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atgxtg
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 Posted: Tue Jun 22, 2010 4:31 pm Post subject: |
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| ZzaphodD wrote: | | What I mean with maneuverability is actually that the system favours the heavier (engine stacked) freighter. A 3D maneuverability freighter is not very hard or expensive if one uses the (limping) TF rules (you can even find on 'as is' i think). This means that the A-Wing has only a 1D advantage. With two pilots at 5D thats only 8D vs 9D. This does not really represent the difficulty of changing direction with a freighter full of stacked engines. |
I'll recheck, TF, but I though that in 2nd edition that maneuverbity was enhanced with the same rules they used in the rule book, limiting ships to a +1D+2 imprvement.
With my design system, upping the YT-1300 to move like a A-Wing is expensive and eats up half the cargo hold.
| ZzaphodD wrote: |
WEG moved away from Space speed die codes because the speed of the ship meant so little compared to the skill of the pilot. Strange they didnt do the same thing with maneuverability, which suffers from the same problem. |
Probably becuase it favors the PCs, and isn7t as disasterious to chases. They did come up with a better method in Star Warriors. In Star Warriors, pilots would pick maneruvers (bank, adjust throttle, roll, snap fire, etc.), and total up the difficulty of all the maneuvers they did during a turn to get the final difficulty they needed to roll against. More maneuveraqble ships had lower difficulties, which became more signficant as you did more maneuvers.
| ZzaphodD wrote: |
Regarding you table. It says that an A-Wing accelerates at 5100G if I read this correctly. So, if I understand your 1G example, means that one second of acceleration moves this ship about 50 km? |
You math is almost right. 5100Gs is an acceleration of 50,031m/second/second (you can go with 10m/G instead of 9.81, it is only a 2% error, and make the math a lot easier).
But that is accleration, not velocity. So if you go look up the equations of motion for constant accleration you get V=1/2at^2.
THat measn that in 1 second the A-Wing will acclerate from a dead stop to a speed of 25,015.5 meters per second, or about 90,000 kph.
But, that is just the first second. If the A-Wing acclerated for a full round (5 seconds), it would end up travelling 25 times as fast, or around 2 and a quarter million kph. If true, an A-wING could travel from Earth orbit to the Moon in just a few seconds. It gets enven stranger is you consider than in space there really is no max speed. As long as the fuel held out, an Star Wars ship could acclerate to incredible speeds, and zip across and round a solar system in minutes.
Not that I reccomend apply real world physics here. It is a case of garbage in, garbage out.
The reason why is that the accleration values are insanely high, a few orders of magntiude higher than I'd have preferred. I used them becuase they are the values that are used in the New Essential Guide to Vehicles and it is one of the few "real" values give for the ships. My speed formula is set up so that most of the ships match up with both the Guide and thier Space ratings. Vritually every ship is withing 1 point of it7s Space rating. |
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ZzaphodD
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| Posted: Tue Jun 22, 2010 4:56 pm Post subject: |
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Regarding the Maneuverability issue, the most simple solution would be adding perhaps 2D as a kind of 'scale bonus' to all starfighters.
One can still use the G values as a relative value for ships speed so that they can be compared to each other. |
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atgxtg
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| Posted: Tue Jun 22, 2010 5:53 pm Post subject: |
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| ZzaphodD wrote: | | Regarding the Maneuverability issue, the most simple solution would be adding perhaps 2D as a kind of 'scale bonus' to all starfighters. |
Is it an issue? Most Starfighters have a higher manevuerability than freighters anyway. About the only starfighter that I think needs more maneuverability is the TIE fighter, but I suspect that it was nerfed so that PCs farm kids in X-Wings would have an edge.
Just how cheap and easy is the high maneuverability AYT-1300 in Tramp Freighters? |
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ZzaphodD
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| Posted: Thu Jun 24, 2010 4:46 pm Post subject: |
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| atgxtg wrote: | | ZzaphodD wrote: | | Regarding the Maneuverability issue, the most simple solution would be adding perhaps 2D as a kind of 'scale bonus' to all starfighters. |
Is it an issue? Most Starfighters have a higher manevuerability than freighters anyway. About the only starfighter that I think needs more maneuverability is the TIE fighter, but I suspect that it was nerfed so that PCs farm kids in X-Wings would have an edge.
Just how cheap and easy is the high maneuverability AYT-1300 in Tramp Freighters? |
Looking through Starship Stats Starfighters with 3D or above in Maneuverability are in minority. In general they have 2D and a pip or two.
Space transports in general have between 1D and 2D, with most at 1D and perhaps a pip or two.
I dont think this is enough of a difference. One is a craft made espacially for dogfights and the other is made mainly for carrying cargo. Especially in the light of the 'cheap' engine stacking. With a larger difference in maneuverability the 'chea' engine power could only be used in clear space, as the freighter would have trouble maneuvering at great speeds. |
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atgxtg
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| Posted: Fri Jun 25, 2010 2:49 pm Post subject: |
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I don7t plan on invalidating all the preexisitng stats for freighters or starfighters! So I guess that 4-5pip difference is going to remain.
