Impulse Drive: What do we know? (Non-canon speculation)

[blssdwlf]

And I again point you to the space shuttles OMS engine pods which are proportionally even higher above centerline.

Those OMS engine pods are there for orbital purposes not for flying between planets with the nose level. If you were trying to make the claim that OMS position = impulse engine position for Reliant then I would have liked to see the Reliant flying around in a nose-up position in the Mutara Nebula

 

[Timo]

...Indeed, having things off the thrust axis in starships is like having things off the sagittal centerplane in aircraft. Planes that only have left wings or right engines don't fly particularly well. They exist all right (see e.g. Blohm&Voss BV 141), but one has to have a very special rationale for designing such asymmetry. Unless one is working for George Lucas, of course.

Timo Saloniemi

 

[John O.]

Over-expansion doesn't occur INSIDE the nozzle, though, and can be prevented by adding a properly shaped nozzle extension. Effective exhaust velocity is measured at the nozzle end, not the throat of the combustion chamber, so a nozzle extension that increases exhaust velocity by redirecting exhaust downstream.

Yes. It does.

http://www.aerospaceweb.org/question/propulsion/q0220.shtml

Nozzle extensions can't just be thrown onto a nozzle and fix all your problems. Nozzle extensions reduce overexpansion because they increase the area ratio, not because they increase effective exhaust velocity (it's sort of saying the same thing but it misses the actual physics going on to say that the problem goes away if you increase exhaust velocity) - but pressure thrust losses are a function of altitude, so you can't just stick just a nozzle extension onto a nozzle while a rocket is sitting on the pad and expect it to solve your overexpansion issue at altitude without screwing up the rest of your flight regime. Thrust at LOWER altitudes will be completely different, specifically, it'll be lower. If somebody designed a rocket with a given area ratio and then slapped a nozzle extension on it to solve overexpansion at high altitude, your sea level thrust would go to shit - because higher area ratios are NOT optimized for sea level operation. Think about it - longer nozzle, larger area ratio, more time for the fluid to expand - the exit pressure is going to take a dive, and since pressure thrust is (pe-pa)*Ae, it's going to become negative and work against the momentum thrust.

This is exactly why nozzle extensions aren't actually used. The only useful ones have to be altitude-adaptable, which is difficult to engineer. Good paper on this exact subject:

http://www.lpre.de/resources/articles/Advanced_nozzles.pdf

 

[Crazy Eddie]

And I again point you to the space shuttles OMS engine pods which are proportionally even higher above centerline.

Those OMS engine pods are there for orbital purposes not for flying between planets with the nose level.

Which makes no difference whatsoever since the engines still have to produce forward acceleration.

If you were trying to make the claim that OMS position = impulse engine position for Reliant then I would have liked to see the Reliant flying around in a nose-up position in the Mutara Nebula

Space ships do not "fly" that way. The ship would only accelerate when the impulse engines are active, otherwise it would simply coast.

 

[Crazy Eddie]

Over-expansion doesn't occur INSIDE the nozzle, though, and can be prevented by adding a properly shaped nozzle extension. Effective exhaust velocity is measured at the nozzle end, not the throat of the combustion chamber, so a nozzle extension that increases exhaust velocity by redirecting exhaust downstream.

Yes. It does.

http://www.aerospaceweb.org/question/propulsion/q0220.shtml

I guess the problem we're having is it's been fifteen years since I did anything in aerospace engineering and keep forgetting to reverse over/under expansion.

The other problem is you're having way too much fun showing off the fruits of your exams. For example:

Nozzle extensions can't just be thrown onto a nozzle and fix all your problems.

And somebody claimed they could? You know as well as I do that ANY given nozzle shape is ideal for a specific altitude range. If your engine has a sub-optimal expansion ratio, it's because it has the wrong nozzle for that altitude. Why you would continue to point this out after I said the same thing three posts ago is beyond me... except maybe that you still have exam notes swarming around your brain and are trying to dump them like a 4chan thread.

On the other hand::

If somebody designed a rocket with a given area ratio and then slapped a nozzle extension on it to solve overexpansion at high altitude...

They would have to turn the engine into an aerospike.

This is exactly why nozzle extensions aren't actually used.

They are for upper stage engines, especially kerosine-fueled ones with relatively low ISPs. Some hypergolic engines use them as well.

 

[blssdwlf]

And I again point you to the space shuttles OMS engine pods which are proportionally even higher above centerline.

Those OMS engine pods are there for orbital purposes not for flying between planets with the nose level.

Which makes no difference whatsoever since the engines still have to produce forward acceleration.

Sure it does make a difference. The OMS is there to help in orbital maneuvers that typically involve moving the shuttle higher or lower in orbit or prep for re-entry. That's got nothing to do with propelling it to Saturn with her nose aimed at it.

