Ideal Luftwaffe starting 1/1/1936

[DonL]

The BMW 132 was on a continuous development also with fuel injection from 1934 till end of production.
To claim it was not or the BMW 801 influenced this development in a wrong way is totaly wrong. The development of the BMW 132 was the base of the 801.

The advertisement of a big radial engine was 1935 and totaly rational, because the BMW engineeres were specialist of radial engines and not liquid cooled engines since 1929, also the engineers from Bramo. Both companies were the most important engine companies from 1932-1938 of Germany and it was more then right and rational to integrate them in the development of high performance military engines.

A failure was the long wait of the fusion of both companies. Bramo was owned since 1935 from the RLM/Germany but no fusion with BMW till 1938 and no new engine factory till 1938/39. This was a big mistake. Fusion both companies at 1936 and funding a new engine factory at 1936/37 just as Junkers and Daimler Benz.
One of my personal important points to built a LW from 1936 onwards.

An other realy important point at 1936 to fund in agreement with BMW, Junkers and Daimler Benz, component supplier of modern all around production tools for development and to enlarge production of this tools.

Next points will follow.

 

[stona]

I don't think that there was much wrong with the Luftwaffe development between 1936 and the outbreak of the war. You can put any nations aircraft development under the microscope and pick holes in it.

By 1939 the Luftwaffe was equipped with one of the two best single engine fighters in the world, arguably the best dive bomber in the world, one of the best medium bombers in the world (if the Ju 88 wasn't THE best) and a pretty decent aircraft capable of taking on many different roles in the Bf 110. Others have already mentioned the Ju 52 which was also pretty good for its day.

I'd ask what exactly did the Germans do wrong?

Cheers

Steve

 

[wiking85]

I don't think that there was much wrong with the Luftwaffe development between 1936 and the outbreak of the war. You can put any nations aircraft development under the microscope and pick holes in it.

By 1939 the Luftwaffe was equipped with one of the two best single engine fighters in the world, arguably the best dive bomber in the world, one of the best medium bombers in the world (if the Ju 88 wasn't THE best) and a pretty decent aircraft capable of taking on many different roles in the Bf 110. Others have already mentioned the Ju 52 which was also pretty good for its day.

I'd ask what exactly did the Germans do wrong?

Cheers

Steve

Making the Ju88 a dive bomber, medium bomber, and the main bomber when it was designed as a fast, light, level bomber in 1935.

 

[tomo pauk]

By 1939 the Ju-88 was not in LW service. Even during the BoB it was used in just a few units. By 1939, the DB-engined Bf-109 were few and far between either. The more numerous Jumo-engined examples were decent, but nothing spectacular. The Do-17 was once before fast, adding 'features' cut the speed.

The spectacular succeses of LW prior BoB have much more to do with catching enemy at sleep, attacking the enemy that can't compete in number of A/C on disposal, quality of German crews, doctrine, cooperation, number of sorties, capturing enemy airfields by Heer, rather than with supposed great features of German A/C.

 

[DonL]

I don't think that there was much wrong with the Luftwaffe development between 1936 and the outbreak of the war. You can put any nations aircraft development under the microscope and pick holes in it.

By 1939 the Luftwaffe was equipped with one of the two best single engine fighters in the world, arguably the best dive bomber in the world, one of the best medium bombers in the world (if the Ju 88 wasn't THE best) and a pretty decent aircraft capable of taking on many different roles in the Bf 110. Others have already mentioned the Ju 52 which was also pretty good for its day.

I'd ask what exactly did the Germans do wrong?

Cheers

Steve

The advertisement of the Bomber B with a 2000 PS engine. This advertisement got the whole german engine development in the wrong direction.
The advertisement of the Bomber A with coupled engines and dive bombing capacity, also a big factor of the wrong engine development (coupled engines DB 606). No dive bombing for the He 177!

Too much focus of dive bombing at the Ju 88 and Do 217.
If dive bombing then only 50-55 degree, to be able pull out the bombs from the internal bomb bay.
Also dividing of the Ju 88 development, because the original intention was a fast bomber.

To prefer the Me 110 over the FW 187.

In summary this were very big mistakes and especially cost at least 3 years of engine develppment of the DB 603 and Jumo 213!

 

[Shortround6]

The spectacular succeses of LW prior BoB have much more to do with catching enemy at sleep, attacking the enemy that can't compete in number of A/C on disposal, quality of German crews, doctrine, cooperation, number of sorties, capturing enemy airfields by Heer, rather than with supposed great features of German A/C.

