Whats wrong with Skylon?

[ModZero]

48 minutes ago, tater said:

Heck, em-drive is more mature than the skyline engine

Oh you have got to be kidding me. Why stop there, add Alcubierre drive and time travel. At least SABRE has a precooler and people who have basic idea about physics on its side.

[tater]

I don't think em-drive is a thing, but you could actually build one and fly it in very short order.

Until they have a functioning testbed, they have no more that Orion ever had (we had nuclear bombs, and big pieces of metal). They've been working on it for decades.

[blowfish]

10 minutes ago, tater said:

I don't think em-drive is a thing, but you could actually build one and fly it in very short order.

Until they have a functioning testbed, they have no more that Orion ever had (we had nuclear bombs, and big pieces of metal). They've been working on it for decades.

Sure, and we also have compressors and precoolers and rocket nozzles (REL had a successful test of their precooler technology recently).  In both cases, you don't really figure out all the details until you actually try to build one.

[ModZero]

48 minutes ago, tater said:

I don't think em-drive is a thing, but you could actually build one and fly it in very short order.

Only if you kick one very hard.

EDIT: I'm getting annoyed, because while Skylon might be a pie-in-the-sky solution-in-search-of-a-problem silly idea that looks cool, at least nobody is claiming it's propelled by magic, goodwill and shards of broken laws of physics.

Edited April 12, 2016 by ModZero

[tater]

Just now, ModZero said:

Only if you kick one very hard.

I'm not saying it would do anything, lol. I'm saying you could build it, turn it on, and then be able to say yes or no if it worked. Since you could likely make one in a garage, it could be done on a cubesat in no time. Skylon has what, one part that isn't imaginary? It's a cool idea, but at this point that's all it is, an idea. 

[Nuke]

i cant find any thermodynamic reason why the sabre wont work as advertised. the only gotcha is the icing problem they claimed to have solved. i have some concerns about the fragility of the precooler during runway operations, debris and bird strikes would be certain death. i suppose that would best be solved by lifting off in rocket mode and only open the inlets once enough ground clearance is established. of course switching modes that close to ground may introduce other issues. like if for some reason the air breathing mode fails to initiate, the engines stall, and you crash full of liquid hydrogen.

[ModZero]

20 minutes ago, tater said:

I'm not saying it would do anything, lol. I'm saying you could build it, turn it on, and then be able to say yes or no if it worked.

There are two problems with this: one is, I could say the same about my cup of tea, if I glued a switch to it. 2nd, people actually did that quite a lot, it turned out it did nothing. Which wasn't particularly surprising. So even if Skylon was completely imaginary, it would still be ahead of EM drive.

And the reason I'm quite angry here is, in contrast to EM drive there's a lot of work by competent people put into SABRE. The economics are against them, but they put honest work and real technical (if not business) competence into it. Comparing it to some technobabble scam is insulting.

[tater]

I was merely comparing the existence of an actual engine, even if one is nonsense (or just ablating itself).

So we have an almost certainly fantasy engine that is actually built, vs a plausible engine that doesn't exist.

[tater]

I should add that I'd be incredibly excited to see skylon actually exist as more than a powerpoint presentation. I felt the same way about NASP back in the day.

Edited April 12, 2016 by tater

[lude]

Tater what more than 

do you actually need? It's not like the chassis and ceramic composite are imaginary things, never having been invented or used ever.

[Steel]

1 hour ago, lude said:

Tater what more than 

do you actually need? It's not like the chassis and ceramic composite are imaginary things, never having been invented or used ever.

Yeah... That's not a SABRE engine, that's the jet engine from a Sabre aircraft.

[lude]

3 hours ago, Steel said:

Yeah... That's not a SABRE engine, that's the jet engine from a Sabre aircraft.

damn ^^

 

but this isn't  https://youtu.be/qgtZCXYmkDU?t=149

[Steel]

41 minutes ago, lude said:

damn ^^

 

but this isn't  https://youtu.be/qgtZCXYmkDU?t=149

I believe that's the precooler demonstration. That's the only part that has been actually built and tested so far.

[lude]

4 minutes ago, Steel said:

I believe that's the precooler demonstration. That's the only part that has been actually built and tested so far.

yes and they're saying it's the only real barrier since the rest of the technology is pretty vanilla and it's not only the engineers in that video (or the bbc one) saying that it's also a popular statement in online sources

 

much like when they invented and build shcramjets they didn't need to put much thought into designing the ramjet part

 

they will probably still spend quite some time with the precooler since that's pretty much new lands

 

much like their novel nozzle isn't really that novel (see advanced nozzle project)

[Steel]

9 minutes ago, lude said:

yes and they're saying it's the only real barrier since the rest of the technology is pretty vanilla and it's not only the engineers in that video (or the bbc one) saying that it's also a popular statement in online sources

 

much like when they invented and build shcramjets they didn't need to put much thought into designing the ramjet part

 

they will probably still spend quite some time with the precooler since that's pretty much new lands

 

much like their novel nozzle isn't really that novel (see advanced nozzle project)

It may be that all the other parts are much better understood, but in any project like this the systems integration will take a considerable amount of time. It may be that they can put together an engine and test it and it will be fine, but I will reserve judgement until they do it, but by the look of things it'll be 5-10 years until then.

[Kryten]

4 minutes ago, Steel said:

It may be that all the other parts are much better understood, but in any project like this the systems integration will take a considerable amount of time. It may be that they can put together an engine and test it and it will be fine, but I will reserve judgement until they do it, but by the look of things it'll be 5-10 years until then.

And as with any SSTO, much of an issue in any of the other systems could easily make the whole thing unable to reach orbit. X-33 had problems severe enough to do that just designing a conformal carbon composite fuel tank, it's not hard to see how something as exotic as a ceramic monocoque airframe doing similar. 

[Steel]

1 minute ago, Kryten said:

And as with any SSTO, much of an issue in any of the other systems could easily make the whole thing unable to reach orbit. X-33 had problems severe enough to do that just designing a conformal carbon composite fuel tank, it's not hard to see how something as exotic as a ceramic monocoque airframe doing similar. 

Oh yeah definitely! What I said before was just the engine, I can't see the actual Skylon SSTO (in whatever form it ends up taking) flying for decades.

[Nuke]

i think it would simply be better to bring the engines to market and let the various aerospace agencies, who actually have experience building air and space craft, design and build their own space planes around them.