RobertFisher
SOC-12
When you've got antigravity technology, why is streamlining necessary for a ship to land on a planet with an atmosphere?
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Robert FISHER
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Robert FISHER
Why is streamlining necessary?
- Thread starter RobertFisher
- Start date
I'll take a shot:
1) With contra-grav thursters the ship could conceivably float like a feather down, providing the G rating is one higher then the planet... putting the average at two, and a safer need at three. Anything else would have to come in like the Space-shuttle (i.e streamlined).
2) Also, streamlining allows for a glide motion, allowing the ship to come in with better control as the bumps and ridges of a non-streamlined would catch the varios eddies and currents of the atmosphere and require a more complicated piloting. it is easier to pilot a craft with a form that is understood in the laws of aerodynmaics then one that is a very complex surface....unless you go REAL slow.
Gats'
1) With contra-grav thursters the ship could conceivably float like a feather down, providing the G rating is one higher then the planet... putting the average at two, and a safer need at three. Anything else would have to come in like the Space-shuttle (i.e streamlined).
2) Also, streamlining allows for a glide motion, allowing the ship to come in with better control as the bumps and ridges of a non-streamlined would catch the varios eddies and currents of the atmosphere and require a more complicated piloting. it is easier to pilot a craft with a form that is understood in the laws of aerodynmaics then one that is a very complex surface....unless you go REAL slow.
Gats'
<BLOCKQUOTE>quote:</font><HR>Originally posted by Gatsby:
I'll take a shot:
1) With contra-grav thursters the ship could conceivably float like a feather down, providing the G rating is one higher then the planet... putting the average at two, and a safer need at three. Anything else would have to come in like the Space-shuttle (i.e streamlined).
2) Also, streamlining allows for a glide motion, allowing the ship to come in with better control as the bumps and ridges of a non-streamlined would catch the varios eddies and currents of the atmosphere and require a more complicated piloting. it is easier to pilot a craft with a form that is understood in the laws of aerodynmaics then one that is a very complex surface....unless you go REAL slow.
Gats'<HR></BLOCKQUOTE>
That sounds about right to me. You'd only need the same G to land on a planet, you'd need one higher to take off
The wind speeds in atmosphere are very high and an unstreamlined ship would burn up even if it decended at a very slow speed.
J.
I'll take a shot:
1) With contra-grav thursters the ship could conceivably float like a feather down, providing the G rating is one higher then the planet... putting the average at two, and a safer need at three. Anything else would have to come in like the Space-shuttle (i.e streamlined).
2) Also, streamlining allows for a glide motion, allowing the ship to come in with better control as the bumps and ridges of a non-streamlined would catch the varios eddies and currents of the atmosphere and require a more complicated piloting. it is easier to pilot a craft with a form that is understood in the laws of aerodynmaics then one that is a very complex surface....unless you go REAL slow.
Gats'<HR></BLOCKQUOTE>
That sounds about right to me. You'd only need the same G to land on a planet, you'd need one higher to take off
The wind speeds in atmosphere are very high and an unstreamlined ship would burn up even if it decended at a very slow speed.
J.
RobertFisher
SOC-12
<BLOCKQUOTE>quote:</font><HR>Originally posted by J:
The wind speeds in atmosphere are very high and an unstreamlined ship would burn up even if it decended at a very slow speed.<HR></BLOCKQUOTE>
You mean the wind speeds in the upper part of the atmosphere? Obviously high wind speeds don't burn up many unstreamlined structures on the ground.
In any case, why couldn't you just match the wind's vector to negate this?
Are open top air rafts considered streamlined? If not, why can they enter and leave the atmosphere but a ship can't?
I'm willing to accept that safe atmospheric entry for a unstreamlined ship takes longer than for a streamlined ship. (Just as an air raft takes a long time to reach orbit from the ground.)
I'm willing to accept that the typical maneuver drives on a ship are something quite different from whatever drives an air raft, and that an unstreamlined ship that wanted to act like a big air raft would need to specifically be designed with such air raft-ish drives in addition to conventional ship drives.
I'm also willing to accept that the conditions of the upper atmosphere are such that entry without streamlining is nigh impossible, but it's going to have to be a convincing argument, and I have a hard time imagining how it wouldn't apply to open top air rafts as well.
