Crucial points of the Battle of Britain?

[stona]

Some very intersting and inciteful comments. Id say the turning point came about 1938 or so. Germany's decision to focus on tactical support made the LW unsuited to sustained air operations, in which direct support of the armies was not the focus. The things the LW did well were related to support of the army, whether that be CAS, air superiority over the battlefield or tacair ops just behind the front. Later in the war they were able to adaprt enough to make a decent showing of air defence issues, but on the offensive, they were simply out of their depth as far as taking and holding air superiority over a wide and deep area like SE England.

This can't be a turning point in the BoB because at this period (largely before 1938 ) the Germans were developing an air force to carry out precisely the things which you correctly say it did well. In the numerous surviving specifications and other 'doctrinal' documents this intention is made clear. There was never any plan to take on Britain. When such a need arose the German planning isn't just inept, it is sometimes laughable.
The Wermacht as a whole seems to have viewed crossing the English Channel as it would a rather wide river which the Channel certainly is not. The Duke of Medina Sidonia found this out in 1588 as he and his ships were swept past the Isle of Wight and the entry to the Solent!
Cheers
Steve

 

[vikingBerserker]

Well, it was raining bombs.

 

[pbehn]

Late 1940 Germany attempted to interdict British seaports via bombing. As previously discussed, WWII era Port of London was essentially in the center of town. So bombing the seaport with 1940s technology means some bombs will hit the city accidently. However London per se wasn't the target.

There was a German raider shed its bombs on London . Churchill ordered a raid on Berlin in reprisal. Adolph insisted that no bombs be dropped on London without his permission, so he gave permission. Maybe he provoked himself by issuing cast iron guarantees that Berlin would never be bombed.


The turning point for me is when the invasion was called off, the LW maybe could have done better as others have described but never came remotely close to defeating the RAF. They needed to destroy the RAF completely but were losing a war of attrition.

 

[stona]

The turning point for me is when the invasion was called off, the LW maybe could have done better as others have described but never came remotely close to defeating the RAF. They needed to destroy the RAF completely but were losing a war of attrition.

They did come close to defeating Fighter Command and particularly 11 Group. This despite their inept waging of the campaign.

It wasn't the RAF but ultimately the RN that had to be defeated to enable an invasion. The invasion, despite some expensive and time consuming planning, was never a viable operation. The Wermacht lacked the means and more importantly, particularly in the case of the Kriegsmarine, the will to launch it.

Vice Admiral Assman of the German Naval Staff summed up the attitude to 'Sealion'.

"Not one of the responsible persons was inclined to take a clear cut stand against the operation.........yet all felt relieved when, failing to gain air supremacy, they had a valid reason which justified calling off the operation."

He also wrote later.

"Naval Staff also appreciated clearly that air supremacy alone could not provide permanent security against vastly superior naval forces in the crossing area."

As early as 21st May, before the French capitulation, following a Fuhrer Conference, Raeder went to great lengths to emphasise the 'impossible tasks' involved in an invasion of Britain. He warned that some 'irresponsible persons' might use the invasion of Norway as a precedent. He was at pains to emphasise that a dash across the docile Baltic Sea in fast passenger liners, through the Denmark Gate, evading the British Fleet to seize and land in lightly defended harbours was not the same as a large scale, opposed, crossing of the English Channel.
Later on 19th July 1940, in a memorandum sent via the Naval Staff, Raeder reiterated these arguments and others against the invasion forcefully to Hitler.
By 10th September 1940, as evidenced by an entry in the Naval Staff war diary, days before the official cancellation, it is clear that the Kriegsmarine is relieved that 'Sealion' is no longer even an option.

"It would be more in the sense of the planned preparation for operation 'Sea Lion' if the Luftwaffe would now concentrate less on London and more on Portsmouth and Dover, and on naval forces in or near the operation.
The Naval War Staff, however, does not consider it suitable to approach the Fuhrer now with such demands because the Fuhrer looks upon a large scale attack on London as possibly being decisive. Bombardment of London might produce an attitude in the enemy which will make the 'Sea Lion' operation completely unnecessary."

