"SpaceShipTwo could be single stage to SUBorbit"
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From: Robert Clark on 14 May 2010 09:47 On May 13, 6:50 pm, Pat Flannery <flan...(a)daktel.com> wrote: > On 5/13/2010 9:10 AM, LSMFT wrote: > > > > >> "... the UK firm came to the conclusion that the volume within which > >> SS2 carries its solid rocket motor and nitrous oxide supply could > >> equally hold a liquid chemical propulsion system capable of providing > >> enough thrust for long enough for a horizontal take-off and ascent to > >> 50,000ft and above without the need for WK2." > >>http://www.flightglobal.com/blogs/hyperbola/2010/04/spaceshiptwo-coul.... > > >> If you also filled up the passenger compartment with fuel leaving only > >> a pilot's cabin could it even become orbital? > > >> Bob Clark > > > What happened to the X-30? > > And since when did 50,000 feet become outer space? > I like the part about it using a "liquid chemical propulsion system", > without specifying what those chemicals are exactly. > You could certainly make a ground takeoff rocket plane that could climb > to 50,000 feet, but since numerous types of jet aircraft are capable of > flying to 50,000 feet also, what would be the point of doing this? > > Pat The article mentions "50,000 ft and above". But to do suborbital flights means above the sensible atmosphere and a longer time for the period of weightlessness. The author Rob Coppinger may have given the 50,000 ft. number to remind the reader of the altitude WhiteKnightTwo reaches. I'll ask him about that. Bob Clark
From: J. Clarke on 14 May 2010 10:59 On 5/14/2010 9:08 AM, Greg D. Moore (Strider) wrote: > J. Clarke wrote: >> On 5/13/2010 11:12 PM, Greg D. Moore (Strider) wrote: >>> J. Clarke wrote: >>>> >>>> Scramjets work. Get used to it. >>> >>> Really? How many flight hours do they have? >> >> Enough to show that they work. >> >>> How many have been flown more than once? >> >> Enough to show that they work. > > Umm, really? I don't know of any that have flown for more than a few > minutes at my most recent research didn't reveal any that were reflown. So how many Saturn Vs flew more than a few minutes and how many were reflown? I guess they don't work either. > But as you seem to know, perhaps you can point me to the ones that have > flown for hours. And the ones that have reflown. Straw man.
From: J. Clarke on 14 May 2010 10:58 On 5/14/2010 9:10 AM, Greg D. Moore (Strider) wrote: > J. Clarke wrote: >> On 5/13/2010 11:14 PM, Greg D. Moore (Strider) wrote: >>> J. Clarke wrote: >>>>> X-30 was way too much for NASA to do in one huge leap and would >>>>> have required billions more dollars just to try to make it work. The >>>>> state of the art in hypersonic propulsion still isn't where it >>>>> would need to be to build X-30 today (note that X-30 was cancelled >>>>> more than two decades ago). Hypersonic propulsion is one of those >>>>> promising looking technologies that's been "only a few years away" >>>>> for many decades. >>>> >>>> Uh, it's not there because Clinton pulled the plug on it. >>> >>> Really? Amazing. I didn't realize Clinton whas that powerful. You >>> mean no one else was capable of doing research on Hypersonic >>> propulsion? >> >> Nobody is capable of doing any kind of research on anything unless >> somebody is willing to put food on their table while they're doing it. >> >>> Hypersonic propulsion was " a few years away" before Clinton and is >>> still a few years away. >> >> So where would it be if development had been continued instead of >> being stopped and restarted again a decade or so later? > > Again, it wasn't stopped worldwide. Clinton wasn't that powerful. > > Other countries DID do research and development in the meantime. So who was putting the same kind of money into it that NASA had been? > Or are you saying only R&D in the US is applicable? Who else has the economic resources of the US?
