wip Over-cooling

[Catseye]

Still there yesterday flying in Beware, Beware.   2650 rpm -2 boost rad auto to stay with the formation.  Engine siezed on egress and at interception point with bandits. Good timing:)  

[grafspee]

Spitfire and Bf-109 wasn't included in new cooling system beta update. So nothing have changed for spit and k-4

[Catseye]

5 hours ago, grafspee said:

Spitfire and Bf-109 wasn't included in new cooling system beta update. So nothing have changed for spit and k-4

Understood and it is a shame. Such super scenarios set up by Reflected that cannot be flown until this problem is resolved.  I really feel for the person that has put so many hours into developing a campaign only to be the victim of ED's inability to effectively support a genre for so long. Shame!

[Nealius]

For those situations in the campaign I've had to forego formation integrity and S-turn above/below the formation. Since human players don't have instand acceleration and unlimited energy like the AI, we need to keep some speed on for the merge anyway.

[Catseye]

15 hours ago, Nealius said:

For those situations in the campaign I've had to forego formation integrity and S-turn above/below the formation. Since human players don't have instand acceleration and unlimited energy like the AI, we need to keep some speed on for the merge anyway.

How did you manage your fuel consumption doing that and get back to Biggin Hill and without engine siezure?

 

[Nealius]

7 hours ago, Catseye said:

How did you manage your fuel consumption doing that and get back to Biggin Hill and without engine siezure?

Slipper tank, running my engine at around 2650/+4 or so. My rad temp was barely above 60. If it dipped low I would increase boost for a bit until it came back up. Never really had an issue with fuel management as long as I had a slipper tank on me.

[Catseye]

16 hours ago, Nealius said:

Slipper tank, running my engine at around 2650/+4 or so. My rad temp was barely above 60. If it dipped low I would increase boost for a bit until it came back up. Never really had an issue with fuel management as long as I had a slipper tank on me.

Similar for me except -2 boost.  Hmmmm.   Also, slipper tank empty crossing into France. Thanks for the feedback.

Edited September 13, 2022 by Catseye

[Nealius]

7 hours ago, Catseye said:

Also, slipper tank empty crossing into France.

That's about when mine typically ran dry too. 

I think the times I "made fuel" were usually on the return trip. I don't remember my parameters exactly but I used something greater than 0 boost and greater than 2400, maybe right at +2/2400, and just watched that rad temp like a hawk. Any time it dipped below 60 I would run the engine at a higher setting for a bit to increase the temp, then go back to cruising.

Edited September 14, 2022 by Nealius

[Yoda967]

On 9/14/2022 at 2:48 AM, Nealius said:

I don't remember my parameters exactly but I used something greater than 0 boost and greater than 2400, maybe right at +2/2400, and just watched that rad temp like a hawk. Any time it dipped below 60 I would run the engine at a higher setting for a bit to increase the temp, then go back to cruising.

 

@Nealiusgot me to thinking -- I wonder what descent profile most folks are flying when their engine dies from overcooling.

*I am not saying that the cooling in the DCS Spit is working as it should* BUT "shock" cooling is a thing widely acknowledged by manufacturers of modern high performance engines. Yes, I am aware that it's a controversial topic; Avweb has articles denying its existence, but Lycoming and Continental both state that cooling an engine too quickly can result in cracked cylinder heads, warped exhaust valves, bent push rods, and other nasty, engine-killing things. Fast letdowns at low power settings are the most common actions associated with sudden cooling. (And in DCS, we currently have to worry about low engine temps at normal cruise power settings, too.)

That said, and with the understanding that the current cooling in the DCS Spitfire is broken, I think Nealius is onto something worth keeping in mind even after ED corrects the cooling problems in the Spitfire: Engine power during the descent needs to be managed so that the engine doesn't cool too quickly. 

