Reverse Impulse

Discussion in 'Trek Tech' started by DanGovier, Jun 27, 2018.

  1. uniderth

    uniderth Commodore Commodore

    Joined:
    Jan 27, 2009
    I'm of the opinion that Impulse engines are NOT like rockets. the exhaust vents are just that, they vent exhaust radiation out but do not provide thrust. So you can direction of the impulse engine force without changing the direction the engines are facing.
     
  2. KamenRiderBlade

    KamenRiderBlade Rear Admiral Rear Admiral

    Joined:
    Oct 24, 2012
    Just watch the Final ep of Season 1 of ST: DSC.

    When they jump to the Klingon Cave with the discovery, they use some form of Anti-Grav beams to keep the ship up and stable instead of using landing legs like the USS Voyager.

    To reason out some form of Gravimetric Drive later on down the technological line isn't much of a stretch.
     
  3. Mytran

    Mytran Rear Admiral Rear Admiral

    Joined:
    Aug 5, 2009
    Location:
    North Wales
    Furthermore, Voyager's "landing legs" weren't even really that, at least according to the behind the scenes materials and Rick Sternbach himself (he's on this board sometimes), not least due to the extreme implausibility of balancing a huge starship on those 4 tiny struts.
    Instead, they were listed as "hover pads" which again suggests the use of artificial or anti-gravity tech in play
     
  4. CorporalCaptain

    CorporalCaptain Fleet Admiral Admiral

    Joined:
    Feb 12, 2011
    Location:
    astral plane
    According to the TNG Tech Manual, impulse power uses conventional fusion rockets for thrust, and a space-time driver coil to reduce the inertial mass of the starship and make the level of thrust that can be produced by the rockets more effective.

    Memory Alpha's article on driver coils: http://memory-alpha.wikia.com/wiki/Driver_coil
     
  5. DanGovier

    DanGovier Commander Red Shirt

    Joined:
    Jul 31, 2011
    Location:
    Somerset, UK
    It would seem my assumption about Driver Coils was wrong all along. I always thought they were like particle accelerators, energising the plasma in the impulse engines to increase exhaust velocities. That puts a whole new twist on things.

    Perhaps this explains the glowie dome on the TMP/TWOK era impulse engines! It could very well be the field emitter for the driver coils.
     
  6. Santaman

    Santaman Vice Admiral Admiral

    Joined:
    Jul 27, 2001
    Location:
    Tyre city
    That glowing dome is the deflection crystal, the refit Connie's impulse engines can run on plasma from the warp drive for extra power and to make it possible to use the impulse engines when the fusion reactors are offline.
    To add more confusion, impulse engines are capable of propelling the ship to low warp speeds so I lean even more to them being a specialized type of warp drive of limited power and geared towards low speeds.
     
  7. CorporalCaptain

    CorporalCaptain Fleet Admiral Admiral

    Joined:
    Feb 12, 2011
    Location:
    astral plane
    If by low warp speeds you mean the warp .5 that Kirk ordered in TMP, then a) that's sublight and b) that's just a speed. That's not what's meant by "warp speed" which means a warp factor of at least 1.
     
  8. blssdwlf

    blssdwlf Rear Admiral Rear Admiral

    Joined:
    Feb 26, 2010
    There are examples of low FTL speeds from TOS when stuck on impulse. But... food for thought. In the examples that I can think of when Kirk wanted the ship to travel sublight speeds he specifies "space normal speed" or "sublight factor" or "quarter speed", etc. For him to say "Warp" anything, even "point five" would strongly imply that the impulse drive could be driven into warp speed territory, IMHO.
     
  9. CorporalCaptain

    CorporalCaptain Fleet Admiral Admiral

    Joined:
    Feb 12, 2011
    Location:
    astral plane
    I really don't think so.
     
