Re: Ju-252

On Sep 22, 5:24 pm, "Geoffrey Sinclair" <gsinclai...@xxxxxxxxxxxxx>
wrote:
<eunome...@xxxxxxxxxxxx> wrote in message

news:ef04dc2b-7ffa-4b63-8d09-75b3976bc151@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Its arguable that had the Luftwaffe replaced a few hundred outmoded Ju
52 with Ju 252 that the Stalingrade airlift might have succeded in
supply enough food, fuel and amunition.  It certainly could have
succeded in terms of capacity.

My but the jokes keep on coming.

The joke is, as per usual, on yourself.



Firstly ignore the Ju252 V1 first flew in June 1942, and another
3 prototypes had flown by the end of November 1942.  It was not
until the fourth prototype that a loading ramp was fitted.

Getting an aircraft into the air is a matter of priorities.
Transport aircraft were clearly under-emphaised.


The Ju252 useful load 9 tonnes, top speed 273 mph, about twice
the weight of the Ju52.

The Ju52 useful load 4 tonnes, top speed 168 mph.

The cruising speed difference is far more stark. Jumo engines had a
reputation for high fuel efficiency at high power levels that allowed
efficient high speed cruise. Basically the Ju 252 is twice as fast.



So given the easier handling of cargo and deducting the allowance
for crew, defensive armament and fuel, the Ju252 would be worth
around 2.5 to 3 Ju52.  Against that is the need for better airfields
and a more vulnerable target when landing or taking off.

There is no indication that the Ju 252 would require significantly
better airfields. The He 111 did alright as a transport at Stalingrad
though the He 177 did no better due to loadout limitations due to its
inferior landing and takeoff performance.

Certainly the other competitor to the Ju 252/Ju 352 was the Arado Ar
232 and Ar 232B.

This aircfat for instance had a takeoff run of only 200m and due to it
22 'millipede' feet could not
only 'squat' to lower itself into a better loading position but
traverse soggy soggy ground and
ditches as much as 1.5m.


The pocket needed 650 tonnes of supplies a day according to 6th
Army, at say 6 tons per Ju352 (do not forget the packaging of the
supplies,

The Ju 252 trapoklappe loading ramp would allow relatively efficient
bulk packing for some goods eg ammunition cases whch already come in
boxes. Jerry cans of water or fuel and Fuel drums add maybe 10%.
Pumpernickel Bread in paper (german k-rations), Caned food very
little.

I would propose that packing allowances had already been made.

they have weight, one of the US Army's main efforts in
WWII was creating appropriate packaging, not to mention the
great difficulties of ending up full and down, that is all space used
just as the weight limit is hit, or vice versa), means around 120
sorties per day, allowing for interceptions and mechanical failure
type aborts.

The Ju 252 had far greater cruise speeds; over 240mph that would have
allowed it to complete its transit in less than 50% of the time of a
Ju 52 which cruised at less than 120mph. Due to the 'trapoklappe'
rear loading lamps even the turnarounds are likely to have been twice
as fast due to the level floor and ground level access and so we have
the Ju 252 not only carrrying 2.5 times the Ju 52 cargo but doing
twice as many trips: 5 times as much cargo. The aircraft had also
been designed for delivery of large para retarded loads through the
rear ramp.

The Ju 252 was a class act, superior in many ways to the C46 and C54
the later of which wasn't even pressurised. It could even have
carried two tons of cargo from Germany to New York with reserves. In
many ways it was a 'strategic' transport.

Maximum speed was 272 mph (438 km/h) with a maximum cruising speed of
242 mph (390 km/h). The service ceiling was 20,670 ft (6300 m). Range
of 2,473 miles (3980 km) with maximum payload (7 tons or 9 tons if
overloaded on a good airfield). With only 4,410 lbs (2000 kg) of
payload range increased to 4,100 miles (6600 km). Empty the aircraft
weighed 28,880 lbs (13100 kg), with a normal load out it weighed
49,560 lbs (22480 kg) and with maximum overload it weighed 52,910 lbs
(24000 kg). It had a span of 111 ft 10 in (34.09 m); length 82 ft 4 in
(25.10 m); height 18 ft 10 1/4 in (5.75 m) and a wing area of 1,320 sq
ft (122.3 sq m).



Of course it was winter of the steppe, the number of good flying
days and the hours of daylight means there would need to be a
surge on good weather days.  Plus of course the airfields in the
pocket would need to cope with the bigger aircraft.

500 tons was considered the subsistence level.

650 tons minimum, 9 tons of cargo per aircraft means 74 sorties are
required. If each aircraft did two sorties per day then 37 aircraft
are required. Assuming a distance of 1000/km or 600miles from the
frontline a round trip would require 5 hours or 6 assuming loading and
unloading. So one trip arriving in the early morning that returned
with more cargo 5.5 hours latter.

Such was the performance of this aircraft that 74 of them could have
supplied Stalingrad all the way from Berlin and flown all the way back
with a small cargo of wounded and other evacuees without even
refueling.

Allowing for damage, repairs, losses and some replacements from new
production 100 would have sufficed. Of course some other types such
as the Ju 52 would have been also available.

It would have dramatically improved Rommels supply situation in Nth
Africa.




It was of course the bad weather and the lack of airfields in the
pocket that destroyed airlift capacity, with help from the Red
Air Force and AA gunners.  The Germans had 300 aircraft present
designated as transports in December.  None of them had the
capacity of the Ju252 but they had a much bigger lift than was
delivered to the pocket.

The problem was that many were spending time refueling or acting as
relays.

The problem was that only 40% of the aircraft were in a flyable
condition becuase the crews and aircraft had been exhausted.

The reason they had been exhausted is becuase the crappy performance
in temrs of range, speed, load of the Ju 52 meant inefficiency. Its
good points being ease of serviceabillity and STOL like behaviour that
was nvertheless inferior to the Ar 232.

Those bombers pressed into servive as tansports were also inefficient
as cargo aircraft.

Furthermore the poor range of the Ju 52 meant it needed its own fuel
supply trail which itself caused wastage of resources and double
handling.



.

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