no bug High Oil Pressure, slowly increasing oil temperature

[Ramires]

After the last update the engines warm up pretty slow, oil pressure is at max and the oil temperature remains at the ambient OAT.

[grafspee]

I was flying Mosquito couple times to day and it warms up pretty well, and oil temp is steady just above 60C in flight at moderate power range, gets hotter in climb at high power.

Edited August 28, 2022 by grafspee

[Art-J]

The initial oil pressures are indeed higher, however, and so is the oil warmup time. It applies to Mustang as well. Just tested both for the first time after the update, on Marianas with 26 degrees OAT at ramp, so on a pretty warm day. Upon startup the oil press jumped to 150 in both planes and it took much longer to get it below 120, compared to previous game version.

I'm not saying it's wrong now, but one just has to get used to longer warmups and smarter oil dilution management...

... which brings the question - did this patch finally implement oil dilition in the Thunderbolt, or is it still inop? Haven't tested yet.

[grafspee]

19 minutes ago, Art-J said:

The initial oil pressures are indeed higher, however, and so is the oil warmup time. It applies to Mustang as well. Just tested both for the first time after the update, on Marianas with 26 degrees OAT at ramp, so on a pretty warm day. Upon startup the oil press jumped to 150 in both planes and it took much longer to get it below 120, compared to previous game version.

I'm not saying it's wrong now, but one just has to get used to longer warmups and smarter oil dilution management...

... which brings the question - did this patch finally implement oil dilition in the Thunderbolt, or is it still inop? Haven't tested yet.

I will divert a little bit but flying P-51 at 26 C OAT was PAIN before this update.

Just check it, oil dilution sill don't work in P-47

Mosquito and Spitfire has oil pressure gauges scaled from 0 to 120 psi, US counterparts have rang from 0 to 200 so it look a lot less drastic in US planes but oil pressure behavior improved a lot after this patch.

 

Edited August 28, 2022 by grafspee

[NineLine]

Please supply a track if still seeing an issue.

[NineLine]

Are you till seeing an issue, otherwise I will close this, thanks.

[Ramires]

Sorry for the late reply. I think you can close the topic. Rechecked the the engine warm up... It takes a much longer time now. But seems to work well. Well I'm not an engineer but it surprises me that the pressure was at the maximum of the gauge at ~20°C ambient air temperature at the very beginning of the startup (throttle in idle position). Has the Merlin 25 a max. oil pressure limitation? 

Can we expect a change in the Spitfire's Merlin as well.

 

Thank you for the great aircraft

[grafspee]

It is common for all engines, at cold oil pressure will be high to protect engine bearings, it can be couple times higher then normal operating pressure.

At least for P-51 according to manual ambient temp, below 7C is considered as extreme cold conditions and required additional things to be done before start up. 

Edited September 15, 2022 by grafspee

[NineLine]

6 hours ago, Ramires said:

Sorry for the late reply. I think you can close the topic. Rechecked the the engine warm up... It takes a much longer time now. But seems to work well. Well I'm not an engineer but it surprises me that the pressure was at the maximum of the gauge at ~20°C ambient air temperature at the very beginning of the startup (throttle in idle position). Has the Merlin 25 a max. oil pressure limitation? 

Can we expect a change in the Spitfire's Merlin as well.

 

Thank you for the great aircraft

Thanks for the reply, will need to be checked once the Spitfire is done as well, but should work similar. 

[hazzer]

Not to rehash an old thread but is there any documentation stating that a high oil pressure is to be expired on startup as depicted in the sim? 

It seems bizzar to me that the pressure builds so quickly and then goes off the gauge. 

My experience (albeit in much lower powered aircraft) is that the oil pressure slowly builds on start up. Certainly if it went off the gauge that would be cause for concern and would shutdown immediately.

I seem to recall the P51 oil pressure goes above the max line.. 

This is all starting up and not bringing the rpm above 1000.

[Skewgear]

19 hours ago, hazzer said:

Not to rehash an old thread but is there any documentation stating that a high oil pressure is to be expired on startup as depicted in the sim? 

It seems bizzar to me that the pressure builds so quickly and then goes off the gauge. 