For the Germans the Battle of Britain WAS Operation Sea Lion, the battle that was never fought. In the years prior to 1939 there had never been a need to plan for it and no advantage that the Luftwaffe might gain over the RAF could make up for a lack of long term naval preparation. The RN was still the primary obstacle to invasion and, as Assman wrote, "everyone concerned with the operation knew this."

If you extend a turning point retrospectively, as Parsifal did for the Luftwaffe, I would suggest that the lack of long term naval planning, to enable the Kriegsmarine to confront the RN was a more crucial historical point. Nothing the Luftwaffe could ever have done could have facilitated the invasion.

Cheers

Steve

 

[pbehn]

They did come close to defeating Fighter Command and particularly 11 Group. This despite their inept waging of the campaign.

."[/I]

For the Germans the Battle of Britain WAS Operation Sea Lion, the battle that was never fought. In the years prior to 1939 there had never been a need to plan for it and no advantage that the Luftwaffe might gain over the RAF could make up for a lack of long term naval preparation. The RN was still the primary obstacle to invasion and, as Assman wrote, "everyone concerned with the operation knew this."

If you extend a turning point retrospectively, as Parsifal did for the Luftwaffe, I would suggest that the lack of long term naval planning, to enable the Kriegsmarine to confront the RN was a more crucial historical point. Nothing the Luftwaffe could ever have done could have facilitated the invasion.

Cheers

Steve

It depends on the meaning of defeat. The RAF and especially 11 group were very hard pressed but so was the LW. To mount an invasion or force a surrender by bombing the LW needed to sweep the RAF from the skies while having most of its air force intact, this they were never even remotely close to achieving, by the end of September the RAF was as strong as ever and the LW wasnt. I agree with almost all other points made. The LW wasn't formed to mount a cross channel invasion, with better planning intelligence and execution they could have done better, even pushed the RAF away from Kent but they would still be a long way from where they needed to be to either mount an invasion or force a surrender.

Re Radar, it would seem obvious that radar stations overlap, if the LW had pressed home many attacks on 3 adjacent stations they could have punched a hole in the Chain Home defence. I am a Brit who has read about the BoB and Radars involvement since I was a kid, it seems obvious now but at the time it wasnt to the German high command, though I am sure German pilots didn't believe they were intercepted by chance. They did take out some stations but the ggap wasnt big enough or there long enough for the advantage to be noticed and taken advantage of.

 

[Gixxerman]

I grew up believing that the switch to bombing London was the key turning point but I'm not so sure.

The prime reason the LW lost the BoB in my opinion is that they simply weren't equipped to with neither the tactics nor machinery nor manpower to do so.
Equally important is that they seriously underestimated the British political will to fight on - and I would also add the combined effect of the then British Empire Commonwealth to add to British capability.
Each side was guilty of poor estimates of the strength of the other, the LW grossly underestimated the RAF's abilities and the RAF overestimated that of the LW (which, in the end, was good for the RAF disastrous for the LW).

(when I say BoB I mean the air war, an actual successful invasion is a very different thing something I do not believe Germany could have 'won' even with periodic or day air-superiority over the south coast of England, they simply didn't have the ability to effectively deal with the British Royal Navy, nevermind that they lacked credible equipment to actually carry out the necessary operation and support the required logistical effort)

German output of both planes pilots was much lower than Britain's (this has always surprised me) the comment that they were fighting a war of attrition they would ultimately lose is correct, I think.

The radar issue too is surprising, Germany were leaders in radar in the late 30's early 40's, that they failed to fully appreciate the 'force multiplier' effect of a properly integrated defence system also surprises.
The poor recon also added to German woes in addition to the British 'XX' successes, they were being led up a blind alley (although XX would be more important later).

Stephen Bungey's 'The Most Dangerous Enemy' shows the RAF never came close to the often claimed collapse (yes 11 Group came close to disaster but it was hardly 'the RAF') that it was the LW that was suffering unsustainable losses (losses which, along with the previous attrition would have serious effects in the Russian campaign in '41).
I tend to side with this view these days.
I have never seen it proven but I am inclined to think the BoB was something of a bluff that got out of hand thanks to the typical hubris of the then German leadership, they expected Britain to fall into line when shown enough of the threat of force started something that was hard to get out of.
I also have a sneaking suspicion some of this was to mislead Stalin too.

