Can't boil the water in the Spit IX :-)

[Guest deleted@50488]

No matter how high my power settings are, full throttle, climb ahead 90º until tailslide, and then hold it there, climbing at near stall … and my temps are still well within the limits for quite a while, until I give up...

 

Isn't this a bit too much optimistic ?

Edited June 1, 2018 by jcomm-in-combat

[Pict]

4 minutes ago, jcomm-in-combat said:

Isn't this a bit too much optimistic ?

 

Highly likely...

 

If you can't boil the water, you can't make tea....no tea = no RAF  

[Herne]

50 minutes ago, jcomm-in-combat said:

No matter how high my power settings are, full throttle, climb ahead 90º until tailslide, and then hold it there, climbing at near stall … and my temps are still well within the limits for quite a while, until I give up...

 

Isn't this a bit too much optimistic ?

 

I don't think its too optimistic until someone can show any historical evidence to the contrary. 
 

The only thing I have seen about cooling problems for the spit ix while airborne are related to the landing gear not fully retracting blocking airflow to the radiators.

 

Edit: look at take off for example. starting from 0 MPH full rpm and high boost and yet some people think the engine should quit just because you drop below 180 MPH.

If that was the case pilot reports would not be so favourable about the spitfire. We would all be hearing / reading pilot accounts where they say she was lovely to fly but you had to be so damn careful in combat with your engine.

Edited June 1, 2018 by =FEW=Herne

[unreasonable]

PN says limit to climb is one hour at +12 and 2850, the radiators are fully automatic, and the coolant (glycol +water IIRC) has a maximum allowed temperature of 125 deg for one hour - (and 135 for 5 minutes), I think you are way off the mark with this one. 

 

If you climb for an hour like this, go to combat power for over five minutes, on a summer map - and you still cannot get it to overheat (ie above 135) you may have a point.

 

[Art-J]

Jcomm, maybe BoX Spit has the magic radiator cores borrowed from BoX P-40 ?. That would make it practically immune to overheating.

 

How about we try do a torture test on a summer map, running up the engine on the ground to as high boost as wheel brakes allow to see if we can go above 125.

Edited June 1, 2018 by Art-J

[Barnacles]

Maybe they added that extra radiator for a reason other than aesthetics.

[DD_Arthur]

Are we in actual fact discussing the peculiarities of the DCS Spitfire flight model? 

[Barnacles]

3 minutes ago, DD_Arthur said:

Are we in actual fact discussing the peculiarities of the DCS Spitfire flight model? 

lol

[Art-J]

It's possible DCS went overboard with the radiators effectiveness in one direction, it's also possible that BoX went overboard in the other. That's what we might want to investigate.

 

The second radiator was there on MkVIII+ for a reason, but so were temp and speed limitations outlined in the PN.

[Guest deleted@50488]

29 minutes ago, DD_Arthur said:

Are we in actual fact discussing the peculiarities of the DCS Spitfire flight model? 

 

Ya nailed it ? / touché ?

That's actually my only other reference, and I was lazy enough not to search for RW data on the subject ?

 

I recall that model did overheat quite easily... but it's been such a long time since I last used it...

 

Anyway, I'll repeat my tests since the ones I performed were at the BERLOGA MP server, in which I didn't check what Season was under use.

 

@unreasonable: Thx for the PN quotes - I should have searched for that before posting....

Edited June 1, 2018 by jcomm-in-combat

[-TBC-AeroAce]

I'm just gonna put it down to spiffing British engineering. 

[=621=Samikatz]

The only plane I regularly have temperature issues with is the Yak-7B tbh, I think most radiators are a little overmodelled

[Barnacles]

30 minutes ago, jcomm-in-combat said:

 

Ya nailed it ? / touché ?

That's actually my only other reference, and I was lazy enough not to search for RW data on the subject ?

 

I recall that model did overheat quite easily... but it's been such a long time since I last used it...

 

Anyway, I'll repeat my tests since the ones I performed were at the BERLOGA MP server, in which I didn't check what Season was under use.

 

@unreasonable: Thx for the PN quotes - I should have searched for that before posting....

