Operation Sealion - RAF and Luftwaffe Plans & Preparations

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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 08 Dec 2017 11:45

Interesting if grainy picture taken in March 1941 showing how the Luftwaffe, in this case Zerstörerschule 1, made use of captured aircraft. The caption is not quite correct I think, I count three Fokker G1 (Dutch), two Breguets and one Potez. In addition, the school also used Bf 110, He 51 and Fw 58 in this period.
From S. Carlsen and M. Meyer, Die Flugzeugführerausbildung der Deutschen Luftwaffe 1935-1945.
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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 17 Dec 2017 17:32

Christer Bergström in his book about the BoB gives some detailed info about the training of a young Luftwaffe pilot, Alfred Grislawski: did about 80 hours of basic flying training, then was selected for fighter training in April 1940 and flew 34 hours at a Jagdfliegerschule, half on Bf 109 and half on Avia B 534 and Fw 58. Then on to the Ergänzungsjagdgruppe Merseburg, where he flew a further 8 hours on the Bf 109, and in early August he joined III./JG 52 at the front. That would be comparable to the 20-40 hours new Hurricane and Spitfire pilots got to fly on those types in OTUs before joining an operational squadron. I found a reference to a pilot who did only 12 hours on a Spitfire before being posted to a squadron, but fortunately for him that squadron was rotated up North where he then had a few weeks to acquire some more flying experience. Luftwaffe fighter units did not enjoy any such reprieves.

In his recent book about Operation Sealion, We March against England, Robert Forczyk claims (p. 205) that in the RAF most replacements had 15 hours or less in a Hurricane or Spitfire while “new Bf 109 pilots typically had at least 250 hours of flying experience”. That is clearly a case of comparing apples and oranges, namely hours on operational fighter types against total flying hours, and even so 250 hours is probably on the high side for new Luftwaffe fighter pilots arriving at the Channel front in Aug./Sept. 1940.
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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 06 Jan 2018 10:16

A note on aircraft armament:

The Bf 109 fighters used in the BoB were almost exclusively of the "E" version; surviving older B, C and D versions had been relegated to training and while a handful of the "F" version appeared in October, there were some production problems and no more than fifty were delivered before the end of 1940.

A point not often mentioned in accounts of the BoB is that a considerable portion of fighter strength consisted of E-1s which had only four MG 17 machine guns. The E-3 and E-4 were armed with a 20 mm gun in each wing and two 7.92 mm machine guns in front of the pilot. The E-4 carried the modified MG-FF/M guns with could fire Minengeschosse with a larger HE payload.

Bergström, p. 57: of 740 serviceable Bf 109s on 31 Aug. 1940, 307 were E-1s, 103 were E-3s, 304 E-4s and 27 E-7s. Production of the E-1 was terminated in August (1183 built in all, including 110 E-1/B with bomb racks for a 250 kg bomb), but of the 323 Bf 109s delivered in September 100 were still E-1s.

It appears that E-3s (production of which had been terminated in June) were gradually upgraded to E-4 standard by fitting the MG-FF/M guns (and possibly other changes such as additional armour plates). Of the 476 E-4s built up to October, the last 226 were E-4/B fitted with bomb racks. Production of the E-7 started in August; again some aircraft of older versions were gradually upgraded to this model and then so designated. The E-7 had a new engine (DB 601/N) and fittings for a 300 l. droptank. Apart from these upgrades, it appears that repaired aircraft were sometimes "hybrids", an E-1 with E-3 wings for example.

