Oil temp threshhold for engine breakage? (Mainly Merlin engines)

[*Buzzsaw*]

Originally Posted by Crumpp

That is wrong.

The higher you go, the less effective the cooling due to pressure and density reduction despite the cooler temperatures.

So while the temperature does get cooler IAW the lapse rate, the density is reduced so we end up with less molecules to transfer heat away from our engine.

I can't say I am an expert on this matter. I made the assumption there is enough flow with the higher speeds at altitude and the cooler temps to cool the aircraft faster. Ie. IAS at sea level and 6000 meters may read the same, but TAS is much higher at altitude, and therefore airflow is much higher.

Anyone else want to comment?

[Crumpp]

IAS at sea level and 6000 meters may read the same, but TAS is much higher at altitude, and therefore airflow is much higher.

Airflow is not much higher because of True Airspeed.

[bongodriver]

Indicated airspeed is what matters, if indicated is high enough then cooling will be sufficient.

[ACE-OF-ACES]

Originally Posted by bongodriver

Indicated airspeed is what matters, if indicated is high enough then cooling will be sufficient.

Bingo!

[ATAG_Dutch]

Originally Posted by Crumpp

That is wrong.

Originally Posted by ACE-OF-ACES

Bingo!

Nothing changes here, does it?

Oil temp. Whatever settings people tell you to fly at, fly at less, apart from airspeed. Whether it be RPM or boost. Most people in a game fly at max poss everything all the time. Total rubbish.

What is the oil temp at which your engine blows? Find out. Run your mouse over the oil temp gauge and wait for it. Try it at different rpms. Try it at different boost settings. Just fly. Offline until you find out. Then you'll know.

Everything is there for you to find this out for yourself. Go to it.

Edit: 97 degrees. If memory serves correctly........

[Crumpp]

Indicated airspeed is what matters, if indicated is high enough then cooling will be sufficient.

Why don't you take the time to explain the relationship of Indicated airspeed, True airspeed, and altitude?

Then take some to explain the general behavior of a altitude effects on thrust production at constant power setting and indicated airspeed.

After you have done that, you can sum it all up as:

Crumpp says:

The higher you go, the less effective the cooling due to pressure and density reduction despite the cooler temperatures.

[bongodriver]

Originally Posted by Crumpp

Why don't you take the time to explain the relationship of Indicated airspeed, True airspeed, and altitude?

Then take some to explain the general behavior of a altitude effects on thrust production at constant power setting and indicated airspeed.

After you have done that, you can sum it all up as:

OK then:

if you climb at constant airspeed then true airspeed increases with altitude, at constant indicated airspeed the 'mass' of air flowing through the cooling system remains constant with the added effect of reduced ambient temperatures.
penalties of high altitude on performance are not really a factor, bottom line is if you keep the same amount of air mollecules passing through the cooling system then you won't have problems cooling, I'm not entirely sure where crumpp gets the theory that maintaining constant indicated airspeeds is not possible but everyone else understands that a constant reading on the airspeed indicator means constant indicated airspeed and we also know how to achieve it.
To some extent engine temperatures will also fall off with the natural reduction of power with altitude also.


Oh and

Looking forward to the next installment from the Nonsensical Administration of Crumpp Aeronautics

p.s. I'll post you a picture of what high altitude shows on the Learjet PFD tonight as I have an empty sector back from Denmark tonight.

[JtD]

Originally Posted by ATAG_Dutch

Nothing changes here, does it?

Annoying, isn't it? I don't think this is the best subject to make generalisations, because temperature over altitude characteristics depend on aircraft, engine, engine settings, flying regime. So I suggest to find a different excuse for being rude to each other.

[NZtyphoon]

Originally Posted by JtD

Annoying, isn't it? I don't think this is the best subject to make generalisations, because temperature over altitude characteristics depend on aircraft, engine, engine settings, flying regime. So I suggest to find a different excuse for being rude to each other.

I suggest that no-one argue with Crumpp because it is patently obvious that he is THE undisputed expert on everything.