From: Jeff Findley on 14 May 2010 11:03 "J. Clarke" <jclarke.usenet(a)cox.net> wrote in message news:hshuh912r54(a)news1.newsguy.com... > On 5/13/2010 4:04 PM, Jeff Findley wrote: >> "Pat Flannery"<flanner(a)daktel.com> wrote in message >> news:6vGdnRW146eIxXHWnZ2dnUVZ_tOdnZ2d(a)posted.northdakotatelephone... >>> On 5/13/2010 9:10 AM, LSMFT wrote: >>>> What happened to the X-30? >>> >>> And since when did 50,000 feet become outer space? >>> I like the part about it using a "liquid chemical propulsion system", >>> without specifying what those chemicals are exactly. >>> You could certainly make a ground takeoff rocket plane that could climb >>> to >>> 50,000 feet, but since numerous types of jet aircraft are capable of >>> flying to 50,000 feet also, what would be the point of doing this? >> >> The promises made by X-30 were absolutely silly, in retrospect. A >> vehicle >> which can cruise at hypersonic speeds is going to be very different than >> a >> vehicle which can accelerate to orbital speeds, yet somehow X-30 was >> being >> sold as able to do both (makes me think of the SNL skit for Shimmer, a >> floor >> polish and a dessert topping). > > So let's see, a vehicle that can cruise at Mach 20 is going to be > different from one that can accelerate to Mach 25 how, exactly? > >> The fact of the matter is that LOX and liquid fueled rocket engines are >> really good at accelerating vehicles to orbital velocity. > > No, actually they aren't. They can do it, but "really good"? No. Show me an air breather that can do better. Better yet, show me an air breather which can actually fly at Mach 20, which is what NASP was sold as being able to do. >> Air breathers, >> not so much. The machinery required to compress enough air for use in an >> engine optimized for rocket like acceleration would be large and heavy. >> So >> much so that just bringing your own LOX in a tank turns out to be a net >> win. > > X-30 was intended for Mach 20 cruise. At Mach 20 orbit isn't that far > away. But you can't get there with air breathing engines. You *must* switch to engines burning oxidizer carried on board. Now you're talking about two different sets of engines to maintain. Either that or you're talking an even *more* complicated engine that can do both. Considering that we have yet to develop a hypersonic air breathing engine without a rocket mode, this is a stretch, to say the least. > You don't need "rocket like acceleration" if you are cruising at speeds > that high. > > And you don't need any "large and heavy machinery" to "compress enough > air". > > Scramjets work. Get used to it. B.S. Scramjets are a research project, not an off the shelf commercial technology. Anyone who tells you otherwise is selling you snake oil. On the other hand, liquid fueled rocket engines suitable for use in orbital launch vehicles have been available since the late 1950's. They are off the shelf technology today. There is no shortage of companies today which will sell you fully developed liquid fueled rocket engines which are currently being used on existing launch vehicles. Jeff -- "Take heart amid the deepening gloom that your dog is finally getting enough cheese" - Deteriorata - National Lampoon
From: Jeff Findley on 14 May 2010 11:09
"Greg D. Moore (Strider)" <mooregr_delet3th1s(a)greenms.com> wrote in message news:kPidnSF_YbM213DWnZ2dnUVZ_gGdnZ2d(a)earthlink.com... > J. Clarke wrote: >> On 5/13/2010 11:12 PM, Greg D. Moore (Strider) wrote: >>> J. Clarke wrote: >>>> >>>> Scramjets work. Get used to it. >>> >>> Really? How many flight hours do they have? >> >> Enough to show that they work. >> >>> How many have been flown more than once? >> >> Enough to show that they work. > > Umm, really? I don't know of any that have flown for more than a few > minutes at my most recent research didn't reveal any that were reflown. You're being very generous. I'd say there have not been any flown for more than a few seconds and shown to be producing positive thrust at hypersonic speeds. And this is just *one* design point. Those test engines were boosted to their test speed by *rocket engines*. Aerospace engineers are a *long* way from producing a hypersonic air breathing engine which can operate from a runway to Mach 20, which is what NASP was aiming for. > But as you seem to know, perhaps you can point me to the ones that have > flown for hours. And the ones that have reflown. Obviously he can't because they don't exist. And even if he was one of those people who claim they do exist as a secret military technology, that's not the same as "off the shelf" commercial technology which could be used in a next generation launch vehicle. Jeff -- "Take heart amid the deepening gloom that your dog is finally getting enough cheese" - Deteriorata - National Lampoon |