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Subject: 
Re: Hypothetical design question
Newsgroups: 
lugnet.space
Date: 
Wed, 25 Jun 2003 15:59:34 GMT
Viewed: 
876 times
  
In lugnet.space, David Laswell wrote:
   In lugnet.space, James Brown wrote:
   You’re misapplying inertia. The whole ship, including contents, has inertia. If it is moving, say, 1.25 Km/s (pretty darn quick) in arbitrary direction A, it (and all it’s contents will continue to move in direction A, and which direction it happens to be facing doesn’t mean diddly squat.

He does have a point as far as capital ships are concerned. A Starfury is a one-man ship, and everything I’ve seen suggests that when a Starfury rotates in flight, the cockpit is pretty darn near the center of rotation, so the pilot can withstand being quickly whipped around to face 180 degrees different. A capital ship, like the Hyperion, is gigantic, and whipping that type of ship around 180 degrees would involve a huge amount of G-force to anyone standing at either end of the ship, because their relative vector through space would change drastically during that manouver. Capital ships have to slowly adjust their trajectories (it should be noted that Star Trek starships use “inertial dampeners” as a way to cheat this fact of physics, while B5 starships show realistic mass behavior with huge capital ships taking a long time to alter course) or they will turn the crew into scrambled eggs.

Yup. But even a ship like the Hyperion could probably spin in place relatively quickly - certainly not at starfury-like speeds - but I imagine it could still do a 180 within a couple minutes. I strongly suspect, given the shape of Earthforce ships that the limiting factor is not actually what their crew can take, but what the structure will take. People can quite reliably take up to a couple G’s of acceleration, and rotating the end of the Hyperion at 1G (~9.8 m/s/s) will get it flipped about pretty quick.


  
   If it starts applying thrust, then it matters which direction it’s facing, but not until then.

And rotation without a change in trajectory still involves application of thrust, though I believe that even if a Starfury was flying at near-c speeds, the 180 degree snap-around manouver would not feel any different than if he was standing still. I’m also pretty sure that if it was flying at near-c speeds, and the pilot started applying slow thrust perpendicular to the trajectory, it wouldn’t feel any different than starting from a dead stop. Consider how fast Earth is hurtling through space, just as it revolves around the Sun (ignoring for now the Universe Expansion theory). Now that means that any orbital craft is traveling, on average (adjusting for which specific section of orbit it happens to be in), the same speed as Earth. That means that a modern spacecraft is travelling at immense speeds, but gently applying thrusters perpendicular to the overall direction of travel doesn’t really do any harm to the crew. It’s not how fast you’re travelling that matters. It’s how drastically you are changing your inertia that makes the difference. Slamming to a stop from near-c would be just as harmful as being catapulted from a dead standstill to near-c speeds. In the end, you experience the same amount of G-force.

Yup. It’s all about acceleration. :)

James



Message has 1 Reply:
  Re: Hypothetical design question
 
(...) The Hyperion (URL) lists> at about 1200 meters. Assuming the center of rotation is the exact center of the vessel, you're swinging 600 meters of steel around the point of rotation, and that's the critical point (after all, you want to make (...) (21 years ago, 26-Jun-03, to lugnet.space, FTX)

Message is in Reply To:
  Re: Hypothetical design question
 
(...) He does have a point as far as capital ships are concerned. A Starfury is a one-man ship, and everything I've seen suggests that when a Starfury rotates in flight, the cockpit is pretty darn near the center of rotation, so the pilot can (...) (21 years ago, 25-Jun-03, to lugnet.space, FTX)

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