SCRAM jet + linear aerospike LV

[propforce]

<i>"... Or jettoson the jet. .."</i><br /><br />Hey, a Liquid Flyback Booster .... what an idea !!! <img src="/images/icons/laugh.gif" /> <div class="Discussion_UserSignature"> </div>

 

[propforce]

<i> ".... flying a craft within the atmosphere at Mach 20 would produce how much heating? ..."</i><br /><br />Lots and lots ... and LOTS of heat !!! Those heat must be removed by active cooling, e.g., using fuel to draw heat away from the airframe like a heat exchanger.<br /><br />The trouble is, it would require more fuel for cooling than the amount of fuel for scramjet combution. <br /><br />Development in advanced materials may reduce this cooling requirements. <div class="Discussion_UserSignature"> </div>

 

[propforce]

Awww... the smell of Jet-A in the morning !!! <div class="Discussion_UserSignature"> </div>

 

[scottb50]

Either way it becomes a trade-off. More mass in engines or more mass in propellant. Eight or nine minutes with a rocket or 20-30 with a combination of propullsion systems to get to oibit.<br /><br />Then you have to think of what the upper limit of a Sramjet would be, Mach12-15? If inlet changes are needed from Mach 7 to Mach10 then it gets even more complicated going faster, and like you say there is the heating factor.<br /><br />I still think the bute force method used now is the best alternative to orbit and the second best is a rocket powered first stage return vehicle with an upper stage. Jet engtines, ramjets, scramjets only complicate matters way more then they help. <div class="Discussion_UserSignature"> </div>

 

[eric_apollo]

Subject: User Name: Mental_Avenger<br /><br />To Whom It May Concern,<br /><br />The above person, user name Mental_Avenger has continued to purposely spread lies and disinformation about the International Space Agency and Mr. Rick Dobson.<br /><br />This person has taken a number of user names on Space.Com and on other Space Message Boards, to spread their lies and disinformation.<br /><br />This person has, and is, working either with, or on the behalf of, some unknown organization or group that has been conducting a focused smear and propaganda campaign now for a number of years against the International Space Agency and Mr. Rick Dobson.<br /><br />This person has been baiting people, and entering posts which the International Space Agency has made, with the "specific purpose" of slandering, causing trouble, and spreading lies & disinformation. And to specifically disrupt and derail these positive posts, and to chase people away. This persons malicious and vindictive actions have been constant and very threatening.<br /><br />We are asking that these slanderous and illegal acts be stopped, and that we obtain the personal information of this person for legal action for criminal defamation of character and slander, and to report this person to Law Enforcement for making terroristic threats against the Chairman & CEO of the International Space Agency, Mr. Rick Dobson. This person "Mental_Avenger" has been making a number of terroristic threats against the Chairman & CEO of the International Space Agency, Mr. Rick Dobson.<br /><br />The International Space Agency or Mr. Dobson has never done anything wrong on Space.Com, and has never been anything less than positive, or has presented anything other than uplifting and factual information to the Space.Com community and posting board.<br /><br />It is criminal to allow this person "Mental_Avenger" to defame, smear, and attack legitimate organizations and people with impunity. This is not a freedom of speech issue, as th

 

[elguapoguano]

deleted <div class="Discussion_UserSignature"> <font color="#ff0000"><u><em>Don't let your sig line incite a gay thread ;>)</em></u></font> </div>

 

[starfhury]

The ISP design is very similar to what I was thinking. I will have to check out your site and the other thread. I do notice everyone ignoring the aerospike engine in the discussing as means of launching and accellerating the LV to SCRAM jet speeds. As side from propellant consumption, is there some other reason making the SCRAM jet / aerospike engine insufficient to the task? <div class="Discussion_UserSignature"> </div>

 

[propforce]

Does this thing takes off vertically or horizontally? <br /><br />It makes a big difference in structural margin if it's a horizontal take-off. If it's a vertical take off, then pitching over to horizontal can also stress the airframe severely. <br /><br />The virtue of aerospike engine is altitude compensation. It does not make sense if it'll mainly be used as high altitude engine. Aerospike engines will also have less life than conventional bell-nozzle engines, which means you'll need to replace them more often which will affect your cost and logistics. <br /><br />But the main advantage of aerospike engine is integration. It makes a nice flat exit profile that fits in with vehicle shape and scramjet nozzle. Differential throttling also will (in theory) reduce the wing control surfaces area required. Although the X-33 wings seem to get bigger and bigger as design matures.<br /><br />An alternate design would be to put aerospike engine <i>inside of scramjet engine</i>, this way they both share the same nozzle. <img src="/images/icons/cool.gif" /> <div class="Discussion_UserSignature"> </div>

 

[rogers_buck]

