Shields used to create aerodynamic bubble for ships in atmosphere.

[Santaman]

The fusion reactors will have to expell the fusion product, mainly helium and probably they use it also to get rid of a lot of waste heat, I guess after a while there will be too much plasma and it needs to be vented, fusion reactors are rather iffy, anything upsetting the balance inside them will make them stall.

 

[XCV330]

Why bother when you have engines that are as powerful as what is mounted on starships/shuttles, to make a real life example, the MiG 25 also is a flying nickel alloy brick and yet it is one of the fastest aircraft ever made because it has enormous engines.

On ICBM's they use a so called aerospike which reduces drag.
https://en.wikipedia.org/wiki/Drag-reducing_aerospike

anecdotal but I once heard a jet mechanic tell a story about IAI Kfir fighter that had lost most of a wing from a SAM. The pilot managed to land the thing missing control services and most of a wing practically on jet thrust alone. Since they didn't have vectored thrust i am not sure how reliable that is, but its fun to think of.

I like the idea of force field aerodynamics too. Good thread.

 

[Kamen Rider Blade]

Venting of impulse plasma is confirmed. Use of said plasma as a Newtonian propulsive jet is not, and indeed is heavily contradicted by

1) impulse engine "nozzles"/vents pointing whichever way, including at the structures of the ship itself
2) impulse vents glowing all the time, regardless of the ship's state of motion
3) nobody actually getting burned or blasted away by a jet coming from the impulse engine.

But while warp engines expel plasma only in emergencies (it supposedly forming a closed loop in normal operations, either flowing around or then just sitting there so that warp energies can flow through it), impulse plasma seems to be vented basically all the time. Which I guess is the interesting bit here. Is the venting necessary for providing motion? Or for keeping the engine from overheating or blowing up? Do all engines turn the venting into a propulsive asset, or do just some, or none?

Perhaps worth mentioning is that the glow from the (impulse?) engine of the BoP in "Search for Spock" does not significantly die down when the ship lands on Vulcan, yet our heroes readily exit through a ramp right below this glowing doodad. Perhaps even at its worst, an impulse engine vent puffs out truly minuscule amounts of hot helium, not enough to make the air shimmer or the heroes' hair get messed up? Or perhaps idle and full thrust modes just happen to be visually identical for reason X.

Timo Saloniemi

http://memory-alpha.wikia.com/wiki/Impulse_drive
In Federation starships, the impulse drive was essentially an augmented fusion rocket, usually consisting of one or more fusion reactors, a driver coil assembly, and a vectored thrust nozzle to direct the plasma exhaust. The fusion reaction generated a highly energized plasma. This plasma, ("electro-plasma") could be employed for propulsion, or could be diverted through the EPS to the power transfer grid, via EPS conduits, so as to supply other systems. The accelerated plasma was passed through the driver coils, thereby generating a subspace field which improved the propulsive effect.

http://memory-beta.wikia.com/wiki/Impulse_engine
An impulse engine (a colloquialization of internally metered pulse drive) was a nuclear fusion based propulsion system used primarily for sublight speeds. Impulse engines were first used by Humans in the 21st century aboard the Nomad unmanned probe and then on the manned USS Lewis & Clark, the first ship to visit Saturn. (TOS novel: The Rings of Time) This technology was later used by the United Earth, and later the Federation. (TOS novel: Final Frontier; ENT novelization: Broken Bow) Each impulse engine consisted of one or more nuclear fusion reactors, a series of subspace field coils, and a vectored thrust nozzle to direct the plasma exhaust; which produced a high energy plasma which was vented out of the thrust nozzles to propel the starship. (ST reference: USS Enterprise Owners' Workshop Manual) The deuterium based fusion reaction of the impulse drive also would serve as a secondary power system for a starship and was utilized for powering internal systems. (TNG reference: Star Trek: The Next Generation Technical Manual) In the event of an emergency while at warp, the impulse engines could also be utilized to temporarily generate a Warp field to maintain warp speed for the vessel or the primary hull in the event of Saucer separation. (ST reference: USS Enterprise Owners' Workshop Manual)

https://en.wikipedia.org/wiki/Impulse_drive
In the fictional Star Trek universe, the impulse drive is the method of propulsion that starships and other spacecraft use when they are travelling below the speed of light.[1] Typically powered by deuterium fusion reactors, impulse engines let ships travel interplanetary distances readily. For example, Starfleet Academy cadets use impulse engines when flying from Earth to Saturn and back.[citation needed] Unlike the warp engines, impulse engines work on principles used in today's rocketry, throwing mass out the back as fast as possible to drive you forward.