[Edited for typos...]
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Robert FISHER
[This message has been edited by RobertFisher (edited 19 June 2001).]
The wind speeds in atmosphere are very high and an unstreamlined ship would burn up even if it decended at a very slow speed.<HR></BLOCKQUOTE>
You mean the wind speeds in the upper part of the atmosphere? Obviously high wind speeds don't burn up many unstreamlined structures on the ground.
In any case, why couldn't you just match the wind's vector to negate this?
Are open top air rafts considered streamlined? If not, why can they enter and leave the atmosphere but a ship can't?
I'm willing to accept that safe atmospheric entry for a unstreamlined ship takes longer than for a streamlined ship. (Just as an air raft takes a long time to reach orbit from the ground.)
I'm willing to accept that the typical maneuver drives on a ship are something quite different from whatever drives an air raft, and that an unstreamlined ship that wanted to act like a big air raft would need to specifically be designed with such air raft-ish drives in addition to conventional ship drives.
I'm also willing to accept that the conditions of the upper atmosphere are such that entry without streamlining is nigh impossible, but it's going to have to be a convincing argument, and I have a hard time imagining how it wouldn't apply to open top air rafts as well.
[Edited for typos...]
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Robert FISHER
[This message has been edited by RobertFisher (edited 19 June 2001).]
<BLOCKQUOTE>quote:</font><HR>Originally posted by RobertFisher:
You mean the wind speeds in the upper part of the atmosphere? Obviously high wind speeds don't burn up many unstreamlined structures on the ground.
In any case, why couldn't you just match the wind's vector to negate this?
Are open top air rafts considered streamlined? If not, why can they enter and leave the atmosphere but a ship can't?
<HR></BLOCKQUOTE>
Yes I do mean the wind in the upper atmosphere. Even on the ground unstreamlined structures get damaged by the wind, think of an umbrella in high winds, then consider a communications dish on the side of a spaceship. Wind speeds in the upper atmosphere are much higher than on the ground so the effect is even worse.
Matching vectors with the wind would be difficult, but may help a little.
As for open topped air/rafts, i've never let them leave atmosphere because their unstreamlined.
In my games unstreamlined ships can land in an atmosphere, but they would have to expect quite of bit of damage on the way down. It's an emergency crash landing manuever.
J.
You mean the wind speeds in the upper part of the atmosphere? Obviously high wind speeds don't burn up many unstreamlined structures on the ground.
In any case, why couldn't you just match the wind's vector to negate this?
Are open top air rafts considered streamlined? If not, why can they enter and leave the atmosphere but a ship can't?
<HR></BLOCKQUOTE>
Yes I do mean the wind in the upper atmosphere. Even on the ground unstreamlined structures get damaged by the wind, think of an umbrella in high winds, then consider a communications dish on the side of a spaceship. Wind speeds in the upper atmosphere are much higher than on the ground so the effect is even worse.
Matching vectors with the wind would be difficult, but may help a little.
As for open topped air/rafts, i've never let them leave atmosphere because their unstreamlined.
In my games unstreamlined ships can land in an atmosphere, but they would have to expect quite of bit of damage on the way down. It's an emergency crash landing manuever.
J.
Myscha the sled dog
SOC-6
Air Friction Generates extreme temperatures.
Streamlining helps to channel air as a ship passes through itto control this.
Although CG, the shuttle re-entry scene in the movie Space Cowboys can give you an idea of how even with streamlining, the angle of approach and speed affects the friction with the atmosphere has on a ship hull and thus heat load on the exterior cladding of the ship.
Just my thoughts.
Streamlining helps to channel air as a ship passes through itto control this.
Although CG, the shuttle re-entry scene in the movie Space Cowboys can give you an idea of how even with streamlining, the angle of approach and speed affects the friction with the atmosphere has on a ship hull and thus heat load on the exterior cladding of the ship.
Just my thoughts.
<BLOCKQUOTE>quote:</font><HR>Originally posted by RobertFisher:
When you've got antigravity technology, why is streamlining necessary for a ship to land on a planet with an atmosphere?
