RSS iconTwitter iconFacebook icon

The Trek BBS title image

The Trek BBS statistics

Threads: 140,245
Posts: 5,438,903
Members: 24,958
Currently online: 371
Newest member: greatmovies

TrekToday headlines

Cumberbatch In Wax
By: T'Bonz on Oct 24

Trek Screenwriter Washington D.C. Appearance
By: T'Bonz on Oct 23

Two Official Starships Collection Ships
By: T'Bonz on Oct 22

Pine In New Skit
By: T'Bonz on Oct 21

Stewart In Holiday Film
By: T'Bonz on Oct 21

The Red Shirt Diaries #8
By: T'Bonz on Oct 20

IDW Publishing January Comics
By: T'Bonz on Oct 20

Retro Review: Chrysalis
By: Michelle on Oct 18

The Next Generation Season Seven Blu-ray Details
By: T'Bonz on Oct 17

CBS Launches Streaming Service
By: T'Bonz on Oct 17


Welcome! The Trek BBS is the number one place to chat about Star Trek with like-minded fans. Please login to see our full range of forums as well as the ability to send and receive private messages, track your favourite topics and of course join in the discussions.

If you are a new visitor, join us for free. If you are an existing member please login below. Note: for members who joined under our old messageboard system, please login with your display name not your login name.


Go Back   The Trek BBS > Misc. Star Trek > Trek Tech

Trek Tech Pass me the quantum flux regulator, will you?

Reply
 
Thread Tools
Old November 25 2008, 12:04 AM   #76
Cary L. Brown
Rear Admiral
 
Location: Austin, Texas
Re: How do Starships stop?

Ronald Held wrote: View Post
Rick's answer seems to be the best recent one.
Well, the problem with Rick's answer is that the word "impulse" isn't just a made-up word. It's a real, technical, scientific word with a real, technical, scientific meaning. And that meaning is so clear, so specific, and so unambiguous that there's no room for redefinition.

If you want to say "sublight engines" the "field effect" idea is acceptable... but if you call them "impulse engines" then, BY DEFINITION, they are engines which produce propulsion through an impulse... that is, the application of a force over time.

If you say "impulse" you can simply substitute "thrust" and it means, for all practical purposes, the same thing. That's not "treknobabble," that's REALITY.

So "impulse engines" ... translation = "thrust engines"... have to be related to the generation of actual thrust.

I could live with his definition... but only if these things weren't being called "impulse engines."
Cary L. Brown is offline   Reply With Quote
Old November 25 2008, 02:15 AM   #77
Herkimer Jitty
Rear Admiral
 
Herkimer Jitty's Avatar
 
Location: Dayglow, New California Republic
Send a message via Windows Live Messenger to Herkimer Jitty
Re: How do Starships stop?

Cary L. Brown wrote: View Post
Ronald Held wrote: View Post
Rick's answer seems to be the best recent one.
Well, the problem with Rick's answer is that the word "impulse" isn't just a made-up word. It's a real, technical, scientific word with a real, technical, scientific meaning. And that meaning is so clear, so specific, and so unambiguous that there's no room for redefinition.

If you want to say "sublight engines" the "field effect" idea is acceptable... but if you call them "impulse engines" then, BY DEFINITION, they are engines which produce propulsion through an impulse... that is, the application of a force over time.

If you say "impulse" you can simply substitute "thrust" and it means, for all practical purposes, the same thing. That's not "treknobabble," that's REALITY.

So "impulse engines" ... translation = "thrust engines"... have to be related to the generation of actual thrust.

I could live with his definition... but only if these things weren't being called "impulse engines."
It could simply be a holdover term, like how the ships we're talking abotu aren't quite related to sea-fearing ships of old, and so on.
__________________
STAR TREK: 1964-1965½, 1966-1969, Jan. 21-23 1972, 1979-2001, 2003-2005, 2009-?
Herkimer Jitty is offline   Reply With Quote
Old November 25 2008, 02:54 AM   #78
Psion
Commodore
 
Psion's Avatar
 
Location: Lat: 40.1630936 Lon: -75.1183777
View Psion's Twitter Profile
Re: How do Starships stop?

Cary, is there any reason the thrust or force applied over time can't be non-newtonian in impulse engines? That is, produced without tossing something out of a combustion chamber?
__________________
Twinkies are back. I knew they couldn't stay away from me for long.
Psion is offline   Reply With Quote
Old November 25 2008, 03:18 AM   #79
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: How do Starships stop?

