Air-Augmented Engine Eve SSTO challenge

[KerikBalm]

Yes, Eve SSTO is impossible with stock parts, but if we had access to parts like an air augmented rocket engine,

http://en.wikipedia.org/wiki/Air-augmented_rocket

I think Eve would become much more accessible.

So this challenge is to use a specified modded rocket engine to acheive fully reusable SSTO flight from Eve's surface.

Mods allowed: FAR/NEAR, mechjeb, and the specified rocket engine*.

*detailed .cfg at bottom, but important parts are as follows:

Better efficiency than nukes in an atmosphere.

Somewhat similar to the stock turbojet, its TWR is poor at very high, and very low speed.

quick stat summary:

Mass: 2.4

Atmophere ISP curve:

1 atm= 1200 ISP

0.3 atm= 1000 ISP

Vacuum ISP= 360

Velocity curve:

0 m/s = 50% thrust / 175 kN

200 - 800 m/s = 100% thrust / 350kN

2250 m/s and above = 50% thrust / 175 kN

(Ideally, thrust would be 175 kN in a vacuum, and could increase when the engine has more air available, but for now, I'm going with this)

Scoring is simple, highest payload fraction to orbit from "sea" level. If no entries accomplish that, then lowest altitude takeoff that acheives orbit, and if no-one acheives that, highest perapsis.

Rules:

* No infinigliders, avoid use of control surfaces (lets say less than 1 control surface per 5 tons of craft) -thrust vectoring should be sufficient

* No ladder/kraken drives/ other exploits

* The craft must be fully re-usable - it must be ready to go again after docking with an orbital fuel depot, meaning;

- No solid rocket boosters

- The craft must be capable of landing on eve, and then attaining orbit after landing, so include parachutes and struts and fuel for retro burns as neccessary.

* No other mods other than specified, of course, you may hyper edit your craft to orbit around eve to try the descent and then SSTO

Lets see what you can do

There are of course limitations to the KSP engine, but for my simple "simulation" of an air augmented rocket, I'm using the following:

-Duplicated the rapier engine folder, renamed it "AirAugmentEngine"

edited the config file to be as follows:

PART

{

name = AirAugmentEngine

module = Part

author = C. Jenkins and KerikBalm

mesh = rapier.mu

rescaleFactor = 1.5

node_stack_top = 0.0,0.741545,0.0 , 0.0, 1.0, 0.0

node_stack_bottom = 0.0,-0.2048244, 0.0, 0.0, 1.0, 0.0

mass = 2.4

dragModelType = default

maximum_drag = 0.2

minimum_drag = 0.2

angularDrag = 2

crashTolerance = 20

maxTemp = 3600

TechRequired = hypersonicFlight

entryCost = 35000

cost = 3600

category = Propulsion

subcategory = 0

title = Air-Augmented Rocket Engine

manufacturer = C7 Aerospace Division and Rockomax Conglomerate

description = Air-Augmented Rocket Engine is a joint venture between C7 Aerospace and the Rockomax Conglomerate. Designed to fill a gap in the design requirements for extra-kerestrial atmospheric operation, this engine uses extra-kerestrial atmosphere as reaction mass, heating it using standard rocket fuel, to produce more thrust per unit fuel.

