Looking for a technical term

[Nyal Williams[_2_]]

Is there a term for the difference between the angle of incidence of the
wing and the angle of incidence of the tailplane? I have heard/read
decalage used this way; however, wikipedia says decalage means the
difference between the angles of incidence between the two wings of a
bi-plane. (Thinking of that makes me think that extending Fowler flaps
turns the aircraft into a bi-plane).

Is there a separate term? Is this usage correct (Is Wikipedia just
incomplete?)?

[Mike Bamberg]

On Sep 28, 11:15*am, Nyal Williams > wrote:
> Is there a term for the difference between the angle of incidence of the
> wing and the angle of incidence of the tailplane? *I have heard/read
> decalage used this way; however, wikipedia says decalage means the
> difference between the angles of incidence between the two wings of a
> bi-plane. *(Thinking of that makes me think that extending Fowler flaps
> turns the aircraft into a bi-plane). *
>
> Is there a separate term? *Is this usage correct (Is Wikipedia just
> incomplete?)?

Normally the angle of incidence is relative to a datum reference on
the fuselage. The wing is usually described as a positive angle (if
the leading edge is raised above the trailing edge of the chord) and
the tailplane is a negative (if the leading edge is down relative to
the trailing edge).

The angle of decalage is usually described as the relative angle
between the chord line of the wing and the chordline of the tailplane
(or other surface). No reference to the fuselage datum is made.

Mike

[[email protected][_2_]]

On Sep 28, 11:15*am, Nyal Williams > wrote:
> Is there a term for the difference between the angle of incidence of the
> wing and the angle of incidence of the tailplane? *I have heard/read
> decalage used this way; however, wikipedia says decalage means the
> difference between the angles of incidence between the two wings of a
> bi-plane. *(Thinking of that makes me think that extending Fowler flaps
> turns the aircraft into a bi-plane). *
>
> Is there a separate term? *Is this usage correct (Is Wikipedia just
> incomplete?)?

Looks like Wikipedia is incomplete. Decalage between wing and tail is
used to generate pitch stability.

Take a look at http://www.av8n.com/how/htm/aoastab.html, it has a good
explanation.

Kirk

[Nyal Williams[_2_]]

Thanks for the reference. I just wanted to be sure of the usage. I agreed
with everything in the explanation except the pronunciation of the word,
but that is hard to do without offering a full graduate course in
phonetics.

I'm happy to have the article to support my arguments about turning
flight.


At 18:39 28 September 2009, wrote:
>On Sep 28, 11:15=A0am, Nyal Williams wrote:
>> Is there a term for the difference between the angle of incidence of
the
>> wing and the angle of incidence of the tailplane? =A0I have heard/read
>> decalage used this way; however, wikipedia says decalage means the
>> difference between the angles of incidence between the two wings of a
>> bi-plane. =A0(Thinking of that makes me think that extending Fowler
>flaps
>> turns the aircraft into a bi-plane). =A0
>>
>> Is there a separate term? =A0Is this usage correct (Is Wikipedia just
>> incomplete?)?
>
>Looks like Wikipedia is incomplete. Decalage between wing and tail is
>used to generate pitch stability.
>
>Take a look at http://www.av8n.com/how/htm/aoastab.html, it has a good
>explanation.
>
>Kirk
>

[Ralph Jones[_2_]]

On 28 Sep 2009 18:15:03 GMT, Nyal Williams >
wrote:

>Is there a term for the difference between the angle of incidence of the
>wing and the angle of incidence of the tailplane? I have heard/read
>decalage used this way; however, wikipedia says decalage means the
>difference between the angles of incidence between the two wings of a
>bi-plane. (Thinking of that makes me think that extending Fowler flaps
>turns the aircraft into a bi-plane).
>
>Is there a separate term? Is this usage correct (Is Wikipedia just
>incomplete?)?

Yes, Wikipedia is incomplete. Decalage can refer to a difference in
incidence angle between any two aerodynamic surfaces.

rj

[Mark Jardini]

I have also heard it referred to as "longitudinal dihedral".

[Nyal Williams[_2_]]

That's funny!

At 05:46 29 September 2009, Mark Jardini wrote:
>I have also heard it referred to as "longitudinal dihedral".
>