I think Berloga uses a really low temperature so people can do mad skillz

1 hour ago, Art-J said:

It's possible DCS went overboard with the radiators effectiveness in one direction, it's also possible that BoX went overboard in the other. That's what we might want to investigate.

 

Totally agree. Out of the Sims I've played, DCS seems at the 'prone to overheat' side of what's credible (with the spit and stang NOT the k4)whilst seeming to generally obey the laws of thermodynamics. BoX is also generally credible apart from on the ground, as it is very hard to recreate the situations you hear about with planes cooking whilst idling. (doesn't bother me, it's a flight sim not a taxi sim) I think the consensus is it's the 'running cool' side of what's credible, but that may be prejudiced by there being quite a lot of cool maps and experiences of 1946 and CloD, which used overheating as a mechanism to prevent use of full power all the time.

[unreasonable]

1 hour ago, jcomm-in-combat said:

 

 

@unreasonable: Thx for the PN quotes - I should have searched for that before posting....

 

My pleasure - I have hard copy only from Amazon but I noticed someone in another thread say they found them online somewhere for free download. No guarantee that their PC is not now being used as a global distribution server for cannibal dwarf snuff porn, now, but at least they saved a few quid.

 

I assume that you do not have them rather than just forgot to read them - in which case you are looking for A.P. 1565J, P&L-P.N.  Pilot's Notes for Spitfire IX,XI & XVI  (Amazon version is from Crecy Publishing).  A very good buy. There is also a pdf here - beware cannibal dwarfs. http://zenoswarbirdvideos.com/Images/spit/SPIT9MANUAL.pdf

[9./JG27golani79]

4 hours ago, =FEW=Herne said:

 

Edit: look at take off for example. starting from 0 MPH full rpm and high boost and yet some people think the engine should quit just because you drop below 180 MPH.
 

 

If you are referring to my post in the other topic then I´ve never said I thought the engine should quit because I dropped below 180mph.

I was just curious that it lastet that long and that I didn´t even get into any temperature troubles because when it quit it suddenly quit without even overheating.

 

And abusing an engine like that (climbing at full boost and full rpm with a very low speed ~100mph) and not even be able to overheat on a summer map looked just a bit crazy to me.

Edited June 1, 2018 by 9./JG27golani79

[RedKestrel]

52 minutes ago, unreasonable said:

 

My pleasure - I have hard copy only from Amazon but I noticed someone in another thread say they found them online somewhere for free download. No guarantee that their PC is not now being used as a global distribution server for cannibal dwarf snuff porn, now, but at least they saved a few quid.

 

I assume that you do not have them rather than just forgot to read them - in which case you are looking for A.P. 1565J, P&L-P.N.  Pilot's Notes for Spitfire IX,XI & XVI  (Amazon version is from Crecy Publishing).  A very good buy. There is also a pdf here - beware cannibal dwarfs. http://zenoswarbirdvideos.com/Images/spit/SPIT9MANUAL.pdf

Avialogs.com is a site that has a lot of pilots notes and aircraft manuals, and I use it a lot. You can view them for free online but to download them you have to have a subscription. I'm happy enough with online viewing for now. As far as I know I'm not part of a massive north korean botnet so I assume its a safe place to go.

[Herne]

35 minutes ago, 9./JG27golani79 said:

 

If you are referring to my post in the other topic then I´ve never said I thought the engine should quit because I dropped below 180mph.

I was just curious that it lastet that long and that I didn´t even get into any temperature troubles because when it quit it suddenly quit without even overheating.

 

And abusing an engine like that (climbing at full speed and full rpm with a very low speed ~100mph) and not even be able to overheat on a summer map looked just a bit crazy to me.

 

Nah mate. Truth is I have no first hand knowledge of War Bird cooling systems, and i'm interested to learn the answers as much as anyone else. I don't get why people give the spit such a hard time though. I've read references to early models overheating on the ground "on a hot British Summer day" but read hardly anything suggesting problems while in the air.
 

Zoom climbs in my opinion would be a requirement of any fighter though, no matter if you are chasing, or escaping. Perhaps too much abuse should cause problems, but only if there is evidence out there to back it up.

I mentioned 180 MPH only because of how other games have chose to model the overheating problem.

