Germany develops in-flight refueling.

While I have only periferrially commented on this thread, it is clear a more definitive comment is required:

In the 1939 - 40 period what aircraft are the Germans using as tankers? The Fw 200 exists in tiny numbers as a transport. The Ju 90/290 doesn't exist. None of the large flying boats like the Bv 222 exist.
As we know already, a Ju 88 or He 111 takes about 3 to 4 tons of fuel fully loaded ( I think 2900 liters was mentioned earlier = 2.9 metric tons). Whatever the aircraft chose as a tanker it is likely only to be capable of refueling one to three aircraft at most; at least in 1939 - 40. This means the Germans have to provide one tanker per two strike aircraft for this mission profile.
So, all of a sudden the Germans need to provide a large number of dedicated tankers to their airforces to perform long range missions. These aircraft will cut deeply into the number of bombers and other larger types the Germans have in service.
The bottom line here is that a large (numerically) strike is impossible for the Germans to carry out using this method. They simply lack the crews and planes to make it happen without dire consequences to other Luftwaffe operations.

 

Great post I really like it.

 

This will be my last post on this thread till I study for my exam tomorrow. I would hope that by taking the time to do all the editing for these screen shots (and making as easy to copy and reuse image readily available for others), that perhaps someone will take the initiative to show me where they disagree. Maybe then I'll at last "get it".

The first image can be reused for a pictorial refuting of my points, and the second shows my points.





This first pair shows a close up of the channel area, and has a crude hand drawn set of circles apx 100 mile radius, that we can use as a visual aid for showing air search radar with such a range. If the actual ranges for 1939-1940 era sets are longer or shorter, post by how much and I can post an edited version later tonight.





This second pair has circles apx 250 miles in radius (to show the apx max interception range of a Hawker hurricane based at an airfield near the center). The very crude yellow lines (with scale superimposed), is one possible flight path (this one is 1800 miles long, one way). We need to start crunching the numbers before we waste any more time with counter measures, detection means, etc...

Basically, lets first discover whether of not MAR/DT techs could have allowed any of the historical bombers to have reached far enough out to hit the convoys in the first place. Then we can worry about how much fuel it is going to take, and how much a tanker can carry (and how far/fast), and only then figure out how the Brits would attempt to counter this strategy.

Also, by just looking at the second map, it appears that planes based out of Norway would have a shorter flight, and could possibly have hit the convoys the French based planed could not reach. Interesting.

I'll be back later tonight, hoping to find some good use of visual aids!

 

Especially vs formations the radar horizion is more of a determinat of effect range than power. Here's a url that callculates it for you.
Horizon calculator - radar and visual
If the planes are at 10,000 feet and the radar antena is at 10 ft the range is just under 150 miles if the antenna is at 100 ft the range goes up to 165 miles. The antena hieght is the height above sea level.

I doubt you'd see Hurricanes based out of Eire.

Now draw your circles around airbases in Northern Scotaland and Ireland. If the need arrises a radar installation in the Faroes wouldn't be that difficult to arrange. An airfield was built in 42-43 but timing could be moved up on that as well and that will pretty well close off attacks coming out of Norway.

The fighter version of the Mosquito could also have been accelerated a few months and it would give you an intercept radius of at least 300 miles. It would have been pretty leathal against LW bombers as well. If they went with a single pilot and took out the .303s they would gain a bit more range as well.

 

Here's a list of Chain Home stations:

The Radar Pages - Chain Home

At 20,000 feet the range is about 125 nm. At 30,000 its about 150 nm. At 10,000 its about 100 nm.

 

Where did you get your numbers from? They vary considerably from those of the calculater I linked. Not sure if it's a frequency difference or what.

 

Posting on my lunch break...
A couple of nice posts, but I got to keep studying for my tests, so just a quick response for now.

I didn't want anyone telling me, "well, if your were to base closer, then you could intercept further out.

Yea, but based on the range of the radar (a bit longer than I had thought, I'll admit), if the aircraft are going to be staying well outside of the apx 250 mile interception range of the Hurricanes, and thus about 100 miles south of best case radar detection, the chain home system will never even see them. I will, later tonight, post some fighter circles in Scotland and N. Ireland, but suspect a fighter base in the Faroes will prove to be the better option. Still, without radar coverage being able to tell you about a distant raid, interception will not be a straightforward affair.