Nice thing about taking off horizontally, is that you can take-off empty. Aerial refueling is well understood technology.<br /><br />The nice thing about a scram jet is that there is no need for the oxidizer. That is a considerable savings in mass.<br /><br />Practical issues in developing these advantages are considerable.<br /><br />What are realistic upper limits for dry take-off weight, and fully fueled airborne weight in terms of structural design constraints. Can you make a carrier that could lift a 100,000lb payload+booster from the runway and still have that system flyable with an additional 200,000+ lbs of fuel? <br /><br />If so, would such a carrier be able to go Mach 2+? No current examples of a jet based aircraft with these credentials exists.<br /><br />Someone suggested a flying wing as the best configuration for lift and performance in a thread discussing the Antanov launcher. Would a flying wing have to be a flying delta-wing to hit Mach 2.5? Would the "second stage" scramjet vehicle have to be a lifting body to offset the additional weight after refueling with lift?<br /><br />Using the B-1 program as a model for the jet stage the price tag would be billions for development.<br /><br />Can a scramjet be scaled large with adaquate thrust and thermal characteristics to accelerate to Mach 20+ in the high atmosphere? What would the upper limit for such a design be given the constraints imposed on the first stage?<br /><br />Assuming this is all positive, I think the Space Shuttle is a good estimator for the cost of a project like the above orbiter (maybe x4).<br /><br />The scram jet and jet launcher seem like they will be far too costly to ever get funded. On the large scale needed as a heavy lifter/manned launch system. Seems like it might have a good niche as a low-mass to orbit reuseable launch system though building on the X-43C.<br /><br />I think big old smokey rockets will rule the high-ground for a long, long, time.<br />

 

[international_space_agency_org]

Space Planes From Around The World - A Journey In Pictures:<br /><br />http://p201.ezboard.com/finternationalspaceagencyfrm10.showMessage?topicID=39.topic<br /><br />Very Nice! Great Pictures!

 

[propforce]

Yes aerial refueling is a well understood technology .... for jet fuel. Aerial "refueling" for liquid oxygen is considered a dangerous and unproven technology, it is more dangerous than refueling liquid hydrogen eventhoug LH2 is some 100 deg. colder than LO2.<br /><br />It is true that scramjet's advantage is that there's no need for the oxidizer, however; because it also has no <i>mechanical compression of incoming air</i>, it has a relatively low chamber pressure therefore produce low thrust. <br /><br />Up till the recent X-43A test, many have openly question if a ramjet/ scramjet can be used for acceleration.<br /><br />The disadvantage of a fully loaded aircraft that takes off horizontally is that 1) the landing gears must be sized to withstand those weight, 2) relatively large wing span to increase lift. A horizontal take-off "space-craft" suffer the same disadvantage but worse. The landing gear weight must be carried all the way to orbit and back. The large wing-span required for take-off lift and for subsonic flight, will need to be swept-back in supersonic speed to reduce shock wave and aerodynamic drags. Realistically the entire wing should disappear when the scramjet kick in the hypersonic speed (above Mach 4). How to "morph" the wings into disappearing presents a mechanical challenge, so designers live with the penalty of having wings above hypersonic speed.<br /><br />Many have studied various launch-assist methods, and designing for one to launch a 100,000 lbm is not a problem, but designing one to launch at above Mach one at sea level would present multiple problems. It would be far easier to launch at some slower speed, e.g., 200 mph, and have the vehicle's onboard propulsion system to accelerate to supersonic speed such as Mach 2.5 before the ramjet kicks in. <br /><br />The question is then, what does one use for low speed propulsion? The most obvious answer is turbojet engines. But the turbojet engines are very heavy, and complex. In addition, <div class="Discussion_UserSignature"> </div>

 

[rogers_buck]

>> Yes aerial refueling is a well understood technology .... for jet fuel. Aerial "refueling" for liquid oxygen is considered a dangerous and unproven technology, it is more dangerous than refueling liquid hydrogen eventhoug LH2 is some 100 deg. colder than LO2. <br /><br />I was thinking of a concept not unlike White Night where the Space Ship 1 analog was scramjet powered. So the aerial refueling would be only jet fuel and scramjet fuel.<br /><br /> />> The disadvantage of a fully loaded aircraft that takes off horizontally is that 1) the landing gears must be sized to withstand those weight, 2) relatively large wing span to increase lift. A horizontal take-off "space-craft" suffer the same disadvantage but worse. The landing gear weight must be carried all the way to orbit and back. The large wing-span required for take-off lift and for subsonic flight, will need to be swept-back in supersonic speed to reduce shock wave and aerodynamic drags. Realistically the entire wing should disappear when the scramjet kick in the hypersonic speed (above Mach 4). How to "morph" the wings into disappearing presents a mechanical challenge, so designers live with the penalty of having wings above hypersonic speed. <br /><br />Morphing for hyper-sonic flight is avoided if the airplane bits return to the airport.<br /><br />The White Night analog would have to be able to not only takeoff with the 100,000lb mass but would have to accelerate with turbo-jet/ram-jet to Mach 2.5. It would have to do this with a 300,000 Space Ship1 analog mated to it. The Space Ship 1 analog would be the scram jet stage and could be wingless as you suggest. It would likely need to generate sufficient lift to offset the fuels weight after refueling. The White Night wouldn't go into orbit so the engine mass and landing gear wouldn't go any farther than 50,000 ft. <br /><br />It seems that a further advantage of scramjets is that they should be discardable. That is to say, designed for a single missi