Kurfürst

The only 109 that was tested in Britain with rudder Flettners was a nightfighter G-6 captured in 1944. The description of the aircraft controls regarding the rudder control is very brief, however, but in my read it does not seem to indicate particular control force issues at high speed, which OTOH they do note for the elevators etc. It says: "The rudder is fairly heavy but not uncomfortably so. As there is no rudder trimming device, it is necessary to apply right rudder for take-off and left rudder at high speeds. " So imho its good that they introduced rudder control forces to make this control feel more like that it acts against considerable force (and not presenting instant full deflections), and hopefully they won't overdo it and make it restrictive at high speed.

109E radiator assembly was rather different than the late 109G/K - the most important difference being the taller rudder w/o horn balance and the presence of Flettner assist tabs.

Great and very informative post Ark', but I think you would also need to look at the leg position, not just the seat position effect on g-tolerance.

Meaning that you can adjust them so that a short pilot couldn't reach them or...? I do not so how being adjustable is relevant to g-tolerance. Highmounted pedals/legs are beneficial to g-tolerance, so are laid back seats. It doesn't seem to be the 51 cockpit was designed with that in mind - but late in the war, they did have g-suits to improve upon that.

I am not sure Allied jocks would have it easier if we would have a G-14 or a G-14/AS instead of the K, given the prominence of low altitude combat and that the G-14 series are overall a bit better at these altitudes than the current lower-powered K-4 we have, expect in speed perhaps. A bit better climb, actually, and the MG 151/20 on the Gs is probably easier to use for most against fighters. In any case, the 51D was entering combat at about June 1944, before that and after that for a while you mostly had Bs and Cs around; and the K-4 in October/November 1944. There is just a couple of months of introduction between the two. Its not about as much as seat angle, rather than the position of the legs - pedals on the 109/190 are intentionally higher than on the 51.

Can be problematic from the animation, and more importantly, legal point of view - violence ratings go bizarrely high once you start to truthfully represent the interaction between 30 mm mine shells and furry furry cute animal internals. Which is why you neither have infantry, nor animals represented in sims. Even field gun's are usually operated exclusively by the 7. Panzer Division (aka the Ghost Division). In any case, if horses are in, I want Friesians.

Actually the "flammable" rep came from the poor ammo storage, and that even more was carried in practice . This improved a lot with the introduction of "wet" storage though. The reputation for all armor protection wasn't because the lack of thickness of the armor since the Sherman as you point out, (though early ones were inferior because of armor quality flaws and poor layout of that armor - it had many shot traps) was actually reasonably well armored for the time, but the fact that practically everything that shot at it could go right through it - which speaks rather more of the qualities of German PaKs and tank guns it faced rather than how poorly armored the Sherman was. relative to the guns it was supposed to protect from, it did a poor job at protecting the crew, and this puts even the 80 mm front hull of the panzervier in a much more favorable light, never mind the bigger, badder cats.. The M4, otoh, was poorly armed, with 3 inch variants coming too late and too few, Not that I have a great opinion of the Sherman as tank design, imo a much better tank could have been built, but its often gets a lot of unfair barrage. Especially as it costs money to build the models, so priority should be given to the "iconic" stuff, which not always translates to common though. Still, I can't get the excitement about it since its mostly just stuff that we shoot up on the ground, isn't it?

One of my personal favorites - the Sd_Kfz 234/2 Puma armored car. https://en.wikipedia.org/wiki/SdKfz_234

Even if we assume that the 109 pilot can't pull as much Gs at high speed as the P-51 pilot, it will be only true for instantenous turn rate since the "g-pull limit" advantage will be in speed regions which cannot be sustained on any prop job during manouvering. So its at best a very brief turn advantage before the speed bleeds down quickly. At high speeds sustained turn is so limited because of repidly increasing drag that any sustained turn will be marginal and unsuited for any combat manouver. The only possibility of having better high speed sustained turn is either lower parasitic drag and/or higher thrust - and the 51 certainly will not have higher thrust, since its engine is weaker, at all altitudes. Which leaves parasitic drag, where the 51 may have a very slight advantage or parity, the question is, whether it is enough to not only offset, but exceed the thrust advantage of the 109K... given the great similarity in top speeds, its may be just enough at lower altitudes for parity, but certainly not for greater excess thrust, especially not at altitude. Again, roughly the same physics apply and same power and drag characteristics are possessed at any but extreme high speeds near Vne, except that parasitic drag becomes less and less important, which is why the 109 turn advantage increases. Why? Aspect ratio, overall drag in turns (=less drag) high altititude propeller efficeny and engine output (=more thrust)...? High altitude is essentially analogous low speed turning environment. *Disclaimer! All numbers are rough estimates based on my personal experience with DCS and other simulations and many read books and articles.

I bit a of a side question, but why was fabric used/preferred so long for control surfaces? Even though many planes switched to light metal cover on some control surfaces when problems arose with balooning at high speed for example, but the industry standard remained fabric for a curiously long time... was there any inherent advantage to it, besides lightness?

