Author Topic: The Reaction Engines Skylon Master Thread (5)  (Read 441212 times)

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 6186
  • Everyplaceelse
  • Liked: 827
  • Likes Given: 5146
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1040 on: 12/09/2015 02:38 AM »
Umm... yes.
LVs are also the only transport systems I am aware of that expose their cargo to multiple g's of acceleration during most of the transport time and Skylon will be no exception to this, won't it?
Interesting choice of phrase since it neatly excludes all carrier landings and take offs. AFAIk the Grumman C2 Greyhound subjects it's payload (about 4 tonnes of passengers and cargo) to about 2.25g  for about 3 secs without any special design.
Quote
Also, all other transport systems I'm aware of tend to require you to surround your sensitive cargo with extensive packaging which is usually there to mitigate the effects of even much more benign transport conditions and from which the cargo is then carefully being unwrapped after shipment.
Except accleration is one of those things you can't shield the insides of the payload from, so packaging has limited use. OTOH cutting down the vibration and noise inside the payload bay can pay big dividends in payload survival.
Quote
So it occurs to me that Skylon will still look much more in common with traditional LVs than with traditional air transport if it comes to cargo interfaces.
As always with these questions it's a matter of how much Skylon resembles an ELV and how much it resembles an aircraft.

The simple answer is it resembles  an aircraft a lot more than Shuttle did and it's very unlike an ELV.

The shuttle mounting was very configurable - trunion mounts and keel points could be bolted between (almost?) any pair of ribs. The Skylon concept has a forward mounting position and a rear mounting position, in both cases the three trunion mount design will have a very clearly defined specification of what you can put in it.
I think that was more a problem than a strength. The mounting hardware in the different locations was unique, multiplying the number of simulation runs needed to see if a certain set of payloads would be OK, or if they would interact badly.
Quote from: https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36826.0;attach=1083478
One area of the SKYLON airframe that was refined as part of the S-ELSO Study was the payload interfaces.  There were two reasons for reconsidering at the interface design.  The first reason was that pre- study work by 42 Technology Limited suggested the previous design as defined in Issue 1 of the SKYLON Users’ Manual could be optimised to both reduce mass and reduce the load coupling.  This design goal of the interface only carrying the payload inertial loads was considered important as it was hoped that the need for coupled structure analysis of payload and launcher could be eliminated
They are a problem if one is trying to adopt a airline-like operational model.
True. IIRC Hemsell mentioned that CLA was a large (but hidden) cost of all LV operations, which just does not exist for other modes of transport.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1041 on: 12/09/2015 03:59 AM »
I think that was more a problem than a strength. The mounting hardware in the different locations was unique, multiplying the number of simulation runs needed to see if a certain set of payloads would be OK, or if they would interact badly.


No, the CLA only was twice per mission, which was standard.  Multiple runs are not required. It is not a big deal as you say.

Also, Skylon having fixed attach points doesn't make CLA go away.  ELVs have fixed attach points.  Again, it is the structural stiffness of the payload and how it will interact with the carrier.

And yes, aircraft manufacturers have to do special analysis when carrying large unique cargo. 
like these:

http://i0.wp.com/www.defensemedianetwork.com/wp-content/uploads/2012/06/AN124-Condor-Heavy-Lift.jpg
http://www.chapman-freeborn.com/blog/wp-content/uploads/2013/12/AN-124-TRN-REC-Photo-3-December-2013.png



Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2543
  • Liked: 282
  • Likes Given: 39
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1042 on: 12/09/2015 04:10 AM »
Interesting choice of phrase since it neatly excludes all carrier landings and take offs. AFAIk the Grumman C2 Greyhound subjects it's payload (about 4 tonnes of passengers and cargo) to about 2.25g  for about 3 secs without any special design.
So you are saying you can carry any cargo in such a setup without special handling?
Plus, that's a high g-force for what? 3s?

Quote
Except accleration is one of those things you can't shield the insides of the payload from, so packaging has limited use.
Huh? Ever bought a washing machine?
Adding support packaging for fragile structures _within_ a device is an absolute standard procedure for anything somewhat susceptible to load issues.
A lot of things are also being shipped partly disassembled for the same reason.

