Wednesday, 23 February 2005 10:04 PM -0800
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I recommend reading the following documents by Jason Hinson:
Both of these are posted frequently to rec.arts.startrek.tech, and they can also be found at http://www.ee.umanitoba.ca/~djc/startrek/.
This FAQ does not discuss warp speeds. See the Warp Velocities FAQ for discussions of the various warp speed scales and formulas to calculate speeds given a warp factor.
NOTE: There are two distinct problems to be solved when describing any FTL drive:
Both must be addressed to form a believable FTL system.
"Warp works by <insert idea here>!"
Some favorites include:
All of these attempt to get around the first problem, but ignore the second. And none of these match the evidence seen on screen and in the Tech Manual, which is that the FTL effect is created by powerful, nested subspace (a.k.a. warp) fields that push off each other to generate FTL speeds.
Further, without any additional effects, each of these can lead to a violation of causality, meaning every time you go into warp you time travel, from a certain frame of reference. This is addressed in great detail in Jason Hinson's "Relativity and FTL" FAQ.
Ships in warp interact with things in normal space, one of the reasons for the navigational deflector. Things in warp require a subspace field to enter and stay in warp, and it takes an enormous amount of power to generate this. When the subspace field decays, a ship drops out of warp returning to some STL velocity.
* The point has been made that by constructing a space with a hyperbolic geometry between the source and destination of two points, you can get away with FTL travel without the nasty causality violation effects pointed out by Jason's FAQ. However, this involves making changes to space-time along your entire flight path before you travel, and it does not appear possible to construct this path faster than c, so you'd have to set up a travel network beforehand. This obviously isn't what is used in Star Trek.
** A subspace field does reduce the inertial mass of an object within it, i.e. it appears lighter. But it does not lower the mass to zero, nor on its own would this effect allow FTL travel, as massless particles in our universe are still restricted to light speed. It turns out that this effect isn't even considered for warp travel, although it is used for impulse engines - less mass to push around.
"Well, so how *does* warp work?"
A powerful, asymmetric subspace field is established around the ship by the warp nacelles. The field is composed of nested layers, each pushing against the one beyond it. This drives the ship forward, at a super-luminal velocity.
The nacelles are powered by a tuned plasma stream from the warp core Matter/Antimatter Reactor (M/AMR). Injectors feed the plasma into warp field coil segments at specific times, causing pulses to run the length of the nacelle, front to back. This peristaltic flow causes the push of the nested warp fields, and moves the ship forward.
The warp field wraps around the ship in a two-lobed bubble, with the locus at Main Engineering (by design). The shape of the ship determines the efficiency of the field, and this explains why the Enterprise has such a sleek design.
Meanwhile, the subspace field reduces the inertial mass of the ship, aiding in maneuvering. In fact, a small subspace field is kept around the ship at Impulse speeds, so the Impulse drives have less mass to push around. However, this is only a side effect and is NOT the mechanism used to allow FTL travel.
"But, but... that's just what it does! How does it work!!!"
Alas, there is no canonical answer. The "Relativity and FTL" FAQ offers a possibility, that the subspace field forces the ship to take on the reference frame of subspace itself, which is a special reference frame, circumventing the limits of Special Relativity.
Unfortunately, this still isn't an explanation of how it works. The Tech Manual offers that each of the nested fields couple and decouple from each other at velocities near (but less than) c. It could be that the interaction of these fields, combined with the special frame subspace provides, causes the ship as a whole to travel at FTL speeds.
If two nested fields have their outer edges "locked" into the special frame, while the inner edges travel at near-c relative to one another, this might cause the FTL effect, as an artifact of the special frame trick. This has the added support of being almost exactly what the Tech Manual describes, but it doesn't mention the special frame.
Since this makes for boring drama, it's unlikely we'll ever "really know" how warp works in Star Trek.
"So what stops the ship from accelerating and getting faster and faster?"
Warp travel is non-Newtonian. Without a constant influx of energy, the subspace field will decay, and the ship will drop out of warp. In other words, you *must* continue to provide energy to maintain your warp velocity.
Anything which travels at FTL speeds must use a warp field (or some other technology) to keep moving at those speeds.
"What about 'continuum drag' ?"
