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#31
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Time to Think ?Horizontal? for Future Space Launches
On Sep 23, 4:02*pm, Pat Flannery wrote:
On 9/23/2010 4:51 AM, Jeff Findley wrote: True. *Any way it was tried, the "tail sitter" mode of landing was just too dangerous to proceed to an operational vehicle. You could do it nowadays relying on GPS and automated landing control; Correct. but trying to land something as big and light as a ET in a side wind would be pure folly. Nonsense. The Coleoptere had one advantage over the Pogo and Lockheed "Salmon"; in it the pilot could pivot his seat ninety degrees so he ended up sitting upright and looking out a window in the bottom of the aircraft's nose during landing. Correct. One of the big problems in the Pogo was that the pilot couldn't tell how fast he was ascending or descending in vertical flight other than looking at the altimeter or a "wind vane" mounted on the wingtip that would at least tell him if he was rising or descending. Yep. The big problem was that if it started descending too fast the aircraft was going to tip over sideways under the influence of the wings going backwards into the airstream, and end up doing a power dive straight into the ground. Yet, none were lost this way. We can thank the Germans for coming up with this goofy idea:http://www.luft46.com/heinkel/hewesp...w/fwtrieb.html Its not goofy - especially in a rocket that takes off vertically. Today, vertical landing with the aircraft in the horizontal position is preferred (e.g. Harrier, V-22 Osprey, and pretty much every operational helicopter). *This eliminates the 90 degree rotation required by a tail sitter which eliminates the requirement for the pilot to guide the craft down with his back to the ground and his eyes pointed up at the sky. Moot for an unpiloted vehicle. The VTOL aspect of the Coleoptere was only the start of the fun; it was going to come flying out of a silo in the ground, and once in horizontal flight the space between the circular wing and fuselage was going to turn into a ramjet...like I said, the thing was straight out of "Thunderbirds". This is over-kill for what I am proposing to do. I've got Mook killfiled, so I'm only reading what you quote from him. Is there some reason that he wants it to land vertically rather than just glide-land with the inflatable wings? Sure, eliminate the weight of landing gear and the weight of all the structure needed to sustain a horizontal landing. The weight of propellant needed to climb into vertical position and land as a DC-X or LEM - using the same structure for the hold-down clamps as points of contact for landing - requires far less parasitic weight. If you are going to land it vertically, all you need to do is stick some parachutes in the nose and have the weight of the rear plug-nozzle engine make it fall tail-first towards the landing site. Once you are in vertical position you land using rockets DC-X fashion. There's no need for the goofy wings then. Fold away wings aren't goofy. They're used in other unpiloted vehicles that launch vertically and transition to horizintal flight - the Tomahawk Cruise Missile for example. The wings are needed for downrange recovery using a tow plane. The tow plane then brings the glider back to the launch center and releases it. The landing engines start the vehicle climbs to vertical and then lets down on a mobile landing platform. The vehicle is then processed to be relaunched in as little as 24 hours. In that case what you end up with is very similar to the SASSTO Saturn IVB stage, with the plug nozzle serving as the heatshield:http://www.up-ship.com/drawndoc/sdoc53ani.jpg Correct. SASSTO Saturn IVB was a point of study for my design. I did not want to do single stage to orbit or have the booster vehicle land downrange. Hence the fold-away wing system. Pat |
#32
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Time to Think ?Horizontal? for Future Space Launches
On Sep 23, 9:07*am, Jeff Findley wrote:
In article 656fdf76-a183-4975-895c- , says... On Sep 22, 11:57*pm, Fred J. McCall wrote: William Mook wrote: My system uses an inflatable thermal protection system to slow below sonic speeds and fold away wings when gliding below the speed of sound. * A tow plane flying down-range snags the booster as it is gliding down-range with a tow line and tows it back to the launch center. *There the booster is released. *The engine re-starts at a low thrust setting, as the booster climbs into vertical position. *It then settles down tail first, like the old tail sitters from the 1950s - on a mobile landing platform. *The wings and thermal systems retract and the booster is readied for another launch. And all you need is a few thousand tons of unobtanium to go with your handwavium and you'll be able to implement your crayon drawings. Nonsense You're the one making extraordinary claims. *You have yet to provide the extraordinary proof required. Jeff -- The only decision you'll have to make is Who goes in after the snake in the morning? What is so extraordinary about a rocket that takes off vertically? About parallel staging of an ET? About annular aerospike engines? About an inflatable thermal protection system that protects an ET airframe during re-entry? About fold-away wings that allow a rocket to transition to a glider? About down-range recovery of a glider by a tow plane pre-positioned at the down-range location? About towing a glider back to the launch center? About releasing a glider and having it start a landing engine and transition to tail sitting mode? About landing a rocket on its tail? On a mobile platform? ALL OF THESE THINGS HAVE BEEN DONE AT ONE TIME OR ANOTHER - so, you explain to me what's so extraordinary about any of them? |
