Running coolers full open

Does anyone know if there are any adverse effects resulting from running the oil/coolant radiators wide open full time? I'm thinking drag, but thats about all I can come up with.

I've noticed in automatic mode, the oil temp particularly will push redline at 46"/2700rpm and 200kias climb. You would think that when the oil temp is pushing redline the doors would open a bit more in auto mode, but strangely I am able to achieve additional cooling by going manual and opening them up myself.

Oil viscosity is closely tied to temperature, so if the temperature is not inside the operation range, it can lead to problems like decreased engine service life.

Also, piston engines are very sensitive to certain parts tolerances (piston seals, e.g.), if those don't have the right temperature (due to coolant being too cold, for example) it can result in degraded engine life as well.

Oil viscosity is closely tied to temperature, so if the temperature is not inside the operation range, it can lead to problems like decreased engine service life.

 

Also, piston engines are very sensitive to certain parts tolerances (piston seals, e.g.), if those don't have the right temperature (due to coolant being too cold, for example) it can result in degraded engine life as well.

Thanks sobek, do you happen to know if that is modelled in the sim?

Dumb observation, but I would think that if the cooling modes are set to auto, and overheating occurs, shouldnt they open based on temp rise? No, I didnt read the manual, so maybe there is a reason why you have to do this manually, I dont know, just makes sense to me that it should run auto. As you all know, in the heat of a dog fight. looking down to check temps can kill ya!

So if I understand you correctly, when we are starting to over temp, and we are already set to Auto, there is no need to manually flip the switch to AUTO, although that seems to cool things down?

There was a bug where the regulator would only start to work once you put the switch to manual and back to auto. If the regulator is undamaged and the switches are in auto, there should be no reason for you to worry about temperatures unless you are flying very slow at high power.

hmmmmm.... very interesting! I am aware that there are still guys out there opening manually even while in Auto with the perception that it is effective, so I am confused but will have to evaluate this with a few other guys. Thanks for the feedback

hmmmmm.... very interesting! I am aware that there are still guys out there opening manually even while in Auto with the perception that it is effective, so I am confused but will have to evaluate this with a few other guys. Thanks for the feedback

There was some confusion with the markings on the temp gauges and the actual working temperatures, in case of the oil temp gauge, those do not match. People concluded that the regulator was faulty and resolved to regulating manually, when in fact, it was working.

There was some confusion with the markings on the temp gauges and the actual working temperatures, in case of the oil temp gauge, those do not match.

Was this an error on the real P-51, or is it a problem with the sim?

Id like to respectfully request a formal response to this if possible, even some more feedback from you guys out the flying Multiplayer. With the guys I have been flying with, there is uncertanty about whether or not these coolers are truly running in auto? I myself, before I taxi cycle the cooling switches from Auto to On, then back to Auto, and hope its all set, while another has this function mapped to his HOTAS and uses it. Now I must admit, while in the heat of a dog fight, your watching the bandit as best you can while monitoring Manifold pressure, RPM, Air Speed, altitide etc,, its dificult under those circunstances to stop what your doing, look at the temp guages, cycle the cooling to on and hold it and watch the temp guages, your pretty much either going to hit the dirt or get eaten alive by bandits. So I would like to know if there is any need or benefit to cycle cooling on manually please. Thanks,

There was some confusion with the markings on the temp gauges and the actual working temperatures, in case of the oil temp gauge, those do not match. People concluded that the regulator was faulty and resolved to regulating manually, when in fact, it was working.

For the oil temp. gauge and the regular, they are at different part of the system, and at different temp if the the RPM of engine or radiator flap door is changing.

Id like to respectfully request a formal response to this if possible, even some more feedback from you guys out the flying Multiplayer. With the guys I have been flying with, there is uncertanty about whether or not these coolers are truly running in auto? I myself, before I taxi cycle the cooling switches from Auto to On, then back to Auto, and hope its all set, while another has this function mapped to his HOTAS and uses it. Now I must admit, while in the heat of a dog fight, your watching the bandit as best you can while monitoring Manifold pressure, RPM, Air Speed, altitide etc,, its dificult under those circunstances to stop what your doing, look at the temp guages, cycle the cooling to on and hold it and watch the temp guages, your pretty much either going to hit the dirt or get eaten alive by bandits. So I would like to know if there is any need or benefit to cycle cooling on manually please. Thanks,

I agree. I guess my original post was asking if there were negative effects modelled in the sim that result from running the engine too cold - but the larger point that you hit on is the level of effectiveness of the coolers in auto mode. Based on my testing at time compression 20x in single player just flying around i was not able to overheat an engine with coolers full open at 61/3000. In auto, the engine failed. So while it would be nice to have an official response, test it yourself and see if you get the same results.

A friend and I were flying some multiplayer in P51s over the Christmas break, we found without fail that we would suffer engine failure shortly after take off or fail to generate full power on take off if we did not manually open the coolant and oil cooling fully. After take off I flew for several hours with coolers fully open while my friend used auto once we took off and got a few thousand feet and got to a cruising speed of around 250. My temps remained cool for the entire time (not sure if it would have affected service life in real life but no problems in mission) and my friends would vary between slightly hot and slightly cool - I assume this is the normal slightly lagged response of the automatic mechanisms responding to heat going over a certain level and opening the coolers and then closing them as the temperature dropped to maintain a correct average.

