Acceleration of SW-vessels

FTeik · Post by **FTeik** » 2006-06-14 06:11pm

I was recently looking over Wookiepedia's entries about fighters in SW and noticed, that they had the acceleration given in Gs among the stats of some of the fighters and capital ships.

Until then i was only aware of the acceleration-values given by the ICS-books.

What i want to know is, if there are other values for acceleration given in official literature. I'm not asking for guesses based on that or that source, but a clear given value.

Thanks.

Jim Raynor · Post by **Jim Raynor** » 2006-06-14 06:22pm

I believe every ship in The New Essential Guide to Vehicles and Vessels had a Saxton-like acceleration in the thousands of Gs. Unfortunately, it still had WEG-like atmospheric speeds of about a 1,000 kph.

That's the only non-ICS book with acceleration values that I'm aware of.

Vehrec · Post by **Vehrec** » 2006-06-14 09:27pm

To be honest, most of the time you have NO good reason to go that fast in atmosphere. Supersonic fighter duels in atmosphere wouldn't cut it with the line of sight weapons used by most fighters. Also, the un-areodynamic shapes of most starfighters would limit them severly in atmosphere, not to mention the sheer danger represented by a ships engines close to the surface of a planet. The reason Lusankya had that massive repulsorlift bed wasn't to ensure that it could escape a gravity well, it was so thousands of square miles of Coruscant wouldn't be turned into a smoldering radioactive pile. The effectiveness of a drive as a method of propulsion is directly proportional to its effectiveness as a weapon remember.
And I must now go get the NEGtVaV.

RThurmont · Post by **RThurmont** » 2006-06-14 09:37pm

One of the main problems of aircraft operating at high speeds within the atmosphere is friction heating up the outer surfaces of the vehicle, causing them to loose their strength (and eventually fail). In the case of SW starfighters, one would assume that they're made out of a sufficiently strong, heat-resistant material so that that would not be as much of an issue, unless they were travelling at insanely high speeds. Also, while the angular design of ships like the Y wing would result in considerable added drag, one would also naturally assume that the engines on SW fighters are more than powerful enough to compensate. Engines doing damage to cities is a more compelling argument for atmospheric speed limits.

Batman · Post by **Batman** » 2006-06-14 09:48pm

Why, pray tell, is atmospheric friction a problem for a civilisation that has particle shields?
I agree that going fractional C in-atmosphere is something that generally ought to be avoided due to environmental impacts, but how does that prevent them going hypersonic at height?

Fingolfin_Noldor · Post by **Fingolfin_Noldor** » 2006-06-14 10:46pm

I would point out that travelling at incredibly fast speeds in the atmosphere probably results in a huge sonic boom which might be enough to flatten a small town or something.

PainRack · Post by **PainRack** » 2006-06-14 10:59pm

Batman wrote:Why, pray tell, is atmospheric friction a problem for a civilisation that has particle shields?
I agree that going fractional C in-atmosphere is something that generally ought to be avoided due to environmental impacts, but how does that prevent them going hypersonic at height?

SW version of the EPA.

Cykeisme · Post by **Cykeisme** » 2006-06-14 11:15pm

It might not be an issue of how much thrust the engines can generate to overcome atmospheric drag, but rather the stability of flight.
Even travelling in a perfectly straight line at hypersonic speeds would be difficult for a non-aerodynamic fighter, because their irregular shapes would undoubtedly put torque on the ship around its center of mass. Furthermore, this torque would be irregular due to the wind and uneven atmospheric density (which is an issue when you're travelling through a kilometer or so of atmosphere every second).
Starfighters simply aren't designed for atmospheric combat, but they still do pretty well at it.

Anyway, I'd take the atmospheric speeds with a pinch of salt, since they don't take into account atmospheric density at all. Even on a given planet, that would vary with altitude. The only logical meaning it may have is that it's given for sea level on a standard planet (Coruscant?).

Also, most of the heat from re-entry (or simply flying at high speeds) isn't actually generated by friction, but because of the compression of the atmospheric gas ahead of the path of a moving vehicle. Reducing its volume increases its temperature.. and this is being done continously for a long swath of atmosphere.

RThurmont · Post by **RThurmont** » 2006-06-14 11:17pm

I agree that going fractional C in-atmosphere is something that generally ought to be avoided due to environmental impacts, but how does that prevent them going hypersonic at height?

Apparently "gravity wells" projected by planets, stars, etc, interfere to some extent with SW hyperdrives...the secret of the Interdictor-class cruisers.

