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efreysson
04-07-2016, 02:48 PM
I'm writing a sci-fi space battle, and I was wondering if a fighter pilot would experience g-force when making sharp turns at high speed.

Anyone know?

WeaselFire
04-07-2016, 05:12 PM
G-force, which is the force exerted on an object in motion when direction or speed of that motion changes, or the force exerted by gravitational pull (hence the name and unit of measurement), exists with or without the presence of gravity. So your answer is yes.

Now, take a look at a starship, maybe one named Enterprise, with a captain and crew out exploring new... Okay, the Star Trek thing. Traveling at or above the speed of light, coming to a full stop. The forces on the bodies in the ship would turn them into stains on the walls, if the walls even held together. The creators of the series (and most SciFi writers prior to that point) invented a way around this. In the case of Star Trek it is the inertial dampener, a mysterious device that overcomes this force so faster than light travel is actually survivable.

Fortunately, technology has adapted to g-forces in fighters as well as current spacecraft, so that the force is survivable. Your pilots would surely be taught how and would be using the proper equipment. So it depends on what you need for your story. Have them feel it, ignore it completely or find a way for the safety equipment to fail if you need them to black (or red) out or even die.

Jeff

Common
04-07-2016, 05:16 PM
What Jeff said. Inertial dampeners would be a way to explain the plausibility. You don't really need to go in to the details of it to make it work.

robjvargas
04-07-2016, 05:29 PM
Some authors make the "engine" a field effect. It applies thrust and propulsion to every single speck of matter within the field. Not to objects like a ship. As a result, no G-forces impact pilots, crew, passengers, etc.

Of course, even a .0001% variance at 1300 lights would be... problematic.

mirandashell
04-07-2016, 06:03 PM
Can a ship in space make sharp turns?

efreysson
04-07-2016, 06:13 PM
Can a ship in space make sharp turns?

Can ships travel faster than light? No. But it's space opera, so I can get away with stuff like that. :)

I appreciate the input, you guys.

mirandashell
04-07-2016, 06:14 PM
Well, if you are going to have your ships behave like spitfires in space, why are you worrying about g-force? You're already handwaving the major problem.

onesecondglance
04-07-2016, 09:00 PM
Miranda's right, though. You don't have air pressure to "bank" with, so first you need to stop moving in the direction you were originally travelling (without inertia to help you), then start moving in the other direction. You don't so much "turn" as change vectors...

morngnstar
04-07-2016, 09:30 PM
Space vehicles move in smooth curves as much as air vehicles do, just for different reasons. Hohmann transfer orbit, for example. Coming to a stop is unnecessary. The only thing about executing a "bank" in space is that your rocket has to fire perpendicular to your course. So it might look different than a bank in air, with the nose pointing inward, assuming it has a nose and is otherwise laid out like a jet plane, but the same flight path and G-forces are possible.

mirandashell
04-07-2016, 09:41 PM
Hmmm... it's true that you don't have to come to a stop but you don't bank. It's more of a 'flip' into a different direction.

Spaceships do not do what Spitfires do. You can't have dogfights in them. No matter what they do in Star Wars and BSG.

blacbird
04-07-2016, 09:50 PM
It was for the crew of Apollo-13 when the accident happened and it went into a rapid spin.

caw

Common
04-07-2016, 09:51 PM
We may be getting in to this a little too deep but maybe the engines themselves move. Almost like a rutter on a ship but instead of changing course by directing the drag, it changes direction by changing how the force is applied to it. A better analogy would be like a propeller on a small boat. Turning the wheel turns the motor, not the boat. (Well it does but the motor turns the boat)

mirandashell
04-07-2016, 10:14 PM
It was for the crew of Apollo-13 when the accident happened and it went into a rapid spin.

caw

I assume you're referring to g-force? I agree. Which is why was I amused that the OP asked about the g-force when he's already hand-waving what is to me a much bigger issue.

But what the hey. It's not my book.

morngnstar
04-07-2016, 10:23 PM
Hmmm... it's true that you don't have to come to a stop but you don't bank. It's more of a 'flip' into a different direction.

Meaning a roll? But that won't change the direction you're moving, just the direction you're pointing. It's easy enough to point a different direction than you're moving in space. To change the direction you're moving, you have to fire your engines. And that will result in a path that's a smooth curve. I'm not sure what you two are trying to describe, but sometimes it sounds like turning a corner, which definitely will not happen in space.