This was an idea proposed in the forgotten past to explain the above problem. To me, however, it seem that there is no need for such a force, since we are not dealing with Newtonian action/reaction drives, or force/acceleration systems.
"So how'd the Saucer travel at warp speeds (in "Encounter at Farpoint" [TNG]) ?"
The Tech Manual states that the subspace field generators coupled to the Impulse drive can be used to maintain a decaying subspace field for brief periods of time. The decay is inevitable, but it can be drawn out, to allow the saucer section to get out of danger.
By field-saturating the nacelles (according to "Force of Nature" [TNG]), after a 6 second burst of maximum warp the Enterprise can "coast" at warp for 2 minutes 8 seconds before dropping out of warp. This is a form of "warp without warp drive", although the effect does not last very long.
This is similar to how photon torpedoes can be used at warp speeds. They have small "warp sustainer" engines that allow them to cruise at their launch velocity (if launched while in warp) for brief periods.
"This Warp 5 speed limit - what's up with that?"
In "Force of Nature" [TNG] it is discovered that within the Hekaras Corridor, a region of space where warp travel is hindered except for a narrow path, the intense use of warp drives in an already sensitive area can, over time, cause subspace rifts to form, where subspace manifests itself in real space on a macroscopic scale. To alleviate the problem the Federation imposed a speed limit of Warp 5 on all starships which remained in place until at least the following year. In "The Pegasus" [TNG] Admiral Pressman gives Picard permission to travel faster than Warp 5 for the duration of the mission. In "Eye of the Beholder" [TNG] Picard is given permission to exceed the speed limit to delivery needed medical supplies.
There is a general assumption is that engine modifications later solved the problem; there has been no further mention of the speed limit. This is fueled by rumors that Voyager's back story includes an updated warp core that is "environmentally friendly."
"What is subspace?"
According to the Encyclopedia, it is a continuum with different laws than our own. That doesn't help much, considering you can makes fields of it in our universe.
The best explanation I can come up with is that subspace is the "substrate" within which our universe exists. A subspace field is either a forced or natural intrusion of this domain into our own space, altering the behavior of things within our space-time. The "subspace barrier" is the albeit flimsy dividing line between the two continuums.
Many things support this: in "Schisms" [TNG] creatures exist within a tertiary subspace manifold, a manifold being a term used to describe the form our own universe takes when viewed from a higher (theoretical) dimension. This is also called a deeper level of subspace; another universe which is connected to ours by subspace. In "Remember Me" [TNG] an entirely new universe was "spawned off" by a static warp bubble, and it was only accessible through subspace. The proto-universe in "Playing God" [DS9] was an intense subspace manifestation as well.
Protrusions of subspace, such as in "Force of Nature" [TNG], "Vortex" [DS9], or the shockwave in ST6 do nasty things to our space-time. But subspace is also everywhere: sensors can detect subspace distortions caused by normal objects ("Descent" [TNG] ), communications work through subspace, and you can create subspace fields.
Whenever our space-time is distorted or torn, or large amounts of energy released (explosions) there are subspace effects; wormholes and Transwarp Conduits are good examples where subspace plays a part in the effect, and the presumably material-based explosion of Praxis in Star Trek VI generated the subspace shockwave. Also, in "Caretaker" [VOY] Captain Janeway mentioned that the warp core of a starship would leave behind a resonance trace signature even if the ship was destroyed - this indicates that the constant matter/antimatter reaction in a starship's warp core generates subspace fields as well.
Subspace fields (the kind that move starships around) are intentional manifestations of subspace in our space-time, caused by the controlled release of energy in a warp field coil. These fields have many effects, often depending on the intensity.
You can think of subspace as being the "medium" in which our space-time exists. The nearest parts (nearest being measured by the energy it takes to access them) are tightly coupled to our own universe, and can be thought of as being mapped to our space-time. This is what sensors generally read, and what the subspace fields of warp drive are interacting with. Slightly deeper parts can connect points in our universe to others. Wormholes and Transwarp Conduits are this sort of thing. Deeper still are the "untamed wilds" seen in "Force of Nature" [TNG]. And even further down are entirely separate universes, all held together by subspace.