Psion wrote: View Post
Cary, is there any reason the thrust or force applied over time can't be non-newtonian in impulse engines? That is, produced without tossing something out of a combustion chamber?
Because thrust itself is a newtonian action and cannot be applied without an equal and opposite reaction. The subspace driver coils in impulse engines can be interpreted as adjusting the equation so that both the action and the reaction are of much greater magnitude to an outside observer as they are to anyone inside the ship (so in the ship's reference frame it accelerates at .3G while to an external observer it accelerates at a billion G) you still have a newtonian component of inertia behind it. The ship can only stop in one of two ways: by reversing thrust and stopping ("Reverse power!") or by cutting power to the driver coils ("Full stop!") or both (reverse thrust and stopping, cut driver coils in "Reverse power, full stop!") When you cut power to the driver coils, of course, the roaring .5C you just accumulated turns back into the crawling twenty meters per second you an everyone else in your ship experienced.
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old November 25 2008, 06:46 AM   #80
CuttingEdge100
Commodore
 
CuttingEdge100's Avatar
 
Re: How do Starships stop?

The God Thing

I don't know about "right", but it was certainly imaginative and based upon a very sound (for an aerospace engineer who specialized as a space vehicle dynamicist) understanding of quantum field theory and general relativity.
I didn't know he was an aerospace engineer...

No, the impulse engines are thrusting through the ship's center of mass, so any reverse thruster would have been placed on the leading edge of the saucer.
Actually it's not. The saucer when seperated has the impulse engines in the perfect spot. When connected the nozzles would have to be trimmed to prevent what would otherwise produce a strong nose down tendency.

When connected the reverse thrust location right under the torpedo tube would be quite good.

Of course, the fact that the ship has no reverse thruster on the saucer when a saucer seperation could happen is not a good design feature.
CuttingEdge100 is offline   Reply With Quote
Old November 25 2008, 07:09 AM   #81
GodThingFormerly
A Different Kind of Asshole
 
Location: An "American" in Friedrichshafen, Deutschland
Re: How do Starships stop?

CuttingEdge100 wrote: View Post
Actually it's not. The saucer when seperated has the impulse engines in the perfect spot. When connected the nozzles would have to be trimmed to prevent what would otherwise produce a strong nose down tendency.
You are assuming - with absolutely no justification - that the warp nacelles along with the segments of the pylons located above the impulse engine thrust line are substantially lighter than the secondary hull, interhull adapter and the pylon segments located below the impulse engine thrust line.

TGT
GodThingFormerly is offline   Reply With Quote
Old November 25 2008, 09:36 AM   #82
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: How do Starships stop?

CuttingEdge100 wrote: View Post
Actually it's not. The saucer when seperated has the impulse engines in the perfect spot. When connected the nozzles would have to be trimmed to prevent what would otherwise produce a strong nose down tendency.

When connected the reverse thrust location right under the torpedo tube would be quite good.

Of course, the fact that the ship has no reverse thruster on the saucer when a saucer seperation could happen is not a good design feature.
If you assume like I do that the ship channels its impulse exhaust through a subspace field anyway, the impulse engines can be anywhere on the ship you want them to be; the only thing you need is a space in which to bend the exhaust stream in a particular direction so its final vector goes through the center of mass.

This may or may not explain why Federation starships are built the way they are. After all, why would you have your gigantic warp nacelles and modules on the end of really long pylons when you could just build ALL of your ships like the Defiant, i.e. a dense flying brick of starship with nothing sticking out or exposed? The separation gives you more directions you can bend your impulse exhaust which in the end makes the ship more maneuverable at sublight speeds.
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old November 25 2008, 09:39 AM   #83
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: How do Starships stop?

The God Thing wrote: View Post
CuttingEdge100 wrote: View Post
Actually it's not. The saucer when seperated has the impulse engines in the perfect spot. When connected the nozzles would have to be trimmed to prevent what would otherwise produce a strong nose down tendency.
You are assuming - with absolutely no justification - that the warp nacelles along with the segments of the pylons located above the impulse engine thrust line are substantially lighter than the secondary hull, interhull adapter and the pylon segments located below the impulse engine thrust line.