<HR></BLOCKQUOTE>
It's not just the streamlining, but the structural bracing, the landing gear, etc, that USL's just don't have. Plus the retraction and stowage fixtures for anything that would catch winds, like antenae, arms, etc. And remember, hulls are designed to keep pressure in, not out, unless at least PSL.
CT and MT didn't have separate Contra-grav.
CT used Unstreamlined (USL), Partially Streamlined (PSL), and Fully Streamlined (FSL).
USL: No protection against winds, landing stresses, etc. You might be able to safely put down in a cradle; anything else is likely to compromise the hull integrity on landing. The high winds and often sudden shears will knock loose exterior fittings.
PSL: designed for powered atmosphereic operations only... not for landing, just for skimmin and dropping off VHAMO Chute-deployed packages, etc. The external dodad are retracctable, but it doesn't have landing gear, nor brace points. You might be able to put down in a lake or some other such medium, but not on solid ground... you'll compromise hull integrity.
FSL: You've got gear. You've got landing sensors. You've got all the other stuff is included in PSL. You've got enough hull integrity to ditch and maybe take off again.
MT and TNE assume USL can't make re-entry. Strealmined (SL) can and has lower atmospheric speed maximums than Airframe (AF). AF hulls get some areodynamic lift and have clean exteriors, for higher in atmosphere speeds. In short, an AF design can use same maneuver G as local world gravity... apply it as forward, until you are at speed, then appy enough up to clear, and as you get higher, more and more goes to up than forward...
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-aramis
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Smith & Wesson: The Original Point and Click interface!
When you've got antigravity technology, why is streamlining necessary for a ship to land on a planet with an atmosphere?
<HR></BLOCKQUOTE>
It's not just the streamlining, but the structural bracing, the landing gear, etc, that USL's just don't have. Plus the retraction and stowage fixtures for anything that would catch winds, like antenae, arms, etc. And remember, hulls are designed to keep pressure in, not out, unless at least PSL.
CT and MT didn't have separate Contra-grav.
CT used Unstreamlined (USL), Partially Streamlined (PSL), and Fully Streamlined (FSL).
USL: No protection against winds, landing stresses, etc. You might be able to safely put down in a cradle; anything else is likely to compromise the hull integrity on landing. The high winds and often sudden shears will knock loose exterior fittings.
PSL: designed for powered atmosphereic operations only... not for landing, just for skimmin and dropping off VHAMO Chute-deployed packages, etc. The external dodad are retracctable, but it doesn't have landing gear, nor brace points. You might be able to put down in a lake or some other such medium, but not on solid ground... you'll compromise hull integrity.
FSL: You've got gear. You've got landing sensors. You've got all the other stuff is included in PSL. You've got enough hull integrity to ditch and maybe take off again.
MT and TNE assume USL can't make re-entry. Strealmined (SL) can and has lower atmospheric speed maximums than Airframe (AF). AF hulls get some areodynamic lift and have clean exteriors, for higher in atmosphere speeds. In short, an AF design can use same maneuver G as local world gravity... apply it as forward, until you are at speed, then appy enough up to clear, and as you get higher, more and more goes to up than forward...
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-aramis
=============================================
Smith & Wesson: The Original Point and Click interface!
I can't quite buy grav and maneuver as being the same thing. They are clearly named differently and the design rules in High Guard and CT striker are incompatable. (We stopped building 100 ton grav tanks at higher TL: a 100 ton HG "gunboat"was faster, better armed and armored, and cheaper.)
A maneuver drive gives a constant thrust anywhere in the universe. In the '60s we would have called it an "advanced Dean-type drive." Today we can call it a "Mach's principle impulse drive" since Woodward had given that approach some legitimacy among physicists.
A grav drive produces thrust by interacting with local gravity. Thus, the grav drive of a 50 ton grav tank will produce 250 kilonewtons on a 0.5 G world and 500 kilonewtons on a 1 G world. At least, that is what I infer from there not being planetary limitations on grav vehicles. (Robert Forward has discussed how this is theoretically possible in Indistinguishable from Magic. NASA has a couple of research projects going to try to do it without storing the energy of a Gigaton bomb in every air-raft.)