Subspace is not in an alternate reality, or "place", or space-time where things go - or at least, they don't go in the world of Star Trek. It is not entered by a starship at warp. A ship creates a subspace field which acts like another universe very tightly coupled to our own. If I was inside such a field and you were outside, we could conduct a conversation, shake hands, etc. But when the field is powerful enough (1000 millicochranes or more) and asymmetric, it is propulsive. Nested, decoupling fields magnify the effect considerably. But the ship still interacts with everything in our universe, and vice versa, as the level of subspace in which the field exists is so tightly coupled to our own that it appears no "fancier" than, say, a magnetic field, if you're looking closely at it.
The weakest subspace fields do appear very similar to traditional fields, like magnetic fields. They have associated particles (see below), can be bound to objects ("Phantasms" [TNG]), can be used for transmissions (subspace radio), and generally unremarkable on their own other than as residue from more powerful effects.
To keep Jason Hinson and Special Relativity happy, subspace doesn't need to follow the rules of relativity. Subspace might have a unique reference frame, and everything enclosed in a subspace field has the reference frame of subspace.
"What are Tetryons and Verterons?"
Subatomic particles mentioned in "Force of Nature" [TNG], and a number of other episodes. These seem to be some of the particles associated with subspace fields, just as photons are particles associated with electromagnetic fields.
A verteron mine is used to disable the Flemming, a Ferengi ship, and the Enterprise in "Force of Nature". Verterons somehow manage to disable all devices which use subspace. Simplest explanation - they inhibit interactions with subspace, causing massive overloads and feedback which damages equipment.
Picard suggests using them to mask a subspace resonance signature in "The Pegasus" [TNG], although Data points out that their artificial nature would preclude their use in that circumstance - masking a warp core for several hours.
In "Caretaker" [VOY] , Voyager is scanned by a coherent tetryon beam before being transported across the galaxy.
Verterons also infest the Wormhole near Bajor. In "Playing God" [DS9], a proto-universe intruding into our own c/o subspace was kept contained by an energy field, but verteron pockets in the Wormhole threatened to release it, destroying a Runabout and perhaps even the Wormhole. Verterons and subspace do not mix well.
They also allow vessels to travel through the wormhole under impulse power ("In the Hands of the Prophets" [DS9]), and they appear in a display in Keiko's classroom on DS9 as the verteron membrane at the outer boundary of one side of the wormhole.
Tetryons are particles which are stable in subspace but unstable in normal space. They appear to be the main mediating particles of subspace interactions with normal space. They were introduced in "Schisms" [TNG] but they've shown up in "Force of Nature" [TNG], and a tetryon field is the result of an metaphasic shield interaction in "Suspicions" [TNG].
"What are 'warp particles'?"
These were mentioned in "Parallax" [VOY], and used to open a subspace breach in an event horizon.
The objection has been raised that warp particles have never been mentioned before. However, fields and particles are different ways of looking at the same thing. You can even consider soliton waves (cohesive waves which don't disperse) as being made up of a special soliton particle, or sound to be carried by a "phonon" particle, and it makes some calculations much easier than considering the wave or field classically.
Quantum mechanics says that for things like photons, electrons, Higgs bosons, etc, the particle/wave/field distinction is pretty much meaningless. So "warp particles" could refer to the specific particles making up a warp field, or the entire class of particles which partake in subspace reactions (tetryons, verterons, etc).
"What is subspace radio?"
A means of sending a signal through subspace, so that it is not limited by the speed of light. This is done by creating a subspace distortion which propagates in much the same way as an electromagnetic field. A large amount of energy is needed to send a signal any large distance, and the more energy that is available, the deeper the signal can be forced into subspace.
However, the signal dissipates over time, eventually releasing the energy that is left as an electromagnetic field. A more powerful initial signal can travel farther before this happens, but there is a limit; too much energy and the level of subspace that is used won't be tightly coupled to our own space-time any more, and the signal will probably go awry.
The Federation (and presumably other Alpha and Beta Quadrant groups) use subspace relay networks to periodically boost subspace signal strengths. We see one of these in "Aquiel" [TNG] and Seven of Nine uses one to "phone home" in "Hunters" [VOY].
"How fast is subspace radio?"
Under ideal conditions, Warp 9.9997. (TNG TM, page 99) This is "sixty times faster than the fastest starship, either existing or predicted" - assuming traditional warp technology.
The Encyclopedia says that with boosters and relays, Warp 9.9999 is the speed.