Basically the numbers you on the chart above is the "nominal" speeds the aircraft, a sort of generic avarage, which the aircraft manufacturer guaranteed within certain range, typically within +/- 3%. When an aircraft was produced, it was put through short acceptance tests of a couple of minutes duration - those that did not meet the +/- 3% criteria were rejected and the manufacturer had to fix them up. For the 109K this means the manufactured planes had to achieve anywhere between ca. 690 and 730 km/h to be accepted for service. So, I agree with YoYo, the difference so small that that its mostly academic, as in real life there were large variations between individual planes... same goes for which plane was faster argument, when their "official" figures are just a few ten kilometer per hour away... ;)

At lower powers the speed difference should be roughly the same as at Sondernotleistung, ie. ca 10 km/h. The climb was the same with both props. In January 1945 they tested a K-4 with 4 different props, all at 1,35ata (so less than the DB/DC 30-min rating), the difference wasn't breathtaking, but noticable: 3-4 km/h at lower altitudes, and ca 10 km/h at VDH, between the ...159 and ...199 props.

You want others to disprove something that you cannot prove in the first place - that's not how it works - so it appears that it needs to be cleared up again that there weren't any widespread or in any sense standard use of +25 lbs on Spitfire IXs at all in 1944. The 'use' of +25 lbs was limited to just two Spitfire IX units, No. 1 and No. 165 Squadrons, i.e. 30-40 planes (with reserves - RAF Squadrons usually had a total of 20-22 planes, with 12/13 flyling and the rest being reserves) at best, out of 1000 or so IXLFs and even these two Squadrons were just there for doing trials to gain experience and fix defects like backfires, plug fouling etc. with the new boost and fuel. In the meanwhile, 95% of all the standard Spitfire IXs Squadrons in the ADFU and in the 2nd TAF, and everywhere else in the world at the same time were still using the standard +18 lbs boost or less. So what you wish for in fact is a very very rare bird in experimental stage. And although the 109K is not the subject of this thread, it appears you are ill-informed in thats plane operational use as well (see comments like never formed a Squadron etc.) - see the TOE for III/JG 77 for example, I see 75 109Ks arriving in October 1944, all the remaining G-14s being transferred to other units, making it a 'pure' *(and actually overstrenght) 109K Wing, with 4 full Squadrons of 109Ks. Or there is III. Wing of JG 26, with four Squadrons in total, which had 36 G-14s and 35 K-4s. Unless you are suggesting otherwise, I am going to presume the logical thing, that is that they were split up in the Wing as 2 Squadron of G-14s and 2 Squadron of K-4. I kinda agree about the balance thing, but since ED's stance so far was to have the most common/basic variant for 1944, I do not see why an exception would need to made with the Spit IX. That's why we have the P-51D with 67" and not 72" boost (although I think we should). That's why we have the 109K with 1.8ata and not 1.98ata boost (since it wasn't present yet in meaningful numbers in 1944, just as the IX at +25 lbs wasn't). The IX will be slow anyway, but will still easily outturn everybody else and climb very well. Nothing of that will change with +25 lbs either, except that Spitfire fanboys won't get the 'bestest' and rarest variant they always seem to wish for.

+25 psi = 81" in US boost terms and something like 2,76 ata in German terms. ;)

AFAIK we have DB 605DB engine modelled, which would mean the ata figures in manual are incorrect (or more precisly, they are for the DB 605DM engine variant). See:

IMO the stability curves from Germany and Russia for 109G are pretty conclusive evidence to that there should be a nose up trim neccesiating a push control by the pilot. It might have been intentional, i.e. if the pilot is uncouncious or unable to apply contant push on the stick, the plane will tend to go up and not down. Also, one of the pilot memoirs I have read (Lt. Tobak of RHAF) also tended to refer to when they were cruising (presumably high speed?) as 'nyomjuk' or 'we (are) push(ing) it'. The oral evidence would fit in nicely with a nose-up tendency, though could also translate to hitting the throttle or hasting the machine to a hurry.

Can you show something documenting this?

1. Original estimate for 2nd TAF's requirement (for the future) 15000 tons per month, that is, end of november 1944, see: http://www.wwiiaircraftperformance.org/150grade/100-150_Grade_Supply_23Nov44.pdf "Current requirements of 150 grade fuel and confined to the United Kingdom" - > no use of 150 grade and higher boost on the continent for the 2nd TAF as of end of November 1944. "As matters currently stand, the only organisation which will use 150 grade on the Continent is the 2nd TAF" - note future tense. 2. Actual consumption: http://www.wwiiaircraftperformance.org/150grade/theater_barrels_tons.html Consumption of 150 grade being 0 in 1944 for NW Europe (=2nd TAF). Then 2-2500 tons in January/February 1945, 7000 in March 1945, 12000 in April 1945 -> 150 grade / +25 lbs slowly being introduced from January 1945. Full introduction presumably not until late March/April 1945. Now present your evidence for widespread use of +25 lbs in Spitfire IX in 1944.

