Friedrich-4B

Using the elevator trim to land would also be tricky because, according to the Spitfire IX's Pilot's Notes: there is nothing in the PNs to suggest that the tabs were ever used during landing.

Just a note that N3297 was initially the Mk III prototype, later converted to the first Mk IX prototype.

The difficulty with relying on the NACA report on a Spitfire VA is, as mentioned elsewhere, the elevators had been redesigned for all but the earliest IXs. BTW (and slightly OT) Yo-Yo has described how the FM will handle in this thread: none of the longitudinal instability that some self-proclaimed "experts" have insisted the Spitfire IX supposedly exhibited. :thumbup:

Others have commented that L.F. Mk IXs didn't use the early elevators somewhere way back in this thread (along with the HF aerial wire, that was rarely, if ever, used by operational Spitfires post B of B), so they shouldn't be a feature of the final model.(please, don't use them on the model. Please, please, pu-u-lease?)

Has rel4y got any real data, such as genuine documentation showing the quantities of 100/150 grade fuel consumed by 8th AF & 2 TAF, to back up his claim that Mike and/or Neil fudged the figures? Just wondering... Attached: first is an advertisement on the Vokes filters, as used by the L.F Mk. IX from "Flight" magazine, 1944. Second is an article from Flight, 1946, describing some flight characteristics of Spitfires from the I to the XIV. "Indicator" was probably a Supermarine test pilot, possibly Jeffrey Quill or Alex Henshaw? 1944 - 1252.PDF A Spitfire Score Flight, 1946.pdf

Yo-Yo explained the work that has gone into modelng the Spitfire IX's performance as accurately as possible. My question is, is the currently available data on the 100/150 grade +25 lb boost Merlin 66 good enough to ensure such a variation can be accurately modeled? While the data provided on Mike Williams and Neil Stirling's site is good, it might not be enough to ensure the accuracy that us consumers tend to demand. (Note, for example, that RAF service tests were carried out on several other Spitfire L.F IXs) The point is, I would rather see that ED get the basics right first, before branching out into different fuels and boost setttings. Right now, it shouldn't really matter that we are getting the "plain vanilla" +18lb Spitfire L.F Mk. IXC: the fact is that this, and VEAO's XIV, should be the best available Spitfire FMs yet, and that in itself is worth the wait.

No, there was no major difference; the Mustang IIIs and IVs mostly used the Packard V-1650-7 (some early IIIs had the -3); the -7s had similar power/altitude ratings to the Merlin 66. (eg :) http://www.wwiiaircraftperformance.org/mustang/rae1501.html There were some significant differences between the Packard and Rolls-Royce built Merlins; most of these are explained in the attached article. (Courtesy of AEHS http://www.enginehistory.org/ ) Packard as Aero-Engine Builder.pdf

[ame]http://www.spitfireperformance.com/JL165-Rolls-Royce.pdf[/ame] JL165 was built as a Spitfire VC in March 1943, but modified to a Mk IX later in the year. http://www.spitfireperformance.com/jl165form78.jpg JL165's s performance was slightly lower than usual for an L.F Mk IX. also see: http://www.spitfireperformance.com/merlin66_18_25.jpg http://www.spitfireperformance.com/merlin-comparison.jpg

Having looked through 485(NZ) Sqn's ORBs, I can't find anything to confirm that 485 carried out their own conversions, without Supermarine's Mod.1029. In addition, the article referred to on the Spitfire Site gives no references. I'll keep digging, when I have some spare time, but, for now this looks like it's a myth. Speaking of myths... What Kurfrust has failed completely to understand, is that Spitfire XIIs and early F. Mk IXs were not ex-Spitfire VIIIs or VCs that had had their engines taken out and replaced with Griffons/Merlin 61s; they were new-build aircraft, and shown as such in serial number lists and more importantly on their Aircraft Movement cards (in the same way as 109G-6s were renamed G-14s).

