Author Topic: SNC building test schedule for Dream Chaser – Dryden Drop Tests upcoming  (Read 43013 times)

Offline Chris Bergin

Status update. Thanks again to SNC for being really helpful.

http://www.nasaspaceflight.com/2012/12/snc-building-schedule-dream-chaser-tests-upcoming/

This is also the first article since we revamped the news site. So if you're on twitter, facebook or any of that nonsense, click the "share" options and we'll see how that works out.

Offline Lee Jay

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I want to see this thing fly.  I mean, I REALLY want to see this thing fly!

Offline BrightLight

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I'm looking forward to the free-flight drop test video, maybe even a powered flight in '14 or '15

and BTW - Nice article Chris, is there any chance that SNC would discuss the economics of the DC as compared to CST-100 and Dragon, its a long shot but it is the nexus of the DC argument - its cheaper to fly a reusable craft.

Offline Chris Bergin

Thanks!

I highly doubt a commercial company would discuss anything to do with money, other than what they've been allocated by NASA. SpaceX give some loose prices for their launch services, but you can expect nothing else from these people.

And that's totally understandable.

Offline Longhorn John

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Great article. Love the continued baby orbiter references, and this....

"Dream Chaser has already flown, with the ETA enjoying its first taste of the outside like most youngsters – on the end of a safety harness."

Brilliant ;D

Offline yg1968

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Thanks!

I highly doubt a commercial company would discuss anything to do with money, other than what they've been allocated by NASA. SpaceX give some loose prices for their launch services, but you can expect nothing else from these people.

And that's totally understandable.

DC and others will usualy answer that they are trying to be cheaper than the Russians. But it is never clear on how many flights per year and how many passengers per flights are necessary for DC and others to be competitive with Soyuz.

My guess is that they are assuming that NASA will purchase 2 flights pear year with 7 passengers on each flight. NASA has already said that it only wants 4 astronauts per flight but I suppose that the 3 extra seats can either be filled with cargo or by spaceflight participants if NASA ever changes its mind on space tourism to the ISS. HEFT had estimated that each commercial crew flight would cost about $313M per flight. I suspect that it was more than an educated guess on their part. 
« Last Edit: 12/10/2012 05:26 PM by yg1968 »

Offline yg1968

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Good article. I like the new website too.

I have a question on this paragraph:

Quote
SNC added they are also determining the forward path for both the FTA and the third Dream Chaser – known to be the Orbital Vehicle (OV) – meaning there is no official word on whether the FTA will be the first Dream Chaser to fly a test flight in space, ahead of the OV which will be the Dream Chaser capable of carrying out commercial crew missions to the ISS.

Will SNC build the third (OV) DC even if they are not funded past the CCiCap base period or does the third (OV) DC depend on future funding from NASA?

« Last Edit: 12/10/2012 05:28 PM by yg1968 »

Offline Chris Bergin

Thanks John and YG.

I'm sure the OV is related to NASA funding continuing, at least the schedule to mid-2010s....but I'll ask them for scenarios in the event they lose out on the down-select.

Offline Star One

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Great article. Personally this is the one of the three commercial vehicles that catches my interest, no doubt because it is a shuttle type vehicle rather than a capsule. :)
« Last Edit: 12/10/2012 08:58 PM by Star One »

Offline Rocket Science

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Nice piece Chris! Let’s start to build up that excitement for the first drop test. Fly little bird fly... ;D
"The laws of physics are unforgiving"


Offline john smith 19

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I want to see this thing fly.  I mean, I REALLY want to see this thing fly!
Many people would. It is hands down the most radical aerospace vehicle with a potential to fly in the next 5 years.

Given the approach they've taken and the funds they've received I think their progress has been fantastic. Their gradual upgrading from structural test article to flight test has been a very clever use of limited funds.

The fact they are not a capsule and planning to fly on one of the worlds most reliable LV's would make the idea of "design diversity" a real fact.

At the same time I think we'd all like NASA to fund all 3 designs to completion but that has to be viewed as highly doubtful.

I suspect the fact that Boeing are Boeing and both the other competitors were given about 2x the funding of SNC will count against them.  :(

If funding for the OV does not go ahead I wonder if it would be possible for NASA to certify the design (and SNC's planned build process) for ISS docking if SNC could get the funding to build it?

This would remove a significant obstacle in allowing ISS access to DC and increase investor confidence that NASA was OK with the design, just not actually able to fund it.
"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 Lars_J

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Nice article! I am very excited to see this thing fly - in any shape.

I want to see this thing fly.  I mean, I REALLY want to see this thing fly!
Many people would. It is hands down the most radical aerospace vehicle with a potential to fly in the next 5 years.

What do you mean by "most radical"?
« Last Edit: 12/11/2012 12:04 AM by Lars_J »

Offline Todd Martin

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Great update on Dreamchaser.  I've always thought it was a shame that Enterprise was never upgraded from a flight test article (FTA) to an orbital vehicle (OV).  There's a wide range of possibilities as far as how close they adhere to a finished design with a FTA.  I would love to know whether the Dreamchaser FTA will be upgradeable to an OV.

Offline TomH

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I've always thought it was a shame that Enterprise was never upgraded from a flight test article (FTA) to an orbital vehicle (OV).

I always wanted to see that happen, and I thought it might following both Challenger then Columbia. Apparently, thought, every time they built a new orbiter, they found more and more ways to shave more weight. The FTA airframe was apparently too heavy to be worth conversion.

On the cost effectiveness issue, I would think a high flight rate would make the difference. This vehicle should be much more reliable as a reusable vehicle than STS was and her turn around time could become substantially shorter. The TPS issue is substantially less as top-mount on the LV. The highest number of reuses for a capsule that I can remember reading is 10, but I could see a DC being re-certified through 200 flights. Couple that with RTLS and no well-deck ship necessary for recovery, amortized costs over a high flight rate just seems to favor this vehicle.
« Last Edit: 12/11/2012 03:26 AM by TomH »

Offline Khadgars

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I've always thought it was a shame that Enterprise was never upgraded from a flight test article (FTA) to an orbital vehicle (OV).

I always wanted to see that happen, and I thought it might following both Challenger then Columbia. Apparently, thought, every time they built a new orbiter, they found more and more ways to shave more weight. The FTA airframe was apparently too heavy to be worth conversion.

On the cost effectiveness issue, I would think a high flight rate would make the difference. This vehicle should be much more reliable as a reusable vehicle than STS was and her turn around time could become substantially shorter. The TPS issue is substantially less as top-mount on the LV. The highest number of reuses for a capsule that I can remember reading is 10, but I could see a DC being re-certified through 200 flights. Couple that with RTLS and no well-deck ship necessary for recovery, amortized costs over a high flight rate just seems to favor this vehicle.

Hopefully thats true, their only shot I would think is to be able to beat SpaceX on cost?  But then the Atlas V is much more expensive than a Falcon 9

Offline joek

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On the cost effectiveness issue, I would think a high flight rate would make the difference. This vehicle should be much more reliable as a reusable vehicle than STS was and her turn around time could become substantially shorter. The TPS issue is substantially less as top-mount on the LV. The highest number of reuses for a capsule that I can remember reading is 10, but I could see a DC being re-certified through 200 flights. Couple that with RTLS and no well-deck ship necessary for recovery, amortized costs over a high flight rate just seems to favor this vehicle.

At what flight rate--say about 2/yr, which is what appears to be expected for CTS?  I don't see it until/unless there is much greater demand.

Offline Elmar Moelzer

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I always wanted to see that happen, and I thought it might following both Challenger then Columbia. Apparently, thought, every time they built a new orbiter, they found more and more ways to shave more weight. The FTA airframe was apparently too heavy to be worth conversion.

On the cost effectiveness issue, I would think a high flight rate would make the difference. This vehicle should be much more reliable as a reusable vehicle than STS was and her turn around time could become substantially shorter. The TPS issue is substantially less as top-mount on the LV. The highest number of reuses for a capsule that I can remember reading is 10, but I could see a DC being re-certified through 200 flights. Couple that with RTLS and no well-deck ship necessary for recovery, amortized costs over a high flight rate just seems to favor this vehicle.
IIRC, the DreamChaser will still have a turnaround time of 2 months between flights. That is mostly because of the TPS needed a lot of service time. This is IMHO the biggest problem with the concept of the DC, the shape requires a comples TPS like the shuttle's was and that means a lot of inspection work. That will raise the price of operating it.

Offline Lurker Steve

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I always wanted to see that happen, and I thought it might following both Challenger then Columbia. Apparently, thought, every time they built a new orbiter, they found more and more ways to shave more weight. The FTA airframe was apparently too heavy to be worth conversion.

On the cost effectiveness issue, I would think a high flight rate would make the difference. This vehicle should be much more reliable as a reusable vehicle than STS was and her turn around time could become substantially shorter. The TPS issue is substantially less as top-mount on the LV. The highest number of reuses for a capsule that I can remember reading is 10, but I could see a DC being re-certified through 200 flights. Couple that with RTLS and no well-deck ship necessary for recovery, amortized costs over a high flight rate just seems to favor this vehicle.
IIRC, the DreamChaser will still have a turnaround time of 2 months between flights. That is mostly because of the TPS needed a lot of service time. This is IMHO the biggest problem with the concept of the DC, the shape requires a comples TPS like the shuttle's was and that means a lot of inspection work. That will raise the price of operating it.

I thought I read that the TPS was easily replacable, since it was part of a lower shell that comes off in 1 piece. All they need to do is build up a supply of flight-ready TPS.

I doubt any vendor will need to re-fly the same vehicle in less than 2 months anyway.

Offline john smith 19

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What do you mean by "most radical"?

It's planned as a human rated crewed composite vessel lifting body using non-toxic RCS and hybrid LAS/OMS flying on an ELV without a fairing.
If it flies it would shift the current state of practice in materials (The ATK proposal was talking about a composite capsule), aerodynamics (no fairing launch. The X37b is a wing/body design, not an LB) and engine tech (it's a big hybrid but I'm not sure if they are staying with LOX/Ethanol for the RCS).

