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Unstallable, Multiple Slot, Coanda Effect Boomerang Airfoil

 
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Mustafa Umut Sarac
Ranglisten-Ass


Anmeldungsdatum: 19.09.2018
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BeitragVerfasst am: 18.11.2019, 12:26    Titel: Unstallable, Multiple Slot, Coanda Effect Boomerang Airfoil Antworten mit Zitat

Some of the do it yourself aircrafts are designed for extremelly low speed flight , lets say 90 kmph.

In this speed , most of the aircrafts cant fly and dives in to stall.

But they design new unstallable wings with coanda effect for these crafts.

I will add their pictures below.

These wings are for extreme high angle of attack and extreme low speeds. And they do perform better in normal conditions.


DETAILED ANALYSIS LINKS :


FIRST, ZENITH AIRCRAFTS WEBSITE :

www.zenithair.net



SECOND IS A TRIPLE SLOT AIRFOIL DETAILED RESEARCH PAPER:

Experimental Investigation of a Handley Page Triple Slotted Aerofoil
Lazaro Coelho, Marco Placidi, Chris Atkin and Zhengzhong Sun
Department of Mechanical Engineering & Aeronautics, City University London, London, UK

Abstract A triple slotted aerofoil following the Handley Page 44F design was tested at City University London T-2 wind tunnel. The model allowed the study of a fixed triple slotted wing as well as investigation of the effects of isolated slots at different locations along the chord. PIV measurements were performed within the chord Reynolds number range in between approximately 200,000-400,000. The model was tested at an angle of attack of 22o . Measurements of mean streamwise velocity, velocity fluctuations
and shear stress were analysed. The study shows how an isolated slot is more favourable when it is placed closest to the leading edge, although slow moving fluid regions can still be found close to the trailing edge. Fully attached flow was only achievable by using all three slots. In addition, the fully slotted profile is shown to generate channel exit velocities in the order of 1.4U∞, which highly energise the boundary layer on the suction side.



PAPER IS HERE :

https://drive.google.com/file/d/1q2lrzJcriWnvxz9SFxIYDSXkjwlOHV1s/view?usp=sharing

















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B der K-te
Wurfkreis-Choleriker


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BeitragVerfasst am: 18.11.2019, 15:11    Titel: Antworten mit Zitat

They perform better in normal conditions...
Well, what are normal conditions for a boomerang? Flying near stall? Don´t think so.
Okay, slats are not really new (1918) and you can print them in 3D. Where at the boomerang wing would you put these? They are sure usefull if angle of attack is quite high, over 15° as you see in pictures above. The probem, drag is also really high at that angle. Thats fine for an airplane landing to lose speed but not for a boomerang.
No advantage without disadvantage.
Is there something told about drag in the paper? I can`t open the link to the google drive.
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Mustafa Umut Sarac
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BeitragVerfasst am: 18.11.2019, 15:26    Titel: Antworten mit Zitat

I tried the drive link and it works. Its a technology called high lifting surfaces and in normal flying conditions , you have more lift. Its applied from model aircrafts to fighter jets to passenger aircrafts.

At normal flying conditions , you have lot more lift.

try the drive link and please report me back. It works for me but I dont know the others.
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Mustafa Umut Sarac
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BeitragVerfasst am: 18.11.2019, 15:40    Titel: Antworten mit Zitat

If you look to the graph attached , with single front slot , you have %100 more lift than NACA airfoil at dropped speed and stall conditions.

You have % 50 more lift at same angle of attack.

I think an MTA with slot have more chance to survive with lowering thermals.

Think reverse , you dont have to put a extra piece in front of wing. You have to open an slot.

I have been posted water tank test , wind tunnel tests and older test methods which does not require writing codes or renting super computer.

As Marx says , it depends to history to find the things use.

I will look in to drag , lets see.
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Mustafa Umut Sarac
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BeitragVerfasst am: 18.11.2019, 15:59    Titel: Antworten mit Zitat

Weick, F., Shortal, J. “The effect of multiple fixed slots and a trailing edge flap on the lift and drag of a clarck Y airfoil” NACA Report 427, 1933

As You see above , multiple slots idea goes back to 1933 or earlier.

London University Paper discusses about two things.

First more lift but more drag but it depends on configuration.

Second triple slots or lets say 4 different wings on same axis with gaps have only the attached flow , this is good thing and lot less drag.
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B der K-te
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BeitragVerfasst am: 18.11.2019, 16:08    Titel: Antworten mit Zitat

I can open the link using my smartphone. It does not work at my PC - fine.

