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Sorry if the answer has been posted before. I find this aircraft the most highly immersive sim aircraft I've ever flown and enjoy learning more about it.

I know it's probably not realistic at all, as I understand the Spit is a high alt interceptor, BUT.. if you have a high outside temperature, say 90 degrees F or higher, is it possible to cruise at say 5000 feet for any length of time? Or do you have to get to altitude right away? Is there an OAT above which the Spit simply could not operate at?

I tried this today - OAT 94 deg F at Phoenix. I managed for a while be running at low RPM's with the radiator about 2/3 open, but then the temps got away from me.


Thanks.

I tried to takeoff from Castle (KMER) where it was 100f and tried to fly across the mountains to San Jose at 8000 feet. It was too hot and the radiator boiled over no matter what I did. Later, I tried the same flight at 20,000 feet and had no problems at all.

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Jim

Hi. I do sometimes this "GA Style Flying" at low altitude at summer temps. Whether you can keep her cool enough depends also on the condition of your engine. If the cylinders are already in the yellow range it becomes much more difficult to keep her cool.

If the engine is in proper condition, I can start on the ground, taxi and takeoff at a ground temp of ~86°F (30°C). I then can cruise at 3000 ft with about 25°C OAT without problems, but the RAD does not get lower than 110-112°C, Oil 85°C. I am not sure if this stresses the engine too much if done for long time. It is also no good starting point for any fancy aerobatics at this altitude.

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You need to read the Radiator Tutorial on this site.

With care and proper technique she can be operated at low level but she is NOT at home there. Stay FAST (230+) and keep the radiator shutter to normal or one past normal only. Any more and you will likely cause more drag than it is worth.

Also, what do you call "low RPM"? Operating the way you are, I would be flying at +2 boost and 2400rpm more likely than not.

Speed is the single biggest factor in reducing temps...use settings that keep you above 200mph in the most efficient way possible.

I can fly at 5000 for a good while without problems but it took a fair bit of practice and experimentation. One BIG factor in low level is the lack of room to move on current temp (downwards) so the cooler you get into the air, the longer you can fly low. If you are at 120C on takeoff, you will have all sorts of problems getting teh temp lower...but if you get off by 100-110C you will be able to stabilise those temps and have a better shot at it.


I have taken off in 40C heat and managed 3 circuits (which are BRUTAL on the Spitfire due to slow speed, high power and landing gear and flaps obstructing airfow through oil cooler and radiator) before I had to pack it in and I just boiled on taxi in.

Also remember, boiling is NOT the end of the world, it is just a "condition" that needs to be dealt with. If it is let go too long, it will start to do damage but in teh short term it is not a grave problem.

If left though, the coolant levels will drop, then you get "behind the curve". Most people who say "my radiator spiked suddenly up to 140C" have actually been flying on reduced coolant levels for one reason or another. Less coolant, higher temp, more coolant boils off, suddenly..spike and fire.


Darryl

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...

Erlk0enig,

The easy answer is no, temps below 120C radiator and 90C oil will not damage the engine at all.

She will cruise happily all day at 88C oil and 120C radiator but you need to ask why the temps are that high. It could be a hot day, it could be mismanagement of the engine, or it could be indicative of problems (as you said,
cylinders a bit worn etc)

(or a bloody undercarriage leg blocking the intakes )


Darryl

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...

Thanks Darryl for this info.

No, you are right, if she runs that hot, I know most of the time the root cause Have roughly 50 hours now on her without boiling, just the Shutdown/Heatup-thing which causes too much wear..... Making too many short hops. OK another topic I'm quiet

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...Some say he never blinks, and that he roams around the woods at night foraging for Merlin parts...

Killratio,

thanks for the reply. I have read the tutorial, but I guess I'm still digesting it .

I was operating at 2000 rpm +2 boost. But couldn't get the temps lower.

I'll try again at 2400rpm +2 like you suggested. Maybe also the 2/3 radiator setting I was using was causing more trouble than it was worth.

Thanks.

Yeah, that's the thing about mechanical water pumps, they run proportional to crank speed so more revs might not be as detrimental as it would seem.

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