The Shuttle heritage TPS seems to be the least radical bit of the design.

For near future actual build and flying I'd call that lot a pretty radical collection.
« Last Edit: 12/11/2012 08:27 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 Elmar Moelzer

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I thought I read that the TPS was easily replacable, since it was part of a lower shell that comes off in 1 piece. All they need to do is build up a supply of flight-ready TPS.

I doubt any vendor will need to re-fly the same vehicle in less than 2 months anyway.


http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/

Quote from: article
But regardless of the nature of Dream Chaser’s landing, Sierra Nevada is currently looking at a two-month turn-around of the vehicle between flights to LEO.

In those two months, large-scale sections of the spaceplane’s Thermal Protection System tiles would be replaced if needed – with whole tiles being replaced (even if just for a scratch) instead of repaired, as was the case with Shuttle.

The problem with this is not the availability of the vehicle but the cost of servicing it. 2 months of work for highly specialized personell means a lot of cost, not to mention the materials for the TPS itself.
This will make it difficult for the DC to compete with the capsules.

Offline john smith 19

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The problem with this is not the availability of the vehicle but the cost of servicing it. 2 months of work for highly specialized personell means a lot of cost, not to mention the materials for the TPS itself.
This will make it difficult for the DC to compete with the capsules.
True. The figures for Shuttle TPS replacement costs were $12 000 m^2 for tiles and $3000 m^2 for blankets, But I'm not sure when those figures in the NASA TPSX database were last updated.

Note1 that SNC could use multi-skilled teams for whom tile testing/replacement was just one task they dealt with.

Note2 Carnegie Mellon outlined a plan to do robotic inspections of the Shuttle. With a clean sheet approach and a desire to design cost out of the support infrastructure from day 1 SNC could do something like that and use its test results to directly drive new tile mfg. Given some ares were consistently damaged on landing for the Shuttle pre-ordering replacements for those would also be a viable strategy to lower turnaround time.
"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 Chris Bergin

Slight update to the article, I've removed the White Knight 2 graphic showing Dream Chaser as that is now confirmed to be no longer an option.

Offline TomH

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Hopefully thats true, their only shot I would think is to be able to beat SpaceX on cost?  But then the Atlas V is much more expensive than a Falcon 9

They are starting out on AV. I don't believe they've ruled out using F9 as an LV later on.

Offline TomH

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Slight update to the article, I've removed the White Knight 2 graphic showing Dream Chaser as that is now confirmed to be no longer an option.

That's disappointing; that would have been a beautiful air drop (maybe even air launch test using the hybrid engines) to watch. Phooey.  :(

Offline Elmar Moelzer

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Slight update to the article, I've removed the White Knight 2 graphic showing Dream Chaser as that is now confirmed to be no longer an option.
Oh, why is that? Must have missed that.

Offline Lee Jay

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Slight update to the article, I've removed the White Knight 2 graphic showing Dream Chaser as that is now confirmed to be no longer an option.

That's disappointing; that would have been a beautiful air drop (maybe even air launch test using the hybrid engines) to watch. Phooey.  :(

This doesn't mean they aren't going to do this, it just means they aren't going to do it with that particular carrier aircraft.

Offline Lurker Steve

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Slight update to the article, I've removed the White Knight 2 graphic showing Dream Chaser as that is now confirmed to be no longer an option.

That's disappointing; that would have been a beautiful air drop (maybe even air launch test using the hybrid engines) to watch. Phooey.  :(

This doesn't mean they aren't going to do this, it just means they aren't going to do it with that particular carrier aircraft.

What other options do they have ?

Offline yg1968

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Would it be possible to use an Air-Crane helicopter again (as they did for the captive-carry test) or does it have to be an airplane?
« Last Edit: 12/13/2012 06:09 PM by yg1968 »

Offline Lurker Steve

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Can they get up to the altitude / flight speed they want with the Air Crane ?

Does NASA still have a B-52 that can be used as a carrier aircraft, or is the DreamChaser too big to fit under the wing ?

Offline Elmar Moelzer

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Would it be possible to use an Air-Crane helicopter again (as they did for the captive-carry test) or does it have to be an airplane?
I may be wrong, but there may be the need for more speed and altitude than this helicopter can provide.

Offline nlec

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Can they get up to the altitude / flight speed they want with the Air Crane ?

Does NASA still have a B-52 that can be used as a carrier aircraft, or is the DreamChaser too big to fit under the wing ?

I'm thinking, is it too late to bring the last SCA out of retirement to carry Dream Chaser? It looks like there is some precedent with Phantom Ray.

http://en.wikipedia.org/wiki/File:Shuttle_Carrier_Aircraft_-_Silhouettes.jpg
« Last Edit: 12/13/2012 07:02 PM by nlec »

Offline Jim

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I'm thinking, is it too late to bring the last SCA out of retirement to carry Dream Chaser? It looks like there is some precedent with Phantom Ray.


It was only used to transport the Phantom Ray, it wasn't dropped.

Offline BrightLight

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Using a flying B-52 might still be possible such as the plane that flew the X-51 (B-52, tail number 050), a pylon "extension" would probably be needed and one was built for the X-38. I don't know if that extension still exists as the aircraft it was used on was retired (Tail number 008). If that extension is available and SNC was able to use and modify it, then a B-52, in theory, can be used for the drop tests.

Offline Lars_J

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Won't DC be on the heavy side to be carried out on the wing by a B-52? Without the WK2, what good options are there for a (relatively) high speed drop tests?
« Last Edit: 12/13/2012 10:59 PM by Lars_J »

Online Ronsmytheiii

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Using a flying B-52 might still be possible such as the plane that flew the X-51 (B-52, tail number 050), a pylon "extension" would probably be needed and one was built for the X-38. I don't know if that extension still exists as the aircraft it was used on was retired (Tail number 008). If that extension is available and SNC was able to use and modify it, then a B-52, in theory, can be used for the drop tests.

NASA no longer has a b-52, and I doubt the AF would agree to let a strategic asset be taken out of service for a commercial company.

Maybe Stargazer could be modified?
« Last Edit: 12/13/2012 11:42 PM by Ronsmytheiii »

Offline A_M_Swallow

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Gliders are frequently towed.  If the Dream Chaser can take off on its wheels then a fast, high flying aircraft may be able to get it into the air.

Offline Elmar Moelzer

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Can anyone tell me why the WK is no longer an option for the DC drop tests? I must have missed that part.

Online Silmfeanor

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Can anyone tell me why the WK is no longer an option for the DC drop tests? I must have missed that part.

It's on L2 - get it to read it  ;)

Offline vt_hokie

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Gliders are frequently towed.  If the Dream Chaser can take off on its wheels then a fast, high flying aircraft may be able to get it into the air.

Yeah, gonna take more than a Piper Pawnee to tow that glider!

Offline LaunchedIn68

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Can anyone tell me why the WK is no longer an option for the DC drop tests? I must have missed that part.

Reportedly over concerns that use of the vehicle will delay flight testing of SpaceShipTwo. They also had concerns about potential damage to the carrier aircraft
"I want to build a spaceship, go to the moon, salvage all the junk that's up there, bring it back, sell it." - Harry Broderick

Offline Jason1701

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Can anyone tell me why the WK is no longer an option for the DC drop tests? I must have missed that part.

Reportedly over concerns that use of the vehicle will delay flight testing of SpaceShipTwo. They also had concerns about potential damage to the carrier aircraft

Could they possibly see DC as an airlaunched hybrid-powered competitor to SS2?

Offline Elmar Moelzer

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I dont quite get the concern about delaying SS2 testing. The SS2 tests are still very infrequent and I doubt that the WK2 will be used fully by them. I might be underestimating the amount of service hours it needs, though.
I would understand concerns about the DC being able to damage the WK2. That would however be in stark contrast about the versatility VG claimed for the WK2 in the beginning of the development (it was advertised as being useful for just this thing) of the WK2 SS2 system.
Still, with only one WK2 being currently operational, even a freak accident damaging it would indeed delay SS2 testing. So maybe that is their reasoning behind that?
 
Could they possibly see DC as an airlaunched hybrid-powered competitor to SS2?

IIRC, the suborbital version of the DC was not meant to be airlaunched, but would have launched vertically like the X33.
Last time I saw that was a long time ago though and it might have changed since then.
Anyway, this does sound like a plausible explanation to me. But then, I dont think that SNC would care much about flying the DC suborbitally, if they were selected for commercial crew. I also think that it would need some modifications for that (IIRC, I would have needed more of the same hybrid engines, but that might have changed as well). So not letting them do the drop tests might actually be counterproductive, since it would reduce SNCs chances for commercial crew and thus would make a suborbital DC more likely. Granted, this is massive speculation on my side and I may be wrong here (it is still fun to speculate though).

Offline Lee Jay

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Gliders are frequently towed.  If the Dream Chaser can take off on its wheels then a fast, high flying aircraft may be able to get it into the air.

Yeah, gonna take more than a Piper Pawnee to tow that glider!

DC has no front landing gear (just a skid) and a normal landing speed above 190 knots.  I'm not sure it could be towed given those particular attributes.

Offline Rocket Science

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Gliders are frequently towed.  If the Dream Chaser can take off on its wheels then a fast, high flying aircraft may be able to get it into the air.

Yeah, gonna take more than a Piper Pawnee to tow that glider!

DC has no front landing gear (just a skid) and a normal landing speed above 190 knots.  I'm not sure it could be towed given those particular attributes.
They could use a dolly under the skid that remains on the ground or replace the nose skid for a conventional gear for this test using air tow and ignite motors to gain altitude and airspeed. Of course they will need a retract mechanism. An aircraft like the C-17 could get the job done to air tow DC.
"The laws of physics are unforgiving"

Offline Prober

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Is this going to be a full size DC?

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 JAFO

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.
Anyone can do the job when things are going right. In this business we play for keeps.
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Offline Rocket Science

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.

