DCS Bf 109K-4

[9.JG27 DavidRed]

...watching the start up vid now in a loop, i have to say that flare gun is worse than expected. i really hope ED does listen and if its not already the case, that it can be removed soon.

[Kurfürst]

1.7 degrees is an inclination angle,yes?

 

Yes, I believe the text stands for SeitenLeitWerk Voreinstellung -1.7 degrees.

 

In the meantime I have found the F/K-series wing on which the wing profil is identified as 2414 (root) and 2411 (wingtip). It seems to be hand written note so it may be either someone's ex post facto guesswork or authentic...

 

I guess you would need a lot more cooling if you are running at high hp output like the K4's with MW 50 boost did so in those cases you would most likely need all the cooling you could get, at least on a hot summers day in the climb. So it seems strange to limit the radiator cooling performance.

 

However, could well be that they reduced the max opening in colder operating conditions. I guess it would make sense to have a smaller max opening in wintertime for example. As an analogy, in colder climates it is not unusual to cover up the radiator intake on your car in winter time to allow the engine to get up into suitable operating temperatures.

 

Apparantly not, the respective engine sheets of the DB 605A at 30-min rating (1310 PS output) and the methanol-water injected/boosted 605AM (same engine) for the wet WEP (MW50) rating of 1800 PS practically give the same cooling requirements of 340/345 000 kcal/h, despite the radically more power.

 

So in short the methanol boosted engine running at much higher output does not appear to need a lot more cooling at all. Probably a result of the internal cooling effects of methanol-water (MW 50 injection), but its curious why, given that the amount of water injected may not answer it alone.

 

Bottomline, if the above specs are true, the cooling capacity of the 109G was already generous for the 1,3ata rating as test show, so my guess would be that the radiator flap exit was limited in order to prevent the system from causing excessive drag, as 220 mm would be sufficient. Though cold winter conditions can explain as well the implementation of such measures.

 

BTW: Has there been any info on what boost the K4 is getting? I would assume it's the 1.8 ata we will see in DCS?

 

I believe its an early 1,8ata version which would be more representative for the late 1944 condition of 605DM and DB engines plus all the others seem to be the "normal" boosted versions. The '51 definietely is.

[Silver_Dragon]

kurfust, has some document show the operational remove of part of internal landing gear doors on field? some luftwafe photos show them removed, expose the gear tyres on combats operations, not bad can be put a option to show them with and without into DCS: W.

[Kurfürst]

Staying with the radiators - I noticed on the video that the radiator flap control seems wrong.

 

In DCS video, it has 4 positions (which is correct):

 

Automatisch (auto) - top position

Zu (close) - left position

Auf (open) - right position

Abgeschlossen (close) - lower position

 

The Abgeschlossen (closed) - lower position is wrong!

 

The real thing had label "Ruhe" (Still or in this context, Off) position in this place, which switched the motion of the radiator flaps off.

 

See the attched picture from the K-4 manual (K-4 Flugzeug-Handbuch Teil 00, P. 27), in which the Ruhe text can be faintly seen.

 

I believe the Zu and Auf positions were gradual and continous opening/closing the rad flaps to fully open or closed positions (I do not know how fast but probably slow). The pilot would leave the switch at these positions until the desired rad flap opening was achieved, and then turn the switch to "Ruhe" to fix them in that position.

 

Alternatively, he could leave it of course in the Automatic position and forget about the whole thing. :)

[Kurfürst]

kurfust, has some document show the operational remove of part of internal landing gear doors on field? some luftwafe photos show them removed, expose the gear tyres on combats operations, not bad can be put a option to show them with and without into DCS: W.

 

Nope, but it was already discussed in one of the K-4 topics iirc, it may be an issue with the mechanism or usual procedure of removing such part for winter conditions.

 

Personally, I like them on, otherwise you are pretty much flying a G-10 with an oddly placed radio access door...

[Kronos]

The Start Up looks great, however imo the DB605 sounds are terrible.