If you were trying to make the claim that OMS position = impulse engine position for Reliant then I would have liked to see the Reliant flying around in a nose-up position in the Mutara Nebula

Space ships do not "fly" that way. The ship would only accelerate when the impulse engines are active, otherwise it would simply coast.

"I'm laughing at your superior intellect." The Reliant accelerated at impulse straight without a hint of nose-up or down going after the Enterprise. I agree that Star Trek ships do not "fly" like real spacecraft, but we already knew that

 

[Crazy Eddie]

Those OMS engine pods are there for orbital purposes not for flying between planets with the nose level.

Which makes no difference whatsoever since the engines still have to produce forward acceleration.

Sure it does make a difference. The OMS is there to help in orbital maneuvers that typically involve moving the shuttle higher or lower in orbit or prep for re-entry. That's got nothing to do with propelling it to Saturn with her nose aimed at it.

That's because you can't GET to saturn by aiming your nose at it. Because IN REALITY, Saturn is constantly in motion, and so is your ship, so if you power out of orbit with your nose aimed at saturn, it doesn't matter how your engines work because you still have to cancel the component of your velocity that ISN'T in the direction of Saturn.

If you put a bottomless propellant tank on the shuttle those two OMS engines could take it anywhere in the solar system and back again. It could use an ordinary Hohman transfer (about 3 years) or a long-burn hyperbolic accelerating all the way there (about 3 months). In NEITHER case is it as simple as "point your nose and fire the engines," because real space craft don't work that way.

Stylized VFX notwithstanding, unless Star Trek is a parallel universe where the laws of celestial mechanics don't apply, neither do starships.

"I'm laughing at your superior intellect." The Reliant accelerated at impulse straight without a hint of nose-up or down going after the Enterprise.

To be sure, Reliant was in a level orientation when she accelerated. Considerably less clear is precisely which DIRECTION Reliant was accelerating. An accelerating vector 5 to 10 degrees down from the bow (as in the case of the shuttle) wouldn't be evident from that angle.

I agree that Star Trek ships do not "fly" like real spacecraft, but we already knew that

Well, they fly like models on mechanically controlled stands. But we're sitting here trying to figure out how they probably "really" work as if Trek was a real thing. This isn't like the whole weapons range issue where a ship is quoted at being a thousand kilometers away and then two seconds later they're pounding each other from five hundred feet; there's PLENTY of wiggle room in the visuals here.

 

[blssdwlf]

Which makes no difference whatsoever since the engines still have to produce forward acceleration.

Sure it does make a difference. The OMS is there to help in orbital maneuvers that typically involve moving the shuttle higher or lower in orbit or prep for re-entry. That's got nothing to do with propelling it to Saturn with her nose aimed at it.

That's because you can't GET to saturn by aiming your nose at it. Because IN REALITY, Saturn is constantly in motion, and so is your ship, so if you power out of orbit with your nose aimed at saturn, it doesn't matter how your engines work because you still have to cancel the component of your velocity that ISN'T in the direction of Saturn.

Then IN REALITY, the shuttle can't GET to saturn by aiming its nose at where it will intercept either. Still doesn't matter since the OMS isn't going to allow aiming the nose of the shuttle at anything for a interplanetary trip as it wasn't designed for that.

If you put a bottomless propellant tank on the shuttle those two OMS engines could take it anywhere in the solar system and back again.

Yeah, with the nose aiming "up" from it's final destination during the acceleration phase

Stylized VFX notwithstanding, unless Star Trek is a parallel universe where the laws of celestial mechanics don't apply, neither do starships.

Why not? Overpowered ounce of antimatter, ships at sublight coasting to a stop when power is lost. Yep, that's easy - a parallel universe - where there was a Eugenics War in the 90's, extra Voyager probes sent into deep space, etc etc

"I'm laughing at your superior intellect." The Reliant accelerated at impulse straight without a hint of nose-up or down going after the Enterprise.

To be sure, Reliant was in a level orientation when she accelerated. Considerably less clear is precisely which DIRECTION Reliant was accelerating. An accelerating vector 5 to 10 degrees down from the bow (as in the case of the shuttle) wouldn't be evident from that angle.

We have a nice aft angle view from the Enterprise's main viewer when the Reliant accelerated. No tumbling nose down, no compensating nose pitch up.

I agree that Star Trek ships do not "fly" like real spacecraft, but we already knew that

Well, they fly like models on mechanically controlled stands. But we're sitting here trying to figure out how they probably "really" work as if Trek was a real thing. This isn't like the whole weapons range issue where a ship is quoted at being a thousand kilometers away and then two seconds later they're pounding each other from five hundred feet; there's PLENTY of wiggle room in the visuals here.

The weapons range issue is a TNG and on problem We're still chatting about how impulse engines don't appear to care where they are located.

 

[John O.]

You know as well as I do that ANY given nozzle shape is ideal for a specific altitude range. If your engine has a sub-optimal expansion ratio, it's because it has the wrong nozzle for that altitude.