"Why is it instantaneous in the movies?"
No ad breaks.
"What is a cochrane?"
According to the Tech Manual, it's a measure of subspace distortion named after Zefram Cochrane, the inventor of warp drive. 1 cochrane is the distortion required to propel a ship at Warp 1, so field strengths are typically measured in millicochranes. It's shown up on TNG a couple of times amidst Geordi's technobabble.
According to the Star Trek Chronology, the Excelsior was commissioned as NX-2000 in 2284 as a test bed for the new TransWarp technology. By 2287, the TransWarp Development Project was deemed unsuccessful by Starfleet Command, and experiments were halted. "...The attempt to surpass the primary warp field efficiency barrier with the TransWarp Development Project in the early 2280s proved unsuccessful...." [TNG Tech Manual, p14]
It seems as though the designers were trying to get around the energy limits traditional warp entailed, after passing Warp 9. But what what is it? Is Transwarp just any "faster than warp travel" or is it a specific technology or natural occurrence?
In an IRC discussion with Boris S., Michael Okuda had this to say:
We were never clear on transwarp as seen in ST:III, but "Threshold" makes it clear that transwarp is the mysterious Warp 10 alluded to in earlier episodes. We assume that it is some kind of "deeper subspace domain" just as subspace presumably coexists with our own time-space continuum. In other words, we're not really sure.
If X is to transwarp as subspace is to warp, then perhaps X has the same relationship to subspace that subspace has to normal space? Trans-subspace? Is it turtles all the way down?
"What are Transwarp Conduits?"
The first Transwarp travel we saw onscreen was in "Descent" [TNG], which has the Borg using TransWarp Conduits. They're like custom-made wormholes that, once created, stay in place and can be used repeatedly. The conduits are used by broadcasting a tachyon signature which makes them open up and suck the ship in. They're beyond the ability of the Federation to create, but the Enterprise was able to use them once it recorded the tachyon signature the Borg were using. Transfer through the conduits is 20 times faster than the fastest warp available to Federation science (Warp 9.7 or 9.8), covering light-years in a matter of seconds rather than hours - just like a wormhole.
Chris Franklin points out:
[When] they followed Data's shuttle into the Conduit, Riker stated that they had covered 65 light years. I timed the trip with my stop watch and came up with about 9 seconds for their stay in the Conduit. This corresponds to about 227,911,132.04 times the speed of light.
That's a heck of a lot faster than speeds quoted above for Warp 9.9, even, far more than 20 times, so something is awry. Mike Brown reminds me that any attempt to measure the duration of some event on screen is misleading - "television shows are always a compressed, highlights-only telling of a story that typically spans several days" - even if the action seems continuous, so take any hard-and-fast numbers with a grain of salt.
Transwarp conduits appear to be tunnels through subspace (analogous to wormholes being tunnels through normal space?), bypassing the limitations of warp entirely.
"Transwarp Frogs in Space?"
And then there's "Threshold" [VOY] in which Voyager - a ship running low on supplies, with half its crew dead, stranded away from repair or research facilities, on the other side of the Galaxy from the Federation - manages to upgrade one of its never-ending supply of shuttles to make a Transwarp flight, something that has defied the best minds in the Federation for a century. There are a lot of things in this episode that many people wish had never seen the light of television, so we'll just focus on technobabble as it relates to warp travel.
The [TECH] isn't too bad, however. Warp 10 is identified clearly as infinite speed, but the pesky Warp 10 barrier is mentioned. Presumably, this is meant as the barrier to going at an arbitrarily large speed without draining the antimatter tanks and/or dilithium crystals and/or other ship components. When the shuttle does achieve Transwarp, it registers as Warp 10 and is everywhere at once for a brief time. Now that is the way to travel! Sensors also lose track of the shuttle, indicating that things in Transwarp do not interact with things in normal space, unlike warp travel. (Thanks to Vikash R. Goel for pointing that out.)
You can probably just ignore any parts of that episode that don't make any sense - various members of the Star Trek production crew have indicated that they plan to.
"What about Transwarp drive?"
