Kurfürst

So are you claiming that you have never, ever seen the evidence for these technical troubles and fatal accidents? http://en.wikipedia.org/wiki/Chewbacca_defense Where is the evidence that the SINGLE XIV Wing that were supposed to use +21 lbs boost ever made the transition? Nor has any evidence ever been supplied that of this single XIV Wing of the 2nd TAF ever used higher boost on operations. Nor for the single or two Mark IX Wing for that matter. There is not a single combat account of a XIV or IX pilot ever mentioning the use of high boost against an enemy aircraft. Of course there may be some still. Its just not found yet... in like, 15 years of desperate search. :P Note that nobody probably ever saw German pilots recalling boost ratings ever (which would probably made little sense to do so for them with the automatic controls), so if you go by that, I suppose this proves German pilots never used anything higher than 1 ata. Oh wait, that's obvious rubbish. Note that half of IX Wing did make some operational trials of +25 lbs in late 1944, too. Apparently, they never saw any combat. Interesting claim, without a source. Yeah I guess they just spent the rest of the war taking a nap. :D III./JG 27 bases: 18.3.45 - 29.3.45Gütersloh Bf 109K 29.3.45 - 8.4.45 Goslar Bf 109K 8.4.45 - 11.4.45 Halberstadt Bf 109K 11.4.45 - 4.45 Grossenhain Bf 109K 4.45 - 20.4.45 Prague-Gbell Bf 109K 20.4.45 - 2.5.45 Bad Aibling Bf 109K 2.5.45 - 5.45 Salzburg Bf 109K 5.45 - 8.5.45 Saalbach Bf 109K And in all that time, they weren't shooting down a single aircraft, being one of the four main 109 Gruppen of the West. :megalol: Nope, it four Gruppen with a strenght of about 150 109s in strenght (which were moving up and down of course - the normal established strenght for four 1944 LW fighter Gruppen would be about 270 aircraft) , which were ALL the Bf 109s remaining in the Western front by the Spring of 1945. The rest were on the eastern front. Thing is, in the Spring of 1945, if you met a 109K in Western front in the late March - April May of 1945, it was to be a fully rated (1.98 ata) one.

Well that's probably because Mike's articles is full of... issues. ;) More like March 1944 and October 1944. The January 1944 "introduction" of the XIV amounted little more than someone at the Air Ministry writing down XIV next to a Squadrons with a pencil. There is a world of difference between that and service introduction though. At this point most of the RAF's Spitfire Sqds were still equipped with.... the Mark V, they just started to introduce the Mark IX in numbers. Spitfires always seem to take a lot of time between someone designating a Sqn as a XIV Squadron on paper in January, but with the very slow pace of production it took them months to fully equip even a couple of Sqns with the new Mark and re-train to it. As for operational engagements (save V-1s), they are virtually absent until the automn when the XIV Squadrons were slowly transferred to the continent but were thus stripped of 150 grade supplies, only available in the UK (and ironically, largely restricted to the USAAF). The first three XIV Sqns weren't wheels down on the continent (foul flying weather was also responsible) until October-November IIRC. After that, together with Tempests they did took a lion's share from the RAF's 2nd TAF's a-2-a kills, but until that, IMO their results of shooting down (manned) LW were so utterly marginal that it doesn't even worth mentioning in the shadow of the bloodletting between the USAAF and LW in the same period. Until the end of 1944, only about 300 XIVs were produced against some 856 K-4s (which started only in September but at a much higher pace). So as far as operational combat aircraft engaging in air combat, they were, for all practical purposes, appearing at the very same time. As noted above, they were combat contemporaries for all practical reasons. Combat debut in numbers came at exactly the same time, in the autumn of 1944. No, what would be fair would be to compare the 18lbs Spit IX with almost one-and-a-half year later's K4, because that's what was facing each other in the automn of 1944 mostly. And well, of course, the MW boosted G models. No, of course if it was a Dec 31st plane its not a 1944 plane. Thing is, the K-4 came into service with units in the West in October 1944, and in very considerable numbers. Some 150 - 200 were delivered in October already, and frontline strenght was a steady 200 in the last months of 1944. The first known losses are end of october/start of November, I strongly believe the first actual bloodletting was during the huge (and very pricey) 2nd November engagement. Uhm, the XIVs so called combat history (as far as against manned aircraft go, as they DID shot down some 300 V-1s, for which the people of London were very thankful) until the autumn of 1944 is virtually non existent. One Ju 88 claimed to be shot down, really? What else - perhaps a Storch too in 9 months? Absolutely occasional shotdowns, uneventful patrols over England and in safe zones, that does not read as a frontline fighter to me. The two British boosted Mustang III Squadrons were operatially marginal as well. Their highlight was the single combat when they managed to surprise JG 26 (? IIRC) during take off (Mike's site can be economical with the details, isnt't it) and shot down a good number of aircraft from advantage. Then pretty much nothing. The other Mustang Sqn one spent all its time over the North Sea for some obscure reason, meeting enemy aircraft only once I believe, maybe scoring success even that single time. Good news :) Its a little price though. K-4s were in very active service in significant numbers in late 1944, about as large as Tempests and XIVs combined in fact. Neither the XIV or the Tempest saw much anti-air action until "very late 1944 and 1945 spring" either, so that makes them contemporaries in my book. Also, before February-March 1945 neither IXs, XIVs had run on higher boost than +18 with the 2nd TAF. They did not have the fuel for it, as 150 grade was in short supply and was needed by the USAAF. The first clues of the changeover to 150 grade and associated higher turn up at this point. Coincidentally, that is also the exact same period when fully rated (1.98ata, 2000 PS using the German equivalent of 150 grade fuel, the Green C-3 type) K-4s were also cleared and began converting for the high boost. So in short, either you have a pre spring 1945 scenario with lower boosted models (+18 lbs IXs, 1.8ata K-4), or you have spring 1945 scenario with higher boosted models (+25 lbs IXs, 1.98ata K-4 etc.). I believe though, given the Normandy map and all, that the scenario is a late 1944 one, so, no higher boosted models. I'd love to have those latter though, as otherwise the standard +18 lbs Niners really stand very little chance against these late war aircraft that they historically faced.

