Author Topic: The Reaction Engines Skylon Master Thread (1)  (Read 691989 times)

Offline Space OurSoul

  • Full Member
  • **
  • Posts: 256
  • Seattle, WA
  • Liked: 183
  • Likes Given: 50
Re: The Reaction Engines Skylon Master Thread
« Reply #660 on: 05/14/2012 06:00 pm »

if the fact that the undercarriage doors make the TPS engineering more difficult, would it be possible to avoid the issue by having skylon, or any winged reentry vehicle, re-enter upside down and then flip for low-speed flight and landing?

As well as violating the KISS principle, Skylon faces much greater engineering challenges than the undercarriage doors. It's challenging but doable. Remember the Shuttle doors worked without problem in over 100 flights.

Thanks. I had no real notion of how much of a challenge the gear doors are, but the fact that every winged reentry vehicle so far has reentered gear down should probably have told me something. :)
(not sure the idea violates KISS tho... Seems pretty KISS to have a contiguous TPS...) but anyway I'll go back to thinking about things I actually know something about. Thanks, guys.

-Jeff
A complete OurSoul

Offline Asteroza

  • Senior Member
  • *****
  • Posts: 2233
  • Liked: 791
  • Likes Given: 29
Re: The Reaction Engines Skylon Master Thread
« Reply #661 on: 05/15/2012 05:09 am »

if the fact that the undercarriage doors make the TPS engineering more difficult, would it be possible to avoid the issue by having skylon, or any winged reentry vehicle, re-enter upside down and then flip for low-speed flight and landing?


I don't see this as being functionally any harder the "swoop of death" maneuver for DC-Y style SSTO's. If anything, this is a simple roll. The major benefit would be an uninterrupted TPS surface (and substantial reduction of gear door failure as a Loss of Vehicle event), which could simplify attachment/removal/maintenance and keep it out of reach of runway FOD. The other major benefit, already stated, is simplified loading of the payload bay via simple drop pit with a scissor lift. Windows would functionally be in the same place.

Dealing with the rudder in a sane manner will be harder. Either have to go with a telescopic structure (not so good), perhaps a reduced rudder/strake with drag rudders/brakes outboard on the wings or SABRE engine nacelles (flying wings have demonstrated drag rudders pretty well). The other major issue is passenger orientation during launch and landing, versus reentry. You are potentially forced to have seats that can rotate 180 degrees in roll, or configure the entire interior of the passenger module to rotate. Unless you are fine with having your passengers hanging upsidedown during the reentry phase.

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 36144
  • Minnesota
  • Liked: 20486
  • Likes Given: 10631
Re: The Reaction Engines Skylon Master Thread
« Reply #662 on: 05/15/2012 03:01 pm »

if the fact that the undercarriage doors make the TPS engineering more difficult, would it be possible to avoid the issue by having skylon, or any winged reentry vehicle, re-enter upside down and then flip for low-speed flight and landing?


I don't see this as being functionally any harder the "swoop of death" maneuver for DC-Y style SSTO's. If anything, this is a simple roll. The major benefit would be an uninterrupted TPS surface (and substantial reduction of gear door failure as a Loss of Vehicle event), which could simplify attachment/removal/maintenance and keep it out of reach of runway FOD. The other major benefit, already stated, is simplified loading of the payload bay via simple drop pit with a scissor lift. Windows would functionally be in the same place.

Dealing with the rudder in a sane manner will be harder. Either have to go with a telescopic structure (not so good), perhaps a reduced rudder/strake with drag rudders/brakes outboard on the wings or SABRE engine nacelles (flying wings have demonstrated drag rudders pretty well). The other major issue is passenger orientation during launch and landing, versus reentry. You are potentially forced to have seats that can rotate 180 degrees in roll, or configure the entire interior of the passenger module to rotate. Unless you are fine with having your passengers hanging upsidedown during the reentry phase.
This is one of those times when you decide that it's worth a minor inconvenience (gear doors) to avoid a larger one (rotating the customers, dealing with the rudder/tail, etc).
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Space OurSoul

  • Full Member
  • **
  • Posts: 256
  • Seattle, WA
  • Liked: 183
  • Likes Given: 50
Re: The Reaction Engines Skylon Master Thread
« Reply #663 on: 05/15/2012 07:48 pm »

if the fact that the undercarriage doors make the TPS engineering more difficult, would it be possible to avoid the issue by having skylon, or any winged reentry vehicle, re-enter upside down and then flip for low-speed flight and landing?