Yup, If SNC was to go this way with air tow they would have to be sensitive to turbulence behind to tow aircraft. The L/D of the DC and aero properties being quite a bit different than the QF-106 it could be simmed and tested in a wind tunnel. Another is to see if DC can get out of ground effect on takeoff roll. You can imploy RATO bottles mounted along the sides to assist. It could even ground light the Hybrid motors and take off on its own then. If you want a fancy way to ensure launch you could build a “ski jump” ramp as is used on the British class aircraft carriers for the Harrier. Or you could ignite the motors after drop from SkyCrane and climb to test altitude and airspeed. Heck we did "zero length launch" in the 1950's. The point I am trying to make is that there are always alternatives if you are creative in you thinking...

http://aviationtrivia.blogspot.ca/2010/04/development-of-bae-sea-harrier-frs.html

http://upload.wikimedia.org/wikipedia/commons/thumb/d/de/YAV-8B_Harrier_testing_a_ski_jump.jpg/746px-YAV-8B_Harrier_testing_a_ski_jump.jpg


http://www.youtube.com/watch?feature=endscreen&v=oImq1glnOds&NR=1
« Last Edit: 12/15/2012 12:33 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline Elmar Moelzer

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.

The Kelly Eclipse was meant to have much larger wings than that. I dont think the DC is a good enough glider to be towed, but I may be wrong here.

Offline Rocket Science

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Recall that in December 1997-February 1998 NASA sucessfully towed a F-106 behind a C-141 in the Eclipse Project. http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-02-DFRC.html

May not be practical for DC since the loads on the structure would be different for a nose tow attachment than the top of the fuselage mount.


Trivial pursuit: one of the test pilots of the F-106 was Mark "Forger" Stuckey, now a pilot on SS2.

The Kelly Eclipse was meant to have much larger wings than that. I dont think the DC is a good enough glider to be towed, but I may be wrong here.
M2-F1 was towed behind a C-47 and a car (Pontiac) no problem. ;)

http://www.nasa.gov/topics/history/M2_F1.html

http://www.redorbit.com/news/space/1526597/the_m2f1_forefather_to_the_space_shuttle/
"The laws of physics are unforgiving"

Offline Elmar Moelzer

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Not sure how comparable this prototype is with the DC, but I guess towing might be an option after all (if they dont run into stability problems).

Offline Rocket Science

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Not sure how comparable this prototype is with the DC, but I guess towing might be an option after all (if they dont run into stability problems).
If you are curious about lifting bodies have a look at my thread here...

http://forum.nasaspaceflight.com/index.php?topic=29126.0
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Offline john smith 19

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If you are curious about lifting bodies have a look at my thread here...

http://forum.nasaspaceflight.com/index.php?topic=29126.0
The M1F2 was a plywood over welded metal tubing design mostly to demonstrate it could glide at all.

BTW I thought that DC is moving to "skids" or metal brushes rather than wheels. I'd guess the friction would be difficult for a rolling towed takeoff.

A high(ish) altitude drop with the hybrid rocket to get the rest of the altitude and speed needed seems the most plausible way to widen the envelope if WK2 is not available I think DC is small enough to be dropped out of a big carrier aircraft but that's a whole different area to explore.

Thanks for the zero length launch video. I would not have believed they ever managed it with a crewed vehicle, although I was aware some of the cruise missile designs of the 50s were baselined with it. 
"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 Rocket Science

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If you are curious about lifting bodies have a look at my thread here...

http://forum.nasaspaceflight.com/index.php?topic=29126.0
The M1F2 was a plywood over welded metal tubing design mostly to demonstrate it could glide at all.

BTW I thought that DC is moving to "skids" or metal brushes rather than wheels. I'd guess the friction would be difficult for a rolling towed takeoff.

A high(ish) altitude drop with the hybrid rocket to get the rest of the altitude and speed needed seems the most plausible way to widen the envelope if WK2 is not available I think DC is small enough to be dropped out of a big carrier aircraft but that's a whole different area to explore.

Thanks for the zero length launch video. I would not have believed they ever managed it with a crewed vehicle, although I was aware some of the cruise missile designs of the 50s were baselined with it. 
There is no cargo door large enough that I have found yet to release from... DC is using a skid for the nose gear for which they could use a dolly under. Or keep all the gear retracted and use a three wheeled dolly that could be dropped after takeoff, like was done with the Messerschmitt Me-163 Komet, (which used a two wheel one).  A rocket booster can even be mounted in a dolly and then the Hybrid motors could be ignited for climb out. Once again always possibilities...  I really see no showstoppers with this program...



« Last Edit: 12/16/2012 12:06 PM by Rocket Science »
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Offline mr. mark

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Looks like the Dreamchaser project is starting to hit some unexpected realities. Wonder how soon until the Stratolaunch lifter is ready? Several years away?

Offline Rocket Science

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Looks like the Dreamchaser project is starting to hit some unexpected realities. Wonder how soon until the Stratolaunch lifter is ready? Several years away?
DC will be on orbit before it if ever completed...
« Last Edit: 12/16/2012 12:04 PM by Rocket Science »
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Offline mr. mark

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In orbit? Looks like they are having trouble just getting Dreamchaser off the ground for this droptest. Might be the Spruce Goose of spaceflight. As for a rocket assisted first test flight, I would say that is very unrealistic with a lifting body design.

Offline Rocket Science

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In orbit? Looks like they are having trouble just getting Dreamchaser off the ground for this droptest. Might be the Spruce Goose of spaceflight. As for a rocket assisted first test flight, I would say that is very unrealistic with a lifting body design.
It is not a technical or design problem with DC... The problem is with Scaled, ask them for motives...
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Offline QuantumG

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It is not a technical or design problem with DC... The problem is with Scaled, ask them for motives...

What's Scaled got to do with it?

VG owns WK2.
Non-commercial spaceflight and filicide  http://tylervigen.com/view_correlation?id=185

Offline Rocket Science

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It is not a technical or design problem with DC... The problem is with Scaled, ask them for motives...

What's Scaled got to do with it?

VG owns WK2.

Did not Northrop Grumman buy scaled? If you say VG owns WK2 in particular, I’ll take you at word Trent...

Edit to add: I just checked this, not that I don't trust you... ;D

http://www.militaryaerospace.com/articles/2012/10/virgin-scaled.html
http://www.parabolicarc.com/2012/10/06/virgin-galactic-takes-full-ownership-of-the-spaceship-company/
http://www.businesswire.com/news/home/20121005005907/en/Virgin-Galactic-Acquires-Full-Ownership-Spaceship-Company

Me smells Sir Richard me thinks... ::)
« Last Edit: 12/16/2012 01:33 PM by Rocket Science »
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Offline Rocket Science

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If one wanted to perform an air drop extraction of DC from a cargo plane you would need folding fins as was done to the X-38/CRV for stowing in the shuttle cargo bay.  They would deploy after extraction. That would be an expensive and time consuming redesign.
Another option from rocket power from air drop from SkyCrane or air tow would to employ turbojets on pods as was done on the Buran Analog or fly it off the ground, this was considered and built for the X-24A as the SV-5J (internal J60 jet engine) program...

Once again always alternatives...

http://www.spaceref.com/news/viewnews.html?id=691http://www.therpf.com/f11/has-anyone-done-hl-10-lifting-body-54417/index4.html
http://www.therpf.com/f11/has-anyone-done-hl-10-lifting-body-54417/index4.html
http://www.aerospaceweb.org/question/spacecraft/q0153.shtml
« Last Edit: 12/16/2012 08:33 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline john smith 19

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Did not Northrop Grumman buy scaled?
True. while it's not exactly hidden NG don't seem to make a big thing of it and Scaled certainly don't go out of their way to remind people they are actually owned by anyone.
Quote
http://www.businesswire.com/news/home/20121005005907/en/Virgin-Galactic-Acquires-Full-Ownership-Spaceship-Company

Me smells Sir Richard me thinks... ::)
Given Sir Richard's  approach is much more Elon Musk than Jeff Bezos this is very low key by his standards.

Scaled have a reputation for brilliant design and manufacture of 1 off or 2 off aircraft. This was problematical for an ongoing business. This suggests that VG are happy with the design and prepared to commit and freeze it. Odd as I though they still had more of the test programme to complete.

OTOH if that's the case then (in principle) anyone wanting a new WK2 could just buy it from TSC, although that's likely to be quite a bit more expensive than renting time.

Note that in practice I doubt this will make any substantial change to the operations of TSC or VG, with the possible return of seconded staff back to Scaled.

Too bad about SNC being too big for an air drop from a transport aircraft. Not quite as small as I thought. I suggested the heli drop and rocket assisted climb because it seemed the simplest fit to what they've already done. On a limited budget (and there's is very limited) that seems like a good idea. I agree this will fly long before Stratolaunch if the funding is there. There is just so much less basic engineering, design and mfg to do.

The funding is the issue. So the question is how the negotiations on averting the drive off the fiscal cliff in 15 days time are going.  :(
"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 Rocket Science

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Did not Northrop Grumman buy scaled?
True. while it's not exactly hidden NG don't seem to make a big thing of it and Scaled certainly don't go out of their way to remind people they are actually owned by anyone.
Quote
http://www.businesswire.com/news/home/20121005005907/en/Virgin-Galactic-Acquires-Full-Ownership-Spaceship-Company

Me smells Sir Richard me thinks... ::)
Given Sir Richard's  approach is much more Elon Musk than Jeff Bezos this is very low key by his standards.

Scaled have a reputation for brilliant design and manufacture of 1 off or 2 off aircraft. This was problematical for an ongoing business. This suggests that VG are happy with the design and prepared to commit and freeze it. Odd as I though they still had more of the test programme to complete.

OTOH if that's the case then (in principle) anyone wanting a new WK2 could just buy it from TSC, although that's likely to be quite a bit more expensive than renting time.

Note that in practice I doubt this will make any substantial change to the operations of TSC or VG, with the possible return of seconded staff back to Scaled.

Too bad about SNC being too big for an air drop from a transport aircraft. Not quite as small as I thought. I suggested the heli drop and rocket assisted climb because it seemed the simplest fit to what they've already done. On a limited budget (and there's is very limited) that seems like a good idea. I agree this will fly long before Stratolaunch if the funding is there. There is just so much less basic engineering, design and mfg to do.