The MG-FF was a relatively low-powered 20 mm gun with a muzzle velocity of 600 m/sec (700 for the MG-FF/M; the 20 mm Hispano-Suiza gun coming into service with the RAF had a MV of 850-880 m/sec and delivered about twice the muzzle energy). It was therefore more suited for firing at bombers than at nimble fighters. Ammunition carried was 60 rounds per gun (in drums) which provided about seven seconds of firing (in short bursts obviously). After that, the pilot had to rely on the two 7.92 mm machine guns in the nose, which with 1,000 rounds apiece could keep going for a minute. Spits and Hurricanes carried eight machine guns with 300 rounds each, enough for about sixteen seconds of firing.
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jeffreyd357
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby jeffreyd357 » 16 Jan 2018 09:06

Knouterer wrote:Note on the armour-piercing bombs of the Luftwaffe:

In case of invasion, the RN did not intend to risk its capital ships in the Channel or near it unless the Germans did too (the Admiralty being unaware that in Sept. 1940 all the remaining larger units of the Kriegsmarine were under repair or not yet operational, except for one heavy and three light cruisers).

If however the situation had become desperate, the closest battleships/battlecruisers would have been Nelson, Rodney and Hood at Rosyth. As later events would show, the armour protection of Hood was not thick enough to save her, but Nelson and Rodney carried very heavy armour belts and decks (see diagram, from Norman Friedman, The British Battleship 1906-1946). Note that the main armoured deck, as was also the case for other battleships, is not the weather deck but two stories down.

Earlier in 1940 a few Luftwaffe experts sat down to calculate what kind of damage various types of German bombs might do to various types of British warships, taking the battleships Nelson and Queen Elizabeth (older and less well protected than Nelson and Rodney) and the cruiser Dorsetshire as representative examples. According to these calculations, “it would not be possible to sink the heavily armour-plated battleship Nelson with a single hit by a PC-1400 bomb, which could only cause damage to a greater or lesser extent by full or near hits” (http://www.afhra.af.mil/shared/media/do ... 04-090.pdf , p. 317).

Development of armour-piercing bombs for use against fortresses and heavier warships with armoured decks had started in 1938. These weapons were designated PC for Panzersprengbombe Cylindrisch.

The PC-1000 (1000 kg, of which 150 kg explosive charge) could penetrate 110 mm of armour (or 117 mm according to some sources). However, this maximum performance was only achieved if the bomb was dropped from an altitude of 4,000 m or more to achieve maximum velocity. From typical dive-bombing altitudes penetration was reduced by about 50% and there was a good chance that the bomb would bounce off. The Germans tried to solve this problem by developing rocket-assisted PC bombs, but these were not yet available in 1940. There was also a heavier PC-1400 as mentioned above, but it was not available in any numbers, anyway the Ju 87 (B and R versions) could not have lifted it, although the Ju 88 could.

On 10 Jan. 1941 Stukas of I./Stg 1 and II./Stg 2 attacked the carrier Illustrious in the Mediterranean and scored half a dozen hits, including some with PC-1000s, which in at least one case did penetrate the armoured flight deck, but only just apparently. As this was about three inches thick, and the main armoured decks of Rodney and Nelson were much thicker, the chances of sinking them by such attacks would indeed have been minimal, it seems. Of course, even if they did not sink their targets outright, such heavy bombs could still do a lot of damage and perhaps force the ship to turn back.


I'm sorry my friend I would just like to point out your PDF link is broken for that second spec you mentioned. Thanks for the post though! Very interesting indeed.

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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby jeffreyd357 » 16 Jan 2018 09:20

[quote="Knouterer"]In that context, about the Luftwaffe's torpedo planes: the only operational torpedo plane at this time was the He 115 floatplane, which was too slow and vulnerable to attack warships or strongly defended convoys. Some testing had been done with He 111s, but none became operational as torpedo bombers before 1941. Ju 88 torpedo bombers entered service in 1942. The obsolescent He 59 floatplanes had by Sept. 1940 been relegated to rescue, reconnaissance and transport tasks.

By September, the first Staffel of Küstenfliegergruppe 506, based at Stavanger, had five aircraft recently fitted for torpedoes while the other four carried bombs (2 x 250 kg typically). 2./506 and 3./506 also had (some) He 115 fitted for torpedoes. Stocks of aerial torpedoes were however minimal, 38 in total by Sept. according to Thiele. As with other German torpedoes, the LT-F5 (a Norwegian design built under licence) often malfunctioned.

1./ Kü Fl Gr 106 with He 115, operating from Brest (previously Norderney), was mainly engaged in dropping magnetic mines in this period, but also reported launching 16 torpedoes between the start of the war and 1 Oct. 1940 and claimed 2 hits. (2./106 equipped with Do 18 flying boats was also at Brest, 3./106 with He 115 at Schellingwoude)

As of 28 Oct. 1940, the Luftwaffe had 68 LT-F5 torpedoes “cleared for action”. More were in the pipeline, and it was hoped to recover a number of sunken torps. 300 italian torps had been ordered, and there were 400+ captured “small bore” (40-45cm) French, Dutch and Norwegian torps, some of which might be adapted for use by the Luftwaffe as aerial torps.

Successful aerial torpedo attacks by the Luftwaffe were rare in the first years of the war. On 18 december 1939, a British fishing vessel (Active, 185 GRT) was sunk by a torpedo (launched by a He 59). On 26 Aug. 1940, the freighter Remuera (11,445 GRT) was torpedoed by a He 115 (Kü Fl Gr 506) off Kinnaird Head. On 15 September, the steamer Nailsea River (5,550 GRT) was torpedoed by a He 115 in the North Sea. In one or two other cases, it is not entirely clear whether ships were sunk by bombs or by torpedoes.

I think you possibly might be in error on your data on early war operationally used aerial torpedoes. I can't seem to recall exactly where i read this but it might have been NavWeps online. Long story short I believe it said the luftwaffe and such mainly used aerial torpedoes designed in Italy and their designation was indeed LT5 I believe with of course variants progressively going past that. Makes you smile that Italians made a good enough weapon that the Germans used instead of local procurement and design. I jest I'm half Italian so I make no slight to my familys motherland. Always here that in Ww2 Italian weapons tech etc Was sorely outdated but they had a few things on parity with the allies. Again sorry for not posting exactly where my data was found. I realize it is totally lazy and unprofessional but i did remember the Italian aerial torp and wanted to share. Also again great post and thanks!

Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 17 Jan 2018 12:48

The document referred to above can now be found here: http://www.ibiblio.org/hyperwar/AAF/AAFHS/AAFHS-192.pdf Title: The Planning and Development of Bombs for the German Air Force, 1925-1945.
The discussion about bomb effectiveness against various types of RN ships is on page 305-312.

Re: German aerial torpedoes, my understanding is that the original LT-F5 was based on a Norwegian design as I wrote; the improved F5b entered service in late 1941, and in the interim the Germans ordered a number of Italian 45 cm Fiume torpedoes (as I also mentioned), which they designated the F5w.
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby jeffreyd357 » 20 Jan 2018 13:43

Maybe indeed your correct and I misunderstood the detail. Even though it looked as they all were in that F5 designation regardless where design originated or procurement. Thanks again Knouterer as always your attention to detail keeps me reading with your precision :-)

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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby jeffreyd357 » 20 Jan 2018 13:47

Of the top of your head do you know any knowledge of where possibly on this site I may find more info on the progression of European torps? Say starting from whiteheads and Fiume designs on?

Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 21 Jan 2018 08:50

jeffreyd357 wrote:Of the top of your head do you know any knowledge of where possibly on this site I may find more info on the progression of European torps? Say starting from whiteheads and Fiume designs on?


Try the search function, there are several threads about torpedoes.
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 26 Jan 2018 11:44

Knouterer wrote:A note on aircraft armament:

The MG-FF was a relatively low-powered 20 mm gun with a muzzle velocity of 600 m/sec (700 for the MG-FF/M; the 20 mm Hispano-Suiza gun coming into service with the RAF had a MV of 850-880 m/sec and delivered about twice the muzzle energy).


The 20 mm Hispano gun did not play much of a role in the BoB. A handful were installed on a few Hurricanes and Spitfires but there were reliability problems, in addition the underwing installations created drag. Only a few enthusiasts liked them, as in the story below (from Andy Saunders, Battle of Britain - RAF Operations Manual).

