Rogue One Tech Discussion

For polite and reasoned discussion of Star Wars and/or Star Trek.
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2046
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Re: Rogue One Tech Discussion

Post by 2046 » Sun Apr 02, 2017 12:15 pm

Oh, I can make it even worse for you . . . note that upon the hammerhead ram, the shield ring thingy is well ahead of the two ISDs, but then the collision event continues until they're past the center of it. Then the disabled ISD is pushed seemingly straight down or maybe a tad backwards into the ring.

359
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Re: Rogue One Tech Discussion

Post by 359 » Sun Apr 02, 2017 5:26 pm

I plan on doing a more thorough analysis of the motion and impact, but let's do a quick overview. There are two Star Destroyers, one is without power and cannot maneuver and number two appears to be moving along its forward axis. Star Destroyer one is struck by the corvette which applies a force vector in the forward-lateral plane at an angle between the forward and lateral axes. The ship's moment of inertia should be located, by inspection, in the forward-vertical plane slightly up from the forward-axis and forward of the conn tower (in a regular square pyramid the inertial moment is located roughly 1/4 the way up from the base).

Let's start with the body's linear movement. We have an unbalanced force being applied along the positive lateral-axis (left) and to a lesser extent along the positive forward-axis. So we should expect acceleration in these directions.

Now let's look at the angular movement. We have an unbalanced force (once again) being applied along the positive lateral-axis (left) and to a lesser extent along the positive forward-axis. The force is located at a point forward, negative laterally, and negative vertically of the inertial moment of the body. We would expect this to create a large torque vector along the positive vertical-axis and a very small torque along the forward-axis.

This means that the ship should be moving left and forward while rotating with counterclockwise (from the top) yaw and counterclockwise roll (from the front) after the thrust. Which is very close to the movie, except we see clockwise roll (from the front).


Now the ships collide.


The initial collision starts aft and on the opposite side of the ship from corvette's thrust position and progresses forwards, but with the net collision vector always aft of the thrust. This creates an opposed force vector in the negative lateral direction. Also, because of the the second destroyer's forward motion, it will apply a force along the forward-axis transferring some of it's momentum through the collision.

Linearly, this will have the effect of increasing the forward motion (global forward, before rotation) and reducing the lateral motion (again global lateral) of the ship.

Angularly, this will increase the torque along the vertical axis, since the opposing (collision) force is aft of the thrust force and along the negative lateral-axis. Additionally, since the collision point is below the center of mass, we should see a torque vector along the negative forward-axis.

Now the ship should be moving less to the left and more forwards. We should also see an increase in it's yaw rotation rate counterclockwise, and less counterclockwise roll, possibly even clockwise roll.


These events match the film almost entirely. The only movements incorrect (in a general sense) is the clockwise roll of the Star Destroyer before the collision and *maybe* the counterclockwise pitch (from the left), but collisions are complicated, and there are explosions creating more forces, so there could be a cause, but I do not wish to investigate that at the moment.

Additionally the clockwise roll could actually be an initial tilt of the destroyer and just lateral movement, which upon further inspection of the scenes before it does appear to be. As the ship is struck with the ion torpedoes we see it make a small powered drift much like in ESB with the ion cannon shots.

Really what is most of interest to me is the thrust that the corvette was able to generate in order to create the initial movement of the destroyer. This implies some substantial acceleration abilities for that ship next to what we see from other Star Wars ships.

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Mr. Oragahn
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Re: Rogue One Tech Discussion

Post by Mr. Oragahn » Sun Apr 16, 2017 2:07 am

I think the lateral edge of an ISD is reinforced. The Hammerhead is stoped by both upper and lower rims. We see the opposite edge plow into what is clearly a non-armoured pile of levels of that tower section of the victimized ISD, although it's may be odd that there was enough momentum involved as to rip the entire tower off from its base.

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