Lycoming has a general service directive out that recommends cooling the engine at less than 50 degrees F per minute. Rate of descent should not exceed 1,000 fpm. Continental makes similar recommendations for their engines, and for their high performance turbocharged piston engines, suggests staying at cruise RPM and reducing power by 1" MP per thousand feet of descent. In the Spit, that would be about 0.5 psi power reduction per thousand feet. 

I haven't tested this in the sim, yet, but I suspect it might save some headaches. 

Has anyone found any contemporary guidance on how to manage the engine in non-combat descents? There doesn't seem to be anything in the Pilot's Notes, and I haven't read anything in any of the books I've read that were written by wartime Spitfire pilots. 

Sorry if this has strayed too far afield from the OP.

[Skewgear]

I don't think there is any real world wartime guidance on not overcooling the engine, mainly because the Spitfire is well known for running hot and overheating on the ground. Probably something to do with the 80C cutout in the radiator circuit which is not correctly modelled in DCS, which I find strange given what the module manual says.

Perhaps modern operators,  who run at what us gamers would consider very low power settings, might have some kind of internal wisdom they share with their pilots. One major operator of two-seaters trains their pilots to select -5lbs boost and 1850rpm when turning downwind in the circuit, and I imagine that leaves temps on the lower side.

The BBMF flies their LF.IX, MK356, at cruise settings between 1800rpm and 2100rpm, no higher than +4lbs boost. Their limitations document for the Spitfire IX also says normal oil pressure is 60-80psi at 0lbs boost and 2000rpm. In DCS I've never seen oil pressure lower than 90psi with the engine running, no matter the power setting or temperatures.

[grafspee]

With thrermostatic system in spitfire you cant overcool engine if engine is running, even idle would provide enough heat to keep temps high.

Overcooling problem is mentioned in p51 manuals but this one has difrent cooling setup

Edited September 16, 2022 by grafspee

[Art-J]

@Yoda967 Mind you, what's being discussed here affects the DCS Spit even in econo cruise, way before descent is initiated. When you can't fly level with historic power settings, you know something smells fishy. Now we can only wait and see what the upcoming, revised cooling simulation brings.

[666]

I think its extremely disappointing that this has not been addressed by this late stage in the Spits release! Me personally, have bought modules that I had no serious intentions of ever really utilising other than for a bit of fun on rare occasions and more importantly, as a way helping ED fund further development of current and future modules. In fact, the very reason I first got into DCS was for the Spit (and F16) which was my very first purchase and after all of my voluntary unnecessary extra support, here I am still waiting to be able to enjoy the very thing I got into this extremely expensive hobby of mine for! I even gifted a friend (no regrets) quite a few modules to help him develop a love for this sim because the entry price would've been a show stopper for him without having had the chance to get the bug first. I have parted with over USD $1350 since 2019 as my order history attached will attest to and you ED are making it very hard to stay in the mindset of spending anymore on DCS going forward. Your failure to take this issue as seriously as it should be taken is a stain on my relationship with ED and DCS.

Edited October 19, 2022 by 666

[grafspee]

@666 I can only tell that that thing is coming up soon, ED released partial new cooling system recently and we are waiting for second stage, which will include long awaited missing spitfire's cooling feature i hope. I don't know how ED scheduled this but i assume that second stage will include K-4 and spitfire cooling update which was missing from first one and probably many tweaks too.

Edited October 19, 2022 by grafspee

[Pyrocumulous]

Still not fixed.

[grafspee]

3 hours ago, Pyrocumulous said:

Still not fixed.

Yes no cooling updates since

[Rutch]

On 7/26/2022 at 11:34 AM, Yo-Yo said:

In the current version of DCS Spit flies at 9400 m at IAS 280-300 kph using 2400-2500 rpm to have 0-1.5 lb. Water temperature is not less than 60 , oil - 55C. No overcooling due to thermostatic valve. As the Spit was just released this valve was not operative by mistake..

Thank you for your reply. The problem as I see it is; the engine coolant over cools (falls way below the minimum) when flying at angels 10 or 20 and using conservative power settings I.e. 2000RPM and +0ibs boost or when descending from altitude (the engine will die). The only solution is to dilute the oil, which isn’t ideal. 

