ADF/MR question

BlueKomet's picture
BlueKomet
January 26, 2011 - 2:36pm
I'm sure this has been answered before but I couldn't find it while looking at the forum. One thing that always seemed odd was the question of acceleration and manuevering. At the low speeds we played back when the game was new it didn't seem to matter much. You were moving at the astronomical speed of NINE hexes per turn and went through a 180 degree turn and were now moving at a speed of nine hexes per turn the other way. I loved it!

However....

That would be effectivly an 18G move and my ADF was only 3. This was before David Webers inerital compensators and the crew who had NO artifical gravity would be unconscious and suffering severe brain damage. Compound that with ships moving up to 200 hexes per turn able to turn 180 degrees and reality is not only suspended it is essentially drinking a double espresso every minute and having paranoid thoughts!

Moving at 3Gs would be a burden on a crew anyway but sudden turns would paste them on the walls.

Has anyone addressed these problems while still preserving what was my favourite sci-fi game of all time?
Comments:

Sargonarhes's picture
Sargonarhes
January 26, 2011 - 4:02pm
The high G manuvers and acceleration are only done at combat speeds, which your ship is not going to be moving like that all the time. So most times a ship will be thrusting at only 1G. What I proposed is most ships even in combat stayed at 1G of thrust and only went into higher Gs for evasive manuvers when the missiles and torpedos came zeroing in, this should reduce the stress on the crews.
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Deryn_Rys's picture
Deryn_Rys
January 26, 2011 - 4:09pm
Perhaps it has to do with the Hex being 10,000km accross and what we might actually be seeing is a ship making small incremental changes during the ten minutes that a turn actually means. Where we see the ship move only ten hexes and make that 180 degree turn on the board, the truth is that ship has crossed 100,000 kilometers in ten minutes most of the time coasting on built up inertia, and only using short burns of its primary engines and it's maneuvering thrusters to turn to a new facing.

At least that's how I make sense of it, though I could be wrong.
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Ascent's picture
Ascent
January 26, 2011 - 4:54pm
I'm with you, BlueKomet. I am in the process of working out a limiting mechanic that involves both ADF and MR. MR is the real kicker. Maneuvering by just 1 hex side, even at just 1 ADF (2.8gn) acceleration produces some major g-forces.

Revised: 17 gees is apparently sustained for several minutes. Which direction a person faces in these maneuvers is apparently a factor.

I'm in middle of researching all of this.
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Ascent's picture
Ascent
January 26, 2011 - 4:36pm
Deryn_Rys wrote:
Perhaps it has to do with the Hex being 10,000km accross and what we might actually be seeing is a ship making small incremental changes during the ten minutes that a turn actually means. Where we see the ship move only ten hexes and make that 180 degree turn on the board, the truth is that ship has crossed 100,000 kilometers in ten minutes most of the time coasting on built up inertia, and only using short burns of its primary engines and it's maneuvering thrusters to turn to a new facing.

At least that's how I make sense of it, though I could be wrong.

The key words there is "10 minutes". 10,000km in 10 minutes is 1000 in 1 minute or 16.7km/s. The forces produced by even the slightest maneuver at that speed would be intense. First you must remember that the ship has to turn at a right angle to the maneuver to make it happen. That in itself produces some significant gees on the extremities of the ship (Think of a massive tilt-a-whirl ride, except this one's moving a thousand times faster around the arch and the distance rotated is up to 100 times larger), and then the ship now moves in an arch similiar to a massive space station. Remember, the larger the space station, the slower it needs to rotate at its center to simulate 1 gee. This space station is the equivallent in diameter to a planet the size of Neptune or larger, assuming 1 ADF/MR for turning around in a 1 hex per turn rotation. In thirty minutes you have made the turn around, except in this senario, you don't have a gravity well to offset the gravity with a slingshot effect, which means you're feeling every bit of it for 30 minutes. Now, if you're traveling at 3 hexes per turn, that would mean you make this massive turn in just 10 minutes.

Now I still have yet to calculate it, but that sounds to me like an awful lot of strain.
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Shadow Shack's picture
Shadow Shack
January 26, 2011 - 4:54pm
Just remember, when you're moving at 9 hexes/turn (or any other starting velocity for that matter) there is no gravity until you accelerate/decelerate or maneuver. The only time you feel the gravity during that ten minute turn is during such maneuvers, so accelerating by an ADF of 3 means you can either do it all at once or in increments over that ten minute period...you're not neccesarily feeling the gravity during that entire time. 

