Unraveling the JU52/3m data

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DarkHorse2
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Unraveling the JU52/3m data

Post by DarkHorse2 »

I admit I have been looking at this for a while and still find it confusing and contradictory how much misinformation exists regarding the Ju52/3m performance data.

On one hand, you have WiTE2's data for the Ju52/3m:
Max Speed: 180mph
Cruise Speed: 134mph
Endurance: 230mins (3.83 hrs)
--
Fuel Capacity: 2315lbs (which equates to 369 US gal or 1400 L)
Range: 524 miles (one-way)
Radius (combat radius): 170 miles (17 hexes)
--
Max Fuel Capacity (auxiliary fuel tanks): 3969lbs (which equates to 634 US gal or 2400 L)
Max Range: 863 miles (one-way)
Max Radius (combat radius): 280 miles (28 hexes)
and then try to reconcile with historical accounts, such as -
Perhaps most importantly, Student used his position as the commander of the 7th Flieger division to assign Junkers Ju-52 transport aircraft and crews to train and support his newly formed division. This three-engine monoplane was originally designed as a commercial airline transport; pressed into Luftwaffe service, it could haul twenty passengers, thirteen parachute troops or two tons of cargo over 800 miles as the primary German airlift aircraft for the coming war.
or -
Circling overhead to wait for the dust to settle, the Ju-52s ran low on fuel; some circled for two hours, making their first sortie some six hours long after the initial delays in the morning, the flight to the first drops, and the return trip.
or -
A military version of Eisen Annie, designated the Ju-52/3mg3e was ready for service in 1934. While a version designated the Ju-52/3m Sa3 was already operating for the Reichswehr in the role of personnel transport, cargo carrier, and pilot trainer, the g3e was intended as an interim bomber before more sophisticated bombers were available in 1936. The military version was powered by three 660hp BMW 132A radial engines and armed with dorsal and ventral 7.92 MG 15 machine guns, the latter of which was affixed to the aircraft’s underside with a retractable dustbin attachment. When fully loaded, whether with troops or supplies, the aircraft had a top speed of 171 miles per hour and a cruising speed of about 120 miles per hour. The Ju-52/3m’s round-trip range carrying a 1,984-pound load was 720 miles. This range increased to 900 miles with a lighter load (992 pounds) or decreased to 450 miles with a heavier load (3,306 pounds).
:?: :?: :?:

So, how do we go from 800 miles (or 900, 720 or even 450 miles) to WiTE2's 280 miles?

1. There is quite a bit of performance variance in Ju-52/3m's sub-versions, as shown here:
Ju523m_Performance.JPG
Ju523m_Performance.JPG (109.7 KiB) Viewed 1449 times

2. WiTE2 never fully discloses what specific Ju-52/3m model their data is derived from.

(Given that the Ju52/3mg7e entered production in 1940 and has been documented to have been in use for the 1941 airborne invasion of Crete, I am inclined to believe this would be the most appropriate version...)
3. The Ju52/3m afforded a wide range of load options. Despite that only 2 are shown below (or used in WiTE2), there was further variance in Ju52/3m's load out configurations.
The ubiquitous Junkers JU-52/3m g7e Luftwaffe transport of 1941....had a "standard" fuel load to carry it 540 miles carrying a "load" of 4,050 lbs. The fuel was carried in six interlinked "tanks" per wing, laid out along the centre of the main wingspar, a total of twelve fuel "cells". The fuel load to carry it 540 miles ONLY filled up the tankage by about two-thirds...

However - it could top off its fuel tanks right to the very top....and carry enough fuel for 810 miles' range.
Ju523mg7e_Ladeplan.jpg
Ju523mg7e_Ladeplan.jpg (758.85 KiB) Viewed 1449 times

4. What range? One-way? Two-way? Max range? Combat range? Combat radius?

Way too much for me to go into, but the following will be helpful.
see https://en.wikipedia.org/wiki/Range_(aeronautics)

In general, the best I can tell, WiTE2 computes this as:

Range (one-way) = Endurance(minutes) * Cruise Speed(mph) * (1 hr/60 minutes).
Radius (combat radius) = SOME_FACTOR * Range (not disclosed)