Some of the quality (experience)of the German aircrew came from the hundreds of He 111 bombers powered by DB 600 engines even if the planes themselves were no longer in front line combat service when the war started.

A small bit of the success/usefulness of the Bf 110 may also come from the long range radios they had.

 

[Shortround6]

In summary this were very big mistakes and especially cost at least 3 years of engine develppment of the DB 603 and Jumo 213!

I am not so sure about the delay in Jumo 213. While I have no doubt it caused some delay the original Jumo 211 ran at 2200rpm. You have to walk before you can run and getting the Jumo 211 up to 2700rpm is going to have to happen before you can get it up to 3250rpm. You also have to convince Junkers to get rid of that G-O-D awful supercharger impeller they were using and get at least into the 1930s with impeller design

Copying the Russian intake didn't hurt either. Trying to start the Jumo 213 earlier might have lead to a model using C3 fuel (higher boost) and less RPM which may mean the 1750hp version using B4 doesn't get their much quicker?

Did the DB 601N delay the 601E and 605?

 

[DonL]

By 1939 the Ju-88 was not in LW service. Even during the BoB it was used in just a few units. By 1939, the DB-engined Bf-109 were few and far between either. The more numerous Jumo-engined examples were decent, but nothing spectacular. The Do-17 was once before fast, adding 'features' cut the speed.

The spectacular succeses of LW prior BoB have much more to do with catching enemy at sleep, attacking the enemy that can't compete in number of A/C on disposal, quality of German crews, doctrine, cooperation, number of sorties, capturing enemy airfields by Heer, rather than with supposed great features of German A/C.

The production of the Bf 109 E1 began January 1939 and 1100 were built in the first 8 month of the year 1939.
Also the LW had the Ju 87, He 111, Do 17 and Ju 52 at the beginning of the war (1939) all in decent numbers.

Which other Air Force at 1939 had such aircrafts?
To my opinion you can rate the Ju 87,He 111 and Do 17 at 1939 as very good aircrafts (state of the art) also the Ju 52.

To claim this a/c's were average compare to other Air forces in 1939 is to my opinion wrong

 

[davebender]

He-177A.
He-177B.
Do-317.
Ju-288.

Late 1930s Germany cannot afford two heavy bomber programs. Bomber A and Bomber B programs should be combined into a single competition. Winner gets the entire level bomber contract.

 

[DonL]

I am not so sure about the delay in Jumo 213. While I have no doubt it caused some delay the original Jumo 211 ran at 2200rpm. You have to walk before you can run and getting the Jumo 211 up to 2700rpm is going to have to happen before you can get it up to 3250rpm. You also have to convince Junkers to get rid of that G-O-D awful supercharger impeller they were using and get at least into the 1930s with impeller design

Copying the Russian intake didn't hurt either. Trying to start the Jumo 213 earlier might have lead to a model using C3 fuel (higher boost) and less RPM which may mean the 1750hp version using B4 doesn't get their much quicker?

Did the DB 601N delay the 601E and 605?

To my sources and technical understanding the Jumo 213 is from the development steps and intention very simular to the DB 605.

Both the Jumo 211 as well as the DB 601 were both constructed without any knowledge or integration of pressurised water cooling. The engine block and head were constructed without this knowledge, especially the cooling lines through the engine. Both companies expiremented heavily from 1938 till 1940/41 with pressurised water cooling and integrated it in the Jumo 211 and DB 601. But this integration was limited through the construction of the two engines without any knowledge about pressurised water cooling. The limits were the DB 601E (2700 rpm) and the Jumo 211 F (2600rpm) both in production late 1940 early 1941.

Daimler Benz constructed the DB 605 with the knowledge of pressurised water cooling and other cooling lines for more power and better cooling.
To my understanding the Jumo 213 was constructed to the same parameters, new and better cooling lines through the engine for more and better power and cooling, this was the essential difference to the Jumo 211.

The Jumo 213 reached more power and especially more RPM then the DB 605 mainly through an other basic design philosophy (also Jumo 211), because he was heavier/more stable built and from much better alloys. The DB 605 was a save alloy engine, the Jumo 213 wasn't.

To my sources the first ideas of the Jumo 213 existed at 1938, first prototype engines were built at 1940, but as I mentioned before all at a smal priority. My idea and believing is that the Jumo 213 could also be developed in the same timeline as the DB 605, because both developments had the same intention and goal and the same timeline to get the knowledge. THe development of the Jumo 222 clearly prevented such a concentrated development of the Jumo 213.

