A complete report on the aerodynamic and strength design of an ul aircraft

Happy new year! Best wishes for 2019!
I start a more detailed technical report. Not only because I want to advertise my design but additionally because (I think) some people want to design and built their own planes. So this technical report (maybe) will be useful.
I like planes since I was a child and I want to build my own plane. My studies at university (i am a civil engineer) was useful throughout the design. It required to study structural analysis and it is highly recommended study finite element analysis for someone who wants to design a plane. You can design a plane with classic structural analysis and hand calculations but you need a finite element analysis software if you want to solve a sandwich structure and/or to run a flutter analysis. Theoretically, you can solve anything by hand calculations but you will spend a lot of time. It is not possible in the real world.
Also before you choose the software you have to choose structure materials. Because some software isn't solving laminate materials (if you want to build a composite aircraft).
There are a lot of software out there which you can use. From free open source to very expensive commercial like ansys.
I go with open source and low-cost commercial software because I don’t have enough money to buy expensive commercial software and I believe that open source is the best choice (personal opinion)
So I choose Lisa fea software for structural analysis, code aster for non-linear structural analysis, xfoil for airfoil analysis, VLM software for 3d simple analysis (avl or xflr5 aero vsp, or a cheap commercial like Hanley innovations) and OpenFOAM for computational fluid dynamics.
After that, I start to study regulations to make sure that I will design a good plane for me.
At the start, I dream to build a four-seater plane but I think that it is really uncommon to fly with 3 other people, also a four-seater is experimental and it is more expensive to own it, for these reasons I go with the ultralight. But because maybe in future I will need a four-seater, I design it as a four-seater. 2 seats for adults in the front area and 2 seats for children or light adults. Additionally, I plan to build a kit and USA is a very interesting country because it has a lot of excellent homebuilders. For this reason, I designed it as lsa, but strong enough to carry 2 extra children and light enough to fly in Europe as an ultralight. Also, I have to make a low time and easy to build kit, so a well and simple designed composite laminate structure, will be a good choice (maybe the best one).

Quote:

---

Originally Posted by christos

I start a more detailed technical report. Not only because I want to advertise my design but additionally because (I think) some people want to design and built their own planes.
).

---

Advertise your Design ???

I would THINK you need a WORKING model...

THAT would advertise your design.

I see a lot of the 1%......(Thinking about it)

Where the rubber meets the road is BUILDING the plane... the part everybody has trouble with... 99%

There are NO two seat ultralights... You might start by reading WHAT IS AN ULTRALIGHT...

So far... I only see paper airplanes full of hot air
.
Gotta Fly...

I build planes and FLY them , You should try it.
When "I" look at a plane to BUILD...
I look for a proven design .
Kolb and Wittman are both in the Smithsonian Museum

Quote:

---

Originally Posted by planecrazzzy

Advertise your Design ???

I would THINK you need a WORKING model...

THAT would advertise your design.

I see a lot of the 1%......(Thinking about it)

Where the rubber meets the road is BUILDING the plane... the part everybody has trouble with... 99%

There are NO two seat ultralights... You might start by reading WHAT IS AN ULTRALIGHT...

So far... I only see paper airplanes full of hot air
.
Gotta Fly...

I build planes and FLY them , You should try it.
When "I" look at a plane to BUILD...
I look for a proven design .
Kolb and Wittman are both in the Smithsonian Museum

---

We need to be aware of language context and world-wide regulations before we get too critical of somebody's posts. Christo is in Greece and I suspect English is not his native language. Also, the definition of 'ultralight' varies depending on the national regs under which it flies. The European definition of ultralight is considerably different from the USA.

I would like to make clear that when I tell "ultralight" I refer to European ultralight. I told that "fly an ultralight in Europe".
About everything else, I am an engineer. I design it and I will start to build the prototype one of the following months.

I like to write a complete report about design. So when it will be ready everyone will be able to know about r&d of the aircraft.

