Impluse Drive/Warp Drive Relationship

[N1N]

Hello all, I have a question about what the general consensus would be on the operation of the impulse drive, while at warp. Is there some kind of hot standby mode for the impulse engines while at warp?
Also when making a significant journey using the warp drive(12hrs+) would it be better to just shut down the impulse drive and maybe get some maintenance time with the engines?

 

[Henoch]

Is there some kind of hot standby mode for the impulse engines while at warp?

Unclear.

From WNMHGB:

SPOCK: Main engines are out, sir. We're on emergency power cells.
...
Captain's log, Star date 1312.9. Ship's condition, heading back on impulse power only. Main engines burned out. The ship's space warp ability gone.
...
MITCHELL: So, er, so, how go the repairs?
KELSO: Well, the main engines are gone, unless we can find some way to re-energise them.
MITCHELL: You'd better check the starboard impulse packs. Those points have about decayed to lead.
KELSO: Oh, yeah, sure, Mitch.
MITCHELL: I'm not joking, Lee! You activate those packs, and you'll blow the whole impulse deck.

From The Naked Time:

SPOCK: Gravity pull increasing. We've shifted to two percent and should stabilise our position.
KIRK: Helmsman, stabilise position.
LESLIE: Helm is not answering to control.
KIRK: Warp us out of here.
LESLIE: No response from engines, sir.
KIRK: Impulse power then. Blast us out of this orbit.
LESLIE: Impulse engines also dead, sir.
SPOCK: Engine room, we need power!
KIRK: Mister Scott, acknowledge. Our controls are dead. Take her.
...
SCOTT: Engineering to Bridge. Try your helm. You'll have enough power to keep her stabilised. Here, let's have a look at that.
SPOCK: Sixteen minutes left, Captain. We've stabilized, but still spiraling down.
...
SCOTT [OC]: Engine room.
KIRK: We've got twelve minutes left. It'll take at least two or three of them to get the engines up to power now.
SCOTT [OC]: Then we'll make it, sir, if all goes right.
...
KIRK: Scotty, we haven't got much time left.
UHURA [OC]: Bridge to Captain.
KIRK: Kirk here.
UHURA [OC]: Entering planet's outer atmosphere, sir.
SCOTT: Captain.
KIRK: What is it?
SCOTT: He's turned the engines off. Completely cold. It will take thirty minutes to regenerate them.
UHURA [OC]: Ship's outer skin is beginning to heat, Captain. Orbit plot shows we have about eight minutes left.
KIRK: Scotty!
SCOTT: I can't change the laws of physics. I've got to have thirty minutes.
Captain's Log, supplemental. The Enterprise, spiraling down out of control. Ship's outer skin heating rapidly due to friction with planet atmosphere.
SCOTT: Maybe twenty two, twenty three minutes.
KIRK: Scotty, we've got six.
SCOTT: Captain, you can't mix matter and antimatter cold. We'd go up in the biggest explosion since
KIRK: We can balance our engines into a controlled implosion.
SCOTT: That's only a theory. It's never been done.
...
SPOCK: Obviously, we were successful. The engines imploded.

From Mudd's Women:

SCOTT: Our last crystal, sir. It's gone.
SULU: Captain Kirk, engineering section reports our entire life-support system is now on batteries.
KIRK: Mister Spock. Miss McHuron, would you mind. Mister Spock, will you contact the miners on Rigel 12? Notify them that we'll need the lithium crystals immediately upon arrival.
...
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.
...
KIRK: I asked for a preorbital course, Mister Farrell.
FARRELL: Preorbital course locked in, sir.
KIRK: That's the last time I'm giving an order twice, gentlemen. We're down to battery power, and we're low on that.
SCOTT: It'll get us to Rigel 12, sir, but it'll be a shaky orbit.
KIRK: Just hang us in long enough to get six crystals, Scotty. That's all we need.
...
SULU: Power curve still dropping, Captain.
FARRELL: We'll make orbit, sir. A temporary one.
KIRK: Lay in. Computer?
SPOCK: We can sustain this orbit for three days, seven hours.
...
SPOCK: Conserving batteries, sir. Half power.
...
KIRK: Sorry, Scotty. How much power do we have left?
SCOTT: About five hours, sir.
Captain's log. Have expended all but forty three minutes of power. Ship's condition, critical.
...
FARRELL: Course plotted and all systems in operation.
SULU: Engines engaged. Helm answering.
FARRELL: Out of orbit, sir.
KIRK: Ahead full.

