Kurfürst

So any chance of evidence of the use of the GGS Mark II apart from a single Spitfire IX aircraft in Nos. 301 and 411 Sqns...? The Uffz. Schallmoser gunsight malfunction is an interesting diversion, but I am afraid the conclusions drawn from it is very outdated and is contrasted by detailed and reliable German sources. Also, from Erich it appears that the EZ 40/42 was first issued in small numbers to Fw 190A-8 and A-8/R2 pilots of 5.Sturm/JG 300 who noticed a remarkable difference in sighting with high % of concentration of hits in a centerized area - killing area compared to using the older sight.

I suppose no information on the number fitted then, so we can't tell if it was typical for late 1944 Spitfire IXs or not. Can you provide an exact reference , preferably a scan for all to see? So, its two Mark Nine Squadrons (310 and 411) out of the ca 30 of the 2nd TAF which may have had two aircraft fitted with gyro sight. Both of which appear to have been primarily used for ground attacks roles, as were most of the near-obsolescent Mark IXs by 1944. Of 411 Squadron, the following is to be noted: "Converting to the Spitfire IX in October 1943 it then became a fighter-bomber squadron. Within two weeks of the D-Day it was operating from France in the close-support role and it also operated armed reconnaissance flights. Following the advancing troops the squadron was soon based in Germany until it was disbanded at Utersen on 21 March 1946". I wonder how many times it even managed to engage 109s and 190s. Did they claim any enemy fighter? There was hardly much "struggle" I would say that is pretty much just the usual wishful thinking. Zeiss's own development wasn't particularly good, so the Askania gyro sight model was chosen and entered into mass production in mid-1944. Te Askania firm was famed for its measurement and recording units, so I guess it had the required experience for designing a superior gyro sight. There was a lack of interest on behalf of the RLM in more complex and expensive sights until 1944, when it entered mass production and was fitted to about 200 fighter aircraft. The development of the EZ 40 gyro sight began in 1935 at the Carl Zeiss and Askania companies, but was of low priority. Not until the beginning of 1942, when a US P-47 Thunderbolt fighter equipped with a gyro-stabilised sight was captured, did the RLM speed up research. In the summer of 1941, the EZ 40, for which both the Carl Zeiss and Askania companies were submitting their developments, was rejected. Tested in a Bf 109 F, Askania's EZ 40 produced 50 to 100% higher hit probability compared to the then standard sight, the REVI C12c. In the summer of 1943 an example of the EZ 41 developed by the Zeiss company was tested, but was refused because of too many faults. In the summer 1942, the Askania company began work on the EZ 42, which gunsight could be adjusted for the target's wingspan (in order to estimate distance to the target). Three examples of the first series of 33 pieces were delivered in July 1944. These were followed by further 770 units, the last being delivered by the beginning of March 1945. Each unit took 130 labour hours to produce. The EZ 42 was made up by two major parts, and lead computation was provided by two gyroscopes. The system, weighing 13.6 kg (30 lb) complete, of which the reflector sight was 3.2 kg, was ordered into mass production at the Steinheil company in Munich. Approximately 200 of the sights were installed into Fw 190 and Me 262 fighters. The pilots reported that attacks from 20 degrees deflection were possible, and that although the maximum range of the EZ 42 was stated as approximately 1,000 meters, several enemy aircraft were shot down from a combat distance of 1,500 meters. The EZ 42 was compared with the Allied G.G.S. captured from in a P-47 Thunderbolt in September 1944 in Germany. Both sights were tested in the same Fw 190, and by the same pilot. The conclusion was critical of the moving graticule of the G.G.S., which could be obscured by the target. Compared to the EZ 42, the Allied sight's prediction angle was found on average to be 20% less accurate, and vary by 1% per degree. Tracking accuracy with the G.G.S. measured as the mean error of the best 50% of pictures was 20% worse than with the EZ 42. I do hope though that the GGS can be modeled, along with the marked inferiority in accuracy compared to the more advanced EZ 42. Provided of course sufficient evidence can be found that it has been used to any significant extent by Spitfire IX units.

