Re: Anti grav technology
- Thread starter Hecateus
- Start date
Granpafishy
SOC-12
Dr John Cramer writes a column on advanced physics, available on-line. All worth reading, thisis one on antigravity.
http://www.npl.washington.edu/AV/altvw83.html
Dr Robert L. Forward has written INDISTINGUISHABLE FROM MAGIC, a terific book of advanced physics by world-famous physicist who is also a SF author.
I prefer his special-relativity solution, but it is not really Traveller-like.
http://www.npl.washington.edu/AV/altvw83.html
Dr Robert L. Forward has written INDISTINGUISHABLE FROM MAGIC, a terific book of advanced physics by world-famous physicist who is also a SF author.
I prefer his special-relativity solution, but it is not really Traveller-like.
Thanks for the links, but I was wondering more if there was more or less any official traveller explanation. So far it just sounds like one big handwave. I have many questions which i feel should be resolved:
1. I can't seem to find anywhere in the t20 book (only one I got) as to whether or not 'gravity deck plating ala 'Star Wars/Trek' exists...or if the ships rely on raw acceleration to create the same. I understand there are inertial dampening systems and gravitic drives to manage as much...but without plating, then only centifical(sp) force keeps PCs on deck during jump periods.
2. How is it assumed that Gravity manouever Drives work...are these the same as anti-grav vehichles?
3. Why do ships have these at the rear? Why do they look like chemical reaction nozzes
4. Is there any correlation between the above things with the Jump Drives?
5. If there is gravity plating, what happens to prevent two nearby ships from colliding if they lose power to their manouever drives, but not the plating?
1. I can't seem to find anywhere in the t20 book (only one I got) as to whether or not 'gravity deck plating ala 'Star Wars/Trek' exists...or if the ships rely on raw acceleration to create the same. I understand there are inertial dampening systems and gravitic drives to manage as much...but without plating, then only centifical(sp) force keeps PCs on deck during jump periods.
2. How is it assumed that Gravity manouever Drives work...are these the same as anti-grav vehichles?
3. Why do ships have these at the rear? Why do they look like chemical reaction nozzes
4. Is there any correlation between the above things with the Jump Drives?
5. If there is gravity plating, what happens to prevent two nearby ships from colliding if they lose power to their manouever drives, but not the plating?
Granpafishy
SOC-12
(All answers based on my knowledge of the system)
1. Inertial compensation is also grouped with Artificial Gravity.
2. They are exactly the same. Thruster Plates extend the range from 10 diameters to 100 diameters (Sufficent for jump)
3. Don't have a clue. I place the ones I design spaced throughout the ship.
4. I don't think so.
5. I don't think that has been addressed in connon.
Here's another question; If they can create artificial gravity, why can't they create a drive that either pulls or pushes the ship along?
1. Inertial compensation is also grouped with Artificial Gravity.
2. They are exactly the same. Thruster Plates extend the range from 10 diameters to 100 diameters (Sufficent for jump)
3. Don't have a clue. I place the ones I design spaced throughout the ship.
4. I don't think so.
5. I don't think that has been addressed in connon.
Here's another question; If they can create artificial gravity, why can't they create a drive that either pulls or pushes the ship along?
far-trader
SOC-14 10K
Also from my distilled collective memory of Traveller versions over the years with my own twists...
IMTU the artificial gravity and inertial dampers are a field side effect of the maneuver drive. The maneuver drive also includes the ContraGrav lift effect. Essentially the maneuver drive while operational generates a field using the lanthanum hull grid. Why the (jump) grid? Well it is a part of every craft design by default, or else externally mounted small craft couldn't be safely carried through jump by starships. So it must have another purpose or it wouldn't be needed by small craft that would always be in a hanger or simply used in one stellar system. Within the field (rapidly dropping off beyond the hull grid) the only acceleration effect felt is the 'down' of the artificial gravity. This artificial gravity plane is set and fixed in orientation when the hull is laid but can be manipulated in strength up to the G rating of the drive independantly with the right software. Normally it is set to automatically cancel the crafts accelerations as an inertial damper effect. Your biggest worry is the computer control being lost, you could still maneuver but any damper effect would be lost. The artificial gravity field has a hardwired default of 1G 'down' so that's a little less of a worry until the maneuver drive or powerplant is off line too.