It's an absolute standard procedure to have extensive processing for cargo to ship it through no so benign conditions yet it's something you can't easily do for most spacecraft.
Where you can (think shipping to ISS) it's of course done.

Quote
As always with these questions it's a matter of how much Skylon resembles an ELV and how much it resembles an aircraft.
Sure. So have you seen how spacecraft are shipped in an aircraft. Does that anyhow resemble how it would be shipped with Skylon?
This is how aircraft shipping of a spacecraft looks like:
http://www.satnews.com/images_upload/1323524237/Aspace_VA209_Arrival.jpg

Quote
The simple answer is it resembles  an aircraft a lot more than Shuttle did and it's very unlike an ELV.
OK, so it will be launched unfueled, partly assembled, in a container and with extensive packaging? And then it will be processed in orbit? Interesting, didn't know that.

« Last Edit: 12/09/2015 04:11 AM by pippin »

Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2543
  • Liked: 282
  • Likes Given: 39
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1043 on: 12/09/2015 11:15 AM »
Umm, you are aware my comments were not about ground handling but launch?
So you think spacecraft will be launched by Skylon packaged in a shipping container? Who's going to unpack them on orbit?

Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2543
  • Liked: 282
  • Likes Given: 39
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1044 on: 12/09/2015 06:28 PM »
No your comments were a bizarre strawman argument involving supporting the drum in a washing machine, that somehow didn't need supporting when being thrown around on top of a rocket.
Quite to the contrary.
My comment was giving a real-world, low-tech example to counter a bizarre claim that packaging would never support the internals of the shipped goods.

The point is that in "normal" shipping operations you _do_ package stuff up with all kind of special transport packaging and support to make sure it arrives in one piece.
That's the exact process that allows you to standardize on the shipping interfaces. You don't need any special support and CLA between your vehicle and the transport container because all of the sensitive load handling is being done through packaging which is being removed after shipment.

In cases where you can't do this you will find less standardized interfaces.

For a spacecraft you can't do that. You have high loads, vibrations and very little packaging because nobody can have an extended unpacking and reassembly process after delivery to orbit.

That is the reason why spacecraft have to be designed for the load environment they are seeing during launch and that factor is not going to be significantly different for Skylon than for traditional LVs.
Quite to the contrary: due to the horizontal takeoff you have even more complicated load situations because you have acceleration in several axis.


Quote
A shipping container is the standardised form factor for flying things in a plane. The three trunion mount is the standardised form factor for flying things in Skylon. The SPLC concept is intented to allow existing bus designs to be flown with little modification, by acting as an adaptor.
The shipping container (together with packaging and partial disassembly for shipping) is a way to move the problem of handling loads (coupled or not) away from the vehicle interface.
Unless you find a way to do the same for the spacecraft being launched with Skylon your operations will not resemble a standard shipping container.
And I don't see anything specific to the Skylon that would make this any easier than for any other LV.
« Last Edit: 12/09/2015 06:30 PM by pippin »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1045 on: 12/09/2015 09:17 PM »
It appears to have a dust cover. It appears to be mounted to the container by the same interface the launch vehicle will use. No signs of extensive packaging to me.


The launch vehicle interface is on the side during terrestrial shipping.  There are additional restraints on it that would have to be removed.   And there are additional covers on specific instruments. 

The spacecraft shown is one of the smaller GEOsats and not typical.
« Last Edit: 12/09/2015 09:18 PM by Jim »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1046 on: 12/09/2015 09:26 PM »

The LEO facility that straps them to a Fluyt to get them where they're going


Adding more operations adds more risk and costs.   Also, and how many LEO facilities are there going to be to service spacecraft to different orbits.   Also, there isn't going to be a LEO facility for quite some time if at all for that kind of support.

Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2543
  • Liked: 282
  • Likes Given: 39
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1047 on: 12/10/2015 01:02 AM »
The claim made was that packaging wouldn't be used to support  the internals of a payload (the context being of a launch vehicle payload that wouldn't be processed on orbit)
The claim was made that transport in Skylon is the same as other means of transport and that this would somehow be fundamentally different from how LVs work today. And that it would no longer be needed to redesign payloads for the LV environment because that's also not what you do with other means of transport.
Which doesn't hold because other means of transport usually expect the cargo to be in a condition that matches the transport environment and if that's not the case you solve it through packaging.

Since that's not an option here the payload WILL have to be able to withstand the launch conditions and that will indeed require a good deal of understanding of - among other things - coupled loads.

It happened with Shuttle around which a whole generation of payloads was designed. But Skylon won't have a law behind it mandating exclusivity so a spacecraft will have to match different vehicles. Few operators will rely on only one launch option, at least in the beginning.

Quote
But absolutely, the payload has to be designed to handle the load environment. For a washing machine being moved when not in use this involves removable spacers.

And that's what was debated and that I was answering to:

Seriously LV's are the only transport systems that often require the cargo to be redesigned multiple times because it could be shaken to bits, or cause it's carrier can be shaken to bits by the resonance it can excite back into the carrier vehicle.
I replied that this is exactly the case because in other transport systems you solve this problem through disassembly or packaging.
Where you can't do this, e.g. weapons on mil. aircraft the designer is usually well aware of the environment.





Quote
I don't expect it to visually look like a shipping container, I expect it to look like three trunions - but I expect the operations around it to resemble the operations around a shipping container, i.e. a well understood form factor with reasonable tolerences and defined load environment that is easy to handle in a routine and automated way.
But that's not really different to other LV operations, isn't it? I mean, part of the whole EELV activity was to define a standardized payload environment.


Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1048 on: 12/10/2015 01:43 AM »

the launch vehicle interface appears to be on the front-right side in the second picture - and it appears to me that that is where the spacecraft is being secured to the base. As the picture shows the cover being lowered I'm not sure there are any further restraints - there might be some on what would be the top when it is vertical, but I'd be surprised if that was designed to be load bearing.


There are further restraints and not just on LV interface.  One on end opposite of the LV interface and at the base of the container.

Been around many spacecraft and containers.

« Last Edit: 12/10/2015 01:46 AM by Jim »

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 6186
  • Everyplaceelse
  • Liked: 827
  • Likes Given: 5146
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1049 on: 12/10/2015 08:13 AM »
There are further restraints and not just on LV interface.  One on end opposite of the LV interface and at the base of the container.

Been around many spacecraft and containers.
Going back to an earlier post of yours.

I'm curious. Do people load payload propellant on the pad anymore?

I know OMS/RCS loading for Shuttle was mandated that way but AIUI the propellant systems for payloads are designed to eliminate any leak path from the tanks or vapors getting into the system to corrode it before launch with an actual barrier in the flow path that needs to be punctured by a pyrovalve to allow flow to start. [EDIT Likewise AIUI once the system is filled it's fill points are also sealed ]
 
Since Skylon has no hypergols in it's design I'd wonder just how "hazardous" would such an area be, although if people are using solids there's always a risk of unexpected ignition.

[EDIT I'm not sure how the SX Dragon system will work, give it has hypergols designed in and yet is designed for reuse. Sealing the fill caps always sound a pretty one-shot deal to me.  ]
« Last Edit: 12/10/2015 08:21 AM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1050 on: 12/10/2015 01:50 PM »

1.  I'm curious. Do people load payload propellant on the pad anymore?

2.  I know OMS/RCS loading for Shuttle was mandated that way but AIUI the propellant systems for payloads are designed to eliminate any leak path from the tanks or vapors getting into the system to corrode it before launch with an actual barrier in the flow path that needs to be punctured by a pyrovalve to allow flow to start. [EDIT Likewise AIUI once the system is filled it's fill points are also sealed ]
 
3. Since Skylon has no hypergols in it's design I'd wonder just how "hazardous" would such an area be, although if people are using solids there's always a risk of unexpected ignition.


