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Scientists unveil plans for a £6bn 'spaceplane'


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#46 neoadorable

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Posted 27 October 2012 - 04:40

thanks for keeping this going Doc! Those pics look cool. How high of an orbit are we talking about, remind me?


#47 DocM

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Posted 27 October 2012 - 23:33

They spec 85,000 ft air breathing and >124 miles onexoatmospheric, but they also talk of visiting the ISS and that's 250 miles.

#48 +SharpGreen

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Posted 27 October 2012 - 23:54

What does being able to rapidly cool air have to do with extremely fast flight?

#49 Zlain

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Posted 28 October 2012 - 00:08

What does being able to rapidly cool air have to do with extremely fast flight?


All fluid flow, if assumed a continuum and constant viscosity, is governed by the Navier-Stokes equations. The three sets of equations are continuity, momentum and energy. At most speeds under say, Mach 0.3, we can generally ignore the energy equation because we can assume the density remains constant. This "decouples" one equation from the three, so we can decouple the energy equation since we only have two unknowns and two variables, pressure and velocity. At higher Mach numbers, compressibility becomes more important and we can't assume a constant density anymore. Moreover, at very high Mach numbers, say M = 5 (hypersonic), the flow regime is dominated by heating effects. I have never studied hypersonic aerodynamics but I'm sure you'll appreciate, with re-entry of the space shuttle for instance, the vehicle speed s substantially high such that the aerodynamic heating effects are very important - hence one reason we might have to cool the materials. In terms of the air, we may have to cool that so that we can actually slow it down fast enough to react with the fuel - at least that is what they do in ramjets. Bare in mind too that the higher you go in the atmosphere, the less true the assumption of a continuum holds, and you begin to enter low density flows or even free molecular flows so this will all change the properties of the flow regime.

#50 DocM

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Posted 28 October 2012 - 00:22

What does being able to rapidly cool air have to do with extremely fast flight?


The power produced in an engine depends largely on the quantity of fuel burned with the available oxidizer (air, liquid oxygen, nitrous oxide etc.) in it the engines combustion chamber(s.)

Roughly, more fuel burned/second = more power produced = more speed.

In air breathing turbojet engines this fuel quantity is limited by the density of the air breathed in after it's compressed by the turbines. However, no matter how good the turbines are the air will always be a gas.

In a SABRE engine the air breathed into the precooler is supercooled into a liquid, massively increasing its density and therefore how much fuel can be burned with it. It burns the fuel / oxidizer mix in an array of rocket thrusters.

At 85,000 feet it runs out of enough air to be useful so SABRE switches over to liquid oxygen stored onboard before launch to run its thrusters. This makes it a dual-cycle engine. When in this second cycle it can fly in space.

Why a dual-cycle? By using atmospheric air for the first cycle the amount of stowed oxidized for the rockets is reduced, which increases the amount of cargo that can be flown.

#51 DocM

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Posted 12 September 2013 - 17:55

Popular Science article on Skylon / SABRE

http://www.popsci.co...=MzM2NDQ2MzIyS0

#52 IsItPluggedIn

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Posted 13 September 2013 - 01:56

Page not found



#53 Shiranui

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Posted 13 September 2013 - 02:22

The UK government needs to throw money at these guys.

#54 DocM

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Posted 13 September 2013 - 02:52

Page not found


Works here. Hmmmm....

#55 IsItPluggedIn

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Posted 13 September 2013 - 03:39

Works here. Hmmmm....

Balls it redirects me because im from Australia to the .au site which doesnt have the info. Just has info from 2012.

 

I hate when sites force the redirect on you. Complaint sent.  :angry:



#56 DocM

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Posted 23 October 2013 - 22:29

A full dual-cycle (air breathing / vacuum) rocket engine on the test stand in ~2017.

The Skylon vehicle will be very similar to the space plane in the film 2001.

BBC article on UK funding: http://bbc.co.uk/new...onment-23332592

http://www.flightglo...ce-full-engine/

Reaction Engines expands research project to build full-sized air-breathing engine

The UK firm whose pre-cooler heat exchanger technology for an air breathing rocket engine was recently proven in tests to be able cool air from above 1,000 decrees Celcius to less than-120 degrees Celcius in steady state conditions, has decided to go all the way and make a full scale version of its Synergistic Air-Breathing Rocket Engine (SABRE).

The decision represents an expansion of the £240 million project to build the key elements for such an engine to which the UK government is funding £60 million via ESA. The expanded £360 million new project will now build a complete engine which it hopes to one day employ in its for its Skylon space plane design.

At the 80th anniversary celebration of the British Interplanetary Society, held in its founding city of Liverpool in October, Reaction Engines’ Managing Director and the firm’s chief engine designer, Alan Bond, noted that the new project would produce a complete engine even though it has not yet been decided whether it would be of the newer SABRE 4 iteration or the earlier SABRE 3 version. With a Specific Impulse (Isp) of 2500 seconds at lift off and at 1,600 seconds at Mach 5, the liquid hydrogen/air burning engine would be between three and five times as propulsively efficient as a conventional rocket engine before it transitioned to that mode using liquid oxgyen as an oxidiser. Bond further declined to note the key technical differences between the two engine versions. Bond remained confident about raising the funding for the project even at its new higher level.

Bond also noted the work that the European aerospace firm Thales Alenia Space is doing in defining a transfer stage design to carry satellites from Skylon’s low Earth orbit to Geostationary Earth Orbit using a ’7 to 1 resonance’ transfer orbit rendezvous technique. That is, the location of the perigee of the transfer stage’s orbit matches with the orbital location of Skylon every seven of Skylon’s orbits.
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