The same development steps are necessary for the DB 603, because it was an enlarged DB 600 from the pantograph. If you develop a DB 603 from 1937, he would have had all the same steps as the DB 601 till the DB 605, but to my opinion there would much more time to do basic engine work, to sort out the reliable problems.

To my opinion there would be more work to develop the DB 603 (without reliable problems) as to develop the Jumo 213.

THe rest is tuning from the base, also an other supercharger or impeller, but both engines would be in production at 1942 and Germany had more time to change the production or parts of the production and could realy concentrate on the power output without intensive basic engine work to sort out any "basic" reliable problems.

Development steps Jumo 211:

Jumo 211A 2200 RPM released 1937
Jumo 211 B 2400 RPM released end of 1938
Jumo 211 F 2600 RPM released 1940

 

[DonL]

He-177A.
He-177B.
Do-317.
Ju-288.

Late 1930s Germany cannot afford two heavy bomber programs. Bomber A and Bomber B programs should be combined into a single competition. Winner gets the entire level bomber contract.

Bomber B is a fast medium bomber not a heavy bomber, read the advertisemnet, also the Do 217 was a medium bomber not a heavy bomber.

 

[stona]

To claim this a/c's were average compare to other Air forces in 1939 is to my opinion wrong

Exactly. The Luftwaffe in 1939/40, the war started in September, was equipped with some of the best aircraft in the world. It also had some of the best trained and certainly most experienced aircrew in the world. Across the board it was the best equipped of any air force.
Of course mistakes were made, everyone else made them too, but overall the Luftwaffe did pretty well.
The fact that no long term strategic planning was done, causing the Luftwaffe to come up short by the start of Barbarossa, is an entirely different subject, just as doctrinal (dive bombing or strategic bombing, the entire 'zerstorer' concept) questions are.
In the years leading up to the war the Germans produced some of the best aeroplanes and aero engines of their time.
Cheers
Steve

 

[davebender]

Terms such as "Fast Medium Bomber" and "Heavy Bomber" are beside the point. These type aircraft programs are expensive. 1936 Germany has resources to fund one of the programs properly. Or they can half fund both programs and get the historical results.

I vote for funding one level bomber program properly and cancelling the other. Pick one. It should replace the He-111 NLT 1942.

 

[wiking85]

To my sources and technical understanding the Jumo 213 is from the development steps and intention very simular to the DB 605.

Both the Jumo 211 as well as the DB 601 were both constructed without any knowledge or integration of pressurised water cooling. The engine block and head were constructed without this knowledge, especially the cooling lines through the engine. Both companies expiremented heavily from 1938 till 1940/41 with pressurised water cooling and integrated it in the Jumo 211 and DB 601. But this integration was limited through the construction of the two engines without any knowledge about pressurised water cooling. The limits were the DB 601E (2700 rpm) and the Jumo 211 F (2600rpm) both in production late 1940 early 1941.

Daimler Benz constructed the DB 605 with the knowledge of pressurised water cooling and other cooling lines for more power and better cooling.
To my understanding the Jumo 213 was constructed to the same parameters, new and better cooling lines through the engine for more and better power and cooling, this was the essential difference to the Jumo 211.

The Jumo 213 reached more power and especially more RPM then the DB 605 mainly through an other basic design philosophy (also Jumo 211), because he was heavier/more stable built and from much better alloys. The DB 605 was a save alloy engine, the Jumo 213 wasn't.

To my sources the first ideas of the Jumo 213 existed at 1938, first prototype engines were built at 1940, but as I mentioned before all at a smal priority. My idea and believing is that the Jumo 213 could also be developed in the same timeline as the DB 605, because both developments had the same intention and goal and the same timeline to get the knowledge. THe development of the Jumo 222 clearly prevented such a concentrated development of the Jumo 213.

The same development steps are necessary for the DB 603, because it was an enlarged DB 600 from the pantograph. If you develop a DB 603 from 1937, he would have had all the same steps as the DB 601 till the DB 605, but to my opinion there would much more time to do basic engine work, to sort out the reliable problems.

To my opinion there would be more work to develop the DB 603 (without reliable problems) as to develop the Jumo 213.

THe rest is tuning from the base, also an other supercharger or impeller, but both engines would be in production at 1942 and Germany had more time to change the production or parts of the production and could realy concentrate on the power output without intensive basic engine work to sort out any "basic" reliable problems.