I don't see this as being functionally any harder the "swoop of death" maneuver for DC-Y style SSTO's. If anything, this is a simple roll. The major benefit would be an uninterrupted TPS surface (and substantial reduction of gear door failure as a Loss of Vehicle event), which could simplify attachment/removal/maintenance and keep it out of reach of runway FOD. The other major benefit, already stated, is simplified loading of the payload bay via simple drop pit with a scissor lift. Windows would functionally be in the same place.

Dealing with the rudder in a sane manner will be harder. Either have to go with a telescopic structure (not so good), perhaps a reduced rudder/strake with drag rudders/brakes outboard on the wings or SABRE engine nacelles (flying wings have demonstrated drag rudders pretty well). The other major issue is passenger orientation during launch and landing, versus reentry. You are potentially forced to have seats that can rotate 180 degrees in roll, or configure the entire interior of the passenger module to rotate. Unless you are fine with having your passengers hanging upsidedown during the reentry phase.

Skylon's payload bay has a near-circular section... roll the whole crew module :-)

Like I said originally, the current Skylon configuration of control surfaces is not conducive to flip-re-enter, which is why I asked about alternative configurations thereof. I imagine doing away with the vertical stabilizer altogether, and placing vertical fins at the tips of the wings (on the engine nacelles), SR-71-style (or perhaps slightly inboard to reduce the moment around the wing roots, given Skylon's mass distribution). With proper management of CoG, these could then double as the struts for the main gear. Since these struts/fins would be doing double duty, perhaps there might even be weight savings.


I imagine the biggest issue is managing the structural loads from two opposite directions...


Fun to think about, anyway.

-Jeff


EDIT: Just realized that Asteroza was saying the same thing. That's what I get for replying at work when I'm distracted.
« Last Edit: 05/15/2012 08:49 pm by Space OurSoul »
A complete OurSoul

Offline Chilly

  • It's not rocket science
  • Member
  • Posts: 60
  • Central Ohio
  • Liked: 10
  • Likes Given: 10
Re: The Reaction Engines Skylon Master Thread
« Reply #664 on: 05/16/2012 02:44 pm »
Haven't had time to dig through every reply to this thread, but so far I've not seen any mention of a flight crew in regards to carrying passengers.

Call me old-fashioned but I think passengers willingly boarding a remotely-piloted vehicle is going to be a stretch. Perfecting the engines may end up being the easy part, particularly if regulators get involved with this question (which they are certain to do).

Much as I'd love to ride one someday, I can't see going without somebody up in the pointy end who knows what he's doing in case things go down the crapper.
« Last Edit: 05/16/2012 02:46 pm by Chilly »
Those who can't do, write.

Offline simonbp

  • Science Guy
  • Senior Member
  • *****
  • Posts: 7136
  • Liked: 310
  • Likes Given: 175
Re: The Reaction Engines Skylon Master Thread
« Reply #665 on: 05/16/2012 02:57 pm »
For the passenger flights, there would a single professional crew member to assist the crew and to deal with emergencies. CST and Dragon crew flights will likely do the same, and whatever they do will be the industry standard by the time Skylon flies.

Offline A_M_Swallow

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8906
  • South coast of England
  • Liked: 500
  • Likes Given: 223
Re: The Reaction Engines Skylon Master Thread
« Reply #666 on: 05/16/2012 04:14 pm »
Haven't had time to dig through every reply to this thread, but so far I've not seen any mention of a flight crew in regards to carrying passengers.
{snip}

The diagrams giving the layout of the Skylon's passenger cabin shows a pilot cabin.
http://www.reactionengines.co.uk/skylon_pax.html

I have not found where the stewardess sit.