  10. Mytran

    Mytran Rear Admiral Rear Admiral

    Joined:
    Aug 5, 2009
    Location:
    North Wales
    Captain Kirk really doesn't think so. Otherwise, why would he give the order
    "Impulse power, Mister Sulu. Ahead, warp point five"
    The fact that Sulu understands the order shows that you can apply the term "warp" to speeds below 186,000 mps

    Granted, ½ lightspeed is a deal swifter than typical sublight velocities in the show. But maybe that's why Kirk went the extra mile and specified "warp" in his order, since such a rapid increase in speed would require the assistance of the nacelles to further lower the relative mass of the ship. Going 0.5LS might still be technically possible without use of the warp nacelles, but I'm willing to bet it would take quite a while to accelerate to that velocity! :devil:
     
  11. Timo

    Timo Fleet Admiral Admiral

    Joined:
    Aug 26, 2003
    When Kirk orders warp 0.5 in TMP, one might do well to assume he is in fact testing the warp drive, as recommended by his engineer...

    We do see impulse glow in this context, but that in fact is another item of relevance not mentioned here yet. Namely, impulse engine glow is unrelated to a ship's state of motion. In TNG and ENT, the glow is always on. In TOS, always off (but TOS-R shows without contradiction that there can be glow on occasion). In TOS movies, this varies (but again without regard of the state of motion); in Kelvin, ditto.

    This is consistent with the "tailpipe for the powrplant of a coil drive" interpretation but not much else.

    As for FTL impulse in TOS, I am not convinced of a single occurrence. But young Spock's "rockets" at Talos sound very much like Plan E, the option taken after the system one step down from "impulse" fails to respond and something really primitive is needed. IOW, early weirdness has every excuse to stand out as exceptional...

    Timo Saloniemi
     
  12. Deks

    Deks Vice Admiral Admiral

    Joined:
    Oct 16, 2003
    Well, I don't think Impulse engines are anything like standard rockets.
    For one thing, the Impulse engines allow fast sublight velocities... at least 25% of light speed... higher speeds were also seen and near light speed travel is likely also possible WITHOUT incurring any (or at least large) relativistic effects, especially if subspace manipulation is used (which is what starships frequently do).
    And they are ridiculously efficient.

    As for reverse impulse engines... simple... we hear characters request reverse impulse... but we don't see any visible impulse engines on the front of the hull... perhaps they don't need them and Impulse engines don't really generate exhaust as we understand it (its just that ships frequently travel FORWARD - or they are directed relatively forward considering they are in space).
    Instead, starships use subspace to drop their mass and travel at fast sublight speeds and really large ships like the Sovereign, Galaxy classes and Romulan D'Deridex use this to execute sharp and rapid turns that exhibit maneuverability of a fighter craft... plus I never understood that a fighter craft can turn more rapidly in comparison to a capital ship... both would have a certain amount of mass to move, so the larger the ship, the more powerful 'push' it will need to turn faster - with Trek ships, this isn't an issue since subspace field manipulation drops their mass and voila).

    So I would imagine that impulse engines might generate at least some kind of energy (or field) when they glow and the ship can manipulate it to go forward or backward by using subspace.
    More often than not, we see impulse engines being used to go forward, but if they do go backwards, ships also tend to at some point turn around and then resume at full impulse... this might suggest that going reverse using Impulse could be limiting in terms of velocity or efficiency - though we have no direct data to support this.

    Ships do use thrusters, and probably implement anti-gravity technology of some kind.
    Tom Paris and Harry Kim did manage to outfit the new delta Flyer with impulse thrusters... which indicates to me that thrusters would behave more like chemical rocket propellants perhaps (though no visible exhaust is seen - but that is likely due to budget - we do see them used on the Discovery and nuTrek Enterprise- but, again, they aren't standard thrusters likely.... and probably employ more sophisticated technology to work).
     
