Post-BoB: workable options for Luftwaffe

[Shortround6]

As for the suggestion earlier in the thread about replacing the Ju 52, I don't know. While the Ju 52 was getting long in the tooth, I'm not sure it was critically deficient in a way that significantly hampered Germany's war efforts. But just for kicks, what would a more modern transport plane look like? Comparing with some widely used contemporary American transport planes we have roughly:

• Ju 52: Empty/gross weights: 5700/9500 kg. Powered by 3 725 hp engines. Carrying 17 troops. Range 1000 km.
• Douglas C-47 (military version of the famous DC-3): Empty/gross weights: 8200/11800 kg. Powered by two 1200 hp engines. Carrying 28 troops. Range 2600 km.
• Curtiss C-46: Empty/gross weights: 13900/20400 kg. Powered by two 2000 hp engines. Carrying 40 troops. Range 5000 km.

I'd suggest something like

• Use two engines. Initially Jumo 211F, thus about 1300 hp each. So just ballparking by the available engine power, could be a slightly bigger plane than the C-47, but definitely closer to that one than the C-46.
• Ditch the tail gunner. If caught by a fighter without escort it's toast anyway, might as well save the weight and drag.
• Modern stressed skin construction. Ideally using wood composites to save on the oh so precious aluminum (somebody said in another thread that Germany actually had quite highly developed technology in this area?).
• We do want more range than the 1000 km of the Ju 52. Something like 2000 km should definitely be achievable?

The Ju 52 was almost as out of date as the Ford tri motor. You would have to deliberately screw up to make a worse transport in 1936 let alone any later.
Figures for a DC3-G2 (R-1820 engine with 930hp for take off), Type certificate Aug 1936.
Empty weight............................................6939kg
useful load.................................................3946kg
Payload (650 US gallons fuel)............1764kg(21 passangers, 3 crew, 320lbs baggage)
Full load......................................................10,886kg
max speed...................................................341kph 6800ft
cruise speed (75%)..................................302kph at 5800ft
Range (75%)...............................................2027km (93 gph)

These may be Douglas advertising brochure figures but you get the idea. Later DC-3s got more powerful engines and higher gross weights (and bit higher empty weights)
The Ju 52 had way too much drag and using three 9 cylinder engines was using up too much engine production.
The Handley Page Harrow offered more performance for less installed power.

 

[Glider]

I have been in a Ju52 at Duxford and its tiny. The idea of trying to get half the stuff that went into a Dakota in a Ju52 is impossible.

 

[z42]

I have been in a Ju52 at Duxford and its tiny. The idea of trying to get half the stuff that went into a Dakota in a Ju52 is impossible.

There are a few remaining airworthy Ju 52's flying tourist flights, and they do have space for 17 passengers. And the one which crashed a few years ago was fully loaded with 17 pax and 3 crew: 2018 Ju-Air Junkers Ju 52 crash - Wikipedia

From googling around a bit, it seems DC-3 had a maximum passenger count of between 28 and 34 depending on seating arrangements.

So depending on what number one uses for comparison, the DC-3 could carry slightly less or exactly twice the number of passengers as the Ju 52.

 

[z42]

The Ju 52 was almost as out of date as the Ford tri motor. You would have to deliberately screw up to make a worse transport in 1936 let alone any later.

The Ju 52 had way too much drag and using three 9 cylinder engines was using up too much engine production.
The Handley Page Harrow offered more performance for less installed power.

Why was the Ju 52 so inefficient wrt engine power? Much of the central engine power being wasted pushing air around the fuselage rather than creating thrust? The corrugated structure creating lots of skin drag?

That being said, I'm not sure about it using too much engine production. The BMW 132 was a very cheap engine (assuming cost correlates somewhat with resources (materials & man hours) to manufacture).

price data for 1941 for some German aircraft types, via Olaf Groehlers GdLK, 1910-1980:
Without engine / with engine, in Reichsmarks (RM)
Bf 109E : 58 000 / 85 970
Bf 110C : 155 800 / 210 140
He 111H : 203 900 / 265 650
Ju 88A : 245 200 / 306 950
Ju 87B : 100 300 / 131 175
Ju 52 : 125 800 / 163 000
Do 17 : 185 500 / 235 00

From here we can calculate the following:

Engine	Cost (RM)	Cost per power (RM/hp)	Engine cost per passenger (RM)
BMW 132	12400	17	2188 (Ju 52)
Jumo 211(F?)	30875	23	2058 [1]

[1] A hypothetical transport with 2 x Jumo 211 carrying 30 troops.

So the main argument for a new transport plane isn't really savings on the engine purchase cost, but you do get more troops per airframe, and probably lower fuel and maintenance costs, and needing less crew per pax.

 

[Shortround6]

From googling around a bit, it seems DC-3 had a maximum passenger count of between 28 and 34 depending on seating arrangements.

So depending on what number one uses for comparison, the DC-3 could carry slightly less or exactly twice the number of passengers as the Ju 52.

You can swap fuel for passengers/cargo. Also be careful of comparing gross weights. The DC-3 started at about 24,000lbs and went to 26,000lbs or more in civilian versions (pre war) while C-47s started at 26,000 and were allowed 31,000lbs overload.