Offline flymetothemoon

  • Full Member
  • **
  • Posts: 240
  • Liked: 40
  • Likes Given: 214
Re: Skylon
« Reply #667 on: 05/16/2012 05:12 pm »
I think they have always suggested there would be a "pilot" for manned flights, but if you listen to Mark Hempsell in lkm's excellent post above, he actually goes as far as to say that the pilot would really be more of an expert steward role, being the person versed in all procedures for normal situations and emergencies etc. Skylon doesn't need any actual "pilot".

P.S. Thanks for that link lkm. Never heard that before and it's a great interview.

http://www.thespaceshow.com/detail.asp?q=1203

Offline flymetothemoon

  • Full Member
  • **
  • Posts: 240
  • Liked: 40
  • Likes Given: 214
Re: The Reaction Engines Skylon Master Thread
« Reply #668 on: 05/16/2012 05:28 pm »
Much as I'd love to ride one someday, I can't see going without somebody up in the pointy end who knows what he's doing in case things go down the crapper.

...besides which there is definitely nowhere to sit up either "pointy" end. We can be really, really sure there will not be any glass to look out of in any part of the shell either - although there would certainly be some in the PAX cabin once the cargo bay doors are open. Would be tragic not to. I think it also goes without saying you would have external video piped in too.

Who is to say that this vehicle could actually be flown by a human operator anyway? At a minimum there would be an awful lot of fly by wire.

Ultimately I think we gotta accept that this is the 21st century. We need the machines to do the stuff for us if we want to do increasingly complex things :)
« Last Edit: 05/17/2012 12:05 am by flymetothemoon »

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 9855
  • Everyplaceelse
  • Liked: 2292
  • Likes Given: 12743
Re: The Reaction Engines Skylon Master Thread
« Reply #669 on: 05/17/2012 06:51 am »
Call me old-fashioned but I think passengers willingly boarding a remotely-piloted vehicle is going to be a stretch. Perfecting the engines may end up being the easy part, particularly if regulators get involved with this question (which they are certain to do).

AFAIK there are no plans for Skylon to be remote piloted. It's self guided by on board hardware. "Trajectory planning" has been estimated to cost 30% of the operations budget for a Shuttle launch. Hardware is much more capable than the 0.4 MIPS processors that Shuttle originally carried and eliminating the DiLILO procedure should eliminate a lot of staff at each customer.

Speaking of Shuttle you are aware that *every* takeoff was under *full* computer control with the flying controls switched off unless there was a serious emergency (that the crew were still alive at the end of)?

As for the landing the pilots *insisted* on going to manual claiming it would be too difficult to get the feel of the controls quickly if the 4 live computers (with 5th running the completely different BFS) all failed. Autoland software was available since (IIRC) flight 5 (which was roughly the end of the "test programme" where STS was certified for use. Sklyon's will have 200+ test flights first).

If you'd just spent 5 yrs learning to fly a mission you probably would too.

BTW Skylon is designed to fly *without* computers into it's landing configuration. Shuttle could not fly *without* computers (the scene in the movie "Space Cowboys" in the simulator with all computers and APUs dead IRL would mean everyone either bails out or dies).

The situation is likely to get more complicated if a landing at a regular airport is involved but that is the case for *all* remotely or autonomous guided aerial vehicles. REL have mentioned they have had some talks with the UK equivalent of the FAA and its European sibling organizations.

On a side note the windows on the Shuttle were a PITA to design, construct and inspect. However if it's just a passenger view that's needed a small one in with a camera behind it (with the panel contoured to the airframe, rather than flat) should be *fairly* straightforward.


[added] 3/4 of the way through June and no May update in sight.

Looks like we will not hear anything till July at the latest. I think their website comes under their marketing effort and they lost a person from there recently.

