HOTOL/Skylon

[pmn1]

From what i've read, one of the reasons for the change in layout between HOTOL and Skylon was stability during flight.

If when proposed, HOTOL had the Skylon layout, what kind of performance do you think could be expected from using RB545 engines rather than Sabre engines - assuming Sabre engines are not possible in the early 80's?

 

[annodomini2]

The RB545 is classified, so no information is available to make a comparison.

The main suposed theoretical difference is the SABRE engines ability to gather oxidiser during flight, allowing for a lower take off weight, increasing the mass fraction or relative ISP.

 

[Boris_Badenov]

This technology can fundamentally change the human race. If a company can validate this as SSTO we will have a functioning colony on Mars within 20 years & Solar Power Satellites in 25.

 

[vulture4]

The people who've kept this concept alive all these years have done a fantastic job; the design has evolved considerably since HOTOL. Too bad NASA isn't interested in really modern technology, even as a design partner. Whether the UK is interested enough to give it a real chance we will have to see, but hopefully they will. The idea is brilliant, but since nothing similar has ever flown it will need extensive design study and, realistically, a prototype flight before anyone can even say whether it really works. Hopefully the UK space enthusiasts will push for sustained support this time around.

 

[kelvinzero]

I mentioned this in another thread, but I wonder why they dont aim lower? This skylon thing sounds like it is pretty much replace the shuttle using much less proven technology. A worthy goal but who is buying right now?

Two smaller goals could be an engine for a suborbital vehicle, and/or a totally reusable first stage of a two stage launcher of smallish payloads.

I would just like to see this move beyond the powerpoint stage to a functional engine, even if the function isnt quite as extravagant as Skylon.

 

[annodomini2]

I mentioned this in another thread, but I wonder why they dont aim lower? This skylon thing sounds like it is pretty much replace the shuttle using much less proven technology. A worthy goal but who is buying right now?

Two smaller goals could be an engine for a suborbital vehicle, and/or a totally reusable first stage of a two stage launcher of smallish payloads.

I would just like to see this move beyond the powerpoint stage to a functional engine, even if the function isnt quite as extravagant as Skylon.

Apparently they are looking at using the inlet cooling with a jet engine for a hypersonic passenger plane for ESA

The problems they have faced are a distinct lack of funding, which is why the program has/is taking so long.

The main revolutions in the system are obviously the engines, and also the thermal protection system. But the rest should be based on fairly conventional tech.

 

[kelvinzero]

I guess you mean this one.

http://www.reactionengines.co.uk/lapcat.html

cool

 

[pmn1]

From what i've read, one of the reasons for the change in layout between HOTOL and Skylon was stability during flight.

If when proposed, HOTOL had the Skylon layout, what kind of performance do you think could be expected from using RB545 engines rather than Sabre engines - assuming Sabre engines are not possible in the early 80's?

Got this back from Reaction Engines

The Skylon Configuration would have helped the HOTOL performance but I cannot be sure by how much, the new Sabre engine and structure concept both improved the performance probably more than the improved layout. However let me have a guess - the main impact of the configuration change would be to reduce the control surfaces and their hydraulics mass which would mean that HOTOL could get back to its orginal target payload of 7 tonnes.

 

[j05h]

vapourware.

These guys have been promising "Real Soon Now" one of these vehicles for almost 25 years! C'mon, where's the test article?

 

[kelvinzero]

vapourware.

These guys have been promising "Real Soon Now" one of these vehicles for almost 25 years! C'mon, where's the test article?

I thought it was more a matter of them making big claims about what would be possible if they had big funding. Surely they havent been claiming an actual product is imminent without funding.

 

[emudude]

Just became aware of this thread, so I thought I would re-post something on Skylon here:



Wow! I'm surprised that I haven't heard of this before...coupled with all the research going into artificial photosynthesis, nano-slicing of water molecules to create hydrogen and oxygen, etc...this Skylon concept really could be a breakthrough ...once we have the problem of launch expenses licked, we pretty much have it made in terms of public accessibility to space. Next step after that is to move industry up there like Russia wants to with their orbital construction yard for creating space vehicles too large to launch from earth.

Interesting Observation: A typical small cruise ship weighs about 20k tonnes, which translates into 1834 launches of a Skylon vehicle...the proposal for a 10 billion investment in a Skylon program involves a 'small fleet' of the vehicles...with one craft being able to launch every two days, a cruise ship's worth of materials could be brought into orbit in 2.51 years with one vehicle, and 229.25 days (about 63% of a year) with four vehicles . As well, a single launch of one of these vehicles can include a 60 person crew module in place of the 12 tonne payload module. Anyone else want to go on a cruise around the moon in about 20 years?

 

[Maitri982]

We have to remain highly skeptical about this concept. they have been in business since 1989 and have not yet produced a single engine to test these theories. They are likely hit some issues with key parts of this radical engine design.

Of course, i would like to think that these issues would be solvable because a trip to space could then be in my future...but I think we are a long way from knowing one way or the other...

Cheers,
M

 

[Jazman1985]

"We have to remain highly skeptical about this concept. they have been in business since 1989 and have not yet produced a single engine to test these theories. They are likely hit some issues with key parts of this radical engine design."

Yeah, kind of disappointing. Hopefully their enthusiasm will spur some intermediate horizontally launched air breathing concepts that are a little less cutting edge.

 

[pmn1]

Interesting news in this month’s Spaceflight

The British spaceplane developer Reaction Engines celebrated its 20th anniversary in mid-August and revealed that it is planning to fly its Skylon spaceplane for the first time in 2018.

Also

Preliminary studies have begun to develop a larger version of the Skylon design. Skylon D1 will be capable of carrying a 25 percent larger payload into orbit than the current design. It will also be approximately 340 tonnes in weight at take off compared with the current 275 tonnes.

 

[MeteorWayne]

Interesting news in this month’s Spaceflight

The British spaceplane developer Reaction Engines celebrated its 20th anniversary in mid-August and revealed that it is planning to fly its Skylon spaceplane for the first time in 2018.

9 years from now? Wow, things are moving pretty slowly with this concept, eh?

 

[nimbus]

Considering how little support they seem to have.. They're also not building it themselves. They'll have (as planned now anyway) a big company like Airbus do that. 2018 seems like a pretty average development speed given the circumstances.

 

[pmn1]

If you are using a system that is at least partially air-breathing, and your launch site is not close to the equator, is there any advantage to flying a dog-leg flight path to make maximum use of the air-breathing part to get to an equitorial position before switching to on board oxygen?

 

[Jazman1985]

"If you are using a system that is at least partially air-breathing, and your launch site is not close to the equator, is there any advantage to flying a dog-leg flight path to make maximum use of the air-breathing part to get to an equitorial position before switching to on board oxygen?"

I would think being a SSTO, this idea would create a severe disadvantage, no need to unnecessarily increase your dry mass ratio. They would most likely just take-off initially from the equator(or near to). It's only in air-launching that I could see that as an advantage.

 

[pmn1]

Shamelessly stolen from the 'Gordons Alive' Facebook site

Skylon Rocket Ajax...DIIIIVE....

http://www.reactionengines.co.uk/splm_movie_flash.html