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Author Topic: Skylon Spaceplane  (Read 73682 times)

Offline Zootycoon

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Re: Skylon Spaceplane
« Reply #180 on: December 17, 2016, 12:11:37 am »
The space shuttle orbiter empty weight is 68 ton, which is the weight it would have been on the back of 747. I believe, while in flight  the combination was significant limited in both airspeed and max altitude as well;- this would further reduce the orbital energy input. 110 Ton is an orbiter with an integrated payload and is well beyond the payload of a 747;- any claim that the structural modification to mount it on its back could extend to that level basic wing root bending enhancement is unsupported by physics or realty.

As for your assertion relating to air density this only effects nozzle expansion ratio optimisation which is a second order effect on payload mass fraction. I would welcome you to publish the physics which shows that kinetic energy is not the sole dominant factor in getting a payload into orbit. 

Sure a two stage to orbit concept gives the ability for launch point selection but that wasn't the point, a single stage such as Skylon can offer the same flexibility.

Pegasus's Tristar was the last one flying in the world because they deliberately chose to control costs by using obsolete equipment. Nothing wrong with that but is show how marginal the business case is.


Offline steelpillow

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Re: Skylon Spaceplane
« Reply #181 on: December 17, 2016, 02:51:29 am »
I would welcome you to publish the physics which shows that kinetic energy is not the sole dominant factor in getting a payload into orbit. 
Of course this has always been the prime rationale for multi-stage launch, as was first realised in the mid-twentieth century and ever since then multi-stage has been the only possible way to attain orbit. That Zootycon is using the same rationale to try and justify SSO technology over multi-stage is - what, ironic perhaps? SABRE makes it technically possible but it doesn't change the proven economic advantage of multi-stage.

Second-best is a subsonic COTS (commercial-off-the-shelf) mothership with SABRE upper stage. As British Aerospace found donkeys years ago (and contrary to Zootycon's dreams), this is the cheapest and lowest-risk orbiter to develop.  And as Pegasus has amply demonstrated, a conventional mothership brings operational flexibilities which have high value in themselves.

Better is a suborbital SABRE-powered mothership. It might even borrow a trick from the Shuttle, with the orbiter's conventional rocket engine providing boost for takeoff. But that's two specialist craft, with twice the development cost and the risk squared. Let's do it the easy way first.

You don't even need SABRE. An atmospheric mothership, suborbital rocket second stage and rocket orbiter would have been viable fifty years ago - think B52 plus X-15 with disposable orbiter hung beneath, then refine. But that refining triples the development cost, so nobody ever dared go there.

Exercise for the student: Taking the Virgin Galactic two-stage suborbital launch system as a starting point, how is it best developed to give orbital capability? SABRE for the mothership? SABRE for the second stage? A new rocket third stage? Richard Branson would love to know!

But if you are willing to set aside orbital flight for now then, whether or not you believe that SSO will ultimately triumph, a sub-orbital Skylon is an obvious next step.
« Last Edit: December 19, 2016, 10:50:47 am by steelpillow »
Cheers.

Offline SteveO

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Re: Skylon Spaceplane
« Reply #182 on: December 18, 2016, 09:21:26 am »
Hmmm... not much to look at anymore on the new website https://www.reactionengines.co.uk

Hopefully the lack of documents, images and videos indicates real world progress is being made!

Offline mz

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Re: Skylon Spaceplane
« Reply #183 on: December 18, 2016, 01:28:40 pm »
The space shuttle orbiter empty weight is 68 ton, which is the weight it would have been on the back of 747. I believe, while in flight  the combination was significant limited in both airspeed and max altitude as well;- this would further reduce the orbital energy input. 110 Ton is an orbiter with an integrated payload and is well beyond the payload of a 747;- any claim that the structural modification to mount it on its back could extend to that level basic wing root bending enhancement is unsupported by physics or realty.

As for your assertion relating to air density this only effects nozzle expansion ratio optimisation which is a second order effect on payload mass fraction. I would welcome you to publish the physics which shows that kinetic energy is not the sole dominant factor in getting a payload into orbit. 

Sure a two stage to orbit concept gives the ability for launch point selection but that wasn't the point, a single stage such as Skylon can offer the same flexibility.