Okay, now that the Star Trek writers are back to using this [TECH] buzzword there's no stopping them. Apparently, Transwarp can be used as a drive, just like warp drive. Given the way the name is used in various episodes, it appears to be a coherent technology exploiting a feature of the universe (a la warp) not just anything faster than warp. Civilizations a step above the Federation use it, and the basics are understood - at least by the Voyager crew - enough to detect its use and follow ships in Transwarp with their sensors.
The Voth in "Distant Origin" [VOY] use Transwarp drives (not to mention cloaks) even on small ships. This portrayal of Transwarp looks much more like just "really fast warp" than the conduits. Visually, the star streaks around the ship look fatter and longer than in warp, but it's otherwise just the same, only better.
And in "Scorpion" [VOY] Janeway refers multiple times to the Borg using Transwarp - which doesn't look at all conduitish.
"What is Quantum SlipStream Drive?"
Article by Jeremy H. Pace
From Webster's Dictionary:
In "Hope and Fear" [VOY] an alien race [Borg species designation 116] who are furious with Janeway's solving the Borg's species 8472 problem designs a fake experimental Starfleet ship for Voyager to "find" in the Delta Quadrant. Called the Dauntless, this ship appears to be of the same size or larger in mass than the Voyager, but has only minimal living space. The special hyperdrive is not warp but a new method called "quantum slipstream". An accidental jumpstart and research into the drive gives the following explanation: quantum energies from a quantum reactor in Engineering are funneled to the main deflector array, which then opens up a "quantum slipstream" in "slipstream space", a non-subspace dimension where incredible velocities can be attained.
Voyager uses the quantum slipstream (but not the Dauntless) to gain 300 light-years on their journey in only a few minutes, maybe an hour. They are forced to stop using the quantum slipstream because of the incredible stresses it puts on Voyager's hull.
In "Timeless" [VOY], it seems that Engineer Torres and the rest of the crew have managed to reverse-engineer the Dauntless' quantum reactor. Using Bedemite crystals and other exotic components, a quantum matrix is cobbled together that will allow for quantum slipstream travel. Ensign Harry Kim has doubts about the math, fears that are proven in holodeck simulation and in actual use. It turns out that Voyager runs into phase variant imbalances while using the quantum slipstream drive, making travel hazardous. After only a few minutes of travel, Voyager is forced to drop out of quantum slipstream space. The hybrid Torres drive is dismantled, and it is doubtful QSD will be seen again.
Seven of Nine does mention in "Hope and Fear" [VOY] that the QSD is similar in principle to the Borg's transwarp conduits (as opposed to the Voth's transwarp drive), so research into one drive system might yield clues about the other. A faked message from Starfleet claims the ship made 65,000 light-years in three months, which might put the velocity at 2,628,000 times the speed of light. Clearly, the quantum slipstream drive is a candidate for "extra-galactic travel" classification.
This is not warp, or a variation of warp drive. QSD appears to be based on a totally different principle than warp, Seven's statement notwithstanding. It is probable that due to the physics of QSD a ship would have to be made from scratch specifically for quantum slipstream. This is the difference between the species 116's Dauntless and Voyager's mimicry. In "Hope and Fear" [VOY] and "Timeless" [VOY] Commander Chakotay uses the phrase "alter our slipstream", implying that slipstream space is not free and open, but must be transversed in the form of grooves or pre-laid paths. This is seen as the cool blue "vortex" effect of QSD ships, as opposed to the sparkly lights of warp drive. Slipstreams appear to have only one setting: really, really, really (ludicrous) speed.
You cannot "see" truespace while in slipstream. You must orient your ship in the proper three-dimensional axis position, then activate the drive and time how long you want to travel before dropping out. You do not have to worry about local stars and gravity wells, since you are not in truespace, unlike warp drive.
It seems that a M/AMR is not needed for QSD ships. At least, none was seen in "Hope and Fear" [VOY].
It is possible to "fall" out of the slipstream, much as ships "fall" out of warp when their warp layers collapse. (It seems every time the ship does this it is a bad thing - helm control and shields are offline due to quantum effects. Maybe species 116 overcame this side effect?)