TGT
From the way they're positioned, the warp nacelles and the upper pylon supports would have to account for something like 90% of the ship's total mass for the center of gravity to be that high. Are we looking at a 70,000 ton ship with a pair of 500,000 ton warp nacelles attached to it? Each seperate warp coil would have to weigh as much as the Titanic.
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old November 25 2008, 10:21 AM   #84
Timo
Admiral
 
Re: How do Starships stop?

Well, the problem with Rick's answer is that the word "impulse" isn't just a made-up word. It's a real, technical, scientific word with a real, technical, scientific meaning. And that meaning is so clear, so specific, and so unambiguous that there's no room for redefinition.
But that sounds like so much nonsense. Booting of computers has nothing to do with footwear, the gas in automobile gas tanks is not gaseous (and indeed nonsense terminology like "liquid gas" is in regular use), and a fission bomb or even a napalm bomb is considered a kinetic weapon. Against this background, it would be absurd to insist that the iconic drive system of starships would have to hold on to some specific meaning of the word being used as its name.

From the way they're positioned, the warp nacelles and the upper pylon supports would have to account for something like 90% of the ship's total mass for the center of gravity to be that high. Are we looking at a 70,000 ton ship with a pair of 500,000 ton warp nacelles attached to it? Each seperate warp coil would have to weigh as much as the Titanic.
Which in fact sounds rather attractive. That way, Scotty's "nearly a million gross tons" would make perfect sense for a ship whose hull weighs in at 180,000 tons or so.

Of course, this solves absolutely nothing as regards the subject of this thread, because the impulse engines of the Reliant would then in turn be located in a Newtonially unworkable location.

Timo Saloniemi
Timo is offline   Reply With Quote
Old November 25 2008, 11:06 AM   #85
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: How do Starships stop?

Timo wrote: View Post
Well, the problem with Rick's answer is that the word "impulse" isn't just a made-up word. It's a real, technical, scientific word with a real, technical, scientific meaning. And that meaning is so clear, so specific, and so unambiguous that there's no room for redefinition.
But that sounds like so much nonsense. Booting of computers has nothing to do with footwear, the gas in automobile gas tanks is not gaseous (and indeed nonsense terminology like "liquid gas" is in regular use), and a fission bomb or even a napalm bomb is considered a kinetic weapon. Against this background, it would be absurd to insist that the iconic drive system of starships would have to hold on to some specific meaning of the word being used as its name.
"Booting" and "gas" are both shorthand terms that are shortened from longer or related terms. "booting" in computers comes from the term "bootstrapping," which means using a simple system to activate a more complex system. "Gas" is a shortening of "gasoline" which specifically refers to a petroleum product.

"Impulse" is already a term used in aerospace engineering and spacecraft propulsion in the same way "bootstrapping" already had connotations of someone or something performing a complicated process through simple means without external help.

Timo wrote: View Post
From the way they're positioned, the warp nacelles and the upper pylon supports would have to account for something like 90% of the ship's total mass for the center of gravity to be that high. Are we looking at a 70,000 ton ship with a pair of 500,000 ton warp nacelles attached to it? Each seperate warp coil would have to weigh as much as the Titanic.
Which in fact sounds rather attractive. That way, Scotty's "nearly a million gross tons" would make perfect sense for a ship whose hull weighs in at 180,000 tons or so.
And then you'd have to postulate verterium cortenide or whatever Enterprise is using as being some kind of ultra-dense material such that a chunk of it the size of a football would weigh as much as a compact car. I don't really disagree with this in principle, just that the logistics of working with material this dense and this heavy aren't well represented in the Trekiverse (and didn't we see some shuttlecraft lifting warp coils out of Voyager's warp nacelle once?)

Timo wrote: View Post
Of course, this solves absolutely nothing as regards the subject of this thread, because the impulse engines of the Reliant would then in turn be located in a Newtonially unworkable location.
Same case for the E-D, whose impulse engine is slightly below the nacelles, or NX-01 whose nacelles are well above centerline, or runabouts and shuttlecraft whose engines are nowhere near in line with the nacelles (given the same material, a single warp coil would weigh more than the entire rest of the shuttlecraft). Any way you play it, you're going to need something to curve the exhaust plume so it thrusts through the ship's center of mass.
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old November 25 2008, 11:24 AM   #86
Timo
Admiral
 
Re: How do Starships stop?