Vehrec · Post by **Vehrec** » 2006-06-14 11:19pm

Cykeisme wrote: Even on a given planet, that would vary with altitude. The only logical meaning it may have is that it's given for sea level on a standard planet (Coruscant?).

But there aren't seas per say on Coruscant. Haven't been for millenia, although they are still there, under all the buildings.

You know, considering how much it got hammered in the EU, Coruscant itself is a good indicator of how advanced the GFFA is in terms of industry. They can rebuild (part of) a city that covers an entire planet at least twice in a 30 year period.

Connor MacLeod · Post by **Connor MacLeod** » 2006-06-14 11:23pm

Fingolfin_Noldor wrote:I would point out that travelling at incredibly fast speeds in the atmosphere probably results in a huge sonic boom which might be enough to flatten a small town or something.

at hypersonic speeds you're probably going to get more than just sonic booms - you'll get superheated air/fireballs in the wake for most vessels.

In practice they probably either do it very rarely (emergencies) when they're low level to the ground or they go up to very high altitudes to do it (where the dangers woudl be lessened.)

FTeik · Post by **FTeik** » 2006-06-15 09:05am

Alright, but WHAT values for linear acceleration are given? I can hardly comment on them, if i don't know them. And no, i don't have the EGVV or the NEGVV.

Duckie · Post by **Duckie** » 2006-06-15 09:34am

FTeik wrote:Alright, but WHAT values for linear acceleration are given? I can hardly comment on them, if i don't know them. And no, i don't have the EGVV or the NEGVV.

I remember the Star Wars vs. Star Trek in 5 minutes page had like low Thousands for Acceleration in Gs (!!!).

Here it is:
Acclamator: 3,500Gs
Slave-1: 2,500Gs

Interestingly, the Acclamator as a full-sized warship is faster than the Slave-1, a freighter-sized combat modified ship (basically a gigantic fighter thingie like the Falcon I guess). That's probably an anomalie.

Fingolfin_Noldor · Post by **Fingolfin_Noldor** » 2006-06-15 09:52am

Perhaps because the Acclamator is primarily a troop carrier and landing craft, the fast acceleration allows for rapid orbital insertion and landing?

Turin · Post by **Turin** » 2006-06-15 09:53am

MRDOD wrote:Interestingly, the Acclamator as a full-sized warship is faster than the Slave-1, a freighter-sized combat modified ship (basically a gigantic fighter thingie like the Falcon I guess). That's probably an anomalie.

Why would it be? A larger vessel can have a much larger reactor. In ESB an ISD can keep up with the Millenium Falcon in sublight.

Duckie · Post by **Duckie** » 2006-06-15 10:04am

Turin wrote:
MRDOD wrote:Interestingly, the Acclamator as a full-sized warship is faster than the Slave-1, a freighter-sized combat modified ship (basically a gigantic fighter thingie like the Falcon I guess). That's probably an anomalie.
Why would it be? A larger vessel can have a much larger reactor. In ESB an ISD can keep up with the Millenium Falcon in sublight.

That really is a good point. I don't know why I figured it was unusual, except that smaller ships usually = faster in my mind what with fighters and all.

Stark · Post by **Stark** » 2006-06-15 10:08am

It says something about the scaling of reactor outputs that huge, mile-ish ships can be built to be faster than 40m courier ships. However, this doesn't suggest that this is always true, as both the ISD and the Acclamator had speed as a major design goal, whereas things like the original YT wouldn't, as it'd spend most of it's time in hyperdrive. High sublight speeds is something more useful to warships than civilian craft, I think.

FTeik · Post by **FTeik** » 2006-06-15 11:42am

The dagger-shape also allows to devote more space to thrusters than other ship-shapes seen in SW.

And, as i already said in the OP, i know the numbers given by the ICS-books. I want to know, if there are others published and what they are (once this question is answered, the next point would be decide how reliable those numbers would be). My next short-story will deal a lot with TIE-fighters and i want things to be as accurate as possible, so i need those stats as a starting-point.

Feil · Post by **Feil** » 2006-06-15 11:52am

A pretty good selection of information could be done with educated guesses and calculations. Using 3500 G's as a baseline for warship acceleration, we can assume that bombers would be faster by an amount significant with regards to combat distances, and that interceptors and fighters would be significantly faster. Bombers must be able to outrun their prey and their mother ship; interceptors and fighters must be able to force bombers to engage for several seconds at low visiual range.