From The Com M:

SULU: Reducing to warp two, sir.
SPOCK: Tractor beam, Captain. Something's grabbed us, hard.
SULU: Engines overloading, sir.
KIRK: All engines stop.
...
KIRK: Engage, warp factor one.
SULU: Warp factor. There's no response.
KIRK: Switch to impulse.
SULU: All engine systems show dead, and weapon systems.
...
SPOCK: Tractor beam again.
BALOK [OC]: So that you may sustain your gravity and atmosphere, your systems are now open. Escape is impossible since you are being taken under our power to your destination. Any move to escape or destroy this ship will result in the instant destruction of the Enterprise and everyone aboard.
SULU: We're being towed, sir.
...
BAILEY: Captain, he's pulling out a little ahead of us.
SPOCK: He's sneaked power down a bit.
SULU: Our speed is down to point six four of light.
KIRK: I want a right angled course. Shear away from him no matter which way he turns.
BAILEY: Yes, sir.
KIRK: Maximum acceleration when I give the word.
SULU: Yes, sir.
KIRK: Engage.
SULU: It's a strain, Captain. Engines are overloading.
KIRK: More power.
SPOCK: We're superheating. Intermix temperature, seven thousand four hundred degrees. Seven five, seven six, eight thousand degrees. (everything is juddering, the little ship is getting brighter and brighter)
KIRK: Shear away, Mister Bailey.
SPOCK: Two thousand degrees above maximum. Eight four, eight five, eight six. She'll blow soon!
KIRK: Now, Mister Sulu. Impulse power too.
BAILEY: We're breaking free, sir.
KIRK: All engines stop.

From The Doomsday Machine:

SCOTT: Captain, I've checked the engines. The warp drive is a hopeless pile of junk. The impulse engines are not too badly off. We ought to be able to do something with them.
...
KIRK: Well, we just can't stand around while our ship is being attacked. Scotty, you've got to get me some manoeuvering power.
SCOTT: I can't repair warp drive without a spacedock.
KIRK: Then get me impulse power. Half-speed, quarter-speed, anything. If we get this hulk moving, maybe we can do something.
SCOTT: Aye, the impulse engines are still in fair shape. I might coax them.
...
PALMER: (to Spock) Sir, Deck seven reports power failure in main energisers. Implementing emergency procedures. (another hit) Severe casualties reported on decks three and four. Damage control party sealing off inner hull rupture.
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.
DECKER: But don't you understand? We've got to destroy it!
SPOCK: That, sir, is illogical. It is suicide. Attempted suicide would be proof that you are psychologically unfit for command. If you don't veer off, I shall relieve you on that basis.
DECKER: Veer off.
SPOCK: Emergency impulse power.
SULU: We can't break loose!
SPOCK; We need more power.
SULU: We haven't got it. We're being pulled inside.
...
SPOCK: We can maintain this speed for only seven hours before we exhaust our fuel, but it can refuel itself indefinitely.
...
SPOCK: Warp drive out. Deflector shields down. Transporter under repair. We are on emergency impulse power.
KIRK: How long to repair warp drive?
SPOCK [OC]: At least one solar day.
SPOCK: At our present rate of consumption, we'll exhaust our impulse power long before then.
...
KIRK: Mister Sulu, ease us back to minimum headway. Conserve power as much as possible. Lieutenant Palmer, tell Mister Scott to expedite repairs on the warp drive.

From Obsession:

SCOTT: Captain, while we're waiting I've taken the liberty of cleaning the radioactive disposal vent on number two impulse engine, but we'll be ready to leave orbit in under half an hour.
...
CHEKOV: I have a reading on the whatever it is, Captain. Leaving the planet surface, heading into space.
KIRK: All decks, Red Alert. Red alert. Prepare to leave orbit.
SCOTT: Captain, we can't maintain warp eight speed much longer. Pressures are approaching the critical point.
...
CHEKOV: Open hatch on impulse engine number two. Mister Scott was doing an AID clean-up on it.
KIRK: We won't be using the impulse engines. Turn the alarm off.
...
CHEKOV: Five seconds to contact. All hatches and vents secure. All lights on the board show green. Sir! The number two impulse vent! we have a red light!
KIRK: (over Chekov's speech) Lieutenant Uhura, all decks (rest of speech lost under Chekov's increasing volume)
SCOTT: Captain, something's entered through the number two impulse vent.
KIRK: Negative pressure in all ship's vents. Alert all decks.

In The Naked Time, for some reason the Impulse Engines were not an option to break close orbit under that situation with the disintegration of the planet. Only the Warp Engines were strong enough to break orbit and get the ship to a safe distance. All the Engine Room action was about restarting the Warp Engines in time to save the ship. Maybe a hint to Impulse Engines was when Scotty restored stabilization power to the ship, but this could just a easily be just power to some sort of stabilization thrusters. In either case, it is not clear whether the Impulse Engines were needed to be operational with Warp Drive. IMO, probably not.

In Obsession, the Impulse Engines are taken out of service for cleaning the radioactive disposal vent. Scotty says they will be able to leave orbit in under a half an hour, so, it looks like the cleaning operation is somehow holding up leaving orbit. It is unsure based on this situation whether Impulse Engines are needed to break orbit. Later, we find the vent still open suggesting that the impulse engines were not used. Additionally, Kirk says it's okay for the open vent since they won't be using the impulse engines. They must have "warped" out of orbit and chased the cloud.

In WNMHGB, the ship has multiple impulse engines which can be powered, either singularly or combined, by port and starboard power packs. The barrier burned out the Warp Drive and took out (damaged) the Starboard Impulse power packs. It looks like the Impulse Engines were just powered by the port power packs at this point. The power packs have injectors which suggests a fuel is injected into and consumed in the packs for Impulse power.