In other words, lots of fudging around, with no references or sources given, and a whole lot of excuses for not including aircraft that, unarmed or not, were an integral part of two-stage Merlin engined Spitfire production. :thumbup: Of more interest is that the first .50 cal installations were made at Castle Bromwich, not at 125 Wing, and certainly not by 485(NZ) Squadron. eg: MK754 LFIX CBAF M66 .5in guns 33MU 5-3-44 485S 8-6-44 332S CAC ops 11-10-44 ASTH 15-2-45 sold Turkey 30-4-47

I am fully aware of that: what I am saying is that Kurfurst has provided no credible reference for either chart and, more specifically the Spitfire chart. That's part of the problem: the other problem is how, exactly, did Kurfurst determine the production numbers of Spitfires from month to month? To do so he would have had to count every single Spitfire in the IX/XVI VII/VIII family, making absolutely sure that every single serial number has been located in the right order in the production sequence. For example, according to Morgan & Shacklady, and http://www.airhistory.org.uk/spitfire/p071.html , MK661 was delivered to 9 MU on April 5 1944, MK662 was delivered to 39MU on 28 February '44, while MK668 was delivered to 39 MU on 25 February: there are many, many such examples where Spitfires with sequential serials could be delivered to MUs two or three months apart, but did this actually mean that they were built in this order, or did this mean that they were recorded as arriving at an MU on those dates? Because so many Spitfires were possibly delivered well out of sequence, each serial number has to be checked (and, hopefully rechecked) to ensure that they are plotted into the right production months. Has Kurfurst actually bothered to do this, or has he just taken job lots of serial numbers and assumed that all were built in the same month? BTW: M & S used the Aircraft Movement Cards (Air Ministry Form 78 ) as a source. (See [ame]http://www.rafmuseum.org.uk/documents/Research/Research-Enquiries/e-Info-Sheet-5-Aircraft.pdf[/ame] ) as references. Dead right. In summary, Kurfurst's Spitfire production chart looks pretty, but is nothing more than a rough guesstimate of monthly production. To check it properly would mean auditing it against the production lists provided by M & S and the well researched website http://www.airhistory.org.uk/spitfire/home.html Frankly, why bother when there are reliable sources on Spitfire production that can be readily accessed? Besides which, it has nothing to do with ED's Spitfire IX FM.

I take it that Kurfurst has some absolutely reliable statistical information showing that the RAF's abort rate due to mechanical trouble was somewhat worse than the USAAF's? If so, it would be good to see it, rather than relying on Kurfurst's guess work. The short answer to that is that the majority of K-4s were firmly entrenched on the Eastern front, either facing the hoards of Russian aircraft or engaging in ground attack missions; those K-4s that remained on the Western front were mostly facing the USAAF's fighters and bombers - and getting shot down in droves - or engaged in ground attack work, or facing 2 TAF and not really being noticed. And where is the historical evidence to show Spitfire IX pilots sat around sipping tea while the Yanks did all the work. Also, where is the historical evidence proving that the Spitfire IXs only flew when the Yanks spared them some fuel, and did nothing but drop bomblets, blah, blah blah? This is all just rhetorical nonsense, designed to insult the British and Allied pilots of 2 TAF, and denigrate the Spitfire IX, while adding nothing useful to this thread. Charts without credible references and no explanation as to the methods used to construct them; how-er-convenient...:music_whistling:

I doubt if it was as simple as that; at the very least, any squadron carrying out such a conversion would need the conversion kits issued by Supermarine, if not help and advice from Supermarine or Castle Bromwhich field teams. Don't forget that at about the same time, 485(NZ) Sqn's Mk IXs were also being fitted with the gyroscopic gun sights, so life would have already been busy for the ground crews. As it is, 485 Sqn's ORBs from January through May 1944 show no evidence that any such work was carried out by the squadron, so it's far more likely the conversion work was done by 135 Airfield (later Wing), which also incorporated 222 and 349(Belgian) squadrons. (The ORBs do show that 485(NZ) Sqn re-equipped with L.F. Mk IXs between February 13 and 20: the first operations over France with the IXs, escorting Ramrod raids, ran through from March 4 to 20, then recommenced on April 4 through to May 30.)

