Sailplane Fuselage

[Mr. chris wedgwood 0]

Hi All,

 

I'm new to Caeses, and learning it is quite daunting, there is so much stuff, and I can't get an overview in my head.

 

What I'm trying to achieve is a generic sailplane fuselage which can then be customised to make any real world sailplane type, and then exported to wavefront so I can then complete the sailplane model using another modelling program. An example is attached.

 

The fuselage needs to have adjustable profiles along its length, and adjustable curvature in the Z axis along the length too. The spigot of the wing root is adjustable in position and size too.

 

What would be the most appropriate techniques in Caeses to use to achieve this?

 

Thanks for any advice.

 

Chris

 

 

 

[Mr. Simon Broenstrup 1]

HI Chris,

 

there are some good tutorials within CAESES that could really help you.

 

I think a suitable way of designing your sailplane would be to create the main body as a sweep surface. Therefore look at the tutorials, Content of General Modeling  >  Parametric Contour and Content of Meta Surface > Sweep Transformation.

 

This way you should be able, to create a parametric profile and create a surface by sweeping it along a patch, which is adjustable in the z-axis. 

 

For the connection of the wing root you could create a small wing (see tutorial First Modeling Steps) and connect it to the main body by using BReps. This is explained further in the tutorial Introduction to BReps. The side rudder can be designed and connected to the body in the same way.

 

I hope this gives you a good idea and brings you on the right track.

 

Cheers,

Simon

[Mr. chris wedgwood 0]

Thanks Simon,

 

I have made decent progress, but i have stalled at getting the wing root fillet.

 

I'm getting error icons in the tree view whenever I try to add the surfaces to the union.

 

I've attached my design. Perhaps you could look at it.

Fuselage.fdbc

[Mr. Simon Broenstrup 1]

Hi Chris,

 

the boolean operation only works with closed BReps, therefore you can use the close-planar holes operation.

 

I also added the a radius at the root.

 

Cheers,

Simon

 

 

Fuselage.fdbc

[Mr. chris wedgwood 0]

You are very kind. Thank you :)

 

Merry Christmas too :)

[Mr. chris wedgwood 0]

Using your updated model above, If i change the wing position in Y using the DXYZ in WingRootLeft and WinRootRight to 0.2 for example, the Bref01 boolean operation doesn't work.

 

.. Can't see why this should happen..

 

[Mr. chris wedgwood 0]

I'm still stuck with this issue if anyone can help..

[Mr. Claus Abt 14]

HI Chris,

The kernel has a problem with the filleting. Creating fillets along intersections with edges (TE) is always a bit tricky. We have an updated kernel in 4.2, soon to be shipped, maybe that can handle the issue better, but there is a principle problem with filleting around sharp edges. Probably someone can show you how to create you a manual fillet, right now I don't have the time.

Cheers

Claus

[Mr. chris wedgwood 0]

Thanks Claus,

 

Whats odd is that the fillets work beautifully until the wing is moved, then there is an error :(

[Mr. chris wedgwood 0]

HI Chris,

The kernel has a problem with the filleting. Creating fillets along intersections with edges (TE) is always a bit tricky. We have an updated kernel in 4.2, soon to be shipped, maybe that can handle the issue better, but there is a principle problem with filleting around sharp edges. Probably someone can show you how to create you a manual fillet, right now I don't have the time.

Cheers

Claus

 

Do you have an idea when the updated kernel 4.2 will be ready?

[Mr. Simon Broenstrup 1]

Hi Chris,

 

I think there are two valid options how you can work around this problem without waiting for the 4.2 update.

 

The first thing which will help you, to have a more stable model is, to change the splitting line of the BRep to the top instead of one of the sides:

 

 

I have done this by changing the start and end angle of your input sections from 0 and 360 to 90 and 450.

 

Another cause of problems is the way your trailing edge is shaped. The sharp edge at the end makes it hard for the fillet feature to find a correct fillet.

 

 

This could be solved by designing a trailing edge with a circular fillet or by creating the fillet between the main part of the plane and the wing manually (but this solution is a bit more complicated)

 

With the circular fillet as the trailing edge it looks much smoother.

 

 

You can find all the cahnges in the attached file.

 

Cheers,

Simon

 

 

Fuselage.fdbc