Skylon
Glad to see you bring a new level of information to the topic WW, or maybe it is just straight forward abuse? Perhaps you could explain how you think this concept would actually reduce the cost of payload to orbit ?
OAP
OAP
It reduces the cost by being fully reusable - getting 200 launches out of each airframe at least. So far rockets:
a) Are only partially reusable in the case of those that can reach orbit.
b) Have a high failure rate.
c) It's not clear that any bits have actually flown twice other than on the suborbital Blue Origin.
d) have more limits about where they can be flown from.
Against that, it's expensive but against that it may have various spinoffs (e.g. military) which will reduce the portion of the development cost that has to be paid back entirely by launcher sales. So there are various ways to look at it.
I think it would be silly not to develop the engine and then assess from there.
a) Are only partially reusable in the case of those that can reach orbit.
b) Have a high failure rate.
c) It's not clear that any bits have actually flown twice other than on the suborbital Blue Origin.
d) have more limits about where they can be flown from.
Against that, it's expensive but against that it may have various spinoffs (e.g. military) which will reduce the portion of the development cost that has to be paid back entirely by launcher sales. So there are various ways to look at it.
I think it would be silly not to develop the engine and then assess from there.
Could not agree more.
The history of engineering as a discipline, let alone aerospace, is full of examples of pontificators and pessimists who knew better - and upstarts who raised a finger, took a chance and proved their doubters wrong.
The history of engineering as a discipline, let alone aerospace, is full of examples of pontificators and pessimists who knew better - and upstarts who raised a finger, took a chance and proved their doubters wrong.
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More news on Skylon
Funding flows for UK’s ‘revolutionary’ Sabre rocket engine
Also interesting to note that there's investment in RPE Westcott uk-space-agency-to-create-4m-testing-facility
Something to consider is the number of patented technologies that REL have developed on the way, machining processes and a number of techniques which are used for cryo and space systems.
I'm hoping that they do launch a demonstrator from Prestwick and if they do my name will be on the petition to have it named fireball XL5!
Funding flows for UK’s ‘revolutionary’ Sabre rocket engine
Also interesting to note that there's investment in RPE Westcott uk-space-agency-to-create-4m-testing-facility
Something to consider is the number of patented technologies that REL have developed on the way, machining processes and a number of techniques which are used for cryo and space systems.
I'm hoping that they do launch a demonstrator from Prestwick and if they do my name will be on the petition to have it named fireball XL5!
Great! No one here understands the efficiency mismatch between the cooling ability of cryogenic fuel and its available capacity to cool superheated hypervelocity atmospheric gas (part) oxidiser (via an inert medium) across two thermal interfaces in a wingborne lifting body supporting the additional weight ( ie drag) of the industrial scale machinery necessary to achieve this process against, the efficiency of a booster loaded with pre prepared cryogenic fuel and oxidiser that requires only 150 sec to reach sub-orbital (nearly zero drag) space, in the competition to launch orbital payloads.
There may be applications for cryogenic fuel / atmospheric oxidiser engines and high-speed / very high altitude wingborne flight but, the efficient upward path to orbit is via the route of minimum time/drag as, I think, was illustrated by the Saturn V.
OAP
There may be applications for cryogenic fuel / atmospheric oxidiser engines and high-speed / very high altitude wingborne flight but, the efficient upward path to orbit is via the route of minimum time/drag as, I think, was illustrated by the Saturn V.
OAP
There may be applications for cryogenic fuel / atmospheric oxidiser engines and high-speed / very high altitude wingborne flight but, the efficient upward path to orbit is via the route of minimum time/drag as, I think, was illustrated by the Saturn V.
Even a non-expert like me knows that SABRE's advantage is that its precooler is so light compared to the amount of cooling it does - this is the main item of new technology after all. The other great realisation was that air need not be liqufied - it just has to be cold enough to compress.
We also know that oxygen is relatively heavy so that you get a great advantage (in payload) from not having to carry enough to reach Mach 5 after which SABRE behaves like a rocket.
Presumably the engineers that have done the sums don't think drag has a significantly negative effect on this outcome. After all the complete launch is only something like 15-20 minutes of engine use if I remember correctly.
I don't know how efficient these different schemes are as I am not a rocket scientist. But I do know that the aim is cost per kilo to orbit, not efficiency.
txxxxx, the skyflop "details" picture page you posted shows two hours to 28km.
Along with loads of carp such as: Space Shuttle landing speed 400 mph, lightweight equals "slower" re-entry!
There is no way that this concept will ever be built. High altitude air breathing hybrid engines may find a niche, maybe even for launching small Rockets into orbit!
OAP
Along with loads of carp such as: Space Shuttle landing speed 400 mph, lightweight equals "slower" re-entry! There is no way that this concept will ever be built. High altitude air breathing hybrid engines may find a niche, maybe even for launching small Rockets into orbit!