#33
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Time to Think ?Horizontal? for Future Space Launches
On Sep 23, 10:43*am, Fred J. McCall wrote:
William Mook wrote: On Sep 22, 11:57*pm, Fred J. McCall wrote: William Mook wrote: My system uses an inflatable thermal protection system to slow below sonic speeds and fold away wings when gliding below the speed of sound. * A tow plane flying down-range snags the booster as it is gliding down-range with a tow line and tows it back to the launch center. *There the booster is released. *The engine re-starts at a low thrust setting, as the booster climbs into vertical position. *It then settles down tail first, like the old tail sitters from the 1950s - on a mobile landing platform. *The wings and thermal systems retract and the booster is readied for another launch. And all you need is a few thousand tons of unobtanium to go with your handwavium and you'll be able to implement your crayon drawings. Nonsense No need for you to sign your posts. *We know what your output is. -- "Ordinarily he is insane. But he has lucid moments when he is *only stupid." * * * * * * * * * * * * * * -- Heinrich Heine Stop it Freddie. |
#34
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Time to Think ?Horizontal? for Future Space Launches
On Sep 23, 8:46*am, Jeff Findley wrote:
In article d82da96a-39ad-47b2-915d-c97befe360f8 @x18g2000pro.googlegroups.com, says... I agree, Jeff Pat and Fred are damn annoying and rude. *My comment was relevant to the horizontal take off and landing statement. *I don't see how that can be annoying and rude. It wasn't relevant. *Your napkin drawing takes off vertically and ultimately lands vertically. *It is not a horizontal take off and horizontal landing vehicle, so your post was a clear thread-jack. Jeff -- The only decision you'll have to make is Who goes in after the snake in the morning? Nonsense. The Air Force released a study pointing out that horizontal landing and take off adds significantly to structure fractions for a multi-stage orbiter. I provide a counter example that shows VTOVL launch elements parallel staged makes more sense. |
#35
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Time to Think ?Horizontal? for Future Space Launches
On Sep 23, 11:48*am, Fred J. McCall wrote:
Jeff Findley wrote: In article d82da96a-39ad-47b2-915d-c97befe360f8 , says... I agree, Jeff Pat and Fred are damn annoying and rude. *My comment was relevant to the horizontal take off and landing statement. *I don't see how that can be annoying and rude. It wasn't relevant. *Your napkin drawing takes off vertically and ultimately lands vertically. *It is not a horizontal take off and horizontal landing vehicle, so your post was a clear thread-jack. Careful, Jeff. *He's going to start threatening you soon... -- "Ordinarily he is insane. But he has lucid moments when he is *only stupid." * * * * * * * * * * * * * * -- Heinrich Heine Stop it Freddie. |
#36
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Time to Think Horizontal for Future Space Launches
In message
Doug Freyburger wrote: Pat Flannery wrote: Doug Freyburger wrote: It's just like the mountain based rail launcher on the old puppet show Fireball XL-5! I liked that show just as much as All Thunderbrids Are Go. I always wanted to see the far side of that mountain where the hundreds of JATO booster sleds lay, rusting slowly away. I figure the version of Cheyanne Mountain from "The Moon is a Harsh Mistress" was on the othe side - There is no Cheyanne Mountain. "No boom today. Boom tomorrow. There's always a boom tomorrow". "This is wrong" quote ... I'm not sure if it was ever clear in the TV episodes, but in the comic stories Space City was on an island so the other side of the mountain may well be a wet bit with the sleds being towed back to the start of the track. Anthony |
#37
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Time to Think ‘Horizontal’ for Future Space Launches
On 24/09/2010 5:24 AM, Pat Flannery wrote:
On 9/23/2010 1:15 AM, Sylvia Else wrote: Thing is, you need a structure strong enough to tolerate the aerodynamic forces of whatever speed the launch rail gives at its end point, but then you need to carry that structure to up to where the second stage is released, or orbit if you're going for SSTO. ...and God help you if there's a rabbit or rock sitting on that track considering how fast you are going to be going down it on the launch sled. You note whenever they show drawings of these things, they seem to throw in a tunnel it's going to pass through before it reaches the end of the track: http://www.g2mil.com/argus2.jpg I don't know if that's just for effect, or if it's supposed to serve some purpose - I had the thought that the tunnel might have thin sheets of plastic on either end and be pumped full of pure oxygen to help light the scramjets as the vehicle pierces the plastic walls on launch. Pat I think the tunnel is just to add another aerodynamic effect, so as to make things more complicated. Otherwise it's much to easy. Sylvia. |
#38
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Time to Think Horizontal for Future Space Launches
On 9/23/2010 1:32 PM, Anthony Frost wrote:
