/wiki/Ramjet https://en.m.wikipedia.org/wiki/Boeing_X-51_Waverider https://en.m.wikipedia.org/wiki/Boeing_X-51_Waverider
- baybal2 8y agoScramjets minimise compression losses by minimising compression... Sabre minimisies compression losses by instantly cooling incoming hypersonic air stream with their tricky heat exchanger, thus not doing compression. The turbocompressor after the precooler is pretty much a pump.
- igravious 8y agoInteresting, thanks? You seem knowledgeble on the subject, what's your take on the commercial and technical viability of this tech in general and REL's abilities to execute more specifically in the case the tech is viable.
- baybal2 8y agoMy common sense says that tech is not viable, but reality shows otherwise. Thus, I can't tell much about it from my common sense. The company must be staffed by much more competent engineers in their domain than I am. The most tricky parts in my view are the pre-cooler just for the giant mass flow and temperature difference, and the helium/lh2 heat exchanger, but those two seem to been done. O_O
- igravious 8y agoI see what you're saying but innovation in high-speed mass transport is going to take a breakthrough in tech: could be sabre, could be hyperloop, could be superconducting maglev. Despite what your spidey-sense is telling you, maybe this is one of the breakthroughs we need. Having said that I think we should be aiming for low environmental footprint with all our tech from now on given what we know about the damage we're doing. I'd like to see these breakthrough techs compared in terms of environmental costs. My ideal combo would be superconducting maglev high-speed trains coupled with nuclear power to deliver the electricity.
- close04 8y agoFor mass transit high speed only makes sense for longer distances. Most mass transit is relatively short haul where the acceleration/deceleration times (that still provides a comfortable ride) prevent you from saving any time. Over the speed of sound is great if you want to fly half way around the world. But from Paris to London it doesn't really save you much. Unless it becomes cheaper than regular air travel.
- igravious 8y ago> For mass transit high speed only makes sense for longer distances. Most mass transit is relatively short haul where the acceleration/deceleration times (that still provides a comfortable ride) prevent you from saving any time. Probably I just should have said superconducting maglev trains. I guess you're right that they only need to be properly high speed over longer distances. Superconducting maglev would be a win for acceleration/deceleration as well so would benefit short haul. Realistically speaking, inexpensive superconductors would be a total game changer for many fields, not just mass transport. > Over the speed of sound is great if you want to fly half way around the world. But from Paris to London it doesn't really save you much. Unless it becomes cheaper than regular air travel. I kind of feel that in general it'd be better to replace planes with trains, than to replace planes with better or faster planes. Better security-wise. Better for the environment in the long run I believe. I'm totally open to correction though.
- grondilu 8y ago> I remember reading about Reaction Engines back in 2012 I'm not sure but I think I first watched a CGI rendering of Skylon in the early 2000s (back when I was still a student). I've tried to find the video on YouTube to find out its publication date but it appeared more difficult than I expected. Anyone can find the original video I'm talking about? It's definitely not on the official RE Youtube channel anymore.
- bloopernova 8y agoIf you are interested, Kerbal Space Program has mods for ramjets/scramjets, and the air-breathing rockets are part of the base game now. You can build your own Waverider and mess around with all sorts of fun explosions and crashes!
- varjag 8y agoAs a hydrogen engine it is also carbon neutral. That makes it more environment friendly than both the existing jet engines and Musk's methane rocket hopper.
- xbmcuser 8y agoYeah though hydrogen is produced by burning fossil fuels currently. I hope the tech to get hydrogen from the air and water using solar keeps improving and getting cheaper to the point that it becomes the main source of hydrogen. As hydrogen used as a fuel source and as a way to store renewable energy has a huge potential to bring down the world's carbon production.
- Symmetry 8y agoI'm skeptical about hydrogen's use as a form of energy storage but a carbon neutral source of hydrogen for chemical processes, especially the generation of fertilizer, would be a huge deal.
- xbmcuser 8y agoI was talking about this tech. You get solar electricity as well as hydrogen that you can later burn to get electricity at night when no sun. https://www.greencarcongress.com/2019/03/20190308-kul.html https://www.greencarcongress.com/2019/03/20190308-kul.html
- jacobush 8y agoThat comment has very little substance. Where do you get the hydrogen? Where do you get the jet fuel? The answer determines if it's environment friendly.
