DumbDumb2007
Commander
Apart from the Starship Voyager how do Impulse Engines in reverse work ? Is there a magnetic filed they use to make the laws of pohysics alter so the thrust pulls the ship backwards ?
Impulse engines in reverse ; How do they work ?
- Thread starter DumbDumb2007
- Start date
Nah- they just put in "R".
Maybe they have shudders on the rear impulse and re-direct the energy out of what ever ports they need for reverse...
Maybe they have shudders on the rear impulse and re-direct the energy out of what ever ports they need for reverse...
If impulse engines are field based, the shape of the field could determine the direction of motion.
In a recent thread, a "kitchen rudder" type forcefield was suggested as a possible thrust reverser for a rocket thrust based impulse drive.
That sort of exhaust vectoring would help explain why Starfleet likes thin saucers and necks: the impulse engines, if mounted at the trailing edges of those saucers and necks, would be able to fire forward past such structures.
Doesn't really work all that well for the thick Galaxy neck. But the exhaust reverser fields might have rather weird shapes to cope. One would think that the more complex the reverser "chute", the more losses in the process, but this need not be true, either: the forcefields might in essence act like perfectly "reflective" paths for the exhaust, transferring momentum efficiently and in the desired manner regardless of how many impacts the exhaust particles make with the "walls".
I'd really like for the impulse engines to be a mixture of field drive and conventional rocket, to explain all the confusing and even conflicting references to them on screen and in backstage material. If nothing else, the Newtonian functionality would be a nice backup if the field drive fails. OTOH, the thrust reversing might be a secondary application of the drive field. Say, the engine grabs the exhaust and uses subspace fields to play tricks with exhaust mass, ship mass, and the coupling between those two, making the rocket much more efficient than Newton would allow. But the same field could grab and twist the exhaust for steering purposes.
Then again, some ships like the E-B and E-E seem to have a series of slots on their impulse boxes that might be mechanical thrust reversers. A backup for a backup?
Timo Saloniemi
Doesn't really work all that well for the thick Galaxy neck. But the exhaust reverser fields might have rather weird shapes to cope. One would think that the more complex the reverser "chute", the more losses in the process, but this need not be true, either: the forcefields might in essence act like perfectly "reflective" paths for the exhaust, transferring momentum efficiently and in the desired manner regardless of how many impacts the exhaust particles make with the "walls".
I'd really like for the impulse engines to be a mixture of field drive and conventional rocket, to explain all the confusing and even conflicting references to them on screen and in backstage material. If nothing else, the Newtonian functionality would be a nice backup if the field drive fails. OTOH, the thrust reversing might be a secondary application of the drive field. Say, the engine grabs the exhaust and uses subspace fields to play tricks with exhaust mass, ship mass, and the coupling between those two, making the rocket much more efficient than Newton would allow. But the same field could grab and twist the exhaust for steering purposes.
Then again, some ships like the E-B and E-E seem to have a series of slots on their impulse boxes that might be mechanical thrust reversers. A backup for a backup?
Timo Saloniemi
GodThingFormerly
A Different Kind of Asshole
Why can't they be ordinary Newtonian rockets on the NCC-1701/Refit and mixed-mode devices on the Enterprise-D and later Starfleet space vehicles? After all, the ST:TNG-TM by Sternbach & Okuda specifically invokes a field generation mechanism for the E-D's impulse engines.
I think that would be somewhat overdoing it, considering if the impulse thrust deflector malfunctions a starship can still decelerate the old fashioned way by physically rotating 180 degrees around the y- or z-axes so as to orient its impulse nozzles in the direction of flight.
TGT
I'm just not sure "ordinary" would cut it as regards NCC-1701 performance. Even if the reaction mass is superdense, its inertia has to be masked somehow for the rocket equation to make sense.
And while the TNG Tech Man introduces a mass reduction field system for the impulse engines of E-D (and also E-C), I'd like to argue that such a system has always been part and parcel of the impressive sublight performance of starships. In the E-B and E-A, it simply happened to be a separate system, that is, not built into the impulse engines. Say, it could have been the blue glowy dome adjoining the impulse drives there, and in NX-01. Kirk's original ship would have had something more like the E-C/E-D system.