Can you specifiy how many would that what you seem believe to be a "high proportion" exactly was? One Squadron, perhaps two flying operational trials, or maybe an odd example here and there? If it was as you claim, I am sure there would be tons of photographic and textual evidence of such a common sight (getit), apart from a picture of a trial aircraft and a picture of post-war Czech Spitfire in Kbely museum. The machine originally belonged to No. 310 Squadron, which : "In 1944, the squadron re-equipped with the Supermarine Spitfire IX and became a fighter-bomber unit with 134 Wing, flying ground attack duties during the Normandy landings. The squadron then spent the rest of the war flying armed reconnaissance missions along the Dutch and Belgian coasts. The final number was 52.5 claims with four V-1s shot down." 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. For those interested in this interesting gimmick, more on the GGS sight from the original Axis History topic from where our dear NZTyphoon has copy pasted the pictures and the transcribed text, kindly provided by Mr. Robert Hurst had originally transcribed the text and pictures. http://forum.axishistory.com/viewtopic.php?f=114&t=17850&sid=bafe3b73e3540eca18d30d7cb698ae39

Further interesting details from Hispano firing trials. The highlights: - API (SAPI) rounds of the Hispano were rather insensitive, they have required considerable structure to function properly (i.e. armored fuel tanks). When hitting 6 s.w.g. plates, 50% of them fucntioned; when hitting less than that, they did not function. - HEIT rounds had a tendency to blow up and damage the gun recoil reducer mechanism of the gun. There has been also production defects with the driving bands, resulting in abnormal ballistics. Either of that happened in one of 15 rounds fired.

The following is a rather interesting article by the well known gun expert Anthony G Williams on the Hispano: The Hispano (technically the Hispano-Suiza HS 404) was designed and developed at the French arm of the European Hispano-Suiza company in the mid 1930s. A firing demonstration of a prototype to British officers in Paris in 1936 banished all thought of the Oerlikon; the Hispano was similar in size and weight, slightly more powerful and fired nearly twice as fast. Unfortunately, the processes of obtaining approval to buy the gun, setting up a subsidiary Hispano factory at Grantham (the British Manufacturing And Research Company, or BMARCO), redrawing the gun to imperial rather than metric units, testing and debugging the prototypes, then fitting them into aircraft and debugging the installations, all took too long for the cannon to achieve anything in the Battle of Britain. A key problem was that the Hispano was designed for engine mounting, which meant that it would be bolted to a rigid crankcase. An aircraft wing is nowhere near as rigid, and this caused problems with all wing mountings, which had to be fine-tuned to achieve reliable gun functioning. In the initial Spitfire installation, which did see brief use in the Battle, matters were made worse by mounting the guns on their side in order to bury as much as possible of the bulky drum magazine within the wing thickness. The Hispano took a marked dislike to its unfamiliar environment and jammed as often as it fired. Much modification was needed to both the gun and the mountings before acceptable reliability was achieved. Even so, the stoppage rate by 1944 was still three times that of the US .50 Browning. A major improvement was the replacement in 1941 of the original 60-round drum by a belt feed. Work was also needed to the ammunition, as it was found that the fuze of the standard explosive shells was too sensitive, causing them to burst on the aircraft skin rather than within the structure where they would do most damage, and plain steel practice shells often proved more effective. By 1941 both a delayed-action fuze and an explosive with added incendiary filling had been developed, but the practice rounds remained in use alongside the HEIs until they were replaced by a new semi-armour piercing round (SAPI) which was essentially an HE shell filled