Or, every nozzle is "the wrong nozzle" for every altitude but one - that's why I take issue with the term "the wrong nozzle" or the characterization of that nozzle design as flawed. It's not. It's just a reality, it always happens.

Although, as a side note, I'm told by someone that the shuttle engines don't work this way, that they accepted a 'slightly lower than optimal' performance for a range of altitudes rather than a perfect optimal performance at one altitude.

 

[Crazy Eddie]

Then IN REALITY, the shuttle can't GET to saturn by aiming its nose at where it will intercept either.

Yes it can, depending on when you perform the burn.

Why not? Overpowered ounce of antimatter, ships at sublight coasting to a stop when power is lost. Yep, that's easy - a parallel universe - where there was a Eugenics War in the 90's, extra Voyager probes sent into deep space, etc etc

If we're going to completely ignore real physics altogether, then why would we even CARE how the impulse engines work? Just put a couple of hamsters in a wheel and call it magic.

We have a nice aft angle view from the Enterprise's main viewer when the Reliant accelerated. No tumbling nose down, no compensating nose pitch up.

Why would you expect it to tumble? It's still thrusting through the center of gravity, it's just not thrusting through the "bow" of the ship, but at a point five to ten degrees below it, which wouldn't be evident from the viewscreen image as this would constitute a direction change of a few meters per second for every hundred.

The weapons range issue is a TNG and on problem

Then if we ignore TNG and on, it isn't an issue at all. TOS effects aren't consistent enough for us to know the ship's acceleration angle of attack, and neither are the movie effects. And the relatively high probability of thrust-vectoring forcefields as a basic part of Starfleet impulse engines cannot be ignored either.

 

[Crazy Eddie]

You know as well as I do that ANY given nozzle shape is ideal for a specific altitude range. If your engine has a sub-optimal expansion ratio, it's because it has the wrong nozzle for that altitude.

Or, every nozzle is "the wrong nozzle" for every altitude but one - that's why I take issue with the term "the wrong nozzle" or the characterization of that nozzle design as flawed. It's not. It's just a reality, it always happens.

No it doesn't always happen, because nearly ALL modern rockets used staging and an upper stage rocket will never be used at sealevel, nor will a sea-level rocket be used in orbit. That's what I mean by "the wrong nozzle." If you try to use a basic bell nozzle on an upper stage engine, you've got the wrong nozzle. If you use a conic section nozzle on a lower stage, you've again got the wrong nozzle.

Although, as a side note, I'm told by someone that the shuttle engines don't work this way, that they accepted a 'slightly lower than optimal' performance for a range of altitudes rather than a perfect optimal performance at one altitude.

The fact is the SSMEs do have an optimal altitude. It's just that the shape of the nozzles sacrifices some performance at that "butter zone" to allow increased performances in other altitudes.

 

[John O.]

For once I can agree , that the nature of staging mitigates the losses - but remember, staging isn't explicitly done to overcome this problem, it's done to improve payload fraction. Operation at off-design altitudes still happens despite staging because there other considerations that determine where the stage cutoff points are other than where this optimal altitude is and where the rocket departs from it (by where, I mean altitude). There are so many design factors involved, I can't say for certain b/c I've never worked on a design team that's going to fly a liquid chemical rocket nozzle, but I can say with almost 100% certainty that design teams aren't able to make the optimal altitude the stage burnout altitudes.

 

[trekkist]

Changing the topic (back to 'what do we know?'), each Trek incarnation provides evidence of impulse's being ftl-capable.

TOS
"Where No Man" -- Valiant reached galactic edge on impulse
"Corbomite Maneuver" -- impulse thrust added to warp in escape maneuver, meaning its increment of thrust worth being added to warp's
"Metamorphosis" -- Cochrane cited as having "discovered" the "space warp," not as having invented warp drive
"Doomsday Machine" -- both starships outpaced the DM on impulse
(This in addition to the Romulan's "simple impulse")

"Wrath of Khan" -- Enterprise completed what had been quoted as a 5+ hour journey to Regula before rigor set in among Khan's victims...which oddly enough yields a speed of warp six, cited in dialogue asconstituting "full impulse" in:

TNG
"Conspiracy"

And then there's:
"Arsenal of Freedom" -- Geordi conducts a saucer seperation after performing a dead stop, then orders Argyle to proceed elsewhere in the impulse-driven saucer (which made Farpoint in its own in the pilot)

ST VI -- Sulu's Excelsior is heading home on impulse at the film's beginning

Voyager has a reference too, though it escapes my memory.

Obviously, some of these are debatable and/or otherwise interpretable. But I don't think they all are. Impulse must, it seems to me, be a hyperlight-capable system, in use previous to warp drive ("Enterprise" notwithstanding), and most likely non-Newtonian in ANY capacity. After all, one could hardly go "reverse impulse" ("Corbomite Maneuver") with a fusion drive...