Bungay makes an interesting claim about how use of the Me110 as a fast strike plane could have yielded much better results for the LW than dive-bombers the mass bombing by He 111's (from the results of 'Test Group 210' (Erprobungsgruppe 210), but thankfully we will never know.

 

[parsifal]

yep, i have to agree gixxerman, and with the greatest respect Steve, I think you are overplaying or overstating the real crisis that beset FC by the end of August. 11 gp was indeed almost on its knees, but 11 gp is not the whole of FC. it was a big chunk of FC, and its problems were very real, but even a few days of respite would allow it to recover, and that simply wasnt enough time for the Germans to win total air superiority, knock out all the airfields, destroy the radar net, suppress the ports and coastal defences and get a sizable force lodged in South East England. They were months away from getting anywhere near that

 

[pbehn]

The Chain Home RADAR installations were primitive by the standards of 1940 so primitive the Germans doubted its usefulness. However it could detect and locate raiders position and approximate height and numbers. Its strength was in the fact that it covered the whole of the British coastline facing the LW and was integrated into what is now called a command and control system which of course the LW couldn't see.

 

[redcoat]

Yet the USAAF did target cities and in doing so decimated the Luftwaffe.

By shooting down the Luftwaffe fighters attacking the bombers, and this is exactly why Kesselring and his senior staff were urging a switch from attacking the airfields to London.
Their reasoning was that London was a target the RAF would have to defend, so the switch would bring the remaining RAF fighters into a battle where the escorting Luftwaffe fighters could shoot them down.
Unfortunately for the Luftwaffe, the 'remaining' RAF fighters were far greater in number than they had expected.

 

[redcoat]

Some very intersting and inciteful comments. Id say the turning point came about 1938 or so.

According to the author Stephen Bungay, the turning point was in 1915, with the first German air attacks on the UK. After that date the defence of Britain air space was always a major priority for the RAF.

 

[Hop]

There was a German raider shed its bombs on London . Churchill ordered a raid on Berlin in reprisal. Adolph insisted that no bombs be dropped on London without his permission, so he gave permission.

This is a bit of a myth. The first significant attack on London came on the 15th August when the Luftwaffe mounted a planned attack on an airfield in Croydon (they hit Croydon airport rather than Kenley, but both were in Croydon). 60 civilians were killed when bombs hit civilian buildings outside the airfield.

The next day the Luftwaffe attacked more targets in London, killing 15 civilians in Wimbledon.

A few days after that the Luftwaffe started bombing London at night. As Richard Overy puts it:

The raids on Berlin were in reality retaliation for the persistent bombing of British conurbations and the high level of British casualties that resulted. In July 258 civilians had been killed, in August 1075; the figures included 136 children and 392 women. During the last half of August, as German bombers moved progressively farther inland, bombs began to fall on the outskirts of London. On the night of the 18/19, bombs fell on Wimbledon, Croydon and the Maldens. On the night of the 22/23 the first bombs fell on central London in attacks described by observers as "extensive" and for which no warning was given; on the night of 24/25 August bombs fell in Slough, Richmond and Dulwich. On the night the RAF first raided Berlin, bombs fell on Banstead, Croydon, Lewisham, Uxbridge, Harrow and Hayes. On the night of the next raid on Berlin, on 28/29 August, German aircraft bombed the following London areas: Finchley, St Pancaras, Wembley, Wood Green, Southgate, Crayford, Old Kent Road, Mill Hill, Illford, Hendon, Chigwell. London was under red warning for 7 hours 5 minutes. The bombing of London began almost 2 weeks before Hitler's speech on 4 September, and well before the first raid on Berlin

I agree with Dave, the biggest was the switch from military to civilian targets. This allowed the RAF to rebuild.