OAP
Ecce Homo! Loquitur...
U.S. Air Force Lays Out Air-Breathing-Engine-Powered Launcher Studies
As part of its pursuit of breakthrough propulsion systems for high-speed flight and potential access to space, the U.S. Air Force Research Laboratory (AFRL) has spent more than two years studying the novel air-breathing rocket engine system concept invented by UK-based Reaction Engines Ltd. AFRL’s studies of the Synergetic Air-Breathing Rocket Engine (SABRE) cycle, which uses atmospheric oxygen and liquid hydrogen from a standing start to above Mach 5 when it switches to onboard liquid oxygen, have shown the concept is thermodynamically feasible. The engine and innovative precooler at the heart of the cycle are ultimately aimed by Reaction at a single-stage-to-orbit (SSTO) launch vehicle dubbed Skylon.
However, while SSTO remains a long-range goal, Reaction has recrafted its ground demonstrator to reflect smaller-scale potential applications in the nearer term. AFRL, which is meanwhile working in parallel with Reaction under a cooperative research and development agreement, is for the first time outlining details of how SABRE might be used to support orbital launch missions when configured as part of a two-stage-to-orbit (TSTO) launch system. Working with Atlanta-based SpaceWorks Enterprises, AFRL has defined two initial next-generation launch system concepts: A partially reusable TSTO with a SABRE-powered booster and expendable rocket-powered second stage, and a second fully reusable option incorporating a SABRE-powered first stage and a rocket-powered upper stage. “We asked, ‘What’s a nearer-term approach to do access to space with this very interesting engine idea and precooling technology?’ and came up with this two-stage-to-orbit system,” says Barry Hellman of AFRL’s High-Speed Systems Division.
The first system is designed to place a 5,000-lb. payload into a 100-nm orbit with a 28.5-deg. inclination from Cape Canaveral AFS.. Two missions were also analyzed to determine performance to a sun-synchronous orbit at 378 nm flown from Vandenberg AFB, California, and a proposed UK spaceport site in Newquay, England.
The partially reusable concept is based on a twin-SABRE-powered winged booster. Measuring 150 ft. long, or about 4 ft. longer than a B-1B bomber, the vehicle would carry the rocket-powered second stage in a lower payload bay. “The notional concept of operations is like an aircraft with a horizontal takeoff and landing,” said Hellman at the American Institute of Aeronautics and Astronautics (AIAA) Space 2016 conference and exhibition in Long Beach, California, Sept. 13-16.
“The vehicle would accelerate to almost Mach 4.5 before transitioning to rocket mode, when it would pull up while still accelerating,” he said. “We carry the upper stage inside so it does not have to have a payload fairing or thermal protection system (TPS). That also means it has to stage at a very high altitude of over 260,000 ft. and a low dynamic pressure of about 0.8 psf. It then boosts away to orbit while the vehicle turns away and returns.” Staging would occur at about Mach 8 before the vehicle begins a gliding turn toward the launch site and briefly restarts the engines in air-breathing mode for additional boostback.
“We assumed we would have conformal hydrogen tanks and that would be another technology challenge that would have to be solved to make this design work,” Hellman said. By placing the payload underneath, no large cranes are needed to load the vehicle, and “when we get to staging, we use gravity and the payload just falls away,” he added. Hellman conceded, however, that payload bay door design will require special consideration for the TPS to handle reentry.
The vehicle’s propellant mass fraction (mass of propellant divided by the weight of the whole stage apart from the payload) “is about 0.43, and that is unheard of for access to space systems,” said Hellman. “That is what an air-breathing engine allows you to have. The bottom line is, the vehicle can make the mission with extremely low propellant-mass fractions.”
The second, fully reusable option consists of a 190-ft.-long scaled-up variant of the smaller booster and a reusable upper-stage booster. Designed to carry a 20,000-lb. payload to orbit, the 115-ft.-span booster and upper stage would collectively weigh about 1.3 million lb. at takeoff. The system would launch horizontally, and both stages would return for a horizontal landing. After deploying its payload, the upper stage would continue around the world and, with the cross-range capability of its 40-ft.-span, X-37B-like wing, recover to the launch site.
For the immediate future, the Air Force continues to focus on further evaluation of the precooler. “That is the biggest interest we have right now at AFRL,” Hellman said. “We have been looking at trying to get the funding to test the heat exchanger at higher temperatures, simulating conditions behind the inlet at Mach 3.5-5. It’s a very fascinating technology that has a lot of senior Defense Department and NASA officials excited. We are moving along slowly, though hopefully we will make more progress in the next few years.”