 

[Timo]

It's a bit disappointing to see such baloney perpetuated by three wikis in a row... But not surprising.

Suffice to say that the claim is baseless, as far as the known Star Trek universe is concerned. Although it furthermore is contrary to Star Trek pseudofact, whether that amounts to anything.

Timo Saloniemi

 

[Santaman]

Okay.. so what kind of an exhaust plume would it generate to accelerate a Galaxy class ship to its usual speed as fast as we see on screen? We'll forget the amount of fuel etc for this.. think the ship has a mass of 5 million tons IIRC

 

[Timo]

I guess we could establish an upper limit on the exhaust velocity at, say, lightspeed...

...But, OTOH, we could decide the ship's inertial mass during acceleration is exactly five and a half grams, whereas the exhaust plume masses fifty tons for each gram of fuel drawn from the tanks. It's Star Trek, after all: they can use Newtonian rocketry for going interstellar if they really wish to.

Timo Saloniemi

 

[Santaman]

Ha! yeah.. that sounds like Star Trek..

 

[Kamen Rider Blade]

You remember in DS9's first episode when they had to move DS9 to next to the opening of the Worm Hole.
O'Brien created a SubSpace Field that lowered the stations effective mass which let it be moved easily towards the location

I bet you that O'Brien picked up that idea from somewhere that was already in use, probably normal Federation StarShips which allows them that phenomenal manueverability.

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[CorporalCaptain]

You remember in DS9's first episode when they had to move DS9 to next to the opening of the Worm Hole.
O'Brien created a SubSpace Field that lowered the stations effective mass which let it be moved easily towards the location

I bet you that O'Brien picked up that idea from somewhere that was already in use, probably normal Federation StarShips which allows them that phenomenal manueverability.

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There's also that TNG episode where Q loses his powers, and says something to Geordi that makes him think of something similar to try to move an asteroidal moon with the ship's tractor beam. "Deja Q" [http://www.chakoteya.net/NextGen/161.htm]:

Q: This is obviously the result of a large celestial object passing through at near right angles to the plane of the star system. Probably a black hole.
DATA: Can you recommend a way to counter the effect?
Q: Simple. Change the gravitational constant of the universe.
LAFORGE: What?
Q: Change the gravitational constant of the universe, thereby altering the mass of the asteroid.
LAFORGE: Redefine gravity? How am I supposed to do that?
Q: You just do it. Where's that Doctor, anyway?
DATA: Geordi is trying to say that changing the gravitational constant of the universe is beyond our capabilities.
Q: Oh. In that case, never mind.
(Crusher enters)
Q: Ah, Doctor Crusher. I see Starfleet has shipped you back into exile.
DATA: Q says he has hurt his back.
CRUSHER: Ah ha. Well, if I didn't see it with my own eyes, I wouldn't believe it. According to this, he has classic back trauma. Muscle spasms.
Q: I've been under a lot of pressure lately. Family problems.
CRUSHER: Well. don't expect too much sympathy from me. You've been a pain in our backside often enough.
Q: Your bedside manner is admirable, Doctor. I'm sure your patients recover quickly just to get away from you.
LAFORGE: You know, this might work. We can't change the gravitational constant of the universe, but if we wrap a low level warp field around that moon, we could reduce its gravitational constant. Make it lighter so we can push it.
Q: Glad I could help. Ow. I think.
CRUSHER: Now what?
Q: There's something wrong with my stomach.​

If that were what was routinely done to up the effectiveness of the impulse drive, it kinda makes one wonder why the chief engineer of a Galaxy-class starship would need any prodding to come up with the idea.

 

[Kamen Rider Blade]

If that were what was routinely done to up the effectiveness of the impulse drive, it kinda makes one wonder why the chief engineer of a Galaxy-class starship would need any prodding to come up with the idea.