- deleted 8y ago[deleted]
- igravious 8y agoYes. So-called `green tech' and its boosters have greenwashed a bunch of tech which is far from actually green and clean when you look at the details. I'm unsure whether these people are ignorant or mendacious. Charitably I'm going with the first option with a touch of the ol' ideological blinkers thrown in for good measure. Examples: (a – transport) electric vehicles, hydrogen-powered vehicles – In the first case, how are batteries made? where do the elements come from, what are the environmental costs? what are the human costs? what are the industrial processes? In the second case, to echo your question, great but where does the the hydrogen come from? And what about disposal and recycling? (b – energy production) wind turbines, solar pv panels – Same set of questions: how are they made? What are the social and environmental costs? What's their lifetime? How are they disposed of or recycled? This is a shame because actually greener tech (like nuclear in the case of energy production, and cycling and mass public transport in the case of transport) is overlooked or sidelined to the detriment of the whole planet. Unsurprisingly this childish ignorance will end up hurting us all. This stuff needs to be taught in schools.
- MrBuddyCasino 8y agoHow exciting! Never expected this to come out of the vapourware stage, the technology sounded just too improbable. Sure would be nice to have an ambitious EU counterpart to SpaceX.
- baybal2 8y agoMe too, the working principle sounds too much sci-fi, and require supermaterials for pretty much everything.
- sveme 8y agoEU for another 11 days, unfortunately. But this is not the place for Brexshitting, so I'm just celebrating this regardless of any politics.
- Angostura 8y agoI'd put it at about 70% chance of a delay now.
- theoh 8y agoMaybe I can get away with the observation that this kind of prestigious engineering project has traditionally been a magnet for proud mercantilists. The Science Museum's book about Concorde contains a breathtaking interview with an engineer who is very keen that technological innovations are not shared with the industries of other countries. Very myopic.
- EngineerBetter 8y agoWow. 1,500C to -150C in 1/100th of a second sounds pretty remarkable. Any idea how that's achieved?
- baybal2 8y agoThere was a movie showing their heat exchanger test going around. It is a gas to gas (helium.) And you can pump helium at very high flow rates. Speed of sound in helium is 1000m/s after all.
- NeedMoreTea 8y agoA helium cooling loop, cooled by a nitrogen boiler. More info and pictures: https://www.bbc.co.uk/news/science-environment-20510112 https://www.bbc.co.uk/news/science-environment-20510112 The Rolls engines designed for HOTOL were meant to do the same, by a different method. They were going to use the hydrogen fuel to operate the intake heat exchangers. The engine then burnt hot hydrogen. Any excess was used as reheat injected into the exhaust.
- scotty79 8y agoWhat do they ultimately do with the heat? Or do they just boil of the nitrogen into the atmosphere and need to take a supply of it for the whole trip?
- isostatic 8y agoThe air breathing operates upto mach 5.14 and 28km (which is higher and faster than an SR71). That would be about 5500km/h. The first stage of a falcoln 9 on the recent flight was 6,600kph and 91km high, so not a direct comparison but fairly close. Re-entry heat shields is still going to be a problem if it goes to orbital velocity of 27kkph for something that's reusable.
- baq 8y agomaaaaaybeee it could save enough fuel for a reentry burn?
- ufmace 8y agoNo chance. This is more like maaaaybe single stage to orbit, though it wouldn't have a very big payload.
- delibes 8y agoThe space plane ideas for using a Sabre engine are fairly early stage designs, since the whole engine isn't even a working prototype yet. Of the various designs I've seen via wikipeda, Reaction Engines PR, and on-line forums, it seems that the thermal management proposals are :- * Bigger lighter air frame will do more thermal soak than other spaceplanes (I mean, what else is there apart from Shuttle and X15?) * Retain some fuel to be circulated through airframe during decent, and then used for powered landing * Less intense re-entry profile to avoid sharp heat spike, but at expense of longer thermal load * Avoid going all the way to orbit, using a small final booster for orbital insertion If they can harvest enough LOx/air in the final ascent, then they could also do a retro burn I suppose. Perhaps a mix of all these, plus heat shields. SpaceX are learning how to deal with similar issues right now too.