 

[Timo]

"Where No Man" -- Valiant reached galactic edge on impulse

Or more exactly, was said to have fought against the galactic barrier with her "old impulse engines", in vain. Her main propulsion might have been warp, or the explicitly mentioned space storm might have swept her to that location.

"Corbomite Maneuver" -- impulse thrust added to warp in escape maneuver, meaning its increment of thrust worth being added to warp's

Or more exactly, impulse power.

"Metamorphosis" -- Cochrane cited as having "discovered" the "space warp," not as having invented warp drive

And having done so well before the first indicated interstellar voyage by humans.

"Doomsday Machine" -- both starships outpaced the DM on impulse

But didn't depart the star system in the process or anything, leaving open the possibility that the DDM was limited to impulse as well.

Enterprise completed what had been quoted as a 5+ hour journey to Regula before rigor set in among Khan's victims.

It's noteworthy that she was already down to impulse when quoting the 5+ hours; possibly, the region was unconductive of warp travel (cf. the Mutara nebula), and warping to Regula would never have been an option.

Geordi conducts a saucer seperation after performing a dead stop, then orders Logan to proceed elsewhere in the impulse-driven saucer

But nobody ever claimed the saucer would be impulse-driven. Not on screen, that is. as said, she performs a high-warp journey in the pilot episode already.

Sulu's Excelsior is heading home on impulse at the film's beginning

Or more exactly, is starting to head home. When we join the action, Sulu is being given the PADD that tells him he has completed his mission and can go home.

But I don't think they all are.

Oh, I do think they all are. Or those that aren't are clear-cut cases in favor of impulse being STL-only.

Timo Saloniemi

 

[trekkist]

Timo,

"Where No Man" -- a "magnetic space storm" swept them at least 10,000 light years? From a sublight start? A fascinating example of space weather never again cited in any Trek. As for the possibility of the line reading "the old impulse engines weren't strong enough [to resist the storm]" -- yes, it's possible Valiant had warp (which for some reason was of no use in fighting the storm...). But I think the clear implication of the line is she didn't. Just an opinion, mind you.

"Corbomite Manuever" -- impulse thrust, impulse power -- same difference. After all, there's NO indication impulse is a GENERATOR of "power" (as it might be argued warp is...depending on how one interprets the phrase "warp power to the shields"). In either case (thrust or power), for the addition of impulse to warp to make a difference, it had to be a significant fraction of warp...a multi-light level of "power."

Don't know what the "Metamorphosis" dismissal is, unless it's meant to contrast the TOS Cochrane's dates with that of the film Cochrane. If so, wouldn't the first take priority? Personally, I abhor retcons.

"Doomsday Machine" -- canNOT have been [sublight] impulse only, or it wouldn't have been able to eat four star systems in short order, and present an imminent threat to Rigel's.

"Wrath of Khan" -- an outright error, Timo. Enterprise was at warp five when the 5 hrs 43 minutes figure was cited.

In ST VI, Sulu is logging on the PADD...reporting being headed home on impulse.

>"...nobody ever claimed the saucer would be impulse-driven. Not on screen, that is. as said, she performs a high-warp journey in the pilot episode already."

In the pilot, she completes a warp-speed flight. In "Arsenal," she is about to initiate one. If the saucer has warp drive, where are her nacelles?

Not to mention "Conspiracy's" "full impulse" of "warp six."

I think you're staining at gnats, Timo. No offense intended. I know heresy is a hard sell. But y'know, I also recall the decades during which shuttlecraft were deemed sublight-only...despite their warp nacelles, intersteller journeys, and trails of "antimatter particles" ("Metamorphosis").

 

[Timo]

a "magnetic space storm" swept them at least 10,000 light years? From a sublight start? A fascinating example of space weather never again cited in any Trek.

Trek is full of phenomena that fling starships across thousands of lightyears. Kirk encountered many of them, and his predecessors might have been aware of a few, too. After Kirk, there'd be plenty of discoveries, and the naming of the things might change. The space storm that moved the Valiant might be dubbed a subspace fold or a tachyon eddy or a wormhole by 24th century scientists.

Certainly the idea of space phenomena displacing starships is a Trek stape and perfectly fits the dialogue of "Where No Man".

impulse thrust, impulse power -- same difference. After all, there's NO indication impulse is a GENERATOR of "power"

But every indication that something generates power for impulse. And it's separate from that which generates power for warp, because the starship still has impulse after the power system of the warp drive has been damaged or sabotaged (e.g. "Elaan of Troyius").

So "impulse power" is "power normally used for impulse" more likely than not.

Whether we use that interpretation to take care of "Balance of Terror", too, or simply say that Scotty was mistaken, is up to the audience to decide.