The funding is the issue. So the question is how the negotiations on averting the drive off the fiscal cliff in 15 days time are going.  :(
Yea, I miss the pretty girls that are usually in his photo ops announcements...  ;D
"The laws of physics are unforgiving"

Offline Todd Martin

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The Enterprise did gliding, approach and landing tests while piggybacking on top of a Boeing 747.  The shuttle FTA separated from the 747 at altitude!  I've seen the original model airplane in Muncie Indiana which proved the concept.  I'm sure Dreamchaser could fit nicely on top of a 747 as well.


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Which would allow for better testing, riding on top of the plane, like Enterprise on the 747, or being suspended under the plane like the HL10 with the B-52 or SSx with the White Knight ?


Offline Rocket Science

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This is the aircraft they could hire for DC air launch, the Ant-225. It has the mounts on top of the fuselage for transport for Buran and the tail configuration for adequate clearance during release...

http://news.kievukraine.info/2008/02/ukraine-china-to-set-up-aerospace.html

http://aircraft-flightsimulator.com/page/4/

http://www.aircharterservice.com/aircraft/cargo/antonov-an-225
« Last Edit: 12/19/2012 02:32 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline RanulfC

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Which would allow for better testing, riding on top of the plane, like Enterprise on the 747, or being suspended under the plane like the HL10 with the B-52 or SSx with the White Knight ?
The "problem" with the SCA, (747) is the need to build new positional and mounting brackets for the DC. There is also an "issue" if the DC can generate enough "lift" to clear the top of the SCA during a "drop" test. (The Shuttle wings provided enough "glide" for a clean seperation as long as the SCA dove away at full power. The DC might not have enough lift to do the same)

This would be an issue for ANY top mounted release though, that includes the AN-225. (IIRC there are a couple of other modified "airframes" in Russia for top carry but the main "problem" still remains)

In many ways the "drop" (B-52/WK2) method would avoid the majority of the issues from top or cargo drop methods, but it then again requires an Aircraft capable of carrying the DC to drop altitude and releasing it. I suspect the Skycrane is going to have to suffice for many of the early tests, but "I" don't see them doing rocket boosted tests from there.

Then again thinking on the subject I recall a "mod" for the Orbiter sim where you have a set of wings and engines that you attach to the baseline "Orbiter" vehicle that allows you to fly the vehicle to its own air-launch position. All cockpit controls and aircraft interfaces run through the cockpit of the DC in this case and it flies around like a "normal" aircraft until the drop point. The "aircraft" portion would then self-recover under remote or on-board guidance and the DC would fly the rest of the profile on its own. This could be useful both for testing and at an advanced level it might provide for suborbital flights.
S
omething like that might be an interesting "aside" to study for the DC at some point...

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Lurker Steve

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Which would allow for better testing, riding on top of the plane, like Enterprise on the 747, or being suspended under the plane like the HL10 with the B-52 or SSx with the White Knight ?
The "problem" with the SCA, (747) is the need to build new positional and mounting brackets for the DC. There is also an "issue" if the DC can generate enough "lift" to clear the top of the SCA during a "drop" test. (The Shuttle wings provided enough "glide" for a clean seperation as long as the SCA dove away at full power. The DC might not have enough lift to do the same)

This would be an issue for ANY top mounted release though, that includes the AN-225. (IIRC there are a couple of other modified "airframes" in Russia for top carry but the main "problem" still remains)

In many ways the "drop" (B-52/WK2) method would avoid the majority of the issues from top or cargo drop methods, but it then again requires an Aircraft capable of carrying the DC to drop altitude and releasing it. I suspect the Skycrane is going to have to suffice for many of the early tests, but "I" don't see them doing rocket boosted tests from there.

Then again thinking on the subject I recall a "mod" for the Orbiter sim where you have a set of wings and engines that you attach to the baseline "Orbiter" vehicle that allows you to fly the vehicle to its own air-launch position. All cockpit controls and aircraft interfaces run through the cockpit of the DC in this case and it flies around like a "normal" aircraft until the drop point. The "aircraft" portion would then self-recover under remote or on-board guidance and the DC would fly the rest of the profile on its own. This could be useful both for testing and at an advanced level it might provide for suborbital flights.
S
omething like that might be an interesting "aside" to study for the DC at some point...

Randy

I assume whatever aircraft is chosen, they would need to make some modifications to add the necessary structure for carrying DC. Since this pretty much takes the aircraft out of service for other purposes, it's almost like SNC would need to purchase the carrier aircraft. I'm sure there are plenty of candidate aircraft sitting in the desert, but probably nothing that can be flight-worthy in less than a year.

Offline Rocket Science

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The AN 225 really isn’t going to need much in the way of internal structural bracing since she could carry an orbiter on her back. As far as mods go she already has the hard points to mount a rack to. As long as the rack is high enough and in clean air, separation should be possible. The handing qualities of the DC should be fairly close to a HL-20 I simmed  years back... There is nothing “evil” in a lifting body that seems to spook a lot of folks who don’t understand its aerodynamics (not aimed at anyone in particular). No big deal for any competent pilot, much better than me, espicially a former NASA Shuttle commander... CFD and a wind tunnel can verify any problems ahead of time.

Another option is to "not fly” the DC off the 225. A long rack (mounted up top) with rollers can allow her to slide off the rack behind the 225 safely using simple aero drag and or a drogue chute at the rear of DC.
 
HMX will know what I’m talking about...  ;)

Like I tell my applied physics students... “Lateral thinking people... lateral thinking”...
« Last Edit: 12/19/2012 07:10 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline RanulfC

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The AN 225 really isn’t going to need much in the way of internal structural bracing since she could carry an orbiter on her back. As far as mods go she already has the hard points to mount a rack to. As long as the rack is high enough and in clean air, separation should be possible.
"Structural" no, but the Orbiter it was designed to carry is far larger than the DC and that means that either they are going to have to fit a 'secondary' system onto the existing system that down-sizes to fit the DC or they are going to have to actually modify the hard-points themselves.
(Obviously the first is going to be "cheaper-and-easier" on the AN-225 but maybe not so much for SN since they would probably have to build and certify it and THEN convince the Russians to take the AN-225 off the market long enough to do fitting and then the drop tests)

The "rack" is the question though because so far the DC has been doing everything from the "top" and such a set up would require re-working to carry and load bear through the bottom. All of this would be on SN's dime.
Quote
The handing qualities of the DC should be fairly close to a HL-20 I simmed  years back... There is nothing “evil” in a lifting body that seems to spook a lot of folks who don’t understand its aerodynamics (not aimed at anyone in particular). No big deal for any competent pilot, much better than me, espicially a former NASA Shuttle commander... CFD and a wind tunnel can verify any problems ahead of time.
And will hopefully :) But it's a consideration that a lifting body does NOT have the same lift as a winged body :)

Lifting bodies are very good at what they are designed to do which is "lift" using more body and speed than wing-area-to-mass to achieve the same lift. There actually IS nothing "evil" about them as I well know. I also happen to know they are not and are probably never going to be AS good as a "winged" lift vehicle at lower speeds :)

I'm not "picking" on DC here either if that helps :) I had a LOT of issues with the PlanetSpace Silver Dart Lifting Body because I happen to KNOW it was going to be a very, very "hot-bird" to land without some sort of lifting enhancment system for low speeds.
Quote
Another option is to "not fly” the DC off the 225. A long rack (mounted up top) with rollers can allow her to slide off the rack behind the 225 safely using simple aero drag and or a drogue chute at the rear of DC.
 
HMX will know what I’m talking about...  ;)

Like I tell my applied physics students... “Lateral thinking people... lateral thinking”...
Well, yes.. But then you're dumping the DC into the wake of the AN-225 which brings up it's own issues :)

I'd "assume" someone has or will sit down with the first couple of drop flights worth of data and some wind-tunnel work to see if the DC generates enough lift to be able to 'fly' off the back of a carrier aircraft. If not then they will probably have to go with "drop" being the operative phrase...

("Lateral" thinking puts me in mind of a very long, very conveluted discussion somewhere on "Air-Launch" of a rocket vehicle that began to get a bit snappish until we discovered that the "other" side of the argument had simply "assumed" we were talking about shoving the LV out the side hatch on an air-freighter instead of using the T-LAD system. The whole other-side argument began to make a LOT more sense after that since frankly "I" couldn't figure out how you'd manage that little trick either :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Rocket Science

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Hey Randy,
Yup, wake turbulence would have to be dealt with in the flight profile, such as the 225 will have to pitch down and bank away, DC will have to pitch up slightly and may need to bank slightly opposite. The vortices descend and DC will want to stay out of them... That’s where the wind tunnel time comes in handy.  :) The SNC folks seem very methodical in their approach and I’m sure they will come up with a solution...

Here is a link for L/D of lifting bodies compared to the X-15 and Shuttle just for reference... Not as good as my first glider a Blanik L-13, but good enough... ;)

http://ia600609.us.archive.org/23/items/nasa_techdoc_19990052613/19990052613.pdf
"The laws of physics are unforgiving"

Offline vt_hokie

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Since we're in the world of speculation, is there any way to hang it under a commercial airliner-sized a/c a la Orbital's L1011?

Offline Rocket Science

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Since we're in the world of speculation, is there any way to hang it under a commercial airliner-sized a/c a la Orbital's L1011?
They would need to extend the gear at minimum and Orbital is a competitor for cargo to ISS...So I guess their aircraft is out...
"The laws of physics are unforgiving"

Offline Elmar Moelzer

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Here is a link for L/D of lifting bodies compared to the X-15 and Shuttle just for reference... Not as good as my first glider a Blanik L-13, but good enough... ;)

http://ia600609.us.archive.org/23/items/nasa_techdoc_19990052613/19990052613.pdf

Very cool! Thanks!

Offline watermod

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What altitude does it need to be dropped from and what speed?

I can't help thinking of using a blimp.