The theories from the [tech] newsgroup with the most weight are:
Sources: email@example.com; firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Sources: Rick Sternbach, Senior Illustrator, Star Trek Voyager, Paramount Pictures (with modifications using modern-day wormhole math); email@example.com
While theory #3 is obviously an early guess, and theory #2 has one of the ST:VOY team behind it, I myself prefer theory #1. With all respect to Mr. Sternbach, Star Trek has really bad wormholes physics (compared to modern-day cosmological math theories), and I'd like to avoid them at all costs. If the Borg's transwarp conduits are really similar to QSD as Seven stated, then theory #1 allows for decaying one-dimensional transwarp tunnels more stable than quantum slipstreams. It also explains why the Borg do not use QSD; transwarp is superior in the fact that it creates stable short-term conduits usable by other craft, cutting down on propulsion costs.
The necessary components for using QSD are:
"Besides TransWarp and Quantum Slipstream, what other alternate forms of FTL travel have we seen?"
In several episodes ("When the Bough Breaks" [TNG], "Tin Man" [TNG], "Q-Who" [TNG], "The Gift" [VOY]) some unknown technology or non-corporeal entity throws a starship tens, hundreds or thousands of light-years in mere seconds. In those cases there is rarely associated technobabble to hint at the underlying mechanism.
(I'm missing lots, please let me know.)
"FASA says the Enterprise-D uses UltraWarp, so nyeah!"
(FASA is a game publisher that produces games loosely based on the original and animated Star Trek series, and briefly had a license to produce TNG-era games. See the Reading FAQ for more background information.)
According to the TNG Tech Manual and Star Trek Chronology, the Enterprise-D uses the same old warp technology seen in TOS... just a much more advanced version.
The only hint that TOS, the classic films, and TNG warp drives might be different is in their visual appearance on screen - in the classic films the Enterprise "blurs" while in warp. We *have* seen the TNG Enterprise do this - in "Force of Nature" [TNG], when it field- saturated its nacelles and ran at high warp for 6 seconds. Perhaps the film-era warp drives used this field saturation to generate higher speeds at lower energy, an effect which was surpassed by later developments and obsolete by TNG?
"Some Starfleet ships use 3 nacelles!"
In 2269, Starfleet attempted ships with 1 and 3 or more warp nacelles (TNG TM p65). As previously thought, 2 is the most efficient, but 4 is apparently useful in some cases (Constellation Class, Cheyenne Class).
You need one nacelle to get anywhere, minimum. However, to yaw you need the nacelle to be split vertically (left and right halves) and to pitch you need the nacelle to be split horizontally (top and bottom halves). By using a split nacelle, you can induce slight timing differences, and cause the desired rotational effect (TM p65). This is a bit of a problem with one nacelle, since you end up with each warp coil divided into four segments. The TM indicates that matching *pairs* is difficult and very sensitive. Matching four, and providing four plasma injectors for each coil segment is probably difficult.
Having more than two nacelles (either 3 or 4) allows you to use only a single segment per coil. But the warp field itself requires a gap to be released! (TM p65) (For anyone who doubts this, in "Eye of the Beholder" [TNG], we see TNG TM fig 5.3.3 reproduced on a large screen display with labels.)
So you need to have the warp coils split in two anyway; if you use the top/bottom split to provide pitch control, and two nacelles to provide yaw control, you're set.
On some designs, four nacelles may be the way to go; even with the required split, being able to tune the warp field discreetly may be enough of an advantage to warrant using four nacelles.
"Ha! Three nacelle ships are canon!" ("All Good Things..." [TNG])
Note that a number of things have changed by the time we see the U.S.S. Enterprise zipping around with three nacelles in that episode:
My own explanation: new nacelle designs allow ships like the U.S.S. Pasteur to cruise at Warp 13 without frying space-time. Older ships, like the Enterprise, can be refitted with a third nacelle (and other wingdings and widgets) to clean their subspace emissions, so to speak. The third nacelle also allows a more powerful field to be generated, to drive the ship around at Warp 13, but this goes beyond TNG-era knowledge of subspace mechanics.
So as far as strictly TNG-era ships are concerned, three nacelles are still worse than useless.
"But the Ferengi/Borg/Klingon Bird of Prey don't have nacelles!"
The Borg probably have subspace field generators (redundantly) scattered throughout their cube; they can then pulse them to generate *massive* overlapping, pulsating subspace fields in any direction. Same technique, more power, more flexibility.
