Solar Sail???????
 

The idea of a solar sail giving you extra speed is idiotic!!!
If a ship running on it's own engines deployed such a device, it would act as a drag chute,slowing down the ship not speeding it up!!! This needs to be removed from the game. Besides wouldn't you only move in the direction of the wind?

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Emperor Zodd:
The idea of a solar sail giving you extra speed is idiotic!!!
If a ship running on it's own engines deployed such a device, it would act as a drag chute,slowing down the ship not speeding it up!!! This needs to be removed from the game. Besides wouldn't you only move in the direction of the wind?<HR></BLOCKQUOTE>

The rationale for the component's ability is stupid, yes. And it should not work in systems without a sun -- but it does! All you need to do is change the description to something that makes more sense and find a better graphic. One of our "serious" modders who has some graphical skills could do that, I think.

In my own tech set I edited its size, making it 30kt, and added a 20 percent "to hit" penalty because it's so large & bulky that it must slow the ship down. This makes it useful mainly for NON-combat ships like transports. It ought to cancel cloaking, too, but there's no way to do what in the current game abilities. I'd invent a different technical description for it, but I can't make a decent graphic so I'll wait for someone else to do it. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif


[This message has been edited by Baron Munchausen (edited 07 January 2001).]

Re: Solar Sail???????
 

Well, Solar Sails could be made into a new tech tree, starting before ion engines.

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Emperor Zodd:
The idea of a solar sail giving you extra speed is idiotic!!!
If a ship running on it's own engines deployed such a device, it would act as a drag chute,slowing down the ship not speeding it up!!! This needs to be removed from the game. Besides wouldn't you only move in the direction of the wind?<HR></BLOCKQUOTE>


Well there is no wind in space nor is there anything to create any "drag" so a solar sail would most certainly not slow you down any. Whether it would speed the ship up or not depends on how fast it can go already. A solar sail over time could get you very close to the speed of light at least theoretically.

Re: Solar Sail???????
 

Drag in Space..hehe...sounds like a cheap sci-fi movie. As for the aerodynamic qualities of a "Solar Sail" in space...well..there is none. Drag is not an issue in a vacuum. The item could be as big and bulky as the empire state building and it wouldnt matter. As far as the collection of solar energy, again, a sun in a local system is not needed. The energy is collected from the billions of stars that permeate space. Now it is possible that a nebula or black hole may cause some interference, theres not enough data to support any theory here, just speculation. As far as ship maneuverability, this would depend on the proximity of large gravity wells and the design of the ship and the solar sails. But it would have to be a pretty large gravity field to reduce maneuverability significantly. The biggest problem a ship with any large set of solar panels (as we think of them today, would be with damage caused by micro-meteorites. But if someone in the future is gonna "invent" shields, warp drive, and a host of other sci-fi stuff, well, why not, some type of super efficient extra small hi-speed "solar sails". It's no more unrealistic than the rest of the items in the game. But its a game I do enjoy. Oops...gotto go, my flight to Alpha Centauri leaves in a few minutes..hehe http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Solar Sail???????
 

Actually a solar sail uses the solar 'wind' to drive the ship. Course it has to be BIG to make any difference.

And it could be used for braking when entering a solar system.

But for game purposes, I like to think of it as that big-ballon type thing (can't think of the name) racing yatchs use on the downwind leg of the race course...

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TerryM

Re: Solar Sail???????
 

Yes, a 'Solar Sail' in fact uses the solar wind as much as the pressure of light. Close to a star, the solar wind is much stronger. Farther out, the light would contribute more of the push. The thing is, it is VERY slow to build up speed and as everyone else has pointed out it can only work moving AWAY from the star. If there's one thing all races must have developed by the time this game occurs, it's space ship engines that let you go more or less directly from one place to another. Having to loop around a solar system a dozen times like the Cassini probe has been doing would be incredibly annoying. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

There is a new type of 'Solar Sail' in the works, btw. It's totally dependent on solar wind since it's magnetic rather than a big sheet of pLastic or something like that. It turns out you can just create a big magnetic field around your ship and pump out some plasma into it. The magnetic "drag" of the solar wind hitting this works just as well as the physical "sail" type of propulsion but you don't have to worry whether it will get all tangled up when you try to deploy after launch and it won't get torn by micro-meteors. Otherwise it's still a solar sail and only works in one direction. Great for primitives like us to send probes into the distant reaches of the solar system. Not worth anything to anyone who has high-velocity propulsion systems already and doesn't have to loop-the-loop around the solar system to get anywhere. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Solar Sail???????
 