By the rules, that three-hex 180º turn can be performed at 3 1/3 minute intervals. Even accelerating by 5 (fighters and assault scouts) means you can accelerate at two minute intervals, so it's not like the occupants are experiencing a zero-G to 15g increase in a few seconds...like Ascent said the ten minute turn is the key (still, 15G is quite a pull at the end of said maneuver).

Of course anytime a ship is expected to make maneuvers, the crew and passengers should be secured...with a 300K km range on a standard rader you have plenty of time to do that. By the time the ship is ready for maneuvers, any loose crewmembers/passengers turn into self-lethal pinballs.
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Deryn_Rys's picture
Deryn_Rys
January 26, 2011 - 5:04pm
(I don't think the people at TSR were to concerned with real world physics when they dreamed this stuff up.) Doesn't the rules state that before a battle most ships order everyone into space suits and to be strapped down while completely depressurize their ships. Perhaps the vacuum suits they use in these cases aren't like the ones used in normal operations and are designed to absorb tremendous amounts of G-force pressure. As for the stress on the ship itself maybe the federanium (ummm...fuzzy science alert) that they build the ship's superstructure with is so strong that it can easilly survive the stress of making those outrageous maneuvers. 
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Ascent's picture
Ascent
January 26, 2011 - 5:16pm
There are anti-g-suits, but these only protect the wearer so much.

Even if just a game, it's not a fantasy game. It's an adventure game. It should still follow rules of physics. Personally, I get disinterested in video games with no concern for physics. Even if all the characters jump around like their on the moon, I still expect some attention to physics.
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BlueKomet's picture
BlueKomet
January 26, 2011 - 5:17pm
Just off the top of my head, to make a course change of 60 degrees (one hexside) at a speed of 10 hexes per 10 minute turn would require a 15G side vector within one turn (or more realistically 5 turns of 3G acceleration at 90 degrees to initial heading. you would still be travelling at 10 hexes per turn. you would also travel an additional 50 hexes to make this turn. Now if we had artifical gravity or inertial compensators we could accelerate much faster but turns would still be exaggerated. What is needed is a reactionless drive field like gravitic impellers that wraps the ship and crew in an force bubble. But then you are no longer on the frontier. You are playing Star Trek.

Maybe a system that restricts how much you can turn based upon your rate of movement. Say at 5 hexes per turn you can make up to 4 heading changes, and then lose 1 heading change every 5 hexes per turn. Thus moving 20 hexes per turn you can alter your course by 1 but at 21 you can no longer turn without slowing. Even then your engines would be working damn hard changing your base vector. It would also make ships slow down for combat.

As it is everyone would be locked in their ships chairs for hard manuevering. You want to keep that low tech (non star trek) feel to the game

Ascent's picture
Ascent
January 26, 2011 - 5:46pm
Can you share your calculations, BlueKomet? It might help me to make faster work of my research (Trying to understand physical math is daunting for me). At least what you can recall about how it's done.
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BlueKomet's picture
BlueKomet
January 26, 2011 - 5:54pm
My figure are not perfect. If you are moving 10HpT in one direction then I figure you need to generate a side vector of about 15 HpT to change course AND keep your speed. Slowing down would be faster and easier but a pursuer could catch up

Ascent's picture
Ascent
January 26, 2011 - 6:08pm
What I mean are the g-forces involved in maneuvering. I know I have a lot of math to do. So a head start in understanding what I'm doing would be much appreciated.
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BlueKomet's picture
BlueKomet
January 26, 2011 - 6:30pm
Okay my math was off but I learned the new math so that should be no surprise.
I went to a website that calculates vectors
10G at 180 degrees (current speed)
10G at 60 degrees (acceleration)
=
10G at 120 degrees

The same can be acheived with 3 turns of 3G accel followed by 1G accel for 1turn

My original idea of 15G at 90 degrees would put you on a course of 123.69 at a speed of 18Gs

Website for my calculations http://www.1728.com/vectors.htm

This is real world, I think in a game (a 2D one at that) we can take a few liberties. Mind you the image of a ship coming out of jump space at 200 HpT and making a 18 degree turn and heading back into jump space is just bewildering my mind.