On the question/s of engines.
Make sure you are comparing engine prices and not powerplants. Some Ju 52s used ground adjustable propellers

Mechanics could adjust the pitch setting on the ground and some used controllable pitch or two pitch props

These are not constant speed or feathering propellers. Constant speed props are expensive.


The cost of 9 cylinder radials of about 26-30 liters should not be very different. Assuming 2 valves per cylinder, reduction gears and otherwise similar construction.
Start changing to Liquid cooled V-12s and the costs get very different. Costs of a 14 cylinder radial of equal power to the 9 may be different.

I gave the specs for a 1936 DC-3 using low powered engines to show how far off the Ju-52 was. A 1940 DC-3 with 1100-1200hp engines was going to be different.

As far as the drag goes, yes, the corrugated skinning, while strong, was the same as towing a drag chute behind the plane

Look up the Bristol Bombay and Handley Page Harrow for fixed gear twin engine transports with about the same power (using twin engines) and holding 24 troops.
They could cruise as fast as the Ju-52 would go full speed.

Speed is a consideration in transports. You are looking for fuel burned per pound/mile (or kg/km) and a faster plane with the same fuel burn carrying the same cargo will use less fuel to do the same job.

 

[Glider]

There are a few remaining airworthy Ju 52's flying tourist flights, and they do have space for 17 passengers. And the one which crashed a few years ago was fully loaded with 17 pax and 3 crew: 2018 Ju-Air Junkers Ju 52 crash - Wikipedia

From googling around a bit, it seems DC-3 had a maximum passenger count of between 28 and 34 depending on seating arrangements.

So depending on what number one uses for comparison, the DC-3 could carry slightly less or exactly twice the number of passengers as the Ju 52.

It's the cubic capacity. I would pay good money to see you try and load mules inside a Ju52.

As for the people it could carry, a civilian DC3 is shown below

 

[tomo pauk]

I'd suggest something like

• Use two engines. Initially Jumo 211F, thus about 1300 hp each. So just ballparking by the available engine power, could be a slightly bigger plane than the C-47, but definitely closer to that one than the C-46.
• Ditch the tail gunner. If caught by a fighter without escort it's toast anyway, might as well save the weight and drag.
• Modern stressed skin construction. Ideally using wood composites to save on the oh so precious aluminum (somebody said in another thread that Germany actually had quite highly developed technology in this area?).
• We do want more range than the 1000 km of the Ju 52. Something like 2000 km should definitely be achievable?

There was a thread about 2-engined Ju 52 version here. Granted, the time frame there started much earlier than here, in mid 1930s.
For this thread, I'd again suggest a 2-engined Ju 52, engines in question being 900-1000 HP BMW 132 versions, 1000 HP Bramo 323, or perhaps the war booty G&R 14N (1000-1180 HP). It will not make the Ju 52 better - fuselage was thin body when compared with DC-3 - but it will make it more affordable to the German war economy that was stretched thin even by late 1940. It will be also easier, faster and cheaper to manufacture, maintain and fuel, while also being a cheaper loss once it is lost. Make sure that props are of the good kind, not the laughable units used back in ww2.

I'd also suggest the budget version, 1-engined, dedicated for carrying cargo; sorta more modern looking An-2.

Luftwaffe will need a proper, big transport to suplant the Ju 52. With low content of light alloys used, mainly built from steel, wood and canvas (take the page from British transports and the, kinda sorta, Hurricane) - sized halfway between the Bombay and Gigant, perhaps.

There is no point in making transports and trainers from light alloys, while trying to came out with a wooden combat aircraft, IMO.

 

[tomo pauk]

About the engines, this time Daimler Benz.
At least two things need to happen, IMO: sorting out the valve coating material (be it via better cooperation betweent the engine manufacturers via the RLM, so the BMW solution can be applied, or with higher priority given to the aero engines so they can have a reliable supply of nickel), and application of better 'central' lubrication via the crankshaft. That way, the DB 605A might've been fully rated by, say, winter of 1942/43, and by same token the DB 603A is not such a hot mess in 1943.
Several improvements can be done, independent to one another, some time in 1943: installation of the big S/C on the DB 605 (and on the 603, why wait until 1944 for the AA, AS and E - after all, it's impeller was originally of 280mm dia, while the not-so-good impeller on the BMW 801 was around 330mm - !!), MW 50 system to the fighters, as well as copying the swirl throttle; the 1st two will require that basic engine is debugged, to be on the safe side.

 

[Shortround6]

There was a thread about 2-engined Ju 52 version here. Granted, the time frame there started much earlier than here, in mid 1930s.
For this thread, I'd again suggest a 2-engined Ju 52, engines in question being 900-1000 HP BMW 132 versions, 1000 HP Bramo 323, or perhaps the war booty G&R 14N (1000-1180 HP). It will not make the Ju 52 better - fuselage was thin body when compared with DC-3 - but it will make it more affordable to the German war economy that was stretched thin even by late 1940. It will be also easier, faster and cheaper to manufacture, maintain and fuel, while also being a cheaper loss once it is lost. Make sure that props are of the good kind, not the laughable units used back in ww2.

