D.520, several modelisation and models issue

*I don’t understand how to do historical report on this forum, so I am here.

Hello, I am currently looking at the “archives de Haute-Garonne” which uploaded all the construction plan for the D.520.
Here are some problem I saw in the game.

The water radiator is too big, and he is too efficient.

We have several witness claiming the engine was overheating during fast climb (220 km/h IAS), in game this is not the case and only a 5% opening is enough to deal with heat. So this is probably why:
The modelised water radiator is way too big in the model.

Here is the current one in game: massive radiator under the wing

Here is the construction plan for this radiator:
Source, page 103
Here is an illustration of how it should be (part 21)

In game we should see something like this:

BTW, the frontal water tank is too big too.

aileron articulation are not accurate (btw, just modelisation if you rework the 3D model)

First little modelisation problem, how the flaps are fixed (this is a really minor 3D model problem but now you know)

How it should be:

source p.21

There is no command to change oil radiator opening, but there is in game

In game, we can both change Water radiator opening, and oil radiator.
The real plane have only one command: it is for water control.

Water command IRL:

Water command in game:

Oil radiator IRL:


In game the oil radiator is maybe a bit small, but this is pretty accurate if we forgive the oil command
In the pilot flight manual, we read there is a command for water radiator opening, but no mention of oil radiator control.

There should be only 2 flaps positions.

Flaps can only be on position open or close. There are no combat and take off position.

We see on this document the command tube can only take 2 position, 0 or 80°
(and there is only one position for the command in the cockpit)

How does it works? check the plans:
Flaps in

Flaps out

Any position between those 2 position is not stable.
Here is an image where you see the real flaps position. It support my photomontage with the flaps having a little slide to the rear, and this is not the case in the game!

There is an automatique pitch, but not in game

Simple problem: the propeller Ratier and Chauvière have an auto pitch, we can see it in the cockpit: the pilot can switch between automatique, neutral (when broken) and manual.

Fuel repartition in game is broken.

IRL, when using the D.520 for mission the pilot were cleaning the wing’s tanks and only used the central one.
In game, the fuel is in the wing’s tip which are not protected, leading to a fuel fire each time a lost bullet hit the wings… Even with minimum fuel (39 minutes !!!), the central tank is not full in favor of the wings tanks.
BTW, in pilots notes: “Toutes les évolutions acrobatiques doivent être effectuées réservoirs d�ailes vides, trains et volets rentrés.”
'All aerobatics have to be performed with empty wing’s tanks, gears and flaps up."
Source (not a perfect one, but so old, accurate and lost that it is made with the real notes which are not on the internet)

Wrong animation on the stick

When firing with the 7.5 mm, the red button goes down. This is a wrong interpretation of the commands. The red button is th “bouton poussoir” for breaks! For firing the pilot is using the lever behind the stick!
To select if he shoot with 7.5 or 20mm, it is with the control pannel behind the stick.


In the manuel, the lever is named “doigt de tir”

Gaz command is not moving in the good way

When increasing throttle, the pilot is pulling the manette. If he want to decrease he push it.
This particuliarity of the plane was well known. But I can’t give perfect sources.
We can read here: " Tout à coup, je m’apperçus que le peloton me distançait. La manette des gaz était pourtant tirée à fond."
The translation: “Suddenly, I noticed that the peloton was distancing me. The throttle was nevertheless pulled all the way.”
from here

And here: " je tire la manette des gaz jusqu’à plein gaz."
Meaning “I pull the throttle to full power.”
from here

Compas doesn't work

Simple, since years, D.520’s compas doesn’t move. Bug can be reproduced in test flight.

That is all. I can’t check the wings profils but if needed for the near futur D.520’s 3D model rework (lol) all the ressources and details are in the archive: Avion D.520s. AD31 - Archives départementales de la Haute-Garonne


For Radiator → gaijin mostly modeled all Radiator with the air channel, this was tru for a long time.

They also made it for jet engine at a time (FJ-4 as exemple) then came back on it, when players complainned of being to easily shot down.

D.520 radiators is still bigger than other prop’s radiators. If you look at Spitfire or 109 you see the difference.

So this is not an argument to keep this huge radiator taking all the shrapnel from the battlefield.

I’m just saying why it is like that,… not that you’re wrong or anything similar,…

No problem, I am just saying why it is bad in general. Sorry if it was rought

“Radiator being too efficient” that’s not bad to be able to full WEP your engine (but i always overheated when used WEP in prolonged ways[2mins+])


In order to make a historical report, please go here: Gaijin.net // Issues

Please note it should be one issue per report. Not bundled into one.

Include a title and summary of your issue in the fields provided:

Then please set the following:

From there, you can add historical files and the comparison game screenshots here:

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Going deep into the D.520’s cooling is a bit ackward, because Wt generalise the same mechanism to all plane.

IRL, the plane is overheatinf at 125°. Over this tempereature, the engine simply dies.
In Wt, depending on the map, you may sometime heat over 125°, or sometimes over 121°… it is weird, but let’s consider 125 is our maximum as IRL.
For oil maximum temperature should be 100°C, but anyway, Wt is not a simulator so let’s play with Wt’s rules.

With fixed 10 % oil radiator because whe sould not open it, those are my results in a 220 km/h IAS climb with WEP on the test map:
0% water: overheat (blinking red at 122°C) after 2000m with 1:45 min climb (comment: this temperature decrease after 3000m and I am damaged at 121°C at 3500m)
10% water: never overheat, never exceed 115°C

10% water is visually like closed radiator.
To get something like the radiators we can see on photography, assuming the photos as been took at low speed because most of them have open canopy, we should fly with at least 60% radiator. (and 10% oil)
This configuration, with maximum manifold pressure and low pitch (to keep low speed but with WEP for the trial) doesn’t make us exceed 100°C

If we consider we are in an airfield circuit or on low speed maneuver (let’s say 200 km/h) with the appropriate pitch, we can keep both radiator closed (!) without going over 110°C. So why should pilot open radiators like this if it is not necessary?

Speaking about temperature in game is not easy, there are not a lot of data and good luck to find the real one. This is only feeling, and real feeling for pilots was overheating problem while climbing (not in cruise).
As a comparison, if you look at IL2 CoD’s D.520, the cooling is way more credible (maybe it is even a too poor cooling).
I don’t think there are ways to compare reality and Wt because the temperature doesn’t have the same effect and D.520 was modelised with oil management so I don’t know what value I should use for my test.

IRL exemple

(and many more)

So the old Historical issues system goes in bug-report? I am right?
I am not sure where my different point should go. As exemple, my fuel issue is not a “bug”, it is Gaijin choice but it makes no sens. It should be a suggestion for better fuel management or a “bug” for inaccuracy?

Is fuel even distributed between fuel tanks in an order or no? Let’s say if we take 50% fuel load then are all tanks half full? @Smin1080p

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Bonsoir Camarade @pyromaniac1689

Big thanks for the documentation about the D.520 !
Did you have any feedback from Gaijin ? Is there a ticket that I can support.

I also note that the speedometer does not work at all (the needles stay stucked on zero). I open a ticket on the Gaijin support here : Gaijin.net // Issues

See you in the sky !