The E type armament was introduced before D-Day (see attachments - excerpts from Shores & Thomas' 2nd Tactical Air Force Volume Four), and, by the end of July five Wings of 84 Group were equipped with what were initially called "Spitfire IX LF .5"s. from a 2 TAF squadron list posted by re14y 131 Wing 302 (Polish) Squadron Spitfire IX WX 308 (Polish) Squadron Spitfire IX ZF 317 (Polish) Squadron Spitfire IX JH 132 Wing 66 Squadron Spitfire IX LZ 331 (Norwegian) Squadron Spitfire IX FN 332 (Norwegian) Squadron Spitfire IX AH 134 Wing 310 (Czech) Squadron Spitfire IX NN 312 (Czech) Squadron Spitfire IX DU 313 (Czech) Squadron Spitfire IX 135 Wing 222 Squadron Spitfire IX ZD 349 (Belgian) Squadron Spitfire IX GE 485 (NZ) Squadron Spitfire IX OU 145 Wing 329 (French) Squadron Spitfire IX 340 (French) Squadron Spitfire IX GW 341 (French) Squadron Spitfire IX NL plus 125 Wing of 83 Group: 125 Wing 132 Squadron Spitfire IX FF 453 (RAAF) Squadron Spitfire IX FU 602 Squadron Spitfire IX LO While the wing bomb racks may have appeared to be standard on the E, they could always be removed when not required.

The fact is that we are getting the +18 lbs boost L.F Mk. IX, with the hope that in future +25 lbs will become an option. In the meantime, is it really worthwhile worrying about this well before the FM is even released?

This is fudging the real story: In June 1944, there were two Spitfire IX squadrons (1 and 165 Sqns) in ADGB, because 2 TAF took priority. It should be noted that they had converted to the fuel before the V-1s arrived. The claim that "there was no operational introduction in the whole 1944" is disingenuous, because operations were certainly flown, by fully operational (as opposed to trials) squadrons, operating from frontline airfields. And the anti-diver operations were hard yakka on the pilots, and a real test of the aircraft. The rest of the ADGB squadrons equipped with Spitfire XIVs, Tempest Vs and Mustang IIIs were converted to use 100/150 grade fuel when the V-1 threat became real. The reason these units reverted back to 100 Octane and +18 lbs boost was purely logistical: http://www.wwiiaircraftperformance.org/150grade/18-sept-44-doc.html http://www.wwiiaircraftperformance.org/150grade/150-grade-fuel.html

The L.F Mk IX and related Mk XVI were primarily used as fighters and fighter-bombers by 2 TAF with a secondary role of Tactical Photo Reconnaissance; the XIV was used a medium-high altitude fighter and Tac P.R aircraft. The other RAF single-seat, single engine aircraft were the Hawker Typhoon, which was primarily a fighter-bomber, and Hawker Tempest, which was primarily a low-medium altitude fighter. The Mustang III was also used as a fighter and fighter-bomber by 2 TAF, until the Mustang squadrons were transferred to ADGB to be used as long-range bomber escorts Ditto - the IX promises to be one of the best Spitfire FMs available anywhere, so I'm not getting worked up "competitiveness" - I'm just going to enjoy the ride.

http://www.amazon.com/Republics-P-47-Thunderbolt-Seversky-Victory/dp/0962935913 The main proviso I have is that while the book is really comprehensive, and a great source of P-47 info, danged if it isn't one of the worst edited, most irritating to read books in my collection.

I know it's way OT, but here are some documents on using FARPs [Forward Arming Refueling Point(s)] U.S Marines setting up a FARP [ame]http://www.globalsecurity.org/military/library/policy/army/fm/3-04-104/fm3-04-104.pdf[/ame] [ame]http://www.globalsecurity.org/military/library/policy/usmc/mcwp/3-21-1/ch7.pdf[/ame] Back OT: the original Allied airfields in Normandy were FARPs, because (for example) Typhoon units could operate from them during the day, then fly back to British bases overnight - particularly when German artillery was still within range. :pilotfly:

Where on earth did that nonsense come from?? Spitfire IXs routinely carried 250 lb bombs, plus racks, under the wings on operations, with no reports from 2 TAF or any other source complaining of constant undercarriage failures. How, then, could the weight of another Hispano in the wing cripple the aircraft, when ~270 odd pounds + drag under the wing didn't? :huh:

For interest, in March 1944, MJ823 was tested by the A&AEE with 2 x 250 lb bombs on underwing racks, while in June it was tested w/1 x 500 lb bomb under the fuselage and 2 x 250 lb underwing bombs. Is ED's FM likely to carry these loads as options?