attachRules = 1,0,1,1,0

EFFECTS

{

running_closed

{

AUDIO

{

channel = Ship

clip = sound_rocket_spurts

volume = 0.0 0.0

volume = 1.0 1.0

pitch = 0.0 0.2

pitch = 1.0 1.0

loop = true

}

PREFAB_PARTICLE

{

prefabName = fx_smokeTrail_aeroSpike

transformName = smokePoint

emission = 0.0 0.0

emission = 0.05 0.0

emission = 0.075 0.25

emission = 1.0 1.25

speed = 0.0 0.25

speed = 1.0 1.0

localOffset = 0, 0, 1

}

MODEL_MULTI_PARTICLE

{

modelName = Squad/FX/shockExhaust_blue_small

transformName = thrustTransform

emission = 0.0 0.0

emission = 0.05 0.0

emission = 0.075 0.25

emission = 1.0 1.25

speed = 0.0 0.5

speed = 1.0 1.2

}

}

engage

{

AUDIO

{

channel = Ship

clip = sound_vent_soft

volume = 1.0

pitch = 2.0

loop = false

}

}

}

MODULE

{

name = ModuleEnginesFX

engineID = ClosedCycle

runningEffectName = running_closed

thrustVectorTransformName = thrustTransform

exhaustDamage = True

ignitionThreshold = 0.1

minThrust = 0

maxThrust = 350

heatProduction = 650

useVelocityCurve = True

fxOffset = 0, 0, 0.25

PROPELLANT

{

name = LiquidFuel

ratio = 0.9

DrawGauge = True

}

PROPELLANT

{

name = Oxidizer

ratio = 1.1

}

velocityCurve

{

key = 2250 0.5 0 0

key = 800 1 0 0

key = 200 1 0 0

key = 0 0.5 0 0

}

atmosphereCurve

{

key = 0 360

key = 0.3 1000

key = 1 1200

}

}

MODULE

{

name = ModuleAnimateHeat

ThermalAnim = HeatAnimationEmissiveRapier

}

MODULE

{

name = ModuleGimbal

gimbalTransformName = obj_gimbal

gimbalRange = 3

}

MODULE

{

name = ModuleTestSubject

// nowhere: 0, srf: 1, ocean: 2, atmo: 4, space: 8

environments = 15

useStaging = True

useEvent = True

}

}

Edited August 12, 2014 by KerikBalm

[CavemanNinja]

I'm not really sure what to think of this, seeing as using this basically will make all ion gliders useless and therefore a waste of time...

great idea anyways, although isn't the atmospheric pressure on Eve enough to cancel the compressing effects of the high airspeed?

Edited August 12, 2014 by CavemanNinja

[EdFred]

Nothing says you have to keep the part after the challenge.

[KerikBalm]

Well, Ion gliders are pretty useless IRL, its kind of silly that we use them in KSP, I'd much rather see an electric fan.

An engine that reduces the prevelance of ion gliders is a good thing IMO.

As for the challenge, you can still use ions, perhaps for circularization - and you can use other engines, perhaps to get your craft up to speed so that the air augmented engine can produce more thrust. I'd say your submission doesn't need to use the engine at all, but as already noted, its quite impossible with the stock parts, so... I can't imagine such a submission would be competitive

What I'm worried about, as far as gameplay considerations, is making the aerospike obsolete. Sure, the vacuum ISP is worse, and the TWR and dry weight is worse, but I'm not sure that is enough.

"although isn't the atmospheric pressure on Eve enough to cancel the compressing effects of the high airspeed?"

Ummm I'm not sure where you are going with this.

Do you mean:

1) the compressing effects of a ram scoop are not needed, and it should be "air augmented" and producing full thrust from a standstill?

or

2) do you think it will not work with a very dense atmosphere?

1) If there is air there, it can be heated to expand and produce more thrust.

5 atmospheres is not all that much, the pressure in a jet/rocket engine/airscoop easily exceeds that by large amounts, and except for the very first moments when the rocket is fired, there shouldn't be enough air entering to provide any noticable air augmentation

2) as long as it can be further heated to cause expansion, it can be used to augment thrust.

In theory, this should be like a "super aerospike", producing equal vacuum ISP and better atmospheric ISP to conventional rocket engines, with the downside of a much higher weight - making it good in theory for escaping the atmosphere, but poorly suited for interplanetary journeys due to the high dry weight.

If the mixture is run fuel rich in an oxygen containing atmosphere, it is essentially a jet engine, very similar to the Sarbe.

However, you can still run such an engine - with added oxidizer, in an atmosphere that has no oxgen. Its not as good, since you need to bring your own oxidizer - but its stil better.

If we can have LV-Ns, why can't we have these rockets?

They've been in intermittent use in missiles since the late 60's (although typically running fuel rich and also exploiting atmospheric oxygen, and also typically using solid fuel)

Edited August 12, 2014 by KerikBalm

[CavemanNinja]

What i'm saying is because the atmosphere is so dense, it would take quite a bit bit more force to get the kind of expansion you'd find easy on Kerbin, or it might simply make the effects negligible, in which case you'd have a glorified RAPIER.

Also, your argument about ion gliders being silly I feel is pretty much void considering the game we're playing

Edited August 12, 2014 by CavemanNinja

[KerikBalm]

What i'm saying is because the atmosphere is so dense, it would take quite a bit bit more force to get the kind of expansion you'd find easy on Kerbin,

I cannot follow your reasoning as to why that would be.

Heated gas expands, even if it starts at 1 atm, or 5 atm, and the gas in a jet engine after going through a compressor is much higher than 5 atm anyway.

[MarvinKitFox]

I cannot follow your reasoning as to why that would be.

Heated gas expands, even if it starts at 1 atm, or 5 atm, and the gas in a jet engine after going through a compressor is much higher than 5 atm anyway.

Yep.

Only real effect would be that you could achieve the same thrust, with same energy input, from a *smaller* engine, due to the higher gas density being worked.

At least, until gas density gets so high that it starts to deviate strongly from ideal gas laws, and that requires millions of atmospheres of pressure.

[Jasonden]

Well, Ion gliders are pretty useless IRL, its kind of silly that we use them in KSP, I'd much rather see an electric fan.

This is in fact the solution that has been proposed IRL for flight on thick-atmosphere worlds: see the AVIATR idea for an airplane on Titan.