Operational strength on 13 August, the day the Luftwaffe launched their offensive:


Jagdwaffe (Bf 109) - 853
ZG (Bf 110) - 189
Stukas (JU 87) - 286
KG (level bombers) - 1,008

RAF
Spitfires and Hurricanes - 579

BF 109 pilots fit for duty - 869 (1st August)
Fighter Command pilots and aircrew - 1,396 (10 August)

On 7 September, the day the Luftwaffe began all out attacks on London:

Jagdwaffe (Bf 109) - 658
ZG (Bf 110) - 112
Stukas (JU 87) - 133
KG (level bombers) - 798

RAF
Spitfires and Hurricanes - 621

BF 109 pilots fit for duty - 735 (1 September)
Fighter Command pilots and aircrew - 1,381

It wasn't the RAF that needed rebuilding. Fighter Command had pretty much maintained strength throughout the worst period of the battle. It was the Luftwaffe that desperately needed a change of tactics.

Pretty simplistic view, though, Milosh, considering the USAAF was targeting specific targets within the cities, not just the cities themselves - they didn't just swan over and attack Cologne for the hell of it to achieve victory

Sometimes they did. The USAAF began area bombing of German cities in the summer of 1943. Sometimes an area attack was the plan before takeoff, more often an area attack was the secondary target if the primary target was covered with cloud. Richard G Davis, the official historian of the USAF, says the 8th AF carried out more than 1 area attack a week throughout 1944 and 1945.

Id say the turning point came about 1938 or so. Germany's decision to focus on tactical support made the LW unsuited to sustained air operations, in which direct support of the armies was not the focus. The things the LW did well were related to support of the army, whether that be CAS, air superiority over the battlefield or tacair ops just behind the front.

The most numerous bomber in the Luftwaffe at the start of the war was the He111. The He111 had a range of around 1,400 miles. That's not a tactical bomber. The Luftwaffe had 780 of them in service at the start of the war. That's a strategic bombing force that dwarfed any other in the world at the time.

At the start of the war Bomber Command had 8 squadrons of Wellingtons, 6 of Whitleys, 8 of Hampdens, with about 12 aircraft per squadron, that's about 260 bombers roughly comparable to the He111.

They did come close to defeating Fighter Command and particularly 11 Group. This despite their inept waging of the campaign.

I've seen nothing to suggest either FC or 11 Group were "close to defeat". At the meeting on 7th September, hours before the Luftwaffe switched to London, Dowding talked of "preparing to go down hill". He also talked of his changes to squadron organisation creating enough pilots to "meet wastage greater than any incurred so far". Just before that meeting Park, commander of 11 Group, told his chief controller:

"I've been looking at these casualty figures and I've come to the conclusion that at our present rate of losses we can just afford it. And I'm damned certain the Boche can't. If we hang on as we are going, we shall win in the end"

These are not the views of commanders facing defeat. And that's despite the fact they greatly overestimated German strength.

There's no doubt the Luftwaffe was beginning to hurt Fighter Command, but that's not the same as bringing them close to defeat. At all times the Luftwaffe was much closer to defeat, although the RAF did not know it at the time.

I'm trying to help my daughter with her homework which has asked her for crucial turning points during the Battle of Britain.

Now I have a fair idea of how the battle flowed but I'm not really sure that I can locate the crucial points when the British won and the Axis lost.

Probably the only decisive "point" of the BoB came on 15 May, long before the battle began. Dowding opposed sending any more fighter squadrons to France, and the war cabinet agreed. If that decision had gone the other way Britain may have had too few aircraft and pilots left to defeat the Luftwaffe in August and September.

 

[stona]

yep, i have to agree gixxerman, and with the greatest respect Steve, I think you are overplaying or overstating the real crisis that beset FC by the end of August.

I'm only going by what Park and Dowding said to Evill et alter in that Bentley Priory meeting on 7th September. The critical shortage was in operational pilots. I've posted the figures many times in other discussions.

It was most certainly not the case that "by the end of September the RAF was as strong as ever".
This stems from a contention in the BOB pamphlet published during the war and from which many historians (who should know better) have quoted uncritically. Even Dowding himself felt moved to correct this particular assertion. He pointed out that Fighter Command was receiving four-fifths of Service Flying Training Schools (SFTS) output, overloading the OTUs with 80-90 pupils who they had to turn out at the end of a fortnight "as best they could."
Consequently about 120 pilots per week had to be brought up to standard in mainly 'C' class squadrons, each having 16 non-operational pilots each. Twenty such 'C' class squadrons were effectively non-operational. Dowding doubted that they would be capable of intercepting unescorted bomber formations.

