D.520 Keel

[Vitaly]

Hello everybody.

 

Found some information that D.520 had asymmetric keel.

 

Does anybody have any information about this moment? Is it tue or not?

[RAF4EVER]

Your picture shows a wing plan

[stevehnz]

48 minutes ago, Vitaly said:

Found some information that D.520 had asymmetric keel.

From the diagram you've put up, by keel you mean fin, or tail fin. The idea of an asymmetric fin is not so hard to believe, aviation is littered with offset fins design to counteract the torque effect of engine & prop so using an asymmetric airfoil to do the same job is quite believable.

Steve

[Tbolt]

Yes the Bf 109 also used an asymmetric airfoil for the fin like the D.520. Nice to see a drawing of it though.

 

According to a manual I have, it used the NACA 23012 airfoil "NACA dissymetrique ( asymmetrical ) 23012" for rib 4 - http://airfoiltools.com/airfoil/details?airfoil=naca23012-il 

and the NACA 23008 for rib 1 - https://digital.library.unt.edu/ark:/67531/metadc65038/m1/20/

[Vitaly]

1 hour ago, stevehnz said:

to counteract the torque effect of engine & prop so using an asymmetric airfoil to do the same job

Yes, I know for what such airfoils on fin is used for.

I need information is it true that D.520 really have such tail fin.

[BS_w]

the offset asymetric airfoil was used also on french MS 540 project and on swiss D 3802/3 build.

[Vitaly]

27 minutes ago, Tbolt said:

to a manual I have

Can you share this manual?

[Tbolt]

19 minutes ago, Vitaly said:

Can you share this manual?

 

PM sent.

[dragonlanceHR]

Link to manuals etc.

https://archives.haute-garonne.fr/archive/resultats/transversale/n:3?RECH_S=Dewoitine&type=transversale

[dragonlanceHR]

Don't forget that the nose is bent to the left and that reduction gear housing returns the prop and spinner back to paralel with the centreline.

[BS_w]

2 hours ago, dragonlanceHR said:

Don't forget that the nose is bent to the left and that reduction gear housing returns the prop and spinner back to paralel with the centreline.

 the reduction gear is straight, the prop axis is parallel to centerline engine, so the axis is 1° left

[Sabrejet]

6 hours ago, Vitaly said:

Hello everybody.

 

Found some information that D.520 had asymmetric keel.

 

Does anybody have any information about this moment? Is it true or not?

 

This looks like an original engineering drawing, so I'd say there's no reason to doubt it. From an engineering point of view it also makes sense.