I'd also suggest the budget version, 1-engined, dedicated for carrying cargo; sorta more modern looking An-2.

Luftwaffe will need a proper, big transport to suplant the Ju 52. With low content of light alloys used, mainly built from steel, wood and canvas (take the page from British transports and the, kinda sorta, Hurricane) - sized halfway between the Bombay and Gigant, perhaps.

There is no point in making transports and trainers from light alloys, while trying to came out with a wooden combat aircraft, IMO.

Ok the fuselage is a little small
But Junkers did know how to build an airplane without sucking up every square meter of garden shed material in the country

They got sucked into the Ju 52 because it was cheap, right up until it wasn't.
They built over 4200 of them up until 1945 and the French and Spanish built more after the war because they had the tooling (cheap and desperate)
Was the cost of 3rd engine worth the cost of better propellers?

The problem with the Ju-52 was cost of the engines and the cost of the fuel/oil per 100km traveled. Other planes could offer 33-50% more distance on the same fuel burned.
When you are operating several thousand aircraft or trying to run months long air lifts fuel burn becomes rather important.
Can't run the flight schools to the needed hours because the fuel hog transports are sucking up the fuel.
Transport flights to North Africa???

Of course the Germans cannot copy an Italian aircraft.

Similar power engines to the Ju-52, a fair amount of wood, 24 passengers, more speed and range.
First flight 1937.

 

[z42]

There was a thread about 2-engined Ju 52 version here. Granted, the time frame there started much earlier than here, in mid 1930s.

Thanks, that was an interesting thread. But yeah, post-BoB it's too late to start designing a new plane from scratch. And to be honest, I'm not sure there's much you can do to improve the Ju 52. Replacing 3 pretty cheap engines with 2 slightly more expensive and powerful ones, while an improvement, wouldn't be a gamechanger in any meaningful way. A bigger improvement would be replacing aluminum in the airframe with steel, wood, and canvas, as you mention, but that would be also mean going back to the drawing board.

It's really about how they're deployed, any realistic improved transport wouldn't drastically change any of the large-scale usage of the Ju 52. A hypothetical "Nazi Dakota" would still be shot down in droves over Crete by AA, and be destroyed on the ground when trying to land on an airfield within range of artillery. Similarly, the Nazi Dakota would still be unable to save Paulus army at Stalingrad or the Afrika Korps, and without air superiority they would still be shot down without mercy in the Palm Sunday Massacre and similar actions.

I'd also suggest the budget version, 1-engined, dedicated for carrying cargo; sorta more modern looking An-2.

I suspect that would, again, be a different plane than the Ju 52, but yes, I can imagine a single engine STOL transport being a useful capability to have. Maybe something like a 10 troop capacity would be realistic given the engines they had.

Luftwaffe will need a proper, big transport to suplant the Ju 52. With low content of light alloys used, mainly built from steel, wood and canvas (take the page from British transports and the, kinda sorta, Hurricane) - sized halfway between the Bombay and Gigant, perhaps.

The Ar 232 could have been useful, had it been deployed in numbers. Replace that weird, heavy and complex undercarriage with one where you put the main gears in sponsons on the side of the hull and you'd pretty much have an early version of a contemporary military transport.

There is no point in making transports and trainers from light alloys, while trying to came out with a wooden combat aircraft, IMO.

Oh, absolutely. This was a big thing they missed, and they should really have done this before the war and before building thousands of Ju 52's.

 

[tomo pauk]

Of course the Germans cannot copy an Italian aircraft.
Similar power engines to the Ju-52, a fair amount of wood, 24 passengers, more speed and range.
First flight 1937.

Think we're on the same page - Luftwaffe needs a much better transport A/C than the Ju 52.

Thanks, that was an interesting thread. But yeah, post-BoB it's too late to start designing a new plane from scratch. And to be honest, I'm not sure there's much you can do to improve the Ju 52. Replacing 3 pretty cheap engines with 2 slightly more expensive and powerful ones, while an improvement, wouldn't be a gamechanger in any meaningful way. A bigger improvement would be replacing aluminum in the airframe with steel, wood, and canvas, as you mention, but that would be also mean going back to the drawing board.

Copy the Italian 3-motors for all I care.
Replacing the engines' part of the Ju 52 is not to improve the Ju 52 itself, but to lessen the burden on German production and maintenance facilities and manpower, while also saving some fuel per same ton x miles flown.

It's really about how they're deployed, any realistic improved transport wouldn't drastically change any of the large-scale usage of the Ju 52. A hypothetical "Nazi Dakota" would still be shot down in droves over Crete by AA, and be destroyed on the ground when trying to land on an airfield within range of artillery. Similarly, the Nazi Dakota would still be unable to save Paulus army at Stalingrad or the Afrika Korps, and without air superiority they would still be shot down without mercy in the Palm Sunday Massacre and similar actions.

I'd suggest not expecting way too much of a new transport A/C

 

[tonycat77]

i'd suggest any transport to use as much steel and wood as possible to free up resources for frontline aircraft.
Also use Jumo-211s, Other threads here showed they still had thousands of them in crates up to 1945.