It would be great PR for one of the blimp or modern Zeppelin companies.
 

Offline RanulfC

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What altitude does it need to be dropped from and what speed?

I can't help thinking of using a blimp.

It would be great PR for one of the blimp or modern Zeppelin companies.
The lower the initial airspeed the higher the drop has to be so the vehicle can build up lift.

Not sure what the "stall" speed is put it's likely higher than a blimps "Maximum" speed :)

Since we're in the world of speculation, is there any way to hang it under a commercial airliner-sized a/c a la Orbital's L1011?
As noted I don't think the Orbital L101 is going to be "available" but having said that AirLaunch figured a way to get good size "margin" under a "standard" 747 (@10 feet IIRC) which might allow such a carry given enough mods to allow such. I think the biggie is going to be fin clearance to allow the DC to fit.

Hey Randy,
Yup, wake turbulence would have to be dealt with in the flight profile, such as the 225 will have to pitch down and bank away, DC will have to pitch up slightly and may need to bank slightly opposite. The vortices descend and DC will want to stay out of them... That’s where the wind tunnel time comes in handy.  :) The SNC folks seem very methodical in their approach and I’m sure they will come up with a solution...
Same here :) I'm not saying it can't be done, more a question of what they have the budget to do overall.

I mean if you REALLY want to get "cheap-and-easy" Jordin Kare suggested a down-and-dirty "14th Century Launch Assist" concept at one point that would be perfect :)

Stretch a cable across the Grand Canyon, (one side is higher than the other and the vehicle would be on the "high" side) with one end attached to the vehicle and the other a very large "bucket" of water. "Knock" the bucket off the far side and let physics have it's way :)
Quote
Here is a link for L/D of lifting bodies compared to the X-15 and Shuttle just for reference... Not as good as my first glider a Blanik L-13, but good enough... ;)

http://ia600609.us.archive.org/23/items/nasa_techdoc_19990052613/19990052613.pdf
Thanks! I was actually looking for that one recently for something else I was referencing and couldn't figure out where/if I downloaded it :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline john smith 19

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I mean if you REALLY want to get "cheap-and-easy" Jordin Kare suggested a down-and-dirty "14th Century Launch Assist" concept at one point that would be perfect :)

Stretch a cable across the Grand Canyon, (one side is higher than the other and the vehicle would be on the "high" side) with one end attached to the vehicle and the other a very large "bucket" of water. "Knock" the bucket off the far side and let physics have it's way :)
Thanks! I was actually looking for that one recently for something else I was referencing and couldn't figure out where/if I downloaded it :)

A few years ago a documentary recreated the plan to escape from the Colditz PoW camp in WWII by building a glider using bedsheets. The launch assist was a bathtub filled with concrete.

The flight was viewed as too high risk so they used radio control and weights to simulate the 2 person crew. It take off and reached the landing area safely.

However you're still pretty close to ground level.
"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 RanulfC

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I mean if you REALLY want to get "cheap-and-easy" Jordin Kare suggested a down-and-dirty "14th Century Launch Assist" concept at one point that would be perfect :)

Stretch a cable across the Grand Canyon, (one side is higher than the other and the vehicle would be on the "high" side) with one end attached to the vehicle and the other a very large "bucket" of water. "Knock" the bucket off the far side and let physics have it's way :)
Thanks! I was actually looking for that one recently for something else I was referencing and couldn't figure out where/if I downloaded it :)

A few years ago a documentary recreated the plan to escape from the Colditz PoW camp in WWII by building a glider using bedsheets. The launch assist was a bathtub filled with concrete.

The flight was viewed as too high risk so they used radio control and weights to simulate the 2 person crew. It take off and reached the landing area safely.

However you're still pretty close to ground level.
Yep it is ONLY an "assist" and you'd still need to do a pull up manuever and light the rockets but it DOES gain you something :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Robotbeat

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What the heck does this have to do with anything?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline john smith 19

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What the heck does this have to do with anything?
Well with WK2 unavailable for widening the flight envelope how else can you get the altitude and speed you need to test its landing range?
"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 vt_hokie

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What the heck does this have to do with anything?
Well with WK2 unavailable for widening the flight envelope how else can you get the altitude and speed you need to test its landing range?

The "Super Valkyrie"?

Offline john smith 19

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The "Super Valkyrie"?
I think they need an aircraft that flew some time this century.
"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 Lurker Steve

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The "Super Valkyrie"?
I think they need an aircraft that flew some time this century.

The "Super Valkyrie", if it really exists, should be a newer airframe than most, if not all B-52s. Unfortunately, I don't think the Airforce likes the general public taking pictures of the aircraft that fly around Groom Lake, so they probably wouldn't make it available for use by a vehicle like Dream Chaser, that would be photographed during the flight tests.

Offline mr. mark

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I have to ask this question so, sorry. What happens if Dreamchaser cannot get a ride?

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I have to ask this question so, sorry. What happens if Dreamchaser cannot get a ride?
Damned good question.
Maybe they could do sub orbital hops on a launch vehicle. That sure would increase the cost though.
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Offline Jim

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The "Super Valkyrie"?
I think they need an aircraft that flew some time this century.

How about just flew?

Offline Zed_Noir

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I have to ask this question so, sorry. What happens if Dreamchaser cannot get a ride?

Wonder if the Star Grazer L-1011 is available from Orbital, since the Pegasus don't have many missions lined up.

Offline Lars_J

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I have to ask this question so, sorry. What happens if Dreamchaser cannot get a ride?

Wonder if the Star Grazer L-1011 is available from Orbital, since the Pegasus don't have many missions lined up.

How in the world would an L-1011 be able to lift a DC? There just isn't room enough under the fuselage.

(see http://www.flickr.com/photos/orbitalsciences/7338418194/ )

Offline Rocket Science

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Since we are still discussing this allow me to give you another option. Jet airliners often ferry extra engines on a pylon beneath their wings. Theoretically they could adapt one under a Boeing 747 or a DC10 for example with sufficient clearance for DC... Like I keep saying there are many alternatives all that is required is “lateral thinking”...

http://www.airliners.net/aviation-forums/tech_ops/read.main/200315/
http://www.airliners.net/aviation-forums/tech_ops/read.main/238736/
« Last Edit: 12/28/2012 12:02 AM by Rocket Science »
"The laws of physics are unforgiving"

Offline john smith 19

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Since we are still discussing this allow me to give you another option. Jet airliners often ferry extra engines on a pylon beneath their wings. Theoretically they could adapt one under a Boeing 747 or a DC10 for example with sufficient clearance for DC... Like I keep saying there are many alternatives all that is required is “lateral thinking”...
Now this I did not know. I'd always figured they'd put the engine on a standard engine pod location and fly with 3 live engines (thinking further I can see this being difficult with modern 2 engine designs). Is this a design certification (IE all aircraft of a type can do it) or does it need special clearance from the relevant authorities?

The ground clearance should be adequate but the inter-pod separation?

It's something I've never seen before but I'm guessing the joker is in the paperwork. I strongly doubt you can hire an aircraft from an airline, hang DC on the pylon, run the tests and hand the aircraft back to them.

But definitely something I'll be filling in the "More common than you think" drawer.  :)
[edit]Read one of the links posted. The DC-8 hit M1.01 in a dive from 52kft to 41kft in 1961. I did not believe any big commercial jet had deliberately done this.
http://www.airliners.net/aviation-forums/tech_ops/read.main/200315/
Reply from Viscount724.

And in the press release for it (a bit suspicious) the implication is even that it is "routine" and they were going to ship it to a customer.  :o
http://www.dc8.org/library/supersonic/index.php

This link shows a fairly detailed description of the DC-8 flight which might be relevant should you could consider repeating it.

http://www.dc-8jet.com/0-dc8-sst-flight.htm

Skip the drop test and drop the whole aircraft?  :)
[edit]
« Last Edit: 12/28/2012 07:49 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 adrianwyard

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Intuitively, releasing DC at high speed from below a carrier aircraft - something like WK2 - sounds like the best option because this is closest to how it will begin its subsonic flight when operational. But in reality what are the downsides to high-altitude drop from helicopter?

Here's an optimistic guess on how it could work: Attach a large-ish chute to the rear hatch area (larger than the one used in the captive carry flight) to orient the craft into the airstream, and then keep it nose down after release from the copter until airspeed picks up, at which point you jettison it.

I bet a big chute could keep the helicopter's forward airspeed quite low, but wouldn't some airflow (control authority) coupled with the chute be sufficient to keep it stable as speed picks up and the aerosurfaces gain effectiveness. And it'll drop like a rock, so you'd be faster than stall-speed very quickly, and so be able to begin to pull out of the stall/dive, but my guess is the nose would be pointed straight at the ground by the time you let the chute go, and those control surfaces are not that big, so it's important to remember to start the test from a very great height!
« Last Edit: 12/28/2012 01:01 PM by adrianwyard »

Offline Rocket Science

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Since we are still discussing this allow me to give you another option. Jet airliners often ferry extra engines on a pylon beneath their wings. Theoretically they could adapt one under a Boeing 747 or a DC10 for example with sufficient clearance for DC... Like I keep saying there are many alternatives all that is required is “lateral thinking”...
Now this I did not know. I'd always figured they'd put the engine on a standard engine pod location and fly with 3 live engines (thinking further I can see this being difficult with modern 2 engine designs). Is this a design certification (IE all aircraft of a type can do it) or does it need special clearance from the relevant authorities?

The ground clearance should be adequate but the inter-pod separation?

It's something I've never seen before but I'm guessing the joker is in the paperwork. I strongly doubt you can hire an aircraft from an airline, hang DC on the pylon, run the tests and hand the aircraft back to them.

But definitely something I'll be filling in the "More common than you think" drawer.  :)
[edit]Read one of the links posted. The DC-8 hit M1.01 in a dive from 52kft to 41kft in 1961. I did not believe any big commercial jet had deliberately done this.
http://www.airliners.net/aviation-forums/tech_ops/read.main/200315/
Reply from Viscount724.