But, I will say that as far as my design system goes, it will be impratical to make a freighter move and maneuver like a fighter.
What happens is that a certain percentage of the total mass miust be dedicated to engines to get a certain speed or maneiuverability. Engine effciency changes this some, but at a big price. For example, if you stack enginjes to get a YT-1300 to be as fast ANS as maneuverable as a A-Wing, it will be very expeinisve, and have no cargo space to speak of. Basically, what you7d end up with would be a slighty tougher fighter that costs at least 3 times as much as a fighter,. At least.
Oh, back on to Maneuverability thing, I don7t thing the difference is too small. At least not if you go with the real world analogues. In the real wolrd, a Piper Cub, or even a cargo plane can usually out turna fighter jet. The fighter jet might be able tpull twice as many Gs, but maneuverabilty goes down with the sqaure of velictity, so since the fighter jets tends to be moving much faster, they are actually less maneuverable. |
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ZzaphodD
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| Posted: Mon Jun 28, 2010 6:13 pm Post subject: |
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| atgxtg wrote: | | Oh, back on to Maneuverability thing, I don7t thing the difference is too small. At least not if you go with the real world analogues. In the real wolrd, a Piper Cub, or even a cargo plane can usually out turna fighter jet. The fighter jet might be able tpull twice as many Gs, but maneuverabilty goes down with the sqaure of velictity, so since the fighter jets tends to be moving much faster, they are actually less maneuverable. |
Perhaps you should compare the cargo plane to a Mustang fighter instead. Or a cargo jet with a jet fighter. Also, when comparing to airplanes you have to take things like lift into the consideration. A high speed airplane is not designed to perform at its best at low speeds, lift and turning performance being hampered. In a fictional space situation thrust and the ability to direct that into maneuverability is all you have to think about. Here mass is the only thing working against you.
Also, the example is not really relevant. IRW one plane is moving at a couple of hundred miles per hour and the other can move at probably mach 2. In SW the 'Fighter' is probably only able to move about double the speed of the freighter. I dont think the freighter will be outturning the fighter at half the speed. |
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ZzaphodD
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| Posted: Mon Jun 28, 2010 6:27 pm Post subject: |
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| atgxtg wrote: | I don7t plan on invalidating all the preexisitng stats for freighters or starfighters! So I guess that 4-5pip difference is going to remain.
But, I will say that as far as my design system goes, it will be impratical to make a freighter move and maneuver like a fighter.
What happens is that a certain percentage of the total mass miust be dedicated to engines to get a certain speed or maneiuverability. Engine effciency changes this some, but at a big price. For example, if you stack enginjes to get a YT-1300 to be as fast ANS as maneuverable as a A-Wing, it will be very expeinisve, and have no cargo space to speak of. Basically, what you7d end up with would be a slighty tougher fighter that costs at least 3 times as much as a fighter,. At least.
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This was what I was looking for. |
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atgxtg
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| Posted: Wed Jun 30, 2010 12:54 pm Post subject: |
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| ZzaphodD wrote: | | [This was what I was looking for. |
Yea! Nice to know that.
Where things stand now, I'm fairly happy with how engines, speed and maneuverabilty are working out. Even if the fighters are a bit heavier than we would all have liked (and once everything is working I can try to go back and scale things down more. The problem is that if I make the starfighters mass similar to modern fighters, then the freighters end up requring massive engines to keep thier speed relationship. At least now, I can keep the mass ratio between fighter and cargo plane and get good results. The difficulty is that big spaceships is starwars are more like naval ships than aircraft, and would end up with the same speed relationship to fighters if I scale the fighters down too much. It is more a problem with freighters than with Captial Ships).
Most of the math is working out okay, and the engine costs seem to be making sense, too.
The current cost for an egines is the power output (in kilotons) sqaured, times 10 Credits (per ton).
The default engine uses 1 EU per 10 kilotons of thrust, but a design can be make more or less effecicent aat a portortial increase in cost (so an egnine that uses 1EU per 20kt would cost twice as much).
Right now< I7m working on reversen eigneering the Engines of various ships in Starwars so I can put together an ion drive table. I just have to see how many ships give the models numbers for thier engines. |
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ZzaphodD
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| Posted: Wed Jun 30, 2010 4:39 pm Post subject: |
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About the mass problem with fighters.
Fighters probably have lighter cutting edge engines than freighters. Looking at the cost of fighters this support that idea somewhat (even if the cost is not that much higher). Also, with little weight, they dont need that much thrust compared to a freighter (if we dodge the bullet that is the fact that theres probably other factors to a high end engine but raw thrust). |
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atgxtg
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| Posted: Sat Jul 03, 2010 12:12 pm Post subject: |
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| ZzaphodD wrote: | About the mass problem with fighters.
