I have a Star Wars model that list tech specs about the X-Wing fighter. Specifically it says an X-Wing can go “1050 km per hour in atmosphere”. I thought that didn’t sound very fast, and then I wondered if that would allow it to achieve escape velocity.
So, I looked up Earth’s escape velocity, which is apparently 11 km per second. I multiplied that by 660 secinds in an hour to get 39,600 km per hour.
Obviously there is a big gap between Earth’s escape velocity and the craft’s top speed. So now I am wondering…
is my math wrong?
if not, am I wrong about what escape velocity means? Do you really have achieve that speed to break free of Earth’s gravity?
is it the “in atmosphere” that offers a loophole? Could the craft fly to a really high altitude where the atmosphere thins, and then engage some different type of propulsion that allows it to achieve escape velocity?
I am not a Star Wars nut or anything, I just saw this pseudo factoid and wondered if the folks at Lucasfilm goofed or if my understanding of escape velocity was flawed.
You are entirely correct. 1050 km/h isn’t even supersonic. And yes, it is possible to get out of the atmosphere slowly and then accelerate to escape velocity. With current technologies this is a stupid way to get into space - you want to get there as quickly as possible, because the slower you go, the more fuel you need.
Actually, “escape velocity” is the energy needed to escape completely out of the earth’s gravitational well. To get out of the atmosphere and go into an orbit around the earth, you only need 7 km/s (orbital speed).
If I had to justify those specs, I’d say the X-wing isn’t designed to withstand the aerodynamic forces of supersonic atmospheric flight. Once in space it can fly as fast as you want.
You are entirely correct. 1050 km/h isn’t even supersonic. And yes, it is possible to get out of the atmosphere slowly and then accelerate to escape velocity. With current technologies this is a stupid way to get into space - you want to get there as quickly as possible, because the slower you go, the more fuel you need. (If that sounds counter-intuitive, remember that you need fuel just to hover. If you go infinitely slowly you need an infinite amount of fuel.)
Actually, “escape velocity” is the energy needed to escape completely out of the earth’s gravitational well. To get out of the atmosphere and go into an orbit around the earth, you only need 7 km/s (orbital speed), but that’s still much faster than 1050 km/h.
If I had to justify those specs, I’d say the X-wing isn’t designed to withstand the aerodynamic forces of supersonic atmospheric flight. Once in space it can fly as fast as you want.
I think your math is right
No, you dont have to achive that speed to leave the Earths gravity; an easy explanation of what scape velocity means is that it is the speed at which something has to be accelerated to leave the Earth, let´s suppose you´ve got a big bad gun that can fire a bullet at a speed of 11Km per second, if we conveniently dont consider the air resistance on the bullet then, it will scape Earths gravity if you fire it straight up. If the exit speed is less than that it will either drop to the ground or get into orbit.
But an X-Wings is supposed to have engines. as long as the engine thrust is greater than the ship´s weight the thing will keep going up, it doesn´t have to travel at 11Km per second.
The atmosphere would certainly slow down such an un-aerodynamic craft.
If the X-wing travels straight upwards at 1050 km, firing its engines all the way, it will soon reach the top of the atmosphere- then it can engage its main drive systems and fly about at arbitary speeds.
My problem with these craft, and particularly the Millennium Falcon, is that they seem to have incredible reserves of power in their hypertech engines, yet seem to have very small fuel tanks-
do you suppose they keep the fuel in hyperspace as well?
The Star Wars vessels are generally designed like winnebagos- lots of living room, minimal engine space.
One thing that occured to me about X-wings and most Star Wars ships in general is that they appear to already have a mechinism to negate a planets gravitational force. You will notice that they do not need to gain speed to “take off” they just sort of hover till they are pointing in the right direction and then …ZOOOOM. So in theory they could putter out of the atmosphere at 55mph if they were so inclined… correct?
I would like to point out that there is no reason those numbers are correct - everybody and their borther made up wild numbers because they sounded right for Star Wars. The only actual numbers you can trust are those from the movies directly or Curtis Saxton’s ICS. Anything you see in another model, technical manual, or book fall behind those.
Order of CANON for Star Wars (may be a little innacurate)
Movies -> Movie based-books -> Other books -> Comics/Video Games -> tech books and encyclopedias -> anythign else, including RPG’s and models.
Only the first two entries are really Canon, anything else is “speculative”. It doesn’t mean it didn’t happen, just don’t expect G. Lucas or any other author to respect it.
[note, with games, you can only trust the cutscenes; Kyle Katarn does not have a big sign that says the killed 50 bajillion stormtroopers]
So you can basically bet that the model makers probably just made it up on the spot.
For tooling around the atmosphere , that sounds about right, not sure what 1050 is , but if its something like 500 knots ,then cool.
Take a look at the X-wing , the a/c is not in a clean configuration when the s-foils are engaged and those four big guns sticking out, if the basic physics in the lucasverse is the same as our , then that causes a huge amount of drag.
I would imagine it could go a lot faster if the s-foils were closed, then it does look like it has a supersonic profile.
I think you’re right. IIRC, they use repulsorlift technology to generate lift close to a planet–those snowspeeders from Empire don’t fly like our planes do–they use repulsorlifts.
My guess is that the 1050 in atmosphere relates to the clearly non-aerodynamic ship’s safe speed inside the atmosphere (before it breaks up, steers horribly, etc.).
So if the 1050 number is correct, those things must be a bitch to do atmosphereic reentries. You’d probably have to fly backwards to keep the ship from entering too fast.
According to the books, repulsorlifts is what is used in atmosphere because the main engines are dangerous around humans and other beings. I’d guess repulsorlifts have the top speed issue (I mean, come on, with shields you’d be able to proceed at any speed, you’d just have to protect the craft from air with your particle shielding).
Also, X-wings apparently use some sort of fuel, possibly a fusion catalyst? IIRC fusion engines are mentioned in the X-wing series books.
I am glad that someone pointed out that X-wings have shielding, and repulsor-lift systems for use inside an atmosphere. The possibility of other equipment exists also. It is a craft out of a science fiction novel.
A common misconception, but there’s no such thing as “escape velocity”: There’s no direction associated with it, so it’s actually escape speed. Since we’re already ignoring air resistance anyway, it doesn’t matter what direction you point the cannon. So long as it’s not towards the Earth, at least, and even that will work if you’ve got a tunnel carved out. People just call it “escape velocity” because that sounds more “scientific”.
And as others have pointed out, escape speed really only matters if you’re launching from a cannon or the like, getting all of your speed at once. A craft with engines can, in principle, leave as slowly as it likes.
what the hell do the “S-Foils” need to be locked in “attack” or any other position? There’s no need for aerodynamics in space so what does it matter if the wings are in the ‘>+<’ or the ‘=+=’ position?
Even if the craft was surrounded by a shield, the shield would still provide aerodynamic drag.
Based on Lukes inelegent landing on Deghoba, I am willing to bet that the X-Wing is not an “all-weather” aircraft.
Hell, since it’s a space craft, what would weather have to do with it?
Of course it’s going to be somewhat robust. It is a military craft after all. (And the books explain why he crashed, because yoda wanted luke to land where he was…).
I’ve gathered from the books the whole Strike-foils thing has to do with hyperspace travel and not actual flight. In the “Wrath Squadran” book one of the pilots shoots even with the s-foils in flight mode.
And someone correct me if I’m wrong but doesn’t “escape velocity” only have to do with how fast you need to be moving to completely leave the gravity well of a planet without an engine? Like if I throw a rock at such speed, it will leave or acheve orbit?