Another reason for fast rotation is to prevent laser hits from burning through the hull.
CT Only: Inertial Compensation
- Thread starter infojunky
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infojunky
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Read the last line of my post....
Condottiere
SOC-14 5K
One issue with integrating it with the artificial gravitational plates would be potential latency.
It compensates after the force is felt.
It compensates after the force is felt.
infojunky
SOC-14 1K
Getting hit is still going to knock you around plain and simple. Compensation is just going cover the actions you take, not what is done to you.
AnotherDilbert
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Agreed, for all we know that would be the same thing.
You left out the Dragon article for CT...
coliver988
SOC-14 1K
one way intertial compensation could work is not as a reactive gravity force, but rather a field or bubble of localized gravity. This would not require tracking all external forces and reacting to them (similar to the way noise cancellation works as a parallel idea) but is simply a localized bubble that the external universe does not affect. Basically, it is all relative to the ship, regardless of what is happening to the ship.
I honestly never gave it any thought - just went with "it's science fiction so just works until it doesn't" sort of thing. I do enjoy reading all the posts though.
I honestly never gave it any thought - just went with "it's science fiction so just works until it doesn't" sort of thing. I do enjoy reading all the posts though.
BackworldTraveller
SOC-13
The arguments regarding inertial compensation make a couple assumptions
1) That acceleration is along one axis only. Taking T5 as the most explicit example, the acceleration can be varied to operate laterally, etc. With a single grav module, that is a big problem unless that module is at the centre of mass of the vessel: As the direction is varied, a spinning moment is created. If a single set of grav plates at the front of the vessel provides the compensation that could be interesting for the crew. (Landing on a larger body suggests there can't be just one axis to compensate for - an acceleration of 1G sternwards that resolves as a perceived gravity of 1G floorwards also needs to take into account planetary gravity). Most of the designs in Traveller put the manoeuvre drive in a room at the stern and don't take into account those twisting forces.
2) That acceleration is provided only by the manoeuvre drive. There are many other accelerations provided by the hull itself when it operates in an atmosphere and aerofins only add to those abilities. Thus the compensation needs to overcome these effects too if acceleration is to be imperceptible. Turbulent air currents will remain a problem - especially with users of basic sensors.
1) That acceleration is along one axis only. Taking T5 as the most explicit example, the acceleration can be varied to operate laterally, etc. With a single grav module, that is a big problem unless that module is at the centre of mass of the vessel: As the direction is varied, a spinning moment is created. If a single set of grav plates at the front of the vessel provides the compensation that could be interesting for the crew. (Landing on a larger body suggests there can't be just one axis to compensate for - an acceleration of 1G sternwards that resolves as a perceived gravity of 1G floorwards also needs to take into account planetary gravity). Most of the designs in Traveller put the manoeuvre drive in a room at the stern and don't take into account those twisting forces.
2) That acceleration is provided only by the manoeuvre drive. There are many other accelerations provided by the hull itself when it operates in an atmosphere and aerofins only add to those abilities. Thus the compensation needs to overcome these effects too if acceleration is to be imperceptible. Turbulent air currents will remain a problem - especially with users of basic sensors.
AnotherDilbert
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No, not really.
Even if we cannot vector the grav field, we can presumably superimpose grav fields in different directions to get a resulting grav field in any desired direction. Something like this:
The black resulting grav field is the sum of the red and green grav fields. By varying the strengths of the components we can get any resulting vector we want.
With an accelerometer or gyro stabiliser and a control system we can cancel out any perceived acceleration in any direction. In the same way that noise-cancelling headphones can cancel out any noise (rather imperfectly).
mike wightman
SOC-14 10K
You are assuming that:
artificial gravity- grav plates
maneuver thrust - m-drive
inertial compensation - acceleration compensators
are all variations of the same technology.
There is no evidence for this, but it does make sense.
This is a typical quote:
artificial gravity- grav plates
maneuver thrust - m-drive
inertial compensation - acceleration compensators
are all variations of the same technology.
There is no evidence for this, but it does make sense.
This is a typical quote:
note, lateral G forces, like those suffered by aircraft turning.
Not exactly, but close. Aircraft turning generally bank into the turn, so the net effect is perceived as increased vertical acceleration.