And in the press release for it (a bit suspicious) the implication is even that it is "routine" and they were going to ship it to a customer.  :o
http://www.dc8.org/library/supersonic/index.php

This link shows a fairly detailed description of the DC-8 flight which might be relevant should you could consider repeating it.

http://www.dc-8jet.com/0-dc8-sst-flight.htm

Skip the drop test and drop the whole aircraft?  :)
[edit]

I don’t want to take this OT but if you are interested in engine out discussion there is more to read here:

http://www.airliners.net/aviation-forums/tech_ops/read.main/308222/

When it comes to using an airliner for a DC drop test there is no need to take one out of service. There are loads of these sitting out in the desert for long term storage that can be leased or purchased if the wish to and modified. Since these flights are going to be over an experimental flight test range with no paying passengers, the normal airliner regs don’t need to be complied with. Conceivably you could remove one engine from a 747, lightly load it with fuel and use the pylon to carry and drop DC from it with modifications... No need for high Mach numbers to drop DC...
« Last Edit: 12/28/2012 01:23 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline Lurker Steve

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Since we are still discussing this allow me to give you another option. Jet airliners often ferry extra engines on a pylon beneath their wings. Theoretically they could adapt one under a Boeing 747 or a DC10 for example with sufficient clearance for DC... Like I keep saying there are many alternatives all that is required is “lateral thinking”...
Now this I did not know. I'd always figured they'd put the engine on a standard engine pod location and fly with 3 live engines (thinking further I can see this being difficult with modern 2 engine designs). Is this a design certification (IE all aircraft of a type can do it) or does it need special clearance from the relevant authorities?

The ground clearance should be adequate but the inter-pod separation?

It's something I've never seen before but I'm guessing the joker is in the paperwork. I strongly doubt you can hire an aircraft from an airline, hang DC on the pylon, run the tests and hand the aircraft back to them.

But definitely something I'll be filling in the "More common than you think" drawer.  :)
[edit]Read one of the links posted. The DC-8 hit M1.01 in a dive from 52kft to 41kft in 1961. I did not believe any big commercial jet had deliberately done this.
http://www.airliners.net/aviation-forums/tech_ops/read.main/200315/
Reply from Viscount724.

And in the press release for it (a bit suspicious) the implication is even that it is "routine" and they were going to ship it to a customer.  :o
http://www.dc8.org/library/supersonic/index.php

This link shows a fairly detailed description of the DC-8 flight which might be relevant should you could consider repeating it.

http://www.dc-8jet.com/0-dc8-sst-flight.htm

Skip the drop test and drop the whole aircraft?  :)
[edit]

I don’t want to take this OT but if you are interested in engine out discussion there is more to read here:

http://www.airliners.net/aviation-forums/tech_ops/read.main/308222/

When it comes to using an airliner for a DC drop test there is no need to take one out of service. There are loads of these sitting out in the desert for long term storage that can be leased or purchased if the wish to and modified. Since these flights are going to be over an experimental flight test range with no paying passengers, the normal airliner regs don’t need to be complied with. Conceivably you could remove one engine from a 747, lightly load it with fuel and use the pylon to carry and drop DC from it with modifications... No need for high Mach numbers to drop DC...


What is the size of the DC compared to the standard Rolls Royce or GE Jet Engine ? Is there enough clearance if the DC is connected to a standard engine pylon ? I was thinking that the DC needed something with the wings mounted up high, like the B-52 so there was enough ground clearance. If any 4-engine jumbo jet will do, that makes it easier. I assume a standard 747 or equivalent AirBus craft has the lift capability to handle a 10-15 ton craft attached to the wing.

Offline ChefPat

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Where is Stratolaunch on the modifications to their carrier aircraft? It would certainly be large enough to handle a Dreamchaser.
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Offline mr. mark

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Based on what I'm hearing, it looks like there will be no drop test until late 2013- 2014. It takes time to adapt out a system and look at all possibilities. 

Offline adrianwyard

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Based on what I'm hearing, it looks like there will be no drop test until late 2013- 2014. It takes time to adapt out a system and look at all possibilities. 

Attaching a jettisonable parachute to DC's tail, and dropping from high altitude by helicopter doesn't sound like the sort of thing that would take till late 2013, or does it?

Offline Lurker Steve

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Based on what I'm hearing, it looks like there will be no drop test until late 2013- 2014. It takes time to adapt out a system and look at all possibilities. 

Attaching a jettisonable parachute to DC's tail, and dropping from high altitude by helicopter doesn't sound like the sort of thing that would take till late 2013, or does it?

There are definately some low altitude / low speed tests they can do with the helicopter, including the first free-flight and landing tests.

Offline adrianwyard

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I think so. But if that's the case, what test(s) will a helicopter be insufficient for?

Based on what I'm hearing, it looks like there will be no drop test until late 2013- 2014. It takes time to adapt out a system and look at all possibilities. 

Attaching a jettisonable parachute to DC's tail, and dropping from high altitude by helicopter doesn't sound like the sort of thing that would take till late 2013, or does it?

There are definately some low altitude / low speed tests they can do with the helicopter, including the first free-flight and landing tests.


Offline john smith 19

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Where is Stratolaunch on the modifications to their carrier aircraft? It would certainly be large enough to handle a Dreamchaser.
A long way from even being constructed.
"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 Rocket Science

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Keep in mind folks that we are talking about two different series of flight tests. Low altitude unmanned flight tests with “autoland” and high altitude manned flight tests in the schedule.

Here are the performance specs for the Skycrane.

http://www.sikorskyarchives.com/S-64_Product_History%20modX.php

« Last Edit: 12/28/2012 05:35 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline ChefPat

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Where is Stratolaunch on the modifications to their carrier aircraft? It would certainly be large enough to handle a Dreamchaser.
A long way from even being constructed.
Are they? They've had the 2 jets for more than ten months now. How long does it take to modify them?
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Offline Rocket Science

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Where is Stratolaunch on the modifications to their carrier aircraft? It would certainly be large enough to handle a Dreamchaser.
A long way from even being constructed.
Are they? They've had the 2 jets for more than ten months now. How long does it take to modify them?
It’s a whole new aircraft Pat. Only the engines and subsystems are from the donor aircraft.
"The laws of physics are unforgiving"

Offline RanulfC

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Based on what I'm hearing, it looks like there will be no drop test until late 2013- 2014. It takes time to adapt out a system and look at all possibilities. 
Sounds about right, maybe a little later depending...

I get the feeling some folks are not really "thinking" this all the way through :)

Attaching a jettisonable parachute to DC's tail, and dropping from high altitude by helicopter doesn't sound like the sort of thing that would take till late 2013, or does it?

I didn't actually "comment" on the original suggestion of this and I probably should have :)

You're not going to "need" to attach a "jettisonable" parachute to the DC-ETV, there is already one in place: the "drag" stabilization parachute :) They'd just have to move it from the current mounting (above the tether attach point) to a vehicle mounting point.

You're also not going to get QUITE that radical during the drop, (no "nose-at-the-ground" attitude) but you WILL eat up a lot of altitude generating enough "lift" overall to hit the "landing speed" targeted (191-knots/354kph/220mph) let alone higher. (Landing speed is noted here:
http://www.nasaspaceflight.com/2012/06/snc-dream-chasers-enterprise-test-approach/ )



The "issue" here is "dropping from high altitude" with a helicopter. Especially with the DC lifting body.

We've got several "facts" to work with already:
The stats for the Skycrane can be found here:
http://www.ericksonaircrane.com/

Note: Maxium "hook" weight is the important figure here. The S-64E can lift up to 9,072kg (20,000lbs) while the S-64F can lift up to 11,340kg (25,000lbs) with a "maxium" cruise speed of 115-knots (212kph/132mph) for the former and 104-knots (192kph/119mph) with the latter.

This is important for several reasons but the "biggie" is that these figures (for the Skycrane(s)) is for rather LOW altitude, well below 20,000ft. (As a comparison you can see the Shuttle A-and-L tests here, ya "wikipedia" I know but the general data is accurate, http://en.wikipedia.org/wiki/Approach_and_Landing_Tests :) )
The "highest" altitude recorded for the "type" for the S-64 is held by an earlier version for the US Army the "CH-54" which reached a maxium altitude of 36,000ft but this was with NO load, limited fuel/crew, no forward speed, etc so that it COULD reach that high. "Typical" maximum operational altitude is listed as a bit over 18,000ft but again that's NOT going to be with a full load, nor at "high" speed.

Helicopters like all "active" lift vehicles have a limit of what they can lift that goes DOWN with altitude, as does speed. (You have to trade "lift" power for speed power) So in general we're looking at a "probable" release at or around 10,000ft at most.

"Assuming" the DC-ETV mass' somewhat close to the "operational" launch mass of around 11,340kg the Helo flying it must be the F model which means a lower intial speed to start off with. If it's below 9,000kg they could use the E model but then the "flying" characteristics will be a lot different than the "actual" DC orbiter vehicle.

It could very easily be MORE than a year or two to get all the data needed to even see if they actually CAN use a helo to do "free-flight" drop tests for the DC-ETV. In general the DC-ETV has to "fall" fast enough, from high enough to generate a viable speed of almost 200-knots, (370kph/230mph) from a possible "maximum" drop speed of between 104 to 115-knots,(192kph/119mph to 212kph/132mph) and that's non-trivial.

As an example I'd point to the fact that NASA did this testing type mission when evaluating the low-speed handling characteristics of the "staight-wing" versus the "delta-wing" versions of the Shuttle. Most of them still ended up "pranging" the nose of the model pretty good because they simply couldn't generate enough lift from a zero-speed drop IIRC.
And that's a WINGED vehicle and not a lifting body :)


There are definately some low altitude / low speed tests they can do with the helicopter, including the first free-flight and landing tests.
Well "sort-of" at any rate...

The big factor is how far does it have to "fall" to get the needed speed to fly. With a landing speed of around 370kph/230mph and the vehicle length and width (span) which is listed as 8.84m (L) by 7.16m (W) and the mass of the vehicle which we probably should "assume" is near-flight weight of 11,430kg...

