Wed Oct 18, 2006 7:46 am
Speed calculations
Dear community,
as I play the vanilla version of freelancer without any mods I wanted to know which of the ships has the fastest turning speed. My first approach to this problem was to try all the ships and compare them by only flying.
The most obvious fact is that the Drake seems to be the quickest ship concerning handling. But the other ships (not freighters) are very hard to compare. For example Hammerhead vs. Eagle. (Sometimes you think one is faster than the other and sometimes not)
Therefore I downloaded FL DataStorm and figured out that all ships have the following specs:
- turning_torque
- angular_drag
- rotation_inertia
I have found many discussion concerning the ship handling and the people found out results of turning speed in deg/sec. This made me think about the topic from a physical background.
I tried to relate the three main aspects of the ships and in regard to the physical formulas and laws I figured out the following formulas for the handling.
1. Turning_torque
The turning_torque as the name says is the torque for turning the ship around its axis. There the unit has to be Nm.
2. Angular_drag
This should be the angular drag that should avoid the ship from moving faster and faster. Angular drag only affects the turning not the linear movement. So far I have not figured out the correct unit of this spec yet.
3. Rotation_inertia
This last spec should affect the beginning of a initiated turn. If the rotation inertia is high the ship movement begins slower until it reaches the max. angular speed. The unit of the rotation inertia is kgm².
Now my calculation.
(I learned physics in Germany therefore I will not use English indexes)
According to Newton's 2 law the force is F=m*a.
F = force
m = mass
a = acceleration
This law only applies to linear movement. For rotation the correct formula is:
M=J*aplha
M = torque = turning_torque
J = rotation inertia = rotation_inertia
aplha = angular acceleration
From this formula we can derive the ship's acceleration for the rotation.
M/J=alpha
The unit is rad/(sec^2) and has to be transformed to deg/(sec^2).
The calculations for the turning speed are a bit more complicated as I haven't found out the correct formulas yet. My suggestions is:
M/angular_drag = turning speed
The only input for the formula is the torque M which is in Nm. The resulting turning speed has to be in rad/sec or deg/sec after a transformation.
After having calculated the turning speeds and after the transformation into deg/sec I figured out that my results do exactly match to the ship FAQ by Starman Omega.
As I made my exam in physics I search for a formula which shows that these calculations for the turning speed are correct.
Regarding the SI-units of the last formula I have the following suggestion:
input:
1 Nm = 1 kg*m²/s²
output:
1 rad/sec = 1/sec
The input has to be divided by 1 kg*m²/s to have the output result. This means that Nm has to be divided by Nm*s.
The best formula I made myself is M = d*(d(phi)/dt)
M = torque
d = angular_drag
d(phi)/dt = angle / s = angular speed
The reason I write all these formulas is to have a physical background to the movement of the ship because the developers already used these physical laws. Second, I want to have a calculated turning speed and not an estimated speed.
I typed all the formulas into an excel sheet which can be found here:
Freelancer Ships - Excel sheet
If anybody is a physics expert I ask for a look on my thoughts if they are correct.
Edited by - Paulovic on 10/18/2006 9:18:03 AM
as I play the vanilla version of freelancer without any mods I wanted to know which of the ships has the fastest turning speed. My first approach to this problem was to try all the ships and compare them by only flying.
The most obvious fact is that the Drake seems to be the quickest ship concerning handling. But the other ships (not freighters) are very hard to compare. For example Hammerhead vs. Eagle. (Sometimes you think one is faster than the other and sometimes not)
Therefore I downloaded FL DataStorm and figured out that all ships have the following specs:
- turning_torque
- angular_drag
- rotation_inertia
I have found many discussion concerning the ship handling and the people found out results of turning speed in deg/sec. This made me think about the topic from a physical background.
I tried to relate the three main aspects of the ships and in regard to the physical formulas and laws I figured out the following formulas for the handling.
1. Turning_torque
The turning_torque as the name says is the torque for turning the ship around its axis. There the unit has to be Nm.
2. Angular_drag
This should be the angular drag that should avoid the ship from moving faster and faster. Angular drag only affects the turning not the linear movement. So far I have not figured out the correct unit of this spec yet.
3. Rotation_inertia
This last spec should affect the beginning of a initiated turn. If the rotation inertia is high the ship movement begins slower until it reaches the max. angular speed. The unit of the rotation inertia is kgm².
Now my calculation.
(I learned physics in Germany therefore I will not use English indexes)
According to Newton's 2 law the force is F=m*a.
F = force
m = mass
a = acceleration
This law only applies to linear movement. For rotation the correct formula is:
M=J*aplha
M = torque = turning_torque
J = rotation inertia = rotation_inertia
aplha = angular acceleration
From this formula we can derive the ship's acceleration for the rotation.
M/J=alpha
The unit is rad/(sec^2) and has to be transformed to deg/(sec^2).
The calculations for the turning speed are a bit more complicated as I haven't found out the correct formulas yet. My suggestions is:
M/angular_drag = turning speed
The only input for the formula is the torque M which is in Nm. The resulting turning speed has to be in rad/sec or deg/sec after a transformation.
After having calculated the turning speeds and after the transformation into deg/sec I figured out that my results do exactly match to the ship FAQ by Starman Omega.
As I made my exam in physics I search for a formula which shows that these calculations for the turning speed are correct.
Regarding the SI-units of the last formula I have the following suggestion:
input:
1 Nm = 1 kg*m²/s²
output:
1 rad/sec = 1/sec
The input has to be divided by 1 kg*m²/s to have the output result. This means that Nm has to be divided by Nm*s.
The best formula I made myself is M = d*(d(phi)/dt)
M = torque
d = angular_drag
d(phi)/dt = angle / s = angular speed
The reason I write all these formulas is to have a physical background to the movement of the ship because the developers already used these physical laws. Second, I want to have a calculated turning speed and not an estimated speed.
I typed all the formulas into an excel sheet which can be found here:
Freelancer Ships - Excel sheet
If anybody is a physics expert I ask for a look on my thoughts if they are correct.
Edited by - Paulovic on 10/18/2006 9:18:03 AM