- coolspot 8y ago> what else is there apart from Shuttle and X15? Buran, X-37 .
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- arethuza 8y agoI'm 53 - I can remember news stories about HOTOL when I was in high school! Mind you - it would be fantastic to see this become a reality.
- MadTimbo 8y agoI am the same and can remember getting excited about it back in the day. I find it difficult to regain that excitement. This is especially true given the things that companies like SpaceX have achieved, let alone what they are working on.
- bloopernova 8y agoI was fairly young at the time but still remember _Tomorrow's World_ (A BBC TV show about science and inventions) talking about HOTOL. To ~6 year old me, raised on watching Thunderbirds, Star Trek and NASA launches, it felt great that we'd be getting our very own Shuttle. Much much older me loves messing around with scramjets and air-breathing rockets in Kerbal Space Program. Or spending real-world months exploring the Perseus Arm of the Milky Way in Elite: Dangerous. I guess our imagination always outstripped our ability, but to be honest I don't mind so much nowadays. Mostly because I'm partially disabled and would never get on any kind of space or Mars missions to start with.
- noir_lord 8y agoBumbling around out in the fringes is one of the best things about ED I find. No man's sky is worth a look if you like the explorer aspect as well. Universe is vast and varied and it's come a long way since the disaster that was it it's launch.
- api 8y agoVTVL (vertical takeoff, vertical landing) rockets have been talked about since sci-fi in the 30s and seriously since the 50s. We only just started getting real ones (SpaceX, Blue Origin), though in the 90s there was a prototype called the DC-X that proved the concept at a smaller scale. You can find DC-X videos on YouTube. The fact that something was talked about long ago and we don't have it yet doesn't necessarily mean there's something wrong with the idea. Sometimes all it takes is for someone to just do the engineering, which with high-capital stuff means it also takes someone being willing to pay for it. Of course the other case is things like net-positive fusion where people have been doing the engineering but it's f'ing hard. Still given the progress that has been made on fusion I get the sense we could do it if we spent more and put more parallel effort into it.
- syntaxing 8y agoIs this equivalent to a SC/RAM jet engine?
- baybal2 8y agoNo, it is very different
- bibyte 8y agoI wonder if this technology will ever be viable for commercial flights in the future. What the safety procedures would look like at that speed.
- short_sells_poo 8y agoI'd imagine the cockpit would need to be fully shielded? Just as a fun exercise, let's calculate the kinetic energy of a 3kg goose impacting the airplane at 5000 kmh: The formula is (m*v^2)/2. Plugging in the figures, we get 2.9 MJ, or the equivalent of a little more than half a kg of TNT. Not bad :D
- m-i-l 8y agoIt doesn't reach 5000kmh until 26km altitude[0], but the highest geese have been reported is 9km altitude[1], so I would assume it would only be in danger of encountering geese at speeds lower than 5000kmh. (Still likely to be at pretty fast speeds though.) [0] https://en.wikipedia.org/wiki/Skylon_(spacecraft) https://en.wikipedia.org/wiki/Skylon_(spacecraft) [1] https://en.wikipedia.org/wiki/Canada_goose https://en.wikipedia.org/wiki/Canada_goose
- Hendrikto 8y agoGeese don’t fly at the height where this speed is reached.
- ethbro 8y agoMy 90s childhood education based on pirated floppies was apparently deficient in the flight habits of geese, then: https://www.myabandonware.com/game/star-goose-ix https://www.myabandonware.com/game/star-goose-ix Thanks for the correction, HN!
- umeshunni 8y agoOut of curiosity, how do conventional rockets deal with bird impacts?
- danielmg 8y ago
- growlist 8y agoI just hope they've got the IP well locked down. Bound to be lots of envious eyes on this tech!
- Reason077 8y agoHow does this compare to Concorde, and contemporary aircraft, with regards to emissions and noise levels? Could a hypersonic “plane” operate from ordinary airports near cities, or would it need to be operated from remote, unpopulated areas for environmental reasons?