Shadow Shack's picture
Shadow Shack
January 26, 2011 - 7:03pm
The way my simple mind wraps around maneuvering (facing changes) is the RCS thrusters reposition the ship to a new facing, and then the main drives fire to push the craft in that direction. Hence, you only feel "gravity" from the floor, no sideways forces.

So to make that 180º turn you could feasibly make a 90º facing change, fire the thrusters, and as the ship moves on that new perpendicular vector --- at which point you repeat it again. In the case of canon, it takes a minimum of three hexes to execute this maneuver, but instead of 90º changes you do it in 60º increments.


Now the game designers did all this with a board game in mind, not realism. If realism is what you're after, you need to have a plain map with no defining units (squares or hexes or octagons or whatever) and draw lines while utilizing vector movement, something akin to Traveller or Art's KH Vector rules (the latter which are penned for a hex map).
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BlueKomet's picture
BlueKomet
January 26, 2011 - 7:16pm
I agree with you, my only problem is that it starts to look a bit ridiculous when a ship changes that much speed in that short a space. Last thing I want is to need a calculator or Ipod App to find out if I can turn a corner. I think you need to move a bit more when making the turn. For instance moving say 3 hexes between facing changes. The actual  (real) forces involved would crush the crew to paste but consider this as an idea. You are driving a car at 10 miles an hour. Your turning circle is quite small. At 60 miles an hour you need more room to turn the same angle.

I'm not suggest going realistic, but I thing our ship moving 10 HpT (a frigate perhaps UPFS Speedy) changes facing at the start of his turn, moves 3 hexes, changes facing again and moves another 3 hexes, and changes facing a third time an moves his remaining 4 hexes 180 degrees from his original course. The Sathar Destroyer pursuing him only has an MR of 2 and thus cannot make the same turn. The turn might carry him within the range of the destroyers guns but the frigate will be able to pile on more speed

Shadow Shack's picture
Shadow Shack
January 26, 2011 - 7:26pm
MR limits based on current speed is something I could live with, the faster you go the fewer maneuvers you can execute. It makes sense. It would also have to be something formulaic, I too do not want a scientific calculator introduced to my games.

In that regard, there would utlimately be a maximum velocity for maneuvers if you went with a formula, anything faster means you're heading toward jump velocity and can only make minute course adjustments as such.


BTW - a frigate and destroyer both have the same MR (3), it's their ADF scores that differ (4 on the frigate, 3 on the destroyer).
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BlueKomet's picture
BlueKomet
January 26, 2011 - 7:35pm
Sorry I took that MR from the basic rules. I agree with your reasoning. The faster you go the harder it is to turn.

Malcadon's picture
Malcadon
January 26, 2011 - 8:43pm
The ADF system makes sense, but the MR part makes no sense whatsoever. In my games, I just call ADF "Thrust", and allow it to be used to make turns, but with "Maneuvering", I make it a 0-average score that can be adjusted by increments of 5 (usually -10 to +10). Maneuvering adjusts piloting rolls, and fixed-forward weapons (cannons, assault rockets, and equivalent).

The only time I can justify the normal MR rule, is with the sort of artificial gravity system found in Firefly, that would allow for some rather ponderous turns do to the weird physics in play.

jedion357's picture
jedion357
January 26, 2011 - 9:05pm
BlueKomet wrote:
Now if we had .... inertial compensators ....


Ahhh but we do have inertia compensators in the Star Frontiers game. The inertia screen while not based on RW tech would have to be based on the same tech as an inertia compensator.

There is always the arguement of paying attention to physics but it is a game so the way I see it we can
hand wave the tech and say that the inertia defense screen was developed after someone figured out how to keep star ship crews from turning to paste at High G manuevers with the development of an inertia field for ship. (if a ship takes a hit in its inertia field generator then its crew feels all the Gs for combat manuevers- penalties for doing stuff no doing damage control as the engineer would now have to strap in, penalties for firing weapons or player has to fall back on computer altogether to fire weapons.

or we can adapt the Shades of Montion article (I think that is what it was called) which dropped MR and you used just your ADF to turn the ship. its more complicated but seems playable. (though I suspect the G forces involved in that style of play will still require the Inertia field compensator for crew comfort and survivability).

Bottom line is the KISS rule Keep it Simple adding a complicated strap on rule that means form figuring or consulting will slow play and fun IMO.

EDIT: Oh yeah say what you will but any game with aliens in it is Fantasy.
I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers!