Development steps Jumo 211:

Jumo 211A 2200 RPM released 1937
Jumo 211 B 2400 RPM released end of 1938
Jumo 211 F 2600 RPM released 1940

AFAIK the DB605 was mainly different via an increased bore size and larger displacement, while the Jumo 213 was the same displacement, built smaller, but with higher rpm.

https://en.wikipedia.org/wiki/Daimler-Benz_DB_605

The primary differences between the 605 and 601 were greater displacement, higher revolutions, higher compression ratio and a more powerful supercharger. Through careful study the engineers determined that the cylinders could be bored out to a larger diameter without seriously affecting the strength of the existing block. The difference was minimal, increasing from the 601's 150 mm cylinder bore to the 605's 154 mm, but this increased the overall displacement from 33.9 litres to 35.7. Altered valve timing increased the inlet period and improved the scavenging to give greater volumetric efficiency at higher speeds, which improved the maximum allowable RPM from 2,600 in the 601 to 2,800 in the 605. The combination of these changes raised power output from 1,350 PS (1,332 hp) to 1,475 PS (1455 hp). The engine was otherwise similar, notably in size, which was identical to the 601. However, its weight did increase from 700 to 756 kg.

In other ways the engine was essentially identical to the 601, being a 12 cylinder, inverted-V (with the crankshaft above the cylinders) design. Both used dual Bosch magnetos firing twin spark plugs for ignition. Fuel injection was powered by a pump supplying up to 90 bar and the oil system used three pumps with a separate 35 litre oil tank. The supercharger was fairly advanced for the era in that it used a barometrically controlled hydraulic clutch (fluid coupling) which allowed the system to automatically compensate for changes in altitude.

One major design difference was the switch from ball bearings to sleeve bearings which, when combined with increasingly poor grades of lubricants, led to serious problems in service, including engine fires; initially, for example, the use of emergency power was forbidden. Although Daimler-Benz redesigned the bearings and added oil slingers and their associated coolers, the RLM considered the DB 605 to be a "sick engine" and the problems had not been fully resolved by the end of the war.[2]

https://en.wikipedia.org/wiki/Jumo_213

When the Jumo 211 entered production in the late 1930s it used an unpressurized liquid cooling system based on an "open cycle". Water was pumped through the engine to keep it cool, but the system operated at atmospheric pressure, or only slightly higher. Since the boiling point of water decreases with altitude (pressure) this meant that the temperature of the cooling water had to be kept quite low to avoid boiling at high altitudes, which in turn meant that the water removed less heat from the engine before flowing into the radiator to cool it.

By contrast, the 1940 Daimler-Benz DB 601E used a pressurized coolant system that ran at the same pressure regardless of altitude, raising the boiling point to about 110°C. This allowed it to use considerably less water for the same cooling effect, which remained the same at all altitudes. Although otherwise similar to the Jumo 210 in most respects, the 601 was smaller and lighter than the 211, and could be run at higher power settings at higher altitudes, making it popular in fighter designs. The 211 was relegated to "secondary" roles in bombers and transports.

Junkers was not happy with this state of affairs, and started their own efforts to produce a pressurized cooling system as early as 1938. Experiments on the 211 proved so successful that it became clear that not only could the engine be built smaller, but could be run at higher power settings without overheating. Additional changes to strengthen the crankshaft and add a fully shrouded supercharger for increased boost resulted in the Jumo 211F model, which delivered 1,340 PS (1,322 hp, 986 kW) at 2,600 RPM, up from 1000 PS at 2,200 RPM in the first version 211A.

But this was only the beginning. After redesigning the engine block to a smaller external size to suit the increased cooling power - while keeping the same 150 mm x 165 mm bore/stroke figures, maintaining the 35 liter displacement of the Jumo 211 series - and then further increasing boost settings on the supercharger, the resulting 213A model was able to deliver 1,750 PS (metric hp) at 3,250 RPM. This made it considerably more powerful than the corresponding DB 601E which provided 1,350 PS, and about the same power as the much larger DB 603. Junkers decided to go after the 603's market, and placed the 213's mounting points and fluid connections in the same locations as the 603, allowing it to be "dropped in" as a replacement, with the exception of the Jumo's standard starboard-side supercharger intake (Daimler-Benz inverted V12 engines always had the supercharger intakes on the port side).

 

[DonL]

THe original intention of the DB 605 was the same as at the Jumo 213, the bored out cylinders were a benefit, but not the original intention.
The intention was to fully integrate the pressurised water cooling. We have also seen a new engine without bored out cylinders.

