justify your opinion, it's not worth the e-paper it's written on.
But, there are a lot of smart guys who have looked at the SKYLON design and said it will work.
Quote from: BobCarver on 11/05/2012 02:30 pmJim, you have a reputation as a smart guy and it's probably well deserved. But, there are a lot of smart guys who have looked at the SKYLON design and said it will work.Actually, not true, not enough of the right smart people have looked at it. The fact that there is no other similar system in development or that there is not a bunch of money being thrown at it is telling. Also, I define "working" as being cheaper that existing systems. I don't mean like the shuttle which flew but did nothing to reduce the cost of spacelaunch.
Jim, you have a reputation as a smart guy and it's probably well deserved. But, there are a lot of smart guys who have looked at the SKYLON design and said it will work.
* Technologically: this thing REQUIRES breakthrough developments in several different areas. There are very, very few examples of large scale projects who have actually succeeded from such a state of technological maturity. I don't remember even one.
Potential show-stoppers - what could they be?The whole SABRE principle being wrong?Precoolers not working or icing the engine?Engine not producing enough thrust for orbit?Thermal protection system inadequate?or something else?
Quote from: pippin on 11/05/2012 03:09 pm* Technologically: this thing REQUIRES breakthrough developments in several different areas. There are very, very few examples of large scale projects who have actually succeeded from such a state of technological maturity. I don't remember even one.This claim was previously made and has already been debunked on this very thread. To me, a breakthrough technology is one which has not been demonstrated in real life. I challenge you to name one technology which has not already been demonstrated in reality. Either that or redefine "breakthrough" as you understand it.
break·through/ˈbrākˌTHro͞o/Noun: A sudden, dramatic, and important discovery or development, esp. in science. A significant and dramatic overcoming of a perceived obstacle, allowing the completion of a process.
I don't believe that.It their word is worth anything they might have said that it COULD work.
And this particular one has challenges in every single respect:* Technologically: this thing REQUIRES breakthrough developments in several different areas. There are very, very few examples of large scale projects who have actually succeeded from such a state of technological maturity. I don't remember even one.
* Financing: It's not like launch services right now are something you can make big money on commercially so financing for a project of this scale will have to involve governments.
Which will have a lot of political interests, are notoriously short on money for investments right now and so on.
AFAIK Skylon doesn't have a financing, yet.
* Demand: So far, RLVs haven't shown to be feasible because there weren't enough payloads.
Of course it's also a question of cost but as long as nobody just funds a large scale project just for fun it's a chicken-and-egg-situation you don't easily get out of.
* Project Management: Developing technology and developing an operational business are two completely different animals. I know what I'm talking about here. Many a good projects with very bright people on them have failed just trying to bring together EXISTING technology. I don't say it can't be done, I just say that this part alone has a failure probability of maybe 50% or so, even if everything else works out fine.
* Politics: Since you need governments to fund, regulate and buy launches on this thing, you depend on their interest. Is the UK going to finance this alone? No? Then OK, who else has an interest in this. Another aspect with at LEAST 50% failure probability.
This is a cool project and all of what it's trying to do may be feasible (I can't judge on that) on it's own,
but even then, putting it all together let's you end up with a probability of success in the single-digit percentages or so.
Actually, not true, not enough of the right smart people have looked at it. The fact that there is no other similar system in development or that there is not a bunch of money being thrown at it is telling. Also, I define "working" as being cheaper that existing systems. I don't mean like the shuttle which flew but did nothing to reduce the cost of spacelaunch.
You might like to consider the history of Sealaunch. While it's struggling (I'm not sure of its current status but it seems rocky) the company that *builds* its LVs is running fine.
The Kistler K1 (staffed mainly by ex-NASA engineers) burned through c$900m of private VC funding
Who would you have preferred to have done it
@pippin: REL have a TPS which is well proven. Breakthrough not required. "Fully-integrated" may be your idea of "breakthrough" but it sure isn't an industry standard. Here's what google says:Quotebreak·through/ˈbrākˌTHro͞o/Noun: A sudden, dramatic, and important discovery or development, esp. in science. A significant and dramatic overcoming of a perceived obstacle, allowing the completion of a process.According to your definition, the heat exchanger is still a breakthrough to be made despite the fact that it has been thoroughly tested already. You should learn to use words as they are commonly understood and not your strange interpretation of them. It creates misunderstanding and confusion to misuse well-understood concepts as you have.
Quote from: john smith 19 on 11/05/2012 05:52 pmWho would you have preferred to have done it People who have designed and built large systems that include SOTA turbomachinery
1. You might care to look up the history of the SR71 and what was state of the art when its design was started. I'd suggest that TRL's in *all* the areas that Skylon/SABRE are better than they were when Kelly Johnson started that programme. 2. REL are not planning to *operate* Skylons. This has been mentioned repeatedly. The question *their* business model has to answer is therefor "Can we identify 30 entities who (for whatever reason) would want an *asset* which will give them orbital launch capability for about $1Bn [edit]and that have the reserves or financing to afford it?" 3. True. Which is why REL have sought to avoid government *money* like the plague. Note that money is out there for large projects. A typical new semiconductor wafer fabrication plant is about $3Bn but these can be funded. 4. And if they did how would you know it? 5. And my *suspicion* is that as long as the company that builds an RLV also *operates* it that will always be the case, except *possibly* if the RLV is very small.6. That would depend on what you mean by "operational business." If you mean moving from design to *construction* of Skyon/SABRE they've been clear all along they expect the Skylon side to more to an *experienced* airframe mfg who would incorporate their work, hte way Airbus is *part* of EADS or Panavia was set up *specifically* to design and mfg the Tornado. 7. Concorde flew.