SFAndroid's picture
SFAndroid
January 27, 2011 - 5:38am
jedion357 wrote:
BlueKomet wrote:
Now if we had .... inertial compensators ....


EDIT: Oh yeah say what you will but any game with aliens in it is Fantasy.


Bingo.

Babylon 5 Earth Force Roosevelt-Class destroyers have the crew strap in (no suits) and perform pretty heavy turns, and are pretty much Star Frontiers level of technology. Here's a link:

http://www.kitsune.addr.com/SF-Conversions/Rifts-B5-Ships/Earth_Roosevelt.htm

I agree...alot...with the physics thing, but, something has to give in a gaming environment.  Trying to apply today's standards to a far flung future would be like trying to explain flight to neanderthals.

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jedion357's picture
jedion357
January 27, 2011 - 6:08am
SFAndroid wrote:
.
Just get a TARDIS and tow the Earth around the Universe. Foot in mouth


Do you know where I can rent one of those TARDIS things?
I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers!

TerlObar's picture
TerlObar
January 27, 2011 - 4:49pm
I would have weighed in sooner but I've been swamped.

I think the article jedion is referring to is actually the Vector Movement article in issue 11 of the Star Frontiersman.  It is the movement system from Art Eaton's KH Vector rules.  It accurately represents true space physics for spacecraft movment in the KH game.  It's a little more difficult to play but not by much.  However, it completely changes the nature of the game as you really need to think about your speed direction more.

In response to the original post.  It would take 18 ADF in real life to make that maneuver as you would basically have to kill your 9 HpT of foward motion and generate 9 HpT in the other direction.  Based on the size of KH hexes one ADF if actually 2.78 g of acceleration and you would really need to pull 50g for that ten minute turn to pull it off.  (One of the thing's KHVector changes is the hex size.  If you make the hexes 3600 km instead of 10,000 km, then 1 ADF = 1g accleration). 

The KH boardgame rules were made (I assume) to look like naval or arial combat, not real space combat.  They're unrealistic from a "true physics" perspective but they're still fun.  The simple truth is the MR rating just doesn't make any realistic sense.  The ability to change your ship's direction in real life is only related to the strength of your main engines, in other words, your ADF.  You can change the pointing of your ship any way you want by maneuvering thrusters but unless you are firing your main engines you just keep going in the same direction (Newton's 1st law of motion).

@Ascent.  If you want help with the math, drop me a line with questions and I'll help you out.  I did the calculation once and you can rotate a battleship 180 degrees (i.e. turn around) on manevering thrusters in 90 seconds (I think. It was either that or 30 but I think 90 was the number for the battleship) and only experience about 0.5g of sideways acceleration from the rotation forces at the extreme ends of the ship.  Anything closer to the center of rotation would experience less.  For the smaller ships (up through LC I believe) you could whip around and face any direction in less than 30 seconds with no noticable effect.  I think I posted this somewhere on the starfrontiers.org forums.  I'll have to see if I can dig it up.
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Will the Stampede's picture
Will the Stampede
January 27, 2011 - 5:01pm
Honest Theta's Gently-Used Time Machines.

They have a Rani Special, complete with a cool mobile over the control console, one owner(11½ regenerations) only a hundred thousand millenia on the odometer, for the low, low, price of infinity minus one dollars.
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jedion357's picture
jedion357
January 27, 2011 - 5:55pm
Yes Vectored Movement

I've never played it but it would certainly be more in line with vectored movement

you need to keep MR simply for modifying the ships; it'd be the first point you'd blow off if you had to., because there can only be a difference of one between ADF and MR.

if you resize the hexes should we resize the ranges? for weapons?

I guess that would almost give you triple the range and make defenses of greater import. You's start to see people setting up their attack run and then "going to ground" with Ion window or a masking screen and coasting toward the enemy till optimum range then going full power and maneuvering against him. Would be a seriously different game.
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Tekrat04's picture
Tekrat04
January 28, 2011 - 3:42pm
I think we should stick to hand waving. Otherwise the numbers do not add up at all. An ADF of 1 is not a 1g maneuver it's a 1,667g maneuver for the full 10 minutes. The math is simple a=v/t. so 10,000,000m/s / 600s = 16,666.7m/s^2. If 1g = 10m/s^2 then 16,666,7m/s^2 = 1,666.67g. It's better to forget the real life physics and just enjoy the game. Steph

Gilbert's picture
Gilbert
January 28, 2011 - 6:45pm
  uh oh, someone made a big mistake on what 1 ADF is.