As for streamlining, an unstreamlined ship can land on an airless world, so landing gear is not the problem. I generally assumed that safely landing an unstreamlined vessel required engines more powerful than local gravity and a piloting roll equal to the local atmosphere to match with the jetstreams, etc. Landing at low speed is tedious (a half hour or more), and a failed pilot roll can result in lost lunches to minor damage to a "hard" landing, through to complete destruction.
A hull that will keep 14.7 psi in will easily keep 3-4 psi out as well. You had better avoid atmospheres above 8, or infiltration and corrosion will damage the ship.
Streamlining is essential for gas giant refueling, and makes landing routine even for rookie pilots. Airframes . . . I never could figure airframes. Maneuver 2 was cheap enough, and a lot more useful. If top speed is a problem, climb out of the atmosphere and you can outrun any atmospheric craft.
I still say that a spaceship only needs wings and fins if the art director insists. But then, I objected to the VTOHL space shuttle in 1975 on the grounds that it was inefficient, and screamed bloody murder about the X-33 being a waste of effort and money back in 1996.
[This message has been edited by Uncle Bob (edited 20 June 2001).]
A maneuver drive gives a constant thrust anywhere in the universe. In the '60s we would have called it an "advanced Dean-type drive." Today we can call it a "Mach's principle impulse drive" since Woodward had given that approach some legitimacy among physicists.
A grav drive produces thrust by interacting with local gravity. Thus, the grav drive of a 50 ton grav tank will produce 250 kilonewtons on a 0.5 G world and 500 kilonewtons on a 1 G world. At least, that is what I infer from there not being planetary limitations on grav vehicles. (Robert Forward has discussed how this is theoretically possible in Indistinguishable from Magic. NASA has a couple of research projects going to try to do it without storing the energy of a Gigaton bomb in every air-raft.)
As for streamlining, an unstreamlined ship can land on an airless world, so landing gear is not the problem. I generally assumed that safely landing an unstreamlined vessel required engines more powerful than local gravity and a piloting roll equal to the local atmosphere to match with the jetstreams, etc. Landing at low speed is tedious (a half hour or more), and a failed pilot roll can result in lost lunches to minor damage to a "hard" landing, through to complete destruction.
A hull that will keep 14.7 psi in will easily keep 3-4 psi out as well. You had better avoid atmospheres above 8, or infiltration and corrosion will damage the ship.
Streamlining is essential for gas giant refueling, and makes landing routine even for rookie pilots. Airframes . . . I never could figure airframes. Maneuver 2 was cheap enough, and a lot more useful. If top speed is a problem, climb out of the atmosphere and you can outrun any atmospheric craft.
I still say that a spaceship only needs wings and fins if the art director insists. But then, I objected to the VTOHL space shuttle in 1975 on the grounds that it was inefficient, and screamed bloody murder about the X-33 being a waste of effort and money back in 1996.
[This message has been edited by Uncle Bob (edited 20 June 2001).]
The wind speeds in the upper atmosphere are indeed a lot higher. But the atmosphere is also thinner, resulting in less force.
I.E. a 100 MPH wind on the ground would require a 300 MPH wind in the upper atmosphere to generate the same force.
The space shuttle etc burn because it is their velocity that creates the friction, not the speed of the wind. If something were to come in slowly straight down then air friction would not be an issue. But gravity would.
I.E. a 100 MPH wind on the ground would require a 300 MPH wind in the upper atmosphere to generate the same force.
The space shuttle etc burn because it is their velocity that creates the friction, not the speed of the wind. If something were to come in slowly straight down then air friction would not be an issue. But gravity would.
FlightCommanderSolitude
SOC-13
<BLOCKQUOTE>quote:</font><HR>It's not just the streamlining, but the structural bracing, the landing gear, etc, that USL's just don't have. Plus the retraction and stowage fixtures for anything that would catch winds, like antenae, arms, etc. And remember, hulls are designed to keep pressure in, not out, unless at least PSL.<HR></BLOCKQUOTE>
I agree with aramis - starship streamlining doesn't just mean "wings and fins" but subsumes a broad mix of engineering enhancements and prerequisites that allow a starship to sustain the rigours of entering planetary gravity and atmosphere at reasonably exciting speeds.
As an example, I'm sure that the International Space Station would, if it was deeper in planetary gravity, snap apart at the hinges under its own weight.