[von_Tom]

 

Bear in mind that pilots were highly trained and would have been keeping a constant eye on temperatures.  They would also have flown in such a way to minimise temperature problems unless in dire need.  Combat would mostly have been very short-lived so flying around at max boost/RPM would not have occurred for prolonged periods.  Even running home at 300mph would be fine as most of the time you'd only need to do that for 30min or so to get to a safe base.

 

I would not expect to read any reports of overheating save for in test flights or where there were mechanical problems with the cooling system or battle damage etc.  Most RAF pilots seem to praise the Merlin as being ultra reliable and that can only be because they used it properly.

 

BTW I have no idea if the modelling is correct.

 

von Tom

[unreasonable]

29 minutes ago, RedKestrel said:

Avialogs.com is a site that has a lot of pilots notes and aircraft manuals, and I use it a lot. You can view them for free online but to download them you have to have a subscription. I'm happy enough with online viewing for now. As far as I know I'm not part of a massive north korean botnet so I assume its a safe place to go.

 

I just downloaded this from there, without a subscription. Maybe different categories.  Malwarebytes thinks there is nothing nasty in this, btw, sorry dwarf lovers. 

 

 

SPIT9MANUAL.zip

[RedKestrel]

8 minutes ago, unreasonable said:

 

I just downloaded this from there, without a subscription. Maybe different categories.  Malwarebytes thinks there is nothing nasty in this, btw, sorry dwarf lovers. 

 

 

SPIT9MANUAL.zip

Hmm, it really must depend on the content chosen. I just tried to download a P-47 manual and it told me it was only available for premium members. So maybe some is available for free download and others are not.

[thrila]

For interest:

 

There is a cooling report for the spitfire IX to determine suitability for +25 boost. I don't have a copy (perhaps some here does), however the figures for coolant temperatures were below 100°C after 5 mins of +25 boost in level flight with radiators closed for summer standard atmosphere at full throttles heights.
 

 

[unreasonable]

Just one more point now that everyone has the manual, OT to water but onT for Spitfires: do not forget that the IAS you see in the game is not corrected for position error, so it will always be a bit out. PEC chart is in the manual. Over most of the range this only matters for precise navigation over longish distances, but at very low speeds the PEC gets quite large. How large is a matter for debate, but even at 120-150 mph PEC is +4.  So if the manual says you should be at 120 mph in the approach, in the game you have to be at least 124.

 

This gets even worse at close to landing speed - and stalling speed, hence stall IAS in game are about 10mph higher than the manual says. So this does not mean the FM is "wrong" just that the game does not model certain instrument errors, unfortunately.

[LukeFF]

4 hours ago, RedKestrel said:

Hmm, it really must depend on the content chosen. I just tried to download a P-47 manual and it told me it was only available for premium members. So maybe some is available for free download and others are not.

 

ww2aircraft.net has almost all the pilot manuals you'll ever want to download, free of charge. There's no reason to pay for them somewhere else.

[69th_chuter]

4 hours ago, unreasonable said:

Just one more point now that everyone has the manual, OT to water but onT for Spitfires: do not forget that the IAS you see in the game is not corrected for position error, so it will always be a bit out. PEC chart is in the manual. Over most of the range this only matters for precise navigation over longish distances, but at very low speeds the PEC gets quite large. How large is a matter for debate, but even at 120-150 mph PEC is +4.  So if the manual says you should be at 120 mph in the approach, in the game you have to be at least 124.

  

This gets even worse at close to landing speed - and stalling speed, hence stall IAS in game are about 10mph higher than the manual says. So this does not mean the FM is "wrong" just that the game does not model certain instrument errors, unfortunately.

 

 

Actually, PEC is only used for (precise) navigation as it gives you your actual speed which is important for time and distance calculations.  All other speeds listed in the manual, such as various stall and best cruise or climb, are IAS (as indicated in the notes) as it was those incorrect instrument numbers that were recorded.  As a matter of fact, I don't recall any flight manual I've ever seen or used using anything but IAS for non-navigational reference.

[Holtzauge]

That the in-game Spitfire Mk9 does not overheat even when prophanging at WEP stallspeeds is totally realistic and due to the ingenious radiator design attributed to the gifted French engineer Maximilian Rollingbeau who later defected to the USSR where he joined the renowned Lavochkin aileron balancing department.