The thing that makes it a bit more complicated is roll/yaw/pitch maneuvers.
Consider the FASA Type T Patrol Cruiser -- 75m long (in the illustration, not the stubbier FASA deck plans, as I worked out in my Type T Deckplans, Fixed thread)
It's 75m long and the likely center of mass is about where the aft turrets are, so the bridge is about 37m ahead of that. How much off-axis (pitch, yaw, roll) thrust can the drives provide? If it's 2G (out of 4G), that's maybe 2.5G at the bridge from the nose going the opposite direction from the off-axis thrust (ship pivots on the center of mass, bridge has a longer lever arm than the drives do) -- not counting the "centrifugal" force of the rotation because I don't want to do that math right now...
Which also suggests that the inertial compensation can handle a few Gs (apparent) vertical without serious effects, so if it's doing its 4Gs in atmosphere and using the wings to trade acceleration Gs for extra Gs of aerodynamic lift, it still won't overload the ship's internal gravity control systems. (Might make a difference in my Play-by-Post at some point if I can ever get off my backside and get the plot moving again... )
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AnotherDilbert
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Yes, the original mention in HG, and the techobabble in CT Striker and MT, says so. There is only one basic a-gravity technology, perhaps with different implementations for different purposes.
The original definition is:
The grav plates makes interior gravity normal, presumably regardless of normal manoeuvres, i.e. both "artificial gravity" and "inertial compensators".
No, that is a separate but related tech according to the same technobabble.
How the drive thrust is generated is irrelevant to the inertial compensators, it could just as well be a rocket as an M-drive (or heretical HEPlaR).
Yes:
So couteracts perceived acceleration (within reason) in any direction? The italicised sentence seems to say so.
Note that we can't have any "lateral G forces" in space without an atmosphere to push against.
AnotherDilbert
SOC-14 1K
What I think Mike is suggesting is that we can use the wings to push against the atmosphere to make sharp turns of much more than 6 G. Depending on TL inertial compensators should not be able to handle all of that, so some of it would not be counteracted and hence felt by the passengers.
Of course we can't do that in space as there is no atmosphere there, though.
Yes you can, as my example demonstrated. I'm going to have to do the math after all, aren't I?
Type T, as above. Radius 37m at the bridge. 1 second of 2G acceleration provides 20m/sec tangential velocity (understated, as the drives have a shorter lever arm than the bridge). Centripetal force required (inverse of centrifugal force pushing the bridge crew to the nose of the ship) is 1.024G if I plugged everything in correctly. (SpinCalc at artificial-gravity.com)
Circumference is 2*pi*r, or ~232.5m. This means that at 20m/sec, 1 rotation about the center of mass takes 11 seconds, for 5.17 RPM -- this is likely sufficient to induce vertigo... (I'm assuming only a single 1-second 2g impulse rather than constant acceleration/deceleration, so the forces are likely understated. I've probably oversimplified and missed something in here, but I think it's in the ballpark.)
Condottiere
SOC-14 5K
There's probably a reason most commercial shipping doesn't exceed acceleration factor three.
If it's microbeams built into the onboard artificial gravitational plating, it would need to be three sixty degrees coverage, so that plating would be built into the walls as well, and long corridors would be health hazards.
If for some reason compensation doesn't suffer latency.
If it's microbeams built into the onboard artificial gravitational plating, it would need to be three sixty degrees coverage, so that plating would be built into the walls as well, and long corridors would be health hazards.
If for some reason compensation doesn't suffer latency.
AnotherDilbert
SOC-14 1K
That's not lateral (sideways) acceleration, that's rotational acceleration.
Lateral acceleration is linear acceleration to the side, i.e. not in the direction of the main drive.
AnotherDilbert
SOC-14 1K
Cost.
infojunky
SOC-14 1K
Then there is the fact that gets lost here, 1g is blinding amount of thrust... High end jet fighters only have around 1g of thrust.
AnotherDilbert
SOC-14 1K
Agreed, 1 G is a lot. Many commercial ships would be quite happy with 0.5 G or even 0.1 G...
The only reason for 2 G that I see is if you want to land on the drive alone on hi-grav worlds. The difference in time to a normal 100 D limit is negligible.
More than 2 G is for combat advantage.
