Points of interest:
ad 1, High speed handling:
ad 2, As for the AS supercharger was not up to the task... really, the single stage AS and D engines outperformed the two-stage Merlins in power output at altitude, ie. the DB 605AS FTH height being 8000m, higher than any of the Merlin 6x series, and putting out apprx. 100 HP more, at much lower consumption etc.
As for the critical altitude of the engine being 'reduced', it`s rather irrevelant IMHO, the altitude power output remained the same, just at higher outputs yielded more power at low altitude; a limiting factor of course, the supercharger to extend the extra boost range. The performance would be the same, a K-4 would make just as well 680 km/h at 1.8ata at 10 000 m, and 680 km/h at 10 000 m with 1.98ata max boost, the only difference being an improvement of speed (~13-15km/h)between SL (594 km/h to 607 km/h) up to 7500m. Even at 2.3ata, the HA performance would be the very same -
still680 km/h at 10 000m, even though the speed would further increase below 6000m, to about 640 km/h or so at SL... so I really don`t think it`s appropriate to speak about lack of s/c performance, since the s/c was well capable of creating VERY high performance at HAs. Lowered FTH is a natural thing to happen with increased boosts.
Same thing happened to Merlins, ie. Merlin 66 was unable to maintain max. boost after
only 500 ft at 150 grade fuel and MS grade etc.
ad 3, Compared to the G-14 being produced only in August 1944, the Allies already captured imtact examples in mid July, ie see the 109lair for info, but Knoke`s diary already talks of Bf 109Gs 'with methanol injection and large compressors', ie. with high altitude 1800PS DB 605ASM as early as April 1944.
ad 4,
"Even the larger Fo987 oil cooler was not installed in all a/c, reducing the power output potential of the engine"Reducing? How? Power output was the same whatever oil cooler was installed.
ad 5,
The AS was only about 1 in 6 of G-14 production and was spread out along the whole production series. Rather interesting math, ie. considering at least 1835 G-14/AS were built, out of appx. 3000-4000 G-14s in total, which means every SECOND G-14 was a G-14/AS.
As a matter of fact, the output of the Regensburg factory was 1373 G-14/AS vs. 479 G-14s up to end of 1944 etc.
That similiar hysteria already caused Milo a permament banning on ubi forums, hopefully such action doesn`t wait for long here either. Ever since at ubi discussions are much more productive w/o provocations etc. that set the talk on sidetrack.
ad 5,
"In the terms of raw performance it was certainly pretty good at low and medium altitudes throughout war, at high altitude the allies had clear advantage from spring 1942 onwards (when the two stage Merlins and American turbo engines reached service). "
Hardly, it was rather more contested. In 1942, the Bf 109G had clearly better performance than the MkIX Spitfire at speed at all altitudes, including HA. It also outclimbed them, though at very HA the Spit had some climb advantage. At least on the paper, reality was something different,that there were rather few MkIXs around and many 109Gs.
It could match the speed of any turbocharged US desing of 1942 or 1943 - P-38s or P-47s, and outclimb them at all altitudes. P-47s increased their speed with the introduction of paddle blade props in 1943, but they were still not much faster, and were hopelessly outclimbed. P-38s never become any faster. Not counting GM-1 carrier Bf 109s of course, which would throughly swap the picture of HA performance again, but leave those special variants alone for the time being.
From
1943 onwards, most Spits produced were low altitude versions, with slightly worser performance at HA than previous MkIXFs, and close match in speed to 109Gs at HA - the picture did not change in their respect until early
1944, when the German began to use their /AS powered Bf 109s, which considerably outperformed any Spit IX`s speed at altitude. In fact, these high altitude 109s (G-6/AS, G-14/As, G-10, K-4) could
cruise faster than the maximum 5min limit speed of Spitfires at those altitude at 8-9000m.
The P-51 was, only comparable in speed, and again, inferior in climb. The general picture again, for 1944, is that the USAAF has types that are as fast as Bf 109s a HA as well, though outperformed by them in acceleration and climb rate, whereas 98% of the RAF`s planes simple can`t hope to catch Bf 109s anywhere above 16000 ft.
It appears the reality behind the claim 'clear Allied HA advantage from `42 onwards' is rather more complicated as some may imagine. So much that it can be as well the exact opposite case, ie. for 1944.
ad 6, As for the claims about small airframe being a limiting factor on the 109s - this was never proven in history. Fact is that they didn`t mount more fuel for the simple reason
they didn`t need to, milage of the DB engines increased through the war, as newer models operated on higher CR, higher FTH with leaner mixtures but allowed for higher cruise speeds, as opposed to developments of R-R, which turned into fuel hogs, and required the increase of fuel capacity in late Spitfires by 50%, whereas range remained the same and endurance was even
less than before; Bf 109F/G/K models continued to have
more range on
less fuel than Spitfires - something not only due to the increasing thirst of Merlins, but also because the fact that the
larger airframe also creates more drag - no1 reason why Messerscmitt choosed a new way, high effiency via advanced solutions instead of relying on old school solutions.
Fuel tankage
had to be increased due to the flaw of the Merlin powerplant, not by free choice. The added weight considerably detoriated handling characteristics and performance on the later Spits (and the same thing happened on P-51s with rear fusalge tank to maximise range - I always wondered how well would the P-51D do with a DB 605D instead of the Merlin 67 ), something that was certainly not desired by Messerscmitt, but thanks to the work of DB, he had other choices.
As the weapons being mounted, Bf 109s could mount up to 3 cannons, 20mm or even 30mm ones, and two heavy MGs - good enough as Allied bomber losses show. I certainly would not call an airframe unable to be armed effectively, which could carry no less than three MK 108s, and could also mount an MK 103, Hispanos etc with ease.