I think so. But if that's the case, what test(s) will a helicopter be insufficient for?
My take would be pretty much everything BUT a very limited "landing" speed test series and THAT only if all the numbers add up so that it can reach "minimum" speed within the altitude envelope available.

They really need a "carrier" aircraft for flight testing both to give it the intial minimum speed and a better altitude to work from. Which brings me to the idea of "hanging" the DC-ETV from a "normal" airliner mounting station. My take is its do-able as long as the station can be configured (a mounting pylon/bracket) and is able to handle the load. Which points to a particular issue; mass. Most of the engine weights I'm seeing do not exceed 4,000kg to 5000kg which is far below even the "low" estimated mass of the DC-ETV of 9,000kg. And that doesn't take into effect the mass of the "pylon" and mounting system. It's possible they could make a mount that would "span" say an inboard engine mount and the ferry engine mount but even then the total "weight" capacity of the mounts probably won't be enough to carry the load.

Now if the overall mass of the DC-ETV IS lower than anything listed they could very well use such an arrangment to test fly the vehicle HOWEVER the "tests" will be very far off the mark for any comparision to the "real-thing" because of the lift/drag/mass-ratio of the test vehicle.
(A low mass test vehicle will glide and generally fly much better than something that is close to the actual planned vehicle mass which would throw off any results)

Guess we'll have to wait and see.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Rocket Science

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10,000 will give us about 30 seconds flying time till touchdown... Wooo! 8)
"The laws of physics are unforgiving"

Offline john smith 19

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The "issue" here is "dropping from high altitude" with a helicopter. Especially with the DC lifting body.

We've got several "facts" to work with already:
The stats for the Skycrane can be found here:
http://www.ericksonaircrane.com/

Note: Maxium "hook" weight is the important figure here. The S-64E can lift up to 9,072kg (20,000lbs) while the S-64F can lift up to 11,340kg (25,000lbs) with a "maxium" cruise speed of 115-knots (212kph/132mph) for the former and 104-knots (192kph/119mph) with the latter.

This is important for several reasons but the "biggie" is that these figures (for the Skycrane(s)) is for rather LOW altitude, well below 20,000ft. (As a comparison you can see the Shuttle A-and-L tests here, ya "wikipedia" I know but the general data is accurate, http://en.wikipedia.org/wiki/Approach_and_Landing_Tests :) )
The "highest" altitude recorded for the "type" for the S-64 is held by an earlier version for the US Army the "CH-54" which reached a maxium altitude of 36,000ft but this was with NO load, limited fuel/crew, no forward speed, etc so that it COULD reach that high. "Typical" maximum operational altitude is listed as a bit over 18,000ft but again that's NOT going to be with a full load, nor at "high" speed.

Helicopters like all "active" lift vehicles have a limit of what they can lift that goes DOWN with altitude, as does speed. (You have to trade "lift" power for speed power) So in general we're looking at a "probable" release at or around 10,000ft at most.

"Assuming" the DC-ETV mass' somewhat close to the "operational" launch mass of around 11,340kg the Helo flying it must be the F model which means a lower intial speed to start off with. If it's below 9,000kg they could use the E model but then the "flying" characteristics will be a lot different than the "actual" DC orbiter vehicle.
That looks like the big problem with drops from helicopters (even big ones). It looks like the only way to make this work is to use the hybrid rocket
Quote
It could very easily be MORE than a year or two to get all the data needed to even see if they actually CAN use a helo to do "free-flight" drop tests for the DC-ETV. In general the DC-ETV has to "fall" fast enough, from high enough to generate a viable speed of almost 200-knots, (370kph/230mph) from a possible "maximum" drop speed of between 104 to 115-knots,(192kph/119mph to 212kph/132mph) and that's non-trivial.

As an example I'd point to the fact that NASA did this testing type mission when evaluating the low-speed handling characteristics of the "staight-wing" versus the "delta-wing" versions of the Shuttle. Most of them still ended up "pranging" the nose of the model pretty good because they simply couldn't generate enough lift from a zero-speed drop IIRC.
And that's a WINGED vehicle and not a lifting body :)

My take would be pretty much everything BUT a very limited "landing" speed test series and THAT only if all the numbers add up so that it can reach "minimum" speed within the altitude envelope available.
[/quote]
So better than nothing but unlikely to deliver the full envelope needed?

Quote
They really need a "carrier" aircraft for flight testing both to give it the intial minimum speed and a better altitude to work from. Which brings me to the idea of "hanging" the DC-ETV from a "normal" airliner mounting station. My take is its do-able as long as the station can be configured (a mounting pylon/bracket) and is able to handle the load. Which points to a particular issue; mass. Most of the engine weights I'm seeing do not exceed 4,000kg to 5000kg which is far below even the "low" estimated mass of the DC-ETV of 9,000kg. And that doesn't take into effect the mass of the "pylon" and mounting system. It's possible they could make a mount that would "span" say an inboard engine mount and the ferry engine mount but even then the total "weight" capacity of the mounts probably won't be enough to carry the load.
And that's before you take into account the mounting hardware. An 11 000Kg vehicle would suggest an engine in the 55 000 to 110 000 Kg thrust range. Does anyone have such an engine? Wikipedia says the GE90 is the biggest in the world at 16644lb, but that's nowhere near big enough.
Quote
Now if the overall mass of the DC-ETV IS lower than anything listed they could very well use such an arrangment to test fly the vehicle HOWEVER the "tests" will be very far off the mark for any comparision to the "real-thing" because of the lift/drag/mass-ratio of the test vehicle.
(A low mass test vehicle will glide and generally fly much better than something that is close to the actual planned vehicle mass which would throw off any results)
It does not seem there is an engine big enough (that can be wing carried) that this can replace.
<sigh> It's such a nice idea, and it opens up the range of aircraft that could be used if you have a small enough vehicle to accommodate and it can operate entirely autonomously (no special wiring, no special plumbing).
Too bad. Firing the hybrid looks like the simplest option to get decent altitude and speed.
"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 GClark

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On the subject of dropping lifting bodies from helicopters...

It's not like we have no experience doing this.  Anyone remember Project Parawing?  Hyper-X?  X-40A?  All dropped from helicopters at rather modest altitudes - all landed without incident (In the case of the X-40A multiple times).  We (the metaphysical we) know how to do this.

IMNSHO, much ado about nothing.

Offline Rocket Science

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On the subject of dropping lifting bodies from helicopters...

It's not like we have no experience doing this.  Anyone remember Project Parawing?  Hyper-X?  X-40A?  All dropped from helicopters at rather modest altitudes - all landed without incident (In the case of the X-40A multiple times).  We (the metaphysical we) know how to do this.

IMNSHO, much ado about nothing.

It’s not that it’s a problem... It only useful for a small part of the flight test envelope... For a manned high key approaching the HAC you would really need to be in stable flight at a higher altitude and velocity.
"The laws of physics are unforgiving"

Offline adrianwyard

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In a DC thread some time ago people expressed doubt that one nozzle design could be chosen that would work in vacuum and the atmosphere. I'm not sure if this is in fact that big a problem (shuttle SRM nozzle operated from 0-146K ft without trouble) but if it is, then the hybrids couldn't be used for drop tests

Offline Rocket Science

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In a DC thread some time ago people expressed doubt that one nozzle design could be chosen that would work in vacuum and the atmosphere. I'm not sure if this is in fact that big a problem (shuttle SRM nozzle operated from 0-146K ft without trouble) but if it is, then the hybrids couldn't be used for drop tests

I don’t buy that... SS1 Flew just fine and SS2 will use a similar motor to DC...
"The laws of physics are unforgiving"

Offline adrianwyard

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I don't buy it either. While SS1 started the burn at 50K ft, if the ground tests used the flight nozzle then it clearly runs fine at all altitudes. Perhaps hybrid motor nozzles are less sensitive to expansion ratio issues than others, or the performance losses are simply accepted.

If the RCS can also operate at all altitudes, then technically DC doesn't  need any carrier aircraft at all for low altitude tests: back it up to the end of a long runway, fire the hybrids, then at ~200mph fire the down RCS jets to pick the nose up, fly for a few seconds, cut the hybrids and land. Note: this is not a a serious suggestion, but it certainly would be fun to see tried!

« Last Edit: 12/30/2012 06:33 AM by adrianwyard »

Online kkattula

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...
If the RCS can also operate at all altitudes, then technically DC doesn't  need any carrier aircraft at all for low altitude test: back it up to the end of a long runway, fire the hybrids, then at ~200mph fire the down RCS jets to pick the nose up, fly for a few seconds, cut the hybrids and land. Note: this is not a a serious suggestion, but it certainly would be fun to see tried!


I don't know if the undercarriage can take a fully loaded DC. I really doubt the nose skid is practical for a take-off roll. :)

And RCS is not needed.  DC has aero controls.

But why horizontal take-off at all?  DC's abort mode is VTHL. And IIRC the motors provide up to 1300 m/s delta v. Why not just launch vertically to a reasonably high altitude and pitch over to gain some horizontal velocity before burn out?

« Last Edit: 12/30/2012 06:38 AM by kkattula »

Offline adrianwyard

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Well yes, if we're just joking around (I started it) then it's only slightly more crazy to start with a vertical launch abort-style test.

Heading back to reality:

It sounds like the best guess is a helicopter will be used for low speed low altitude tests. For higher speed tests, we may have wait quite a while until SNC is ready to install/fire the hybrids or design/qualify mounts for an as yet unknown carrier aircraft.

I wonder which of these two is more likely to happen first.
« Last Edit: 12/30/2012 06:57 AM by adrianwyard »

Offline thomasafb

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I seem to remember that in the late 1990s, the DLR made a drop test with a scale model of the Orbiter from an high altitude balloon (in Sweden?). Must have been a test to validate such a capability for Hermes or some other still-born European project. IIRC, the orbiter was remote controlled (and hit a building).