At the end of October an 11 Group squadron had on average 19 pilots (establishment was 26) with plans to increase this to 24. There were few non-operational pilots still training in 11 Group (unlike the wonderful BoB film). 11 Group was still no stronger than in the critical late August-early September period when Dowding was forced to introduce the much despised stabilisation system, in his own words "a desperate expedient forced upon me by the heavy losses".
It would stay in place long after the British considered the battle over, into November 1940.

Fighter Command had enough pilots overall, a point the BoB pamphlet took at face value, but not enough fit to engage the enemy. In October 1940 roughly one third (440) of all Fighter Command pilots were non-operational.
Of the 231 pilots killed or seriously wounded between 24th August and 7th September about 50 were from 11 Groups pool of experienced flight leaders. Such men can not be replaced from OTUs and there were just not that many of them to begin with.

The Luftwaffe could have defeated the RAF with a different campaign, or at least forced it North of the Thames. As it was the campaign against Fighter Command enjoyed some success. Park wrote in a memorandum on 12th September that the Luftwaffe had "on several occasions barged through our first and second screen of fighters and reached their objectives by sheer weight of numbers."
It wouldn't have made the slightest difference to the outcome of the war at the end of 1940. Had it emboldened the Germans to attempt an invasion it might well have ended in catastrophe for them. I don't believe they would have made the attempt, other excuses not to would have been found, particularly by the Kriegsmarine, many of whose senior officers regarded the enterprise as pure folly.

Cheers

Steve

 

[pbehn]

I'm only going by what Park and Dowding said to Evill et alter in that Bentley Priory meeting on 7th September. The critical shortage was in operational pilots. I've posted the figures many times in other discussions.

It was most certainly not the case that "by the end of September the RAF was as strong as ever".
This stems from a contention in the BOB pamphlet published during the war and from which many historians (who should know better) have quoted uncritically. Even Dowding himself felt moved to correct this particular assertion. He pointed out that Fighter Command was receiving four-fifths of Service Flying Training Schools (SFTS) output, overloading the OTUs with 80-90 pupils who they had to turn out at the end of a fortnight "as best they could."
Consequently about 120 pilots per week had to be brought up to standard in mainly 'C' class squadrons, each having 16 non-operational pilots each. Twenty such 'C' class squadrons were effectively non-operational. Dowding doubted that they would be capable of intercepting unescorted bomber formations.
Cheers

Steve

Depends how you define strength. I am certainly not going to disagree with Dowding and Park (or even you steve) by the time in question the Stuka had been taken out of the game the Bf110 almost the same. All raids from across the North sea had stopped. Dowding and Parks point of view like the Germans was based on faulty intellegence. However as I and others have said The British overestimated the size of the LW at the start and its capacity to provide new planes and pilots. The LW front line strength was diminished and while you are correct in what you say about pilot quality in the RAF it was facing a much diminished threat from the LW who had similar problems. Dowding and Park didn't realize, or fully realize it at the time but that was why they were good, considering that the worst case scenario may actually happen.

To mount an invasion they needed to have air superiority over England while they actually didnt even have it over their own territory they were unable to fully protect the assembled bares in Antwerp for example. I agree with you and others though. Even if the capacity of the RAF was reduced to token defence an invasion still wouldnt have gone ahead, just one RN. Battleship among a fleet of flat bottomed barges would have been disaster.

 

[stona]

Raw numbers need careful analysis. Many historians just don't do this. From July to October 1940 the Luftwaffe lost 2,662 airmen, many times more than the British. They also lost 1,887 aircraft, substantially more than the RAF.

It is interesting to make a comparison of fighter losses (Bf 109 and Bf 110 for the Luftwaffe)

The RAF lost 1,023 aircraft, almost all Spitfires and Hurricanes. The Luftwaffe lost 873 Bf 109s and Bf 110s.

When we compare fighter crew losses the story is also different. The RAF lost 537, the Luftwaffe 551. Obviously some RAF fighters were shot down by bombers but the rather similar figures, bearing in mind that the Luftwaffe was operating over enemy territory and that the Bf 110 had two crewmen, tell an interesting story.