"Booting" and "gas" are both shorthand terms that are shortened from longer or related terms. "booting" in computers comes from the term "bootstrapping," which means using a simple system to activate a more complex system. "Gas" is a shortening of "gasoline" which specifically refers to a petroleum product.
So "impulse" could perfectly well be a similar shortening. Just because it also remains in use in a different meaning is irrelevant, as "boot" and "gas" also do.

I don't really disagree with this in principle, just that the logistics of working with material this dense and this heavy aren't well represented in the Trekiverse (and didn't we see some shuttlecraft lifting warp coils out of Voyager's warp nacelle once?)
Well, warp coils are the most magical part of starship construction anyway, so maximizing the magic doesn't sound like a bad idea.

And shuttles can travel at warp two or go from planet to planet in a matter of hours or minutes. Lifting a chunk of neutronium-unobtainium doesn't sound like asking too much of those engines... (That was in VOY "Nightingale", FWIW.)

Any way you play it, you're going to need something to curve the exhaust plume so it thrusts through the ship's center of mass.
If it even needs to do that. The exhaust plume of a Chevrolet Corvette does not.

There are starships with impulse engines that seem to blast right into their own pylon structures, such as the ENT Intrepid or the Steamrunner. Perhaps there is no jet of exhaust associated with an impulse nozzle, just a warm puff of waste matter being vented in a random direction every now and then. The drive could still combine "field propulsion" and pseudo-rocketry, but the rocket exhaust would be generated in some manner unrelated to the nozzles. Perhaps there's a giant virtual "thrust chamber" being generated out of forcefields, well aft of the ship, or forward if need be - kilometers wide, of variable shape, the works...

Timo Saloniemi
Timo is offline   Reply With Quote
Old November 25 2008, 11:43 AM   #87
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: How do Starships stop?

Timo wrote: View Post
"Booting" and "gas" are both shorthand terms that are shortened from longer or related terms. "booting" in computers comes from the term "bootstrapping," which means using a simple system to activate a more complex system. "Gas" is a shortening of "gasoline" which specifically refers to a petroleum product.
So "impulse" could perfectly well be a similar shortening. Just because it also remains in use in a different meaning is irrelevant, as "boot" and "gas" also do.
No, because "bootstrapping" means roughly the same thing in computer science as it does in vernacular. There is no similar term in computer science or mathematics that has a different meaning. Similar to the term "gasoline" which has been in use since at least the 19th century and has no similar term with which it may be confused (in fact, even "natural gas" as a fuel source is generally referred to as "CNG" for precisely this reason).

"Impulse" could be an acronym, as in "IM-Pulse" or something, but it's too late to redact that since so far it's always been written as the conventional word and, on a few occasions, has actually been USED in the conventional newtonian sense.

Timo wrote: View Post
Any way you play it, you're going to need something to curve the exhaust plume so it thrusts through the ship's center of mass.
If it even needs to do that. The exhaust plume of a Chevrolet Corvette does not.
The exhaust plume of a Corvette cannot be used to push the car forward if you put the gearshift in neutral. Impulse engines can.

Timo wrote: View Post
There are starships with impulse engines that seem to blast right into their own pylon structures, such as the ENT Intrepid or the Steamrunner.
Which would be a bad design even if impulse engines merely vented exhaust non-propulsively. Not so if the ship has a system inherent in the engine to control what path the exhaust plume takes as it leaves the nozzle.

Timo wrote: View Post
Perhaps there is no jet of exhaust associated with an impulse nozzle, just a warm puff of waste matter being vented in a random direction every now and then. The drive could still combine "field propulsion" and pseudo-rocketry, but the rocket exhaust would be generated in some manner unrelated to the nozzles. Perhaps there's a giant virtual "thrust chamber" being generated out of forcefields, well aft of the ship, or forward if need be - kilometers wide, of variable shape, the works...
Perhaps the impulse engine propels the ship by rapidly breeding tribbles and then beaming them into deep space where their shrill cries for help cause an impulsive reaction in the ship's improbability field?

Or maybe impulse engines work pretty much the way they're implied to work, as technobabble rocket engines that use "driver coils" to overcome the inevitable restrictions of Jon's Law?
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old November 25 2008, 11:51 AM   #88
Timo
Admiral
 
Re: How do Starships stop?

