Had the UK only invested more generously in this earlier
Instead of bailing out banks and the financial ponzi moneylenders. Here's a way to leave a lasting impact on science, engineering and technology.
God, I feel like a BBC commentard sometimes!
The European Space Agency (ESA) has chipped in €1m to study the viability of the Skylon spaceplane concept - a radical single stage to orbit (SSTO) vehicle whose motors use "a synthesis of elements from rocket and gas turbine technology". Artist's representation of the Skylon. Pic: Reaction Engines The Skylon According to …
"Instead of bailing out banks and the financial ponzi moneylenders. Here's a way to leave a lasting impact on science, engineering and technology."
Well has you bothered to read the press release you'd know the money comes from ESA, not the BNSA.
It's a charming idea but the REL core staff had plenty of that when they were part of the UK launcher industry and Concorde.
They don't want to be a government project, with the "men from the ministry" always sniffing round and foisting their agendas on the programme.
This money is about starting to firm up the whole business case and hardware story IE Skylon, the Upper Stage to tranfer comm sats to GEO (recommended by the ESA fasability study) and the nuts and bolts of a serious piece of concrete for the takoffs (Skylons burn so much propellant it's been stated they can land on grass after a successful orbital delivery).
BTW Skylon is high risk in a way that, say, HS2 simply is not.
It is also high return.
It is good that it's getting cheaper and more convenient to put satellites in orbit.
The one doubt I have is that sometimes people involved in spacey type stuff seem to imply that there really isn't that much room out there and we are already starting to jam up orbital space with random junk. Is that actually going to be a problem with more and more delivery systems available?
A fair proportion of "space junk" exists because:
a) all of our delivery methods leave a fair amount of waste up there as part of the launch - a reusable system like this wouldn't do that
b) it's too expensive to clean up after ourselves - this could potentially change all that
Skylon pretty much is HOTOL, or at least it's spiritual successor - from the wiki article you linked:
In 1989, HOTOL co-creator Alan Bond formed Reaction Engines Limited (REL) which has since been working on the Skylon vehicle intended to solve the problems of HOTOL.
Has anyone noticed the similarity in shape between this and the spaceships in the 1950's classic science fiction film "When Worlds Collide" (and films of similar ilk).
Whenever I see pictures of this thing, I have flashbacks to when I saw the film as a five-year-old on TV, as the people desperately raced to escape planet Earth as imminent doom threatened :)
"Has anyone noticed the similarity in shape between this and the spaceships in the 1950's classic science fiction film "When Worlds Collide" (and films of similar ilk)."
Well strictly it resembles the AVRO 730 M3 reconnaissance bomber designed in the mid 1950s but cancelled by that rampant
cockhoud idiot Duncan Sandys. Engines on tip pods and IIRC the forward canard.
However most people go for the SR71, but the engines are mid wing and the canted twin tails.
They're, erh, unforeseen at the moment
Although Alan Bond has indicated that they taking another look at the heat exchanger mfg technology.
This was too expensive for F1 teams to use, despite the much smaller size radiators that would result (there's a lot of stuff that needs cooling on an F1 car. Much more so than your civilian motor).
He estimates they can cut the cost 5-10x.
For a rather pedestrian idea this would give a domestic GCH boiler about the size of a VHS video cassette.
Beyond that who would benefit from a very compact high efficiency heat transfer system?
Better than a Peltier you mean?
AFAIk the conversion efficiency (electrical power in to energy you can remove from the load) is <10%.
That's rubbish by most standards. They are handy for compactness and no moving parts (including a collant fluid if you have the power system to sustain them.
...the B-70 Valkyrie and Skylon's spiritual father, the SR-71...
I don't know where you get your history from, but I'm guessing that it's somewhere west of the Atlantic?
The Skylon (and its 'predecessor', HOTOL, are developments in air-breathing hybrid jet/rocket technology.
The B-70 and, to a lesser extent, the SR-71 are fast top-of-atmosphere jets using wave-rider technology. Quite a different thing. Wave-rider technology was invented by Terence Nonweiler, of Belfast University and later St Andrews. Another Brit.
"I don't know where you get your history from, but I'm guessing that it's somewhere west of the Atlantic?"
"The B-70 and, to a lesser extent, the SR-71 are fast top-of-atmosphere jets using wave-rider technology. Quite a different thing. Wave-rider technology was invented by Terence Nonweiler, of Belfast University and later St Andrews. Another Brit."
Sorry but AFAIK the SR71 used fairly conventional aerodynamics with the shock wave forming ahead of the wing (the sweep angle gives the actual maximum speed based on supersonic theory).
The XB70 used an idea developed by a Dr Eggers of NACA (at the time) he called "compression lift," but I suspect it's certainly moving into waverider territory.
...The ultimate aim is to make the Skylon system truly 100 per cent reusable. Italy's Thales Alenia Space (TAS) is mulling the secondary propulsion unit, and the hope is that this will, after delivering its satellite, make its way back to the spaceplane for return to base. ...