My experience (albeit in much lower powered aircraft) is that the oil pressure slowly builds on start up. Certainly if it went off the gauge that would be cause for concern and would shutdown immediately.

I seem to recall the P51 oil pressure goes above the max line.. 

This is all starting up and not bringing the rpm above 1000.

I'm not sure the engine should exceed 90psi in normal operation unless it's very cold. The main oil pressure relief valve in the Merlin V-1650-3 and -7, as well as the Merlin 68 and 69 (all Packard built 60 series Merlins, almost identical to the M66 in the Spitfire IX) operates at 90psi to divert oil from the main lube oil circuit to the low pressure circuit via a low pressure (I.e. reducing) valve.

The diagrams and system descriptions I have access to in the RCAF V-1650 service manual aren't very clear about how these interlinked circuits operate, or where high pressure oil goes if the low pressure circuit is fully pressurised already. Like you, my real world experience is oil pressure starts at 0 and rises when a cold aero engine is started.

The Spitfire in DCS is roughly correct at the moment even though the numbers are all wrong (when you start the engine its oil pressure rises, peaks and then slowly falls as temperature rises). The Mosquito modelling after the recent cooling revamp is completely wrong (oil pressure goes off the scale and stays there, eventually settling at 120psi indicated).

Let's hope if the Spitfire cooling is updated that it isn't just copy and pasting wrong numbers and behaviour in again.

[hazzer]

On 12/15/2022 at 2:00 PM, Skewgear said:

I'm not sure the engine should exceed 90psi in normal operation unless it's very cold. The main oil pressure relief valve in the Merlin V-1650-3 and -7, as well as the Merlin 68 and 69 (all Packard built 60 series Merlins, almost identical to the M66 in the Spitfire IX) operates at 90psi to divert oil from the main lube oil circuit to the low pressure circuit via a low pressure (I.e. reducing) valve.

The diagrams and system descriptions I have access to in the RCAF V-1650 service manual aren't very clear about how these interlinked circuits operate, or where high pressure oil goes if the low pressure circuit is fully pressurised already. Like you, my real world experience is oil pressure starts at 0 and rises when a cold aero engine is started.

The Spitfire in DCS is roughly correct at the moment even though the numbers are all wrong (when you start the engine its oil pressure rises, peaks and then slowly falls as temperature rises). The Mosquito modelling after the recent cooling revamp is completely wrong (oil pressure goes off the scale and stays there, eventually settling at 120psi indicated).

Let's hope if the Spitfire cooling is updated that it isn't just copy and pasting wrong numbers and behaviour in again.

Many thanks for this. Glad to see that it's not just me.

Yesterday I flew the p51 in game and noticed the oil pressure actually went off the gauge/way higher than it should. More so than in the past (temperature in game was about 20°c) so very incorrect. 

 

Hope these things are looked into. 

[hazzer]

Was looking through YouTube to try and find a suitable cold start video. The only one I can find so far is of kermit weeks starting the p51C. Not the same but still relevant. You can just about see the oil pressure gauge on start up and it doesn't leap up and go off the scale as in DCS but instead remains within limits and quite low. 

@NineLine please can you revisit this and mark as a bug - this counts for most or all of the piston aircraft in the sim. 

 

Many thanks,

https://youtu.be/iompxanAQgQ

Edited December 29, 2022 by hazzer

[hazzer]

Anyone managed to look at this at all? I tried to post it on discord as well however the ED bot deleted my message twice. 

[hazzer]

Hello, this is still an issue. Today I launched dcs for the first time in a while. Started the p51 in 10°c and the oil pressure went above the red and up to 200. Obviously in the real world this causes blown seals amongst other issues. But more importantly this is not how the oil pressure should react. In reality it should be a slower rise, and considering I never went above 1000rpm on startup it shouldn't go over the red line. 

 

Once again I am asking to please reassess this oversight. You have the video above showing another p51 starting up and can see a realistic oil pressure rise. Obviously Nick and the rest of the TFC pilots would tell you if the oil pressure rises like it does in some of the dcs pistons they would be heading back into the hangar. 

[NineLine]

Can you send me a track, I am seeing it go up eye but come down right away, and never up to 200. Thanks.