[Venturi]

... and some people do not know what a NEGATIVE, versus a POSITIVE PEC means...

[LukeFF]

56 minutes ago, Holtzauge said:

That the in-game Spitfire Mk9 does not overheat even when prophanging at WEP stallspeeds is totally realistic and due to the ingenious radiator design attributed to the gifted French engineer Maximilian Rollingbeau who later defected to the USSR where he joined the renowned Lavochkin aileron balancing department.

 

Cheap shot, man. Not cool.

[BraveSirRobin]

1 hour ago, Holtzauge said:

That the in-game Spitfire Mk9 does not overheat even when prophanging at WEP stallspeeds is totally realistic and due to the ingenious radiator design attributed to the gifted French engineer Maximilian Rollingbeau who later defected to the USSR where he joined the renowned Lavochkin aileron balancing department.

 

 

Maybe because the cooling system was optimized for 25lb boost.  It’s amazing how quickly a Russian bias dev becomes a German bias dev and then a British biased dev.  It all depends on what cheap shot you’re taking.

[RedKestrel]

5 minutes ago, BraveSirRobin said:

 

Maybe because the cooling system was optimized for 25lb boost.  It’s amazing how quickly a Russian bias dev becomes a German bias dev and then a British biased dev.  It all depends on what cheap shot you’re taking.

LOL I've already seen accusations of german bias among the dev team. IT BEGINS!

[JV69badatflyski]

1 hour ago, Holtzauge said:

That the in-game Spitfire Mk9 does not overheat even when prophanging at WEP stallspeeds is totally realistic and due to the ingenious radiator design attributed to the gifted French engineer Maximilian Rollingbeau who later defected to the USSR where he joined the renowned Lavochkin aileron balancing department.
 

I admire the art, it's close to perfection.
Do you have belgian origins?

PS: will keep that quote!

Edited June 1, 2018 by JV69badatflyski
Textformat

[unreasonable]

8 hours ago, chuter said:

 

 

Actually, PEC is only used for (precise) navigation as it gives you your actual speed which is important for time and distance calculations.  All other speeds listed in the manual, such as various stall and best cruise or climb, are IAS (as indicated in the notes) as it was those incorrect instrument numbers that were recorded.  As a matter of fact, I don't recall any flight manual I've ever seen or used using anything but IAS for non-navigational reference.

 

The point is that game instrument  IAS =/= RL IAS, because while RL instruments are subject to position error the game ones are not. The PN PEC chart converts from observed IAS to corrected IAS: ie you read the RL instrument as 120-150mph, then add 4mph to get the corrected IAS.  In the game we already have the corrected IAS. Then, if you were doing navigation, you would have to convert to TAS depending on altitude, and speed over the ground taking into account wind speed.

 

As to Venturi's comment - we have been all through this before and I have no intention of doing it again, except to extract from the Spitfire IXs PN which is unambiguous. If your RL instrument was showing 120-150 mph you would add 4 mph to make the correction. We do not have to do that, which means that where the PEC says "add" our instruments are showing a higher value than in RL .  This is also why the stall IAS listed in the PN are a little lower than those in the BoS tech specs.  The PEC chart in the NASA test paper shows the same thing.

 

 

[Holtzauge]

Not at all surprised by the reactions to my post above but glad to see that at least some people have a sense of humour.

 

Anyway, regarding the Spitfire Mk9 cooling: I tried a climb yesterday at full WEP prophanging going as slow as I could (<100mph) up to 5000m and it did not overheat. But then neither does the messer: I did the same test in the Me-109 G14 with the same procedure and it did not overheat either. So it looks like something is off in the cooling modeling in both cases and I would not be surprised if this is adjusted quite soon.

[Kurfurst]

22 hours ago, Art-J said:

It's possible DCS went overboard with the radiators effectiveness in one direction, it's also possible that BoX went overboard in the other. That's what we might want to investigate.

 

The second radiator was there on MkVIII+ for a reason, but so were temp and speed limitations outlined in the PN.

 

DCS has a very sophisticated thermodynamics model from what I know of it. Its theremodynamics model goes as deep as calculating how much water goes through the engine, its heat transfer capacities and so on.