Don't know what the "Metamorphosis" dismissal is

That's probably because the original argument made no particular sense. Who cares what Cochrane discovered and how? The point is that humans had warp when they went to the stars, and had no need for interstellar impulse. This doesn't seem to serve as evidence for FTL impulse at all, then.

"Doomsday Machine" -- canNOT have been [sublight] impulse only, or it wouldn't have been able to eat four star systems in short order, and present an imminent threat to Rigel's.

It's quite possible the DDM can't fight at warp even if it can cruise at that speed. After all, if FTL impulse were possible, then it would be of no consequence that the Enterprise loses warp drive in the fighting - she could overtake the DDM at impulse then, even between the stars, and protect Rigel either en route or at Rigel. Instead, the loss of warp creates a situation where even the reluctant Spock has to fight the decisive battle at L-374.

Enterprise was at warp five when the 5 hrs 43 minutes figure was cited.

When the ship first goes to warp five, ETA is not given. One scene later, ETA "at present speed" is either 5 or 12 hours (several transcripts give the latter for Nimoy's delivery) and 43 minutes. Then follows the Genesis briefing, which takes minutes rather than hours, and then the Reliant is met and action becomes impulse only.

At no point does Kirk order his ship out of warp, though. When the two ships meet, both are at impulse, but only Khan commands a speed change. So it seems that "present speed" for Kirk was actually impulse when the ETA was given.

In ST VI, Sulu is logging on the PADD...reporting being headed home on impulse.

Exactly. And the timepoint is shortly before the mission has ended. At which time every Trek captain would be at impulse rather than at warp. That's no proof that he'd stay at impulse after his charting mission ended.

In the pilot, she completes a warp-speed flight. In "Arsenal," she is about to initiate one.

So clearly she's warp-capable. Why complicate matters with baseless speculation?

If the saucer has warp drive, where are her nacelles?

Not all Federation starships need nacelles for warp (see the Defiant and her two shuttle types, or various other shuttles and small craft). Most have some sort of a blue-glowing window somewhere, though - and the saucer has plenty of those, on the upper aft section.

And never mind that most aliens have no taste for nacelles in their warp drives, proving that nacelles are superfluous for warp.

Not to mention "Conspiracy's" "full impulse" of "warp six."

What mention does that warrant?

I think you're staining at gnats, Timo.

One learns something new every day; I'll use that some day. Thanks!

But you don't seem to have much actual evidence for the FTL impulse idea. All of the above arguments seem to have come to naught, unless you have some sort of an ace in the sleeve with LaForge's "Aye, full impulse" thing...

Timo Saloniemi

 

[John O.]

I don't think nacelles should be considered superfluous simply because other spacecraft designs don't need them; a nacelle is just a housing for a warp coil and numerous other related systems. Alien design technologies just may house them differently.

 

[C.E. Evans]

I imagined the nacelles of a Cardassian Galor-class warship to be those large wing-like structures near the bow...

 

[Timo]

I don't think nacelles should be considered superfluous simply because other spacecraft designs don't need them; a nacelle is just a housing for a warp coil and numerous other related systems. Alien design technologies just may house them differently.

Agreed on that last bit - which makes me think nacelles indeed are superfluous, or at least far from mandatory. The E-D saucer may house her warp engines "differently" as well.

I imagined the nacelles of a Cardassian Galor-class warship to be those large wing-like structures near the bow...

That's where the ship has the glowing bits, at least. But some alien designs go to warp without much in the way of glowing bits, suggesting that completely "internal" warp drives are also an option. Perhaps one calling for advanced tech (like with the Borg) or imposing severe performance penalties and being mainly used by primitives (like with e.g. the Pakleds)? OTOH, Kirk's old ship didn't have much glow...

Timo Saloniemi

 

[trekkist]

• “Where No Man”

I recall no NATURAL phenomenon being cited as driving a vessel or object over interstellar distances. Entities did that; beings opened “warps in space” and so forth. Enterprise (not a “natural object”) took a “jump” out of Tholian space…but in that case (as any other you might mention), reference was made to the oddity of the event. “Where No Man” mentions nothing save the storm itself…a phenomenon which, whatever it might be called, is unique to that episode.
​

• “Corbomite Maneuver”

Whether “impulse power” refers to “power from some source, normally assigned to impulse propulsion” OR “the thrust/speed applying ‘power’ of the impulse drive” is irrelevant. In either case, said “power” would be such a minute fraction of that applicable to warp drive its addition TO warp’s in an emergency would make no appreciable difference…IF impulse “power” is sufficient ONLY to apply a velocity of less than lightspeed.
​

• “Metamorphosis”

What matters about Cochrane’s having “discovered the space warp” as vs. “invented the warp drive” is that the term warp DRIVE was in common series usage at the time of the episode. If we are to take dialogue (or anything else) as reflecting an underlying “reality” that the series does NOT necessarily spell out, that distinction (“discoverer of THE…warp” as vs. “invented the…drive”) MUST mean something. Now, what might it mean? In isolation, the question would be unanswerable and pointless. But the reference is NOT in isolation, but consistent with many another impulse reference.
​