In Mudd's Women, when the Warp Drive and its associated (di)lithium crystals are out, the Impulse Engines consume a fuel. The Impulse Engines may always consume fuel when being used giving good reason to use them sparingly for propulsion or power generation.

In Elaan of Troyius:

KIRK: Mister Chekov, lay in a course for Troyius. Mister Sulu, impulse drive, speed factor point zero three seven.
SULU: Impulse drive, Captain?
KIRK: Yes, that's correct, Mister Sulu. Sublight factor point zero three seven.
SULU: Aye, aye, sir.
SCOTT: Captain? You'll not be using the warp drive? All the way on impulse? That'll take a great deal of time.
...
MAN: We're only running on impulse engines now. Ordinarily, we use the warp engines exclusively.
SCOTT: Well, I suppose, lassie, that even our impulse engines must seem fast compared to your nuclear propulsion units.
...
SULU [OC]: Captain, the Klingon ship has changed course. It is heading toward us at warp speed.
KIRK: I'm on my way. Battle stations.
KIRK: Phasers stand by.
SULU: Phasers ready, sir.
SPOCK: Their speed is better than warp six, Captain.
KIRK: Mister Chekov, lay in a course to take us out of this star system. If they want to fight, Let's get some manoeuvering room.
CHEKOV: Course computed, sir.
SULU: Laid in, Captain.
KIRK: All right. Ahead warp factor two.
SCOTT [OC]: Captain, the matter-antimatter
KIRK: Belay that order. What is it, Scotty?
SCOTT: The anti-matter pods are rigged to blow up the moment we go into warp drive.
...
SCOTT: I've got bad news, Captain. The entire dilithium crystal converter assembly is fused. No chance of repair.
SCOTT [OC]: It's completely unusable.
KIRK: No chance of restoring warp drive?
SCOTT [OC]: Not without dilithium crystals. We can't even generate enough power to fire our weapons.

My Conclusions:

1. Warp Drive is not needed with Impulse Engines, and Impulse Engines are not needed with Warp Drive. Both systems normally operate independently without the other.
2. While on Impulse, the Warp Engines are usually on warm standby to instantly respond to Warp Drive speeds.
3. When the Warp Drive is out or any of its associated subsystems are out (M/AM reactors and (di)lithium crystal power converter), the ship runs on Impulse Power and Impulse Engines which consumes fuel. It is unclear whether the Impulse Engines can run on the M/AM reactors and (di)lithium crystal power associated with the Warp Drive or on batteries which are the ship's last ditch power source. IMO, probably not for both.
4. The ship typically leaves planet orbits using just Warp Drive. Though most orders to leave orbit are at warp speeds, in Elaan of Troyius, it is implied that they left planet Elas under impulse. Also, in Mudd's Women, Kirk's "ahead full" after breaking orbit sounds like a impulse engine command rather than a warp drive command. Maybe the Warp Engines were not fully warmed up, yet, or, he really wanted to get back on schedule at maximum warp speed...
5. Cold Warp Engines normally take ~30 minutes to start or heat up. It is unclear whether Impulse Engines need time to warm up or not. In The Doomsday Machine, they got impulse power fairly quickly once Scotty repaired the Impulse controls suggesting a short to no warm up time. IMO, the Impulse Engines deliver power when the fuel is turned on.

 

[BK613]

I also like to think that impulse doesn't scale very well, that it is like compound steam engines (without a turbine option to replace them.)

 

[Henoch]

I like the Impulse Engines to fuel injection, internal combustion engines burning gasoline/diesel gas where electrical power can be tapped off them. The direct output of these engines drive space propellers to push/pull against space itself; i.e. it's a speed boat.

I like the Warp Engines to two turbojet jet engines burning jet fuel (aka M/AM fuel) to make thrust, and lots of electrical power can be tapped off them (through the dilithium crystal converter). The direct output of this engine sucks in space (air) and creates a warp in space-time (thrust); i.e. it's a jet plane. Also, lots of energy is needed to control the internal reactions (control surfaces) and power the matter collection systems plus the antimatter fuel facility (pumps). Additionally, more energy is needed for the ship's navigation deflector and sensors (radar and all other electrical systems).

Batteries are still just batteries.

There is no steam boiler down in Engineering to shovel coal into. By Season Two/Three, a third reactor like a steam turbine tied to nuclear reactor in engineering is suggested; it's now a submarine? This third M/AM reactor could be used like an external power supply for warp engine (turbojet) start up, then use its supplementary M/AM output directly for the engines, and/or converted to energy for other engine and ship systems leaving more power for the warp engines to make speed.

By TMP, this reactor in engineer seems to be the only M/AM reactor on the ship. In any case, it is still tied into that same touchy dilithium crystal converter.

 

[BK613]

@Henoch Just using it as an analog to scaling the engines as hull size increased. By the time RMS Titanic has come along, the engines had become enormous (has to do with cylinder size.) I'm suggesting a similar scaling issue with impulse (maybe fuel + the infrastructure needed to deal with fusion temperatures in the millions of degrees.)

Not saying they functioned like that.

 

[publiusr]

Not enough was done with the Surak/ Vulcan shuttle that had combo units