  13. blssdwlf

    blssdwlf Rear Admiral Rear Admiral

    Joined:
    Feb 26, 2010
    As I wrote before, these are specifically TOS observations that Impulse could be used at FTL speeds. TNG and later Trek mostly kept to the decision to make Impulse sublight-only although they goofed in "BOBW2".

    There is this interesting bit from "Where No Man Has Gone Before" where the Valiant is out at the edge of the galaxy with only Impulse engines. When swept out of the galaxy 0.5 LY she makes it back in before she self-destructs and leaves behind her ship's recorder. If it were sublight-only impulse engines the esper would have gained god-like powers while the ship was still well outside the barrier. (Assuming the ship could hit 0.9c the trip back would've taken more than half a year.)
    SPOCK: Decoding memory banks. I'll try to interpolate. The Valiant had encountered a magnetic space storm and was being swept in this direction.
    KIRK: The old impulse engines weren't strong enough.
    SPOCK: Swept past this point, about a half light year out of the galaxy, they were thrown clear, turned, and headed back into the galaxy here. I'm not getting it all. The tapes are pretty badly burned. Sounds like the ship had encountered some unknown force. Now, orders, counter orders, repeated urgent requests for information from the ship's computer records for anything concerning ESP in human beings.
    Then we also have Kirk's line about returning to Earth bases in years (but not decades or centuries.)
    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. Earth bases which were only days away are now years in the distance. Our overriding question now is what destroyed the Valiant? They lived through the barrier, just as we have. What happened to them after that?​

    And in "TWOK", the Enterprise while at Warp 5 and a little more than 12 hours away from Regula One the Reliant approaches the Warp 5 Enterprise and attacks at 1/2 impulse (the Enterprise never calls that it is slowing down or matching speeds.) If the Enterprise really limped to Regula 1 at say 0.5c it would taken them over 9 days (if we assume the Enterprise was cruising at a very slow 100c at the time of intercept she would have been >0.01 LY away.)

    Coincidentally, in "The Deadly Years", the Enterprise is intercepted by the "simple impulse" Romulans in the Neutral Zone while the Enterprise was at Warp 5.
     
  14. CorporalCaptain

    CorporalCaptain Fleet Admiral Admiral

    Joined:
    Feb 12, 2011
    Location:
    astral plane
    Look elsewhere in the film:

    "SCOTT (on intercom): We need further warp simulation on the flow sensors.
    KIRK: Engineer, we need warp speed now!
    McCOY: Jim, you're pushing. Your people know their jobs."​

    That's said when the Ent is already traveling at the impulse speed equivalent to warp 0.5. Clearly, Kirk means that he needs the warp drive. I wasn't completely precise, but that's what I meant.

    Of course the warp drive itself can operate at warp speeds less than one.

    "KIRK: Warp drive, Mister Scott. Ahead, warp one, Mister Sulu.
    SULU: Accelerating to warp one, sir. Warp point seven, ...point eight, ...warp one, sir."​

    That's also not what I meant. When Kirk says that he needs "warp speed," he means he needs the warp drive and he needs it to travel at speeds faster than those that can be reached on impulse, you now those warp 1 and above.

    Also, after falling out of the wormhole:

    "DECKER: We're at warp point eight. Engineer, ...report your status there."​

    That's after the main power systems have been overloaded. Doubtful even impulse was operating then. That's just a speed. It doesn't mean that the impulse drive operates like a warp drive (driver coils notwithstanding).

    http://www.chakoteya.net/movies/movie1.html

    A speed relative to what is a more interesting question. The background radiation from the Big Bang, perhaps?

    Oh, and under the classic formula, warp .5 is 1/8 light-speed, not half.
     
  15. KamenRiderBlade

    KamenRiderBlade Rear Admiral Rear Admiral

    Joined:
    Oct 24, 2012
    Remember in the very 1st ep of DS9. Miles O'Brien along with Dax concoted some Deflector Shield arrangement to lower the inertial mass of DS9 to let the thrusters push the station to the worm hole?