 

Compare the DCS sounds to this:

 

Of course the K4 doesn't have the A version, but the difference shouldn't be THAT big.

Edited November 30, 2014 by Kronos

[DB 605]

kurfust, has some document show the operational remove of part of internal landing gear doors on field? some luftwafe photos show them removed, expose the gear tyres on combats operations, not bad can be put a option to show them with and without into DCS: W.

 

Another theory is that they were never installed to all K4's, especially early ones. They were only installed when available, hence most of the later ones had them on. But who knows...

Edited November 30, 2014 by DB 605

[DB 605]

The Start Up looks great, however imo the DB605 sounds are terrible.

 

Compare the DCS sounds to this:

 

Of course the K4 doesn't have the A version, but the difference shouldn't be THAT big.

 

It's hard to say anything certain about engine sounds until we heard it revving, but idle may be at least too quiet...

 

Here's another onboard start-up video:

[Nate--IRL--]

The Start Up looks great, however imo the DB605 sounds are terrible.

 

Compare the DCS sounds to this:

 

Of course the K4 doesn't have the A version, but the difference shouldn't be THAT big.

 

That's a great recording.

 

Nate

[derelor]

Staying with the radiators - I noticed on the video that the radiator flap control seems wrong.

 

In DCS video, it has 4 positions (which is correct):

 

Automatisch (auto) - top position

Zu (close) - left position

Auf (open) - right position

Abgeschlossen (close) - lower position

 

The Abgeschlossen (closed) - lower position is wrong!

 

The real thing had label "Ruhe" (Still or in this context, Off) position in this place, which switched the motion of the radiator flaps off.

 

See the attched picture from the K-4 manual (K-4 Flugzeug-Handbuch Teil 00, P. 27), in which the Ruhe text can be faintly seen.

 

I believe the Zu and Auf positions were gradual and continous opening/closing the rad flaps to fully open or closed positions (I do not know how fast but probably slow). The pilot would leave the switch at these positions until the desired rad flap opening was achieved, and then turn the switch to "Ruhe" to fix them in that position.

 

Alternatively, he could leave it of course in the Automatic position and forget about the whole thing. :)

It says "Abgeschaltet" (OFF) and not "Abgeschlossen" (CLOSED). Does anyone have an image where the "Ruhe" position can be seen better?

[saurer]

It says "Abgeschaltet" (OFF) and not "Abgeschlossen" (CLOSED). Does anyone have an image where the "Ruhe" position can be seen better?

 

 

 

Here you can see it labeld "Ruhe", but it is not a K-4 but a G

[Kurfürst]

The best I can manage (from 109K service manual - Bedienungsvorschrift - Teil 2)

[derelor]

 

 

Here you can see it labeld "Ruhe", but it is not a K-4 but a G

Thanks, I also found this:

http://www.flugmuseum-messerschmitt.de/Me109G4/360Cockpit/

... but this G-4 has a very different cockpit. We should be 100% sure before reporting it. I am currently digging through some of my books...

 

Can anyone find out if the top position on a K-4 should read "Automatik" or "Automatisch"?

[derelor]

The best I can manage (from 109K service manual - Bedienungsvorschrift - Teil 2)

This is pretty good, thanks.

[Kurfürst]

Can anyone find out if the top position on a K-4 should read "Automatik" or "Automatisch"?

 

It should read "Automatik". Sorry for the typos in previous post, German is not my native language. However, the last K-4 cocpit pic should make the labels clear.

[Pilum]

Apparantly not, the respective engine sheets of the DB 605A at 30-min rating (1310 PS output) and the methanol-water injected/boosted 605AM (same engine) for the wet WEP (MW50) rating of 1800 PS practically give the same cooling requirements of 340/345 000 kcal/h, despite the radically more power.

 

So in short the methanol boosted engine running at much higher output does not appear to need a lot more cooling at all. Probably a result of the internal cooling effects of methanol-water (MW 50 injection), but its curious why, given that the amount of water injected may not answer it alone.