with an incendiary compound and capped with a hard steel tip instead of a fuze. From 1942 on, the standard Hispano loading became 50% HEI, 50% SAPI. Compared with other Second World War 20 mm aircraft cannon, the Hispano was a powerful and effective gun, but only averagely fast-firing and unusually long and heavy. Its weaknesses were addressed in the late-war Mk V, shortened, lightened and speeded-up from 600 to 750 rpm. Here you can compare the size of the .303 Browning with the .50 Browning, the short-barrelled Mk V Hispano and the standard Mk II. The Hispano Mk V could lay claim to being the best aircraft gun of the war, but this mainly saw action in the Hawker Tempest. What became the standard RAF armament of four Hispanos was also probably the best all-round fighter armament of the war, weighing more or less the same as the standard American armament of six .50" Brownings but being about twice as destructive. Tony also noted that in actual practice, the gun was only load only 90 rounds instead of the nominal 120. This was quite common practice btw by armorers to reduce jamming probability. Some practical firing trials were also made in 1942 to acquire information of the rate of stoppages when firing the cannon. Tony reports on that as the following: http://www.quarry.nildram.co.uk/US404.htm In 'Guns of the Royal Air Force 1939-1945' by G.F. Wallace - who was there - there is an account of British tests of the British and US Hispanos which took place early in 1942. The British were unhappy with initial supplies of the American-made guns: "there were frequent misfeeds and lightly struck cap stoppages, and the life of several small components was very short" so a comparative test between one British and three American guns was set up. The intention was to fire 5,000 rounds from each gun without replacing any components. "The British gun fired the full programme but the performance of the American guns was so bad that in each case the trial had to be abandoned before the 5,000 rounds had been fired." The British gun experienced 19 stoppages in firing 5,012 rounds. The American guns experienced 67 stoppages out of 4,092, 97 out of 3,705 and 94 out of 2,610 respectively. Incidentally, Wallace states that the US guns were "beautifully made and better finished than our own" and expressed surprise that although lightly struck caps were a major source of stoppages, even more frequent were mis-feeds. As well as lifespan - apparantly a breach lock crack could be expected anywhere between 1500-2000 rounds. At the suggestion of Capt. E. R. S. Adams of the British Air Mission, two guns each from International Harvester, Oldsmobile, and Bendix were shipped to England for the purpose of competitive aerial tests with the Mark II. Representatives of the Army Ordnance Department were present to observe the 2,000-round tests which were held during July and August 1943. Two British Mark II's were mounted in the left wing of a Hurricane fighter with two AN-M2's made by Oldsmobile and International Harvester in the right wing. Combat flying, dives, G-loading, straight-away, etc., were simulated. One stoppage was attributed to the Oldsmobile gun. The International Harvester weapon had no stoppages but a cracked breech-block was noticed at the completion of the trial. Each Mark II had one sear failure and one of them had a cracked breech lock after 1,400 rounds. The Bendix guns were fired on the ground in competition with the British-made guns and made a creditable showing. In reporting the findings of the test, Mr. Hansen, of the British Ministry of Aircraft Production, declared: "American guns are as good as British guns and are acceptable for service use". There is an inconsistency here. As will be seen below, the performance of the American Hispanos remained unsatisfactory throughout the war, yet the British expressed no concerns and were obviously happy with their guns. There would seem to be only two possible explanations; either the British tolerance of unreliability was considerably greater than the American, or the American guns had been assembled from selected components and thereby performed better than average.