The problem is that isnát a late 1944 match... its a spring 1945 "match". The +25 lbs Spit IXs were only used for trials by two Squadrons in 1944, and its somewhat doubtful if they see much if any combat. Some technical troubles like backfires were encountered, but were supposedly solved. In any case, those two Sqns were the only ones for 1944. A wider scale of operational use for ca. 25 Sqds of IXs from the 2nd TAF on the continent was stipulated at the end of 1944, but it took about mid-late February that the changeover actually took place. Again, some techical troubles with the engines occured, with engines stopping at take off and some lethal accidents. So basically the vast majority of late 1944 IXs were running on +18, ie. 1943 levels of boost and performance. Ditto for Mark XIVs, they ran on +18 in late 1944, when they were gradually transferred to the continent, as the 2nd TAF did not have 150 grade fuel that was needed for higher boosts. The K-4 was introduced in November 1944, with lower boost most of the time (1,75/1,8ata), and higher boost was approved for all Western 109K Wings in about March 1945, at the same time when bits of +21 boosted XIVs turn up. So, for a late 1944 setup, for the most typical aircraft matches, you would need +18 lbs IXs (and XIV, if they would be modelled) and 1,8ata 109Ks, and 71" (or 75") P-51s. Doras I believe almost immediately switched to higher boost. For 1945, you could have +25 IXs, +21 XIVs and 1,98ata 109Ks etc. Of course there were such plane in late 1944, too, but probably just a few odd examples, that may or may have not have been in combat.

Should be interesting as well - accurate power curves for the DB 605G (later re-named 605AM). Not only it shows the effects of increased boost, it also shows that when the boost is increased AND methanol-water 50:50 (MW50) boost is injected, performance increase also at above rated altitude, without any increase in manifold pressure, probably because of charge cooling. The effect is also noticable on Bf 109K performance curves, where at high alttidue above the "MW abschaltun (MW switch-off)" point the performance drops a bit. MW injection was manually engaged, so even above full throttle height some modest performance boost can be gained by leaving MW 50 injection enabled.

The original aircraft wasn't meant for prolonged inverted flight, either. I doubt any fighter was in the era, what would be the use..? Fuel starvation is probably a good thing in this context anyway, since the lubrication system should be also able to cope with inverted flight, and I am not sure if it was or wasn't. Probably not, though I suppose with a fully filled tank fuel starvation is less of a problem then with a half filled one.. The original 109 manual says that all aerobatic manouvers are permitted, but inverted flight is only allowed for short periods.

How on earth is valve overlap and supercharger control is related?? The actual boost in the engine is regulated by the performance valve anyway... and besides the fact that the DB 6xx supercharger control principle waaay predates the extended valve overlap (which appeared on the 601E).The generous valve overlap, if anything, is a benefit of the precise timing possible with direct fuel injection vs the more orthodox method. Personally, I believe the fixed first speed on the DB series is simply because its much simpler and foolproof to do that this way, rather to overcomplicate things with a double barometric clutch control, for the benefit(?) of a mighty 50-70 PS extra at a rather useless low altitude range... especially with later, MW boosted engines, where the (barometrically controlled) second speed kicked in at ca 600 m altitude already. That being said, the fixed ratio might has to something with the early 601 series lower rpm and special take off ratings - presumably for bombers.