As for air/rafts, they're going so slow and are so small (relative to starships) that they can be considered streamlined for purposes of atmospheric re/entry. Of course, there are much better ways to land on the surface of a planet, which is why I always considered the "air/rafts can reach orbit" rule as an emergency-only procedure. I mean, how comfortable could ten hours floating in an air/raft be?
-FCS
I agree with aramis - starship streamlining doesn't just mean "wings and fins" but subsumes a broad mix of engineering enhancements and prerequisites that allow a starship to sustain the rigours of entering planetary gravity and atmosphere at reasonably exciting speeds.
As an example, I'm sure that the International Space Station would, if it was deeper in planetary gravity, snap apart at the hinges under its own weight.
As for air/rafts, they're going so slow and are so small (relative to starships) that they can be considered streamlined for purposes of atmospheric re/entry. Of course, there are much better ways to land on the surface of a planet, which is why I always considered the "air/rafts can reach orbit" rule as an emergency-only procedure. I mean, how comfortable could ten hours floating in an air/raft be?
-FCS
<BLOCKQUOTE>quote:</font><HR>Originally filipled by aramis:
It's not just the streamlining, but....<HR></BLOCKQUOTE>
I really like the starship with this and that hanging off its hull. What great fun when the pirate craft pins it against an atmosphere. Stuff ripping off. Sensors go blind. The hull starts buckling. Now suddenly the captain thinks "perhaps it is worth the risk to jump rather than face certain destruction below or above."
What fun.
Gleeful sound of evil laughter.
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mark ayers, philosopher serf, editor of n2s; the journal for an empty mind
<http://www.users.qwest.net/~n2s/>
[This message has been edited by n2s (edited 23 June 2001).]
It's not just the streamlining, but....<HR></BLOCKQUOTE>
I really like the starship with this and that hanging off its hull. What great fun when the pirate craft pins it against an atmosphere. Stuff ripping off. Sensors go blind. The hull starts buckling. Now suddenly the captain thinks "perhaps it is worth the risk to jump rather than face certain destruction below or above."
What fun.
Gleeful sound of evil laughter.
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mark ayers, philosopher serf, editor of n2s; the journal for an empty mind
<http://www.users.qwest.net/~n2s/>
[This message has been edited by n2s (edited 23 June 2001).]
I've always considered streamlining to be structural as well as aerodynamic. I think that streamlining also consists of simply being able to survive in the gravity well of a planet.
For example, with grav thrusters or whatnot or not, the current Intl. Spacestation would be essentially a heap of rubble if it landed on any planet, as it's designed to be a free floating structure. If you want to add grav compensation, then it may be fine until the power is cut, THEN you get a nice heap of rubble.
For example, with grav thrusters or whatnot or not, the current Intl. Spacestation would be essentially a heap of rubble if it landed on any planet, as it's designed to be a free floating structure. If you want to add grav compensation, then it may be fine until the power is cut, THEN you get a nice heap of rubble.
Shadow Bear
SOC-12
<BLOCKQUOTE>quote:</font><HR>Originally posted by FlightCommanderSolitude:
As for air/rafts, they're going so slow and are so small (relative to starships) that they can be considered streamlined for purposes of atmospheric re/entry. Of course, there are much better ways to land on the surface of a planet, which is why I always considered the "air/rafts can reach orbit" rule as an emergency-only procedure. I mean, how comfortable could ten hours floating in an air/raft be?
-FCS<HR></BLOCKQUOTE>
Ten hours if nothing goes wrong and your suit air holds out. Then we don't want to run into any rain on the way up as it will freeze and they will have to break you free when you finally get there.
Sounds like a very chancy way to get up there.
As for air/rafts, they're going so slow and are so small (relative to starships) that they can be considered streamlined for purposes of atmospheric re/entry. Of course, there are much better ways to land on the surface of a planet, which is why I always considered the "air/rafts can reach orbit" rule as an emergency-only procedure. I mean, how comfortable could ten hours floating in an air/raft be?
-FCS<HR></BLOCKQUOTE>
Ten hours if nothing goes wrong and your suit air holds out. Then we don't want to run into any rain on the way up as it will freeze and they will have to break you free when you finally get there.
Sounds like a very chancy way to get up there.
Streamlining costs including bracing for gravity etc. seems like a good idea.