Well, lets remember we are also using planet destroying weapons, things that 'collapse' black holes, and quantum reactors that can create infinite energy.
A solar sail definitely needs a star nearby to work. I also know that using Newtonian principles, you can definitely get the sail to work in at least a 180 degree arc of movement. Using a magnetic sail would result in the ability to move in a full 360 degrees (ie: both away and towards the star).
Now, as has already been mentioned, there is no such thing as drag in a vacuum. This is true, but much of space is not a total vacuum. A nebula, obviously, is a large area comprised of stellar gasses, and most certainly would create drag. A solar wind also creates a 'drag' force on an object in space, though it requires a very large ship and/or long distances to affect it noticeably. It also depends on direction of motion as to whether it is actually a drag force or a propelling force (the original principle of a solar sail).
So my point is that the solar sail is actually less ridiculous than a quantum reactor or 'collapsing' a black hole, so it should stay in the game. However, it should definitely not be allowed to work in nebula and black hole sectors.

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by apache:
the solar sail is actually less ridiculous than a quantum reactor or 'collapsing' a black hole, so it should stay in the game. However, it should definitely not be allowed to work in nebula and black hole sectors.<HR></BLOCKQUOTE>

but working on magnetic pricipals as you say, or working on other field / wave related principals it could function without a star. granted, it might have a hard time in deep space, but if nebulae are cool enough to disable shields or sensors then they certainly have enough background radiation puttering about to power a sail. we have definitly observed black holes cranking out all kinds of radio / microwave / high frequency wave output, so they should not have any problem powering a sail either.

as someone else pointed out, the simple answer is to look at it a little more abstractly, and maybe change the description from 'bounces photons at 90 degrees to generate force' to something more like 'manipulates naturally occuring fields and background radiation to indirectly propell a ship.'

Re: Solar Sail???????
 

I think the solar sail should only work when a ship runs out of fuel. And should be standard technology to all races. Then that would give ships a reason for still being able to move 1 space when they run out of fuel.

Re: Solar Sail???????
 

Actually, you can't get a 180 arc of motion with a solar sail. Sailing on earth only works because of the resistance the water provides against the hull. Without that force, all boats would always move in the direction of the wind. In the case of space, there isn't anything providing that restoring force, so the ability to use only a component of the force goes bye-bye.

Pity though... Solar sails just seem so frickin cool. Of course, if they are picking up distant stars, one could set them to pick up certain wavelengths and then coast in what ever direction you wished simply by finding a proper star and tuning the receptors to it. Hm...

I'll build an intergalactic spaceship, try it out, and get back to you.

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Marik Wahoooka:
I'll build an intergalactic spaceship, try it out, and get back to you.<HR></BLOCKQUOTE>

And was the Last ever heard from Marik Wahooka... http://www.shrapnelgames.com/ubb/ima...ons/icon12.gif

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Puke:
but working on magnetic pricipals as you say, or working on other field / wave related principals it could function without a star. granted, it might have a hard time in deep space, but if nebulae are cool enough to disable shields or sensors then they certainly have enough background radiation puttering about to power a sail. we have definitly observed black holes cranking out all kinds of radio / microwave / high frequency wave output, so they should not have any problem powering a sail either.

as someone else pointed out, the simple answer is to look at it a little more abstractly, and maybe change the description from 'bounces photons at 90 degrees to generate force' to something more like 'manipulates naturally occuring fields and background radiation to indirectly propell a ship.'<HR></BLOCKQUOTE>

I suppose you could call it "Electromagnetic Sail" then, and make a graphic image of some big magnetic coils to replace the sail thing. But then it doesn't belong in the stellar harnessing tech field. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Solar Sail???????
 

