Sailplane simulations, Part 1 – Modelling

Happy new year everyone!

This is the first part of two part post and like I said in my third post on learning portfolio I got a license key for Star-CCM+ to be used for January. I take good use of it and simulated a full sailplane, which I modeled crudely basing on Glasflügel H-301 Libelle sailplane, which can also be seen in the first image. Libelle is 15-meter class competition glider from the 60s and I found some good schematics of it to make a model. Like the class says it has the wingspan of 15 meters and the original Libelle is a bit over 6 meters in length. I didn’t use the original airfoil for this, but instead I had the data for Nasa-Langley NLF-215 airfoil at hand, so I used that for the wings. For the tail rudder and stabilizers I used the symmetrical NACA0012 airfoil, which I also used in the CFD project course earlier.

Sailplanes-V2-p264
Picture 1: Schematics of the Glasflügel H 301 Libelle, which was used for modelling.

So now we concentrate on the modelling of the sailplane model. For this I used the picture above as a reference since it had all the necessary measurements and a scale to measure other things. And most important of all. It had the different cross-sections of the fuselage. For modelling I used the CAD software most familiar to me; PTC Creo Parametric 3.0, trusty old workhorse.

Picture 2: Definitions of a conic arc section.
Picture 3: Test surfacing the sections.
Picture 4: Decision of modelling only half.

So I started the modelling by creating all the necessary sketches for the fuselage. I had information of the different sections and their dimensions I calculated from the scale in the original schematics. The different cross-sections I made out of conic arcs and the outer fuselage surface was one long spline.  Occasionally I tested that the different sections can be connected to each other with the modelling tools. Also during the modelling I made the decision of only modelling half and later on mirroring it.

Picture 5: Minor problems with the Blend tool.
Picture 6: Finalizing the blending of sections.

After I had the cross-sections ready I blended them together and had some minor problems in between. Well the blending problems got fixed by changing the start vectors so the model doesn’t twist anymore.

Picture 7: Modelling the tail.
Picture 8: Side profile of the near ready model half.
Picutre 9: Some problems with modelling the stabilizer.
Picture 10: The result after mirroring the half. Wings to be attached separately.

Finally when I had the fuselage done I started modelling the tail of the glider. This was a bit trickier part and the connection of the rudder and fuselage had to be done by surface modelling it and after that solidifying the part. When the tail was done I mirrored all the pieces and had a full glider fuselage and tail.

Picture 11: Attaching the wings.
Picture 12: Final model of the sailplane.

With the finalized fuselage model it was time to attach some wings to it in the assembly mode. This was pretty straight forward, just constrain the wing to the proper stub in the fuselage with correct constraints. Voíla we have a full glider with normal wings. I also did the model with blended winglets, but idea is the same just attach some wings to the fuselage.

Picture 13: Teaser of the flow simulations.

Here is also some teasers of the next part with the actual CFD simulations with the sailplane model. I’m doing the simulations with a model with winglets and without winglets just to see do I get any different results. I might also play with the different settings of the simulations just to get more familiar with the software.

Now I’ve been less busy. Spring semester and third period just started with one new course and one more starting later. I’ll be also starting few projects, but don’t worry, I have some posts already under work. I might actually be able to publish something sensible while I do a lot of other stuff too.

Thanks for reading this post. Remember to comment, check the youtube channel occasionally and please share this to your friends.

Pete

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3 Comments Add yours

  1. Ahmad Amar Aiman Bin Zulkafli says:

    hey, is there any video tutorial that i can follow to create the glider like this?

    Liked by 1 person

    1. Petukka says:

      Hey sorry I didn’t see this in August. But no, there isn’t a video tutorial. For me it was a trial and error when doing this, but I’ll take a notice and check if I can make it work at some point.

      Like

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