I'm just saying that raw data can be misleading and often needs careful interpretation. It's what good historians do.

My figures are from 'The Battle of Britain Then and Now'. The exact numbers vary very slightly from source to source but these are about as good as it gets

Cheers

Steve

 

[pbehn]

Raw numbers need careful analysis. Many historians just don't do this. From July to October 1940 the Luftwaffe lost 2,662 airmen, many times more than the British. They also lost 1,887 aircraft, substantially more than the RAF.

It is interesting to make a comparison of fighter losses (Bf 109 and Bf 110 for the Luftwaffe)

The RAF lost 1,023 aircraft, almost all Spitfires and Hurricanes. The Luftwaffe lost 873 Bf 109s and Bf 110s.

When we compare fighter crew losses the story is also different. The RAF lost 537, the Luftwaffe 551. Obviously some RAF fighters were shot down by bombers but the rather similar figures, bearing in mind that the Luftwaffe was operating over enemy territory and that the Bf 110 had two crewmen, tell an interesting story.

I'm just saying that raw data can be misleading and often needs careful interpretation. It's what good historians do.

My figures are from 'The Battle of Britain Then and Now'. The exact numbers vary very slightly from source to source but these are about as good as it gets

Cheers

Steve

Cheers steve thats as I remember the figures (I dont have any books here) in terms of a fighter against fighter conflict the LW won on points but the RAF was there to engage bombers which shows the LW lost heavily. However Bomber command also had quite substantial losses also which arnt normally counted in the BoB so on balance a stalemate of sorts which was all the RAF needed.

 

[GrauGeist]

It wasn't the RAF that needed rebuilding. Fighter Command had pretty much maintained strength throughout the worst period of the battle. It was the Luftwaffe that desperately needed a change of tactics.

The constant bombing of airfields and support infrastructure was most certainly taking it's toll on RAF operations, when the Luftwaffe shifted it's concentration away from these targets, it allowed the RAF to rebuild and reinforce it's assets.

 

[stona]

so on balance a stalemate of sorts which was all the RAF needed.

Absolutely, that's exactly what it was. Dowding said that he had only to avoid defeat until the weather turned in November. That's exactly what he did with his 'stalemate' and in so doing he denied the Germans their stated objectives which was in itself a victory of sorts (and not a Pyrrhic one, the cost was sustainable.....just).

I don't believe that the outcome prevented and invasion, and nor did Churchill who in his first reference to the Battle of Britain, on 18th June 1940, in the House of Commons referred to the resistance of the entire nation adding a cutting reference to "some people" forgetting that we have a Navy.
It is a part of the well know 'finest hour' speech.

"Here is where we come to the Navy. After all, we have a Navy. Some people seem to forget that. We must remind them. For the last 30 years I have been concerned in discussions about the possibilities of oversea invasion, and I took the responsibility on behalf of the Admiralty, at the beginning of the last war, of allowing all Regular troops to be sent out of the country, although our Territorials had only just been called up and were quite untrained. Therefore, this island was for several months practically denuded of fighting troops. The Admiralty had confidence at that time in their ability to prevent a mass invasion, even though at that time the Germans had a magnificent battle fleet in the proportion of 10 to 16, even though they were capable of fighting a general engagement every day and any day, whereas now they have only a couple of heavy ships worth speaking of."

None of this diminishes the efforts of the RAF in delivering an important rebuff to Nazi ambition and the heroism of those who fought it, on both sides, should not be forgotten.

Cheers

Steve

 

[Hop]

The constant bombing of airfields and support infrastructure was most certainly taking it's toll on RAF operations, when the Luftwaffe shifted it's concentration away from these targets, it allowed the RAF to rebuild and reinforce it's assets.

How badly was it affecting RAF ground operations?

In the past I've tried to quantify it. The hard data I've been able to find covers RAF aircraft destroyed on the ground and RAF personnel killed on the ground.

Fighter Command aircraft destroyed on the ground:

25 August - 20
28 August - 5
4 September - 4
25 September - 1

Not only are those figures low, they do not suggest any sort of escalation in the ability of the Luftwaffe to destroy FC aircraft on the ground. In fact they suggest the opposite.