Actually, sailboats do not sail with the wind pushing the sail. They operate by the wind passing over the sail, like air passing over a wing. In otherwords, sails are nothing more than airfoils. Water resistance really has nothing to do with it. In fact, a sailboat makes the best speed when the wind is blowing perpendicular to the direction of travel. The only direction a sailboat can't travel is directly into the wind.
Anyways, I may be wrong about the actual arc of motion allowed by a passive sail, but the way it would move in other directions is by orienting the sail in an angle to the path of the solar wind. The wind particles hit, and bounce off of the sail, and so by Newton's 3rd law, generate an equal and opposite force. The way the sail is oriented determines the direction the desired reaction force will be in. And so you can move the ship in directions not along the path of the solar wind.

Re: Solar Sail???????
 

And don't forget about tacking! Zig-Zaging at angles allowing a sail to gain thrust, making the overall direction to be towards the sun...

BTW, I made solar sails a normal engine type.. with low speed (but some bonous movement, which means a lot since I use the "Engines Needed per Move" field in vehiclesize.txt), no supply usage, and made them appear at Stellar Manip 2... reducing Stellar Manip to 4 levels, and reducing cost from 10K to 5K... Gives a nice alternative for utility vessels.

[This message has been edited by Trachmyr (edited 08 January 2001).]

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by apache:
In fact, a sailboat makes the best speed when the wind is blowing perpendicular to the direction of travel. <HR></BLOCKQUOTE>

Perhaps my memory is faulty, but IIRC my sailboat always went fastest when I was sailing with the wind, i.e., with the wind directly astern. I suppose I might have had a poorly-designed sailboat. Worse, some landlubber said that the water resistance is irrelevant to tacking. LOL! What do you think the keel/centerboard is for?

But getting back to the original topic, I think solar sails should be just a picturesque name for a technology that really has little or nothing to do with sailing or 21st century human ideas about solar sails. So the description should be changed.

Re: Solar Sail???????
 

IMHO solar sails should be viewed as a device that uses stellar forces to give a ship extra movement. The exact form or way of working is not necessary. Should they work in a nebulae? yes, a black hole? yes. Why? because both contain solar/stellar energy in some motion/form, therefore it would be collectable by the device.
Why do we balk at some fictional ideas but not others? Human http://www.shrapnelgames.com/ubb/ima...ons/icon12.gif nature I guess.

Re: Solar Sail???????
 

For those who are interested [link]http://www.ugcs.caltech.edu/~diedrich/solarsails/[/link]. This is Caltech's Solar Sail website. It has TONS of great data. If you're patient, you can find some really interesting scraps hidden inside the news of NASA's JPL site.

My own take is that NASA won't use them for interstellar missions because they are the slowest known form of space propulsion, lagging far behind even ion drives. Even with massive ground-based lasers to augment the effectiveness, they can't hold up to any other form of propulsion and are not going to be used for anything except perhaps a few satelites as a means of giving them theoretically infinited maneuvering abilities so they can keep themselves in orbit much longer than ones with only chemical burners for maneuvers.

------------------
Compete in the Space Empires IV World Championship at www.twingalaxies.com.

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by apache:
Actually, sailboats do not sail with the wind pushing the sail. They operate by the wind passing over the sail, like air passing over a wing. In otherwords, sails are nothing more than airfoils. <HR></BLOCKQUOTE>

Aye, you're correct - when the ship is reaching or tacking. But straight downwind most sails (except the spinnaker - the big baloon-looking sail) are basically something for the wind to push against.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by apache:
Water resistance really has nothing to do with it.<HR></BLOCKQUOTE>

Water resistance is what keeps the ship moving in the direction it's pointed. Ships are shaped the way they are so that they move easily straight forward, but don't move laterally without a lot of effort. A flat raft with a sail will basically go straight downwind, no matter its heading. A rudder can help a bit, but you really need a keel or at least a centerboard to have any control.