IMTU they are closely related but not identical. Vehicle grav drives are only good within a strong gravity field, pushing against the field. They are useless in microgravity so no interplanetary trips but you can just make low 'orbit'. Also vehicle grav systems do not negate outside gravity so you still feel acceleration, including local gravity. Additionally if you run over someone or something with a 2 tonne grav-truck its the same as running over the person or object with a wide tracked 2 tonne vehicle, squish! Craft grav drives instead cut off the craft from gravity and can manipulate up to the G rating in any direction desired. One benificial side effect of being cut off from gravity is there is no crushing effect below the ship as long as the maneuver drives are operational. Another are the above described artificial gravity and inertial damper effects.
IMTU they are the heat exhaust end of the maneuver drives, its usually better to keep it at the rear though they could be mounted anywhere on the exterior. The actual thrust is generated by the maneuver drive acting on the universe's gravity through the field. The maneuver drive is usually attached directly to the exhaust plates to save volume and cost, though a custom design could seperate them.
Hope that helps a bit. Not exactly the answer you were hoping for I expect but there are so many possible canon answers, most of which raise more questions than they answer.
Glossed over in CT (and T20 it seems), detailed better in later versions, including spin gravity.
IMTU the artificial gravity and inertial dampers are a field side effect of the maneuver drive. The maneuver drive also includes the ContraGrav lift effect. Essentially the maneuver drive while operational generates a field using the lanthanum hull grid. Why the (jump) grid? Well it is a part of every craft design by default, or else externally mounted small craft couldn't be safely carried through jump by starships. So it must have another purpose or it wouldn't be needed by small craft that would always be in a hanger or simply used in one stellar system. Within the field (rapidly dropping off beyond the hull grid) the only acceleration effect felt is the 'down' of the artificial gravity. This artificial gravity plane is set and fixed in orientation when the hull is laid but can be manipulated in strength up to the G rating of the drive independantly with the right software. Normally it is set to automatically cancel the crafts accelerations as an inertial damper effect. Your biggest worry is the computer control being lost, you could still maneuver but any damper effect would be lost. The artificial gravity field has a hardwired default of 1G 'down' so that's a little less of a worry until the maneuver drive or powerplant is off line too.
Canonically vehicle systems only work up to orbit while craft systems continue to work beyond.
IMTU they are closely related but not identical. Vehicle grav drives are only good within a strong gravity field, pushing against the field. They are useless in microgravity so no interplanetary trips but you can just make low 'orbit'. Also vehicle grav systems do not negate outside gravity so you still feel acceleration, including local gravity. Additionally if you run over someone or something with a 2 tonne grav-truck its the same as running over the person or object with a wide tracked 2 tonne vehicle, squish! Craft grav drives instead cut off the craft from gravity and can manipulate up to the G rating in any direction desired. One benificial side effect of being cut off from gravity is there is no crushing effect below the ship as long as the maneuver drives are operational. Another are the above described artificial gravity and inertial damper effects.
Canonically, because they look Buck Rogers(tm) cool? Some descriptions have that what you see are the drive plates and a ring of directional plates. Kind of like the thrust nozzels on jets but to direct the gravitons or what ever to change the crafts direction of thrust.
IMTU they are the heat exhaust end of the maneuver drives, its usually better to keep it at the rear though they could be mounted anywhere on the exterior. The actual thrust is generated by the maneuver drive acting on the universe's gravity through the field. The maneuver drive is usually attached directly to the exhaust plates to save volume and cost, though a custom design could seperate them.
IMTU yes. See above. Canonically I don't recall any correlation.
Impossible IMTU for the reasons above. Canonically I've not seen any description. If IYTU this is a possible problem I wouldn't worry too much since the gravitational effect would be very minimal and the distances, even in close combat in space are vast. If two ships were docked or docking there might be some small effect, no big crash, more of a grinding together until the hulls are in contact imo.
Hope that helps a bit. Not exactly the answer you were hoping for I expect but there are so many possible canon answers, most of which raise more questions than they answer.
Andrew Boulton
The Adminator
Yes, they have grav plates.
They work very well
There are two separate components, contragrav and thrusters. Contragrav negates any nearby gravity field, making grav vehicles or ships hover. Thrusters push against the field, providing thrust. Ships use thrusters, vehicles may use them or something else.
Because.
No.
