A tool for JSBsim Airfoil Modelling

[IAHM-COL]

Hi @Bomber

So what you are introducing is a x,y definition of the geometry frontier of the transversal section of a wing at the root (535) and tip (549) of the aircraft?

And what you want is the definitions of the geometry along the perpendicular axis, such as a function generates multiple of this definitions? (as predicting the new frontiers in between root and tip?)

Is there a function expected in the transversal across? or would lineal interpolations work perfect here?

[bomber]

linear would work perfectly... to be honest no one but the manufacturers are going to know whether the change is linear or non along the length of the wing... we simply know it starts as one shape and ends as another.

regards

Simon

[bomber]

I think the first issue you might find is that airfoils come with differing numbers of points

[IAHM-COL]

1) I can work with lineal
2) I'll think about the number of points of the geometrical deffinitions

[IAHM-COL]

Important question:

How is JSBsim taking this data like?

Do we introduce the xmls of these wing sections? or do we need to use the wing sections to use another program to predict wing polar diagrams (as in Lift given drag given angle of attack?) and then those polar diagrams are transferred to JSBsim?

[bomber]

these polars are the input to javafoil.... from there we get a series of tables for alpha cl cd and cm

[IAHM-COL]

@Bomber

I might have some idea of how to make the projections of the frontier functions for the airfoils here.
There is one part I am still not convinced is a good way to go for this: javafoil

because this would complicate integration with my idea (working the wing transversal perimeters from python).

I have another question for you:
Have you ever explored airfoilpreppy?
This seems to have some functionality like that you want (including blending multiple airfoils)

The part I am currently not fully clear about is whether airfoilpreppy will be also (like javafoil) be taking the perimeter specifications of the transversal section and calculating the polars (drag/lift) as javafoil does?
Airfoilpreppy has apparently another interesting feature I always wondered -- that of extending wing polar data on a large angle spec (-180/180 or so)

http://wisdem.github.io/AirfoilPreppy/index.html

https://github.com/WISDEM/AirfoilPreppy

[bomber]

There's always pro's and con's...

Javafoil is designed to model airplane airfoils.... it takes in airfoil polars or you can adjust a shape via camber, thickness t/c, and you can use known airfoil manufacturers reference number such as naca to define an airfoil.

It also allows you to add control surfaces, flaps, aileron, elevators, rudder and deflection angles and produces Cl and Cd for that particular shape in that instance.

It's a tool that works for me... I've looked at your suggestion and struggle to understand how to input a known airfoil shape into it.

regards

Simon

[IAHM-COL]

The part I am currently not fully clear about is whether airfoilpreppy will be also (like javafoil) be taking the perimeter specifications of the transversal section and calculating the polars (drag/lift) as javafoil does?

Scratch this

I read the source code, and it just does not.
for this python software, the input is a polar data already. It can't understand anything about the airfoil shapes.

[IAHM-COL]

There's always pro's and con's...

Javafoil is designed to model airplane airfoils.... it takes in airfoil polars or you can adjust a shape via camber, thickness t/c, and you can use known airfoil manufacturers reference number such as naca to define an airfoil.

It also allows you to add control surfaces, flaps, aileron, elevators, rudder and deflection angles and produces Cl and Cd for that particular shape in that instance.

It's a tool that works for me... I've looked at your suggestion and struggle to understand how to input a known airfoil shape into it.

regards

Simon

I was able to input polars into that software. Airfoil shapes, you cant' input them cause it just does not know what to do with such data.
On the ability to extrapolate polars it looks a cool option, thou.

The reason I'm dubious about java airfoil is -- thinking on the long run -- to create our own JSBsim modeller that takes data on one end and packages the sausage of JSBsim on the other end, well, javafoil wouldn't be amiable in terms of being introduced into the pipeline.
Java vs python kind of problem