Alternative Method 1:
A rough formula for calculating a plane's radius of action is: Range / 2 * .80 = Radius of Action
see - page 43, https://bootcampmilitaryfitnessinstitut ... d-1942.pdf

Alternative Method 2:
The rule of thumb is that the radius of action is one-third the distance an aircraft can fly in a straight line on a full load of fuel. In military aviation, this assumes a trip out and back, plus one-third of fuel for combat operations.
Regarding WiTE2 and the Ju52/3m, it appears as follows:
Range: 524 miles
Radius:170 miles (in this instance, WiTE2 Radius is 32% of total range) :o
Radius: 209 miles (using Range / 2 * .80) method
Radius: 174 miles (using Range / 3) method
Range (w Tanks): 863 miles
Radius (w Tanks): 280 miles (again, WiTE2 Radius is 32% of total range)
Radius (w Tanks) : 345 miles (using Range / 2 * .80) method
Radius (w Tanks) : 287 miles (using Range /3) method

Presuming WiTE2 base range data is correct for the Ju52/3m (which I highly doubt - requires a correct value for Ju52/3m's Endurance (which further requires correct fuel capacity and consumption rates), another story... sigh...), but to use the exact same formula for the Ju52/3m's Radius as the one WiTE2 uses for fighter escort missions, bomber ground support missions, ... , may possibly be appropriate for Air-Drop missions (which is a round-trip mission), it is not appropriate for Airbase-to-Airbase air transport supply missions.

As it is, the Ju52/3m's air transport supply ranges are getting whacked with the nerf-bat twice.
* First by using incorrect Range values(derived from incorrect Ju52/3m Endurance values);
* and once more for further restricting the Ju52/3m effective mission range to just 32% of the under-reported in-game Ju52/3m Ranges for missions that should be using something closer to 80%.

(I would argue that the Ju52/3m effective ranges are even more important than their cargo capacity and would gladly sacrifice some cargo if given more range - which historically, was afforded; however, WiTE2 does not provide that feature either.)

:(

ouch, ouch
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Wiedrock
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Re: Unraveling the JU52/3m data

Post by Wiedrock »

DarkHorse2 wrote: Wed Feb 08, 2023 5:37 pm
2. WiTE2 never fully discloses what specific Ju-52/3m model their data is derived from.

(Given that the Ju52/3mg7e entered production in 1940 and has been documented to have been in use for the 1941 airborne invasion of Crete, I am inclined to believe this would be the most appropriate version...)
A list of (I guess all) JU's produced with the Versions and users. Maybe this helps to determine which version would be the most appropriate one to use in game.
https://ju52archiv.de/Ju52.pdf
Jango32
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Re: Unraveling the JU52/3m data

Post by Jango32 »

They still happily crash into the ground when doing an airbase level 3 (Smolensk) to airbase level 2 (Vyazma) supply run in perfect weather with perfect supplies, fuel and 0 fatigue. Once you clear the Baltic countries (turn 4 or so) they rapidly become useless. Increasing the range, whether it is warranted or not, won't change much in the grand scheme of things.
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Joel Billings
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Re: Unraveling the JU52/3m data

Post by Joel Billings »

I can't speak to the data of the aircraft, as I leave that to Dennis. As for the range, yes, the fact that transports can only fly 33% (combat range) is low, and we agreed last summer to try to increase it to 45% for delivers to non-isolated/non-beachhead hexes. I've bumped that up, so assuming it can be done safely and without too much difficulty, we're going to try to have that done in the next update. As for the op losses, they are intended to be bad in bad weather and at night. I just flew some missions that were in totally clear weather and had less than 1% op losses. Are you flying from larger airfields, especially when the weather is not clear? Maybe the bug just fixed in 1.02.51 where it was calculating the weather incorrectly was having an impact on transport missions. If you have saves you can give me where I can run air transport missions and see the high losses you're talking about, that would help. If you put a save up, tell me what units are flying, from what depot, and to what hex, and I'll try to recreate what you're seeing.
All understanding comes after the fact.
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AlbertN
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Re: Unraveling the JU52/3m data

Post by AlbertN »

The problem is quite articulated I feel.