Seach for "drag" in the paper and you will find this: "[...] resulting in increased lift coefficient, CL (at a price of increased drag)."
quod erat demonstrandum

Aircrafts have other normal conditions then thrown and spinning boomerangs. Please don´t mix it. You posted papers from Manuel. There you can read about air flow direction over a forward moving AND spinning boomerang wing.
Slats on aircrafts are movable - to reduce drag at higher moving speed.

I know that you just have to open a slot...
By the way, it´s not so easy to do that accurate at this size of wing.
I want to know where you would do that at the wing. At the end, near the center of gravity or every else? Where do you have these angle of attack to use slats?
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Mustafa Umut Sarac
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BeitragVerfasst am: 18.11.2019, 16:28    Titel: Antworten mit Zitat

Paper discusses opening slot near to coming flow , its says better.

As I wrote before , without constructing wind tunnel or hydro tank , without using evaporating paint method - I posted 3 threads - or without spending few thousand euros on a super computer , you will never know what to do.

Its not a matter of carpentry and its more than human creative or calculation power.

As you cant design a fighter jet on paper or you can with couple of thousands of engineers and spending 10 years,

my friend you will never know what to do. I am sorry.

I am searching for an answer. I am thinking to construct an analog computer for flow simulation.
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Mustafa Umut Sarac
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BeitragVerfasst am: 18.11.2019, 17:00    Titel: Antworten mit Zitat

But there is a hope.

The easiest and most creative flow optimization or shape optimization done on a artificial intelligence. You have to train an neural network group with simulation results of different situations. Than when you show it a different configuration , it simulates it fast. How fast , I dont know. Than you train an NN with optimisations and it creates most creative results ever a computer did.

Amazon Web Services have trainable NN softwares and with spending 500 euros , you are at somewhere.

And there is 80s NASA genetic algorithms , they are raw output. They had to wait other 40 years to put the inventions in to production.

And you have to learn mathematics , computer science etc.

Best way , is to buy a cuda card and pc and construct your hydro tank or aero tunnel and go from there. You have to buy an 3d printer for samples.
Its another 2000 euros expense.
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mschuetz
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BeitragVerfasst am: 18.11.2019, 21:46    Titel: Antworten mit Zitat

Don't forget: An MTA has to gain height and hover! Any additional drag will be a disadvantage for the first part of the flight.
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BeitragVerfasst am: 18.11.2019, 22:59    Titel: Antworten mit Zitat

Manuel,

We can install an ic and micromotor to control the gap. For first part of the flight , the gap might be tight but slower the boomerang , wider the gap.

This can be done with basic micromechanism also. As 3d printer prints your wing and airfoil , fdm can print an gear , cantilever and a spring. An electromagnet can activate the mechanism to widen the gap.

Solidworks or AWS Robot can design such a thing.

At graphic , the single slot , flapped airfoil have %50 more lift , at 25 degrees , this is %100 more.

An single 0.1mm thick wire on the wing , can be heated with battery and when it cools and resistance been lower , everything allright. When resistance increases with lower wind speed , gap would be opened.

This mechanisms , electronics are simple.

but the airfoil is not.

XFOIL comes to my mind.

Can XFOIL design such a airfoil ?
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Mustafa Umut Sarac
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BeitragVerfasst am: 18.11.2019, 23:18    Titel: Antworten mit Zitat

Manuel,

Paper tells about only triple slotted design have the attached flow.

Mechanisms , sensors can make everything very interesting. This first prototype could have two options , opened or closed but flaps and gaps can be differantial also.

mechanism must be lightweight but it must be impact resistant also.

too many things can be done.
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mschuetz
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BeitragVerfasst am: 19.11.2019, 00:10    Titel: Antworten mit Zitat

Not allowed in competitions if operated with power. Interesting for research but currently irrelevant for competitive boomerangs. Without micromotors etc: Shape-changing airfoils would be interesting, agreed!
Manuel
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Mustafa Umut Sarac
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BeitragVerfasst am: 19.11.2019, 06:22    Titel: Antworten mit Zitat

Manuel,

You are expert on XFOIL. Can XFOIL design such a triple slotted or exotic airfoils ?

Can XFOIL optimize a raw design ?

By the way , do competition rules , rules out the shape changing airfoils ?

Thank you,
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AndreasJacob
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BeitragVerfasst am: 02.12.2019, 08:50    Titel: Antworten mit Zitat

Your experiments are incredible! from where you collect these informations I want to know about it!
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BeitragVerfasst am: 02.12.2019, 09:26    Titel: Antworten mit Zitat

Hello Andreas,

I researched gas turbines 25 years. I have been encountered with many many different technologies , I read hundreds of NASA papers , DTIC papers. I have broad lines of hobbies. These comes from that experience.

I have put to the forum as much as I know.

Thank you and welcome to the forum.
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