Yes it is not possible to separately adjust MAP and RPM w/o disabling automatic control first.. I probably misunderstood your post, however I think the only practical application would be special (reduced) settings for max endurance and perhaps, range. However if you reduce rpm, supercharger capacity will suffer as well.

No, no, no.... read the pages I posted. For high altitudes, there is an override switch for the (1st) Reglerklappe, which opens it fully. In addition, the s/c always delivers ca. 0,05 ata extra pressure. The "could" part is only possible if the unified throttle setup was somehow incorrectly linking boosts and rpm at lower settings, but i strongly doubt those engineers would be that amateurish.. You can maybe decrease rpm a bit at manual for the same boost, so as to use all that "extra" 0,05 ata that is wasted.. and maybe gain.. well about 20 PS perhaps, and say 10 liter saving in fuel.

You do not get better MP on the 109 by switching back to AUTO due to the how the system works (already described). It just might be possible to squeeze out an extra shaft hp or two from the engine by reducing rpm slightly with manual rpm control, but the whole thing just doesn't make sense on a combat aircraft. Or any aircraft for that matter, as the aim would be unrealistic - to nullify common losses in the system itself. For special, very low power range/endurance maximizing cruise conditions, fiddling with manual rpm could be advantageous and was prescribed (ie. manually set given rpm for given ata pressure). However these are special, static state cruising conditions where it isn't really a problem. Otherwise "full" power is obtained by fully slamming the throttle forward, manual or automatic...

Its automatic all the way (with manual pitch override as an option), these details are about how actually the system works.

I don't have an arguement against it at all. I have said already. "Otherwise its very interesting and IMHO it would be very interesting to see such a sight in a Spitfire, to boost its fighting potential. Its operation seems to be very similar the German Einheitszielvorrichtung EZ 42 sight that is already modeled." It just NZTyphoon/Friedrich/etc. who has issues with modelling German equipment all the time. He simply wants the best of everything, even rare items for the RAF, and the worst of everything for the LW fliers. You see he has issues with the EZ 42 being modelled, he repeatadly said that., making up all sort of nonsense about its use an operation which has been throughly debunked; I on the other hand do not have any issues on seeing the GGS being modelled, quite the contrary, I think it would be great and fun to try it. AFAIK Il2-46 even had a Spit model with it. However I have issues with blanket, nonsensical statements about historical facts. Frankly I couldn't care about the EZ 42 either, but since DCS seems to model a Papageistaffel D-9, which all had them, I'd love to try it anyway. Because its fun. BTW any confirmation on the Spit model? I cannot recall seeing any yet.

Well in my experience is that discussions with certain contributors the noise / signal ratio of threads is usually very poor. No, the original arguement was that: I would say that this notion was shattered pretty conclusively again, you just have to push to right buttons on certain people and pavlovian conditioning will kick in soon and spare you the trouble of disproving their silly ideas. ;) Sure, there is much noise and nonsense, even personal comments in the meantime, but in the end we have learned that this "high proportion of 2 TAF Spitfires" were actually about 10 (ten) Squadrons, give or take a couple, most whom had very little or no actual contact at all with enemy fighters, and whom would be rightfully described by some as insignificant, penny packet numbers. We also learned that the Spitfire had some sort of cold starting device and that some people take special pride in reading books.

The clockwork mechanism was only there on the 601A series, later ones did not have it. But the special hydrocoupling of the supercharger remained, hence the characteristic power curve of the DB 600 series.

The fundamental problem with the Spit IX is that its some 40 mph slower than any of the others. It can't dictate the terms, basically its like shooting at a Soviet biplane in Il-2 - it might be annoying or time consuming, but unless you behave very silly, sooner or later you will land a crippling hit. Or someone else will. Not to diss the plane, by late 1944 this Mark was obviously becoming tactically obsolete - it was an 1942 plane after all. And the awkward control characteristics are too well known.

I have for the 605AS if that helps.