1.  There are still a few and the upper stages load ACS propellant at the pad.

2.  It is not a puncture and not all are pyro.

3.  There are still leak paths and precautions are taken around fueled spacecraft no matter where they are.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 6186
  • Everyplaceelse
  • Liked: 827
  • Likes Given: 5146
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1051 on: 12/10/2015 07:26 PM »
1.  There are still a few and the upper stages load ACS propellant at the pad.

2.  It is not a puncture and not all are pyro.

3.  There are still leak paths and precautions are taken around fueled spacecraft no matter where they are.
Interesting. I'll note Skylon COP is built built around using the Skylon Upper Stage for BEO missions. It would probably have propellant loading done at the fueling apron along with the main tanks. IIRC it's ACS is designed to go with GH2/GO2 propellants. The problem would then be if a customer insisted on using a storable upper stage which was not delivered to the payload loading area fueled. I'd be very surprised at anyone wanting to do this.

Personally I'm glad some builders are moving away from pyro systems if possible. I understand they're reliability record is excellent but the shock signatures hammer everything in their immediate vicinity and depending on range rules you could end up installing them on the pad, which looks like a PITA. I still find it hard to believe Shuttle had 300 of them.  :(

However it's done it was my understanding that SOP for hypergolic systems is that there is a physical barrier between the tanks and the rest of the system, and possibly another one just upstream of the thrust chambers to prevent any sort of atmospheric attack during long term storage.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1052 on: 12/11/2015 12:08 AM »
1.  Interesting. I'll note Skylon COP is built built around using the Skylon Upper Stage for BEO missions. It would probably have propellant loading done at the fueling apron along with the main tanks. IIRC it's ACS is designed to go with GH2/GO2 propellants. The problem would then be if a customer insisted on using a storable upper stage which was not delivered to the payload loading area fueled. I'd be very surprised at anyone wanting to do this.

2. Personally I'm glad some builders are moving away from pyro systems if possible. I understand they're reliability record is excellent but the shock signatures hammer everything in their immediate vicinity and depending on range rules you could end up installing them on the pad, which looks like a PITA. I still find it hard to believe Shuttle had 300 of them.  :(

3.  However it's done it was my understanding that SOP for hypergolic systems is that there is a physical barrier between the tanks and the rest of the system, and possibly another one just upstream of the thrust chambers to prevent any sort of atmospheric attack during long term storage.

1.  It's the spacecraft with all the hyperbolas

2. Spacecraft still use a lot of them and the range doesn't require them to installed at the pad.  Don't know where you got that info.

3.  Yes,they are called valves.
« Last Edit: 12/11/2015 12:10 AM by Jim »

Offline Prober

  • Senior Member
  • *****
  • Posts: 10313
  • Save the spin....I'm keeping you honest!
  • Nevada
  • Liked: 700
  • Likes Given: 728
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1053 on: 12/12/2015 04:27 PM »
It seems to me that there could be a chance for REL to develop something which would not be economically worthwhile  if done by themselves but might be militarily worthwhile to the USAF.

How could one turn up one's nose at a chance to try out some aspects of Skylon/Sabre without needing to go directly to a $10 billion SSTO?  It could be a godsend.

That might control what aspects the engine demonstrator has to be most realistic about, how much money has to be spent on it and where.

That's my view why turn down money to develop technology that may eventually help you achieve your commercial aims.

My only fear is the USAF 'locking up' some vital technology for their use only.

think contrarian....who says the USAF doesn't have this technology ? Maybe the USAF needs a way to bring the tech out to the public without compromising the program.