[Pyrocumulous]

On 2/6/2022 at 4:44 AM, BIGNEWY said:

We are waiting for devs to finish cooling work on the Mossie and then that will help with the spits cooling work, I can give no ETA currently. 

Thanks for continuing to be patient. 

Just a reminder that the Spit is still over-cooling.

[Davee]

Dec. 16 after upgrade the rad temp guage still runs very cool. Does not rise above 60 deg. at 20K alt. and on long descent drops below 10 degrees. Ran prolongued rpm's at this alt and experiemented with boost settings from full to 4 lbs. Temp guage did not deviate. Engine does not stop as it used to when on prolongued cruise despite cool temp guage. 

What should the new numbers be?

[Wiggy]

Agreed. Spit is exactly the same as it was before:(

[algherghezghez]

If anything the update made it worse

[Yo-Yo]

What do you consider "overcooling"? The lowest temperature of the coolant is  about 50C that is the thermostatic valve setting. If 60C is ok for takeoff, this temperature is ok for climb power, for example, and after a while you can apply full power without any hesitation.
If you see some differences comparing to P-51 with the same engine, take a brief look to the remaining radiator installation exit  area for both planes, and no further explanation is necessary, I think.

 

P.S. The new model does not change heat balance basics, so nothing changed in this regard.

[grafspee]

24 minutes ago, Yo-Yo said:

What do you consider "overcooling"? The lowest temperature of the coolant is  about 50C that is the thermostatic valve setting. If 60C is ok for takeoff, this temperature is ok for climb power, for example, and after a while you can apply full power without any hesitation.
If you see some differences comparing to P-51 with the same engine, take a brief look to the remaining radiator installation exit  area for both planes, and no further explanation is necessary, I think.

 

P.S. The new model does not change heat balance basics, so nothing changed in this regard.

Dcs spitfire manual says that thermostat is set at 80C and below this temp all coolant is directed in to pump inlet bypassing radiators. 

So ED should make up mind on this matter. If thermostat is set at 50C manual should be corrected or set thermostat to 80C.

I don't believe that 50C is ok for engine, low oil temp favors oil dilution with fuel and water.

If every manual states that thermostat is set to 80C why not do that?

P-51 may have the similar engine but cooling system is done way different. Mustang regulates temp via shutter doors and spitfire via thermostat and shutter doors which has 2 positions only, full open and normal operation position.

 

Edited December 19, 2022 by grafspee

[Davee]

1 hour ago, Yo-Yo said:

What do you consider "overcooling"? The lowest temperature of the coolant is  about 50C that is the thermostatic valve setting. If 60C is ok for takeoff, this temperature is ok for climb power, for example, and after a while you can apply full power without any hesitation.
If you see some differences comparing to P-51 with the same engine, take a brief look to the remaining radiator installation exit  area for both planes, and no further explanation is necessary, I think.

 

P.S. The new model does not change heat balance basics, so nothing changed in this regard.

The temp guage for me stayed at 40 degrees or less. Did not rise on warmup with rads closed before takeoff. During flight, it was usually around 10 degrees with a variety of settings from cruise to full power including rpm changes all prolongued. Only once did the guage get to approximately 60 degrees. If the cooling process has been changed, should not the guage reflect that? Not sure what I am to expect in this regard.  

Thanks,

 

[Yo-Yo]

60 C is good to apply full power, it is not a matter of faith, because it is from the manual...

Please, show the original manual with 80C, and we fix it.

1 hour ago, Davee said:

The temp guage for me stayed at 40 degrees or less. Did not rise on warmup with rads closed before takeoff. During flight, it was usually around 10 degrees with a variety of settings from cruise to full power including rpm changes all prolongued. Only once did the guage get to approximately 60 degrees. If the cooling process has been changed, should not the guage reflect that? Not sure what I am to expect in this regard.  

Thanks,

 

Please attach the track/