• “Mudd’s Women”

SPOCK: There's a lithium mining operation on Rigel 12. High-grade ore, I've heard.
KIRK: Location and distance.
SPOCK: Mister Farrell has the course. Less than two day's travel.
KIRK: Make for Rigel 12, Mister Spock.
SPOCK: Rigel 12, Mister Farrell. You have the course.
Captain's log, Stardate 1329.2. On board the U.S.S. Enterprise, a ship's hearing is being convened against the transport vessel's captain. I'm becoming concerned about the almost-hypnotic effect produced by the women.
[Mudd’s hearing…during which they lose their last lithium crystal]
Captain's log-- Stardate 1330.1. Position, fourteen hours out of Rigel 12. We're on auxiliary impulse engines. Fuel low, barely sufficient to achieve orbit over the planet. Lithium replacements are now imperative. The effect of Mudd's women on my crew continues to grow, still totally unexplained. Harry Mudd is confined to his quarters under guard.

Seems pretty self-evident they proceeded to complete…lithium-less and without warp drive…what had very shortly previously been a two day journey. Two days some time prior to Stardate 1329.2…fourteen hours at 1330.1. Yeah, I know we don’t know how long a Stardate’s decimals are…I know we don’t know how long elapsed between the two day citation and the log entry…but honestly Timo, if you’re not straining at gnats to refute this I’d like to know what you’d call it…
​

• “Corbomite Maneuver”

Another one I forgot. How do they FIRST attempt flight from the radiation-emitting cube? Do they warp away? Nope; they engage aft impulse! Why? Wouldn’t warping off make more sense? It would…if ONLY warp could apply hyperlight motion…
​

• “Doomsday Machine”

A complex case, needful of extensive quotation. Sole point of (I assume?) agreement, the Machine must be ftl-capable, or Rigel wouldn’t be in danger for years (at least).
​

PALMER: The distress call definitely came from one of the solar systems in this sector.
KIRK: Can you pinpoint it any closer, Lieutenant?
PALMER: Negative. It was so badly garbled all we got was the name Constellation, then we lost it.

Implication is Enterprise detected the distress beacon at some (greater) distance than her present position (un-emphasized weight on THIS sector, subsequent to a pre-telecast order of “Head for it” on Kirk’s part), but not very long ago (Palmer is only now reporting the ship’s name). HOWEVER, it might alternatively be that subspace interference prevented the ship’s name being “legible” at a greater distance; after all, enough time must have elapsed since the beacon’s activation for Constellation’s crew to at least evacuate, if not die.
​

SULU: Entering limits of System L-374, sir. Scanners show the same evidence of destruction.
KIRK: Every solar system in this sector blasted to rubble and still no sign of the Constellation. Matt Decker's in command. What could have happened to him?

“Entering limits of system” doesn’t translate to “dropping from warp.” After all, “limits” would be some four light hours from the star, right? (per Pluto’s orbit).
​

SPOCK: I have it on the sensors, Captain. By configuration, a starship stopped in space. She appears to be drifting.
PALMER: No answer, Captain. All I get is the automatic beacon.
SPOCK: Sensors not recording normal energy output.
KIRK: Approach course, Mister Sulu.

Approaching at what speed? Still, one would guess, warp. Spock’s reading configuration (shape) may imply a “relatively” near distance, but sensor range is a full parsec (per “Enterprise Incident”). My take is they’re still light-hours from Constellation.
​

KIRK: Very good. Initiate a full sensor scan of the immediate area for any other vessel.
SULU: Aye, sir.

[irrelevant – in Cthulhu’s name I swear – lines omitted]
​

SULU: No other vessels in the area, Captain. All scanners show clear.

So where’s the doomsday machine? Being as how NO reference was made to sensor range and/or detection impediments, one must assume, over a parsec away…i.e., en route to its next meal (rather than hovering locally, burping off its last)
​

WASHBURN: We made a complete check on structural and control damage, sir. As far as we can tell, something crashed through the deflectors and knocked out the generators. Somehow the antimatter in the warp drive pods has been deactivated.
KIRK: Deactivated? Scotty, could some kind of general energy dampening field do that, and would the same type of thing account for the heavy subspace interference?

These lines are of significance in explicating what the machine’s response is to ships: to render them useless (i.e., of no danger to itself). It doesn’t eat them; it doesn’t utterly destroy them. It deactivates them, then goes on its merry way.
​

SPOCK: It came up on us fast, Captain, but we seem able to maintain our distance.

