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Optimization

 
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Mustafa Umut Sarac
Ranglisten-Ass


Anmeldungsdatum: 19.09.2018
Beiträge: 204
Wohnort: Istanbul - Turkey

BeitragVerfasst am: 03.09.2019, 13:21    Titel: Optimization Antworten mit Zitat

ps. AFTER READING WIENNESE FRIEND POST , I FOUND SINGLE SPEED OPTIMIZATION MIGH NOT FIT THE REALITY OF BOOMERANGS. hE TOLD ME SPEED VARIES ALONG THE WING AND VARIES ALONG THE PATH. BUT IT DOES NOT DIMINISH THE VALUE OF CONCEPTION. COMPUTER CAN DO A LOT.

I am still not talking on exact equations but experience and sense. But I tried to understand Navier Stokes Equations and some of others.

BUT I posted an article and example picture of single drag optimized ship. You can find all engineering details , equations , algorithms there.

NACA profiles are used by passenger or military aircrafts and used by boomerang makers.

Passenger aircraft wing is optimised for multiple situations , they must be optimized for high wind , low wind , turbulence ,wake, wind coming from multiple angles and different wing angles and multiple drags.

If you optimize a passenger automobile in to one speed , it turns to be a ferrari , if you optimize it to 3 speeds , it turns in to an audi.

If you optimize a ship in to 3 speeds it turns in to flat sided boring steel piece and if you optimize it to single drag , it turns in to art but you cant manufactıure due to its cost.

But we can manufacture every kind of boomerang with 3d printer.

And optimising for one speed doesnt require expensive CUDA GPU card and expensive software. RANS is ideal method for cfd and there are thousands of
papers, books out there for it or optimisation

I think we dont need these aircraft wing profile NACA technology and it is ugly.

Single drag optimized boomerang would be an highly multiple curved artpiece.
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Mustafa Umut Sarac
Istanbul


Zuletzt bearbeitet von Mustafa Umut Sarac am 04.09.2019, 17:53, insgesamt einmal bearbeitet
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B der K-te
Wurfkreis-Choleriker


Anmeldungsdatum: 20.02.2006
Beiträge: 135
Wohnort: Wien

BeitragVerfasst am: 04.09.2019, 13:33    Titel: Antworten mit Zitat

But you still know that a boomerang is a thrown objekt and it spins around one of its axes...
So its moving velocity turns from high after throw to zero at hover. At the end of the wings speed is higher as near the center of rotation. And it adds up vectorially with forward speed. So even during one rotation air flow changes dramatically.

Forget these clean aricraft wing profiles. Most boomerangs works better and best with much more uglier ones.
Also everything has already been tried: smooth surface, rough surface, with and without turbulators...
There is no space for optimization. Belief it or not - or prove it with a real (not theoretical) boomerang that brakes world records.
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Mustafa Umut Sarac
Ranglisten-Ass


Anmeldungsdatum: 19.09.2018
Beiträge: 204
Wohnort: Istanbul - Turkey

BeitragVerfasst am: 04.09.2019, 16:35    Titel: Antworten mit Zitat

Hello,

I think there are immense things that can be done with optimisation. I have posted some of them , look carefully at least to drawings what can optimisation can do. You dont know , you did not see them on boomerangs because computer power newly can do the calculations in few years yet.

As you say , if the all speed differs along the wing band along the path , it can be optimised.

I read some papers on UAV propellers and the simulation results were unbeliviably complex but computer can understand whats going on there in reality and what must be done.

Today engineering is a experience on coding and using softwares. Lots of engineers dont see whats really calculated good , bad , wrong , right in computer.

I learned CUDA from danish friend and its 2000 cores replaced the old softwares and new lot more precise calculations began.

As you can see I have lots of things at my mind and I afraid to focus on single subject.

I think the thing must done collectively. I bet there must be computer , physics , math guys in forum. They do better than me.

I have posted papers and softwares and hardwares and books and codes.

People must awake.

Now you can ask why these excellent softwares does not create extreme shapes. This is question of able to manufacture them.

But boomerangs are the best thing you can try everything you can find in the world , its manufacture is 3d printing.

But I am loosing my patience and may be I can start to do it but it would be very very difficult for me.
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Mustafa Umut Sarac
Istanbul
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B der K-te
Wurfkreis-Choleriker


Anmeldungsdatum: 20.02.2006
Beiträge: 135
Wohnort: Wien

BeitragVerfasst am: 05.09.2019, 09:25    Titel: Antworten mit Zitat

Zitat:
But I am loosing my patience and may be I can start to do it but it would be very very difficult for me.

Oh really? What a surprise.
And you thing for us it's easy going?? It's easy to talk wisely.
Zitat:
I bet there must be computer , physics , math guys in forum.
This bet you are loosing. Not in this dead forum. You have to go to another one.

Zitat:
As you say , if the all speed differs along the wing band along the path , it can be optimised.

That's exactly the opposite of what you wrote before. Optimization may be possible for one special case, not if you have to cover many conditions.
Zitat:
I think there are immense things that can be done with optimisation. I have posted some of them , look carefully at least to drawings what can optimisation can do.

