Oil and radiator control = optimal engine performance?
 

Hi all, have been playing this sim for a while but have just recently come to realise after reading other threads that oil and radiator settings seem to affect plane performance i.e. climbouts, speed at various alts?

Pardon my ignorance but can someone explain to me how this happens? :confused:

In the 109 for instance, I normally fly it with oil and radiator fully opened no matter what happens.

Is this advisable?

radiators act as surfaces that stick out the more you open them, which in turn disturb the airflow around them, affecting the aerodynamics of the AC thus reducing it's speed.

that's the case in RL, and portrayed with reasonable accuracy in CLoD. there's no reason to go fully open all the time, just monitor water and oil temps frequently and adjust accordingly.

as a rule of thumb you can go with oil rad at 50-60% but you'll have to work with the water rad much more frequently; worry if the oil rises above 85ºC, water must not exceed 102ºC for long, but you'll soon find that once above 98ºC you'll be struggling not to let it rise; above 105ºC it's an engine wrecker, if you can maintain it bellow 97-96ºC then you're in optimal regime. high RPMs tend to heat up the oil, but reducing RPMs and opening the oil rad up to 4/5 takes care of the issue; the water heats as the engine goes hotter, all you can do if it starts to overheat is go full open and throttle back for a while.

for more info you should take a reading at the many threads discussing this, it's not very difficult to figure

as always, practice makes perfect; happy flying ;)

Got it now :grin:

Thanks Jatta!

my experience is that there isnt any difference in performance whether the rads are fully open or almost closed in the 109s.
i really doubt that its modeled correctly right now.
i reach the same top speed with rads fully opened on deck like i do with rads almost closed.
but of course too high temperatures will kill your engine.

I fly with them fully open. I tried to notice any speed difference when I close them in flight and did not.

Just tried them at various settings, dun think I noticed any difference too.

Oil 5 clicks open, water 40% open (thats two bars on the wing indicator if you can see it.)

Of course, not good. I read, if the pilot need to air-braking, often opened the radiator instead of flap because they handled it more quickly. This behavior occurred between the half and full opening stage strongly...

I just tested it in level flight with the 109E-1... I get 402km/h with water/oil rad fully opened, and I get roughly 434km/h with em closed. :-P

Yeah rads are inducing drag. The default's CoD FM is correct.

Of course if you are flying with some amount of side slip or at a low pitch you won't notice any difference ;)

For the correct settings, don't forget that at low alt it would be more difficult to cool oil/glycol fluids in most situation -> the radiator opening would hence have to be wider (a strong point for cruising at alt ;) )

@ Kein : you can reach easily 480/490 level with the E.

490? How?

I suspect a strong feel of disbelief in your words Tom :grin:

But anyhow I convinced myself to (re)write the answer :

Increase your speed by diving slightly at 5m/s. Once your reach 500+ (usually somewhere btw 520/540) level your nose and keep your trajectory straight with the utmost of attention. Your oil&glycol rads shld be nearly fully closed (at high speed the amount of airflow would be enough to cool your eng).

And Taaada ... Th's it :D Your speed will stabilize at 500 and then will very slightly decrease to 480/490.

Note that with a very shallow descent (what was authorized by international authorities for high speed record) you can keep 500 IAS deck (with something like 50m/min descent (150ft/min)

I'll give it a try, Tomcat, but I'm not sure if I believe that is sustainable in truly straight n level flying. ;)

Btw, my results came from me cruising at exactly 100m above the English Channel: damn near sea-level.

No it's not. If it was it wld not hve been called max speed but max cruising speed ;) Heat will soon force you to open the radiotor.

Now I see what you're talking about. Yes, that's totally possible. I think Tom got mixed up because I brought up level flight first. :-P

:grin:

Ok, i understand now. Yes, the current FM keep the energy, but i thought you can reach the 500 with pure engine power :cool:

TomcatViP I have a quick question on "low pitch". Are you referring to prop pitch (fine)? I am noticing no difference on the Spit/Hurri with the raidator, but I am still learning the finer points of trimming for speed.

Hmmm... I also have a second question. Not sure about German aircraft but the Spit and Hurri don't have aileron trim. I am having the issue that I often have to use ailerons to fly straight and level with my slip & turn indicator is showing the plane is properly centered. But I do notice a definite increase in speed.

Am I doing something wrong?

Hi Mop,

to clear the situation (;) ) I was there talking about the angle of the blade with the plane of prop rotation (= pitch).

In the 109, the needle indicating the prop pitch, turns counter clockwise. This is the trigonometric positive way in maths that means that an angle is increased by opening a wedge from the right to the left and decreased on the opposite way (clockwise). This is why (only my own opinion) the indicator in german plane is done that way. WHen the needle turn that way, it indicate that the angle of the blades is increased.

Obviously, it's natural to refer to hourly induication, like 11h30, 10h etc... but keep in mind that in fact it refer to an increase of the pitch.

So I was effectively talking abt a high drag situation where your prop turn at high speed without pushing air bckward = blocking the air from flowing => Drag.

Regarding the ammount of left/right stick needed to counter the rudder action, it's pretty normal. In most of the plane you will fly, rudder action induce a rolling moment that need oposite aileron to balance the plane.

It comes easily with the time. Just find a comfortable position where your hand's own wheights will suffice to create the small roll action needed.


I hope it helps.

The joy or levelling off from a dive at high speed with the radiators closed, the prop coarse and the engine purring at low rpm. You can hold onto that extra top speed for longer than if you had the engine screaming and the rads open.

I don't know exactly how much extra speed I really get, but it certainly sounds good

I read in IvanK's post (regards the FM research and testing he has been contributing) - that currently there is no drag penalty for rads and the devs are aware of this.


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I am not going to get in a tit for tat ref the charts or the tests depicted on them. In all cases they represent the climb performance achieved in game using the Climb profile (Power/speed) as quoted in the source documents themselves.

In all cases RADs full open (since at present there is no radiator drag in COD). These climbs are all straight out standard climbs NOT max power (i.e. without WEP/Boostcutout).

In the course of these climbs it was also discovered that both the Spitfire and Hurricane VSI's were overreading to the tune of 800fpm for the Hurricane and 1000fpm for the Spitfires. This determined by Alt versus elapsed time.... so dont rely on the VSI's at present to give you a true indication of climb rate. Altitude versus time is the only true measure.

The Spit Ia is with CSP controlling at 3000RPM.
The E4 is in AUTO controlling at 2350RPM (No advantage doing it in manual btw)