Kurfürst

The whole affair is not really related to Jumo 213 thread though... why not create seperate thread to discuss comparative advantages of planes etc.?

The original DB/DC manual of Dec 44 which the db/dc ratings are posted from was on white background - I simply turned it into inverse colour to fit into the site's design of black background. I am sure everyone is relieved now that we have cleared that important bit up. :D

Bf 109K-4 and K-6 performance at 1,98ata (2000PS) boost, DB 605DC powerplant. For relevant powers of DC powerplant at 1.98ata, see: http://kurfurst.org/Engine/DB60x/datasheets/DB605DC_limits_dec44Motorenkarte.jpg Level speeds (note: thick lines depict level speed with improved VDM 12 199 propellor. For perfromance with serial production VDM 12 159 propellor - or "Serienschrb", see thin lines). Climb rates Bf 109K-4 and K-6 performance at 1,88ata (1800/1850 PS) boost, DB 605DB powerplant. Level speeds (note: thick lines depict level speed with improved VDM 12 199 propellor. For perfromance with serial production VDM 12 159 propellor - or "Serienschrb", see thin lines). Climb rates : For relevant powers of DB powerplant at 1.80 ata boost, see: http://kurfurst.org/Engine/DB60x/datasheets/DB605DB_limits_dec44Motorenkarte.jpg Full report with English translation: http://kurfurst.org/Performance_tests/109K_PBLeistungen/Leist_109K_EN.html

There might be some overlook here - the paper from 13.10.44 you have kindly provided discusses the testing hydraulically actuated main/tail wheel on 109K. testing showed that the mainwheel could be operated up to 310 kph IAS w/o problem (if my German is correct, that is...) However another paper from 18.10.44 makes it clear that the idea of hydraulic operation of the mainwheel was dropped in favor of the much more simple and reliable mechanical actuation of the main wheel and tail wheel covers. IMHO there is little relation of the doc you posted on the main/tail wheel covers since the paper discusses essentially testing related to a different subject (the general deployment of the wheels which were hydraulically actuated) but has nothing to do with the wheel well covers (Restabdeckung) which were mechanically operated by the wheel itself. Hmm, interesting. The paper is unfortunately not entirely clearly worded, however its clear they preferred the "normal" elevator design as "better". I am puzzled however how and why the aileron / elevator combination is better or worse... Again very odd in view that WNF G-6s and indeed many G-10s are seen flying happily with aileron Flettner.. identification of 109K with aileron Flettner has been most difficult because of poor angles, rarity and quality of photographs, though one picture of a very late 109K suggest (too poor quality to make out detail 100%) the Flettner was eventually introduced sometime later. It is clear from documentation (see above) intitial ailerons were that of G-6. I am not sure if reason was aerodynamic or production related (existing stocks to be used first).

I do not know for the Spitfire, but 10:1 does not seem too optimistic, glide ratio for the 109E was 12:1. The Spitfire might do even better, given its lower wingloading, though AFAIK unlike the 109E, it did not have the ability to fully feather the prop.

Radiator cutoff system of 109K (in case of perforation of radiator). From Ersatzteiliste 109K, Rumpfwerk, Juli 1944.

A couple of interesting points for modelling from 109K-4 operating instructions (Bedienungsvorschrift) of October 1944 (published January 1945). Both the elevator trim and the elevator gear ratios were changed compared to 109G to make them lighter. The relevant parts have been marked with red rectangles. Translation: 3. Stabilisers and control surfaces Rudder without horn balance, with Flettner tabs. Rudder with reduced trailing edge" "Cantilever horizontal and adjustable tailplane; increased gearing compared to Bf 109 G." Mechanical indicator of the horizontal tailplane setting in the left wall of the cocpit" "To reduce stick forces, modified elevator control kinematics"

Correct. But some people just flame for sport. ;) I agree, in fact the whole planeset looks quite typical for late 1944 NW Europe, i.e. an "Ardennes map". Even if the initial planeset is very much out of the timeframe (really the only planes that seem right for Normandy is the Mark IX!) but lets not forget the other variant addons to be added later. Its also a question of modelling material. If a plane was very different from earlier, it was usually more tested, more manuals were made of it so its easier to model.