As part of its pursuit of breakthrough propulsion systems for high-speed flight and potential access to space, the U.S. Air Force Research Laboratory (AFRL) has spent more than two years studying the novel air-breathing rocket engine system concept invented by UK-based Reaction Engines Ltd. AFRL’s studies of the Synergetic Air-Breathing Rocket Engine (SABRE) cycle, which uses atmospheric oxygen and liquid hydrogen from a standing start to above Mach 5 when it switches to onboard liquid oxygen, have shown the concept is thermodynamically feasible. The engine and innovative precooler at the heart of the cycle are ultimately aimed by Reaction at a single-stage-to-orbit (SSTO) launch vehicle dubbed Skylon.
However, while SSTO remains a long-range goal, Reaction has recrafted its ground demonstrator to reflect smaller-scale potential applications in the nearer term. AFRL, which is meanwhile working in parallel with Reaction under a cooperative research and development agreement, is for the first time outlining details of how SABRE might be used to support orbital launch missions when configured as part of a two-stage-to-orbit (TSTO) launch system. Working with Atlanta-based SpaceWorks Enterprises, AFRL has defined two initial next-generation launch system concepts: A partially reusable TSTO with a SABRE-powered booster and expendable rocket-powered second stage, and a second fully reusable option incorporating a SABRE-powered first stage and a rocket-powered upper stage. “We asked, ‘What’s a nearer-term approach to do access to space with this very interesting engine idea and precooling technology?’ and came up with this two-stage-to-orbit system,” says Barry Hellman of AFRL’s High-Speed Systems Division.
The first system is designed to place a 5,000-lb. payload into a 100-nm orbit with a 28.5-deg. inclination from Cape Canaveral AFS.. Two missions were also analyzed to determine performance to a sun-synchronous orbit at 378 nm flown from Vandenberg AFB, California, and a proposed UK spaceport site in Newquay, England.
The partially reusable concept is based on a twin-SABRE-powered winged booster. Measuring 150 ft. long, or about 4 ft. longer than a B-1B bomber, the vehicle would carry the rocket-powered second stage in a lower payload bay. “The notional concept of operations is like an aircraft with a horizontal takeoff and landing,” said Hellman at the American Institute of Aeronautics and Astronautics (AIAA) Space 2016 conference and exhibition in Long Beach, California, Sept. 13-16.
“The vehicle would accelerate to almost Mach 4.5 before transitioning to rocket mode, when it would pull up while still accelerating,” he said. “We carry the upper stage inside so it does not have to have a payload fairing or thermal protection system (TPS). That also means it has to stage at a very high altitude of over 260,000 ft. and a low dynamic pressure of about 0.8 psf. It then boosts away to orbit while the vehicle turns away and returns.” Staging would occur at about Mach 8 before the vehicle begins a gliding turn toward the launch site and briefly restarts the engines in air-breathing mode for additional boostback.
“We assumed we would have conformal hydrogen tanks and that would be another technology challenge that would have to be solved to make this design work,” Hellman said. By placing the payload underneath, no large cranes are needed to load the vehicle, and “when we get to staging, we use gravity and the payload just falls away,” he added. Hellman conceded, however, that payload bay door design will require special consideration for the TPS to handle reentry.
The vehicle’s propellant mass fraction (mass of propellant divided by the weight of the whole stage apart from the payload) “is about 0.43, and that is unheard of for access to space systems,” said Hellman. “That is what an air-breathing engine allows you to have. The bottom line is, the vehicle can make the mission with extremely low propellant-mass fractions.”
The second, fully reusable option consists of a 190-ft.-long scaled-up variant of the smaller booster and a reusable upper-stage booster. Designed to carry a 20,000-lb. payload to orbit, the 115-ft.-span booster and upper stage would collectively weigh about 1.3 million lb. at takeoff. The system would launch horizontally, and both stages would return for a horizontal landing. After deploying its payload, the upper stage would continue around the world and, with the cross-range capability of its 40-ft.-span, X-37B-like wing, recover to the launch site.
For the immediate future, the Air Force continues to focus on further evaluation of the precooler. “That is the biggest interest we have right now at AFRL,” Hellman said. “We have been looking at trying to get the funding to test the heat exchanger at higher temperatures, simulating conditions behind the inlet at Mach 3.5-5. It’s a very fascinating technology that has a lot of senior Defense Department and NASA officials excited. We are moving along slowly, though hopefully we will make more progress in the next few years.”
This has some information about the kind of engine that they are going to develop as a demonstrator (JSF-sized apparently)
Reaction Engines Refines Hypersonic Engine Demonstrator Plan | Technology content from Aviation Week
Reaction Engines Refines Hypersonic Engine Demonstrator Plan | Technology content from Aviation Week
The original Skylon built for the 1951 Festival of Britain was partly built by a firm in Hereford, Painter Brothers I think they also built electricity pylons. There was talk of erecting a similar Skylon at a proposed enterprise zone in the City.
Festival of Britain Skylon 'inspiration' behind design - BBC News
Just thought you might be interested having seen the earlier posts about the original.
Festival of Britain Skylon 'inspiration' behind design - BBC News
Just thought you might be interested having seen the earlier posts about the original.
