Dewoitine 520 technical details

[greybeard]

Good morning sirs,

I would like to ask some details about D.520:

1. Could the flaps be set in flight at any angle between "raised" and "landing" position?
2. Did have its engine (Hispano-Suiza 12Y45) problems with negative G's?
3. Was its Ratier propeller automatic?

Thank you,
GB

 

[le_steph40]

Some help but in French...
DEWOITINE D.520 - GC III/6 (3/6)
Dewoitine D.520

https://www.bibert.fr/Joseph_Bibert_fichiers/D520_fichiers/1943_07 L_Aerophile 03.jpg

 

[greybeard]

Some help but in French...

Pas de problème.

Unfortunately, notwithstanding the excellent material provided (especially that from l'Aerophile, from a technical point of view), no detailed answers are found about above mentioned questions.

Merci quand même,
GB

 

[greybeard]

Interesting info about my question #2 here.

Unfortunately Waroff doesn't mention his source; in short, this is what he states:

The Solex 56 carburetors of the D.520 powerplant did have their fuel supply channel in the lower part of carburator float chamber. As a consequence, when the aircraft is in negative G the fuel in the float chamber goes up, leaving unfed the channel. He estimates in a few seconds time to engine shut-off, also given that D.520 main fuel tank was not provided of a device for inverted flight. Moreover, the float goes down, leaving open the arrival of gasoline; this latter will make richer the mixture, causing misfires when the aircraft returns to normal flight.

He adds that Bendix had avoided this problem by placing the channel near the center of the float chamber, so that whatever the position of the aircraft or Gs the jet was still fed.

 

[waroff]

1 the flaps could be setting in any position, there is no indicator in the cockpit, but sometime there is three white bar painted on forward edge of LH flap which indicates the angle setted.

2 HS12Y could'nt run during G negative or inverted flight
I 'm wrong when I wrote : " causing misfires when the aircraft returns to normal flight."
it's contrary, with a richer mixture, the engine will get better pick up.(source: Hispano Suiza 12Y engine manual)
richer, yes, but not too rich as I thought previously

3 Ratier electrical variable propeller: the controller had three position switch: Automatic, OFF, Manual
Manual, the pilot choice a rpm by increase or decrease pitch by a 2 momentary positions switch, then return to
OFF: now the propeller is as a fixed pitch propeller.
Automatic: the throttle control a regulator which modify the blade angle setting.
For each position of throttle lever, one regime speed which gives the best output.

Take off, climb, landing : Auto
Cruise: manual, adjust rpm, then OFF
Combat: Auto

 

[greybeard]

WOW!

Definitely, you hit the mark! Exactly what I was seeking, in each and every detail I could wish!

I guess the source for points 1 and 3 is the D.520 flight manual.

UN GRAND MERCI!
greybeard