 

The second radiators was in fact replacing the one big coolant radiator (620x280x250) of the Mark V with two smaller coolant radiators (360/380 x 250 x 280) on the Mark IX, plus cramming the oil cooler and the intercooler radiator in the same place. Total coolant radiator surface slighthly increased, from 2950 dm2 on the Mark V to 3450 dm2 (plus 1150 dm2 intercooler) on the Mark IX

[Guest deleted@50488]

tSo... apparently I might not be that off in my initial post... It's probably the only kind of stuff ( this and flight dynamics ) that really calls my attention in a sim, together with other systems modelling, and although I did write based on my experience with another two sims, one civil and the other combat, the civil one using an add-on that was pricy and considered as top at it's time, I still find that indeed there is something lacking... 

 

Let's hope the devs can comment on it, and maybe fine tune it if they consider that there's some flaw in the way it's being presently modelled.

 

From a rw pilot perspective, I know it's very complex to model in a sim what we have IRL, and this applies even to rather "simple" aircraft models like the gliders I fly and sometimes try in sims and fail miserably to reproduce RL :-/… When I have that experience, and that's probably why I gave up using soaring sims at all, I think that probably even worst outcomes apply to much more complex models like these powerful and sometimes tricky ww2 props... I wonder how RW pilots trying it would evaluate it's adherence to the true characteristics of the aircrafts they fly for real, and I seriously hope that they can find it at least a bit better than I do the gliders I have tried in soaring sims ?

 

And thanks for ALL your contributions - I always learn something in this forum, being it technical, tactical, graphical or magical ?  and I also sometimes laugh when I read some well-humoured posts ? .

Edited June 2, 2018 by jcomm-in-combat

[Holtzauge]

But I think Condor is not to bad jcomm? Must say I find centering thermals and also doing aerotow with a c.g towhook not too far off from IRL. I used to work as a glider instructor and staying behind the towplane was one of the things some students had big problems with. If I had had Condor back them I'm sure it would have been much more easier for both them and me. Man, I remember some students: You would think they were trying to do aerobatics while on tow......

[Herne]

Would it be fair to say that you would expect the cooling performance to increase with altitude ? must be damn near impossible to overheat anything at > 30000' and < -50 degrees c 
 

Jcomm I agree with you in so far as I'd like to see all these war birds behave as accurately as possible, but I'd like it to be based on reliable data. If spitfire cooling was a problem in combat, i'm pretty sure there would have been pilot complaints to their superiors at the time that would have gone up the chain until they reached the manufacturers, and these problems would either have had to be addressed, or the military would invest in "better" planes.  Point being, there would be plenty of archived written evidence detailing the problems. I've looked, but I cant for the moment find any.

The Dev's from what I can tell do their own research, to model the aircraft characteristics as best they can. If you can find a reliable source saying that the merlin 66 / 70 had real problems with overheating on full boost in a vertical climb in a spitfire then they very likely would carefully consider it. I would be disappointed in the team though, if they were to make adjustments based only on how other games have modelled it.

[JtD]

27 minutes ago, =FEW=Herne said:

Would it be fair to say that you would expect the cooling performance to increase with altitude ?

 

Not, it would not - it depends on the temperature of the medium and the technology. You need a maximum of mass flow * temperature difference. While the lower outside temperature (higher temperature difference) and higher true air speed (higher mass flow) are beneficial, the lower pressure (lower boiling point for unpressurised water cooling systems -> lower temperature difference) and density of the air (lower mass flow) make things worse. You also need to factor in climate as such, hot weather makes flying at altitude more beneficial, on cold days best cooling may easily be provided down low. So, as every so often, the net result may vary. And this is without considering heat production of the engine, which also may vary over altitude.

 

As a ballpark, pressurized water cooling systems and oil coolers are relatively constant. Unpressurised water cooling systems and air cooled engines do worse at altitude.

Edited June 2, 2018 by JtD

[Holtzauge]

1 hour ago, =FEW=Herne said:

<snip>The Dev's from what I can tell do their own research, to model the aircraft characteristics as best they can. If you can find a reliable source saying that the merlin 66 / 70 had real problems with overheating on full boost in a vertical climb in a spitfire then they very likely would carefully consider it. I would be disappointed in the team though, if they were to make adjustments based only on how other games have modelled it.

