How effective are precoolers?

[quasarrgames]

I cant tell how effective precoolers actually are when used in conjunction with turbojets or rapiers on spaceplanes. A small and completely faulty test i did seemed to reveal that rapiers get up to higher max speeds with more precoolers, but i'm not sure how much they actually improved efficiency.

Has anybody done any precooler tests themselves? What were the results?

[Warzouz]

They don't "cool" but

1- they have a little bit of fuel

2- they add intake air, even behind another intake

3- they have (but not sure) a big thermal mass for the mass of the part. They can "store" a lot of heat before blowing up.

I think usage is mainly RP.

[Mastikator]

I've been told they conduct heat really well. So put them onto things that overheat and then radiators or wings or something on the precoolers.

[Teilnehmer]

2- they add intake air, even behind another intake

Btw, how does the amount of intake air depends on the airflow direction relative to a precooler?

[RidingTheFlow]

They don't "cool" but

It does cool. It has same high emissive constant as radiators. Pre-1.0.3 I've used it to cool LV-Ns without need for any extra cooling (and probably still will considering that its matches LV-N in size and carries some fuel for it too - without need for extra radiator part).

Edited June 23, 2015 by RidingTheFlow

[tutike2000]

It does cool. It has same high emissive constant as radiators. Pre-1.0.3 I've used it to cool LV-Ns without need for any extra cooling (and probably still will considering that its matches LV-N in size and carries some fuel for it too - without need for extra radiator part).

It doesn't cool in the way most people would expect it to cool. A jet precooler in real life is supposed to increase thrust and fuel efficiency of the engine. In KSP it doesn't do that.