You do know that you are trying to argue in a circle? And why quote authors who support my position? (all speeds and times are imperial measurement units for the metrically disinclined).
I’ve had a quick read through the four books I have by Dr Alfred Price (The Hardest Day, The Luftwaffe Data Book, Battle of Britain and Blitz on Britain) and as far as I can tell he doesn’t once mention that London is the limit of the Bf109s range only that the combat range is 125 miles. He does give details of the first raid on London on 15th September where the 109s had to turn back on the outskirts of London because of adverse conditions. On this particular raid the bombers took longer to form up due to cloud, there was a 90mph headwind and the formation had to conduct a running battle over Kent with 11 Fighter Command squadrons, all of which meant that the raid was more than 30 minutes behind schedule.
If you can find any other information either from Alfred Price or another author/historian that you feel is relevant please feel free to share.
You’ve stated before that Duxford is 50 miles north of London whereas a measurement using Google Earth shows it is actually closer to 40 miles north of London. By that reckoning you would say that Duxford is in fact at a range of 130-140 miles from the German fighter bases but that is not the true story. The direct route is actually just 110 miles unless the Luftwaffe decides to go crazy and detour to central London first. I’ve included a map that shows the relevant distances.
Average cruise speed is 6 miles a minute. 90 minutes = 540 miles. That seems to suggest a reach of 270 miles.
Rule of thirds. 30 minutes fly out, 30 minutes combat 30 minutes back. 180 miles one exclaims! Wait. Time to form up, get to cruise altitude and sortie as a tactical unit. Ten minutes. What's the tactical radius at cruise now? 120 miles. Sudden combat requiring military or war reserve power. DOUBLE your fuel consumption rate. 30 minutes at 120 miles becomes 15 minutes if you are lucky. The Germans found they usually had only 10 minutes at that reach.
QED. You haven't done the calculations and you don't understand what is happening.
Average cruise speed for the Bf109 was actually somewhere in the region of 4.5 miles per minute (max cruise speed is more like 5 miles per minute). 90 minutes = 405 miles (stated as 410 miles in most sources). And no that does not suggest a reach of 205 miles and that is not what I’m suggesting either.
The rule of thirds as far as I’m aware relates to fuel consumption rather than endurance, you use a third of your fuel for the journey to target, allow a third for possible combat and the final third for the return journey. This is after you’ve made a 20-25% allowance for take-off and landing. So following your logic of dividing the max range by 3 one would exclaim 137 miles! But that’s not how it works. So the actual time allowances are more like, at maximum range of 125 miles, 20 minutes for take-off and landing, 60 minutes to travel to and from target and 10 minutes for possible combat. Remember most combats were over and done with within 5 minutes as ammunition was the deciding factor in the length of a fight.
Let’s assume that II/JG51 at Marquise have been assigned the close escort task for a raid on Duxford, a distance of 111 miles. The fighters take off at 13:00 and climb to the required height of 10,000ft whilst circling above base awaiting the bombers which they join at 13:10 climbing to the same level as the bombers at 13,000ft as they cross the coast. The journey to Duxford takes 35 minutes assuming the bombers cruise speed is 190mph. The fighters try to maintain a speed of 230mph whilst zig-zagging around the bomber formation as any slower would make it impossible to accelerate to combat speed in time if they need to. Fuel consumption at this speed is reduced considerably BUT this saving would mostly be negated by the extra distance travelled in the zig-zag manoeuvres. The bombing run is completed by 13:50 and the return journey begins taking slightly less time as the bombers cruise speed has increased as the bombers are now lighter. The fighters return to base by 14:25, 85 minutes after they took off.
Okay so that’s ideal conditions, no combat involved which is highly, highly unlikely. Most likely there will be a combat phase somewhere around the Thames Estuary, if this is a heavy attack it could result in the whole formation turning right round and heading for home, no problems with fuel. If it is a light attack the close escorts job is to stay with the bombers and let the top cover deal with the threat, some of which may have to run for home after running out of bullets or receiving damage. Still no worries about fuel. Now in all likelihood there is a running battle to the target so more and more fighters are having to peel off mostly due to ammunition but possibly because of fuel the closer they get to the target. But this is why they increased the escort to the point where there three times as many escorts as bombers and why the Germans sent out further fighters to cover the final part of the withdrawal.
So yes I have done my calculations and I do know what is happening.