Yep, I'd say between 300-400, and if we say it's in service as soon as the whether clears in early 1941 (perhaps the latter half of feb), it would begin to help try to intercept some raids that were cutting things a little to close to the UK, up until they get called away for Barbarossa. I'll add those in for tonight as well.

Based on this info, it looks like chain home, while very effective in the case of the traditional BoB, really isn't going to be a player in the hypothetical "battle of the Atlantic/BoB". And as the Germans are going to be flying outside the expected range of the land based fighters, and their range is at least 100 miles longer than that of the radar stations, we can dismiss them from consideration.

So we need to first focus on what the tankers are going to be able to do performance wise, their TTF loads, and stuff, and then we can look for what would be a good counter (I'm thinking radar equipped aircraft, but have no idea when the first became available).

T. A. Gardner, you mentioned a possible maximum fuel load of 20-22 tons, do you have any thoughts on the speed and range of these heavily laden tankers, and time it might have taken for such a tanker to transfer its load?

 

What, are you guys still playing at "Let's make the Jerries win WW2 in the Twilight Zone" ?

 

Mine come off the lobing pattern and fade chart for the CH radar published in the GEH Journal of Research. I figure that the actual performance figures for CH are a tiny, little, itsy bitsy bit better.... but hey! What do I know.....

 

I mentioned that as a likely maximum for a BV 222. But these flying boats don't exist until 1941 or so as even flying prototypes. Even then, no more than what you could count on the fingers of one hand were in service at any given time after that. They proved extremely vulnerable to interception and historically had to have a heavy escort for transport flights over contested air space.
As for pump rates this would depend on several things:

The size and type of pump
The size of the line used for transfering the fuel
The maximum pressure the line and receiving aircraft's fuel system could tolerate.

I suppose with 1940's technology that 100 liters a minute / 25 gal a minute might be achieveable without undue difficulty. That would then mean that a Ju 88 could refill (say 75% in about 20 minutes). That would be too long to be practical so the system would have to roughly be capable of double that or about 200 liters a minute / 50 gallons a minute.

Another item that needs to be addressed is how many aircraft can refuel at a time? I'd assume it is one simply because of the lack of knowledge and experiance with this sort of system the Germans would start off with.

 

Why the attitude? I wasn't even saying my values were better I just wanted to know where you got yours. It looks like we are actually looking at two different things. The calculator I linked to shows the radar horizon. Your figures are what based on a signal strength of one (?) of the actual radars?

 

That depends on how high they are flying. I'm not sure where their most economical cruising altitude is. The big thing though is forcing them well out to sea represents a significant navigation problem for them and increases the distance they have to fly. They can also evade Chain home by flying lower but at some point that consumes more fuel. Navigation wasn't anywhere near an exact science back then either, especially over open ocean.

 

Its been one of those days...

 

Radars were new back then and often the range would be cut in half due to atmospherical disturbance. They were just not reliable at extreme ranges. Anyway they would have to have range of well over 200 miles to detect these Condor missions that skirted around the UK. At those ranges the minimum radar elevetion would be many thousands of feet, so the patrol planes would be simply 'flying under the radar'. You know curvature of the Earth and all that.

CVE patroling that close to the German controlled territory in 1940-42 would be sitting ducks, to combind strikes and would just not last long....thats just wishful thinking.

The only reason the Condors stopped flying was because Goering swore they would NEVER be assigned to Donitz ever again. The only reason Donitz got them in the first place was because the 'stupid fat man' was out hunting when the issue was raise with Hitler.

The weather over the North Atlantic is bad most of the year so to hunt for convoys you'd have to operate under the cloud cover. It also means that just sending out long range fighters out to patorl air space offers little chance of actually finding any patrol bombers that far out to sea. You'd have to send out a lot of planes to find just one.

BTW ; This whole thread is based on a WI about inflight refueling.

 

I see, In reality radars are very useful gadget as well in games. Nice story

 

the mid flight refueling was invented by either the British or the Americans by Pilot Smith in 1923,17 years before ww2 even started.
even if the germans adopt this action during ww2,germans will not have the same experrence as the Allies had for 17 years worth,and they had never used an aircraft carrier to pratice runway take off's and sea landings. so ,if the germans did dicide to to what the allies did,first have to build aircraft carriers and no german had any practise,would not benifet the germans unlike the Allies.

 

The point is, radar coverage from Britain would have forced the German bombers (whatever they were) to fly many hundreds of miles further than they would have otherwise, largely negating any advantage from in-flight refueling. Flying under the radar would have had pretty much the same effect.

