grafspee
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Posts posted by grafspee
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6 hours ago, Predator-78 said:
so in combat you set the RPM to 30?
Inviato dal mio SM-G998B utilizzando Tapatalk
If you want use full boost +18lbs you have to use 3000rpm, at 2850rpm you are limited to about +12lbs at 2650rpm you are limited to +7lbs. So in combat patrol i would use 2850 rpm and boost up to 12 and going in to combat i would increase rpm to 3000rpm and work throttle then, you don't have to fire wall throttle 100% of time in combat but make sure that you use max rpm so engine can take full boost.
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@virgo47 On top of that, all this values like power, crit alt , fuel flow are for v-1650-3 engine and engine simulated in DCS P-51 is V-1650-7.
V-1650-7 61/3000rpm S.L outputs 1590hp and war emergency is 1700hp but at lower alt. High blower alt with ram air for military power is around 26k ft. -3 can hold 61 inch well above 30k which is totally impossible for -7
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It could be many things, overcooling, not proper warming up , over stressing power settings for engine could be a bug too as well hard to say without track.
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Provide track with failure. This is the best way to find out what is happening.
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On 1/30/2024 at 6:30 PM, Rutch said:
Thank you. So in theory, the coolant temp should never drop below 60? Given the thermostatic valve in place?
thanks
Pretty much all thermostatic valves in coolant circuits consist small opening which is opened even when valve is completely closed, reason for this is to push a little bit of hot coolant to other side of valve so it can react quicker and with better precision, so in theory if you would cut throttle completely and put plane into long dive temp could drop below 60C but it would took a lot of time. Flying at even very low power like boost +0 at 2000rpm this setup should hold that 80C with no problem.
Another positive factor of this thermostatic valve is that warming engine up especially in sub zero temp will happen very fast due to that coolant flow through radiator is near zero up to 80C.
P-51 had special attachment, for cold weather to prevent overcooling in flight, which restrict flow through belly air scoop.
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18 hours ago, Rutch said:
Sorry to try and reopen this, but as people have observed, the overcooling appears to have been fixed. That said, the coolant temperature is still dropping below 40 degrees when flying at say 20,000 or 30,000 feet… or at high speed in a shallow dive from height
Should the radiator have an auto feature to prevent it dropping below 60 degrees?
All the best.
In spitfire coolant circuit should consist thermostatic valve which should prevent coolant temp going down too much. Iirc temp set was 80C.
In p51 temp is regulated via actuating shutter doors in spitfire those shutter doors have 2 fixed positions with no intermediate positions.
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On 11/22/2023 at 10:42 AM, KoN said:
You will find on multiplayer that Axis are 80% of time out numbered.
This is very accurate, in 44 Germans were outnumbered 10 fold.
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Even if there is no MW50 in tank you can still use 1.8 ATA but you can do this only at very high alt. And don't bother using manual cooling set it for auto and that's it.
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@Gunfreak There were many during WW2 which had problems with aim. So you are not alone.
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@Roosterfeet 38inch at 2400 rpm by all means should not kill engine, by heaving rpm and MP in green zone automatic mixture control will lean mixture for cruise.
The more important thing is how you reduce or increase power.
If you want to reduce power always retard throttle first for desired MP and then reduce rpm to proper level. In case when you increase power first set rpm then MP.
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@MAD-MM I am aware of bug report about oil temp in P-51 that oil temp can go off grid and engine feels fine. But i don't know if fix came in.
I know that in DCS features come in and are taken away constantly. Maybe cooling is still worked on or just team switched to something else and with newer patches things fades away.
Those are my temps in climb. To force system to work with lower temps is as fallows.
If you intend to climb with 180mph enter this climb and steep it so you lose speed to 150mph keep it there for a while and then drop nose and get to 180mph
this trick forces system to open shutters but once you drop nose and accelerate temps will drop but not enough to trigger shutter closing temps and there you go with that simple trick you can control coolant/oil temp in some extent w/o playing with coolant switches. Ofc you can manually open shutter and flip them back to auto this should work as well but i haven't test it.