Not sure what came out of the test, but without the availability of a carrier aircraft, dropping DC from a balllon (at least for unmanned drop tests) might be an option.
Visited Shuttles (so far):
OV-104, OV-105

Offline john smith 19

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It sounds like the best guess is a helicopter will be used for low speed low altitude tests. For higher speed tests, we may have wait quite a while until SNC is ready to install/fire the hybrids or design/qualify mounts for an as yet unknown carrier aircraft.

Well the hybrids are a fairly well characterized system and SNC have a relationship with the suppliers.

The high altitude balloon drop is starting to look almost sensible.  :)
"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 adrianwyard

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It sounds like the best guess is a helicopter will be used for low speed low altitude tests. For higher speed tests, we may have wait quite a while until SNC is ready to install/fire the hybrids or design/qualify mounts for an as yet unknown carrier aircraft.

Well the hybrids are a fairly well characterized system and SNC have a relationship with the suppliers.

The high altitude balloon drop is starting to look almost sensible.  :)

Aren't SNC themselves the developers of the hybrids? It sounds cavalier to suggest hybrids be fired early on in the test program (see SS2's large number of unpowered flights) but if the DC motor is as ready for flight testing as the airframe and avionics, then I guess it wouldn't be insane.

Offline Rocket Science

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It sounds like the best guess is a helicopter will be used for low speed low altitude tests. For higher speed tests, we may have wait quite a while until SNC is ready to install/fire the hybrids or design/qualify mounts for an as yet unknown carrier aircraft.

Well the hybrids are a fairly well characterized system and SNC have a relationship with the suppliers.

The high altitude balloon drop is starting to look almost sensible.  :)

Aren't SNC themselves the developers of the hybrids? It sounds cavalier to suggest hybrids be fired early on in the test program (see SS2's large number of unpowered flights) but if the DC motor is as ready for flight testing as the airframe and avionics, then I guess it wouldn't be insane.
There is that old expression “that necessity is the mother of invention”. Since SNC has had the rug pulled out from under them by SCALED/VG they have to alter their test program. Sometimes “a giant leap” is required is required to overcome what might seem like a setback which propels you ahead (pun intended) recall Apollo 8 around the Moon. This is what is great about the private sector is that they can be agile in their approach rather than just generating a lot of studies and PowerPoints... I look at this as an opportunity to shine...
« Last Edit: 12/30/2012 12:50 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline Jim

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I'm not sure if this is in fact that big a problem (shuttle SRM nozzle operated from 0-146K ft without trouble) 

146k does not qualify as vacuum. 

Offline Jim

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I don’t buy that... SS1 Flew just fine and SS2 will use a similar motor to DC...

Not relevant or applicable.

Offline Jim

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If the RCS can also operate at all altitudes,


No such thing.

Offline Rocket Science

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I don’t buy that... SS1 Flew just fine and SS2 will use a similar motor to DC...

Not relevant or applicable.
Jim, a question... Cannot SNC fit whatever sized nozzle to which ever part of the flight envelope they wish to test? It is a bolt-on operation...
"The laws of physics are unforgiving"

Offline Jim

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Jim, a question... Cannot SNC fit whatever sized nozzle to which ever part of the flight envelope they wish to test? It is a bolt-on operation...

Most nozzles for composite SRM's aren't bolt-on

Offline Rocket Science

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Jim, a question... Cannot SNC fit whatever sized nozzle to which ever part of the flight envelope they wish to test? It is a bolt-on operation...

Most nozzles for composite SRM's aren't bolt-on
Yea Jim you are right . ;) I was thinking about the bolts around the circumference on the end case on the ground test motors.  The motors are one piece composite. In that case they would have to produce motors with different optimized nozzles....

Edit to add:

Thinking about this a bit more... DC would have to be able to perform a Pad Abort using standard ops motors and nozzles. So why can’t a single nozzle design be used for the test flights as well?
« Last Edit: 12/30/2012 02:49 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline adrianwyard

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And isn't CST-100 using RS-88 for both abort (from sea level presumably) and orbital maneuvering, i.e. vacuum?

Offline joek

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And isn't CST-100 using RS-88 for both abort (from sea level presumably) and orbital maneuvering, i.e. vacuum?

Only tenuously related to RS-88 AFAICT.  CST-100 abort motors are Bantam-derived but are pressure-fed hypergolic ablative.  No idea if they're intended for orbital maneuvering, although Boeing has made noises about them being potentially used for ISS reboost.

Offline Patchouli

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Jim, a question... Cannot SNC fit whatever sized nozzle to which ever part of the flight envelope they wish to test? It is a bolt-on operation...

Most nozzles for composite SRM's aren't bolt-on
Yea Jim you are right . ;) I was thinking about the bolts around the circumference on the end case on the ground test motors.  The motors are one piece composite. In that case they would have to produce motors with different optimized nozzles....

Edit to add:

Thinking about this a bit more... DC would have to be able to perform a Pad Abort using standard ops motors and nozzles. So why can’t a single nozzle design be used for the test flights as well?

The most obvious solution would be to run a nozzle that is a compromise between what's needed for vacuum and sea level like what was done on the SSME.

You loose some ISP but it likely would be lighter and simpler then using an articulated nozzle extension or aerospike.

The Atlas V is doing most of the work getting to orbit and it's an orbital vehicle so you can afford to have a less then optimal ISP.
« Last Edit: 12/31/2012 02:50 AM by Patchouli »

Offline Lee Jay

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In a DC thread some time ago people expressed doubt that one nozzle design could be chosen that would work in vacuum and the atmosphere. I'm not sure if this is in fact that big a problem (shuttle SRM nozzle operated from 0-146K ft without trouble) but if it is, then the hybrids couldn't be used for drop tests

I asked them specifically if the hybrids would be used for the drop tests, and Mark Sirangelo said that they would be.  I think it's reasonable to assume that he knows what he's talking about given that he's former CEO of Spacedev and current head of SNC Space Systems.

This was in the context of high altitude releases from carrier aircraft, not from the helicopter.

Offline Patchouli

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I wonder if the best option would be to pull the NASA B-52s out of retirement.

Offline Rocket Science

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In a DC thread some time ago people expressed doubt that one nozzle design could be chosen that would work in vacuum and the atmosphere. I'm not sure if this is in fact that big a problem (shuttle SRM nozzle operated from 0-146K ft without trouble) but if it is, then the hybrids couldn't be used for drop tests

I asked them specifically if the hybrids would be used for the drop tests, and Mark Sirangelo said that they would be.  I think it's reasonable to assume that he knows what he's talking about given that he's former CEO of Spacedev and current head of SNC Space Systems.

This was in the context of high altitude releases from carrier aircraft, not from the helicopter.
Exactly Lee Jay, I remember that and that is one of the reasons that I fail to understand the concern over it. The only difference that it would be done later in the test flights as Mark stated. Circumstances have changed and perhaps other options made need to be examined including boost to climb sooner rather than later...
« Last Edit: 12/31/2012 12:21 PM by Rocket Science »
"The laws of physics are unforgiving"

Offline Lee Jay

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In a DC thread some time ago people expressed doubt that one nozzle design could be chosen that would work in vacuum and the atmosphere. I'm not sure if this is in fact that big a problem (shuttle SRM nozzle operated from 0-146K ft without trouble) but if it is, then the hybrids couldn't be used for drop tests

I asked them specifically if the hybrids would be used for the drop tests, and Mark Sirangelo said that they would be.  I think it's reasonable to assume that he knows what he's talking about given that he's former CEO of Spacedev and current head of SNC Space Systems.

This was in the context of high altitude releases from carrier aircraft, not from the helicopter.
Exactly Lee Jay, I remember that and that is one of the reasons that I fail to understand the concern over it. The only difference that it would be done later in the test flights as Mark stated. Circumstances have changed and perhaps other options made need to be examined including boost to climb sooner rather than later...

You know, as usual, Chris is on top of it.  It says this in his article:

http://www.nasaspaceflight.com/2012/06/snc-dream-chasers-enterprise-test-approach/

"“We want to expand the envelope up, starting low, and gradually  increasing in altitude, speed and maneuvers,” added Mr Sirangelo. “It’s  going to have some forward momentum (with the helicopter) as we’re  moving it and then it’s going to drop very quickly, then it’ll pick up  speed and then it’ll pick up lift and then it’ll fly in and do its  work.” The test plan also progresses towards the use of Dream Chaser’s  hybrid motors, for the purpose of expanding the flight envelope to  be both faster and higher, during the later stages of testing."
I'm not sure why there's a question about this.

Offline adrianwyard

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If the RCS can also operate at all altitudes,


No such thing.

Do you say this because it's not possible to design one nozzle that's optimized for all ambient pressures? Or for some other reason?

Offline Jim

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If the RCS can also operate at all altitudes,


No such thing.

Do you say this because it's not possible to design one nozzle that's optimized for all ambient pressures? Or for some other reason?

Thrusters don't have enough power to over come aero forces.  If they do, they are grossly over sized.

Offline adrianwyard

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Aha. Thanks, makes sense.

Offline adrianwyard

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I see the Shuttle orbiter's vernier jets were a scant 25 pounds-force, and main RCS jets were 860 pounds-force. Since DC is ~1/10th the mass of the orbiter, can we guess its' RCS will be closer in size to the Shuttle's verniers?

Offline Lars_J

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I see the Shuttle orbiter's vernier jets were a scant 25 pounds-force, and main RCS jets were 860 pounds-force. Since DC is ~1/10th the mass of the orbiter, can we guess its' RCS will be closer in size to the Shuttle's verniers?

For comparison, Dragon uses 90 lbf thrusters for a much smaller spacecraft, but that is probably an upper bound for what one can expect. (Dracos are a bit oversized due to having to work as deorbit engines as well)

Offline Rocket Science

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All those thrusters are pretty much like throwing “wet Kleenex” out the window expecting a change in direction down here at 1g... ;D
"The laws of physics are unforgiving"

Offline deltaV

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How about towing behind an F15 or F15E for high altitude tests? Those fighters seem to be about the right size for towing Dream Chaser and their insane T/W would make reaching the needed takeoff speed within a reasonable length runway easy.

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