The reason a sailboat leans over to the side is that the force from the wind over the sails is usually not in the direction the ship is heading - it's at an angle. Break the vector up into parallel and perpendicular components - the parallel component is what drives the ship forward, and the perpendicular component is what makes it tip to the side.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by apache:
In fact, a sailboat makes the best speed when the wind is blowing perpendicular to the direction of travel. The only direction a sailboat can't travel is directly into the wind.<HR></BLOCKQUOTE>

More or less. Some sailboats (like Hobie catamarans) actually do better on a close reach (sailing at an angle *into* the wind), while a spinnaker will give any ship a big boost downwind.

Re: Solar Sail???????
 

I haven't actually changed the descriptions or anything but in my own game (in my own mind, at least http://www.shrapnelgames.com/ubb/ima...ons/icon12.gif), the "solar sails" are actually catching otherwise wasted emissions from the engine output. If, say, a certain number of particles collide after being fired out the back, some of them are going to go rebounding back forward. Not many, granted, but a few. Those particles are what I picture being caught by the sails.

I also picture the sails as containing an electromagnetic field of some sort so that much of the "push" is actually EM repulsion from approaching particles with opposing charges.

A rationalization? Yep, you bet. Would it work? Eh . . . well . . . beats me. Ask somebody with more of a background in particle physics. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Psitticine:
I haven't actually changed the descriptions or anything but in my own game (in my own mind, at least http://www.shrapnelgames.com/ubb/ima...ons/icon12.gif), the "solar sails" are actually catching otherwise wasted emissions from the engine output. If, say, a certain number of particles collide after being fired out the back, some of them are going to go rebounding back forward. Not many, granted, but a few. Those particles are what I picture being caught by the sails.<HR></BLOCKQUOTE>


hopefully not. the sail (if working in traditional sail fasion) would be deployed in front of the ship to actually pull it. if it was deployed behind, it would need to be attached to rigid struts instead of long cables (or whatever) so that it would not wrap arround the ship when it 'inflates'

Re: Solar Sail???????
 

This is a facinating thread. Very deep for a game forum. Basically everybody has had a little piece of the truth.

A ship with a square sail and no keel or rudder (a raft) will go in the direction of the prevailing wind. If you turn the sail to try and move at an angle with the wind, the wind will simply rotate your ship so that the square sail is once again perperdicular to it.

A ship with a square sail and a keel or rudder can follow the wind or go at angles to the wind (but still with it) because the friction of the water against the keel or rudder will keep the ship from rotating.

A ship with a triangular sail can go into the wind at angles by aerodynamic principles similer to how a wing on an aircraft generates lift.

A solar sail can go with the "solar wind" or at angles to it by newtons principles of equal and opposite reaction. If you turn your sail at an anlge to the solar wind it will push your ship at an angle to the wind. It will also try to rotate your sail back to perpendicular, but by use of chemical rockets or some other thrust generating device you can keep the sail at the anlge you want. Similar to the keel or rudder on a water craft.

No principle I can think of would allow a solar sail to go into the solar wind. An interstellar solar sailing ship would use the force of a star to get enough velocity. Once up to velocity, it would use the destination star's wind to brake. If you wanted to travel through a system without stopping you would have to retract the sail while approaching the star. Once past it you could extend the sail again to use that star to continue you on your journey or change course.

[This message has been edited by geoschmo (edited 11 January 2001).]

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Puke:

hopefully not. the sail (if working in traditional sail fasion) would be deployed in front of the ship to actually pull it. if it was deployed behind, it would need to be attached to rigid struts instead of long cables (or whatever) so that it would not wrap arround the ship when it 'inflates'<HR></BLOCKQUOTE>

It wouldn't be working in traditional sail fashion. There's no wind in space, you see . . .

&lt;ducking behind nearest plantoid&gt; I couldn't resist! I couldn't resist! http://www.shrapnelgames.com/ubb/ima...ons/icon12.gif

What I had in mind was, in fact, a rigid structure built around the rear of the ship. Not nearly as large as a real solar sail either.

As I say, not staggeringly logical, but that's space opera for ya. http://www.shrapnelgames.com/ubb/images/icons/icon7.gif

Re: Solar Sail???????
 

