Engine Pre-Cooler still useless?

[g00bd0g]

Just wondering if anything has changed?

[swjr-swis]

21 minutes ago, g00bd0g said:

Just wondering if anything has changed?

I use the pre-cooler all the time. It's surface attachable, it's still the least draggy of the 1.25m intake+tank parts (and the -shared- lightest dry mass), and it is a bit better at pulling heat from attached parts due to its thermal properties - especially helpful with hot-running engines like the Whiplash or Nerv.

Care to explain with a bit more words what you mean with useless, or what change you are looking for?

[g00bd0g]

1 hour ago, swjr-swis said:

I use the pre-cooler all the time. It's surface attachable, it's still the least draggy of the 1.25m intake+tank parts (and the -shared- lightest dry mass), and it is a bit better at pulling heat from attached parts due to its thermal properties - especially helpful with hot-running engines like the Whiplash or Nerv.

Care to explain with a bit more words what you mean with useless, or what change you are looking for?

I've never had a problem with engines overheating, and it's not the best intake, so I'm just not sure why one would use it?

[FireKerb]

I'm going to assume that you've never built a spaceplane, because on them it is fairly good.

There are two problems when building spaceplanes. Heat and (mostly) drag. Most intakes are draggy. The pre-cooler, like other inline tanks, is less draggy than their nosecap counterparts. It can also dissipate atmospheric heating, and holds a decent amount of fuel. And intake air is barely an issue concidering you have to go pretty fast in a spaceplane. Actually, the only problems I ever get with intake air is when I forget intakes. I've never had a plane that used 100% if their intake air.

[bewing]

9 hours ago, g00bd0g said:

I've never had a problem with engines overheating, and it's not the best intake, so I'm just not sure why one would use it?

If you have something that absolutely has to go on the very front of your plane -- such as a klaw or a docking port -- then your only choice for air intakes are the inline ones. And the Precooler is by far the best inline air intake for multiple reasons given above. But I consider a shock cone to always be preferable if the nose is available for an intake.

 

[overkill13]

What do you cap your precooler stacks with when building space planes?  All of the intakes are less draggy than a precooler with a nosecone and weigh less.  I suppose if I need the 40 liquid fuel, but I can probably source that fuel somewhere else in the craft.

Edited July 1, 2018 by overkill13

[FleshJeb]

16 hours ago, overkill13 said:

What do you cap your precooler stacks with when building space planes?  All of the intakes are less draggy than a precooler with a nosecone and weigh less.  I suppose if I need the 40 liquid fuel, but I can probably source that fuel somewhere else in the craft.

NCS Adapter (under Fuel Tanks) and a 0.625 Small Nosecone for me. However, the blue-tipped Aerodynamic Nose Cone is the least draggy of all the nose cone parts.

[swjr-swis]

On 7/1/2018 at 12:05 AM, g00bd0g said:

I'm just not sure why one would use it?

19 hours ago, overkill13 said:

What do you cap your precooler stacks with when building space planes? All of the intakes are less draggy than a precooler with a nosecone and weigh less.

Choice is good. Don't restrict yourselves or your designs by thinking of conventional uses only, and consider also use cases in which the combination of properties of the pre-cooler makes it the best choice (or compromise). I'm not alone in responding here that I use it, so obviously people do find uses for it - open your mind to the possibilities.

Besides, I find the aesthetics and (imaginary) practicality of the part appealing too. I don't know how viable such an intake could be in real life (I don't think I've ever seen one), but I have a feeling that if engineers had such an option, it would be used a lot - no open ducts/funnels to mess up aerodynamic flow or to 'design around', no need to worry about bird strikes or runway debris, etc etc.

[ARS]

It's very useful for building spaceplane, good for aesthetic, saves part count and adjusting craft's balance

[Lego_Prodigy]

I use precoolers because the other inline intake does NOT play nicely with radial attachments. They are also very good at cooling off the engine a little. 

For a real world example of the precooler, it can be seen on a good number of supersonic cold war jets, from the famous SR-71 BlackBird to the slightly less famous  Bristol 188 "Flaming Pencil" (nicknamed for the fact that it was intended to be fast enough to have frictional heating).

[blakemw]

The main reason to use a precooler is if you want an intake with reasonable performance and you can't use a shockcone on the nose of the  ship because it will burn off (or other reasons, like wanting a shielded docking port). Shockcones have good thermal tolerance but bad other thermal properties, one factor which determines how easily something burns is "cross section exposed to heating" vs "skin area available to radiate heat", the Shock Cone being a short and stubby part can't radiate much heat. A reasonably pointy fairing makes the best nose cone for thermal tolerance and you can put stuff inside it like batteries, reaction wheels, probe core, antennas etc.

A single shockcone can supply 6 RAPIERs with air with the right ascent profile, so is very much overkill for a spaceplane with only 1 or 2 engines - which a precooler will suffice for. Using a Precooler + Fairing Nose with light/cheap 0.625m parts inside it can be a nice optimization for smaller planes.

[blakemw]

On 7/1/2018 at 2:19 AM, FireKerb said:

I'm going to assume that you've never built a spaceplane, because on them it is fairly good.

There are two problems when building spaceplanes. Heat and (mostly) drag. Most intakes are draggy.

1

Nose intakes are typically less draggy than nose cones, the Shockcone particularly has unnaturally low drag but all nose intakes are less draggy than comparable nose-cones. Intakes are typically heavier and (much) more expensive than nose cones and sometimes have less thermal tolerance.

Surface attached intakes can be quite draggy because in general the drag model hates surface attachment, but there are only two of them and neither of them are that good. Certainly given the choice between a surface attached intake or inline/nose-intake you should not go with surface attached.

Edited July 4, 2018 by blakemw

[Lego_Prodigy]

Ive grown fond of using unstaged fairings as aerodynamic nosecones, with added upsides including having adjustability.