Show and Tell - NERV-US

[mattinoz]

Now we just need a stock alike big jet plane for getting up past the thicker atmosphere for Pathfinder type launch. 

[Staticalliam7]

On 10/6/2021 at 3:50 AM, KerikBalm said:

On 10/1/2021 at 9:33 PM, Synonym Toast Crunch said:

A good idea would be for the nozzle extension and afterburner mode to not be linked. That is, they don't have to happen together.

Fully agree. I'd like to be able to use the lH2 only version in thicker atmospheres, when high TWR isn't needed, such as on something like Titan. I'd also like to be able to maximize vacuum dV even when using the high TWR afterburner mode, such as when landing on Tylo.

On 10/1/2021 at 9:33 PM, Synonym Toast Crunch said:

The nozzle could automatically extend or retract when you reach a certain atmospheric pressure, while the afterburner would only switch when you manually switch it, or maybe automatically if you're above a certain TWR, but they don't have to happen at the same time.

Well, I think automatic switching would be convenient, like the autoswitching on the rapier... but I can also imagine wanting manual control over it, such as making somewhat shorter vacuum landers: retract the nozzle before touching down.

I can see 2 ways this works:

1) a toggle for the nozzle, and a toggle for the afterburner. The first dynamically changes the atmosphere Isp curve for the engine, the 2nd dynamically changes the overall Isp, thrust, and resource consumption (adding O2). I'm not surehow much of a change to the game engine this would require

2) a multimode engine with 4 modes. If I'm not mistaken, already we can have 3+ engine modes in the game code, even if we only have engines with 2 modes (rapier, panther).

This would be a little awkward to switch between modes, as you'd have 4 modes to cycle through to get the one that you want.

I imagine that mostly during a burn, you'd be going from high TWR and atmo pressure, to low TWR and low atmo pressure, so I'd have the order go:

i) Afterburner, nozzle retracted; ii) Afterburner, nozzle extended; iii) No Afterburner, nozzle extended; iv) No Afterburner, nozzle retracted;

This would allow easy cycling during a burn from the surface of a planet with an atmosphere. In this case, generally you'd want:

1st, high TWR and the nozzle adapted to a high ambient pressure. 2nd High TWR, but an extended nozzle as the rocket climbs. 3rd low TWR and high Isp as you circularize your orbit. The no afterburner, nozzle retracted case isn't needed.

If you want to land on something like Mun, you'd probably not want the afterburner, so you'd go from no burner, extended to no burner, retracted (for touchdown) - this order works again.

But it would be inconvenient when you want to land with the burner on, but the nozzle retracted, supposing you come in with burner on and nozzle extended (such as on Tylo), you need to press the cycle button 3 times rapidly to get to the burner+retracted mode for landing.

Similarly, taking off from Mun with  the mode initially being: no-burner, retracted  - if you want to switch to no burner, extended, you'd cut the engine, and have to cycle 3 times to get to the mode you want...

So if we can't just have independent toggles for the burner and the nozzle, 4 modes to cycle through would be a bit annoying.

When I saw this, I immediately thought of a different solution. Add 2 sliders: Afterburner throttle (restricts the amount of afterburner LOX flowing), and a Nozzle slider to extend and retract the nozzle

 

[A Generic Kerbal]

4 hours ago, Staticalliam7 said:

When I saw this, I immediately thought of a different solution. Add 2 sliders: Afterburner throttle (restricts the amount of afterburner LOX flowing), and a Nozzle slider to extend and retract the nozzle

 

Maybe not a slider, but a switch

But overall, I like the idea

[Osirin]

On 10/1/2021 at 12:38 PM, Yellowburn10 said:

Man, this means we could potentially have SSTOs needing only one engine for all of it's tasks. I'm just all the more excited to get to try this stuff out!

Wow, Matt Lowne is gonna have a field day with that idea once KSP comes out in 2023.

[TheOrios]

Oh wow that look incredible! can't wait to stick 500 to a rocket and see if i can get too another star lol

[Abel Military Services]

@Nertea this engine is from Kerbal Atomics, isn't it? 

[Astroneer08]

Will this have gimbal? I bet the plume looks awesome!

[Astroneer08]

Could you make a xenon engine with afterburner?

[Deddly]

3 hours ago, Astroneer08 said:

Could you make a xenon engine with afterburner?

I'm no expert, but I'm having difficulty imagining how an afterburner would work on a xenon engine. Can you elaborate? 

[Strawberry]

You can technically react xenon with fluorine and produce energy (though this is very difficult to do and produces very little energy), however I assume what they mean is a xenon engine with a higher thrust low efficiency mode. You can get this with a plasma engine through varying how much you heat up the gas (See VASIMR)

Edited November 16, 2022 by Strawberry

[Astroneer08]

On 11/16/2022 at 5:05 PM, Deddly said:

I'm no expert, but I'm having difficulty imagining how an afterburner would work on a xenon engine. Can you elaborate? 

Maybe have a special fuel and sacrifice efficiency for better thrust. Maybe a bigger engine or rotating panel that deploys another engine with a stronger TWR

Just now, Astroneer08 said:

Maybe have a special fuel and sacrifice efficiency for better thrust. Maybe a bigger engine or rotating panel that deploys another engine with a stronger TWR

Although my idea sounds a little silly

[Bej Kerman]

19 hours ago, Astroneer08 said:

On 11/16/2022 at 10:05 PM, Deddly said:

I'm no expert, but I'm having difficulty imagining how an afterburner would work on a xenon engine. Can you elaborate? 

Maybe have a special fuel and sacrifice efficiency for better thrust. Maybe a bigger engine or rotating panel that deploys another engine with a stronger TWR

19 hours ago, Astroneer08 said:

Maybe have a special fuel and sacrifice efficiency for better thrust. Maybe a bigger engine or rotating panel that deploys another engine with a stronger TWR

Although my idea sounds a little silly

If your idea has no scientific basis then it won't end up in KSP 2.

[t_v]

20 hours ago, Astroneer08 said:

Maybe have a special fuel and sacrifice efficiency for better thrust. Maybe a bigger engine or rotating panel that deploys another engine with a stronger TWR

If you don't care about shooting a couple hundred kilograms of Mercury into the atmosphere, it is a higher thrust alternative to Xenon as it is a more massive particle and more easily ionized. Getting individual atoms to shoot out, or efficiently ionizing clumps of atoms, might be a minor challenge but can probably be worked out by having an exposed surface which the ionizing field propels atoms off of. A larger engine gives more space for the particles to be accelerated, thus giving higher thrust. And if you have another engine, or a larger engine for that matter, you probably don't want to add mass to have it rotate around, and instead have it be the default engine or build the efficient engine around the powerful one.

[Pat20999]

On 10/1/2021 at 6:13 PM, StarSlay3r said:

 

The engine has 2 modes:
Low-thrust, high-ISP mode that uses liquid hydrogen in the same way that the NERV does.
High-thrust, low-ISP mode that burns both liquid hydrogen and oxidizer (think of this as an afterburner that dumps LOX into the nozzle itself for extra kick)

In low-thrust mode, a large vacuum-rated nozzle telescopes downward, extending the overall nozzle length. In high-thrust mode, the nozzle is short.

Does this mean hydrolox?