## thank you Mr Sam.

Quote:

---

Originally Posted by Sam Buchanan

We need to be aware of language context and world-wide regulations before we get too critical of somebody's posts. Christo is in Greece and I suspect English is not his native language. Also, the definition of 'ultralight' varies depending on the national regs under which it flies. The European definition of ultralight is considerably different from the USA.

---

Oh... He seemed to tie it together with LSA... Sorry , Scratch my comment...
.
.
Gotta Fly...
.
Here's some data like yours on a W-10

Quote:

---

Originally Posted by planecrazzzy

Oh... He seemed to tie it together with LSA... Sorry , Scratch my comment...
.
.
Gotta Fly...
.
Here's some data like yours on a W-10

---

interesting

Good evening my friends!
The second part of the design:
Now you know what do you want and you are ready to start the computational part of the design.
1) Select a good airfoil for your operation goals. It is very important. Because if you want a stol aircraft you have to go with a thick airfoil with good lift characteristics, if you want an aerobatic, you have to go with a stall stable airfoil etc. I want a fast long-range traveller, so I need an efficiency airfoil.
For this reason, I select a natural laminar flow airfoil and I developed a simple low operation energy boundary layer controller. It isn’t something new but isn’t common in small planes. But thanks to OpenFoam I develop one for my application. It is a vacuum boundary layer controller and my airfoil will be 85% laminar flow in the upper surface. It will be a simple but very important for aircraft’s efficiency mechanism. It needs only 7 amp and 12 volts. It is small enough to operate in a Rotax version (I am planning to buy one to test the plane). I design it around Rotax engines (rather than I prefer Subaru for a lot of reasons) because it has to operate well with an aeronautical engine if I want to make a kit from it.
Also, I design a cruise flap, but it wasn’t possible to use it with a slotted flap. The slotted flap will reduce the wing’s area, but it becomes too complex to a kit plane. Finally, I choose flaperons. It will operate as ailerons, cruise flap and flap at the same time. It isn’t something new, a lot of LSA and ultralight has flaperons. Some of them for the same reason.

Now you have the first 3d model of your plane.

2) Run a simple vortex lattice method analysis of your aircraft. Make sure that it is good enough for your goals and make a stability analysis. You don’t know exactly centre of gravity, but you will check stability again after you finish finite element analysis of the aircraft.
3) Make your 3d mesh model, choose loads and run your analysis. It seems easy but it is one of the most important parts of your design. Make a good grid to make sure that your results are accurate. Study about your construction materials carefully etc.
4) Run a stability analysis. Now you know the centre of gravity of your plane.
5) Choose computational fluid dynamic software to solve your plane. Vortex lattice method software is good but you have to run it in a really CFD software if you want to take accurate results about stall behaviour etc. There is a lot of software, I go with OpenFoam because it is open source and it is maybe the most powerful CFD software. Keep in your mind that you will need a really good pc. I run complex models and wasn’t possible to run them on a pc and I bought computing hours. It is a good choice.
6) Run a flutter analysis.
7) Run an elasto-plastic analysis (collision)
8) You are ready

**I will post screenshots from software

Thank you!

I'm guessing 6) is Flutter ???
.
Gotta Fly...

PS I see you fixed it... I can't delete this post.

Quote:

---

Originally Posted by planecrazzzy

I'm guessing 6) is Flutter ???
.
Gotta Fly...

---

Yes my friend. I make a mistake, I am sorry about it.
Thank you very much for the comment and for your interest! :-)

Hello, as i promised i make some screenshots of Lisa software. It will make more clear how i make finite element analysis.
If you go with Lisa, you can choose laminate material from the library.
You have to set parameters before you run an analysis. This is maybe the most important part of your design. You have to be sure about boundaries before you run an analysis.



Attachment 7684
In this pic, you can see Lisa's laminate model. You can set both matrix and fiber parameters.


Attachment 7685
In this pic, you can see the model's finite elements.


Attachment 7686
In this pic, you can see another one Lisa's laminate model. Both are highly accurate models.


Attachment 7687
In this pic, you can see the unidirectional carbon tube model.


Attachment 7688
In this pic, you can see results in photorealistic rendering.


Attachment 7689
In this pic, you can see the results' table.