    I was thinking that the future "Hyper-Impulse" drives allow normal Impulse drives to safely and consistently be used pass the .25c limit without having to activate the Warp Drives to manipulate subspace and "Warp the ship"

    Part of potentially accomplishing that was the Deflector Shield arrangement that lowered "Inertial Mass" and maybe combining it with a "Static Warp Shell" to protect the vessel from Relativistic effects like Time Dilation.

    This would allow a future vessel to use the full < 1.0c speed range instead of being constantly limited to .25c
     
  16. blssdwlf

    blssdwlf Rear Admiral Rear Admiral

    Joined:
    Feb 26, 2010
    Is there an episode during TOS that limits them to .25c? I'm not aware of any during TOS or even in TNG-verse.

    The classic formula does not seem to match anything in TOS and I am unable to find any examples of the classic formula being mentioned.

    What we do have is time (1.8 hours) and distance (588 million km to 968 million km) traveling from Earth to Jupiter at Warp 0.5 which works out to range from 0.30c to 0.49c (closest vs farthest distance apart) in TMP.
     
  17. KamenRiderBlade

    KamenRiderBlade Rear Admiral Rear Admiral

    Joined:
    Oct 24, 2012
    http://memory-alpha.wikia.com/wiki/Warp_factor
    This lists the formula.

    Everything I've read is that they intentionally limit it to .25c for some reason.

    Mostly to avoid Time Dilation & relativistic effects when in Sub-FTL speeds.
     
  18. blssdwlf

    blssdwlf Rear Admiral Rear Admiral

    Joined:
    Feb 26, 2010
    Well that's good that there isn't anything from an episode since the TOS writers didn't appear to adhere to that at all :)

     
  19. Mytran

    Mytran Rear Admiral Rear Admiral

    Joined:
    Aug 5, 2009
    Location:
    North Wales
    I didn't intend to give the impression that I contested the matter, but for the record I do agree that the term "warp" can be applied to both FTL and STL speeds, depending on the context.

    When Kirk wants FTL speeds he needs to consult the engineer about the "warp drive" specifically, indicating it is a far bigger deal than just pootling around the solar system at STL using the Impulse Drive (although even that requires Scotty to set a certain intermix ration ahead of time).

    My suggestion that certain basic functions of the nacelles can be utilised to help lower the relative mass of the ship is mostly speculation, but it doesn't change the fact that something would need to do it (otherwise the Enterprise would need a ridiculous amount of fuel!). I struck upon using the nacelles because there are certain situations (such as as the end of TWOK or The Paradise Syndrome) where the Impulse Engines seemed OK yet only very slow STL velocities were possible - and the warp drives were knocked out!

    The WF^3 formula for calculating speed was devised well into the series run (doubtless as a reponse to unending fan letters on the subject) but doesn't really hold up to scrutiny very well. As has already been mentioned upthread, the travel time to Jupiter in TMP requires a speed far greater than
    Interestingly enough, the formula suggested in Gene's 1964 series pitch of 0.73 light years an hour does match up to the events of the pilot episode, if nothing else: They explicitly travel 18 light years in "almost 24 hours". 18 LY at 0.73LYph would take around 24½ hours, which allowing for a slightly befuddled captain Pike matches very well.
    Conversely, 18 LY at warp 7 on the WF^3 chart would take 19 days.

    Page 9 of the 1964 series pitch can be read here:
    http://leethomson.myzen.co.uk/Star_Trek/1_Original_Series/Star_Trek_Pitch.pdf
     
    Last edited: Jun 30, 2018
    CorporalCaptain likes this.
  20. XCV330

    XCV330 Premium Member

    Joined:
    Sep 24, 2017
    Location:
    XCV330
    would have been fun to see whatever the reverse-thrust mechanism was fail and the ship just have to do a 180-hardabout and go full impulse to reduce velocity, with the sound effect of Fred Flintstone foot baking.
     
    Mytran likes this.