Indeed, I guess there is just not enough space for complex piping in space restrained wing installations. I wonder if there is some detailed manual for the Spitfire describing the sub systems, like board weapons (the pilot manuals we all know are very basic in this regard), as in the case of German aircraft manuals, which have many parts dedicated to each subsystem like fuel system, guns, bombs etc...?

Thanks. So if I understand right, the Hispano cannon had no possibility to reload/recycle in the air in case of say, a jam or a forgetful ground crew...?

A technical question - were the Spitfire's guns breach-loaded and cocked on the ground by hand, or there was a on board system to load the guns? What was the method of actually firing the guns? Pneumatic?

Good point - I suppose armored glass is of the fairly rigid type, and consist of many thin layers sandwhiched-glued together. That combo may crack, especially in the winter.

Another cool little detail / gimmnick: the front armor glass of the 109K could be electrically heating, to avoid misting/fogging, a la on the Me 262. The system only operated when the undercarriage was UP, probably to avoid accidental drain of the battery on the ground.

This might be interesting - two pages from the manual for the 109G-6/U4 (MK 108 version). The part for board weapons in 109Ks manual is missing, but the system was probably the very same (other parts of the 109K manual note the presence of the system, just not the details of its operation). On the Bf 109, upon switching the master arm safety ON at the SZKK 3 board, the system loaded (Durchladung) and the weapon and in case of weapon failure, it reloaded it automatically and cleared jamming after releasing all triggers. The weapons system was operated electro-pneumatically, with electric circuits doing the firing when the trigger was pressed, using 40 V voltage to ignite the cartridge electrically (MG 131, MK 108) - this also facilitated syncronizing greatly for the cowl machine guns and eliminated synchronization losses and reduction in rate of fire. The pneumatic systems using highly pressurized air for cocking and loading the guns, or in case of jam. On the MK 108, air pressure also was responsible for releasing the bolt when firing. Pressurized air bottles were carried on board for this purpose. As noted, this is an early manual from 1943, noting that some electical safeties are missing, so the MK 108 has to be reloaded/unjammed manually, using the P 301 button on the stick. After that, a 2 second delay was to be observed before firing again, to avoid damage to the weapon. When the required circuits were installed, reloading/unjamming was automatic, upon releasing both triggers.

Hi Jeff and thank you for clarifying how you managed to arrive at the production numbers you reported for 109Ks in March 1945. Perhaps you also have some failure rate figures for these "chronic jamming" issues with the MK 108 that would help the developers? I am sure this would be very useful for the development team, or failure rates for Mauser, Hispano and Browning wing installations, if you happen to have any. I do not think however, that the MK 103 was used in the 109K-4, though a slimmer version, the MK 103mot, was developed for use with the K-10. I am sure it would be a lot of fun, though. :) I do wonder though as to what depth weapon systems are being modelled - are automatic re-loading mechanisms (Durchladung) modelled, where present, for example? I cannot remember seeing the Durchladeknopf in the 109Ks 3d cocpit model.

I am still trying to figure out what "built Cham 3/45 = 71 = 133 K-4s" means. It appears to be Mr. Webb's own conclusion on the number built, not Schmoll's and it is of course at odds with the numbers reported by C-Amt/Gen .Qu.(6 Abt.III C) Flugzeugverteilung at the time (168) for March 1945. The other figures reported by Schmoll agree with the numbers put forwards by ArtieBoB perfectly. It may be a case though that the difference is caused by not accounting for the Erla production (obviously, as the numbers presented are for Regensburg only). Well at least we can surely put now "Wolowski's 1200" to rest, though I do wonder where that came from - probably a transcription error from Prien/Rodeike, which sometimes happen with tertiary sources synthetizing secondary sources, but not having access to the primary sources themselves, as in case of Janda/Poruba, Prien/Rodeike etc.

Because subsequent research found the exact number accepted by BAL (LWs quality control /acceptence group), do no need for assumption. Priens work preceeded that reasearch and was probably not available, but the various numbers given by authors up to November/December 1944 match up with these. Even Jochen Prien himself participated in that thread. See this thread, it has all the numbers. http://forum.12oclockhigh.net/showthread.php?t=2462&page=2 "There are two sources for this data, C-AMT Monatsmeldung and the Gen .Qu.(6 Abt.III C) Flugzeugverteilung for various months from Jan 44 to Mar 45. The data as far as I can tell represents neubau Flugzeug accepted by the Luftwaffe (which would mean after flight test acceptance by BAL). " This gives the following numbers for Mtt Regensburg: [TABLE]Date Fact Sep Oct Nov Dec Jan Feb Mar Total K 4 Mttr 15 293 221 325 338 233 168 1593[/TABLE] Note that Milosh's 1945 numbers appearantly have a typo for the 1945 months (the "+" sign). So 1593 K-4s were accepted until the end of March 1945, probably a finite or close to finite number as most factories were overrun in April 1945, inc. Erla. There may be a slight variation between built/accepted numbers, as BAL did not necessarily accept all produced planes if it did not live up to specs within tolerance, though in practice they usually did in the end, if corrections were made to the product. JaPo also has a fate-list for many 109K, this goes as far as WNr. 335 215, so pretty much the very end of the known/allocated 1910 K-4 Werknummers for Regensburg (sans Erla, which may have built a couple in April). So I diss Wolowski because he is clearly wrong - the book seems to be based entirely on secondary sources (ie. synthetizing the already published JaPo and Prien books), and no or very little primary research was done. Such approach is always prone to errors. Out of curiosity it is perhaps worth to mention that the original K-2 (MG 151 armament) was skipped, and apparently they have decided to produce the hybrid G-10 instead, as the G-10s were allocated the serial numbers originally meant for the K-2s. @Lord Pyro, Neubau means "new production" or literally, "new build". It meant planes that were built from scratch ie. were totally new and not conversions/rebuilds ("Umbau") of older planes to new standards, for example an old G-6 rebuilt as a G-14. As seen in the attachment, production essentially switched to high altitude 109s in the automn of 1944 (G10, K-4, /AS types). Note that data for early /AS conversions from early 1944 are missing, since most of those were Umbau.