I'm not sure if it was ever clear in the TV episodes, but in the comic stories Space City was on an island so the other side of the mountain may well be a wet bit with the sleds being towed back to the start of the track. I guess that's a possibility; I went looking around on YouTube to see if they had any clips of what exactly happens to the sled, but it appears they used pretty much the same footage for every launch. BTW, for anyone who hasn't seen it, Peter Cook and Dudley Moore with the brilliant puppetoons parody "Superthunderstingcar": http://www.youtube.com/watch?v=PEdIP1qfONw Pat |
#39
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Time to Think ‘Horizontal’ for Future Space Launches
On 24/09/2010 2:22 PM, Fred J. McCall wrote:
Sylvia wrote: On 24/09/2010 5:24 AM, Pat Flannery wrote: On 9/23/2010 1:15 AM, Sylvia Else wrote: Thing is, you need a structure strong enough to tolerate the aerodynamic forces of whatever speed the launch rail gives at its end point, but then you need to carry that structure to up to where the second stage is released, or orbit if you're going for SSTO. ...and God help you if there's a rabbit or rock sitting on that track considering how fast you are going to be going down it on the launch sled. You note whenever they show drawings of these things, they seem to throw in a tunnel it's going to pass through before it reaches the end of the track: http://www.g2mil.com/argus2.jpg I don't know if that's just for effect, or if it's supposed to serve some purpose - I had the thought that the tunnel might have thin sheets of plastic on either end and be pumped full of pure oxygen to help light the scramjets as the vehicle pierces the plastic walls on launch. I think the tunnel is just to add another aerodynamic effect, so as to make things more complicated. Otherwise it's much to easy. Why not go with Pat's idea, but postulate a light gas gun or vacuum tube to let the vehicle avoid air drag until it is up to speed? It depends which problem one is trying to solve. As I understand the point of these rail-launch mechanisms, it's that the energy required for the initial acceleration doesn't have to be contained in fuel carried by the vehicle, thus reducing the mass of the latter. But it also means that drag losses while the vehicle is on the launcher are not such an issue - you just build a powerful enough launcher. But no matter how the vehicle is accelerated, sooner or later it has cope with the air at the end of the launcher. If it's not strong enough, it will come apart. Putting the vehicle in a tube, whether in a lighter gas, or a vacuum, just means it has to handle a transient in the transition to flight in the air as well. Sylvia. |
#40
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Time to Think ‘Horizontal’ for Future Space Launches
On 9/23/2010 10:40 PM, Sylvia Else wrote:
It depends which problem one is trying to solve. As I understand the point of these rail-launch mechanisms, it's that the energy required for the initial acceleration doesn't have to be contained in fuel carried by the vehicle, thus reducing the mass of the latter. But it also means that drag losses while the vehicle is on the launcher are not such an issue - you just build a powerful enough launcher. Yeah the concept is to make something like a ground-mounted first stage that can use electrical energy (stored up in huge capacitors, I imagine) instead of solid or liquid fuel; one advantage you get is once the spacecraft comes off the sled, you can reverse the polarity of the magnetic fields and use them to slow the launch sled back down (if you could get really clever about that, you could turn the decelerating sled into a homopolar generator and regain a lot of the electrical energy you used for launch, sending it into the capacitors again. One problem is the length of track needed to get the launch sled up to the desired speed without squishing the astronauts from excessive G forces. Sandia was looking into designing unmanned satellites that could take very high G loads and firing them up to 15,000 mph in a electromagnetic rail gun, leaving them only needing to add around 3,000 mph of their own with a attached rocket to reach orbit (actually the added speed needed to reach orbit would be higher, due to air drag slowing the projectile down as it went through the lower atmosphere). That was also the final aim of Gerald Bull's HARP cannon system, that would use conventional explosives to do the same thing. Both of these ideas are probably workable if you threw enough effort at them, although heating on the projectile will be very severe as it begins its ascent. But no matter how the vehicle is accelerated, sooner or later it has cope with the air at the end of the launcher. If it's not strong enough, it will come apart. Putting the vehicle in a tube, whether in a lighter gas, or a vacuum, just means it has to handle a transient in the transition to flight in the air as well. The shockwave coming off a good-sized vehicle as it's accelerated to multi-Mach speed on the launch track wouldn't be anything to sneeze at either - at close range it would be literally lethal. As an alternative to electrical power, steam has been suggested as a power source to drive the launch sled, as seen in this 1960's Lockheed rail-launched concept that would use the track to do initial acceleration on a three stage fully-reusable space launch system: http://dreamsofspace.nfshost.com/gif...gstations7.jpg Another approach was to mount propellant tanks in the launch sled that feed the spacecraft's own engines to accelerate it, so that it still has full tanks on reaching the lift-off point on the launch track. Certainly a lot simpler than doing it via maglev rail systems. That's how 1968's Hyperion was to be launched: http://www.astronautix.com/lvs/hypnssto.htm Pat |
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