“Came up on us fast” from where? From out of sensor range. We enter unknown territory here, in that one interpretation is the machine dropped from warp not quite within its own weapon range, and commenced a “firing pass.” But--
​

KIRK: Whatever it is, we can't let it go beyond us to the next solar system. We have to stop it. If it's a robot, what are the chances of deactivating it?
[Bridge]
SPOCK: I would say none, Captain. The energy generated by our power nacelles seems to attracts it. I doubt we could manoeuvre close enough without drawing a direct attack upon ourselves.
[omitted line]
SULU: It's closing on us, Mister Spock.
SPOCK: Closing, Captain.

--what are the odds Spock…upon Enterprise’s being approached by a planet-eating, anti-proton beam-wielding, nacelle-deactivating THING…wouldn’t maneuver away AT WARP??? None, I would guess…particularly once Sulu says “It’s closing.” Is Spock remaining sublight (circling the Constellation, say) to remain in communications or transporter range? Maybe. But that would be a helluva tight circle, in the latter case…some tens of thousands of miles, per Making of ‘Star Trek,’ at just under lightspeed, without the crew’s reacting at all to the centripetal, as in a ‘hard over’ turn…which in this case would be constant. And all without ANY reference or order being given. If dialogue reflects reality, it makes more sense to presume Enterprise was at warp, and on Kirk’s order to drop shields and beam, Sulu (not needing an explicit command) turned back toward Constellation for a “beaming pass.”
​

SPOCK: Captain, we've been attacked. The transporter is damaged. We're taking evasive action.
PALMER: Mister Spock, communication's damaged. We're unable to override interference.

Warp drive undamaged at this point. Obviously they’re using it.
​

SPOCK: Impulse and warp engines operative, transporter and communications under repair. Random chance seems to have operated in our favour.
[omitted]
SULU: It's veering off, back on course for the next solar system. The Rigel colony, sir.
SPOCK: Evidently programmed to ignore anything as small as a ship beyond a certain radius. We'll maintain a discreet distance and circle back to pick up the Captain.

Yep, they’re at warp. Which means they chase the thing down at warp, engage it at warp, and are stripped of warp at warp. Leaving them to be pursued over whatever distance they give chase/conduct battle at warp by the impulse-driven Constellation.
​

SPOCK: It has ceased fire. We're being held in a tractor beam. We're being pulled inside, Commodore. You must veer off.
DECKER: Maintain phaser fire, helmsman.
SPOCK: We have lost warp power. If we don't break the tractor beam within sixty seconds, we never will.

A confirmation that impulse “power” is insignificant compared to warp “power.” Without the latter, they can’t break free. Why? Because they’re being pulled closer. In one minute, they’ll be so close impulse will be insufficient to break the tractor…as it can (so Spock thinks) at the PRESENT distance.
​

DECKER: Kirk pulled us out of there by distracting it. Now it's our turn. Fire phasers. (they do) We did it! Hard about. Give me some distance.
SULU: We're moving away, Commodore.
SPOCK: This machine seems to have a programmed defensive sphere. Any energy source entering that field is subject to attack.

Another implicit hyperlight-impulse proof. Enterprise entered the “defensive sphere” (whose radius must exceed a parsec, per her sensor range), whereupon the Machine turned and engaged. Constellation is now attempting to depart the Machine’s sphere of attention.
​

SPOCK: Warp drive and deflectors will be out for a solar day. Repairs proceeding on transporter and communications.
SULU: It's closing with us again, sir.
DECKER: Maintain speed and distance.
SULU: It's sucking in space rubble from those destroyed planets. Refueling itself.
SPOCK: We can maintain this speed for only seven hours before we exhaust our fuel, but it can refuel itself indefinitely.

Impulse-powered duration (“depending on the speed involved”) is cited as about a month in Making of ‘Star Trek.’ Dilithium-less power duration (“on batteries”) is cited as days in “Mudd’s Women.” We don’t know what’s “powering” the impulse drive at this point…but we do know a fusion explosion of 97.835 megatons will result if a starship impulse engine is overloaded. It seems reasonable then to assume Enterprise to be at this point consuming “fuel” (hydrogen for fusion) at an enormous rate, to maintain what is (for impulse) an enormous speed. After all, were she sublight on impulse, wouldn’t the next lines be:
​

DECKER: But Spock, can’t we coast?

SPOCK: My error, Commodore.

• “Wrath of Khan”

SULU: Course plotted for Regula I, Admiral.
KIRK: Engage warp engines.
SAAVIK: Prepare for warp speed.
SULU: Ready, sir.
KIRK: I know that none of you were expecting this. I'm sorry. I'm gonna have you to ask you to grow up a little sooner than you expected. Warp five.
SULU: So much for the little training cruise.
Reliant bridge scene omitted]
[Enterprise bridge]
UHURA: Space Station Regula I. Please come in. Doctor Marcus. Please respond. This is Enterprise call... It's no use, there's no response from Regula I.
SPOCK: But no longer jammed?
UHURA: No sir. No nothing!
SPOCK: There are two possibilities. They are unable to respond. They are unwilling to respond.
KIRK: How far?
SPOCK: Twelve hours and forty-three minutes, present speed.
KIRK: Give up Genesis, she said. What in God's name does that mean? Give it up to whom?
SPOCK: It might help my analysis if I knew what Genesis was beyond the biblical reference.
KIRK: Uhura, have Doctor McCoy to join us in my quarters.
UHURA (OC): Aye sir.
KIRK: Mister Saavik, you have the con.
[Kirk's quarters]
McCOY: Well, I've got the sick bay ready. Now will someone please tell me what's going on?