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19 minutes ago, MAD-MM said:
Dumb question what happen when go over the red line for the coolant temperature in DCS?
Last time i checked it will blow relieve valve and vent coolant until almost all coolant is gone.
Everyone know that if water boils it stops gaining temp and adding heat only intensifies boiling process, same here in P-51 temp at which relieve valve opens will remain steady while coolant is boiling and only when major of it goes out temp will climb further up.
Unless relieve valve won't be able to even excess pressure in time and pressure in system will go up then coolant temp will go up as well.
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I've hit 97c at high alt max power dogfight.
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Our P-51 is late war model, where oil and other stuff was improved. Setting higher temps improves performance of the plane, you need much wider opening to keep 100C then to keep 113C coolant temp. In later P-51 manuals you can find that 95C oil temp was allowed while using WEP.
But engine optimal temps won't change.
You still get green temps while cruising at medicore power range. But for climb or combat power temps will get higher.
Green arc on gauges represents optimal temp range but operating temp range is much larger iirc for coolant it is 60C to 121C and for oil 15C to 90C ofc with respect to oil pressure limits.
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5 hours ago, Nealius said:
I'll fly it again but I was either at 42 or 46 in a slight climb, around 180~200mph. Coolant was beyond the green zone but not quite at the red line, like maybe 130 or 140? Oil temp was I think pegged right at the max of 90, maybe a couple degrees hotter. I had to open the coolers manually to get temps back into the green.
Redline for coolant is 121C and for oil 90C. I fly P-51 quite often and in auto mode temps are always below redline, and this is only what matters, automatic shutters aren't set up to maintain temps in green zone as P-51 maintenance manual states. Oil cooler doors won't open until 87C of oil temp is reached. Same with coolant, shutter door won't move until temp goes way above green zone. In case of the coolant temp gauge it may be 2 times thickness of the needle. In climb you will always be above green zone and this is totally fine.
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9 hours ago, Nealius said:
In AUTO I'm still getting very hot coolant and oil temps at 200mph, 42" 2700rpm (max cont. IIRC?) with OAT 8C, which seems a bit odd to me.
Can you specify what "very hot coolant and oil temps" mean, 46" 2700rpm is max continuous.
Automatic cooling shutters system has hysteresis, opening and closing temps for shutters are spread.
I can't remember exactly but opening coolant shutter temp is something like 110C and closing is something like 100C same with oil cooler shutter 87C opening and 80 closing temp, can't remember exact numbers it could be that coolant opening is at 113C.
When your coolant/oil temp is 112C/86C automatic system will not open coolers shutter doors, but if you increase power and those temps ticks up by 1C automatic system will start opening shutters and it will stop opening them when temps will drop below opening temps, at this point you have slight opened cooler shutters and if you reduce power and coolant and oil temp will drop by 5C automatic system will not adjust cooler shutters, it will react only when coolant/oil temp drop below closing temps.
That way when you are flying at 46" and 2700rpm temps can be as low as closing temps and as high as opening temps at same speed same OAT same power setting.
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1 hour ago, Skewgear said:
The tail-down moment that occurs when the main wheels touch down is overdone. Curious to see if anyone can reproduce a smooth touchdown like these sequences of KA114.
What astonish me is that back firing sound, as soon pilot cut throttle this amazing sound comes out of the engines, i wish ED could update that sound, i think they did not upgrade this sound when last time they upgraded ww2 planes sounds. Most of the sound pack is still like +10 years old.
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@stuart666 My point is that, let say A-8 critical alt for 1.42 ATA is 22k ft, if we get 1.56/1.65 ATA Anton it will have exactly the same ATA at that alt. So if you would fight in Anton up high (above 24k ft as example), it does not matter if it is 1.42 ATA version or 1.56/1.65 ATA version. This is only thing what i try to say.
Same apply to allied planes, 72" P-51 can hold that boost to lower alt then 67" P-51 and above blowers crit alt both will perform exactly the same, at 28k ft 130 P-51 and 150 P-51 will fly exactly the same no gains there from having 150 octane fuel.
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1 hour ago, stuart666 said:
Thanks, Ill definately try that out then.
Yep, Ill entirely agree with you.