Take a look at the DB 601E he had a dry weight of 785kg, the bigger DB 605 A only of 756kg.

 

[wiking85]

THe original intention of the DB 605 was the same as at the Jumo 213, the bored out cylinders were a benefit, but not the original intention.
The intention was to fully integrate the pressurised water cooling. We have also seen a new engine without bored out cylinders.

Take a look at the DB 601E he had a dry weight of 785kg, the bigger DB 605 A only of 756kg.

AFAIK the only major difference between the 605 and the 601E was the larger bore of the 605. The cooling system was the same and overall the entire engine block was the same. That and the sleeve bearings instead of ball bearings (was that due to allied bombing of ball bearings?).

The Jumo 213 was significantly different than the 211, being built smaller and stronger, which made it a different engine. The only design similarity between the 213 and 605 was the pressurized cooling system. That's why the 605 had less power than the 213, which was designed to take maximum advantage of the new cooling system, rather than the 605, which just increased its displacement and got lower power than the 213 as a result. The 605 wasn't a full redesign, it was just a bigger bore 601E.

Also I don't think you're right about the 213 being 3 years delayed; in fact I think that at best it would have been ready at the end of 1941 if further 211 refinements were cancelled after the success of the Jumo 211F and Jumo 222 was placed on low priority, with all the resulting engineering resources being placed on the 213 from 1940. At best its cleared for mass production by the end of 1941 and phases in by mid-1942, rather than being cleared in March 1943 and being delayed by Allied bombing until 1944.

Now the DB603 is a different story; had it not been cancelled in 1937 and retained funding, perhaps especially if the DB604 wasn't attempted, then yes I think a 1700PS or better engine could be fully reliable by mid-1941. It would have been excellent for a Ta-152, Do-217, Ju88 development, four propellor He177, and several other aircraft. That was a major mistake of the RLM, which I think came from Udet; considering the original spec resulted from the Wimmer T-amt, which was under Milch's tenure, if we avoid having Wever die and Udet rising to prominence, then the DB603 isn't cancelled and is mass produced from 1941 on. So we have a four propellor He177, a mass produced Do-217, probably and early Ju388 or at least 88S and G, not to mention a Ju188. Probably even a He111 with the DB603. We also probably get more RLM funded Daimler factories to production the DB603...perhaps an early Ostmark type facility? IIRC Ostmark was not planned on until 1941, so with the DB603 being developed and probably ready by 1940-41 having something to produce it in the thousands would be needed in 1938 or so. Right after Austria is annexed it could end up in construction like the Nibelungenwerke, which IIRC was started in 1939. Given the wasted investment in the VW factory at Wolfsburg having a large engine factory started in 1938 ready for 1940-41 makes total sense and in fact more so than building VW in 1939 then never using it to full capacity.

 

[DonL]

AFAIK the only major difference between the 605 and the 601E was the larger bore of the 605. The cooling system was the same and overall the entire engine block was the same. That and the sleeve bearings instead of ball bearings (was that due to allied bombing of ball bearings?).

The Jumo 213 was significantly different than the 211, being built smaller and stronger, which made it a different engine. The only design similarity between the 213 and 605 was the pressurized cooling system. That's why the 605 had less power than the 213, which was designed to take maximum advantage of the new cooling system, rather than the 605, which just increased its displacement and got lower power than the 213 as a result. The 605 wasn't a full redesign, it was just a bigger bore 601E.

Also I don't think you're right about the 213 being 3 years delayed; in fact I think that at best it would have been ready at the end of 1941 if further 211 refinements were cancelled after the success of the Jumo 211F and Jumo 222 was placed on low priority, with all the resulting engineering resources being placed on the 213 from 1940. At best its cleared for mass production by the end of 1941 and phases in by mid-1942, rather than being cleared in March 1943 and being delayed by Allied bombing until 1944.

Now the DB603 is a different story; had it not been cancelled in 1937 and retained funding, perhaps especially if the DB604 wasn't attempted, then yes I think a 1700PS or better engine could be fully reliable by mid-1941. It would have been excellent for a Ta-152, Do-217, Ju88 development, four propellor He177, and several other aircraft. That was a major mistake of the RLM, which I think came from Udet; considering the original spec resulted from the Wimmer T-amt, which was under Milch's tenure, if we avoid having Wever die and Udet rising to prominence, then the DB603 isn't cancelled and is mass produced from 1941 on. So we have a four propellor He177, a mass produced Do-217, probably and early Ju388 or at least 88S and G, not to mention a Ju188. Probably even a He111 with the DB603. We also probably get more RLM funded Daimler factories to production the DB603...perhaps an early Ostmark type facility? IIRC Ostmark was not planned on until 1941, so with the DB603 being developed and probably ready by 1940-41 having something to produce it in the thousands would be needed in 1938 or so. Right after Austria is annexed it could end up in construction like the Nibelungenwerke, which IIRC was started in 1939. Given the wasted investment in the VW factory at Wolfsburg having a large engine factory started in 1938 ready for 1940-41 makes total sense and in fact more so than building VW in 1939 then never using it to full capacity.

