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

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christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
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.


1.jpg

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

2.jpg

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

3.jpg

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

4.jpg

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

6.jpg

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

7.jpg

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

Well-Known Member
Joined
Nov 29, 2010
Messages
81
Location
USA
Could you share the design specifications (Reynolds number, Cl, …) and performance characteristics of your airfoil? Thanks, Doug
 

christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
Could you share the design specifications (Reynolds number, Cl, …) and performance characteristics of your airfoil? Thanks, Doug
Dear Sir Doug,

Do you want airfoil's specs with or without vacuum? in which kind of speed?

Thank you very much for your interest
 

Retiree

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Joined
Nov 29, 2010
Messages
81
Location
USA
Dear Sir Doug,

Do you want airfoil's specs with or without vacuum? in which kind of speed?

Thank you very much for your interest
Hi Christos,
What I was interested in for specs:
design lift coefficient and Reynolds number at cruise, climb;
design thickness, zero lift pitching moment.
If you have a plot of the lift vs drag at the cruise Reynolds number that would be good too.
Thanks!, Doug
 

christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
Dear Doug,

Boundary layer controller off:
Max continuous speed (245km/h), lift coefficient=0.189 and Reynolds number 5.37e6
Best range speed (182 km/h), lift coefficient=0.343 and Reynolds number 3.99e6
zero lift pitching moment (max continuous speed) -0.042
Design thickness 14.3%

Boundary layer controller on:
Max continuous speed (255km/h), lift coefficient=0.173 and Reynolds number 5.6e6, 4% faster
Best range speed (182 km/h), lift coefficient=0.343 and Reynolds number 3.99e6, speed is the same but the economy is 12.5% better.

I will share plot tomorrow because now i am not in my home and i don't have it :)
 

christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
It's a long time since my last post.
The month was too busy. I had a lot of technicals problem with the dam's rebuild. Finally, I solve all of them but it wasn't easy. Now its' vertical slide gate operates smooth and soon will be ready to work the radial overflow gate also.

About the aircraft's project, i made some 3d drawings and i will start to build it. A high experienced composite builder here in Greece will make moulds and the first plane. Of course, i will help him, not only to reduce cost but also because i like it.

I will keep notice and photos from the build and i will share it with you, and i hope that you will enjoy it.

I need a little time of course because i have to solve some technical problems. For example, I have to measure other similar aircraft's cockpits and compare with my own to make sure that it will be comfortable enough. I have to make a research on the vacuum suction's construction because i want to make sure that it will be easy and comfortable to use for the pilot etc

Some 3d views of the aircraft. Additionally a drag polar with and without suction, you can see the benefit in drag. I hope that you will like it.

I will post tomorrow or day after tomorrow some magnitude pic with and without suction to make more clean the suction's benefit in the boundary layer.

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a6.jpg
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christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
Some analysis' software screenshots (OpenFOAM). You can see the boundary layer benefits.
Also, i calculated the cost for a complete aircraft and i believe that it is affordable enough.

Best regards


blc-off.jpg
pic 1: blc off
blc-on.jpg
pic 2:blc on
 

Retiree

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Joined
Nov 29, 2010
Messages
81
Location
USA
Hi Christos,
What boundary layer control method are you using, sorry if I missed it in your posts. And, have you validated your CFD method for the boundary layer control method you are using?
 

Retiree

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Joined
Nov 29, 2010
Messages
81
Location
USA
I had a close look at the lift vs drag curve. The base airfoil you are using looks pretty good with a Cd,min of about .003. What airfoil are you using?
 

christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
I had a close look at the lift vs drag curve. The base airfoil you are using looks pretty good with a Cd,min of about .003. What airfoil are you using?
Dear Sir,
I am sorry for the delay.
I am using a vacuum boundary layer controller. I believe that it is better than the microjets boundary layer controller because of lower operation power.
 

Retiree

Well-Known Member
Joined
Nov 29, 2010
Messages
81
Location
USA
Hi Cristos,
What is your strategy for the boundary layer control? Are you planning on vacuuming off all the boundary layer?
Doug
 

christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
Hi Cristos,
What is your strategy for the boundary layer control? Are you planning on vacuuming off all the boundary layer?
Doug
Dear Sir Doug,
I am planning on vacuuming enough amount of boundary layer to make an 85% laminar airfoil (basic airfoil is 70%). It is enough for a 12,5% better efficiency at cruise speed.
I choose 85% laminar for better aileron behaviour.
Also, it is ideal for a Rotax engine!
I designed aircraft around Rotax engines (rather than i will use a Subaru engine for my own, i will use ea71 which is getting close to 80hp Rotax)
It will be a fast and efficient aircraft, i designed it for long trips, i like long trips
 

Retiree

Well-Known Member
Joined
Nov 29, 2010
Messages
81
Location
USA
Hi Christos,
Thanks for all the information. I hope you will also share with us the minimum predicted drag coefficient of your airplane.
Thanks again, Doug.
 

christos

Well-Known Member
Joined
Nov 9, 2018
Messages
50
Location
Greece
Hi Christos,
Thanks for all the information. I hope you will also share with us the minimum predicted drag coefficient of your airplane.
Thanks again, Doug.
Dear Sir Doug,

Of course, it is not a problem. Lowest Cd value (0.0188) tie out the long-range's speed (182 km/h or 100 knots) and it is one of the best in its category. Also, Cdo is 0.01262.
 
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