Agreed. Then again, those ships do have the strange slots which beg for a treksplanation. And the Scimitar of ST:NEM infamy had a mechanical reverse thrust system visually remniscent of the Leonov one in 2010. The general illogic of some Trek incarnations aside, such a construct would suggest there is some merit to providing at least certain types of starship with the ability to move ass first at full sublight clip.
Timo Saloniemi
GodThingFormerly
A Different Kind of Asshole
Sure, but as I proposed here why cram more junk into the impulse engine assembly when the warp drive can provide the same functionality with reduced mass, volume and complexity penalties?
Yes, it was built into the warp nacelles.
The blue glowy dome was described as the "impulse deflection crystal" by Andrew Probert, and I already rationalized - to my own satisfaction, anyway - its operation in this post.
Kindly visualize the following: The Berman-Eaves Aerospace Corporation unethically lowballs its bid proposal for Starfleet's Excelsior Class Modernization Program, gets the contract with the assistance of a bunch of Deltan and Orion hookers specializing in interspecies sapphic doubles sent to the dachas of the relevant Starfleet admirals while their spouses are away playing bridge, and then in order to make a profit manages to come up with the cheapest, shittiest imaginable engineering "solutions" capable of meeting - only on paper - the updated performance requirements. This was partially achieved by scrounging up some slotted nozzle louvres fabricated decades earlier for the Enterprise Class and then cutting and glueing them together in order to cover the, um, megapulse engines bolted onto the primary hull right in front of the warp nacelles so as to provide an ingenious (BEAC patent pending) range-boosting self-refueling capability for no extra charge. Conundrum solved.
The original NCC-1701 was capable of doing precisely that a century earlier when escaping from the increasingly radioactive alien buoy in The Corbomite Maneuver.
TGT
GodThingFormerly
A Different Kind of Asshole
Source, pliz?
TGT
One of the old novels had impulse as Inertially Metered Pulse, AFAIR.
Newtonian rockets will not move a starship very fast without the inertial mass of the ship being very low. One might ask if the impulse drive system has changed much from the NX-01 to E-E in its capacities.
Newtonian rockets will not move a starship very fast without the inertial mass of the ship being very low. One might ask if the impulse drive system has changed much from the NX-01 to E-E in its capacities.
Well, if LaForge is to be trusted in "Relics", it hasn't. And since LaForge speaks of 200 years of not much progress, NX-01 and her contemporaries would indeed be nice candidates for a breakthrough in this respect.
Indeed. Which is why I like the synergy between the old Probert terminology for the blue dome thingamabob, and the more recent Drexler stuff on what the same thing does on the NX-01. Its function in the latter case is said to be manipulation of the warp field, and indeed such manipulation would benefit the impulse drive by providing the mass-masking feature of a subspace field as described in DS9 "Emissary" and the assorted manuals. Its proximity to the impulse drive in all vessels, but its non-immediate proximity in NX-01, further makes the "indirect" role in impulse drive plausible.
All sorts of nice coincidences can be worked in there. Blue is the color of subspace fields in general (Cherenkov leakage?); the more agile a ship on screen, the more of these domes there, at least per ship size (Miranda two, Defiant eight); etc.
Timo Saloniemi
Yes, it was built into the warp nacelles.
Indeed. Which is why I like the synergy between the old Probert terminology for the blue dome thingamabob, and the more recent Drexler stuff on what the same thing does on the NX-01. Its function in the latter case is said to be manipulation of the warp field, and indeed such manipulation would benefit the impulse drive by providing the mass-masking feature of a subspace field as described in DS9 "Emissary" and the assorted manuals. Its proximity to the impulse drive in all vessels, but its non-immediate proximity in NX-01, further makes the "indirect" role in impulse drive plausible.