Jim Raynor · Post by **Jim Raynor** » 2006-06-15 12:51pm

Vehrec wrote:To be honest, most of the time you have NO good reason to go that fast in atmosphere. Supersonic fighter duels in atmosphere wouldn't cut it with the line of sight weapons used by most fighters. Also, the un-areodynamic shapes of most starfighters would limit them severly in atmosphere, not to mention the sheer danger represented by a ships engines close to the surface of a planet. The reason Lusankya had that massive repulsorlift bed wasn't to ensure that it could escape a gravity well, it was so thousands of square miles of Coruscant wouldn't be turned into a smoldering radioactive pile. The effectiveness of a drive as a method of propulsion is directly proportional to its effectiveness as a weapon remember.
And I must now go get the NEGtVaV.

But slower than Mach 1? Yeah right. Of course you can't go as fast in an atmosphere as you can in space, but X-wings with a top atmospheric speed of 1,000 kph is just ridiculous.

Aquatain · Post by **Aquatain** » 2006-06-15 07:35pm

Jim Raynor wrote:
Vehrec wrote:To be honest, most of the time you have NO good reason to go that fast in atmosphere. Supersonic fighter duels in atmosphere wouldn't cut it with the line of sight weapons used by most fighters. Also, the un-areodynamic shapes of most starfighters would limit them severly in atmosphere, not to mention the sheer danger represented by a ships engines close to the surface of a planet. The reason Lusankya had that massive repulsorlift bed wasn't to ensure that it could escape a gravity well, it was so thousands of square miles of Coruscant wouldn't be turned into a smoldering radioactive pile. The effectiveness of a drive as a method of propulsion is directly proportional to its effectiveness as a weapon remember.
And I must now go get the NEGtVaV.
But slower than Mach 1? Yeah right. Of course you can't go as fast in an atmosphere as you can in space, but X-wings with a top atmospheric speed of 1,000 kph is just ridiculous.

X-wings are Space supiriority Fighters.. they are made to fight in space, the fact that they can land on planets and fly in atmosphres are a bonus.

Jim Raynor · Post by **Jim Raynor** » 2006-06-15 08:31pm

We see civilian transports in the movies quickly breaking free of the atmosphere. And X-wings are from a family of fighters that have included a number of capable atmospheric craft. 1,000 kph is pure crap. Can you imagine an X-wing slooooowly flying through the air while 1940s era MiG-15s outrace them? Absurd.

Aquatain · Post by **Aquatain** » 2006-06-15 08:53pm

Jim Raynor wrote:We see civilian transports in the movies quickly breaking free of the atmosphere. And X-wings are from a family of fighters that have included a number of capable atmospheric craft. 1,000 kph is pure crap. Can you imagine an X-wing slooooowly flying through the air while 1940s era MiG-15s outrace them? Absurd.

A Akula submarine will do 35 knots submerged, but only 20 knots on the surface - a 1850th Tea Clipper sailing vessel could overtake it on the surface.Absurd?

Duckie · Post by **Duckie** » 2006-06-15 08:57pm

In the Clone Wars Cartoons I'm pretty sure it shows Republic Gunships either going to hyperspace in an atmosphere (pretty strange) or they accelerating fast enough to look like that. Perhaps in the emergency of a battle we're witnessing Space-level acceleration at that.

However I don't remember it fully, I could be imagining that.

Jim Raynor · Post by **Jim Raynor** » 2006-06-15 09:45pm

Aquatain wrote:
Jim Raynor wrote:We see civilian transports in the movies quickly breaking free of the atmosphere. And X-wings are from a family of fighters that have included a number of capable atmospheric craft. 1,000 kph is pure crap. Can you imagine an X-wing slooooowly flying through the air while 1940s era MiG-15s outrace them? Absurd.
A Akula submarine will do 35 knots submerged, but only 20 knots on the surface - a 1850th Tea Clipper sailing vessel could overtake it on the surface.Absurd?

Why are you even arguing for the retarded 1,000 kph?

The tech gap (not to mention the gaps in speed between air/spacecraft and naval ships) is far larger. It contradicts movie visuals. It contradicts the much more sensible starfighter speeds Saxton wrote for his ICS books.

If we assume that the WEG speed is correct, then a SW naval commander better damn hope he never has to send his starfighters to bomb the enemy on the ground (something they do quite often), because they'll be crawling around at pathetic subsonic speeds.