How to use formulas for a delta wing?

[kevcrl]

Dear Forum,
I'd like to talk about the formulas about aerodynamic calculations.
Let's focus on the lift force.
As you may know, the lift force is computed as

The CL coefficient can be decomposed with a Taylor serie which is

Now, each coefficient can be rewritten in detail as:

As we can see, there is a ratio of of the horizontal surface tail to the wing surface Sh/S
However, how has this parameter to be used in case of a delta wing aircraft with no horizontal tail
Shall we do consider the Sh surface as zero ?
Thanks

 

[Baluncore]

Welcome to PF.

You cannot apply the equations in the same way to balance the lift.
The centre of mass and the centre of lift should remain close. Canards may be used to gain stability of delta wings.
https://en.wikipedia.org/wiki/Delta_wing#Tailless_delta

 

[Lnewqban]

Welcome, @kevcrl !

Delta wings, like any other tailless airplane that needs longitudinal stability, have a built-in tail, which is called reflex.

That works exactly like the horizontal stabilizer of conventional airplanes, providing negative lift to compensate for the natural pitch (nose down) moment that the pressure gradient induces in any airfoil.

Please, see:
https://mh-aerotools.de/airfoils/flywing1.htm

 

[kevcrl]

Very good website thank you very much :)