The secondary propulsion unit, if it's a rocket, will need to impart a load of extra energy to the payload. That energy will ALL have to be bled off in some way if the rocket is to return to the Skylon. In other words, you will need twice the impulse power.
Of course, if the Skylon SHOT the payload into a higher orbit, the reaction force would slow the Skylon down, and assist it to re-enter. That seems to me to be a much better use of the energy budget...
The Skylon would be suborbital, dropping off the transfer craft and then descending back to Earth of its own accord.
The transfer craft then burns to put the sat into the proper orbit.
To recover the transfer craft, wait until the next Skylon launch and play swopsies - transfer B is launched, and transfer A is recovered around apogee.
The delta-v needed for that isn't too bad - though the timing is well beyond my meagre Kerbal Space Program abilities!
The only teensy problem with that is that the article _explicitly_ mentions the aircraft being propelled to mach 25, which happens to be the exact orbital velocity for a full low earth orbit - not suborbital stuff. Granted, I'm all ears about where this thing keeps its reentry heat shield.
So it does, I'd got that confused with the Mach 5.5 bit.
That makes the re-use of the transfer tug considerably easier as it could be retrieved in the same mission, assuming the Skylon can stay on-orbit for long enough.
They intend to use the aeroshell itself as the heatshield, coupled with refrigeration using the last bit of cryogenic hydrogen.
While I certainly hope this all works, I do have a problem with the layout of the vehicle. Engines on the ends of the wings present some interesting structural and aerodynamic problems. First, the wing has to be stronger, and is going to be quite complicated with all the fuel lines, engine control systems, etc., running through it. More important is this - in this configuration, an engine-out is going to make a frisbee out of the vehicle, there isn't enough rudder or vectorable thrust available to keep going straight.
The engines really need to be mounted closer together, on the tail, think DC-9 or Lear Jet, and there needs to be some way to maintain directional stability in yaw despite the VERY asymmetrical thrust resulting from an engine-out event. Remember that the higher the performance and power output, the closer you are to the bleeding edge of technology. In this device, an engine-out situation is likely to be catastrophic.
Make the engines work, redesign the airframe, and THEN try it.
The engines become the heaviest part of the craft very quickly after launch, and by the time it's coming in for landing the fuselage is an empty tube.
Unless the engines are in the middle it's going to be ungodly unstable, likely impossible to control once back in atmosphere.
I'll take "screwed if engine flames out" over "screwed on every approach"
Also, if an engine flames out it may still be possible to safely abort and rescue the craft and payload, if it's going fast enough.
"The engines become the heaviest part of the craft very quickly after launch, and by the time it's coming in for landing the fuselage is an empty tube."
That engines-at-the back was one of the things that killed HOTOL. SOP for rockets but they realizes once you put wings on the structure the whole game changes. Realizing that putting the engines in the middle (with the payload pay in fact) were key features in turning HOTOL into Skylon.
Engines-at-the back at the back is also why no human pilot could directly fly the Shuttle.
Actually Skylon is designed to be statically stable. That's important because like Shuttle it will make a glide landing. Even REL could not come up with a way to do a powered landing, although given the craft will be at least 78% lighter on landing (more given a successful payload deployment) it should not be far off carrying enough LH2 for a 2nd pass.
Thanks for mentioning that. If the weight distribution is like a dumbbell, this is said to be "having a high polar moment of rotation", which means that once spinning - frisbee style - it is going to be almost impossible to stop.
This means the craft as shown in the artist's renderings has TWO major problems.
1) Huge asymmetrical thrust in an engine-out event, instant frisbee (yaw) and uncorrectable by any aerodynamic means (i.e instant disaster). While there will need to be attitude thrusters for out-of-atmosphere pitch, roll, and yaw changes, they won't be able to compensate for a main engine failure, and that tiny little vertical stabilizer/rudder is far too inadequate even at lower altitudes.
These are very powerful engines, and if one of them fails, the remaining engine's thrust at the end of a long arm is going to whip the craft around instantly and very vigorously, so yes, we're all going to die. Relax, it will be quick. Very quick.
2) Engines at the rear, as in DC-9 and Lear might result in an aft CG at zero fuel, and I do remember that most aircraft are not "empty tubes" but are full of people and things so the CG doesn't shift drastically - but in this case, if most of the fuselage is fuel tank, the aft CG will be a problem.
Lets put the engines close together, mounted near the CG of the aircraft, probably over (Honda jet) or under (ME-262) the wings. We don't want them so close together that a failure in one will propagate to the other (as in TU-144 and B-70), but we do want them as close as possible to the longitudinal center line of the aircraft so we don't wind up with the asymmetrical thrust problem.
All aircraft are a collection of compromises flying in formation. This particular drawing seems to have been done by a publicist, any aeronautical engineer would reject this configuration in a heartbeat.
I do support this project and hope they are ultimately successful, but I doubt the final aircraft is going to look very much like the picture.
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