Will the Stampede's picture
Will the Stampede
January 29, 2011 - 12:19am
Unless, as I've mentioned in another thread, the designers confused acceleration with delta-v. If 1 ADF equals a delta-v of 16.666667 KPS, it would work out a little better.
" 'Beware the Beast, Man, for he is the Devil's pawn. Alone among God's primates, he kills for sport, for lust, for greed. Yea, he will murder his brother to possess his brother's land. Let him not breed in great numbers, for he will make a desert of his home and yours. Shun him; drive him back into his jungle lair, for he is the harbinger of death."

adamm's picture
adamm
January 29, 2011 - 7:22pm
Tekrat04 wrote:
I think we should stick to hand waving. Otherwise the numbers do not add up at all. An ADF of 1 is not a 1g maneuver it's a 1,667g maneuver for the full 10 minutes. The math is simple a=v/t. so 10,000,000m/s / 600s = 16,666.7m/s^2. If 1g = 10m/s^2 then 16,666,7m/s^2 = 1,666.67g. It's better to forget the real life physics and just enjoy the game. Steph


Wait a sec. I think you're missing a step in that calculation.

1ADF = 1 hex per turn per turn
= 10,000km / 10 min / 10min
= 10,000,000m / 600s / 600s
= 16666m / 600s / 1s
= 27.7m / 1s / 1s

and if we consider 1g to be 9.8m/s/s that makes 1ADF = 2.8g.

The acceleration is still pretty bad.  That ADF5 figher is pulling something like 14g's at full thrust and tremendously more if he's turning.  The rules do state that everyone has to be at their battle stations or they'll take damage during maneouvering.....so I just figure that everyone's battlestation is equipped with a form of protection we haven't invented yet.  Like a super high power inertia screen.

jedion357's picture
jedion357
January 29, 2011 - 8:07pm
So if we use adamm's suggestion the inertial compensator is not ship wide but workstation/chair wide probably powered directly from the engines and by implication able to handle upto 14gs. or fighters just get the most expensive version while other ships not expected to pull that much in gs get the compensators that will handle what they're expected to experience.

note that if this is the case the engineer will be issued a standard personal inertia screen for when he has to leave his station for battle repairs. its not enough but its still given to him as some little sop to maybe save his life.

Bad things would happen when battle damage takes this system out.
I might not be a dralasite, vrusk or yazirian but I do play one in Star Frontiers!

Ascent's picture
Ascent
January 31, 2011 - 6:12pm
Thanks, Terl.

The real problem is performing repairs during all this high-gee maneuvering. Inertia screen or not, that engineer has to fight against every gee in order to move. Inertia screens protect the body from the effects of inertia, they don't give the body a hand-wave pass to gravitational or inertial effects without anti-grav tech, which the Frontier doesn't have. So protection>yes, movement>no.

As for the issue of an easy mechanic to handle adjusting for g-force without a science calculator, that's what I'm working on. It will likely fudge a little, but the goal is to make it more realistic, not exactly perfect. I want to try and do so while preserving as much of the Knight Hawks mechanics as possible, even MR. The rules I'm working on will simply put limits upon ADF and MR, and perhaps give a little more direction on how and why MR is used. MR doesn't represent the ship's ability to maneuver through space in my mind, so much as a general summation of the limitations involved, wrapping up multiple factors into a single mechanic. when you put a cap on MR, involving degrees of the compass, rather than 6 hex sides, it should make more sense.
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adamm's picture
adamm
January 31, 2011 - 9:16pm
jedion357 wrote:

note that if this is the case the engineer will be issued a standard personal inertia screen for when he has to leave his station for battle repairs. its not enough but its still given to him as some little sop to maybe save his life.


That's a great point....I hadn't thought about the techs trying to work during all this.  The KH rules say that characters who aren't strapped in during combat take 1D10 damage for every ADF or MR the ship uses during that 10 minute turn.  An RS check allows you to take half damage and move 1/2 your walking speed.  Which implies failing the RS check makes the character immobile for that 10 minute turn.

This contradicts the entire existence of DCR and the damage control round, because nobody could be expected to make repairs while being battered to death.

It also says on the same page that 1ADF = 1g when it clearly can't given the size of a hex and length of a turn.  I think I want to rip this whole page out of the book and insert my own.