The effect is very short range.
mike wightman
SOC-14 10K
Originally posted by Hecateus:
1. I can't seem to find anywhere in the t20 book (only one I got) as to whether or not 'gravity deck plating ala 'Star Wars/Trek' exists...or if the ships rely on raw acceleration to create the same. I understand there are inertial dampening systems and gravitic drives to manage as much...but without plating, then only centifical(sp) force keeps PCs on deck during jump periods.
With the understanding that I know CT not T20
Yes, there are grav plates in the deck. Centripital force has no effect unless you're spinning.
2. How is it assumed that Gravity manouever Drives work...are these the same as anti-grav vehichles?
The CT maneuver drive was not defined, wisely. In the 1970s we assumed it was some kind of "Dean drive", today perhaps a version of Woodward's Machs Principle drive. CT/Striker assumes that contragrav is different from maneuver drive. Maneuver drives operates irrespective of local gravity and are much more expensive.
3. Why do ships have these at the rear? Why do they look like chemical reaction nozzes
Mostly artistic licence. IMTU they radiate waste heat.
4. Is there any correlation between the above things with the Jump Drives?
Not in CT or IMTU
5. If there is gravity plating, what happens to prevent two nearby ships from colliding if they lose power to their manouever drives, but not the plating?
IMTU the deck gravity runs from plates in the overhead to plates in the deck, (pressing from the overhead, pullingto the floor) so there is only "leakage" outside the ship. I know it doesn't make much sense, but shipboard gravity is the most far-fetched of Traveller's technologies anyway.
1. I can't seem to find anywhere in the t20 book (only one I got) as to whether or not 'gravity deck plating ala 'Star Wars/Trek' exists...or if the ships rely on raw acceleration to create the same. I understand there are inertial dampening systems and gravitic drives to manage as much...but without plating, then only centifical(sp) force keeps PCs on deck during jump periods.
With the understanding that I know CT not T20
Yes, there are grav plates in the deck. Centripital force has no effect unless you're spinning.
2. How is it assumed that Gravity manouever Drives work...are these the same as anti-grav vehichles?
The CT maneuver drive was not defined, wisely. In the 1970s we assumed it was some kind of "Dean drive", today perhaps a version of Woodward's Machs Principle drive. CT/Striker assumes that contragrav is different from maneuver drive. Maneuver drives operates irrespective of local gravity and are much more expensive.
3. Why do ships have these at the rear? Why do they look like chemical reaction nozzes
Mostly artistic licence. IMTU they radiate waste heat.
4. Is there any correlation between the above things with the Jump Drives?
Not in CT or IMTU
5. If there is gravity plating, what happens to prevent two nearby ships from colliding if they lose power to their manouever drives, but not the plating?
IMTU the deck gravity runs from plates in the overhead to plates in the deck, (pressing from the overhead, pullingto the floor) so there is only "leakage" outside the ship. I know it doesn't make much sense, but shipboard gravity is the most far-fetched of Traveller's technologies anyway.
Lets do a little math shall we?
Assume that the artificial gravity goes right through the hull of the ship just like natural gravity. Assume as well that the starship is 20 meters in diameter or 10 meters in radius.
Gravity obeys the inverse square law, this means that with a planet gravity is very long range. Earth's gravity is 1 G at the surface, 1/4th G at 4000 miles altitude and 1/16th G at 12000 miles altitude or 16000 miles from the center of the Earth.
With a 10 meter diameter space ship, the gravity is 1 G at the ship's surface, and 1/4 G 10 meters from the ship, or 20 meters from its center. The gravity is 1/16th G 30 meters from the ship's hull. So even if you assume regular gravity, gravity for small ships is a short range force. Antigravity is too supposedly.
An anti-grav vehicle would work as follows:
Lets say the vehicle masses 1 ton, and below the vehicle a slab of ground 1 meter thick, 2 meters wide and 4 meters long also masses 1 ton.
If the antigrav vehicle projects an antigrav force of -1 G below the vehicle, it will push that one ton of ground down and by Newton's law of motion push itself up just off the ground. The vehicle is of similar dimension as that slab of ground it pushes, so to rise 1 meter off the ground it will have to project -4 G of antigravity, to ascend to 2 meters, it needs -16 Gs of antigravity. Of course if the planet also has an atmosphere it can also push on the air and it can ascend to a certian altitude or it can build up enough speed to coast into orbit, but on a vaccum world it can probably hover only a few meters off the surface since their is no air to push. Now does this sound like an air/raft to you?
