Shock Cone Intake vs Ram Air Intake

[_stilgar_]

Hello, this is my first post here

My question is - which one is better - shock cone or ram intake? I see people are saying that shock is better, but in the game it has lower values - 0.009 intake area vs 0.01 for ram and 0.9 air amount vs 1.0 for ram.

So, if Shock is better, could anyone explain to me, why is that?

[Sharpy]

Seconding. I think I recall Shock Cone having less drag and better thermal characteristic, while taking less air, but I'd prefer someone more experienced to have a say.

[mrclucks]

I think ram intakes are best due to the description saying it works best at faster speeds, but it may be all fluff

[viktor19]

I think ram intakes are best due to the description saying it works best at faster speeds, but it may be all fluff

This great forum community taught me not to trust the part descriptions, especially those written by Squad. Regarding the intake dilemma, I also read somewhere that shock cone has better heat resistance and is less draggy. The second one probably makes up for less Intake air capacity (difference is only 0.1, folks!)

[Mic_n]

look at the weight on em.

shock cone intake is outrageously heavy, and the ram has a larger area. Unless you're specifically trying to recreate a MiG-21 or something, I'd say go with the ram air every time.

[_stilgar_]

(difference is only 0.1, folks!)

0.1 of 1.0 is 10%. 9 rams = 10 shocks.

look at the weight on em.

shock cone intake is outrageously heavy, and the ram has a larger area. Unless you're specifically trying to recreate a MiG-21 or something, I'd say go with the ram air every time.

That was my conclusion as well...

[Cebi]

This calls for test. I wont be able to test it soon, but i would take whiplash engine, precooler, probecore and stick ram/shockcone intake on the top. Then only thing left to do is launch it verticaly and note highest altitude reached.

[Mic_n]

This calls for test. I wont be able to test it soon, but i would take whiplash engine, precooler, probecore and stick ram/shockcone intake on the top. Then only thing left to do is launch it verticaly and note highest altitude reached.

Just take a look at the numbers in the part.cfg files. I haven't looked much lately, but in the old days it was really just a matter of intakearea. Some have a higher capacity of intakeair, but given how low those capacities are relative to how quickly it's burned, that really doesn't matter much.

[Sharpy]

This calls for test. I wont be able to test it soon, but i would take whiplash engine, precooler, probecore and stick ram/shockcone intake on the top. Then only thing left to do is launch it verticaly and note highest altitude reached.

Also note top speed please.

edit: I tried my own tests. The rocket with RAM seemed to fly somewhat slower... resulting in exploding due to overheating later I'm not sure how to read these results, whether the overheating was late due to better thermal capacity or due to lower speed.

Edited July 10, 2015 by Sharpy

[Warzouz]

Test protocol could be hard because this is very dependant on the flight pattern.

Maybe with a mod which would allow to control 2 ships...

[Sharpy]

PART
{
    name = [B]ramAirIntake[/B]

    mass = 0.01
    thermalMassModifier = 12.0
    emissiveConstant = 0.7
    angularDrag = 1
    MODULE
    {
        name = ModuleResourceIntake
        area = 0.01
        intakeSpeed = 10
    }
    RESOURCE
    {
        name = IntakeAir
        amount = 1.0
        maxAmount = 1.0
    }
}

PART
{
    name = [B]shockConeIntake[/B]
    mass = 0.025
    thermalMassModifier = 8
    heatConvectiveConstant = 0.75 // air goes into jet, not bashes on intake.
    emissiveConstant = 0.95
    angularDrag = 1.2

    MODULE
    {
        name = ModuleResourceIntake
        area = 0.009
        intakeSpeed = 12
    }
    RESOURCE
    {
        name = IntakeAir
        amount = 0.9
        maxAmount = 0.9
    }
}

These are the relevant differences. I culled all identical and irrelevant entries.

Okay, someone care to explain their meaning?

[viktor19]

Test protocol could be hard because this is very dependant on the flight pattern.

Maybe with a mod which would allow to control 2 ships...

BurnTogether?

[NathanKell]

You missed the DRAG_CUBE differences.

Shock cone advantages:

1. Lower drag

2. For its area, lower convective heating

Ram advantages

1. Lighter

2. More area

[Nich]

Shock also takes in more maximum air at higher speeds .01*10 < .009*12. I think I normally run 2 or 3 engines on 1 intake anyways so I don't think it really matters

[ajburges]

Oh, this thread again.

Conclusions from empirical testing in 1.02 (can't be bothered to find a link to the thread):

> Shock cones have significantly less drag

> Shock cones are heavier

> Drag difference typically more significant for LKO based craft

> Little, if any, difference in heat management

> Closing the intakes: it does nothing!

Fun note the shock cone is also the lowest drag 1.25 m part period. (as of 1.02)

[Sharpy]

...so, I'd be better off mounting shock cones instead of nose cones on my rockets?

[Foxster]

...so, I'd be better off mounting shock cones instead of nose cones on my rockets?

Correct.

[selfish_meme]

Red Iron Crown tested it, shock cones win, plus little nosecones on the ends of Rapiers are worth it too. Drag is king.

[ajburges]

Red Iron Crown tested it, shock cones win, plus little nosecones on the ends of Rapiers are worth it too. Drag is king.

... for Kerbin, Eve, and Laythe. Duna's atmosphere is a little thin for drag to be king and Jool is a special mission anyway.

[Wanderfound]

Red Iron Crown tested it, shock cones win, plus little nosecones on the ends of Rapiers are worth it too.

Worth noting, however: only in stock. If you want more realistic drag physics, Ferram is waiting for you as always.

[Sharpy]

... for Kerbin, Eve, and Laythe. Duna's atmosphere is a little thin for drag to be king and Jool is a special mission anyway.

Unless you have some "alternate launchpads" mod, Kerbin alone is sufficient.

I'm seriously considering replacing my SRBs with jet boosters now. With gravity turn they won't sputter out long after SRBs would be discarded, and they are small enough not to be a burden to the orbit.

[ajburges]

Meh, jets are a poor replacement for SRBs.

SRBs are about TWR, jets are about ISP. They are quite heavy and expensive as your primary lift engine. Especially from a stand still.

[Sharpy]

BACC: thrust 300.0, TWR climbing from 3 to 17

S1: Thrust 670.0 TWR climbing from 2.2 to 13.45

Whiplash: top thrust 754, TWR 43. (though that will drop somewhat with fuel tank and intake).

Besides, Whiplash will keep accelerating at the time I'm through the second stage of BACCs and finishing an S1.

I believe a ring of hammers to get the initial 100m/s or so would still be acceptable, but the real work would be better done by jets.

edit: peak TWR of Whiplash + small tank (with oxidizer removed) + intake is 734000 newtons / ((earth gravity)*2112.5kg) = 35.43

TWR at rest is 6.27

Edited July 14, 2015 by Sharpy

[AaronLS]

Drag is king.

That's why I use inline nacels, and stick the adapter on front that adapts from that size down to the size that a "small nose cone" fits. That adapter holds 80 fuel.

That nicely tapered nose is pretty low drag and the inline gets occluded and seems to thus have much less drag.

Although everything I say is in question without proper expirment

[Red Iron Crown]

Red Iron Crown tested it, shock cones win, plus little nosecones on the ends of Rapiers are worth it too. Drag is king.

I did? I think you are confusing me with someone else. The tail connector part is the lowest drag nosecone as determined by empirical testing. I use ram air intakes on my planes because I like the way they look, the performance difference between them and the shock cones is not overly large.