Using radiators in flight

[Laie]

Can radiator panels be used to shed heat from a supersonic cruise? I usually don't use them but have a vague memory of a panel suddenly going into action the moment I left the atmosphere, which would imply that it was prevented from working before.

[Spricigo]

Yes, radiator panels work in atmosphere. Of course you don't want to expose the deployable variant to aerodynamic forces but that is a different issue.

[bewing]

They work differently at different altitudes. If you are in the low atmosphere, they work well. In the high atmosphere, they only work a little bit.

[FleshJeb]

I remember reading something that said not to bother.

I know there's a couple of heat pump mods, but I've never tried them. I'd love to see one that "circulates fuel" to try to change or average the temperature of fuel tanks. Hmmm, one could use an interface, similar to the fuel flow priority, to designate which tanks are to be kept warmest or coldest. That way you could try to minimize the temperature of the tank behind the cockpit.

These were interesting:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750009264.pdf

http://www.dtic.mil/dtic/tr/fulltext/u2/912902.pdf (pg 63)

Edited November 2, 2017 by FleshJeb

[Laie]

5 hours ago, FleshJeb said:

I remember reading something that said not to bother.

Might have been me.

Right now I have the very special use case of a gentle entry with airliner wings. Those radiate well, so if you don't put too much load on them at any given time you can reach an equilibrium well below their critical temperature. The cockpit, however, will eventually get into trouble with it's core temp. In this particular case, a small amount of cooling may be fully enough.

Though truth be told, by now I just cranked up the cockpit's emissive factor and called it a day.

[FleshJeb]

8 hours ago, Laie said:

Might have been me.... [etc ]

I did some testing today with a single-engine Whiplash jet: The radiator wasn't helping much with sustained flight, but if I popped up high or slowed down for a bit, it made a difference. Of note, the one large radiator accounted for about 1/3 of the drag of the entire craft. Also, I think the Precooler may have a much higher overall emissivity than the Mk1 LF tanks. It was frequently exceeding or matching them and the radiator in a number of design options.