Spitfire Rads - How closed do you go?

[PeterPanPan]

I fly mainly Spits with CEM on. I also always fly with rads fully open to avoid overheating. But I suspect this is being over cautious and slowing me down too with the drag from a fully open rad. So, the question is, how closed can you go in average flight conditions to get the best balance between speed and avoiding cooking your engine? I suspect there is no simple answer, but let's see ...

Thanks

PPP

[Trooper117]

Set to normal once in cruise.. close rad if it starts to drop out of normal operating temp..
Just monitor temps really.

[ATAG_Snapper]

Set to normal once in cruise.. close rad if it starts to drop out of normal operating temp..
Just monitor temps really.

+1

[ATAG_Dutch]

Fully open for take-off, then once airspeed, pitch and boost are set, and the a/c trimmed for the climb at 160 IAS, I reduce to halfway (or about 8 or nine clicks if you use buttons), check trim again and pretty much leave it there.

I close it fully when diving with power off, then open up to normal. As the other chaps have said, keep glancing at the temps. Prolonged fine pitch/high revs sends your oil temp soaring, but a few seconds of coarse pitch brings it down again really quickly.

I very rarely boost the engine beyond +5 unless in combat, and open rad fully when I do.

[skouras]

same with Dutch

[PeterPanPan]

Thanks chaps, very useful indeed. What is 'normal' setting though? Was there such a setting in the real world or are we talking about simply half open? Will check tonight, but is there any cockpit indication (other than the position of the 'handbrake') of where the rad is?

Thanks

PPP

[ATAG_Dutch]

Thanks chaps, very useful indeed. What is 'normal' setting though? Was there such a setting in the real world or are we talking about simply half open? Will check tonight, but is there any cockpit indication (other than the position of the 'handbrake') of where the rad is?

Heh, heh. Normal for me is halfway. I read somewhere that pilots used to line the 'handbrake' up with the corner of something on the cockpit wall, but I forget where I saw this and also what it was. But yes, 'halfway' is 'normal' for me, there's no cockpit indicator as such.

This is one of the reasons I prefer to fly the Hurri, as it has an indicator - which is a bit strange because I'm a typical Spitfire nut.;)

[ATAG_knuckles]

Half way for me as well



Denis

[41Sqn_Stormcrow]

One has to note that the Merlin can really get easily very very hot. I realized that during take off and at some altitudes even with low rpm and fine pitch (lever back) it easliy heats up for the Spit1 to nearly 100 despite rads fully open ...

[JG52Uther]

Interesting info, thanks! I have been playing around with the Spit 1 online lately, and leaving the rad fully open (and flying around with fine pitch all the time) so will try it half closed.

[SEE]

Same as Dutch except for Mk1 Spits, I T/O with half Rad and leave it alone at around or just over 3/4 throttle and climb at around 1800 ft per min - same for level flight. Combat/full throttle - open Rad accordingly.

[justme262]

I've noticed that if I line up the top of the handle with the bulkhead that extends down from the dash board I can run at full power with out over heating.
I close it more in a dive with power off but There is no reason to open it more than this really.
Maybe if I was at high altitude and low airspeed climbing full power and fine pitch...

I have never tested it so see how much drag it really causes but I have heard the real pilots used to mark a line on the wall .