2017 - Everything Old is New Again.
I have not failed. I've just found 10,000 ways that won't work. ~ by Thomas Alva Edison

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 6186
  • Everyplaceelse
  • Liked: 827
  • Likes Given: 5146
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1054 on: 12/12/2015 05:36 PM »
1.  It's the spacecraft with all the hyperbolas
That doesn't make sense. Can you explain it further?
Quote
2. Spacecraft still use a lot of them and the range doesn't require them to installed at the pad.  Don't know where you got that info.
Mostly thinking of the Shuttle launch procedure. I just remembered Ariane does not mandate this and I guess outside of NASA it's not that common.
Quote
3.  Yes,they are called valves.
I was unclear. I meant a solid fixed metal barrier in the fuel system.  Then again I may just be thinking of the system on the Lance missile, which needed storage times in years.
« Last Edit: 12/12/2015 05:39 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 6186
  • Everyplaceelse
  • Liked: 827
  • Likes Given: 5146
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1055 on: 12/12/2015 05:47 PM »
think contrarian....who says the USAF doesn't have this technology ? Maybe the USAF needs a way to bring the tech out to the public without compromising the program.

What a very special view of the world you do have.

This is not physics, it's engineering.  Anyone could have most of this technology if they were willing to spend the time and money (and by USAF the money was tiny) to develop it.

But nobody has and the USAF and spent billions on the X30 programme instead, which was 3x bigger han REL's entire projected next phase budget and delivered nothing in return IE yet another SCRamjet engine attempt.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Prober

  • Senior Member
  • *****
  • Posts: 10313
  • Save the spin....I'm keeping you honest!
  • Nevada
  • Liked: 700
  • Likes Given: 728
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1056 on: 12/12/2015 07:24 PM »
think contrarian....who says the USAF doesn't have this technology ? Maybe the USAF needs a way to bring the tech out to the public without compromising the program.

What a very special view of the world you do have.

This is not physics, it's engineering.  Anyone could have most of this technology if they were willing to spend the time and money (and by USAF the money was tiny) to develop it.

But nobody has and the USAF and spent billions on the X30 programme instead, which was 3x bigger han REL's entire projected next phase budget and delivered nothing in return IE yet another SCRamjet engine attempt.

as someone said earlier in the thread this is 1960's stuff, I agree.

take the "PDE"; some years ago I walked outside my home looked in the sky because I saw an unusual con trail.  It was unusual because it looked like donuts dropping from the sky then dissipating.  Yes, its about engineering hence my beliefs.
2017 - Everything Old is New Again.
I have not failed. I've just found 10,000 ways that won't work. ~ by Thomas Alva Edison

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1057 on: 12/13/2015 04:24 PM »
1.  It's the spacecraft with all the hyperbolas
That doesn't make sense. Can you explain it further?

2.  Mostly thinking of the Shuttle launch procedure. I just remembered Ariane does not mandate this and I guess outside of NASA it's not that common.


1.Hypergols.  Autocorrect error

2.  Wasn't applicable to the shuttle either.  There even was pyros in the Spacehab module and they were installed for months.   You are getting pyros mixed up with safe and arm devices which are used on solid motors.  But still it wasn't the installation, it was the activation that had to be done at the pad
« Last Edit: 12/13/2015 04:30 PM by Jim »

Offline Hanelyp

  • Full Member
  • ***
  • Posts: 369
  • Liked: 64
  • Likes Given: 252
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1058 on: 12/13/2015 08:56 PM »
One point of the Skylon concept, as I understand it, is avoidance of hypergols and other similarly difficult fluids.  Not that liquid hydrogen is easy, but it isn't prone to the same chemical reactions in storage or if small quantities leak around the plumbing.

Whether installation or activation, individual manual work on pyrotechnics is bad for quick and affordable launch.  On that point an electro-mechanical release that doesn't need personal attention for each launch has a great advantage.

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 31349
  • Cape Canaveral Spaceport
  • Liked: 9628
  • Likes Given: 299
Re: The Reaction Engines Skylon Master Thread (5)
« Reply #1059 on: 12/13/2015 09:11 PM »
1.  One point of the Skylon concept, as I understand it, is avoidance of hypergols and other similarly difficult fluids. 
2.  Whether installation or activation, individual manual work on pyrotechnics is bad for quick and affordable launch.  On that point an electro-mechanical release that doesn't need personal attention for each launch has a great advantage.

1.  Payloads can't avoid them

2.  Mechanical does have the same reliability.

Tags: