Operation Sealion - RAF and Luftwaffe Plans & Preparations

[Knouterer]

You’d think that there is nothing new left to say about the RAF in the BoB period, but a recent book by Greg Baughen, The RAF in the Battle of France and the Battle of Britain, contains an interesting discussion of an under-utilized resource, namely, the many American aircraft that were arriving in Britain. The British were confident of the superiority of their own designs, but had ordered American planes of various types as an insurance against the possibility that the Luftwaffe might destroy the British aircraft industry. Days before France capitulated, Britain took over all armaments contracts with US firms, which at a stroke increased the number of aircraft on order to about 6,000.

Shipments of aircraft ordered by the French (and the Belgians) were diverted mid-Atlantic and by the end of June 26 Martin 167 Marylands and 16 Douglas DB7 Bostons had arrived. In July, they were followed by another 12 Marylands, 36 Curtiss Hawk fighters, 61 Northrop A-17 Nomad ground attack aircraft and 21 Brewster Buffaloes (Belgian order). The first assembled Buffaloes and Bostons were delivered to the RAF in the second week of July, the the first Hawks, Marylands and Nomads the following week.

This looks like a windfall, considering that the DB7, for example, was arguably the best light bomber around at the time, but the RAF was unenthusiastic about using these new planes. Bomber Command considered light bombers an unwelcome distraction from their main task, bombing Germany into submission, at which they thought (mistakenly ...) they were already having some success. Portal wanted to convert what remained of the Battle squadrons to “heavies”, even though no such bombers were yet available for them.

One problem was that these American aircraft, apart from being new types, had French instruments and controls, and also needed to be adapted to British guns, sights and bombs. However, there was a ready solution to the first problem, namely the Polish and Czech pilots in Britain who already in many cases had flown these aircraft in combat, notably the Hawk.

A quick census showed that there were 140 trained fighter pilots among Polish air force personnel in Britain, many of whom had already fought the Germans in two campaigns, but very little use was made of them initially. It certainly seems that good old-fashioned British prejudice against Johnny Foreigner played a role.

By the end of August, 60 Bostons and 40 Marylands had arrived and hundreds more were on the way. Forty-three had been assembled, fitted with armour, British guns and bombing equipment, and made ready for operations. But the only American bombers (apart from the Hudsons of Coastal Command of course) to become operational in the summer of 1940 were six Marylands sent to Malta for reconnaissance duties (first missions in September).

The Hawks and Buffaloes were no Spitfires but could out-turn it (and the Bf 109) in a low-level dogfight and would have been useful enough for ground support (perhaps fitted with bomb racks), reconnaissance, shooting down enemy recon planes, etc. Fighter Command might not have wanted such “oddball” squadrons in its tightly controlled organisation, but they could have been assigned to the “Army Co-operation Group” of Bomber Command (Lysanders). That the RAF could quickly integrate foreign airmen and aircraft – if it wanted to – is shown by the example of No. 320 (Dutch squadron) consisting of Dutch pilots who had escaped with their Fokker T.VIIIW floatplanes and within a few weeks were flying them for Coastal Command.

The A-17 Nomad was rather slow by 1940 standards, but as Baughen points out, the pilots who were expected to fly armed Tiger Moths, or obsolete Hawker Hinds, against the invasion forces (Operation Banquet) would gladly have taken them if given the choice. In the event, most of them were shipped to South Africa in 1941, where they were mostly used for target towing.

The first Martlets (F4F Wildcat in USN service) had also arrived by September, but none were in operational FAA squadrons yet.

[Knouterer]

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.

[Knouterer]

For the German speakers among us, a page from Wolfgang Fleischer, Deutsche Abwurfmunition im Zweiten Weltkrieg, Aachen 2015:

[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.

Literature:
Sönke Neitzel, Der Einsatz der deutschen Luftwaffe über dem Atlantik und der Nordsee 1939-1945, Bonn 1995.
Adam Thompson, Küstenflieger. The operational history of the German coastal air service 1935-1944, 2013.
Harold Thiele, Luftwaffe Aerial Torpedo Aircraft and Operations in World War Two, Hikoki Publications, Crowborough 2004.

[Sheldrake]

You’d think that there is nothing new left to say about the RAF in the BoB period, but a recent book by Greg Baughen, The RAF in the Battle of France and the Battle of Britain, contains an interesting discussion of an under-utilized resource, namely, the many American aircraft that were arriving in Britain. The British were confident of the superiority of their own designs, but had ordered American planes of various types as an insurance against the possibility that the Luftwaffe might destroy the British aircraft industry. Days before France capitulated, Britain took over all armaments contracts with US firms, which at a stroke increased the number of aircraft on order to about 6,000.

One of the truths of history is that creative historians will always find a new way to tell the tale to sell a book....

I suspect that there is more spin than substance in the neglected US aircraft story.

Just because an aircraft arrives in the Uk doesn't make the aircraft combat ready. They need to be checked, fitted with radios capable and pilots trained to use them. If it is an unfamiliar type someone needs to assess the aircraft and work out how to train pilots to fly it safely. The differences in controls between British and French aircraft controls wasn't simply metric versus imperial gauges. IIRC French throttle controls worked in the opposite direction to the British. A British pilot pulled back on then throttle to increase fuel to the engine the Frenchman pushed. That an instinctive movement to unlearn and not something an inexperienced pilot needed to think about consciously under stress.

The bottleneck in the battle of Britain wasn't the supply of aircraft frames but in trained pilots. The pilots tasked with flying against Op Sealion in Tiger Moths were from the flying schools using the aircraft they were trained to fly. Putting an inexperienced single engined pilot into a DB7 or Maryland was an invitation for them to kill themselves.

One of the assets of the RAF in the battle of Britain was the the civilian repair organisation. Many damaged aircraft were repaired and brought back into service or cannibalised. It made sense to fly British Aircraft that could easily be replaced or repaired.

The comments on the obsession of the RAF with bombing Germany miss the mark in 1940. RAF Bomber command played a significant role in the battle of Britain in what might now be described as battlefield interdiction, bombing the channel ports where the invasion fleet was assembling and attacking German airfields. Bomber command lost more men than Fighter command in the battle of Britain. No 2 Group was equipped with light bombers and would go on to use the DB7. Other groups were only equipped with the Fairey Battle as a stop gap because of delays in delivering enough heavy bombers.

[Knouterer]

The comments on the obsession of the RAF with bombing Germany miss the mark in 1940.

I don't think so - even at the most dramatic moments of the campaign in France Portal kept insisting that the most valuable contribution Bomber Command could make was bombing the Ruhr. Of course it also attacked other targets, notably the Channel ports and the Luftwaffe airfields in France in September/October, but even when invasion seemed imminent, some bombers were still sent all the way to Berlin and Dresden, where any damage they did was mostly psychological. Sunday 22 Sept., for example, was a fairly active day with happily (for the RAF) no losses.
Page from L. Donnelly DFM, The Other Few:

[Sheldrake]

The comments on the obsession of the RAF with bombing Germany miss the mark in 1940.

I don't think so - even at the most dramatic moments of the campaign in France Portal kept insisting that the most valuable contribution Bomber Command could make was bombing the Ruhr. Of course it also attacked other targets, notably the Channel ports and the Luftwaffe airfields in France in September/October, but even when invasion seemed imminent, some bombers were still sent all the way to Berlin and Dresden, where any damage they did was mostly psychological. Sunday 22 Sept., for example, was a fairly active day with happily (for the RAF) no losses.

Well. What do you expect. Portal commanded Bomber command, established as a strategic bombing deterrent. But No 2 Group were always a light bomber force committed to more limited targets and supporting the land battle. Furthermore, bombing Berlin did have positive outcomes on the Battle of Berlin. However ineffectual the physical damage, British Bombers over the Reich was a psychological blow.

[sitalkes]

Anything other than a strategic bombing attack on Germany was called a "panacea" attack; very few raids were launched against the invasion ports, they weren't raided until invasion seemed immanent, and the damage caused was only a nuisance to the Germans (aboub 10% of the barges were lost but there was already an excess so it wouldn't have hindered the invasion).

[Knouterer]

Can't quite agree with that assessment, until early September there wasn't much to bomb in the Channel ports but after that Bomber Command and Coastal Command visited almost every night with up to 150 aircraft or so, and caused widespread damage. The lost barges could be replaced, but not the transports, of which twelve were lost to air attack up to 21 Sept. (according to Schenk). On the night of 14/15 Sept. for example several ships were hit in Antwerp Harbour, the hull of A30 Rolandseck was ripped open by near misses and the engine room was flooded.
Photo source: http://www.ddghansa-shipsphotos.de/rolandseck400.htm Note the wooden platform for a light AA gun at the stern.

[Knouterer]

Page 60-61 of Lawrence Paterson, Schnellboote. A Complete Operational History (Seaforth Publishing, 2015). Showing that even before the Battle of France was over, the RAF, or in this case the Fleet Air Arm (not Coastal Command as the author says), was acting aggressively against enemy-held Channel ports, even in broad daylight. The reference to Blackburn "Rocs" is a also a mistake I think, the Roc was a fighter, even if it could carry a few bombs; 801 Squadron was equipped with Skuas.

[Knouterer]

The above account, by the way, seems inaccurate as regards the bomb load of the Skua and/or the Roc. This Wikipedia article claims that both types took part in the attack: https://en.wikipedia.org/wiki/Blackburn_Roc

[Orwell1984]

The reference to Blackburn "Rocs" is a also a mistake I think, the Roc was a fighter, even if it could carry a few bombs; 801 Squadron was equipped with Skuas.

In June 1940, 801 Squadron FAA was flying a mix of Skuas and Rocs, a situation that existed for a very short time. Page 161 of Sturtivant's The Squadrons of the Fleet Air Arm states that the Skuas were joined by a small number of Rocs: "the strength was increased by 6 Rocs in June [1940], but these were soon replaced by further Skuas" as the Roc was a failure as a fighting aircraft. One 801 Squadron Roc was lost on operations on June 21 1940. According to Peter Cornwell's Battle of France Then and Now [p496], a Roc was shot down during dive bombing attacks on gun postions at Cap Gris Niz. Lt. AVM Day and Naval Airman F Berry both with missing presumed killed in Aircraft H. Presumed lost to ground fire though a claim from Oberfw Buhl of 1.(J)/LG2 is also mentioned as a possibility. As to the Eboat attacks Paterson mentions, this is described on page 73 of Matthew Wills' book Blackburn Skua & Roc:

At around 1235 hours the Skua and Rocs divebombed the harbour where the E-boats were moored and strafed the boats themselves.

Included on page 74 of the Wills book is a picture of a formation of Rocs with the one closest to the camera peeling off in a dive bombing run. The caption notes "Whilst primarily intended as a fighter, the Roc could carry 660 lb of bombs under its wings. Rocs were used by 801 Squadron to dive bomb targets in France during the Dunkirk evacuation"

A good website with information of the Roc and its operational history is here:
http://dinger.byethost5.com/blackburn_roc.htm

Information on the bombload from the site:

Armament: four 0.303 Browning machine guns with 600 rounds per gun housed in electrically operated turret. Two 250 lb "B" or "SAP" bomb or 100 lb anti-submarine bomb could be carried (one beneath each wing) and a standard RAF light series carrier bombrack could also be fitted beneath each wing. Each carrier could hold 4 x 20 lb or 2 x 40 lb bombs or incendiaries. Thus the potential total bombload of the Roc was 660 Ibs.

Given the already shaky performance of the Roc, this is not something I'd have liked to try!

[Knouterer]

One problem facing the Luftwaffe fighter units in the context of Seelöwe was that not only did they have to defeat Fighter Command; at the same time they had to conserve sufficient strength to provide permanent fighter cover over the invasion zones during daylight. Whatever the Luftwaffe did, the British bomber forces would still be largely intact on S-Tag, given that bases of Bomber Command were well to the north of London and out of range of the Bf 109, and unescorted bombers attacking them were bound to suffer heavy losses, if they got through at all.

Generalmajor Theo Osterkamp, who at the end of July had been promoted from commander of JG 51 to Jagdfliegerführer 2, in charge of all the fighter aircraft of Luftflotte 2, calculated that in order to provide adequate fighter cover over the landing beaches two Geschwader, or about 150 fighters, would be needed (one each for the 9th and the 16th army zones). On the basis of three sorties per day, that would mean that in total twelve Geschwader, or about 900 aircraft, would have to be available. That was a bit more than the Luftwaffe actually had before serious fighting had even started. Other sources mention one Gruppe per beachhead, or four in total. At the beginning of July Osterkamp told the pilots of JG 51 that in order to achieve the required air superiority they would have to shoot down five enemy fighters for every one they lost (Bungay, The Most Dangerous Enemy, p. 126).

As JaFü 2, Osterkamp had available Jagdgeschwader (JG) 3, 26, 51, 52 (III. Gruppe in Germany) and 54, with 513 Bf 109 as of 13 Aug., of which 460 serviceable.

In addition, Fliegerkorps VIII (transferred from LF 3 to LF 2 at the end of August, after the Stukas were withdrawn from the fighting) had Lehrgeschwader (LG) 2 (no Geschwaderstab, two independent groups), with I. Gruppe with 39 (31 serviceable) Bf 109 on 13 Aug., flying from Calais-Marck. Hans-Joachim Marseille was assigned to this Gruppe, which claimed 92 victories during the BoB, for 22 aircraft lost and 16 damaged. It lost 10 pilots killed and missing and four POW. II/LG 2 (Schlachtflieger) had been equipped with Hs 123 until July/August, then converted to bomb-carrying Bf 109E-4. Started operations from Saint-Omer on 6 September 1940, losing two aircraft to flak over the Thames estuary (the term “Lehrgeschwader” by the way did not refer to a training unit as may be supposed, but rather to a specialist unit experimenting with new equipment and tactics under operational conditions, and giving demonstrations).

The famous Erprobungsgruppe (Erpro) 210 also belonged to Luftflotte 2 (II. Fliegerkorps) and had two Staffeln with Bf 110 (26/21 on 13 Aug.) and one with Bf 109E-4 (10/9) fighter bombers.
Finally, Luftflotte 2 had a nighfighter Geschwader (expanding to a division) under command, with about 90 Bf 109, Bf 110, Ju 88C and Do 17Z, based at airfields in Germany and the Netherlands.

Luftflotte 3 was the weaker partner with only three Jagdgeschwader, JG 2, 27 and 53, with 347 (303 serviceable) Bf 109E as of 13 Aug.

In addition, both Luftflotten had Zerstörergeschwader equipped with Bf 110 (ZG 26, two Gruppen of ZG 76, and V./LG 1 in LF 2, and ZG 2 in LF 3) which suffered badly in the fighting and had less than a hundred serviceable aircraft left in all by the end of Sept. II and III/ZG 76 together could put only 13 aircraft in the air on 27 Sept.

Luftflotte 5 in Norway had JG 77 with 85 (79) Bf 109 at Stavanger/Trondheim as of 13 Aug., but these were out of range. However, I/JG 77 was sent to France as reinforcements and was attached to JG 51, flying from Marquise (near Calais) from 25 Aug.

Robin Prior (When Britain Saved the West, 2015, p. 230) has a table showing a Luftwaffe strength of 933 serviceable single-engine fighters on the 10th of August, steadily dropping to 755 on 14 sept. and 667 on 5 Oct. These numbers refer to the (combat units of) the whole Luftwaffe, so somewhere between 100 and 150 serviceable Bf 109 have to be deducted from these numbers for fighter units in Norway (JG 77) and defending the airspace of the Reich (III/NJG 1, II and III/JG 52). A quiet period would have allowed the ground staff to catch up with maintenance and repair, and the number of serviceable aircraft would then have gone up, but given the many tasks the LW had to carry out immediately before the invasion, that was not likely to happen. Production of the Bf 109 ran at about 140 per month at this time, less than half the number of Hurricanes and Spitfires coming off the production lines each month.

Map is also from Bungay; inset shows how the Jagdgeschwader were crowded together near the Pas-de-Calais, so they could spend a maximum of time over England. This area became even more crowded from the end of August when the Stukageschwader (circled) of Richthofen's VIIIth Fliegerkorps moved in, as mentioned above. This meant that units had to operate from any reasonably large and level surface they could find, including recently harvested stubble fields.

[Bergedorf]

Hi,

according to german documents, the Luftwaffe had only 712 in all servicable Bf 109 in the Jagdverbände on 28th September 1940. The number of servicable aircrews was even less at 676 aircrews, and when you take the miniumun of aircraft and aircrew you only have 606 combat ready Bf 109 on 28th September 1940. And this number includes the planes stationed ind Germany, Norway or Denmark...

The ability of the german Luftfwaffe to secure the landings of operation Seelöwe would be very limited...

[Knouterer]

I agree, and if the Luftwaffe in the course of September had concentrated on defeating Fighter Command and achieving local air superiority - a prerequisite for launching the invasion at all - by attacking its airfields in the south-east of England, instead of bombing London, losses of both bombers and fighters would have been even heavier than they were in reality. In that case, it seems likely that by the end of Sept. no more than about 500 serviceable Bf 109 (with pilots) would have been available at the front, quite possibly fewer.

In case anybody wonders where Luftflotten 1 and 4 were, they did exist, in the eastern parts of the Reich and recently conquered territories, but did not at this time have any combat units under command as far as I can make out, just reconnaissance squadrons, meteo flights (Wettererkundungsstaffel), and such.