I wonder, if given the very complex nature of DCS engine models, it may be doable by simply setting higher manifold pressure to the engine model, and accurate power curves, heat models are then calculated automatically....? At least on Merlin engines, it seems the difference was rather straightforward - higher manifold pressure was allowed and full throttle, and more fuel was supplied. On other engines, like the dual version of 605DB/DC its not so straightforward, there was very likely much more serious changes in engine - timing, for example.

I agree. The WW2 DCS seems to cover the last year of the war (Normandy to VE day), during which some improvements were made to fighter aircraft performance, so you essentially have low boost and high boost versions for every one of them. I definietely hope so that both low/high versions would be modelled, but it thats too modelling time intensive, it would probably make more sense to make the low boost version, which is kinda represents the late 1944 period. After all, most of these planes were introduced from the 2nd half of 1944.

Will there be several variants of engine modelled in DCS? Will it be selectable, dependant on date, or there will be several models, like an 1945 version of Mark IX with +25? Standard boost was +18 through 1944 for Mark IX (only two Squadrons used + 25 for operational trials, not sure if they seen any combat during the trials). +25 lbs boost large(?) scale introduction into combat service was around February - March 1945 of 2nd TAF Spitfire units (ca 25 Squadrons were supposed to convert), though there were again some engine/150 grade fuel related fatal accidents at takeoff and the units concerned were soon switched back to 100 octane fuel to the relief of the pilots, which allowed the usual +18 lbs boost.

That is incorrect, the KTBs of the relevant unit leave no doubt about the use of 1,98ata engine settings.

Thanks! :) A flyable 109K modelled in great detail is just too tempting. :) Given that DCS, from what I hear tends to model every system (even ones that combat flight sims normally would not bother) it would be cool to see the duel purpose rear tank of the 109K (filled either with ca 80 liters MW or 115 liters of fuel). There was a switch in the canopy to select between the two purposes, as one would fill the contents of the light alloy rear tank into the fuel tank and the other into the eye of the supercharger. The switch could be turned to the bad position accidentally though, which was a complain from the units - generally, pressure-filling the fuel tank with water-methanol mixture was somewhat detrimental to engine life...

The D series engines were long a development, they evolved through times and so did their specs. The early ones (D/E/F) seems to have been an extension of the A/B/C starting out in 1942, but running on C-3 with marginally higher take off output of 1550 PS and rated altitude. Hence why the DB 605AM was originally designated DB 605G. I believe the D-2 series were based on these early series but with the larger supercharger of the 603A, as in the 605AS series. The early DM of 1800 PS output seems to be the D-2 with methnaol, hence DM. The manuals seem to only refer to C3 + MW operation, but given that this was the same on the AM engines, which was later eased and B4 + MW was allowed for in emergencies, I believe the case must have been similar in the case of the early DM too. The DB / DC interchangable series seems to be somewhat different, the DB was for either B4 or C3 (the latter was dropped without MW), but the DB could clearly operate on B4 + MW. The 1.8ata settings for the DB sans MW seems to have been dropped in early 1945. The DC was always using C3, either on 1,8 ata max boost settings (Grundeinstellung) or 1,98ata max boost settings. The available sources indicate that DB cleared 1.98ata in late 1944 without authorization from the RLM, and this was recalled until further testing in January 1945. II/JG 11 was performing operational trials to fix issues (which seem to be spark plug related) with the rating from February, while the 19 March 1945 order from Gen. Jagdflieger cleared the 1.98ata and ordered its use by (at least) four Me 109 Gruppen of JG 27 and 53, operating on the Western Front. There were several boost / fuel combinations, as seen in the late 1944 DB/DC manual, the relevant tables having been posted on my site: Regarding the 109K model, IMHO its very important to note that the aircraft had a major difference compared to the earlier G series: the elevator travel range was decreased, hence mechanical advantage of the pilot was increased, resulting in lessened elevator stick forces.