The S.U Injection system was, in fact, standardized for several later Merlin models (e.g - Merlin 130 series in De H Hornet). It had nothing in common with the S.U. carburettors used in cars (which (warning OT), BTW, work extremely well when properly maintained - problems such as "inaccurate fuel metering and sluggish throttle response" are the result of inadequate/careless maintenance and are not inherent to the design http://britishclassicmotors.com/3301.html ). It is slightly sad that someone who has long been a deeply devoted Spitfire fan, is so disappointed with how the DCS L.F Mk. IX is likely to perform, especially because he has gone to such lengths to provide Yo-Yo with a comprehensive, in depth analysis proving that the Spitfire should lose at least 3 mph. It would seem that the Type A design was first used in the Spitfire VIII as Mod 751, October 1942; Type B was first tested on MA648 in November 1943 (hence "new" intake design) [from Morgan and Shacklady, pages 289 & 316]. Type C had improved seals, as well as the additional plate, possibly as a result of the test cited by Yo-Yo.

A correction on my part: Morgan and Shacklady, page 282, shows there were three types of Vokes filter systems: Type A, without a louvred plate under the filter element; Type B w/louvred plate (mod. 1068 ) and Type C with an extra plate with square holes on top of the filter element, plus modifications to the seals. There was no change in the filter element itself. What did change was the louvered plate reduced the performance loss from having the filter element open directly into the intake, as shown in Yo-Yo's attachment.

The soils in the region of Normandy where the Allied airfields were constructed, are full of hard silicates that severely reduced the life of an aero-engine when ingested, so it's more likely that the air filter was used in Normandy; eg: in this photo, the intake shutter near the mouth of the intake is down. The bypass was used was during ground running & takeoff or landing, or when flying in a dust or sand laden atmosphere Spitfire VIII Pilot's Notes, also relevant to 1944-45 L.F. Mk. IXs (ignore the details for early aircraft): As it is, unless any future Normandy airfields on DCS maps can reproduce the dusty conditions, whether or not the filter was used is moot.

Rather than providing a chart showing the comparative differences between a (presumed) 109G at take-off weights of 113% & 95%, it would be more useful if Kurfurst could calculate and provide a dataset and performance curves for a Spitfire L.F. Mk. IX's performance at 100% T/O weight, taking in all the information Yo-Yo has tried to explain to him. That way we can all see whether Kurfurst's argument holds any water or, whether, as Yo-Yo has explained, the real world difference was minimal Note also that the A&AEE calculated that the average speed difference due to the different FTH's of the 4 Mk IXs tested was 3 mph (5 km/h) - ie; average human walking speed. ( see:http://www.spitfireperformance.com/ma648.html ) Reviewing Kurfurst's "proven and explained reasons" for considering the flight test results as "dubious": From the first page of this thread: See: http://www.spitfireperformance.com/bs543.html * BS543's Merlin was not operating on a too rich mixture because while the A&AEE report mentions that BS551's Merlin 70 was operating on a too rich mixture, there's no mention of BS543 having similar problems. Kurfurst is merely reading this into the report, based on his coloured interpretation of the performance curves. * BS543's Rotol propeller was a "serialized" propeller that was proven to be slightly less efficient than others tested on other Spitfire IXs - it did not confer a magical performance boost. See: and http://www.spitfireperformance.com/proptypes.jpg. *BS534's level speed and climb rate NOT Full Throttle Height was used as a reference by Yo-Yo. http://www.spitfireperformance.com/ma648.html * The only "experimental" feature of MA648 was the S.U. Injection carburettor that conferred a maximum FTH advantage of For the rest, MA648 had the Vokes Universal carburettor air intake fitted to production standard L.F. Mk. IXs operating over Europe. What Kurfurst fails to mention is that Yo-Yo also used JF275 (FTH 20,200 ft, 405 mph), an L.F. Mk VIII, as a reference.