If you leave things in auto on startup you'll fry with the coolant hitting 150 degrees by the time you've taxied out to the runway. We even tried fully opening things manually for startup and then putting them in auto and moving to the runway as quickly as possible and found that we'd take off and suffer engine failure due to overheating about the time the wheels were in the wells. When we opened manually and reset to auto after climb out and getting to crusing speed we had no further trouble.

I too would like an official response of whether the bug is still there (which is seems to be) and what the correct workaround until it's fixed is so things are more predictable in game.

Cheers,

Stonehouse

I always leave the radiators at auto during startup and have never fried the engine that fast. Maybe it's because I do not use much throttle during take off and lower prop pitch after getting airborne. Still, the weird thing is the only engine failure I suffer is during a continuous climb and there is never any indication in the engine sound that something is about to go wrong and when it does the prop just stops instantly and doesn't budge after that. Not sure if that is the way it's supposed to be (it should at least turn a bit when in a dive?).

Stonehouse - what is the ambient temperature at your starting airfield? It sounds like the auto function works in air but clearly something is awry on the ground. I've been starting with OATs of 15-20 and haven't managed to fry the engine yet. Shortly after takeoff I am throttling back for the climb and this keeps the temps fine. Your experience at 250 mph and a few thousand feet altitude is also different to mine: with the rads in auto my coolant and oil temps are low and I have to manually close them to get the dials in the green. Of course, forgetting to open them for a touch and go DID seize the engine and I'm sure the local farmers were pleased with my furrow!

FWIW, I can't get my carb temps away from zero using the above parameters.

I will try again later with a bit more RPM and Hg and see what happens.

If you watch real P-51 start ups, the radiators are left manually open on the ground. Once you get airborne, lower the prop pitch and you'll be absolutely fine. The auto rads do not always keep you within the green so you will see temps slightly hot or slightly cool before it reaches a value which triggers a response to either increase or decrease the temperatures.

Running the coolant doors fully open did not cause me any problems when I tried it in the past (over 1 hour of formation aerobatics with coolant doors fully open and no issues at all). But, as I understand it, I think running with slightly cool temperatures would cause longer term affects, not an instant failure?

With that being said, I always fly the Mustang well within it's limits and so I have never over heated the engine to a point which has caused it to fail on me.

Was this an error on the real P-51, or is it a problem with the sim?

The sim works according to RL documentation. Why the marks are where they are on the gauge that was used as reference is still the cause for some confusion, AFAIK.

If you watch real P-51 start ups, the radiators are left manually open on the ground. Once you get airborne, lower the prop pitch and you'll be absolutely fine. The auto rads do not always keep you within the green so you will see temps slightly hot or slightly cool before it reaches a value which triggers a response to either increase or decrease the temperatures.

As i already said, in case of the oil temp gauge, the green arc does not correspond with neither the ideal working temperature nor the cooling door actuator control logic. The actual working temperature is relatively close to redline. The green arc on the oil temp gauge has no relevance and should be ignored.

Im starting to see some real good feedback with the perception of uncertanty! Good, because that is where my thoughts still are.

Now Im going to add this to my thoughts :

"The green arc on the oil temp gauge has no relevance and should be ignored."

I honestly must say, I am not feeling any closer to resolving my question, I actually feel furthur, in a sence, from resolve? Is it just me? If so, I will let it go and chalk it up as my lack of comprehension. Thanks,

The auto position works as IRL.

Thanks, but since I dont fly one in real life, do I have to fiddle with it for any reason? I have to presume based on your statement that Auto means "Auto" and it will modulate as it needs to so there is no need for me to manually open the actuators for any reason as it is AUTOMATIC, correct?

And the Oil Temp guage is to be ignored, correct? (another topic if so)

So keep my fingers off it and leave it in "Auto" Correct?

(im wearing myself out with this one LOL)

Again, AUTO works as IRL, that is, once a certain threshold is reached, the logic opens the door further and the same vice versa for closing the door. There should be no need for you to manipulate the doors, however, you have to allow for some delay in heat dissipation due to the slow speed of the actuators, so for example, it is not a good idea to go from a high speed/low power dive into a low speed climb by slamming the throttle forward because this will suddenly introduce a lot of heat into the system and the actuators might not be able to open the doors fast enough.

What this all boils down to is that you need to work the airplane within its limitations. No control logic is psychic, even more so since the control is a simple hysteresis type and not proportional or even more fancy, so when you have large power transitions, depending on the situation, you may need to allow for the actuators to react.

Edit: Another example for how to screw over the auto controller would be taking off in cold weather with the doors in AUTO. The engine produces little heat at idle, so the controllers will keep the door closed, but when you take off, you have a large and steep power transient, aggravated by the fact that you are at slow speed, this can quickly lead to a fried engine.

I believe that explanation helped me alot, I not only understand that I really shouldnt have to mees with Auto, but I can now understand the typical reaction time of the actuators will not in all case overcome or meet the sudden needs. Thank you for taking the time to explain furthur.

Sorry forgot about this one "the Oil Temp guage is to be ignored". Is this currently an accurate statement?