Fighters probably have lighter cutting edge engines than freighters. Looking at the cost of fighters this support that idea somewhat (even if the cost is not that much higher). Also, with little weight, they dont need that much thrust compared to a freighter (if we dodge the bullet that is the fact that theres probably other factors to a high end engine but raw thrust). |
You've put your finger right on the problem.
With the construction system SPACE speed is a function of the thrust-to-mass ratio. This is the same as the G rating. That is, a ship that can pull 3000Gs has around a 3000:1 Thrust-to-Mass Ratio.
Now, any chance in mass must have a proportionate change in thrust to keep the same ratio. So if you double the mass of a ship you will need to double the thrust to keep the same performance.
Now here is the problem. If a fighter, such as an A-Wing has, say, 1/10th the mass of a YT-1300 then it only needs 1/10th the thrust to get the same G rating and SPACE speed. This would mean portionally smaller engines. Now, since the A-Wing has a SPACE rating 3 times that of a YT-1300 it does need bigger engines to get SPACE 12, but not much bigger. Now based on the size of the engines and the fact they are supposed to be cutting edge designs, we would end up withA-Wings zipping around at Space3 25 or some such.
That is why I preferred to keep the thrust to mass ratios between fighters and freighter similar to those between jet fighters and jet cargo planes. |
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Falcon79
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| Posted: Wed Jul 07, 2010 6:03 pm Post subject: |
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all this math makes my head hurt.... I have Dyscalclia you know. 
_________________
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atgxtg
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| Posted: Fri Jul 09, 2010 3:18 pm Post subject: |
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| Falcon79 wrote: | | all this math makes my head hurt.... I have Dyscalclia you know. |
Don't fret. Most of the math is my headache, since I'm working up the design rules, and want to see how things work. Most of it is going to be for my benefit for desgining engiines, weapons and other systems.
THe end user won't need to know or do most of this. People who want to can go into a lot of detail, design custome engines, laser cannons, and even adjust the ship's thrust-to-mass ratio when threy add an automatgic coffee maker, but they won't have to. Most ships will simply be built by picking components like ion drives or laser cannons off a table.
You won't need an egineering degree to use this.
For the most part the the math consists of simple addtion and subtraction. filling up the tonnage and working up the cost of the vehicle. The most complicated bit is to divide the engine thrust by the ship's mass to get a G rating, and looking that up on a table to get a SPACE score. Even that is there just to make sure that massive ships require massive engines. |
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ZzaphodD
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| Posted: Sat Jul 10, 2010 10:42 am Post subject: |
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| atgxtg wrote: | | Falcon79 wrote: | | all this math makes my head hurt.... I have Dyscalclia you know. |
Don't fret. Most of the math is my headache, since I'm working up the design rules, and want to see how things work. Most of it is going to be for my benefit for desgining engiines, weapons and other systems.
THe end user won't need to know or do most of this. People who want to can go into a lot of detail, design custome engines, laser cannons, and even adjust the ship's thrust-to-mass ratio when threy add an automatgic coffee maker, but they won't have to. Most ships will simply be built by picking components like ion drives or laser cannons off a table.
You won't need an egineering degree to use this.
For the most part the the math consists of simple addtion and subtraction. filling up the tonnage and working up the cost of the vehicle. The most complicated bit is to divide the engine thrust by the ship's mass to get a G rating, and looking that up on a table to get a SPACE score. Even that is there just to make sure that massive ships require massive engines. |
If you put it into an excel sheet or something similar you just have to punch in the numbers and see what comes out on the other end.
I have myself tried to come up with a formula for thrust vs mass. The problem I have is that when I come up with a good formula for determining freighter Space speed (in accordance to GG6) the lighter ships (ie 100 ton couriers) come out at Space 16 or so. Given the fact that the Space 12 A-wing seems pretty close to cutting edge speed, that seems a bit daft. |
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atgxtg
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| Posted: Tue Jul 13, 2010 2:31 pm Post subject: |
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| ZzaphodD wrote: |
If you put it into an excel sheet or something similar you just have to punch in the numbers and see what comes out on the other end. |
THat is what I have been doing to test the rules. I can just plug numbers into the speadsheet and see if whart comes out, and then see if that works out alright.
| ZzaphodD wrote: |
I have myself tried to come up with a formula for thrust vs mass. The problem I have is that when I come up with a good formula for determining freighter Space speed (in accordance to GG6) the lighter ships (ie 100 ton couriers) come out at Space 16 or so. Given the fact that the Space 12 A-wing seems pretty close to cutting edge speed, that seems a bit daft. |
Yeah, that is what I7ve been tryinto to explain about the movement rates, and why the 24mt A-Wings don't work out.
You see, with aircraft, cargo planes typically weight only about 3 times as much as a fighter. But, if you make A-Wings and other fighters in Star Wars weight in at around 30 tons then freighters end up weighting about ten times as much as a SW fighter and throwing the thrust to mass ratios off. The end effect is that the fighters start zipping around.
That is one reason why I kept with heavier fighters. THey keep the TMRs (thrust-to mass ratios) down so that the realtive speeds match up. |
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