Pegasus's Tristar was the last one flying in the world because they deliberately chose to control costs by using obsolete equipment. Nothing wrong with that but is show how marginal the business case is.

initial mass / final mass = exp ( delta vee / effective exhaust velocity)

The effective exhaust velocity can be made significantly higher for lower ambient pressures. Don't have info on 20% sea level air pressure, or whatever Pegasus is launched at, but here's some back of the envelope:

For example the SpaceX Merlin engine has a nozzle extension on the vacuum version.

Merlin 1C with sea level nozzle
Sea level: 350 kN, 275 s
Vacuum: 400 kN, 304 s

Merlin 1C with vacuum nozzle extension
Vacuum: 411 kN, 342 s

For example if you need 6 km/s of stage delta vee, with a normal ISP of 3 km/s you need e^(6/3) = e^2 = 7.4 mass ratio.
While with the air launch ISP 3.4 km/s you only need a 5.8 mass ratio.

You could downsize the first stage and leave out some engines, to save on cost per launch etc...

Offline Byeman

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Re: Skylon Spaceplane
« Reply #184 on: December 19, 2016, 08:52:17 am »
The space shuttle orbiter empty weight is 68 ton, which is the weight it would have been on the back of 747. I believe, while in flight  the combination was significant limited in both airspeed and max altitude as well;- this would further reduce the orbital energy input. 110 Ton is an orbiter with an integrated payload and is well beyond the payload of a 747;- any claim that the structural modification to mount it on its back could extend to that level basic wing root bending enhancement is unsupported by physics or realty.

2.  As for your assertion relating to air density this only effects nozzle expansion ratio optimisation which is a second order effect on payload mass fraction.

3.   I would welcome you to publish the physics which shows that kinetic energy is not the sole dominant factor in getting a payload into orbit. 



The fact that you are using wrong data just shows that the rest of your posts are suspect and you don't know what you are talking about. I make no "claims", I am only stating facts.

1.  When the shuttle orbiter landed at Edwards AFB and was ferried back to KSC, it was not empty, it still had some fluids onboard and payload.  And if the payload was a Spacelab, it was a full up payload. 
Here is a document covering the first 91 missions and it lists the ferry weights.  One was almost 230k pounds (i.e. 115 tons)

2.  Just as your assertion about  "combination was significant limited in both airspeed and max altitude as well;- this would further reduce the orbital energy input.".  Air launch is not about energy input.  Airspeed and altitude at launch figure little into the deltaV required. 
And as for my point on air density,  it is not an assertion on  nozzle expansion.  The benefit from air launch due to lower air density is less drag and dynamic pressure. 

3.  Never made any post that does not say otherwise.  However, there are other considerations and trades that affect what it costs to provide the kinetic energy.   
« Last Edit: December 24, 2016, 12:26:49 pm by Byeman »

Offline steelpillow

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Re: Skylon Spaceplane
« Reply #185 on: December 19, 2016, 10:57:49 am »
Hmmm... not much to look at anymore on the new website https://www.reactionengines.co.uk

Hopefully the lack of documents, images and videos indicates real world progress is being made!

Hedging their bets now:
"SABRE class engines are applicable in both multi-stage and single-stage architectures."
https://www.reactionengines.co.uk/vehicles/
Cheers.

Offline Ian33

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Re: Skylon Spaceplane
« Reply #186 on: December 19, 2016, 12:46:52 pm »
Hmmm... not much to look at anymore on the new website https://www.reactionengines.co.uk

Hopefully the lack of documents, images and videos indicates real world progress is being made!

Hedging their bets now:
"SABRE class engines are applicable in both multi-stage and single-stage architectures."
https://www.reactionengines.co.uk/vehicles/

No, not hedging their bets, fully realising the potential for small, bomber sized version as well as they big boys full sized monster to take payload to orbit.  I fully expect to see a little clip mid to late 2017 of such power plants demonstrated.
Resident know nothing and Dale Brown reader... Feel free to help me graduate from crayons!

Offline steelpillow

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Re: Skylon Spaceplane
« Reply #187 on: December 20, 2016, 02:58:21 pm »
...fully realising the potential for small, bomber sized version as well as they big boys full sized monster to take payload to orbit.
That's what I said, hedging their bets. :)
Cheers.