I read your boring posts but have not found a single thing that would be applicable to boomerangs. All of them were studies not transferable to conditions of boomerangs works. You are not the first guy who thought about bionic and the benefit for boomerangs. And as I wrote, this also was tried back in time before you even had an idea about it.
It is much more faster to build a new invented boomerang to try it as to think and simulate it.
For Fast-Catch and Trick-Catch boomerangs they are playing with lot of drag, no need to optimize the profile. Better get exercise to master the throw and the boomerang itself.
3D-printing a boomerang? For these boomerangs which are worth to optimize, the printable material is not stiff enough. So it's waste of time.
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mschuetz
Wurfkreis-Choleriker


Anmeldungsdatum: 21.02.2004
Beiträge: 136

BeitragVerfasst am: 07.09.2019, 13:15    Titel: Antworten mit Zitat

Don't see the problem you guys have which each other. Why not just try to profit where it's possible from each other?
Not for every case an optimization is really computable. Agreed. But: For special cases like MTA hover the data of naca or similar airfoils are essential! Ignoring the work done by georgi dimantschev in the 1990's and keep doing so was and is a big mistake. Lots of throwers were not taking science as serious. Me included, 20 years ago. Understanding the role of the pitching moment of an airfoil made it possible for me to design symmetrical MTA threebladers which stay stable during hover. No "death spirals" with crash anymore.
Unfortunately for other cases where there isn't a steady state condition it is very very complex! Yes, for Fast Catch a certain amount of drag is important. Not to gain velocity but to gain control. An 1.5s FC boom is worthless if it works only indoor. Kind of a performance/risk optimization.
3d printing: Michel Appriou has repeatedly printed boomerangs for himself and the french kids. I've seen them flying! They are solid, comparable with triflies. A dream! You can print a series of booms with slight changes...
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mschuetz
Wurfkreis-Choleriker


Anmeldungsdatum: 21.02.2004
Beiträge: 136

BeitragVerfasst am: 07.09.2019, 13:46    Titel: Antworten mit Zitat

Don't see the problem you guys have which each other. Why not just try to profit where it's possible from each other?
Not for every case an optimization is really computable. Agreed. But: For special cases like MTA hover the data of naca or similar airfoils are essential! Ignoring the work done by georgi dimantschev in the 1990's and keep doing so was and is a big mistake. Lots of throwers were not taking science as serious. Me included, 20 years ago. Understanding the role of the pitching moment of an airfoil made it possible for me to design symmetrical MTA threebladers which stay stable during hover. No "death spirals" with crash anymore.
Unfortunately for other cases where there isn't a steady state condition it is very very complex! Yes, for Fast Catch a certain amount of drag is important. Not to gain velocity but to gain control. An 1.5s FC boom is worthless if it works only indoor. Kind of a performance/risk optimization.
3d printing: Michel Appriou has repeatedly printed boomerangs for himself and the french kids. I've seen them flying! They are solid, comparable with triflies. A dream! You can print a series of booms with slight changes...
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Rasmus Sorensen
Bullseye-Küken


Anmeldungsdatum: 20.09.2019
Beiträge: 2

BeitragVerfasst am: 20.09.2019, 13:18    Titel: Anleitung Antworten mit Zitat

Um gute Ergebnisse zu erzielen, benoetigt man das geeignete Material; am besten schichtverleimtes Sperrholz. Fuer den Bumerangbau hat sich "finnisches Birkensperrholz" (Flugbausperrholz) mit 2 Schichten pro mm bewaehrt.

Fuer den Anfang genuegen :
Bauplan mit eingezeichneter Profilierung
Laubsaege/Stichsaege
mittelgrobe Holzraspel
Feile
2 Schraubzwingen
Bleistift
100er und 180er Schleifpapier
Grundierung, Lack (Spraydosen oder Streichlacke)
Pinsel

Arbeitsschritte:

Bumerangschablone (Pappe) erstellen
Umriss auf Sperrholz uebertragen (Linkshaender die Schablone spiegelverkehrt auflegen); dabei beachten, dass die Vorlage auf die am Rand nach oben gewoelbte Holzseite aufgezeichnet wird.
Den Rohling aussaegen
Das Profil aufzeichnen (Achtung Linkshaender! Spiegelverkehrtes Profil) Zeichnung 1
Mittels Schraubzwingen den Rohling auf einer Tischkante festschrauben
Das Profil mit der Raspel herausarbeiten und mit der Feile nacharbeiten (Profilbeispiel Zeichnung 2)
Mit 100er Schleifpapier nachschleifen und mit Schnellschliffgrundierung (Clou-Schnellschliffgrund oder aehnliches) behandeln.
Nach Trocknung den Bumerang mit 180er Schleifpapier (evtl. auch feiner) glaetten
Den Bumerang testen (siehe Wurfanleitung)
Eventuell noch das Profil nachbessern
Abschliessend, je nach Geschmack, mit Farb- oder Klarlack schuetzen.

Fuer Bildmaterial – gerne PM.
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