The twin-engined RAF fighters armed with 20 mm guns were only just coming into service. In his OOB of the RAF as of 30 Sept. 1940 Philson lists a dozen operational Beaufighters with various night fighter squadrons (mostly equipped with Blenheims) and seven Whirlwinds (five operational) with 263 Squadron (see previous page).
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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 31 Jan 2018 22:44

Interesting TO&E of a Kampfgeschwader, taken from Chronik KG 51 "Edelweiss" by Wolfgang Dierich. No date but a bit later than the period under discussion, in the BoB period KG 51 was equipped with the A-1 version of the Ju 88 (97 in all as of 13 August, of which 71 serviceable). These were exchanged for the A-4 in March 1941, just before the Balkan campaign.

This TO&E is a bit confusing in that it suggests that there were 12 Staffel in a Gruppe, but of course there were only three. As with the Jagdgeschwader (see above) the fourth (IV.) Gruppe was added to the Kampfgeschwader in late 1940/early 1941, to give new crews final training before they were assigned to one of the three operational Gruppen.

It shows that while the Staffel (131 strong) included some support staff, most of the technical and administrative support was provided at Gruppe level, and in fact the Gruppe generally went into action together in the BoB period; sometimes missions were carried out by a single Staffel, but that was rather the exception, AFAIK.
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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 02 Feb 2018 13:10

Knouterer wrote:A point not often mentioned in accounts of the BoB is that a considerable portion of fighter strength consisted of E-1s which had only four MG 17 machine guns. .


As noted already, many E-1s were later (retro)fitted with 20 mm guns, but the MG-armed version was also still in frontline service as late as the end of October, as appears from this report:

http://www.aircrewremembrancesociety.co ... index.html

Production of the E-1 and E-3/E-4 ran more or less concurrently, and according to one source I found the idea was that the leader of a Rotte would fly the cannon-armed fighter to deliver the killing blows, while his wingman, covering him, would fly a MG-armed E-1.
Last edited by Knouterer on 03 Feb 2018 08:56, edited 1 time in total.
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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 02 Feb 2018 19:40

Knouterer wrote:On the subject of repaired aircraft: the Statistical Digest states that 660 aircraft were repaired in the 3rd quarter of 1940 (738 in the 4th). Makes 220 per month; Fighter Command sustained most combat losses in this period but throughout the RAF there were many losses through accidents too of course, Training Command in particular suffered a lot of crashes as one might expect. From breakdowns later in the war (late 1941/1942) it appears that the number of repaired trainers was roughly equal to the number of repaired fighters. We can tentatively assume that the number of repaired fighters returning to service in September was around a hundred. Perhaps a bit less.


Christer Bergström in his recent book about the BoB claims (p. 281) to have made a detailed study of British records and concludes that the following numbers of RAF fighters were shot down but could be repaired:

July - 27
August - 86
September - 134
October - 42

Most authors seem to agree that RAF combat losses in August and September were about 750 fighters in all. So that would mean that 29% of those losses were only temporary, so to speak.
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 26 Feb 2018 10:18

Brief note on aerial reconnaisance by the Luftwaffe in this period, an aspect that can cause some confusion as aircraft used for reconnaissance such as the Ju 88 are sometimes counted as part of the bomber strength and sometimes not. In fact they sometimes carried a reduced bomb load to drop somewhere on a "target of opportunity" during their missions, not so much to hit anything in particular but more to spread alarm and despondency in the enemy’s rear.

Reconnaisance was carried out at three levels:

On 10.5.1940, when the attack in the West started, the Luftwaffe had 339 close recce or Nahaufklärer aircraft. In principle, every army corps and every armoured division had one Staffel with 12 Hs 126 (plus 3 liaison planes) assigned. The Hs 126 carried one fixed camera plus a handheld one, which the observer could use. Practical range was about 300 km. These aircraft played no role in the BoB but in the context of Seelöwe it was proposed to use them to lay smoke screens along the coastline to blind the defenders.