Offline bobbymike

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"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

"On what principle is it that with nothing but improvement behind us, we are to expect nothing but deterioration before us?" - Lord Macaulay

Offline bobbymike

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"The real man smiles in trouble, gathers strength from distress, and grows brave by reflection." - Thomas Paine

"On what principle is it that with nothing but improvement behind us, we are to expect nothing but deterioration before us?" - Lord Macaulay

Offline Archibald

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Re: Skylon Spaceplane
« Reply #190 on: February 23, 2017, 11:33:20 pm »
Skylon on backburner until the 2030s. Et merde !!  :-\
Conservatoire de l'Air et de l'Espace d'Aquitaine - Bordeaux - Mérignac / Dassault aviation museum
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Offline Flyaway

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Re: Skylon Spaceplane
« Reply #191 on: May 04, 2017, 07:20:29 am »
Reaction Engines begins construction of UK rocket engine test facility

Reaction Engines Ltd. today began construction of a new engine test facility where it plans to undertake the first ground based demonstration of its revolutionary SABRE™ air-breathing rocket engine.

The test facility at Westcott, Buckinghamshire, UK  will enable Reaction Engines to test critical subsystems along with the testing of a SABRE engine core, which will commence in 2020.

The project represents a substantial investment for Reaction Engines, which will consist of a multi-purpose propulsion test stand designed to accommodate various test engine configurations, an assembly building, workshops, offices and control room.  The location of workshops and other support facilities alongside the test stand will enable configuration changes to the engine to take place at the site, reducing the down time between testing phases and accelerating the development programme of the SABRE engine.

To mark the start of construction, Mark Thomas, CEO, Reaction Engines undertook a ground breaking ceremony with Franco Ongaro, Director of Technology, Engineering and Quality, European Space Agency (ESA); Dr. Chris Castelli, Director, Programmes, UK Space Agency and Richard Harrington, CEO, Buckinghamshire Thames Valley LEP.

Mark Thomas, CEO, Reaction Engines said:

“This is another exciting step forward in development of Reaction Engines’ SABRE engine and a visible demonstration of the UK’s commitment to the programme.  I look forward to seeing this unique facility take shape and commencing our core engine testing, which will be a defining moment for aerospace.”

Franco Ongaro, Director of Technology, Engineering and Quality, ESA said:

“The opening of this new test facility at Westcott Today marks an historical moment for the European Aerospace industry and for the UK research and development in rocket propulsion. This facility will enable the ground test of the SABRE engine cycle, opening the way to the first flight tests, and to a new era. The European Space Agency is proud of this partnership with industry and the UK Space Agency, to which we bring our technical competence, which has supported the SABRE development to this stage, and we are confident, to its future flight success.”

The construction of the SABRE engine test facility is a significant milestone. The company has already successfully undertaken testing of the engine’s pre-cooler and thrust chamber technologies, and will undertake further ground-based high-temperature testing of the pre-cooler early in 2018.

The test facility is located in the Westcott Venture Park, a location with a strong history of rocket propulsion research, having been used to test various UK rocket projects since 1946, including the Blue Streak and Black Arrow programmes. In 2016 the UK Space Agency selected Westcott as the UK’s National Space Propulsion Test Facility and the site is now home to a number of space propulsion and satellite technology companies.

https://www.reactionengines.co.uk/reaction-engines-begins-construction-uk-rocket-engine-test-facility/

Offline FighterJock

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Re: Skylon Spaceplane
« Reply #192 on: May 04, 2017, 08:09:00 am »
That is brilliant news for Reaction Engines.   B)

Offline Flyaway

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Re: Skylon Spaceplane
« Reply #193 on: May 04, 2017, 08:47:52 am »
Quote
Reaction Engines is proud to announce ground is now broken on our multi-£M #SABRETF1 core engine test facility @WestcottVP

Pictures on the link below.

https://mobile.twitter.com/ReactionEngines/status/860147329260822528

Offline Flyaway

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Re: Skylon Spaceplane
« Reply #194 on: May 10, 2017, 03:08:07 am »


Quote
Published on 8 May 2017

Animation of Reaction Engines SABRE TF1 test facility at Westcott Venture Park near Aylesbury.