 

Bottomline, if the above specs are true, the cooling capacity of the 109G was already generous for the 1,3ata rating as test show, so my guess would be that the radiator flap exit was limited in order to prevent the system from causing excessive drag, as 220 mm would be sufficient. Though cold winter conditions can explain as well the implementation of such measures.

 

 

 

I believe its an early 1,8ata version which would be more representative for the late 1944 condition of 605DM and DB engines plus all the others seem to be the "normal" boosted versions. The '51 definietely is.

 

OK, that is interesting data but they are not the same engine really: The DB605A has a lower compression ratio and runs on B4 fuel while the DB605 AM has a higher compression ratio and runs on C3 fuel so thermodynamically they are different. That being said, it was interesting to see that there does not seem to be that much more power that needs to be cooled of when you compare these different engines and that if the radiator can handle the DB605A at 1310 Ps then it can of course most likely handle the 1800 Ps DB605AM.

 

But is DCS not modelling the Me109K4 with the DB605D 1.8 ata engine? For this version we do at least have solid kennblatt data: 1800 Ps S&N Leistung and 1275 Ps S&K Leistung with S&N Leistung giving 710 Km/h at 7.5 Km and 580 Km/h at sea level with the standard propeller. There is of course other K4 data but some of that is with a special thin bladed propeller and I would assume that DCS would model a K4 with a standard propeller? Anyway, I guess we will see that on Wednesday.

[JST]

From product page 3:

 

The DCS Bf 109 K-4 is modeled with the DB 605 DB engine.

 

 

The DB 605 DB could use B4 fuel which, with MW 50 Methanol Water injection equipment, generated an emergency power rating of 1,600 PS at 6,000 m (1,160 PS maximum continual at 6,600 m), and take-off power of 1,850 PS at 0 m, with a maximum supercharger boost of 1.8 ATA. The DB could also be run on higher octane C3 fuel, but use of MW 50 was forbidden.

[Kurfürst]

OK, that is interesting data but they are not the same engine really: The DB605A has a lower compression ratio and runs on B4 fuel while the DB605 AM has a higher compression ratio and runs on C3 fuel so thermodynamically they are different. That being said, it was interesting to see that there does not seem to be that much more power that needs to be cooled of when you compare these different engines and that if the radiator can handle the DB605A at 1310 Ps then it can of course most likely handle the 1800 Ps DB605AM.

 

That the cooling system could handle the MW boosted output the same as the 100% Kampfleistung rating was confirmed by Messerschmitt tests in July 1944. During climbs to 6000m the radiator suitability (Gütegrad) of the 109G was 0,95 with 100% (i.e. 30 min unboosted) rating and 0,96 with 1,75ata and MW injection. Oil suitability seems to be the same even though the oil heating was more pronounced with higher boosts (hence why larger oil coolers on later 109s).

 

But is DCS not modelling the Me109K4 with the DB605D 1.8 ata engine? For this version we do at least have solid kennblatt data: 1800 Ps S&N Leistung and 1275 Ps S&K Leistung with S&N Leistung giving 710 Km/h at 7.5 Km and 580 Km/h at sea level with the standard propeller. There is of course other K4 data but some of that is with a special thin bladed propeller and I would assume that DCS would model a K4 with a standard propeller? Anyway, I guess we will see that on Wednesday.

 

Figures you posted are for the DM engine model and are significantly simplified in GLC datasheets.

 

The correct data for 109K-4 with 1,8ata DB 605DB, standard propeller (VDM 12159) are

595 km/h top speed at SL,

710 km/h at 7500 m

22,1-22,4 m/sec max climb rate near SL

 

as show by the following Mtt speed and climb graphs.

