Getting Rocket Plumes Correct In Scifi

[Spacescifi]

 

Usually in just about any media scifi one will see glowy pointy long plumes flowing from advanced futuristic rockets in space.

 

Is this realistic at all? Especially with torchdrive efficiencies?

 

I tend to think not.

For example, in one scifi online comic I like to read, alien rocketships accelerate at 30g max (thanks to inertia dampeners alien crew is not blue wall stains).

The author says the alien rocketships use a special substitute fuel/propellant just as energetic as antimatter without the same level of handeling fuss as antimatter.

In the comic the alien rocket vessels blow long glowy plume exhaust....no doubt in part because it is visually appealing to the reader. And I also learned (from the author no less) that a typical vessel of this sort can do 30g for 100 hours before it runs out of fuel/propellant.

 

Main Question: That cannot be right? Right? I mean a glowy plume implies an awful lot of mass flow right? And these engines are obviously uber efficient. As it takes them 100 hours at a whopping 30g constant thrust to actually exhaust it's fuel supply. These vessels are big, but not so big that the size would justify such mass flow

The author takes pains to be accurate with physics where possible without compromising the fiction, but I think he may have goofed on this detail...or maybe it just did not look cool enough. I dunno.

 

Like if they used ships the size of the death star then a glowing plume would make sense....since you need that kind of mass flow to move something so massive efficiently.

 

I won't tell him to redo his illustrations because his comic is still fun to read, but I just have a suspicion that any scifi vessel with torchship efficiencies at a constant 30g is insane fuel efficiency and will have a lightbulb looking nozzle....little to no exhaust seen.

 

Am I right? Or wrong?

 

And does this not apply to ALL torchships that are uber efficient with uber thrust?

 

How they would appear as a plume and nozzle?

Edited June 5, 2021 by Spacescifi

[SOXBLOX]

3 hours ago, Spacescifi said:

For example, in one scifi online comic I like to read, alien rocketships accelerate at 30g max (thanks to inertia dampeners alien crew is not blue wall stains).

It wouldn't be Outsider, would it?

And you're right. Visual plumes don't really jive with high efficiency engines. Or any engines, really. The exhaust expands super quickly. Close to the nozzle, you can see it. Say, 1 km behind the nozzle? Nope.

[kerbiloid]

The antimatter plume is of gamma-rays color. Same bright.

[Spacescifi]

9 hours ago, SOXBLOX said:

It wouldn't be Outsider, would it?

And you're right. Visual plumes don't really jive with high efficiency engines. Or any engines, really. The exhaust expands super quickly. Close to the nozzle, you can see it. Say, 1 km behind the nozzle? Nope.

 

That's the one...the thing is, I doubt you would see much plume even close to the nozzle.

 

For example, let's say we use the uber-efficient engines....how much glow you really see depends on mass flow, annd in order to have high mass flow enough to see it then you need a LOT of propellant to burn at 30g in 100 hours.

Let's say you have a thousand tons of this super propellant (same as IRL Spacex starship) that would take up a lot more space inside vessels than depicted, unless the stuff is dense as liquid uranium.

Even then, if one does the math and divides a thousand tons by 100 hours one will see that these super engines only burn ten tons of this super fuel every hour.

Which means when looking at the nozzle anything you see coming out would be a lot less than ten tons.

Even the shuttles have the long glowy plumes, and I woild like to think they lack the superefficiency of the ships but I doubt that.

 

Pointy rocket plumes in space seem strange due to a lack of atmosphere, but then again I sulppose with thrust this insane that would not matter.

 

At best. I think. wispy blue plume may be in order, barely visible and throughly transparent.

No...maybe purple since it's fuel must be superdense, but still transparent.

[SOXBLOX]

Oops. I meant with modern chemical engines. I did say high efficiency types would have no plume. My bad; I didn't clarify.

[Spacescifi]

9 hours ago, kerbiloid said:

The antimatter plume is of gamma-rays color. Same bright.

 

Nice....invisible then, except for the nozzle glow.

Likely seeing some massive regeneratuve nozzle cooling here.

11 minutes ago, SOXBLOX said:

Oops. I meant with modern chemical engines. I did say high efficiency types would have no plume. My bad; I didn't clarify.

 

Well then......I guess I don't need to pester him, I just love to see how scifi would REALLY look

 

If one still wanted the long glowy plumes then he would need much larger vessels to increase mass flow required of the fuel.

 

At any rate his shuttles would not have visible plumes anyway if they have the same efficiency.

 

 

It's not just outsider, everything from Elite dangerous and on does this.

 

Ironically Babylon 5's human battleships got it right in the battle for Earth.

 

When Sheridan said ramming speed his ship's nozzles glowed but lacked any long glowy plumes. I mean they were very short and somewhat transparent yet glowy, but they still don't come any where near outsider efficiencies!

 

 

Edited June 5, 2021 by Spacescifi

[SpaceFace545]

Thread a day