It should be interesting.
« Last Edit: 06/21/2012 01:32 pm by john smith 19 »
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022. Forward looking statements. T&C apply. "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap

Offline flymetothemoon

  • Full Member
  • **
  • Posts: 240
  • Liked: 40
  • Likes Given: 214
Re: The Reaction Engines Skylon Master Thread
« Reply #670 on: 06/25/2012 09:18 am »
[added] 3/4 of the way through June and no May update in sight.

Looks like we will not hear anything till July at the latest. I think their website comes under their marketing effort and they lost a person from there recently.

It should be interesting.


I spoke to their new comms lady over a week ago (who probably had better things to be doing than answering my email!) and she said look again in about a week, so an update is obviously in hand. Seems we might as well forgo the May update now and we'll just call it the June update!

She said they are absolutely flat out preparing for Farnborough (14th, 15th July) so we'll know what the story is then.
« Last Edit: 06/25/2012 04:36 pm by flymetothemoon »

Offline IRobot

  • Full Member
  • ****
  • Posts: 1312
  • Portugal & Germany
  • Liked: 310
  • Likes Given: 272
Re: The Reaction Engines Skylon Master Thread
« Reply #671 on: 06/25/2012 10:20 am »
Call me old-fashioned but I think passengers willingly boarding a remotely-piloted vehicle is going to be a stretch.
Roller-coasters. People actually pay extra for that feeling.

Offline Carreidas 160

  • Full Member
  • *
  • Posts: 170
  • Liked: 4
  • Likes Given: 0
Re: The Reaction Engines Skylon Master Thread
« Reply #672 on: 06/25/2012 07:26 pm »
Call me old-fashioned but I think passengers willingly boarding a remotely-piloted vehicle is going to be a stretch.
Roller-coasters. People actually pay extra for that feeling.

In both cases, if anything goes wrong, you'll end up at the bottom of a gravity well :)

Kidding aside, people routinely fly on planes, which basically are self-guided robots with _optional_ manual input.

Online Robotbeat

  • Senior Member
  • *****
  • Posts: 36144
  • Minnesota
  • Liked: 20486
  • Likes Given: 10631
Re: The Reaction Engines Skylon Master Thread
« Reply #673 on: 06/25/2012 08:21 pm »
Call me old-fashioned but I think passengers willingly boarding a remotely-piloted vehicle is going to be a stretch.
Roller-coasters. People actually pay extra for that feeling.
;D
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline simonbp

  • Science Guy
  • Senior Member
  • *****
  • Posts: 7136
  • Liked: 310
  • Likes Given: 175
Re: The Reaction Engines Skylon Master Thread
« Reply #674 on: 06/25/2012 09:55 pm »
And besides which, if Google et al. have their way, by the time Skylon flies a significant fraction of the cars on the road will be self-guided. Welcome to the future...

Anyways, I can't wait to see what they come up with for Farnborough...

Offline Chilly

  • It's not rocket science
  • Member
  • Posts: 60
  • Central Ohio
  • Liked: 10
  • Likes Given: 10
Re: The Reaction Engines Skylon Master Thread
« Reply #675 on: 06/29/2012 01:29 pm »
Call me old-fashioned but I think passengers willingly boarding a remotely-piloted vehicle is going to be a stretch.
Roller-coasters. People actually pay extra for that feeling.

In both cases, if anything goes wrong, you'll end up at the bottom of a gravity well :)

Kidding aside, people routinely fly on planes, which basically are self-guided robots with _optional_ manual input.

Yeah, but it's that "optional" part when you really want a proficient meat gyro up in the cockpit. Systems (both inside and outside the aircraft) fail. I'd much rather have someone onboard who might know how to deal with sudden problems than rely on a remote operator on the ground - or a collection of algorithms in a black box.

Assuming a Skylon-type vehicle is ever put into regular service, I can't see the various certifying authorities letting it take paying passengers without onboard crewmembers.

Lots of potentially very bad things can happen. Heck, someone should write a book about it!

http://www.amazon.com/Perigee-ebook/dp/B006PNL48I/ref=pd_rhf_gw_p_t_3

 ;D
Those who can't do, write.