Spaceships do not do what Spitfires do. You can't have dogfights in them. No matter what they do in Star Wars and BSG.

I've heard this, but I think the reason has little to do with whether they can bank or not. It has to do with the huge distances and speeds that likely would be involved. You'd see your enemy as a speck on the (figurative) horizon, and a split-second later they'd pass you by.

Modern aircraft don't really fight like Spitfires either, for the same reason. You pick out your enemy on radar, target it with your computer, and fire a guided missile.

mirandashell
04-07-2016, 10:31 PM
I'm not sure how you equate a flip with a roll.

Look, there's load of stuff about this on the internet if you want to research it. And the OP asked about sharp turns. That's what I was referring to when I mentioned banking and dogfights. How far away the enemy is didn't really come into it.

morngnstar
04-07-2016, 10:48 PM
I'm not sure how you equate a flip with a roll.

I don't know. I didn't really have any idea what a flip would mean. You tell me.

mirandashell
04-07-2016, 11:01 PM
Like I said, there's lot of stuff on the internet. Seeing as you are talking about something the OP didn't ask about, I suggest you do some research before saying anything else.

And I'm done.

kuwisdelu
04-07-2016, 11:17 PM
g-forces are just acceleration. Any kind of acceleration will cause them. Changing direction requires acceleration, regardless of how its performed.

Cath
04-07-2016, 11:24 PM
Gently, all.

kuwisdelu
04-07-2016, 11:39 PM
Gently, all.

That would cause less g-forces, yes.

Common
04-08-2016, 12:02 AM
That would cause less g-forces, yes.

I see what you did there.

WriterDude
04-08-2016, 12:47 AM
I'm writing a sci-fi space battle, and I was wondering if a fighter pilot would experience g-force when making sharp turns at high speed.

Anyone know?

It comes down to the level of tech you're writing. If you've got faster than light travel and artificial gravity, there's no reason to suppose that external forces on a pilot can't be eliminated within the craft.

Otherwise the forces are what you'd find on earth as inertia and momentum are universal.

For some decent realism in space combat, watch babylon 5.

robjvargas
04-08-2016, 01:01 AM
Hmmm... it's true that you don't have to come to a stop but you don't bank. It's more of a 'flip' into a different direction.

Spaceships do not do what Spitfires do. You can't have dogfights in them. No matter what they do in Star Wars and BSG.
No, but the human body *does* respond differently to g-forces from different directions. An up/down vector can be withstood to higher levels than side to side. And, frankly, an upside down vector (relative to the pilot) might be the least survivable; as in gees being directed up from feet to the head. I don't know about that for sure though.

So... banking wouldn't be needed for the performance of the craft. But for the survival of the pilot...

mirandashell
04-08-2016, 01:07 AM
I was going to reply to the above but I think I will go until the thread has some realistic science.

Sorry Cath. I'm off.

morngnstar
04-08-2016, 02:35 AM
We're all talking about different methods of turning sharply in space, or whether it's possible at all. But to get back to the original question, regardless of how you do it, if you do it, yes there will be G forces.

If you are
- going fast
- change direction significantly
- in a short span of time
then there will be high G forces, using any currently known technology. Technomagical inertial dampers and such exempt.

King Neptune
04-08-2016, 04:02 AM
The way that I like to think of such maneuvers is as the addition of vectors. The g-force would be related to the delta V, change in velocity. If something is moving at two hundred units, and you want to reverse the direction and have it go in the opposite direction at the same speed, then you will have to apply enough force to overcome the present momentum and give it that much more momentum in the other direction. A rider would feel that, unless you decided to spend two years doing the maneuver. If you want to turn it twenty degrees to port, then it won't take nearly as much force, and it won't be felt as strongly.

It isn't practical to have tight maneuvers in space warfare. A few authors have described turns that took months to complete and using high energy missiles that were aimed at places where the opponent would have to be in a few months. If you predict location correctly and aim well, then you win; otherwise maybe not.

kuwisdelu
04-08-2016, 04:06 AM
A rider would feel that, unless you decided to spend two years doing the maneuver.

Maybe that's how inertial dampeners work. Time travel!

The maneuver actually takes two years, but it only feels like a couple seconds to everyone!

morngnstar
04-08-2016, 04:16 AM
It isn't practical to have tight maneuvers in space warfare.

For what reason? As you said, if you have a spacecraft going at 200 units, they might have a hard time changing heading, but there might be reasons why you have spacecraft moving at similar speeds to jet airplanes.