Remember in the VOY episode when the AEON comes back in time, and they find out that it has "Hyper-Impulse" drives when it tries to go back to the future?

Maybe it's not routinely done, but a combination of a SubSpace Field / Low Level Warp Field and a Static Warp Shell to deal with Time Dilation when going "> 0.25c" & "< 1.0c" could be what creates "Hyper-Impulse" drives in the future. That's what is going on in my Head Canon.

 

[blssdwlf]

I guess we could establish an upper limit on the exhaust velocity at, say, lightspeed...

...But, OTOH, we could decide the ship's inertial mass during acceleration is exactly five and a half grams, whereas the exhaust plume masses fifty tons for each gram of fuel drawn from the tanks. It's Star Trek, after all: they can use Newtonian rocketry for going interstellar if they really wish to.

Have we ever seen an impulse exhaust plume? There have been mentions of "impulse wake" and "impulse ion trail" and we even see a graphic of impulse ion momentum distribution in "Relics".

 

[Timo]

Trek has been diligent in avoiding Flash Gordon style rocket plumes overall - TNG and DS9 both did one episode showing RCS engine flames, and the Kelvin movies all had rocket action from the undersaucer thingamabobs, but impulse engines have merely been glowing.

...And making space shimmer around them, but warp engine exhaust does this as well in the Kelvin movies.

A mere "tailpipe" would leave trails and the like. Probably only a "rocket" would be likely to give meaningful momentum to the ions, though - that is, momentum that would tell our experts that a starship has been struggling against a tractor beam here.

Timo Saloniemi

 

[Mytran]

If that were what was routinely done to up the effectiveness of the impulse drive, it kinda makes one wonder why the chief engineer of a Galaxy-class starship would need any prodding to come up with the idea.

It's likely that the mass-reducing abilities of the Impulse Engines are just an automatic procedure by the 24th century, which is why Geordi doesn't immediately think about it.

This is the same crew that thought "turn it off and on again" was a revolutionary piece of IT wisdom back in Contagion, after all

 

[Timo]

...Trying to turn, say, a hospital off and on today to get rid of a computer virus would be quite "revolutionary" wisdom today, too!

But yeah, I can see LaForge taking a while to figure out that stuff happening inside his precious engine might be a good way to deal with a moon.

What we might deduce from the exchange is that warp engines don't routinely lower the mass of the starship, as it is the applying of those engines specifically that does not occur to LaForge. Which is a shame - it would be an elegant way indeed to achieve FTL by choosing a negative value for the mass in Einstein's equations!

Timo Saloniemi

 

[Mytran]

Back in the 23rd century it may well have been the job of the nacelles to lower the overall mass of the ship (there's several example of this in TOS and some of the movies)

However, if we believe the TNG-TM then 24th century starships have those nifty compact subspace driver coils installed directly inside the Impulse Engines! So, while nacelles could do the same job, it's not something they are routinely call upon for

 

[Santaman]

So actually when we put everything together impulse engines make absolutely no sense at all..

 

[blssdwlf]

So actually when we put everything together impulse engines make absolutely no sense at all..

LOL, is it worse than warp drive?

 

[blssdwlf]

Back in the 23rd century it may well have been the job of the nacelles to lower the overall mass of the ship (there's several example of this in TOS and some of the movies)

However, if we believe the TNG-TM then 24th century starships have those nifty compact subspace driver coils installed directly inside the Impulse Engines! So, while nacelles could do the same job, it's not something they are routinely call upon for

Well, if you took Laforge's word that impulse design hasn't changed for 200 years you could argue that TNG's older ships used the same magic with the exception of what is seen in ENT (they are older than 200 years).

 

[Mytran]

Well, if you took Laforge's word that impulse design hasn't changed for 200 years you could argue that TNG's older ships used the same magic with the exception of what is seen in ENT (they are older than 200 years).

Well, technically he said it hadn't changed "much".
IOW, a reasonably effective drive system made absurdly more efficient through some kind of mass reducer

 

[blssdwlf]

Well, technically he said it hadn't changed "much".
IOW, a reasonably effective drive system made absurdly more efficient through some kind of mass reducer

Oh, I was just coming up with an excuse for not having to account the very rocket thruster-like impulse deck that was ejected in Enterprise's "Shuttlepod One"