Kurfürst

109s only had the inertia starter, there was an option for the 605s to use an electric starter motor, but 109s did not have it. It could be a weight or space issue - maybe the cowl MGs and their ammunition boxes got in the way?

Either the exhaust had back pressure problems (they seem to have encountered this a couple of times with the Merlin), or perhaps they wanted to have minimal glare for night flying, as this was IIRC a compain with the proto-Spit. I would say that someone at Supermarine had a bad case of exhaust stub fetish, as they ended up with a perfectly ordinary one fitted in the end.

I wonder how much of that 6 mph speed increase with the NACA style exhaust compared to the original stubs by Supermarine was due to simply not having a large chunk of metal sticking out left and right of the engine. :lol:

Lets see the originals and I think you are guessing about the boost, since it cannot match +15 lbs data.

I wonder why that Janus face of the Jumo 213A exist. The first graph by Crumpp has definite MW-50 injection, and slightly higher powers, the second one from YoYo is from AIR 40/74 series does not note MW-50 and has very slightly higher altitude ratings, but lower low altitude ratings. My take is that the second Jumo 213A graph is actually for the increased compression ratio version of the Jumo 213A, with C-3 fuel but no MW-50 which was probably not used in the end for serial production.

I will take a good look.. certainly not direct power graphs I can recall, but sometimes such data may be hidden amongst other papers on different subject. Also, thank you for your time you have put into trying to explain things on Dora 9 flight model.

Scroll back a couple of pages ;) - never mind, let me do it for ya.

In my experience, many of these calculations were just quick and dirty estimates to get an idea of the feasibility of installing a certain engine or using a certain configuration. It was cheaper than actually spending money of building prototypes. How much will it be faster with a certain increase in power? Which one will be better at high altitudes for bomber interception, one existing design in production if we add extra weapons, or a new design in standard config? Often preliminary questions like this had to be answered with some rough estimate before proceeding. Plus, it was often made by the same guys working on the project, so many times not all data was recorded, as everyone knew that for example that the No. 6. plane had a missing intake or another non-standard feature - things that you can only figure out when your read between the lines of other reports. They are also riddled with typos - the 109G's Rechlin datasheet for example lists 10 km/h higher speed at an altitude due to a typo, and you have to cross-check it with the corresponding speed graph to find this error, and there is one Messerschmitt AG document at the 'Lair that uses both Bf and Me for the 109 in the same document...! Not to mention the atmospheric and testing standards varied from company to company, nation to nation. The British usually gave speed figures for 95% load, the Germans for 100%, for example. British Standard Summer was different from German Standard Summer, or Soviet Standard Summer etc. Direct comparison is often meaningless without some brain work on these things first...

Stick for per g is pretty much constant unless you get near 1 Mach. This quality also saves you from dynamic stalls though. I guess when the WW2 Plane Planned Second comes to DCS, many will appreciate this stick behavior. ;)

:thumbup: Spared me a warn point, too. :music_whistling:

How? The pump is at the bottom of the tank. If the tank is not topped with fuel, I would reason the fuel go to the top of the tank during inverted or negative g flight, and pump cannot reach it. The only fuel being fed to the engine would be the fuel left in the pipelines - which would run out after a couple of seconds. In a loop you have positive g load applied so the fuel would go to the bottom of the tank, and thus reachable by the pumps.