I don't fully disagree to your opinion, but there are differences between the Db 601E and and the Db 605.

Why was the RPM of the larger DB 605 (2800 RPM)higher then the DB 601E (2700 RPM)
Also the DB 605 was layout to one handle mode, the DB 601E not and the DB 605A was lighter then the DB 601E.

The DB 603 was mainly cancled through the Bomber B advertisement. I don't want a Bomber B nor a 2000 PS engine advertisement at 1937, to me it is nonsense.
Also the Bomber A only with four engines.

So,
1. DB concentrate on the DB 601 and DB 603 development without DB 604X and DB 606
2 Junkers concentrate on the Jumo 211 and after experience and experiments with pressurized cooling system on the Jumo 213. Further development on the Jumo 211 would be cancled after the F. Also the development of the 004. No Jumo 222 development
3. BMW and Bramo concentrate on development of the BMW 801 from 1936/37 and later on the development of the 003

4. No destroyer development or concept, it will die with the FW 187 in production instead of the Me 110.
5. Also I'm not a fan of this whole experiment with Ju 188 and Ju 388, the Ju 88 did pretty well and the goal is to concentrate on her to make her better as fast bomber, nightfighter and naval- striking aircraft. The Do 217 will do the other jobs.
6. Messerschmitt should only concentrate on the Bf 109 to make her better and the development of the Me 262

 

[parsifal]

Quality is one issue, but my opinion is that German aircraft quality was pretty good throughout the war. They might have done better, but this was not the primary problem for the LW

LWs main problems early in the war were

1) Shortages in production
2) Over-emphasis on whole airframe production, not enough effort on replacement engines
3) Insufficient effort on the pilot replacement programs....as the war progressed German pilots became less and less well trained
4) Linked to the above a shortage of training aircraft

If the luftwaffe could overcome its logistic issues, it would have won the BoB and would not have been bled white in its other campaigns. this was not a function, or a result of poor aircraft designs. it was a function of a generally poor support element. If the numbers had been there, the quality issue would not have mattered

One issue in the technology is the short range of its fighters. Longer range would have been a significant tactical advantage for the Germans.

Another technical improvement for not much outlay would be to convert from drum fed cannon to a belt feed system. 60 round drums for the 20mm cannon is just such an unneccessary constraint on the firepower of the fighter forces

 

[tomo pauk]

The production of the Bf 109 E1 began January 1939 and 1100 were built in the first 8 month of the year 1939.
Also the LW had the Ju 87, He 111, Do 17 and Ju 52 at the beginning of the war (1939) all in decent numbers.

Which other Air Force at 1939 had such aircrafts?
To my opinion you can rate the Ju 87,He 111 and Do 17 at 1939 as very good aircrafts (state of the art) also the Ju 52.

To claim this a/c's were average compare to other Air forces in 1939 is to my opinion wrong

English is not my 1st laguage. I've read the sentence that begins as 'by 1939' as 'at start of 1939'. I'd welcome a clarification.
The Ju-87B in was exceptional aircraft if the opponent does not have a capable defense - it's by no means a perfect aircraft. The Do-17 and He-111 were about as good, or just slightly better than many other similar bombers - Wellington, Hampden, Whitley, SB-2, DB-3, SM-79, Fiat BR.20, CANT Z.1011 and 1007, Martin B-10 and 167, PZL.37. Ju-52 was as good as DC-3 or HP Harrow.

So I will say that German A/C were as capable as what the rest of industrialized world was fielding. It were other factors, listed in above post, that made LW superior from 1939-42 (bar RAF).

 

[Shortround6]

As a quibble the JU 52 was not actually that good as an all-round transport. It might have been pretty good at short, rough field work but it was slow, short ranged, and cramped. Not surprising considering that it was designed in 1930 as a larger version of the 1926 W 33 transport. By the late 30s it was quite possible to haul more payload faster and further on the same amount of power (fuel).