It would seem the DB supercharger was set up so that it would always deliver a bit more pressure than needed, even above FTH, by about 0.05 ata. So for example on this chart (n.b. that it seems the engine develops a lot less FTH than it should, probably had some fault) at 7000m the supercher develops 1.18 ata pressure (Geblaesedruck curve), which is then throttled down 1.14 ata manifold pressure (Ladedruck curve). While this is not full performance, the FTH decrease is just about 200-250 m from the theoretical maximum, which is probably not practically achievable at all times anyways because of tolerances, external conditions etc. But it also means that there always a surplus pressure before the (first) pressure regulator (which is always letting through at least Kampfleistung pressure, i.e. presumably up to 1,45ata on the 605D), so I have doubts if the performance throttle would really not let through the full pressure at all times, since it always receives more pressure than needed! Note that (at least if I read the description of the Laderdruckregler correct) at high altitudes, the first pressure regulator is completely overridden and is fully open at all times! See Bild III, Reglerstellung in Volldruckhöhe (Regulator setting at full throttle height): It's also interesting and could be related or a hint to how things were working that DB manuals usually note that the actual manifold pressure may exceed nominal manifold pressure for a given rating by 0.03 ata during climbs and this is normal. For achieving cruise or econo conditions, the manuals I have seen suggest manual prop pitch control. Also, increasing the revs above rated altitude to maximum revs was permitted, so I guess in practical conditions the pilot would just advance the throttle a bit, which would drive the supercharger harder and open up the throttle more. See the K-4 performance chart indicating "Drehzahlsteigerung" or rpm increase for the 30 minute rating (which is normally 2600 rpm) at about 8800 meter. The performance matches that of the full rating, so it would seem the full 2800 rpm was permitted at higher altitudes for extended periods.

As I understand from the 601/605 Lehratfeln posted just above, the automatic regulator is NOT controlled by the pilot lever at all, normally it sets itself to whatever the Kampleistung rating is (which is 1,3ata onthe 605A, and would be 1,45ata on the 605DB/DC). And it keeps itself that way, unless the pilot lever is advanced to Notleistung, which works as kind of an override and opens the regulator throttle further to give Notleistung pressure levels. The only really "moving" throttles are the next ones operated directly by the pilot lever, but these just further throttle down the pressure, if needed, from that 1,3/1,42ata (or whatever the max. Kampf/Noteleistung ratings are) that is allowed through by the (first) automatic boost control throttle. I think this is where from the the confusion originates.

It seems to me that the DB throttle system is much simpler than on other engines, as it does not need to do much to limit the air pressure delivered by the supercharger. All it does is maintaining the required manifold pressures and prevent too high pressures. Whereas on simpler supercharger designs like the Merlin the supercharger always develops a fixed maximum pressure (ie. a LOT more than desired) via RPM through a fixed engine-to-supercharger gear ratio, which then needs to be regulated and then throttled to the desired engine setting. The DBs gear ratio is, in contrast, flexible (at least with "second" supercharger speed, the first one is fixed ratio) and limits supercharger pressure (Geblaesedruck) in the supercharger itself to a very slightly higher pressure than required - in other word, before the air would meet the throttle(s). So the DB throttles only need to concern themselves to choke and limit the air pressure to engine, they do not really seem to regulate in the traditional way the air pressure from the supercharger. That is already done by the barometrically controlled hydraulic coupling! The DB 601/605 Lehrtafel notes that there 1+1+2 throttles in the system: 1) Regulator throttle (Reglerklappe), this is directly afterwards the supercharger. It is automatically controlled and is largely independent from the pilots lever position. Its main purpose is to limit the pressures at low altitudes (normally to Kampfleistung, ie. 1,3ata on the 605A (that would be 1,45ata for 605DB/DC) It seems the only special position is when the pilot lever is advanced to Notleistung lever position is reached, it opens to allow for Notleistung pressures). It prevents too large pressures, and its main use is to limit pressure near sea level, since the first supercharger speed of the DB 60x series is a fixed ratio, just like on other engines, and can and will deliver very high pressures at SL, well above allowable boost pressures. Otherwise its always fully open at higher altitudes like Volldruckhöhe. This is how it works in detail: 2) Idle air inlet (Leerlaufbohrung), a fixed size inlet (just a drilled hole, really) that is the only thing letting air to the engine at idle, its air let-through capacity is governed by a screw adjustable by the ground crew. 3) Idle throttle (Leerlaufklappe), a varying small throttle that practically opens fully above idle pilot lever position 4) Main/Performance throttle (Leistungsklappe), that opens gradually abve idle pilot lever position and is fully open at Notleistungs lever position Note that real regulation is not neccesary anymore in the second supercharger speed, since that is done by the barometric hydraulic drive of the DB-supercharger..! These throttles only work to limit the charge pressure, ie. maximumizing the allowed pressure in the engine. To me its seem it would logically follow, that if the air pressure actually coming from the supercharger is less than that (ie. higher altitudes above VDH), then its not a problem since the throttles are already in a position that would let more air to enter into the engine than what actually is supplied... The DB Lehrtafel note three special stages of throttling: I. Idle lever position 2) Idle air inlet (Leerlaufbohrung), this is actually just an opening of fixed diamater giving a minimum air into the engine during idle throttle position. The amount of air can be set with a screw. When at idle, all other throttles (except the first Reglerklappe, whichsee below) are fully closed. II. Interim lever position The small sized Idle throttle opens (it does seem that it practically fully opens anywhere above idle lever position), and the larger main/performance throttle also begins to gradually open. So now the air goes into the engine via the idle air inlet (fixed), idle throttle (practically maximum) and the performance throttle (Leistungsklappe, with the opening increasing as does the lever position). III. Starleistung position All throttles, including the Leistungsklappe are fully open, the air goes into the engine at maximum rate. So I think there is probably no trouble with the manifold pressure position, because there is not just the main throttle opening (which indeed does not open fully in an interim lever position, and would limit boost pressure IF IT WOULD BE THE ONLY THROTTLE CONTROLLING IT - BUT IT IS NOT!), but also the idle throttle plus the idle air inlet that lets in air.... the main/performance throttle is just "extra"...