And im not even suggesting they take anything out or modify anything. All they have to do is clone the A8 and give it the new throttle range, and maybe a 100 octane version of the P51. Considering all the effort they are going through to make a new theatre with marianas, and a hellcat to fly in it, this should be easy money for them. In fact, if they threw in some new skins, Id happily buy a late production A8 and an early P51D (perhaps without the filler on the tail and in green to make it truly different).
Lets put it this way, Id be more inclined to buy those than the Hellcat that, tbh, I struggle to develop interest in.
Thing is that increased ratings for A8 won't improve performance across all alt. It only allow engines to be operated at increased ATA at alt where supercharger can actually provide that boost, same with 150 octane fuel for allied planes.
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2 hours ago, stuart666 said:
I think the point im making is to model an earlier Mustang, so that the earlier A8 has something that it is slightly more competitive with, and a later one that, whilst still vastly outclassed, still has a bit more in the tank. If Greg is right (and I would encourage people to listen to his thoughts all the way through) it is not that the A8 wont be outclassed. Its just that modelling a late 1944 Mustang to go up against an early 1944 A8 really isnt particularly fair. Ok, so fair is still going to be outclassed. Well, you cant do anything about the history, but they are modelling two different eras of history. Its not even pretending to be historically correct.
I totally agree that we should get A8 with increased power rating.
Thing is that P-51D was one of first along with K-4 and D-9 which all of them are from similar period. Problem was created by introducing Normandy map which represents period 1-2 year before K-4 D-9 and P-51 D-30 which if i am not mistaken is 1945 Mustang model. Another issue is that ED decided to model early A8 production model with 1.42 ATA and not going for late version with 1.56/1.65 ATA along with 1943 Spitfire mkX which actually started its life as MKV and it was converted to mk IX in mid production, indication for this is shape of tail vertical stabilizer and rudder.
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1 hour ago, Rene Coulon said:
I am doing this ...Again. How a massive BUG like this passes into BETA is Nuts. and I know we in Beta...but stil.
It is hard to test every gpu and every gpu driver, so yes in beta things like this may slip through. If this bug related to specific gpu than it is very easy to miss this bug.
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I haven't experienced it too. I use DLAA too.
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@stuart666 P-51 D is fast as hell, but idea alone that P-51 B/C is 20mph faster at alt above 13k is crazy and 13k of alt isn't crazy altitude where you won't fight in MP. And on top of that P-51 B/C were upgraded along with D model introduction. So overall B/C is no less competitive then D model.
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23 minutes ago, stuart666 said:
I get the impression that in June/July 1944, the Americans still largely had B Mustangs, and the Luftwaffe had modified the A8 till have a greater power range on the throttle. The mustang likely still had ascendancy, but it didnt have what it did later with the D model (not least 4 guns compared to 6), and wasnt running 150 octane. I gather the power output of the D they have now is as it would have been in october 1944 till the end of the war, not what it would have had in june.
This is all on Gregs planes and automobiles. Im not buying the idea that the early P47 and P51B are offering an unassailable advantage, or clearly they would nt have introduced the later variants. More to the point, we get a B or C mustang, then you can operate them as RAF ones. The RAF only got D models in 1945 IIRC.
B/C used 1650 -3 and -7 engines , -3 is rigged for high alt so it provide lower power output and lower top speed at SL but at alt between 13k to 17k makes B/C up to 20mph faster then D same at alt above 28k where B/C faster then D.
British model of P-51B/C Mustang III when operated on 150 fuel was cleared for 25lbs boost which is 80inch in US planes made mustang III faster then any other US army P-51.
Why reduce RPM?
in DCS: P-51D Mustang
Posted · Edited by grafspee
Running engine at 3000rpm won't damage it, it will increase engine weare and shorten engine life time but it will not damage it.
And P-51 manual states that engine goes for full tear down inspection after 5 hours of accumulated WEP usage so NO, engines weren't replaced after single use of WEP. You could probably could go for more then hour of continuous wep before engine would give up. That would shorten engine life time to couple hours but life time of p51 engine was aimed for couple hundreds hours so equivalent time limitations were used