The exhaust plume of a Corvette cannot be used to push the car forward if you put the gearshift in neutral. Impulse engines can.
According to whom?

Quite to the contrary, it appears that a starship at full stop (say, relative to an adversary ship floating off her bow) can still perfectly well have her impulse engine glowing just as madly as when at "full impulse".

Or maybe impulse engines work pretty much the way they're implied to work, as technobabble rocket engines that use "driver coils" to overcome the inevitable restrictions of Jon's Law?
It might help if the implication were explicated at some point. We have a conspicuous lack of references to rocketlike behavior of impulse engines in onscreen material. Instead, impulse typically seems to behave like a maritime propeller system, free of propellant even if needing fuel, and governed by the need to maintain power for steady speed.

The idea of there being a rocket component to impulse engines is something that can be made to work with suitable effort. Such a component is not an onscreen necessity, though.

Timo Saloniemi
Timo is offline   Reply With Quote
Old November 25 2008, 12:30 PM   #89
Crazy Eddie
Rear Admiral
 
Crazy Eddie's Avatar
 
Location: I'm in your ___, ___ing your ___
Re: How do Starships stop?

Timo wrote: View Post
The exhaust plume of a Corvette cannot be used to push the car forward if you put the gearshift in neutral. Impulse engines can.
According to whom?
TNG "Booby Trap" the impulse engines were used--apparently without their driver coils--to accelerate the Enterprise to inertial flight at over a hundred meters per second. Apparently the subspace/warp fields used for propulsion were what the aceton assimilators were reacting to in order to hold the ship in place, so using the impulse engines without the field-effect boost reduced them to old-fashion rocket engines.

From the same episode you find that the "glow" continues in the engine even after it is shut down, as it does on the saucer in "Best of Both Worlds" despite the fact that the impulse engines are said to be damaged. Considering the impulse engines are powered by fusion reactors and double as a power source for the ship, I'd be a little alarmed if they STOPPED, glowing even when the ship was at rest.


Timo wrote: View Post
Or maybe impulse engines work pretty much the way they're implied to work, as technobabble rocket engines that use "driver coils" to overcome the inevitable restrictions of Jon's Law?
It might help if the implication were explicated at some point.
See above. And also check out Scotty's line in "Relics" where he mentions that the ion trail from Enterprise' engines is indicative of "an impulse engine at full reverse." This is clearly technobabble, but the implication here is that impulse exhaust behaves differently depending on what direction you're trying to go, something that could ONLY be explained by a propulsive effect by the exhaust.

Timo wrote: View Post
The idea of there being a rocket component to impulse engines is something that can be made to work with suitable effort. Such a component is not an onscreen necessity, though.
One removes that component only with copious amounts of handwavium and fanciful thinking which in this case is not warranted. One might as well pick up a coke bottle and say "This could be described as a coke bottle with a suitable effort, but it could just as easily be a flux capacitor from the 35th century."
__________________
The Complete Illustrated Guide to Starfleet - Online Now!
Crazy Eddie is offline   Reply With Quote
Old November 25 2008, 02:41 PM   #90
Santaman
Rear Admiral
 
Santaman's Avatar
 
Location: A little while in the past.
Re: How do Starships stop?

And also check out Scotty's line in "Relics" where he mentions that the ion trail from Enterprise' engines is indicative of "an impulse engine at full reverse." This is clearly technobabble, but the implication here is that impulse exhaust behaves differently depending on what direction you're trying to go, something that could ONLY be explained by a propulsive effect by the exhaust.
No, there are more ways to explain it actually, the exhaust coming from the fusion engines will form a plume in a certain way and shape, if you're on full impulse forward and you're dragged ass first towards the dyson sphere then your ship will pass through the gas its belching out making quite a nice pattern which a computer of any kind in the 23th/24th century can distinguish, this still doesn't have to mean that the exhaust of the fusion reactors has anything to do with the propulsion method of the impulse engines themselves.
__________________
"Sword is personal, brings slicing to a man, you getta that personal feedback, nuclear weapons?.. Meh, goes off big bang and you don't get any feeling.."
Santaman is online now   Reply With Quote
Reply

Bookmarks

Tags
technobabble, warp drive

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT +1. The time now is 08:15 AM.

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
FireFox 2+ or Internet Explorer 7+ highly recommended.