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Nov 06, 2018, 10:47 AM
treefinder
springer's Avatar
Quote:
Originally Posted by gpw
Once we found out it worked , we gladly accepted it and used it happily on many models … I don’t need to understand why the sky is Blue to appreciate it …
I agree with you, but, doggonit, we all have our own variation of the hobby, and if one of us likes to play with cfd and tunnel testing i say go for it and post results, just like we post our templates in build threads! I was playing with the idea of following the Wrights and making a small wind tunnel half for the challenge of getting it to work, half for what it would tell me. Then i came to my senses and built some more foamies!
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Nov 06, 2018, 12:21 PM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Yes , you’re absolutely right … I often forget not everybody is new to the hobby , and just looking for something easy to build and fly …

Springer , I believe the Wrights funded their experiments off a lucrative Bicycle business ??? … Must read up on that … ( Enter: fact checkers ) The closest we ever got to a wind tunnel was a washing machine cardoard box with “vanes” inside ( airflow straighteners ), and a Box fan with duct tape … We were able to “fly” a suspended model in the airstream … a little … Not very useful … So , like you , we too went back to building more planes … Cardboard box got recycled … Box fan wore out … ( all that "flying” …. hahahaha )

Once we first found out about the KF , we jumped right on it and started making new wings … so easy ..Positive results flying , and really strengthened a flat foamie wing significantly …
Last edited by gpw; Nov 06, 2018 at 12:33 PM.
Nov 06, 2018, 12:32 PM
treefinder
springer's Avatar
You and those of us who learned to fly rc with a T1 need to continue to "evangelize" with the simple easy to build and repair designs so those who express interest can get the foam addiction and the enjoyment that comes with it so they will progress and perhaps become the aerospace engineers who combine education and hobby for more knowledgeable fun! And i know you will!
Nov 06, 2018, 03:04 PM
flyin' fool
goldguy's Avatar
I also agree. Experiment and explore and post it. That's how we all got here, sharing ideas and designs no matter what they are.

But, it would be convenient to keep all the information in one thread, especially one that stays up at the front of the line up. Lots of stuff lost at the end of all these forms that deserve more attention.
Nov 06, 2018, 04:31 PM
An itch?. Scratch build.
eflightray's Avatar
But then, any true 'registered' airfoil with have a set of coordinates which can be used over and over again if testing and should give repeatable results.

KFm airfoils can be slightly different every time someone makes one, there are no fixed coordinates.

By all means do wind tunnel tests if you want to, but if you want others to use the results, do try to specify exact sizes and surface finishes, and the coordinates, otherwise the data and results may just not be repeatable.

Even slight changes in the shape can give different result.

.
Nov 06, 2018, 07:47 PM
Build straight - Fly twisty
Whiskers's Avatar
It is amazing what works as a wing shape at the sizes we typically use.
Indoor aerobatic models which the experts fly with superhuman perfection have flat plate airfoils, mostly with a rectangular leading edge. Indeed I have seen it said that the flat leading edge is greatly superior to a rounded or sharpened leading edge in this application.
I could be that the static zone on the squared off leading edge acts as an adaptive virtual edge, creating a turbulent bubble that helps by forming a virtual airfoil shape.
A while ago a guy posted here a design for a disc shaped wing thing, and he was adamant that the leading edge should be left square and not rounded off.
There is nowhere in full-size aviation where this concept is used, or if it is I don't know of it.
Nov 06, 2018, 08:56 PM
http://bit.ly/2zm6gK7
I certainly plan to continue my studies and post the results if it helps, I can keep them in a more appropriate pre-existing forum or keep a master thread of my research.

Also I will definitely start recording / sharing model files and, if I figure out a panel code that works, point .dat files as well.


For reference, I have a thread in Modelling science. I will probably make a master thread there or add to the existing KF airfoil thread
Last edited by corsair2014; Nov 06, 2018 at 09:02 PM.
Nov 06, 2018, 09:28 PM
Registered User
Quote:
Originally Posted by goldguy

But, it would be convenient to keep all the information in one thread, especially one that stays up at the front of the line up. Lots of stuff lost at the end of all these forms that deserve more attention.
You know, practically your entire contribution to this thread has been disparaging or at least negative tone. If you don't like the content, what keeps you coming back? Just unsubscribe.

Personally I hate mega threads. Pearls of wisdom within might as well not exist since search engines so often can't extract what you need. But mostly, people should be free to participate in good faith as they see fit without being subjected to repeated rebuke. No one HAS to read it.
Nov 06, 2018, 09:56 PM
Build straight - Fly twisty
Whiskers's Avatar
Quote: Personally I hate mega threads. Pearls of wisdom within might as well not exist since search engines so often can't extract what you need.
Mega threads only exist because a great number of people are interested in the topic.
If your level of knowledge is such that you need to access the "Pearls of wisdom within" then reading the whole thread may be an excellent way to find some other "pearls" you didn't know existed.
Every time I research a subject, the more I learn, the more I find out how much more there is to learn.
Nov 06, 2018, 11:26 PM
flyin' fool
goldguy's Avatar
I only suggested that his information be posted in a thread that was already established ............….and why.

I never said anything that was negative about his interest or goal in researching the subject. In fact, I even encouraged it and also pointed out to him where he could find information on the KF and RNs.
Last edited by goldguy; Nov 07, 2018 at 01:06 AM.
Nov 07, 2018, 07:52 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Gentlemen , let us remain congenial lest the Moderator show up and shut the whole thing down …. or worse …
Latest blog entry: Lost plans
Nov 07, 2018, 08:41 AM
http://bit.ly/2zm6gK7
Yesterday I started experimenting in my CAD program to develop a way to quickly generate variations of KF airfoils that remain as consistent as possible in their design (leading edge radius etc) so that I can test a large amount of airfoil designs in my CFD program and tabulate/compare the results.

I will temporarily (i'll close it once i finalize the design format) be making a new thread to discuss how i set this up and to get feedback. I'll post a link here in a bit once I get it setup
Nov 07, 2018, 09:06 AM
http://bit.ly/2zm6gK7
Excited to hear your input: https://www.rcgroups.com/forums/show...s#post40447406


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