All sorts of nice coincidences can be worked in there. Blue is the color of subspace fields in general (Cherenkov leakage?); the more agile a ship on screen, the more of these domes there, at least per ship size (Miranda two, Defiant eight); etc.
Timo Saloniemi
The God Thing said:
Source, pliz?
TGT
It was in Diane Carey's Novel The Final Frontier.
And later:
I would usually say I see no reason to deviate from an original explanation given by the makers of the show -- in this case that impulse is exactly what the name connotes -- a Newtonian thruster. My only qualms over this result from my understanding of the mechanics of a space warp. It seems likely to me that the technological evolution to a system that integrates the manipulation of intense gravitational sources with that of an antigravitational source is literally light years beyond the manipulation of either for sublight propulsion. In other words, if you can bend space to create an initial warp, utilize exotic matter or negative energy to prevent the warp from collapsing, and again employ gravity to restore the bent space, you can already do any of the things needed to create a non-Newtonian drive. A civilization on the road to building a space warping drive would pass through various phases of non-Newtonian sublight drives before they would achieve the more difficult act of balancing these various manipulations to create an effectively FTL space warp.
Enterprise might have employed a conventional drive of some sort if these other drives turn out to be dangerous to use in certain situations. Perhaps, for example, in the vicinity of certain unstable stellar phenomenon, or an inhabited planet. But in free space? I have a hard time rationalizing a purely Newtonian drive when the ship must already be able to do so much more.
Enterprise might have employed a conventional drive of some sort if these other drives turn out to be dangerous to use in certain situations. Perhaps, for example, in the vicinity of certain unstable stellar phenomenon, or an inhabited planet. But in free space? I have a hard time rationalizing a purely Newtonian drive when the ship must already be able to do so much more.
As I think TGT has pointed out before, if one wishes to preserve all aspects of sense and original understanding, a fine interpretation would be to have the impulse engines strictly Newtonian, and have the nacelles used for more than effectively FTL speed. The nacelles can use either their supergravity and/or negative energy to move STL as well, even to the point of inching the ship backwards.
The problem with impulse drives being Newtonian in nature is that the ships simply don't carry enough fuel. When ships are cruising around, the impulse engines are shown or implied to be in a constant state of thrust, if thrust is the right word. Always glowing. They'd need fuel tanks the size of the Death Star to achieve that kind of crap with the speeds and maneuvers they pull.
Also, there's the problem of mass distribution. The way they're positioned, those suckers would cause the average starship to tumble end-over-end if they were pumping out millions of pounds of deuterium fusion thrust.
Its possible that the impulse drive can "afterburn" and jet out some fusion plasma for emergency thrust, but I would guess this would be used only as a last resort, like with the shuttle in "The Galileo Seven".
Also, there's the problem of mass distribution. The way they're positioned, those suckers would cause the average starship to tumble end-over-end if they were pumping out millions of pounds of deuterium fusion thrust.
Its possible that the impulse drive can "afterburn" and jet out some fusion plasma for emergency thrust, but I would guess this would be used only as a last resort, like with the shuttle in "The Galileo Seven".
It may be the case that the fusion "waste" products are vented to provide more impulse, but how much could that contribute without a greatly reduced ship's mass.
Juan rightly pointed out the problem with such a exhaust not going though the center of mass.
Juan rightly pointed out the problem with such a exhaust not going though the center of mass.
The fuel would be carried in a superdense form, and to some extent be replenishable. And at least my interpretation is that the Newtonian impulse would only be used when it is inadvisable to use the exotic drive -- which would be either a supergravity or antigravity component of the warp drive.
Also, it might be possible that the two might be used in tandem. Perhaps that is why the domes on the front of the nacelles are always spinning away. If they are containment for a supergravity component -- multiple microsingularities, for example -- then they might be employed for even mundane propulsion tasks like station keeping.
Also, it might be possible that the two might be used in tandem. Perhaps that is why the domes on the front of the nacelles are always spinning away. If they are containment for a supergravity component -- multiple microsingularities, for example -- then they might be employed for even mundane propulsion tasks like station keeping.