As for Ferengi, perhaps they use shielding. One thing is certain; the design of Ferengi ships allows for the ship to be contained in a single lobed warp field. The Enterprise requires a double lobe. Having "inboard" warp drives (like the Bird of Prey) gets you a fast ship for less power; likely, shielding can prevent the fields from frying the crew.
A display screen in "Blood Oath" [DS9] may show the warp field of the Bird of Prey - again, a single lobe.
Something to consider; most of the small ships (picture the raiding ship from "Gambit" [TNG]) don't have outboard drives. They probably make the single-lobe/shielding tradeoff to keep their ships small, fast and cheap. Ditto for shuttles with warp.
"Why do ships always meet the same way up?"
I know it's been proposed as a joke, but the idea that warp travel requires a universal "up" isn't as silly as you might think. We know that things in normal space affect subspace. What if the mass and orientation of the entire galaxy, which is nothing to sneeze at, affect subspace in such a way as to make travel more efficient if your warp fields are generated parallel to the plane of the galaxy?
It's then more efficient for ships to align their warp drives with the plane of the galaxy, so flying "up" and "down" in the galactic plane (which is relatively thin, about 1/10th to 1/40th the diameter of the galaxy) would take more energy. This also explains the banking into turns and such.
If you have galactic-up and galactic-down to choose from, why always the same way up? Probably a matter of protocol. Only "loser" races don't adhere to the standard. You'll also note that many small ships are vertically symmetrical, perhaps as their designers aren't quite up to snuff when it comes to designing warp drives.
More support for this hypothesis: warp does really weird things at the edge and at the center of the galaxy. The Great Barrier of TOS fame ("Where No Man Has Gone Before" [TOS] and "By Any Other Name" [TOS]) at the edge of the galaxy and the one near the center of the galaxy (if you believe in Star Trek V) were each considered impassable and gave the Enterprise a rough ride.
Kirk made a number of references in "By Any Other Name" [TOS] about warp drive not working outside the galaxy, or something to that effect. While the Kelvans of Andromeda had got that licked, this does give the theory a little bit of support.
Another note: the subspace shockwave seen in Star Trek VI was both planar and aligned with the direction of the Excelsior's vertical axis, and shockwaves within the subspace rift of "Force of Nature" [TNG] were also aligned coplanar to the ship.
Pete Carr points out the following bit of dialog from "Genesis" [TNG]:
Picard: Adjust the axial stabilizers [of the shuttle] to match the attitude and rotation rate of the Enterprise.
A "universal up" would explain why this sort of thing doesn't happen all the time; only drifting ships like the Enterprise need help.
See the Reading List FAQ for more details on the reference volumes mentioned above and below.
The question of "what is canon" has been argued for years in the Star Trek newsgroup hierarchy. In the realm of technical discussions, this can be refined to the question of "what evidence is factual, and what is apocryphal". These FAQs follow the currently dominant notion that "canon" is aired live-action material and nothing more, with the caveat that materials produced off-camera by the production crew are often (but not always) reliable predictors of the direction future canonical material will follow, and are therefore granted a special "quasi-canonical" status. Any other material falls into the realm of speculation - it may be perfectly well grounded speculation useful for building up technical arguments, or wild flights of fancy that have no rational basis.
In addition, more recently presented information is considered to supercede old information, unless the weight of the evidence supports the original data. While this may seem highly biased and may be eyed with some skepticism as a form of Orwellian "newthink", it is a more useful predictor of what those directly responsible for the creation of the series are likely to include as canonical material in the future.
For example, the excellent and groundbreaking Star Fleet Technical Manual, by Franz Joseph created in the 1970's was a very well thought out look at the technical world of Starfleet just slightly beyond what was seen in the original series. Unfortunately, and perhaps for purely arbitrary reasons, the future development of "canon" Star Trek diverged from this speculation. This in no way implies that there was anything wrong with that volume or any others, merely that due to later "evidence", it can no longer be regarded as an authoritative overview of Trek technology. On the other hand, the author performed a lot of research to create it, and therefore its speculation should not be dismissed out of hand.
That said, we are dealing with a universe in the process of being created by scores of (usually) non-technical people, aiming to provide weekly entertainment for a mass audience. There are many inconsistencies even amid the canonical material, and often times the wildest speculation on the newsgroup makes more sense than what we see in the episodes.
Highly regarded, but non-canonical material:
Joshua Bell, firstname.lastname@example.org