Genesis briefing begins. Note that NO delay, and very little off-screen time has elapsed. Did Enterprise drop from warp on assume a twelve hour forty-three minute sublight approach? Ridiculous!
​

SAAVIK (on intercom): Bridge to Admiral Kirk. Admiral, sensors indicate a vessel in our area, closing fast.
KIRK: What do you make of her?
SAAVIK (on intercom): It's one of ours, Admiral. ...It's Reliant.
KIRK: Reliant!
This concludes the Genesis briefing, just prior to which 12:43 ETA cited.
[Enterprise bridge]
KIRK: Try the emergency channels. ...Picture, Mister Saavik.
[Reliant bridge]
KHAN: Slow to one-half impulse power. Let's be friends.
HELMSMAN: Slowing to one-half impulse power.
[Enterprise bridge]
SULU: Reliant in our section, this Quadrant, sir, and slowing.

However the hell big a “Quadrant” (or for that matter, a “section”) is, it’s sure as hell not definable as a sublight-traversable distance…is it?
​

[battle]

Peter death scene, concluding with:
​

SPOCK (on intercom): Engine room reports auxiliary power restored. We can proceed at impulse power.
KIRK: Best speed to Regula I. Kirk out.
McCOY: I'm sorry, Scotty.

So…they were 12:43 out at warp five…dropped to one-half impulse…fought at nearly point-blank range (presumably from relative dead stop positions)…proceeded at “best speed,” on impulse, to Regula…and arrived before onset of rigor among people killed before all this occurred.
“In humans it commences after about 3 hours, reaches maximum stiffness after 12 hours…”
​

If anything, “best speed” had to have been faster than warp five! How much faster? Well, maybe--

• “Conspiracy”

RIKER: Increase to warp six.
LAFORGE: Aye sir. Full impulse.

One might well wonder, how in HELL did these lines make it onto the air? Were Rick Sternbach and the Okudas’ technical advisements overridden? Was every actor in the scene brain dead that day of shooting? Or could it perhaps be that cast and crew alike decided to let air (on 9 May 1988) something they’d come to realize…even desire…that they knew well the fanboys would explode in anger over? As perhaps occurred once more on the release date of 6 December 1991:
​

“Star Trek VI”
Stardate 9521.6, Captain's log, U.S.S. Excelsior. Hikaru Sulu commanding. After three years I've concluded my first assignment as master of this vessel, cataloguing gaseous planetary anomalies in the Beta Quadrant. We're heading home under full impulse power. I am pleased to report that ship and crew have functioned well.
[Excelsior bridge]
SULU: According to this we've completed our exploration of the entire sector.
(the ship begins to shudder and Sulu's teacup rattles off his table and breaks on the floor)
VALTANE: I have an energy wave from two hundred and forty degrees mark six port.
SULU: Visual! My ...God. ...Shields!
(an energy wave hits the ship throwing the crew about)
LOJUR (OC): Captain, she's not answering her helm.
SULU: Starboard thrusters. Turn her into the wave!
LOJUR: Aye.
SULU: Quarter impulse power! ...Damage report.

Per Sulu, “We’re heading home under full impulse.” Pretty explicit. Not “at full impulse, about to start for home.” UNDER full impulse. Note too what Sulu does NOT say:
​

“Visual! My…God! FULL EMERGENCY WARP AFT!!!”

Be the first thing I’D think to say, I were in his shoes…unless “full impulse” is…well…pretty damn fast.
​

• “The Mind’s Eye”

Georgi is en route to Risa in a shuttlepod. A shuttlePOD. Nacelled, but warp drive-less.
​

As to the matter of the 1701-D’s incontrovertibly hyperlight-capable saucer having unseen (emergency-deployable?), unmentioned (on air or in any tech source) warp engines, warp engines…doesn’t the above, via Occam’s Razor, suggest…ahem…another explanation?
Timo, it took me about 3 hours to put this reply together. I soldiered on, despite a computer crash and the inescapable feeling, as sensible as arguing evolution with a fundamentalist. I’m open to argument, even refutation (you think I “like” a hyperlight-capable impulse?). I’m not a troll, a child, or a novice. What I am is a stringent and honest student of what seems to me to be “series reality.” So please, do me the respect of offering something more than the flailing apologism of your previous post, ‘kay?