The Air Transport present system has a relatively wonky air-to-air combat that does not provide results in line with other type of air combat situations.

Then besides that the Air Transport proper have both the OPs losses and the 'damaged' per flight.

OPs losses in fair weather and airfield to airfield in tiny or even just rainy weather should be well below 1%. Think that even heads of state took these airplanes, or general. And while crashes happened they were remote and in general in bad weather condition.
Without enemy interference flights should be virtually safe from the full OPs losses.
There is the 'damage' business, which I take it as a wear and tear of the equipment (Each subsequent flight will have less air transports at hand because somehow they get damaged). I am not even sure that is correct from the logical viewpoint but that's how it is.

It's like atm - without enemy interference - each Ju52 can pratically fly 2 twice a week averagely.

Now IF the airplanes fly in Blizzard, and land in Tier 1 airstrips then yes some OPs losses can well happen, I agree to that perfectly. But in general without forms of enemy action even that should be limited.
The 'real' losses were at Stalingrad when in the midst of winter the LW had to fly through the enemy ring of AA, enemy fighters and the arriving airstrips were under enemy bombing capability and then even shelling from guns.

The thing is that in most cases players avoid something as sizeable as Stalingrad, thus in WITE2 there will virtually never be historical Air Transport losses due to historical reasons (assuming players start a regular campaign and not a StB scenario) because players will be either way more careful in their own play, or pockets will be in general liquidated way faster.
OP losses and damaged planes should be fine tuned not on 'historical numbers' (as history is not replicated in each and every step but players play their own thing) but should be more or less appropriately modelled in terms of losses -without- enemy action. Enemy action has own formulas then due to AA where interested and air interception.
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Joel Billings
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Re: Unraveling the JU52/3m data

Post by Joel Billings »

Using Stalingrad to Berlin, or the RAR scenario, you can see a Stalingrad pocket and see what losses are like in those cases. I understand you believe that the loss rate it too high. Without saves, we can't see how/why (what conditions) you are getting the high losses, so we don't know what to change.
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Nikel
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Re: Unraveling the JU52/3m data

Post by Nikel »

Contrary to Stalingrad, Demyansk pocket airlift was considered a success, another league of course.

Image

There is a very interesting digitised document in the Bundesarchiv.

I understand the following for this particular Kampfgruppe:

Sorties 5200

Hours flown 12430

Kms flown 2135000

Tons of supplies transported 9900

Aircraft losses 14 Ju-52


42 aircrafts at Kowno and 14 losses for the operation looks very high, but this means a 0,27% loss per sortie, so in fact it is very low.

2,39 h and 410 kms per sortie, so 172 kms/h. Several supply bases are cited.

1,9 Tons of cargo per sortie.

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Denniss
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Re: Unraveling the JU52/3m data

Post by Denniss »

Ideally we'd have an air transport system permitting the use of 85-90% of the aircraft's range if a direct transport from airbase to airbase is possible (without enemy hexes nearby or on flight path) and the target airbase has sufficient fuel on hand to refuel all aircraft.
This may not be possible in the current air system though.
Denniss
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Re: Unraveling the JU52/3m data

Post by Denniss »

The unarmed Ju 52/3m G7e with 11.000 kg max weight had a load capacity of 3350 kg (fuel + cargo), the armed version (two MGs) of 3220 kg.
Maximum fuel load of 2400 liters is stated as 1850kg (which is .77 kg per liter, ingame we use .75 kg per liter for standard aviation fuel)
Our Ju 52 is currently modelled for 3250 kg load of which 1050 kg is fuel and 2200 kg is cargo.
The aux fuel tank option brings it back to full internal fuel
DarkHorse2
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Re: Unraveling the JU52/3m data

Post by DarkHorse2 »

Denniss wrote: Thu Feb 09, 2023 2:47 pm Ideally we'd have an air transport system permitting the use of 85-90% of the aircraft's range if a direct transport from airbase to airbase is possible (without enemy hexes nearby or on flight path) and the target airbase has sufficient fuel on hand to refuel all aircraft.
This may not be possible in the current air system though.
Sorry for the late response....