If you mean the cylindrical shaped tank in the rear fuselage just right behind the cocpit, its the tank for MW 50 boost. It was always present on the 109K-4 (and G-14, G-10, too) - it was used the same 87 octane B-4 or 150 grade C-3 being used - all aircraft could use either. On previous aircraft it held 70 to 85 liters of MW-50 (a 50-50 mixture of methanol anti-freeze and water) to increase power via water injection; on the 109K-4, it was also possible to use this tank as an auxiliary fuel tank, in which c, in which case it held 115 liters of fuel, to extend the range of the aircraft by about 25%. When it was used as a fuel tank, a switch connected to a valve was used, which supplied the tanks contents into the main fuel tank instead of the eye of the supercharger. The reason for more fuel was to maintain the centre of gravity (fuel has about 75% the density of MW50). If you mean, however, the small boxy structure in the back of the cocpit wall, it was only present on MW 50 boosted 109Gs, as the battery has to be moved to make way for the MW tank in the fuselage.

You already mentioned the Canadian 411 Squadron, Jeff.

Hi Jeff, I am glad to see you made progress towards a constructive approach! You see, I would very much like to see all common equipment used to be modeled, and the best way you can help the developers in this matter is finding as much information you can. Speaking of which, this is what I have found on No. 485 combat 'experience': RAF Hornchurch was the destination in February 1944, when 485 Sqn, again equipped with new Spitfire IXs (NOTE - prior to that, the 485 was still using obsolete Mark Vs in early 1944...!), became part of 135 Wing with 122 Sqn and 222 Sqn. Preparations for D-Day were under way and 485 Sqn undertook bombing and air-gunnery practice with a new Mk IIC gyroscopic gunsight. There was little chance to try out the new gunsight in action before D-Day however, as the squadron was engaged in bomber escort and saw few enemy aircraft. Opportunities for air to air combat came on D-Day and on the week following, when 485 Sqn. claimed a total of nine enemy aircraft with no losses; these were to be the last enemy aircraft shot down in combat. So, aside the earlier Mark Niner Squadron mentioned, which had some of its planes equipped with GGS and most of late 1944 on uneventful patrols over the Dutch coastline, we have now another Squadron which used the GGS for firing practice in the spring of 1944 and possibly shot down a couple of enemy planes in June 1944, and had no air-to-air success at all afterwards. Still, its better than nothing, at last we now have a single GGS MK IX Squadron that used the GGS in anger. I am sure you can still find us some more, remember, to 2nd TAF on the continent had over 30 Mark IX/XVI Spitfire Squadrons.

I guess there was no need, as they already had first hand experience on the effectiveness and reliability of the MK 108 under high g loads from the Luftwaffe live fire exercises. ;) The British must have been impressed, as they copied the round and the new Mauser revolver cannon firing it as the ADEN cannon, which replaced the venerable Hispano. Here's another shot at it by the British, this time, the fuselage suffers from one 3 cm round.

Volltreffer, Fox One.

I just found this, its a very interesting video, British firing trials with MK 108. ;)

Some Fw 190s with EZ 42, Me 262 with EZ 42 (and I believe its no less than Karl Baur at the stick!) and a very interesting data card on the EZ 42 control box.