324 long-range reconnaissance or Fernaufklärer aircraft (mostly Do 17P and Ju 88A) had been available in May. These units worked for the Luftwaffe rather than for the army; by September, a Fliegerkorps typically had one or two Staffel assigned, for example the VIIIth Fliegerkorps (Richthofen) had 2.(F)/11 and 2.(F)/123 assigned for Seelöwe (according to Schenk, p. 231). On the 7th of September, Luftflotte 2 had six Fernaufklärerstaffel with 63 aircraft (51 serviceable), Luftflotte 3 had eight with 90 (58) aircraft, and Luftflotte 5 had four with 38 (14) aircraft (Collier, Defence of the United Kingdom, Appendix XVII). Towards the end of the BoB some Bf 110C-5 (with cameras in lieu of 20 mm guns) and Bf 109E-5 fighters were also used, which had a better chance of escaping enemy fighters. Like other Luftwaffe units, the Fernaufklärer were under strength by October. On the 5th of that month 1.(F)/123 operating from Buc near Paris should have had twelve Ju 88A with crews, but in fact had seven Do 17P and five Ju 88A, with four of each serviceable, and only five operational crews (H. Rabeder, Die Knullenkopfstaffel, p. 94).

The third level concerned strategic reconnaissance, carried out by the Fernaufklärungsgruppe der Oberbefehlshaber der Luftwaffe, commanded by Oberst Theodor Rowehl and based at Oranienburg near Berlin. Their main “customer” was Oberst i.G. Joseph “Beppo“ Schmid, the senior LW staff officer responsible for intelligence on foreign air forces, but they also provided the Abwehr with material (and dropped agents/spies of the Abwehr in Britain and Ireland). This unit used a variety of aircraft, fitted with cameras and long-range tanks and in some cases (Ju 86P) pressurised cockpits for high altitude flights (up to 12,000 meters). In the summer of 1940 the 3rd Staffel, equipped with eight He 111 and twelve Do 215B-4, was based at Stavanger, from where they regularly visited Scapa Flow and kept an eye on shipping movements. The 4th Staffel, also with Do 215B-4, operated over Britain from their base in Merville (near Dunkirk), while the 1st and 2nd Staffel - as far as I have been able to find out - were already in the east, systematically reconnoitring the Soviet Union from bases in East Prussia and later Romania.

Numbers in service remained relatively stable in 1940 it seems. Total production of recce aircraft in 1940 was 1079, including 368 Hs 126 (471 in total delivered up to the end of August), 38 Fw 189, 75 Me 110, 26 Bf 109, 6 Do 17, 92 Do 215, 330 Ju 88 and 36 Fw 200. Some existing Ju 86G were converted to JU 86P. In addition, 269 seaplanes were produced which also mainly engaged in reconnaissance (Ar 196, He 115, Do 18, Do 24, Bv 138).
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Knouterer
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Re: Operation Sealion - RAF and Luftwaffe Plans & Preparations

Postby Knouterer » 03 Apr 2018 10:18

Knouterer wrote:The MG-FF was a relatively low-powered 20 mm gun with a muzzle velocity of 600 m/sec (700 for the MG-FF/M; the 20 mm Hispano-Suiza gun coming into service with the RAF had a MV of 850-880 m/sec and delivered about twice the muzzle energy). It was therefore more suited for firing at bombers than at nimble fighters.


Of course, when they did hit, 20 mm shells did a lot of damage. This is a picture (from A. Saunders, Stuka Attack!) showing Spitfire X4110 of 602 Squadron, flown by Flt Lt Dunlop Urie on 18 Aug. 1940. Four shells exploded in (or against) the fuselage; the pilot's life was saved by his armoured seat but he was wounded in the legs by fragments. He managed to land at Westhampnett but the plane had suffered such structural damage that it was written off after an operational life of just twenty minutes.
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