 

But here is the dilemma isn’t it?: Comparisons to other sims is unavoidable and it’s pretty plain that when it comes to the Spitfire Mk9 cooling modelling then IL-2 and DCS are currently miles apart. So who is right? Both claim (and rightly so) that they are simulators but the difference in how the cooling is modeled is right now huge. IMHO this highlights the thing with simulators: They are simply models of reality which can be tuned and this is done continuously both by the DCS and Il-2 team. So maybe some who immediately pounce on any questioning of how things are modeled need to wind in their necks a bit and at least be open to the idea that things may not always be perfect and that while the current state of affairs may of course be due to the developers having access to some data we don’t it may also actually be due to that they have the wrong data or interpretation as a base and that things actually need to be tuned.

 

And even if there is data, which data is right? Obviously both the IL-2 team and DCS team are highly competent and both base their modelling on data yet they arrive at such different modelling. So maybe sometimes it makes sense to actually discuss things and reason instead of inanely shout “where is the data!” everytime. Whatever data you have needs to be interpreted and used in a sensible way and in many cases you will never get the exact data you want so you need to do sensible predictions based on what you have. This is equally applicable be it roll and aileron balancing or radiators and cooling efficiency that is the subject on hand.

 

Edit: Note that the inanely shouting for data was not directed at you Herne. When I wrote that I actually had some other colourful forum characters in mind.......

Edited June 2, 2018 by Holtzauge

[Herne]

3 minutes ago, Holtzauge said:

 

But here is the dilemma isn’t it?: Comparisons to other sims is unavoidable and it’s pretty plain that when it comes to the Spitfire Mk9 cooling modelling then IL-2 and DCS are currently miles apart. So who is right? Both claim (and rightly so) that they are simulators but the difference in how the cooling is modeled is right now huge. IMHO this highlights the thing with simulators: They are simply models of reality which can be tuned and this is done continuously both by the DCS and Il-2 team. So maybe some who immediately pounce on any questioning of how things are modeled need to wind in their necks a bit and at least be open to the idea that things may not always be perfect and that while the current state of affairs may of course be due to the developers having access to some data we don’t it may also actually be due to that they have the wrong data or interpretation as a base and that things actually need to be tuned.

 

And even if there is data, which data is right? Obviously both the IL-2 team and DCS team are highly competent and both base their modelling on data yet they arrive at such different modelling. So maybe sometimes it makes sense to actually discuss things and reason instead of inanely shout “where is the data!” everytime. Whatever data you have needs to be interpreted and used in a sensible way and in many cases you will never get the exact data you want so you need to do sensible predictions based on what you have. This is equally applicable be it roll and aileron balancing or radiators and cooling efficiency that is the subject on hand.

 

No argument here. 

 

In the absence of data though you have to do the best you can. And like you say sometimes data can be contradictory, but when it comes to cooling efficiency of the spit ix, I simply can't find any. Good or Bad. 

We have performance reports for the spit ix, and climb tests. If cooling was a problem during these tests, then the reports would have something to say about it. Pilots of the period would have moaned about it, written complaints /discussions between the RAF and the manufacturer would have documented it. We even now would readily be able to see / read evidence of it.

In the absence of any of this data pretty much the only option left to us, is to talk to pilots that fly these warbirds today, but even then, these old warbirds will never be pushed to their wartime ratings, not even close. So the dev's have to do the best that they can.

Thinking about it, if it was a known problem, wouldn't you expect to see some reference in the pilot notes ? something like "Be careful to keep an eye on your temperature while climbing vertically" ?

[Holtzauge]

Yes, and TBH my impression is that the overheating has historically been a bit overmodeled in general in flight sims from the very beginning. I would guess that IRL overheating is in general not much of a problem unless you are going really slow on a hot day with high boost. So the reason you don't have any pilot complaints is most likely due to them not going that slow and most likely not climbing at WEP for prolonged periods of time. What I do find strange though is the ability right now to climb the in-game Mk9 and G14 at speeds where you are hanging by the prop and  barely have roll control from SL to 5000 m at WEP without overheating.