I would seriously doubt that being an "excellent source" given that they have a wrong number (1200) onthe total production K-4 - the real number was in the order of 1600-1700. Janda and Poruba's books are far more reccommendable on G-10 and K-4 IMO, its fresh, extensive and original research. Prien - Rodeike's 109F-K also, and on the plus side, it also covers all mid-late war 109s in good detail.

AFAIK it worked the same as Allied gyro sights, the aiming circle was set to match the wingspan of the target aircraft (in meters, a short reference table was provided with things like "Boing", "Spitfire" etc.). By placing the target into the sight, and setting it to match, the range was known and a firing solution could be calculated by the sight.

Is that an EZ 42 computing gunsight? :)

There is (was?) however an airworthy G-10 which is pretty much the same thing as the K (disclaimer: yeah "its actually a Buchon" - whatever) plus a lots experience flying a G-2, which is not that far.

Good catch, tapi! :)

Recalling from memory: there was no separate mechanism to give greater boost depending on MW is on or off. the throttle lever was simply set-up to provide greater manifold pressure at max. setting, so pilot was not to push throttle above "Kampfleistung" position if MW was not engaged prior. When throttle was re-setup for MW boost levels (it was advised to allow some 5-10 hours of run-in for new engines before MW use, but this was not strict and allowance was made for emergency needs), former "Startleistung" could not be achieved. But I will have to check it. But as I understand, the throttle was simply moved forward and it gave more boost. There was some kind of blocking, presumably a wire to warn pilot of exceeding Kampfeistung (1,35/1,45ata). If MW was engaged prior - good. If not engaged prior, all sorts of nasty sounds were soon to be coming from engine. When this starts is another question. It seems B4 fuel was good up to at least 1,5ata, C3 fuel - up to 1,8 ata without knocking - these ratings were given by engine manual of DB/DC engine for "dry" (no MW) Startleistung. But I need to check papers to be sure. This is from memory.

Actually DB 605 beat me to it at the very beginning of thread.. so this switch needs to be modelled and added to 3d/system model. IIRC the actual MW 50 "ON" flip switch was located just under the undercarriage indicator, on the lower left part of the dashboard. A manometer was provided to the right of the Revi to check MW 50 pressure - no pressure would mean that MW liquid had run out or, more likely, some malfunction in the system. Given that on high boost operations without MW the engine would be knocking or otherwise endangered, this would signify the pilot to cut back on throttle to safe boost levels.

Its a switch between "MW Stoff" delivery and "Fuel delivery" The 109K, unlike earlier MW boosted variants had a dual purpose rear tank - either for ca. 85 liters MW 50 or for 115 liters of fuel - the purpose of the switch was to supply the rear tank either into the eye of the supercharger (MW injection) or feed it into the main 400 liter fuel tank (when fuel was carried). Obviously it was not good for the engine if that switch was accidentally set to the wrong position. ;)

Complete Jumo 213A Handbuch of May 1944, via the Polish Archives: http://www.muzeumlotnictwa.pl/index.php/digitalizacja/katalog/1197 Junkers Triebweksanlage 9-8013 B-2 1943 (Jumo 213 "power-egg") manual (in development) from September 1943. http://www.muzeumlotnictwa.pl/index.php/digitalizacja/katalog/872

The Erla cocpits on late 109s in Il-2 Sturmovik was probably made by using the 3d model of classsic "boxy" canopy. Unfortunately the upper left/right and front struts of the old canopy were forgoten to be deleted from the Erla 3d model, so you had the Erla canopy struts AND the old canopy struts in the model... You can see it here:

WOW they fixed the Erla canopy graphic bug of ole' Il-2. It only took 15 years LOL. :p