RAF personnel killed on the ground (21 August - 5 September only):

21 August - 2
26 August - 4
31 August - 40 (according to Dowding all 40 were killed when a bomb exploded in a trench they were taking cover in)
1 September - 3

If the Luftwaffe were having a significant impact on RAF operations I'd have expected to see them inflicting increasing damage on RAF bases, as the RAF became unable to defend them properly. The statistics don't show that.

The other area I'd expect to see an effect is in serviceability rates. If the airfields were being heavily damaged, it should have made it harder to repair planes after combat, and decrease the serviceability rate. Air Commodore Peter Dye, from the RAF Historical Branch, gave 3 figures for Fighter Command serviceability rates:

An RAF study in 1945
July - 92%
August - 89%
September - 90%
October - 88%

The official history of the RAF:
Nov 1939 - 80%
Jul 1940 - 76%
September 1940 - 80% ("where it stayed for the remainder of the year")

A Fighter Command Research Branch study from 1949:

"the average number of serviceable aircraft per squadron across
11 and 13 Groups was in excess of 15 for the period July to October 1940."

Certainly the Luftwaffe did some damage to the RAF. But the statistics do not suggest it was particularly significant.

 

[pbehn]

How badly was it affecting RAF ground operations?

In the past I've tried to quantify it. The hard data I've been able to find covers RAF aircraft destroyed on the ground and RAF personnel killed on the ground.

Fighter Command aircraft destroyed on the ground:

25 August - 20
28 August - 5
4 September - 4
25 September - 1

Not only are those figures low, they do not suggest any sort of escalation in the ability of the Luftwaffe to destroy FC aircraft on the ground. In fact they suggest the opposite.

RAF personnel killed on the ground (21 August - 5 September only):

21 August - 2
26 August - 4
31 August - 40 (according to Dowding all 40 were killed when a bomb exploded in a trench they were taking cover in)
1 September - 3

If the Luftwaffe were having a significant impact on RAF operations I'd have expected to see them inflicting increasing damage on RAF bases, as the RAF became unable to defend them properly. The statistics don't show that.

The other area I'd expect to see an effect is in serviceability rates. If the airfields were being heavily damaged, it should have made it harder to repair planes after combat, and decrease the serviceability rate. Air Commodore Peter Dye, from the RAF Historical Branch, gave 3 figures for Fighter Command serviceability rates:

An RAF study in 1945
July - 92%
August - 89%
September - 90%
October - 88%

The official history of the RAF:
Nov 1939 - 80%
Jul 1940 - 76%
September 1940 - 80% ("where it stayed for the remainder of the year")

A Fighter Command Research Branch study from 1949:

"the average number of serviceable aircraft per squadron across
11 and 13 Groups was in excess of 15 for the period July to October 1940."

Certainly the Luftwaffe did some damage to the RAF. But the statistics do not suggest it was particularly significant.

Good figures and if you compare to the losses both in absolute terms (men killed aircraft lost) and general terms (men injured and aircraft damaged) the situation is a bit different. As I have read it the LW was getting smaller and so massed raids on the London were the last resort. In terms of men and machines (a body count) it was close , in terms of mounting an invasion it wasnt close at all.

 

[vikingBerserker]

from US Air Force Magazine How the Luftwaffe Lost the Battle of Britain

"The attacks continued relentlessly. On average, the Luftwaffe sent 1,000 airplanes a day, and seldom fewer than 600. On Aug. 30 to 31, more than 1,600 came. The worst day for Fighter Command was Aug. 31 when it lost 39 aircraft and 14 pilots. Most days the Luftwaffe's losses were even heavier than the RAF's, but the production of Hurricanes and Spitfires was no longer keeping up with losses, and there were not enough replacements for the experienced pilots who had been killed."

"An enraged Hitler on Sept. 5 ordered a change in basic strategy, shifting the Luftwaffe's focus of attack from British airfields to the city of London. That took the pressure off Fighter Command at a critical time. RAF fighter losses fell below the output of replacements. In diverting the offensive from the RAF, the Germans had lost sight of the valid assumption with which they had begun: The key objective was destruction of the RAF. Otherwise, the Sea Lion invasion would not be possible."