Well, basically I agree with that - I think wing breaks is the worst part of the FM currently. Something is simply off. But there are a lot of improvements in other areas. Its not perfect yet, no. But already the best - given that AFAIK only Aces High ( :megalol: ), some MS FS modules (:doh: ) and the old Il-2 models the K-4 (which was wrong in several places, like overheat, altitude model, 3d model etc. and far more simple FM). When I take up the DCS K-4, it feels real. And its the only one that kills you in the ground already if you go easy on her for a second. The fuel pressure thing is annoying to be sure and I wonder what causes it - all fuel forced to the top of the tank but no accounting for that there may be enough left in the bottom to still the reach the pumps..? An explanation would help, I certainly do not know of such thing happening, but with a complex system modelling as in DCS, it might be some odd coincidence in the systems. Elevator trim, it seems odd but the stability tests seem to support it, as do some vague comments from WW2 pilots. Given I have seen nothing to contradict it, I guess I can't say its wrong. Wing drop - slats to dot prevent one wing stalling, maybe its a slideslip (pilot) issue. I had no issues in maintaining her in very tight turn though, its much easier than in the early builds. Spins, flats the real thing was extremely unlikely go into one and in the admittedly very little time I was able to spend in the virtual aircraft, I did not encounter it. The wings always broke first. :D I am satisfied with the overall quality. Very much so. Quite frankly if the thing would still have all the bugs I would still enjoy it, because the DCS module flies, takes off and lands so realistically or at least close, than nothing else in any other sim. The thing flies much like as I would expect the real aircraft to fly. Its an absolute performance beast, good handling yet it has some yaw instability both on the ground and in the air. Engine management is a piece of cake, as on all LW aircraft. speed specs seem to be fine, I did not try climb so much because its difficult the accurately measure and I did not have time. If I have a serious issues with something its the netcode of the multiplayer module - there are no words for it. The SP module is fully fliud with high FPS, the same thing in MP often turns into slideshow. And yes the engine should stop in inverted flight. The 109 fuel system was not prepeared for inverted flight, the fuel would go into the top of the fuel tank, and there was no fuel pump there -> fuel starvation in a matter of seconds. One restored 109 even suffered an engine stop due to that recently. Its also specifically mentioned in 109 manuals that prolonged inverted flights are not possible (why would anyone need to do that?), though I suppose it might be possible if you are pulling g-load during that phase.

Given from what I have tried even at high speed you can still pull 5-6 gs I don't think it matters so much. Yes the stick and the elevator control surfaces move less but they also have more effect, and frankly pulling more would only result in blackouts and bent/broken wings. The only real limitation is the ailerons, because you cannot displace them fully your roll rate, which is avarage to start with, suffers and you can only do slow rolls. That's the only practical limitation you have to live with.

... and to add to that, there is even coolant radiator thrust (cold air entering into the radiator, warms up, expands, leaves at the back creating some pressure). Its basically a miniature jet engine, only here you do not heat up the air by burning fuel but by cirvulating hot fluid in the radiator. Of course its not that great thrust, but its still thrust and at high speed, where the propeller starts to struggle to convert its motion into thrust it can be more significant and at the very least, it makes up at least some of the drag the radiator system creates. On some designs, such as the P-51 its even claimed to provide a net positive thrust. Though this is debated back and forth, it still shows that how important careful designing of the radiators were to the overall design. There are a few engine charts that show this effect - this one is for the DB 601Aa series, the top line showing the equivalent horsepower of the engine output PLUS the exhaust thrust at 600 km/h. It IS a significant boost, adding the equivalent of about 100 horsepower due to exhaust thrust (Rückstossenergie). Out of interest, this power curve also shows the effect rammed power (Stau, Staudruck on the right, given at different pressures, equivalent to specific speeds/atmoshpeheric conditions). When the airplane travels very fast, it slams a lot of extra air into the supercharger air intake - in effect, its own motion provides a lot of "free" supercharging. That is why aircraft higher rated altitudes at high speed compared to slow speed climbing conditions.

I really don't like these wear signs and scratches all over the place in any 3d canopy... the lifespan of these fighter aircraft, especially for late LW fighters was incredibly short, a few dozen hours at best. There was simply no time to get all those scratches.

I agree with the OP. I didn't try the 109K much since the original beta release, letting the team to fix the betas teething problems first. I did try it in the weekend, and oh boy. I love the stick force implementation. It feels real, it feels very like thereal 109 from what I have read in the accounts, the stick really gets limited at high speeds, but you can still pull respectable g-loads with it and it seems to me, though no precise measurements were made the rolling speeds are also neatly modeled. I did just a few brief trials runs to check the speeds at SL and at rated altitude, and it seems very close to the real thing's specs for this particular boost of 1.8ata, given imperfections in the flying, wind etc. Radiator kinematics also seemed to work nicely, and take off, landing gear interaction with the ground also seem to have improved greatly - no sudden jumps to one side or another, and it can be taken off with relative easy if you pay attention to what you are doing. If you do not, the plane still goes medieval on you in a most brutal way, just as it should. The only thing that made an annoying reappearance is the tendency of the wings to come of at 6-7 gs. This is still needs to be fixed, or at least, explained. Even at this early stage its flat out the best 109 FM I have ever seen. No gamey mechanics, no overdone flight qualities to match anecdotes for even the blind and deaf to hear and see, the physics are believable and seem to work right to our real life expectation of how real world objects would behave. In short, well done, Yo Yo and thank you for all your work that has been put into this wonderful K-4 ! :thumbup:

Quick and dirty of course and I am missing the boosted output of the BMW 801 here (2100 PS at SL IIRC), whereas the Jumo curve is for full boost, with MW -50. The normal output was around 1770 PS. At lower altitudes there is some advantage of the 213 of course, largely due to its more efficient supercharger handling (no see-saw curve), which should show itself between 2-4 km range mostly... However it is seen that actually above rated altitude, ie. 6000+ m for both engines, the two engines are almost perform the same, despite the common myth that the Jumo 213 somehow improved the poor altitude performance of the BMW 801D. It simply didn't, where it improved over it was the much smaller cross setion and smaller drag of the engine installation. So at least at higher altitude practically all of the performance increase is due to the lower drag of the D-9 compared to the A airframe IMO. EDIT: Added a rough estimate of C-3 injection boosted BMW 801 power levels

I think YoYo already answered you that one - the Fw calculations of 22 m/sec do not take into account the exhaust thrust of the engine, moreover they are for an aircraft with an ETC bomb rack, so it has quite a bit more drag than a clean aircraft. Essentially most of the performance increase of the Dora was due to its much smaller drag compared to the A-series, think about that.

I do wonder if we really need medium bombers, if medium would fit well into a DCS scenario. First of all, medium bombers were very complex machines, with lots on board systems that would very work intensive to model on the fidelity levels DCS usually offers. They are also probably a niche, thats probably why you have so few really detailed bomber sims. Bomber tactics were also rather rigid, you had a pre planned flight path and target, which you had to stick to. It was usually designed to avoid flak and fighters, against which the bombers were sitting ducks basically. In short, flying a medium bomber would be rather similar imho to flying a 747 in MS Flight Simulator (boring, at least for me), and not very rewarding in multiplayer, unless you can spare the time and have a dozen friends who would fly with you in a formation on a server, spending half an hour just to get into flak safe altitude... Even then, with the density of fighters and interceptors on a server, you are almost sure to run into some of them, and given the great superiority of a fighter over a bomber, its not really a question wheter the fighter would shoot you down, its more a matter of flipping of coin as to who would get shot down of the bomber guys. It would be as much fun as playing the Zebras in a Lion sim.. IMHO faster, more agile light bombers are so much more appropriate for a multiplayer simulation. They give you a fighting chance, more chance to actually reaching the target and doing something the fighters can't.

That pretty much clears the issue up. :thumbup:

I suppose "on hand" would include the ones in storage/reserve..?

Well the thing is that by the time 150 grade fuel was introduced into the 8th AAF Fighter Command, the only US formation to use that fuel in Europe, there weren't many P-47 Fighter Groups left, and even those converted to Mustangs soon enough. Same goes to the P-38. The 15th AAF may have still had a plenty of these two older types, but the 15th AAF did not get 150 grade supply at all. By the time the D-9s and K-4 were arriving in the field (or air), there were only four P-47 Fighter Groups left for escort, which number was halved to just two by December.

I can only see you being insistent on Allied aircraft should be always based on higher-end examples... :music_whistling:

IIRC the Soviet trial of the captured 109G-2 Yo Yo has possibly used to get some idea on the trimming characteristics of the 109K has a picture of the "clean" 3-gun (no gondies) 109G-2 the Soviet forces have captured. There was also another G-2 in five gun condition (gondies) but that was not the subject of the Soviet stability report. Its a bit difficult for me to make sense of the all Cyrillic report though, but if I have decoded it right it does shows a nose up tendency in all trim conditions and centre of gravity. I do find it odd that the plane allagedly can't (?) be trimmed to level flight but it seems thats what the report says... Or maybe we are missing something.

There were some 1600 K-4s and iirc 1800 D-9s produced, yet we still try to argue how 'uncommon' they were, huh? That's more than all the D-30s if saburos numbers are correct. Apparently, that one unit of P-47s may have been running on high grade with the 8th AAF, all others running with low grade in the 9th AAF - and so suddenly the logic and standard turns upside down and its that we need the high grade variant for whatever reason.. Given the evidence, a good case could be made for the P-51D for higher grade fuels but quite obviously that's not the case for the P-47D. Or another I shall not mention.