 

http://kurfurst.org/Performance_tests/109K_PBLeistungen/files/5026-27_DBSonder_MW_geschw.jpg

http://kurfurst.org/Performance_tests/109K_PBLeistungen/files/5026_28_DBSonder_MW_steig.jpg

 

The climb is understood with radiator flaps in climb position, that is apparantly the max. 220 mm opening, so they can be improved significantly, especially at altitude by closing the radiators. Perhaps thats why they were limited to 220 m/m on 109K examples - the automatics would otherwise tend to open them up too greatly even if the temperuteres were just a few degrees above the ideal ones, and stil far below max. permissable. It would be interesting to know if the 109K kühlerklappe kinematics differed from the G series, and if they shared the same radiator.

Edited November 30, 2014 by Kurfürst

[Pilum]

From product page 3:

 

The DCS Bf 109 K-4 is modeled with the DB 605 DB engine.

 

 

The DB 605 DB could use B4 fuel which, with MW 50 Methanol Water injection equipment, generated an emergency power rating of 1,600 PS at 6,000 m (1,160 PS maximum continual at 6,600 m), and take-off power of 1,850 PS at 0 m, with a maximum supercharger boost of 1.8 ATA. The DB could also be run on higher octane C3 fuel, but use of MW 50 was forbidden.

 

 

OK, thanks for that. Should have RTFM before posting :doh:

[mikiintruder]

https://www.youtube.com/watch?v=spOlkk205Qk

 

https://www.youtube.com/watch?v=k85-HYbvfNE

 

:pilotfly:

[Pilum]

 

Figures you posted are for the DM engine model and are significantly simplified in GLC datasheets.

 

The correct data for 109K-4 with 1,8ata DB 605DB, standard propeller (VDM 12159) are

595 km/h top speed at SL,

710 km/h at 7500 m

22,1-22,4 m/sec max climb rate near SL

 

as show by the following Mtt speed and climb graphs.

 

http://kurfurst.org/Performance_tests/109K_PBLeistungen/files/5026-27_DBSonder_MW_geschw.jpg

http://kurfurst.org/Performance_tests/109K_PBLeistungen/files/5026_28_DBSonder_MW_steig.jpg

 

The climb is understood with radiator flaps in climb position, that is apparantly the max. 220 mm opening, so they can be improved significantly, especially at altitude by closing the radiators. Perhaps thats why they were limited to 220 m/m on 109K examples - the automatics would otherwise tend to open them up too greatly even if the temperuteres were just a few degrees above the ideal ones, and stil far below max. permissable. It would be interesting to know if the 109K kühlerklappe kinematics differed from the G series, and if they shared the same radiator.

 

Blanket statements claiming some data to be the "correct data" and the other data as "significantly simplified need to be backed up by evidence. AFAIK German Kennblatt figures are reliable but if there is evidence to the contrary then I'm willing to change my mind. Also, on what evidence does the claim it is "understood" that the climb was done under certain conditions meaning they "can be improved significantly" rest?

 

Anyway, It's up to DCS to judge if they rather trust the kennblatt figure of 580 Km/h or if they want to use your figure of 595 Km/h. I suppose they have both datasheets. Seeing you are advocating 595 Km/h Kurfurst, I'm sure there is no higher figure around for the K4 so it's always good to know what value the top outlier has. ;)

[Kurfürst]

What are the conditions for these Kennblatt figures? What engine, what flying weight, what boost, what corrections, how many data points...? Simple fact is that the numbers you wish for are for an earlier DM-series engine. In contrast we will have the more powerful DB-series engined 109K, for which the detailed and reliable figures I just posted are readily available. Anyway, its a moot point as this matter must have been already decided, thankfully without the slightest need to refer to any homebrewn random generator. ;)

Edited November 30, 2014 by Kurfürst

[Pilum]

What are the conditions for these Kennblatt figures? What engine, what flying weight, what boost, what corrections, how many data points...? Simple fact is that the numbers you wish for are for an earlier DM-series engine. In contrast we will have the more powerful DB-series engined 109K, for which the detailed and reliable figures I just posted are readily available. Anyway, its a moot point as this matter must have been already decided, thankfully without the slightest need to refer to any homebrewn random generator. ;)

 

I think you lost track of the fact that the onus is on you to come up with the evidence: Kennblatts were used by the Germans themselves to summarize the key characteristics for their aircraft so I'm more inclined to believe them and the attached Kennblatt rather than some cherrypicked top end outlier you found in a test report with unknown provenance.

