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Guest HC001ST - Stick

Slowing the Ship Down

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I am trying to design cfg/air files that approximate the behavior of a large ship. It weigh around 10-20 million tons, so I assume I will have to scale things down to something that fs2004 can handle.Starting with the template for a single engine aircraft (a Cessna 182), I have created a 100,000 lb ship and have calculated the MOIs using the ship dimensions (441' long X 57' wide X 37' deep). I am using an engine with a total displacement of 840 cubic inches. I have increased the parasitic drag scalar to 250. (This should not be excessive as water is 784 times as dense as air.) I have increased the thrust scalar to 7.5 and am using a fixed pitch prop with an angle of 5 degrees.As a result, the ship starts very, very slowly and behaves very sluggishly. It takes a bit too long to start moving (about a minute) and, once the ship starts moving, it zooms through the 0-20 knot range way too fast.Is there a way to speed up the initial movement of the ship and to slow down the zoom rate?Since induced drag starts off low and multiplies exponentially with an increase in speed, perhaps that is what I need. How do I change the coefficient of drag (Cd0) or the frontal area?The top speed of the ship also fluctuates wildly (e.g. from 30 kts to 15 kts and back in a matter of 10 seconds or so), despite the ship being a lot heavier. However, I assume that this is just a limitation of the program.Any insights are appreciated,Phil

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In the 5th paragraph of my previous post, I said: "Since induced drag starts off low and multiplies exponentially . . ."I meant to say parasitic drag, not induced drag. My ship is not going to be flying - at least I hope not.Phil

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Unfortunately, you'll have some real challenges doing this, as remember, all equations here come from "aerodynamics", and you are really dealing with water here which is a lot thicker.Frontal surface area is in the .air file, and can be edited easily with AirEd. Get the latest .ini for AirEd, and you'll be set.As MS removed "ground friction" and went to the air model, I think you are going to have significant challenges.You might want to consider creating a gauge that creates a sort of "fly by wire" situation, where your controls merely request velocity, and the gauge then manages the throttle to acheive the velocity indicated.Good luck

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