Yes Case, that's what I'm getting at, that we have only touched the tip of the iceberg in truely comparing ships "by the numbers" with these max rotational velocities.

However, I would argue that even in engine-kill mode, the rotational acceleration plays a key factor.

I got the impression that engine kill does not provide for faster turns, it just provides for:

1. tighter turns
2. the opportunity to open up distance on your opponent

I don't get it folks. This stuff should be right in the .ini files just like everything else, so why hasn't it been extracted by somebody yet? The ships don't just magically perform like they do

Under normal mechanics (and its been years since I've studied this, so I'm probably very rusty) there would be a rotational inertia based on how the mass of the ship is distributed around its centre of gravity. Assuming that the mass of the ship was uniformly distributed throughout the structure, this would mean that a spherical ship would have the least rotational inertia with greater deviations away from this resulting in more inertia (basically, its the see-saw principal, where the turning effect = force x distance from pivot).

Now, based on the implied physics in the FL world, there is a peak rotational velocity that is achieved by a ship, and this is the nominal turn rate as described in the posts above.

I take your point that if there is significant inertia, i.e. if it takes any reasonable amount of time (say > 0.5 secs) to achieve this peak turn rate, then (assuming the Titan is more massive than the Sabre and has much higher inertia for example) rotational inertia would have a dramatic effect on the perceived agility of a ship.

This would be testable, as rotational inertia would be constant regardless of engine kill / no engine kill.

However, my current hypothesis is that a far bigger effect on turning comes from the velocity a ship has. When the direction of travel is changed, there is clearly some acceleration going on that attempts to maintain the magnitude of the original velocity, but in the direction of the new velocity. This was my comment about 'fly-by-wire' above - by re-pointing your mouse, you are effectively telling your ships thruster system where you want to go, and it is maintaining your current speed (i.e. magnitude of velocity) in the new direction.

For a more massive ship, i.e. one that has more inertia (not rotational inertia this time, but just straight-line inertia), the thrusters have to work much harder to maintain a constant speed through the turn. If they cannot exert enough thrust, then they have to take longer to complete the maneouvre (thrust = force x time if memory serves, so assuming a constant peak force, if thrust is insufficient you need to allow the force to act over a longer period of time).

To test this hypothesis, again you would compare the turn rate during engine kill vs. turn rate without engine kill but at high starting speed.

Of course, it could be that both inertial and rotational inertial effects apply; this would probably serve to make the Titan in our example feel even more sluggish.

The upshot is that the mass of the ship almost certainly has a big impact on turn rate, and possibly the shape and size of the ship matters too.

The reason I think that only 'normal' inertia applies is that I can see the developers as having modelled mass distribution across the different ships (although they could easily 'cheat' and create a variable for angular inertia which is used when turning).

As a rule of thumb from all this, I would say that the primary consideration for maneouvrability is the nominal turn rate, second would be the mass of the ship (which I think is part of the .ini) and third would be angular inertia (not sure if this is in or not)

tight case.. so basically we need another number added to that list- ship mass and a estimated turning rate created from it.. just reading the turn rates on idle ships is'nt gonna give up an accurate representation.. makes sense

Case,

I made some tests in a Dromedary a few weeks ago where I also tried turning at cruise speed. The result was exactly the same as with killed engines: 7 seconds per 360° rotation.

Hmm, looks like that blows my theory out of the water then [that there is some kind of fly-by-wire operating when you steer...

I think that the Defaultuser's idea that different ships have different angular acceleration makes a lot more sense in light of that observation. I would imagine that this has been implemented by giving each ship some kind of angular inertia co-efficient in the ini file, which combined with its mass would maybe indicate its propensity to turn?

I'm not an expert on ini files - has anyone checked out variables that look like drag co-efficients or similar?

Yeah Case, I've got even more fuel for the fire.

I just bought a Hammerhead out of curiosity. Blew my mind, cosidering what a disappointment the Centurion was in speed.

Measured rotation rate: 80 deg/s.
Feel of acceleration: faster than a Barricuda.

So, not only does it turn faster than the Barricuda, it also responds faster. Felt like I was flying a Falcon. Of course, we should expect this when we see similar hyjinks between the Hawk/Falcon.

It seems plain to me that there are seperate maximum angular velocities and angular accelerations, and that they aren't attached to the ship's characteristics in any way. This also allows for such out-of-place designs like the Wolfhound, which has neither armor, weapons or cargo space enough to justify it's pitiful 60 deg/s rotational rate.

The angular velocity measurement method is fine, but if we want any reliable numbers on angular acceleration somebody's going to have to dig them out of the ini files.

Ok, been digging through some ini files.

It seems that the following variables are used (bracket numbers are values for the Drake):

mass (100)
steering torque (25000)
angular drag (15000)
rotational inertia (3800)

Note that there are in fact 3 numbers for each variable apart from mass; 2 of these are the same, the third is usually different - I take this to be something to do with x, y and z axes maybe?

If you divide torque by drag and multiply by 60 degrees, you get the turn rate. No idea why its x 60 degrees per sec though. This appears to work quite well for all other ships.

Now, the interesting part of this is the torque divided by inertia. This should yield the acceleration (similar to F = ma, with torque being F, inertia being m; - I forget the rotational equivalent of the F=ma equation tbh)

This acceleration figure would contribute to perceived feel of the ship.

I'm not sure if the mass is explicitly factored into the rotational acceleration (it depends really if the rotation inertia value includes the mass within the overall value or not)

Gonna do some more digging I think

Ok,

dug out the stats for the titan, the sabre and the eagle.

titan and eagle both have mass = 150; sabre has mass = 75 (!)

eagle turn rate given by torque = 55000; drag = 41000; inertia = 8400 [ignoring different value for z axis

titan and sabre turn rate given by torque = 43000; drag = 41000; inertia = 8400

everyone seems to share the opinion that Sabre feels quicker than the Titan; this is probably explained by the difference in mass.

The eagle appears quickest because the extra mass over the Sabre (150 vs 75) is compensated for by the much higher torque

Interestingly, the Falcon and Eagle appear to share all characteristics, including mass.

From what I can tell, the patriot or drake should be the most agile ships in the game (drake has a higher inertia value than the patriot)

the hammerhead has similar characteristics to the eagle

I think the size of the ships may also impact on how they are perceived, particularly in terms of getting hit by the AI; this could complete the picture over perceived agiity (from personal experience, I always feel that a ship that gets hit less is more agile)

Case, you wrote:
"No idea why its x 60 degrees per sec though."

It may be an approximation to radians. Radians are used instead of degrees in most physics.

1 radian = 180 / pi degrees = approx. 57.3 degrees.