But there is wind in space. Solar wind. It is a stream of ionized particles (typically hydrogen, maybe helium, electrons, and other subatomic particles) eminating from the sun, or any star for that matter.
This wind, as far as I know, leaves from stars in every direction, and the particles are moving at very, very high speeds. Shock waves start to form when this wind approaches planets. There is a massive shock wave between the earth and the sun, caused by these particles.
Solar wind is as much a form of wind as a breeze, a hurricane, or any other terrestrial air currents. You just would not want to stand in this wind. You would probably not survive very long.

Re: Solar Sail???????
 

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by geoschmo:
A ship with a square sail and a keel or rudder can follow the wind or go at angles to the wind (but still with it) because the friction of the water against the keel or rudder will keep the ship from rotating.

A ship with a triangular sail can go into the wind at angles by aerodynamic principles similer to how a wing on an aircraft generates lift.
<HR></BLOCKQUOTE>

Actualy ships with square sales can sail up wind like ships with wing shaped sails. the difference is that they just can't get quite as high up (i.e. closer to the wind). This is called pointing. Most modern keel boats can get to within 30 degrees of the wind when beating up wind (zig zaging up wind). The older square sailed boat usualy managed 45 degrees or 60 degrees (including the drift). The thing to remember is that even with a square sail, you could turn it around the mast and have one part of the sail near the bow and the other part near the stern. This allowed you to point the boat at less than 90 degrees to the wind and still catch the wind. The shape of the sail is inefficient for this but not ineffective.

Strangeone. (who was a sailing instructor at one point in his mis-spent youth).

Re: Solar Sail???????
 

We have a lot of sail boaters here. Not me, I'd rather skim across the surface at high speed in my bass boat!

Re: Solar Sail???????
 

Here's an idea: maybe the "solar sail" is capturing the solar wind (and other emanations, like background radiation in nebulae) and feeding that energy into the engines as a kind of "overdrive". That avoids the problem of it acting as a "sail". It would really be more of a ramscoop... hmmm... now I have more ideas... I'll have to go off and think now...

Re: Solar Sail???????
 

*Sigh* <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>For those who are interested http://www.ugcs.caltech.edu/~diedrich/solarsails . This is Caltech's Solar Sail website. It has TONS of great data.<HR></BLOCKQUOTE>

The site has some detailed explanations of what solar sails are, how they work, and how they can be used to let a vehicle approach the star.

#1 Solar sails do not harness the solar wind: <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Many people assume that because here on Earth they feel wind but not sunlight, that solar sails must be pushed by the solar wind. However, there is a very big difference between space and Earth. Earth is wrapped in a thick layer of gas that is felt as wind whenever it moves. In space, there is no air to move around and cause strong winds like we feel on Earth. The solar wind is an extremely tenuous flow of particles ejected by the sun which exerts very little force on anything it hits. The reason people worry about the solar wind is because many of the particles have an electric charge that can hurt people and electronics, or can push a magnetic sail. <HR></BLOCKQUOTE>

#2 They approach a star not by tacking, but by narrowing an orbit (a very slow process). <BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Solar sails are more complex. The force produced by sunlight on a solar sail is the addition of the forces from the incoming sunlight and the reflected sunlight. This force always points away from the sun, and is at an angle that is close to a right angle to the surface of the sail. If this force is angled back along the solar sail's path, the spacecraft's orbit will start to shrink, bringing it closer to the sun. If the force is angled foreward along the spacecraft's path, the orbit will grow and the solar sail will head farther from the sun.

This is the general idea behind "tacking into the sun" for solar sails. In real practice, the behavior of a solar sail is more complicated because sunlight pushes not only along the spacecraft's orbit, but also straight out from the sun. These effects are beyond the scope of this document, however.
<HR></BLOCKQUOTE>

You can find all kinds of neat ideas, including several different designs of potential solar sails, and some fun facilities to make use of them. For example, NASA was considering using a massive ground-based laser (5-million megawatt) on continual fire to propel a solar-sailed raft to Alpha Centauri, until the ion and plasma pulse rockets turned out to be both cheaper and faster.

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Compete in the Space Empires IV World Championship at www.twingalaxies.com.