Nope, they began planning and accumulating fuel for storage in November 1944. The 2nd TAF did not use a single drop of 150 grade in 1944. None of the Spitfire Squadrons on D-Day were using +25 lbs in service - out of the ca. 30-40 Squadrons, only 2 (No 1 and 165 Sqn) were using +25 for operational trials, and very briefly, for V-1 busting opertions, and reverted in the automn of 1944. That 'only 1 Canadian Win that reverted' was appearantly also the only Wing we have evidence to have been using +25 lbs in March 1945. You could well say they that they all reverted. ;) Actual consumption of 150 grade fuel in the 2nd TAF begun on the very end of January 1945, though the records for the changeover are mostly from February-March 1945. So far there is only evidence of a 126 Wings changeover to 150 grade fuel, out of the 25-30 Spitfire IX/XVI Squadrons. There may or may have not been more, but the paper trail is missing. Also IIRC the 1650-7 was not entirely the same as the Merlin 66. If DCS wants to model a 126 Wing Spitfire IX at +25 lbs from March 1945, that's a totally valid choice, provided we allow for double standards and for a version completely ahistorical and atypical for 1944, since +25 was non existent in operational service at that time (as noted being limited to trials with two Squadrons, No. 1 and 165, which reverted to normal fuel after a couple of months and encountered some early backfiring troubles), and given that all other present prop jobs are "normal boost" versions. Its also an odd choice given that the P-51D was operating on 72" and and the K-4 on 1.98ata by that time, not the present 67" and 1.8" as present.

For 1944, Only two IX Squadrons actually, for operational trials. These two have reverted to 100/130 in the automn. The RAF basically used 150 grade in 1944 for anti-V1 operations only. It was not until 1945 when they started to switch over, but again they soon reverted back due to VE day and takeoff accidents caused by 150 grade.

The engine power should increase in itself and should be especially useful above rated altitude of the engine, since then the supercharger would be also driven faster. However the downside is that since there is a fixed reduction gear ratio to the propeller, its likely that the propeller blade tips will start to exceed the speed of sound (easy to calculate - RPM x reduction gear gives you the rotation speed of the prop, then consider the length of the prop blades - that is 3 meters on the 109 - and their speed of them at the tip ) above the permissible max rpm and the propeller efficiency will rapidly decrease. The end result is that while you pump a lot of power to turn the prop faster, it cannot turn that motion into useful thrust. Some of the early 109Es and Fs were officially allowed to briefly increase the engine rpm beyond max of 2400, to 2600 at high altitudes above the rated alt, which did yield some extra speed, however on the 109K this max speed was already 2800 and the only "increase of rpm" trick or allowance that can be found is for using the full rpm for lower boost settings. In any case, prolonged exceeding of allowed rpm will stress and break the engine components sooner or later, at which point power drops to zero. :)

Uhm, Il-2's K-4 was a true beast with 28-29 m/sec climb rate. And its no wonder if you get pessimistic figures for the K if you 'tune it' to the Kennblatt (sic!) figures, given that the Glc datasheet has the DM engined K-4, with much different (weaker) 30-min rating compared to the DCS one with almost 200 hp more..

As far as propellor effiency goes, I think that was taken into account for two reasons: one, they specifically wanted to compare the effect of the new 12199 propellor to the standard 12159 type, both of which were flight tested in a 109K at around the same time, albeit at lower power settings. Also the Mtt PB calculation specifically mentions that the difference between the standard/serial and project prop differences in level speed, but are (assumed to be?) equal in climb. Secondly, a few moths back the same Mtt PB did calculations for gondola equipped G-14 and G-14/ASM as well, the latter having the same 12159 type prop as the serial 109K, and it was calculated as being some ~1 m/sec slower in climb that the one with the previous 12087 prop. With the difference in weight and power between the two 109G types are otherwise negligable (if anything, the low/med alt G-14 had more drag due to the larger bulges), this must come down to the poorer low altitude/speed efficiency of the broad blade 12159 prop So in that test in all likelihood they calculated for the difference between the propellers efficiency for the 109K later on. Radiator drag seems is probably accounted for, since the radiator opening is also specified as half open until VDH, then slowly closing and I see no reason why to mention this if its not factored in. Since the effect of this on climb rate was very significant and have varied considerably with radiator opening and altitude, as directly evidenced by Mtt 109G flight trials in mid-1944 and further hinted by Finnish and British trials of G-2 - and for this reason should be carefully followed in any DCS proof test to obtain the same testing conditions. Exhaust and radiator jet thrust may have been not accounted for, I agree - this would also explain why there are so many Mtt climb calculations around for 109G that tend to yield lower climb rates than the actual flight tests! Also, I have yet to see any exhaust thrust figure for the DB 605 - the only one there is for the export 601Aa. It would be little wonder that they did not factor that in, if DB did not supply that to the engineer doing the calculations at Mtt PB, how is he supposed to do that without data...?

YoYo, Is it possible in your opinion that the Mtt Projektbüro calculations do not include exhaust thrust, as it appears to be the case in the Fw D9 calculations?

Indeed as IIRC the 109B had a sustained turn time of around 16 sec or so.