Edited November 30, 2014 by NineLine
Rule 1.1 violations

[Kurfürst]

Same old, same old... there is nothing wrong the GLC sheet of course, expect it shows simplified figures of unknown conditions for the wrong engine. Wave it about as much as you like.

 

As for the data I have posted, it is for known aiframe conditions (that match DCS K-4, including that it is for the right engine, DB 605DB) and explicitely state that they are conservative figures that are certainly going to bereached.

 

See: http://kurfurst.org/Performance_tests/109K_PBLeistungen/Leist_109K_EN.html

 

Condition of the aircraft :

 

8-109 K4 G = 3400 kg

Retractable tailwheel. streamlined MG 131 bulges, wheel well covers,streamlined mainwheel bulges, for tire 660 x 190; without antenna mast, with FuG 25 aerial, FuG 16ZY aerial, D.F. loop, MW 50 system, without wing weapons.

 

[...]

 

Mach effects: Were not taken into account in the calculation. Greatest deviation at the Volldruckhöhe with Sondernotleistung, ~5 km/h.

 

Notes : The stated performance figures are going to be reached with well-built serial production machines for certain. No specials were included in the calculations; improvements as in the case of Leistungsmaschine I., such as improved surface finish through special threatment to the airframe and surface protective layer on the wing and on the propeller, improved radiator passthrough, symmetrical ailerons, by which an additional ca. 12km/h gain in level flight can be expected. This 12 km/h will be only added to the calculations, if the abovementioned measures can be actually materialized for series production.

Edited November 30, 2014 by Kurfürst
Clarify conditions for posted performance data, with source

[Friedrich-4B]

Notes : The stated performance figures are going to be reached with well-built serial production machines for certain. No specials were included in the calculations; improvements as in the case of Leistungsmaschine I., such as improved surface finish through special threatment to the airframe and surface protective layer on the wing and on the propeller, improved radiator passthrough, symmetrical ailerons, by which an additional ca. 12km/h gain in level flight can be expected. This 12 km/h will be only added to the calculations, if the abovementioned measures can be actually materialized for series production.[/i]

 

Note the highly provisional statements about

well-built serial production machines

 

or

 

This 12 km/h will be only added to the calculations, if the abovementioned measures can be actually materialized for series production.

 

It is highly doubtful that the "special treatments" were ever adopted on the production lines at Regensburg, considering the poor construction standards that prevailed: eg; from Nest of Eagles . More often than not, the units receiving the new-built K-4s had to spend a great deal of time just rectifying mechanical faults and/or sabotage, let alone wasting even more time trying to apply special finishes. As it is, there was only enough fuel for a 15 minute flight test.

 

Plus, the MK 108s suffered from jams because of poorly insulated fuses.

 

 

What we can expect, from the data provided by ED, is a well maintained, reasonably well finished, K-4 running at 1.8 ata.

 

http://www.digitalcombatsimulator.com/en/products/kurfurst/

 

Using MW 50 and maximum boost the Bf 109 K-4 was the fastest 109 of World War II, reaching a maximum speed of 710 km/h (440 mph) at 7,500 m (24,610 ft.) altitude. Without MW 50 and using 1.80 ATA the K-4 reached 670 km/h (416 mph) at 9,000 m (26,528 ft). The Initial Rate of climb was 2,775 ft. (850 m)/min, without MW 50, and 3,563 ft. (1,090 m)/min, using MW 50.

Edited December 1, 2014 by Friedrich-4/B