As for CVE's patrolling the Bay of Biscay, they could be covered by land-based fighters, so combined surface/air strikes aren't going to be effective against them. In any case, they don't have to be CVE's, they could be radar pickets that could detect the aircraft soon after they take off and alert British long range fighters. It's just one way of countering these long range strikes.

I suppose you have some authority to cite on this issue? I believe there were other factors, as well.

A very good point.

The obvious answer is radar. Unfortunately, the Germans didn't have the airborne Hohentweil version (equivalent to British ASV radar) until the spring of 1942, The British CVE's were, however, equipped with quite good air search radar in 1940, which could detect in-coming raids at about 100 miles or better. So the fact is, German bombers would be bumbling about in thick clouds trying to find convoys, while defending British Wildcats would be vectored onto them while they were still some distance from the convoy. Not a very good thing for the Germans.

As a matter of fact, German FW 200 Kondors did fly far enough to the west of Britain to bomb Allied Convoys. They did manage to find a few, though they seldom managed to report the positions with enough precision to lead U-boats to them. The Kondors did manage to bomb some ships, using very low-level approaches that were necessary to insure a hit (These tactics, of course, also insured that even 20 MM and rifle-caliber MG's were effective against the Kondors). And the British did manage to vector Widcats, launched from a CVE onto them and shoot them down. This raises the question of why in-flight refueling would be necessary for German aircraft to be able to attack Allied convoys?

The Germans were aware of in-flight refueling technology, but chose not to utilize it. Why was that? They obviously felt the benefits did not outweigh the costs. Another reason, in my opinion, was that they simply did not have enough aircraft available to make in-flight refueling pay dividends. Equipping the aircraft with the required hardware, building the tanker aircraft, training the pilots and aircrew, devising means of precision long range, over-water navigation, and committing the squadrons of bombers to anti-shipping duties, was far beyond the costs the Germans were willing, or able, to pay in resources and effort. The fact that the Allies could have easily countered such effort by escorting convoys with fighter-equipped CVE's was probably also a factor. Finally, I think the Germans relized that flying over the md-Atlantic, with it's predictably bad weather just wasn't worth what it was going to cost in lost pilots and planes.

I see seven reasons this wasn't a practical idea;

1. The Germans never were able to produce the specialized planes in sufficent numbers to make it work.

2. Effective anti-shipping strikes against Allied convoys simply would have provoked effective counters in the form of CVE escorts.

3. The Germans had no effective means of predicting Atlantic weather which would have led to excessive attrition of planes and pilots.

4. Until Spring, 1942, the Germans had no airborne search radar which would have made searching for Allied convoys in the Atlantic impractical.

5. Air attack on moving ships during WW II proved ineffective unless the aircraft attacked at such low levels as to invite effective return fire from even small caliber AA weapons easily carried by even the smallest freighters.

6. There was no such thing as precision over-water navigation during WW II, and this would have led to excessive operational losses of aircraft and pilots as well as ineffective strikes against Allied convoys.

7. There was no political will within the Luftwaffe to attempt the interdiction of allied convoys, which was seen as the Kreigsmarine's task.

 

Duplicate post

 

Indeed the best way to counter these raids if they developed would probably be a string of radar pickets that run SW from the western tip of Cronwall. One every hundred miles or so should be enough. 4 or 5 ships would extend the radar coverage out far enough to pretty much spot any of these raids. A couple of CVEs say 150 miles NW of the line would allow fighters to be launched to intersept the raids.

 

Its not that difficult to plan and mount a coordinate strike between UBoats, Surface flotilla and Condors on any given CVE, sinces its radar signature would be visible 2-3 times its range at altitude.

Air craft to draw off the the bulk of the fighters and surface forces to draw off the bulk of the naval escorts, leaving the CVE and a couple of escorts sitting ducks for a Wolf Pack.

Read Claasens "Hitlers Northern War..." about Goering and the Condors.


BTW at 125km the LOS of the earth is around 1 km [~ 1/2 °] and radar is bad at these boundry layers, so the general rule of thumb is about 2-3°, since returns are bad. Thats more like 2-4 km altitude @ 125km range. So these patrol bombers could approach to within a 100km of the UK undetected in that range band. The same thing would be true of any CVE, they could approach to nearly 50km at altitude of around 1-2km without being spotted.

How high is cloud cover in the rough Atlantic weather?