Also keep in mind that it's all relative in deep space, so you could have a space battle among fleets both hurtling toward a destination at .99c. From an the point of view of an external observer, they never change direction by more than a tiny fraction of a degree, but in the local reference frame they can be executing split S's and rolling scissors.


A few authors have described turns that took months to complete and using high energy missiles that were aimed at places where the opponent would have to be in a few months. If you predict location correctly and aim well, then you win; otherwise maybe not.

For their scenario maybe that made sense, but why couldn't you have close-in combat, where there would be no reason for weapons to take months to hit?

King Neptune
04-08-2016, 05:02 AM
For what reason? As you said, if you have a spacecraft going at 200 units, they might have a hard time changing heading, but there might be reasons why you have spacecraft moving at similar speeds to jet airplanes.

If you had the spacefighters moving at speeds comparable to jet airplanes, then they could maneuver similarly, but if they are moving at 0.5C, then it would take time to feed enough kinetic energy into machine to overcome the momentum, which is proportional to mass and velocity.


Also keep in mind that it's all relative in deep space, so you could have a space battle among fleets both hurtling toward a destination at .99c. From an the point of view of an external observer, they never change direction by more than a tiny fraction of a degree, but in the local reference frame they can be executing split S's and rolling scissors.

For their scenario maybe that made sense, but why couldn't you have close-in combat, where there would be no reason for weapons to take months to hit?

It would be possible to have close in combat, if they were all going in the same direction, but that would end whenever one side wanted to change direction, and then everything would change because of the delta V necessary.

You wouldn't catch me having close combat in space. I'd set a trap and then leave the area.

blacbird
04-08-2016, 05:06 AM
Also keep in mind that it's all relative in deep space,

It's all relative everywhere. That fella Mr. Einstein pretty well established that. You want to shoot a deer running past your pickup truck as you drive in the opposite direction, you gotta take that into account.

Especially if in your non-shootin' hand, you got a can of beer.

caw

morngnstar
04-08-2016, 05:24 AM
It would be possible to have close in combat, if they were all going in the same direction, but that would end whenever one side wanted to change direction, and then everything would change because of the delta V necessary.


How so? Assuming they have similar capabilities, if either side wants to maintain the close range, they can match the maneuver. If a defender with superior capabilities wants to escape, they may be able to, but that's no different than any combat situation, land, air, or sea.


You wouldn't catch me having close combat in space. I'd set a trap and then leave the area.

Assuming you have an undetectable trap. Otherwise your opponent just goes around it. Even if it's undetectable, unless it has a long range all the opponent has to do is fly a slightly erratic course and you'd be counting on luck. It all depends on the technology in your universe. I think for some universes, close combat might make sense.

onesecondglance
04-08-2016, 01:29 PM
To change the direction you're moving, you have to fire your engines. And that will result in a path that's a smooth curve.

Only if you decelerate in the direction you were heading at the same time.

If you are travelling forwards and you just apply thrust left, you will move diagonally forwards and left. If you want to "turn" left you have to stop moving forwards, either while you apply thrust or before. Not forgetting to rotate left as well, because otherwise you will be travelling in a different direction to the way you are facing...

kuwisdelu
04-08-2016, 02:18 PM
If you are travelling forwards and you just apply thrust left, you will move diagonally forwards and left.

But your trajectory will still be curved, because acceleration doesn't happen instantaneously. And unless you apply thrust "right" again at the end of the maneuver, well...


you will be travelling in a different direction to the way you are facing...

kuwisdelu
04-08-2016, 02:22 PM
This conversation is too difficult without graph paper.

onesecondglance
04-08-2016, 04:07 PM
Agreed.

King Neptune
04-08-2016, 04:45 PM
How so? Assuming they have similar capabilities, if either side wants to maintain the close range, they can match the maneuver. If a defender with superior capabilities wants to escape, they may be able to, but that's no different than any combat situation, land, air, or sea.

While there are similarities with atmospheric maneuvers, it would also be vastly different from operating in atmosphere, but it would depend on level of technology.


Assuming you have an undetectable trap. Otherwise your opponent just goes around it. Even if it's undetectable, unless it has a long range all the opponent has to do is fly a slightly erratic course and you'd be counting on luck. It all depends on the technology in your universe. I think for some universes, close combat might make sense.

Would it be a trap, if it were detectable?
My universe has time travel, and that changes everything.

kuwisdelu
04-08-2016, 07:44 PM
Trying to set a trap in the vastness of 3D space seems pretty useless to me.