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Jul 06, 2019, 11:23 AM
just Some Useless Geek
Enough experimental data is itself a form of scientific research, Dick. Thousands of modelers have built your wings and are using them very successfully. They don't all report their findings, and even fewer have measurements to back up their conclusions, but the overall effectiveness of your wings is undeniable.

As has been pointed out many times before: you didn't start out to impact the small airframe market with your science, but its effect on what we build has generational consequence. Everybody who has slapped a smaller sheet of foam on top of a bigger sheet and called it a KFm2 owes you a debt of gratitude.
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Jul 06, 2019, 04:47 PM
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Dickeroo's Avatar
Quote:
Originally Posted by A Useless Geek
Enough experimental data is itself a form of scientific research, Dick. Thousands of modelers have built your wings and are using them very successfully. They don't all report their findings, and even fewer have measurements to back up their conclusions, but the overall effectiveness of your wings is undeniable.

As has been pointed out many times before: you didn't start out to impact the small airframe market with your science, but its effect on what we build has generational consequence. Everybody who has slapped a smaller sheet of foam on top of a bigger sheet and called it a KFm2 owes you a debt of gratitude.
Thank you. I owe a great deal of gratitude to all the RCers out there who were willing to try out the KF concept. Their creativity, experimentation and innovation has opened up the idea of trapping a vortex to a much larger world. It is an amazing story.

~ Dick Kline
Aug 31, 2019, 03:34 PM
Registered User
Hey guys,

do you have some Infos about the under cambered versions and FKM7 - KFM10 ?
Aug 31, 2019, 07:10 PM
Jack
jackerbes's Avatar
I've never heard of those, can you post any links to more information about them?

At any rate, if you ant to experiment with it, try adding a step or steps to an under cambered wing and test fly the two wings. Tell us what your find out...

Jack
Sep 07, 2019, 11:21 PM
just Some Useless Geek
My guess would be that a step on the top side of the hollow camber wing would have less effect than what would be apparent on an otherwise flat plate wing, but the step should still provide a rise in the lift centroid (if my theories are correct) and an increase in overall stability, particularly at lower speeds. Also, slower and draggy.
Sep 08, 2019, 04:49 AM
Jack
jackerbes's Avatar
@ stereodreieck86,

Don't know if you are still reading this thread but, for more info on the KF airfoil, the original thread about the airfoil is here:

** Kline-Fogleman Airfoiled Flying Wing ** - https://www.rcgroups.com/forums/showthread.php?558321

Post #1 in that thread has a *.pdf file that has some comparison testing that was done by Rich Thompson (Kaos2) and I have attached that document here too.

Beyond that, google searches and browsing this thread and the KF building and flying thread are the best places to find more info or links to more info...

The bottom line to me is that for building wings with flat plate materials (i.e., various types of sheet foams for the most part) the KF wing is faster and easier to build and will fly better than any simple single sheet flat plate wing. If there is a penalty it is that the wing might need a little more power to overcome the slightly higher drag that comes with the KF's increased weight and thickness.

And my opinion as a pilot is that the KF wing is more stable in flight (less stalling or tip stalling) than most or all of the other wing types.

Jack
Sep 08, 2019, 10:37 AM
Registered User
Thank you Jack,

I am active in all KFM threads and generally speaking very active in other forums like the german RC-Network and FPV-Treff.

Quote:
The bottom line to me is that for building wings with flat plate materials (i.e., various types of sheet foams for the most part) the KF wing is faster and easier to build and will fly better than any simple single sheet flat plate wing. If there is a penalty it is that the wing might need a little more power to overcome the slightly higher drag that comes with the KF's increased weight and thickness.
That's still a question that remains unanswered since some studies /papers say; KFM makes the airfoil a little bit more draggy but the lift increases over proportionally.
I am gonna link the PDF when I find it.

On top of that, the KFM7 - 11 is still a mystery because nobody does research on them (as far as I know).

The RICH THOMPSON paper let's say is at least problematic because we don't know how he got to these results! Where all Configs tested the same day, with the same conditions and the same angle of incidence, we don't know.

The general consent is that KFM is not suitable for higher quality RC airplanes and Fullscale (which is misleading) but a somewhat similar Idea (from Felix Schaller) shows big improvements under all circumstances!
http://www.felixschaller.com/index.p...ews/89-aniprop
http://www.felixschaller.com/index.p...e-aerodynamics
Sep 08, 2019, 11:05 AM
Registered User
Dickeroo's Avatar
Quote:
Originally Posted by stereodreieck86
Thank you Jack,

I am active in all KFM threads and generally speaking very active in other forums like the german RC-Network and FPV-Treff.


That's still a question that remains unanswered since some studies /papers say; KFM makes the airfoil a little bit more draggy but the lift increases over proportionally.
I am gonna link the PDF when I find it.

On top of that, the KFM7 - 11 is still a mystery because nobody does research on them (as far as I know).

The RICH THOMPSON paper let's say is at least problematic because we don't know how he got to these results! Where all Configs tested the same day, with the same conditions and the same angle of incidence, we don't know.

The general consent is that KFM is not suitable for higher quality RC airplanes and Fullscale (which is misleading) but a somewhat similar Idea (from Felix Schaller) shows big improvements under all circumstances!
http://www.felixschaller.com/index.p...ews/89-aniprop
http://www.felixschaller.com/index.p...e-aerodynamics
Gentlemen...
You might find this document interesting as it compares a thick airfoil and a thin airfoil against a combination of the two while adding a KFm4.
~ Dick
http://jafmonline.net/JournalArchive...7&issue_ID=252
Sep 08, 2019, 11:12 AM
Registered User
Hey Dick,

that's the paper I mentioned. Thank you.
Sep 08, 2019, 03:22 PM
Registered User
Dickeroo's Avatar
Quote:
Originally Posted by stereodreieck86
Hey Dick,

that's the paper I mentioned. Thank you.
Here is another document that you might find interesting....

https://curve.carleton.ca/system/fil...dfixedwing.pdf
Sep 15, 2019, 07:58 AM
Registered User
Quote:
Originally Posted by Dickeroo
Here is another document that you might find interesting....

https://curve.carleton.ca/system/fil...dfixedwing.pdf
I think we have to do a Skype session or something like that, discuss the results and how they translate into the RC model world, are you in?


Here are some quick and dirty thoughts on Site 46 to 47, Fertis did some research at various speeds but the graph only shows the results at Highspeed (200kmh) and unrealistic Reynolds numbers (470000). Would love to see results at Low RN.
Sep 21, 2019, 06:59 AM
Registered User
Dickeroo's Avatar

1987...A bit of KF history... the first manned flight.


Dick Wood... he is the man who first flew a KF stepped airfoil. This video took place in Canada.

Kline Fogleman Airfoil First Manned Flight (22 min 54 sec)
Oct 05, 2019, 12:43 PM
Registered User
Dickeroo's Avatar

Solar RC aircraft heading our way...


SOLAR Plane V4 Flying Wing with KF airfoil
SOLAR Plane V4 Flying Wing - RCTESTFLIGHT (17 min 14 sec)


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