- baybal2 8y agoSonic booms had little to do with Concorde ban... The same way, modern noise level limits on airplanes were pretty much imposed to prevent soviet made aircraft from flooding the market after USSR collapse
- kitd 8y agoNot just sonic booms though. Those engines were spectacularly loud going over populated areas. It used to come over me in the western edges of London on a regular basis, and the whole earth shook when it did.
- baybal2 8y agoWas it so much worse than that of regular jet? I grew up near 2 airfields with rather intense traffic, with one hosting the infamous tu95, and military jets regularly engaging afterburner. I say, the noise of a big city during day is incomparably louder than that...
- close04 8y agoDo you mind me asking which city that is? I'm curious because after living in multiple big cities I found that sometimes one city was much louder than living next to the huge airport of another city. This being said regular passenger planes are not that noisy compared to military and supersonic ones.
- Reason077 8y agoI live in London and in my experience, the vast majority of problematic urban noise comes from two sources: overflying aircraft (mostly from to LHR and LCY airports), and modified or poorly maintained motorcycles. Aircraft are improving with each generation but are still extremely noisy when they're directly overflying you, even many miles from the airport. While there are certainly other sources of urban noise, like heavy goods vehicles and construction, these are strictly regulated and enforced with regards to operating times, etc in the UK - while noise from aircraft and private vehicles is not. Sirens (fire, ambulance, police) can also be very loud, but I'll give them a pass because they are actually serving a useful purpose and saving lives. In the future when vehicles are quieter due to electrification, I think we'll be able to reduce the volume of emergency sirens too.
- kristianp 8y agoThis might be competing with SpaceX BFR taking passengers point to point. I would bet on the BFR being more likely, proven technology vs new tech.
- russfink 8y agoHow much operational weight (fuel, power source) is there compared to other technologies? What about range?
- z3phyr 8y agoI use air breathing engines for small single stage orbital vehicles in KSP. They are much more fun to fly, albeit you have to stay in atmosphere for a longer time due to very low degree of ascent to gain speed :) If I have to go further, I make it two stage, with the last stage traditional booster stage. Anything bigger than that tends to fail though.
- jaimex2 8y agoSo its a two in one engine? neat idea, hoping it goes well. This sounds a bit nicer than blasting at high gs for quick travel around the planet.
- salimmadjd 8y agoThis is very cool. But, there are two ways to make your trips shorter: 1 - make them feel shorter by providing some luxury, comfort, ability to sleep watching movies, or remaining predictive, etc. 2 - go faster and reduce the travel time. There is a cost/benefits points where 1 vs 2 will not make economic sense, even for very wealthy. This is why I think, this kind of technology will mostly work and see demands in military applications and not so much for jet-setting around the world.
- TrevorJ 8y agoEven with current airplanes, for most trips the hassle is all the stuff that involves getting on the plane in the first place. Once you are in your seat, you can either relax or by relatively productive with your laptop+in-flight wifi.
- diminoten 8y agoRelaxing in economy is pretty difficult...
- hinkley 8y agoThat's why high speed trains are displacing short plane flights in, for instance, Japan. (IIRC the trains often go closer to your real destination as well. Planes get pushed to the less influential suburbs due to noise problems)
- fataliss 8y agoOn a 20h+ flight to Australia, I guarantee you, you will want it any possible minute shorter. Not even mentioning how shorter travel time could help with Jet-Lag. I can see many reasons why we may want to push both in the 1 and 2 categories!
- TrevorJ 8y agoRight, I agree. But I suspect these types of flights make up a fraction of the total number of business related flights in a year. I can't prove that though, would be interesting to see some figures on that.
- pfdietz 8y ago"Fully reusable Spacex Rockets would be lower cost than Skylon spaceplanes" https://www.nextbigfuture.com/2017/08/fully-reusable-spacex-rockets-would-be-lower-cost-than-skylon-spaceplanes.html https://www.nextbigfuture.com/2017/08/fully-reusable-spacex-... It's really difficult to beat rockets for launch to orbit. Air breathing may make more sense for cruise missions.