Unfortunately the rules don't reflect this. CT says that a USL ship can't enter the atmosphere of a world with an atmosphere digit of 2 or higher. So it can enter a digit 1 atmosphere.
The smallest atmos-2 world is a size 1 world
The largest atmos-1 world is a size 6 world
So an unstreamlined ship can land on the size 6 but not the size 1?
According to CT streamlining is for atmospheric reasons not gravity. But it does make sense if some of the cost involved was engineering to allow for the effect of gravity. Perhaps there should be a restriction on world size as well atmosphere for USL ships.
J.
Unfortunately the rules don't reflect this. CT says that a USL ship can't enter the atmosphere of a world with an atmosphere digit of 2 or higher. So it can enter a digit 1 atmosphere.
The smallest atmos-2 world is a size 1 world
The largest atmos-1 world is a size 6 world
So an unstreamlined ship can land on the size 6 but not the size 1?
According to CT streamlining is for atmospheric reasons not gravity. But it does make sense if some of the cost involved was engineering to allow for the effect of gravity. Perhaps there should be a restriction on world size as well atmosphere for USL ships.
J.
Book 5 (High Guard) p17
"Any ship of configuration 1 to 6 can land on a world with an atmosphere 0 or 1; for all other worlds, streamlining is required. Dispersed structures and planetoids cannot land on any world"
Ok, so cylinder, close structure, sphere and prolate sphere hulls all have legs. I think this makes a slow landing possible, although dangerous. I still think you need more drive than the local gravity well, 1G for moons, 2G for terrestial plants.
[This message has been edited by Uncle Bob (edited 30 July 2001).]
"Any ship of configuration 1 to 6 can land on a world with an atmosphere 0 or 1; for all other worlds, streamlining is required. Dispersed structures and planetoids cannot land on any world"
Ok, so cylinder, close structure, sphere and prolate sphere hulls all have legs. I think this makes a slow landing possible, although dangerous. I still think you need more drive than the local gravity well, 1G for moons, 2G for terrestial plants.
[This message has been edited by Uncle Bob (edited 30 July 2001).]
Spinward Scout
SOC-14 5K
"Eddie's... in the atmosphere"
Now what's he doing up there? Just hanging around?
Scout : ^ )
Now what's he doing up there? Just hanging around?
Scout : ^ )
Shadow Bear
SOC-12
While we are talking about landing on a world the landing site should be taken in to consideration.
Prepared landing areas would have to include ship size limitations (imagine landing something the size of the Queen Mary on a modern runway with just a few landing legs). Water landings may not be so much of a problem as long as the depth is enough to float the vessel (else it might get stuck in the mud on the bottom).
Landing on unprepared soil may also result in a vessel sinking its landing legs into the ground (x hundred tons on a surface of a few meters of landing legs).
Note in all the examples above I am assuming a gentle touch down. If the vessel came in like todays aircraft land the impact with the ground would increase.
Now add to this any heat build up from a non-streamlined re-entry and we have a very hot very large chunk of mass setting down on the planet's surface. Also when metal gets hot it tends to bend much easier and at some point it will not support its own weight. This could cause metal failure, gasket leaks, hull breeches, equipment misalingment and spinal mount failure.
Prepared landing areas would have to include ship size limitations (imagine landing something the size of the Queen Mary on a modern runway with just a few landing legs). Water landings may not be so much of a problem as long as the depth is enough to float the vessel (else it might get stuck in the mud on the bottom).
Landing on unprepared soil may also result in a vessel sinking its landing legs into the ground (x hundred tons on a surface of a few meters of landing legs).
Note in all the examples above I am assuming a gentle touch down. If the vessel came in like todays aircraft land the impact with the ground would increase.
Now add to this any heat build up from a non-streamlined re-entry and we have a very hot very large chunk of mass setting down on the planet's surface. Also when metal gets hot it tends to bend much easier and at some point it will not support its own weight. This could cause metal failure, gasket leaks, hull breeches, equipment misalingment and spinal mount failure.
GypsyComet
SOC-14 1K
So you just hope it's the *bottom* 7%...
[This message has been edited by GypsyComet (edited 15 August 2001).]
[This message has been edited by GypsyComet (edited 15 August 2001).]