Yes, that would be closer toa reasonable operating range for Airbase-to-Airbase supply missions.

One big problem that exists is this universal Radius formula that is being used for nearly all missions.

For some missions, it may be appropriate. However for supply missions it is overly restrictive.

Rather than take max range and multiple it by (0.35 - or something similar) to calculate combat radius, they actually used a calculation based off of the mission profile for the aircraft.

These would factor in various segment flight times, according to its mission.

Assuming the WiTE2 Ju52 data is correct for its Max Range (currently 810 miles?), which I have reasons to doubt, to further limit it's operational radius from 405 miles to 280 miles is excessively restrictive and arbitrary.

At the least, I would like to see the Ju52/3m data updated to use that for the Ju52/3mg7e (and the associated BMW 132T-2 engines).
MissionProfiles.JPG
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DarkHorse2
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Re: Unraveling the JU52/3m data

Post by DarkHorse2 »

@Nikel

Just getting around to catching up on thread.

Very interesting document....
DarkHorse2
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Re: Unraveling the JU52/3m data

Post by DarkHorse2 »

Denniss wrote: Thu Feb 09, 2023 6:40 pm The unarmed Ju 52/3m G7e with 11.000 kg max weight had a load capacity of 3350 kg (fuel + cargo), the armed version (two MGs) of 3220 kg.
Maximum fuel load of 2400 liters is stated as 1850kg (which is .77 kg per liter, ingame we use .75 kg per liter for standard aviation fuel)
Our Ju 52 is currently modelled for 3250 kg load of which 1050 kg is fuel and 2200 kg is cargo.
The aux fuel tank option brings it back to full internal fuel
Regarding WiTE2's current data:
I actually believe that WiTE2 is using 1800kg for fuel (not 1850kg)

Working backwards from WiTE2's current Ju52/3m Sortie fuel value of 3969 lbs. (3969 lbs = 1800 kg)
1850kg of Fuel using 0.75 kg / L = 2466 L (not 2400 L); however
1800kg of Fuel using 0.75 kg / L = 2400 L
The Max Fuel allowed for the Ju52/3m should be increased to (at least) 1850kg (2466 L) (4078 lbs)

WiTE2 Ju52/3m Cruise Speed: 134 mph
Arbitrary data value (not derived).
I highly suspect current data is using BMW 132A engine data, as it appears low for the BMW 132T-2 (830hp) engines.

257 km/hr - https://www.tracesofwar.nl/articles/245 ... -52-3m.htm
157 mph (253 km/hr) at 4,595 ft (1,400 m) - https://www.ww2-weapons.com/ju-523m/
250 km/hr - http://www.aeroram.narod.ru/win/samolet/ju-52.htm
157 mph - https://hubpages.com/education/The-Smithsonians-Ju-52s

WiTE2 Ju52/3m Endurance: 235m + 141m (aux tanks) = 376m (6.266 hrs)
Arbitrary data value (not derived) and will need to be updated to account for the updated Max Fuel values (above).

WiTE Ju52/3m Max Load: 4853 lbs (2200 kg)
MOTW generally being a design max weight that the aircraft has been stressed to on the drawing board and flight tested at, often exceeded in wartime conditions... (from all accounts, the Ju52 were commonly overloaded) If WiTE2 is going to use historical OPS losses for the Ju52, it should also afford the overloaded weight capacities flown.
BMW 132 T or Z engines each with 725 hp (533 kW) take-off power, normal take-off weight: 11,000 kg maximum take-off weight: 12,500 kg with special permission, series production from mid-1941
(note - the BMW 132 T-2's afforded 830 hp take-off power)
https://www.fliegerweb.com/de/lexicon/G ... +Ju+52-754

Given a MTOW of 12,500kg, this would easily accommodate 1850 kg of fuel + 2590 kg (5709 lbs) of cargo AND still only require a MTOW of 12,252kg.
Denniss
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Re: Unraveling the JU52/3m data

Post by Denniss »

132T has same engine power as 132A, this is 725 max and only possible for one minute at low alt.
BTW all transport aircraft are similarly affected by the reduced range
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