Engine nacelles and pre-coolers - how do they work?

[michal.don]

Hi guys,

recently I was trying to build a MK3 SSTO plane capable of lifting ~40 tonnes of payload to LKO. After failing miserably for quite a long time, I decided to download a plane from pro-rocket-engineers, just to see what it takes to build a succesfull SSTO plane. Apart from design differences, the main thing I noticed is using of the above mentioned nacelles and engine pre-coolers, which I didn't use yet, just because I have no idea how they work or even what they are supposed to do But since they have been on the downloaded plane, I suppose they are important in a way that I don't know, and that led me to the question - engine nacelles and pre-coolers - how do they work?

Thanks,

michal.don

[Jaeleth]

They both have a function a cooling the air entering the engine, cooler air, denser air, denser air, more kick out of your engine at higher altitudes. Never used nacelles, use pre-coolers quite often.

[capi3101]

They're pretty much the same thing - they both provide a little bit of fuel (not really enough for a run to space), a little bit of intake air (again, not enough for a run to space), and a radial mounting point for an engine assembly (the last of which is probably its probably their best use, IMHO). That's pretty much it. The pre-cooler is ostensibly harder to heat up; myself, I've seen little difference between the two parts in practical usage. I do fly FAR, in which the pre-cooler is ever so slightly better in terms of less added drag (in general).

[LostOblivion]

They both have a function a cooling the air entering the engine, cooler air, denser air, denser air, more kick out of your engine at higher altitudes. Never used nacelles, use pre-coolers quite often.

Is this actually implemented?

[Xannari Ferrows]

Nacelles in real life are primarily for taking air in through the front to feed the combustion reaction for the aircraft.

Precoolers are to take in air radially, to which it travels through both an area of high and low pressure, being cooled along the way to allow a denser flow.

In KSP, they are just a combination of intakes and fuel tanks, and are almost no different from each other [aside from modelling that is]

[Van Disaster]

In KSP, they are just a combination of intakes and fuel tanks, and are almost no different from each other [aside from modelling that is]

Yeah, they're basically stack intakes; under FAR the precooler seems to be at risk of overheating frequently if the tank is empty, somewhat ironically. If you take the fuel out the pre-cooler is lighter than the Mk1 Fuselage Intake, though ( at a somewhat higher cost ). Not enough that it matters unless you're trying to save a few kg. A structural fuselage + structural intake is lighter still but no fuel tank.

[A_name]

and a radial mounting point for an engine assembly (the last of which is probably its probably their best use, IMHO).

Although you can always just attach a regular LF Fuselage radially as well, or am I missing something?

[Xannari Ferrows]

Although you can always just attach a regular LF Fuselage radially as well, or am I missing something?

Some of it is for aesthetics, but it's for when you don't want something too heavy, need a bit of extra fuel, and don't want to bother for other intakes.

Edited October 21, 2015 by Xannari Ferrows

[Sanic]

Precoolers boost engine performance. I've only tested it al low altitude with a turbo ramjet, but the precooler added some extra thrust.

[Foxster]

Precoolers boost engine performance. I've only tested it al low altitude with a turbo ramjet, but the precooler added some extra thrust.

Umm, nope.

[Nothalogh]

Engine nacelles and pre-coolers - how do they work?

They don't, they serve no functional purpose within the game currently.

Airbreathers only require a single high speed intake per engine for optimal performance

[Birdco_Space]

I may be mistaken, by in my experience, using similar aircraft, I get usable engine performance at higher altitudes with pre-coolers. I don't know if this the extra intake, or increasing the density of the air, but I am talking in the ball part of an extra 2000 ft of altitude before flame out on the turbo-ramjet. if flying a shallow profile, this helps a lot getting to orbit.

[Van Disaster]

It's the intake. The pre-cooler is literally the same thing as a fuel tank with an intake attached to it.

[michal.don]

Ok, it seems I am not the only one who doesn't know exactly Anyways, thank you all for your explanations,

michal.don