The Reaction Engines Skylon Master Thread (1)

[Warren Platts]

1.  Skylon and Musk vehicles have nothing in common.

They have at least the same objective:  designing a reusable spacecraft.

As Musk told to the Royal Aeronautical Society (at about 7:29):

« In the past, whenever I've done the basic maths on having an air-breathing stage, it didn't seem to make sense.  But I could be wrong about that. »

He clearly seem not to have put a lot of thoughts in it and admits he could be wrong.  Surely if he was actually wrong, he would like to know it.

Sounds to me he's clearly talking about Stratolaunch, subsonic, Birdzilla--of which he's right that the < 5% improvement in performance is not worth the expense and trouble of maintaining the biggest airplane in world history.

Skylon is a quite different beast, and it's an SSTO after all, and not an air-breathing [1st] stage.

[Andrew_W]

Sounds to me he's clearly talking about Stratolaunch, subsonic, Birdzilla--of which he's right that the < 5% improvement in performance is not worth the expense and trouble of maintaining the biggest airplane in world history.

Skylon is a quite different beast, and it's an SSTO after all, and not an air-breathing [1st] stage.

Where do you get the <5% from?

[Lars_J]

it will be for aeronautics, as it will allow a return of a supersonic airliner.

Very sceptical about supersonic airliners. Their usage will always be limited since they are not allowed to fly over land (yes, even those supposedly silent designs from boeing).

Well, amazingly enough, the route from Europe to Australia does pretty much not fly over any land at all:

The shortest distance is over mostly land: http://www.niharsworld.com/map.html?lat1=0.9043278075104286&long1=-0.0286282478695181&lat2=-0.6033603224144397&long2=2.640721943361909&d=17131.87518444603

[flymetothemoon]

The shortest distance is over mostly land:

Eh?

[Crispy]

Well, amazingly enough, the route from Europe to Australia does pretty much not fly over any land at all:

The shortest distance is over mostly land: http://www.niharsworld.com/map.html?lat1=0.9043278075104286&long1=-0.0286282478695181&lat2=-0.6033603224144397&long2=2.640721943361909&d=17131.87518444603

When you're doing Mach 5, a few thousand km here or there isn't going to make much difference

[Elmar Moelzer]

The shortest distance is over mostly land

Yes, but REL proposed a different route for their planes that takes a slight detour (over the north pole and down the bering strait). That way they are not going over much land at all.

[Lars_J]

The shortest distance is over mostly land:

Eh?

Did you bother to check the link? That is the shortest distance between London and Sydney.

[Longstaff]

The shortest distance is over mostly land:

Eh?

Did you bother to check the link? That is the shortest distance between London and Sydney.

But we choose to go north, over the pole and through the Bering Straight, then one way to Tokyo, the other way to LA, or straight on to Oz. All over the sea with no disturbance.

Also, please see attachement for press release by REL today.

Best to all,

Roger Longstaff

[Citizen Wolf]

Congrats to all at Reaction Engines. Let's hope the next phase in development goes without any major delays.

[flymetothemoon]

The shortest distance is over mostly land:

Eh?

Did you bother to check the link? That is the shortest distance between London and Sydney.

But we choose to go north, over the pole and through the Bering Straight, then one way to Tokyo, the other way to LA, or straight on to Oz. All over the sea with no disturbance.

Also, please see attachement for press release by REL today.

Best to all,

Roger Longstaff

Thanks Roger! x2

[Lars_J]

The shortest distance is over mostly land:

Eh?

Did you bother to check the link? That is the shortest distance between London and Sydney.

But we choose to go north, over the pole and through the Bering Straight, then one way to Tokyo, the other way to LA, or straight on to Oz. All over the sea with no disturbance.

Ok, FYI - here is a link that compares those paths with the optimal/shortest paths:
http://www.gcmap.com/mapui?P=lhr-syd%2C+lhr-padu-syd%2C+%0D%0Alhr-lax%2C+lhr-padu-lax%2C+%0D%0Alhr-nrt%2C+lhr-padu-nrt&MS=wls&MP=a&RC=cyan&DU=mi
This map is centered at London, and in this projection the shortest travel distance is a straight line. (PADU was the closest airport I could find to bering strait)

London-Sydney - 10.5% longer (not bad)
London-Los Angeles - 43.4% longer
London-Tokyo - 32.9% longer

[flymetothemoon]

The shortest distance is over mostly land:

Eh?

Did you bother to check the link? That is the shortest distance between London and Sydney.

But we choose to go north, over the pole and through the Bering Straight, then one way to Tokyo, the other way to LA, or straight on to Oz. All over the sea with no disturbance.

Ok, FYI - here is a link that compares those paths with the optimal/shortest paths:
http://www.gcmap.com/mapui?P=lhr-syd%2C+lhr-padu-syd%2C+%0D%0Alhr-lax%2C+lhr-padu-lax%2C+%0D%0Alhr-nrt%2C+lhr-padu-nrt&MS=wls&MP=a&RC=cyan&DU=mi
This map is centered at London, and in this projection the shortest travel distance is a straight line. (PADU was the closest airport I could find to bering strait)

London-Sydney - 10.5% longer (not bad)
London-Los Angeles - 43.4% longer
London-Tokyo - 32.9% longer

Right. But it is either longer, or not at all. Not at all wouldn't be a very good outcome for the new plane!

[flymetothemoon]

Also, please see attachement for press release by REL today.

Best to all,

Roger Longstaff

Alan Bond:
"This is the proudest moment of my life.”

We're very proud of you too Alan! 

[Citizen Wolf]

One wonders whether Mr Musk will have a more considered reaction regarding skylon the next time he's quizzed on the subject.

[Andrew_W]

Great news, lhr-akl 0.7% longer!

[Elmar Moelzer]

Oh, yes congrats to everyone at REL. Great to see some innovation come out of Europe! Now go build me a spaceplane, already!

[Rugoz]

Regarding economics, I did a little calculation:

Lets assume the 12 billion development cost are evenly distributed over a 10 year period. With an interest rate of 5% you get a present value for costs of 9.2661b. After 10 years of development the investors funding skylon will have a 10 year monopoly on the tech (until the chinese have copied it). To break even they have to make 1.8171b profit every year for 10 years.

I will assume skylon will take over the entire commercial launch market. In 2011 there were 18 commercial launches, I'll count the ariane 5 launches twice so that makes 22. Consequently they have to make 82.6 million profit for every launch  . Of course they could offer at lower price to create more demand and a higher flight rate, but that also means lower profits per launch, so if we assume a low price elasticity of demand for satellite launches its probably best to price marginally below competitors.

Anyway, you get my point. 

[Jim]

One wonders whether Mr Musk will have a more considered reaction regarding skylon the next time he's quizzed on the subject.

Why?  Spacex is flying and making money

[Citizen Wolf]

@Jim

Microsoft makes heaps of cash, but they still know about Apple. They'd look silly if they didn't.

[BobCarver]

Spacex is flying and making money

Didn't the buggy whip manufacturers say something similar when the horseless carriage came out? It's not just Esa that needs to start worrying about Ariane. If SKYLONs can service the ISS, SpaceX might find the gravy train ending.