Offline simonbp

  • Science Guy
  • Senior Member
  • *****
  • Posts: 7136
  • Liked: 310
  • Likes Given: 175
Re: The Reaction Engines Skylon Master Thread
« Reply #676 on: 06/29/2012 04:11 pm »
Assuming a Skylon-type vehicle is ever put into regular service, I can't see the various certifying authorities letting it take paying passengers without onboard crewmembers.

Again, by the time Skylon flies operationally (probably after 2020), driverless cars will quite common, and it's likely airline pilots will be legally restricted in the amount of actions they can perform (to prevent crashes due to pilot error).

Indeed, it's more likely that the FAA/etc will require extra certification for piloted aircraft to ensure the pilots can't easily make a fatal mistake.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 9855
  • Everyplaceelse
  • Liked: 2292
  • Likes Given: 12743
Re: The Reaction Engines Skylon Master Thread
« Reply #677 on: 06/29/2012 09:53 pm »


Yeah, but it's that "optional" part when you really want a proficient meat gyro up in the cockpit. Systems (both inside and outside the aircraft) fail. I'd much rather have someone onboard who might know how to deal with sudden problems than rely on a remote operator on the ground - or a collection of algorithms in a black box.

Sounds good in theory but where do you draw the line?

The Shuttle never flew without a highly skilled pilot but in reality the *whole* launch was under computer control. If anything happened during the SRB burn it was basically a case of hang on and if we're still alive at the end the GPC's will put us back in control.

Not forgetting the Shuttle is unstable *without* GPC software and power to controls (I'm not sure *any* human could generate the forces to overcome some of the aero loads involved). As for control rates imaging pulsed braking in a car to avoid skidding (if you don't have anti lock brakes) in 3 dimensions. Good luck with that.

The whole system has worked flawlessly on every launch.

So it *is* possible to build *unstable* aerospace planes that operate over the full 0-mach23-0 speed range under full computer control.

Skylon was designed to fly with *minimal* control surface movements. I'll guess it has "black zones" like all LV's but REL were very aware of STS and with their commercial aircraft background aimed for a system that works most of the time not by *constant* adjustment but because of the load balances between the control surfaces, fuselage and airflow.

STS would have failed if *any* of the key subsystems, the APUs (2 of 3 needed), the GPCs (1 of 5) and the aero actuators (inner port & starboard wings, tail and body flap multiples  IIRC) failed totally at *any* stage of the landing and takeoff (aero surfaces were active during STS launch)

It all worked but that that's a hell of a lot of hardware to carry.

The software development will be demanding but methods and processes exist to handle this. It's well within the SoA.

A bigger issue would be collision avoidance with uncooperative vehicles (things too small to carry an ATC transponder). This has been an issue with the idea of single person commuter helicopters (which the FAA and NASA seem to be pursuing).
MCT ITS BFR SS. The worlds first Methane fueled FFSC engined CFRP SS structure A380 sized aerospaceplane tail sitter capable of Earth & Mars atmospheric flight.First flight to Mars by end of 2022. Forward looking statements. T&C apply. "Extraordinary claims require extraordinary proof" R. Simberg."Competitve" means cheaper ¬cheap

Offline vulture4

  • Full Member
  • ****
  • Posts: 1098
  • Liked: 428
  • Likes Given: 92
Re: The Reaction Engines Skylon Master Thread
« Reply #678 on: 06/30/2012 02:10 am »
Any LV today should be capable of flying a full mission unmanned and do so 10 times before carrying people, with all the unanticipated problems corrected.

Offline DLR

  • Full Member
  • ****
  • Posts: 497
  • Liked: 18
  • Likes Given: 0
Re: The Reaction Engines Skylon Master Thread
« Reply #679 on: 06/30/2012 02:52 pm »
Skylon is projected to be reusable 200 times. While that is certainly a lot when compared to today's throw away rockets, it isn't when we compare it to high performance aircraft. Nobody would buy a 747 if it could only fly 200 times before it has to be retired. What are the reasons for this short service life? Is it just a conservative estimate or are there certain limitiations inherent to the design?

Also, how are the projected costs of a single Skylon flight calculated?

Tags:
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1