Scracth Build Cessna 337

[redblur]

With KF airfoil
the same builder of the Flyin truck







Want more KF airfoil Scractch Build??

[LittleGiant]

Got video?

Very interesting

[redblur]

Don't have
but the Perfomance so nice

[LittleGiant]

Don't have
but the Perfomance so nice

So does the rear propeller actually spins?

[Leo]

I made two little flying wings (40% and 50%) just to test. One with step on top but both only fly well with the step at the bottom.
I did a test with both plane free fall with nose point down, to my surprise, both auto level themselves with step at the bottom.

[redblur]

So does the rear propeller actually spins?

the rear Doesn;t Spin just a Decoration....

if spin the plane will be Over powered

@leo
nice fly wing

elevon?

[dickeroo]

This might help explain the KF airfoil concept.

The concept behind the Kline-Fogleman airfoil may be hard to understand because it is so different from present aerodynamics. The KF concept uses a vortex, which attaches itself to the KF airfoil behind the step and becomes part of the airfoil. This means that one-quarter of the KF airfoil is air against air. This also means less friction and greater efficiency penetrating the air. It is important that the step be between 7% and 9% at 50% of the chord on top. When the step is on the bottom, the step should be at 40% of the chord. When the step is on top, it will produce higher lift than on the bottom, but the airfoil works well right side up or upside down. Below is a graphic picture which shows how the KF airfoil concept works. A picture is always worth a thousand words.

Dick Kline

[Leo]

The concept behind the Kline-Fogleman airfoil may be hard to understand because it is so different from present aerodynamics. The KF concept uses a vortex, which attaches itself to the KF airfoil behind the step and becomes part of the airfoil. This means that one-quarter of the KF airfoil is air against air. This also means less friction and greater efficiency penetrating the air. It is important that the step be between 7% and 9% at 50% of the chord on top. When the step is on the bottom, the step should be at 40% of the chord. When the step is on top, it will produce higher lift than on the bottom, but the airfoil works well right side up or upside down. Below is a graphic picture which shows how the KF airfoil concept works. A picture is always worth a thousand words.

Dick Kline

Thks for the info.
But why both of my little flying wings will level themselves with the step at the bottom? Can I conclude that step at the bottom is more stable?

[dickeroo]

How I invented the Kline-Fogleman airfoil.

Thks for the info.
But why both of my little flying wings will level themselves with the step at the bottom? Can I conclude that step at the bottom is more stable?

I originally created the Kline-Fogleman airfoil from making a paper airplane. This happened over forty years ago. When I created the paper airplane it had the step on the bottom and flew extremely well. It would not stall and had great air penetration. Then, I tried the step on top. It flew even better, but needed a small amount of reflex. In wind tunnel tests, it showed that the step on top produced higher lift over drag ratios. Fogleman and I obtained a patent on this design, however, we were completely rejected by the experts. Their improper testing of the KF airfoil was a disaster. Plus, they never tried it on an actual aircraft, but instead did testing using conventional methods. This did not reveal the true properties because they weren't looking for them. In 1985, I wrote a book about my experiences called "The Ultimate Paper Airplane." Only now, because of the RC Groups experimentation have the true properties become a reality. There is so much more I could tell you, but this space does not permit. New ideas are never embraced by those with authority. It is too far outside their box. It also threatens their expertise.

To date, no negatives have shown up on the KF airfoil. Here is a brief list of the KF advantages: 1- The KF airfoil has a very wide speed range from very slow to very fast. 2- It has a much better Center of Gravity at 40% vs. 33% for conventional airfoils. 3- It has great control authority at all angles of attack. 4- It has better air penetration than conventional airfoils. 5- It has a higher wing loading than conventional airfoils with a very forgiving CG. 6- It is basically unstallable if properly balanced. 7- It flies as well right side up as upside down. 8- It has a very true tracking through the air which makes for a better photography platform. 9- It does not require reflex which adds to drag.

I hope I have been able to answer your questions to your satisfaction. Please let me know your experiences with the KF airfoil. It pleases me so much that you find it of interest.

[renold]

KF Airfoil

Hi Dick Kline,

When I first look at the your KF Airfoil design, it reminds me on the subject of separation in the wake. This is especially on sudden change in section on a submerged body, airfoil in this case. When air flow separation occurred, the end result will be stall.

However, this is classical fluid mechanic and naturally the expert will not accept this new idea.

I saw my RC buddy who has built a speed glider with airfoil similar to the KF Airfoil. I saw the glider flew twice which climbed 60 deg. with speed. However this scenario is not sufficient to establish the theory of KF Airfoil. As the 3D planes with flat wing sheet could do the same. But looking at the way the speed glider glides with motor off, it just behave like what a glider does. That is no sign of stall.

I am think there are still possibilities of testing this airfoil concept. It would be interesting if there are photos showing stream line formation in smoke tunnel. Since there are drag and lift measurements. There should be potential developments on the KF Airfoil, my thinking.

[dickeroo]

This picture shows what happens with a step on a car.

Hi Dick Kline,

When I first look at the your KF Airfoil design, it reminds me on the subject of separation in the wake. This is especially on sudden change in section on a submerged body, airfoil in this case. When air flow separation occurred, the end result will be stall.

However, this is classical fluid mechanic and naturally the expert will not accept this new idea.

I saw my RC buddy who has built a speed glider with airfoil similar to the KF Airfoil. I saw the glider flew twice which climbed 60 deg. with speed. However this scenario is not sufficient to establish the theory of KF Airfoil. As the 3D planes with flat wing sheet could do the same. But looking at the way the speed glider glides with motor off, it just behave like what a glider does. That is no sign of stall.

I am think there are still possibilities of testing this airfoil concept. It would be interesting if there are photos showing stream line formation in smoke tunnel. Since there are drag and lift measurements. There should be potential developments on the KF Airfoil, my thinking.

Renold... take a look at how the air has attached itself to the rear end of the car and filled out the shape of the car. This vortex attachment makes the car move through the air more efficiently. That is why sports cars today have blunted rear ends instead of tapered. Thanks for your interest in the KF airfoil.

Dick Kline

[dickeroo]

Additions to this post.

I originally created the Kline-Fogleman airfoil from making a paper airplane. This happened over forty years ago. When I created the paper airplane it had the step on the bottom and flew extremely well. It would not stall and had great air penetration. Then, I tried the step on top. It flew even better, but needed a small amount of reflex. In wind tunnel tests, it showed that the step on top produced higher lift over drag ratios. Fogleman and I obtained a patent on this design, however, we were completely rejected by the experts. Their improper testing of the KF airfoil was a disaster. Plus, they never tried it on an actual aircraft, but instead did testing using conventional methods. This did not reveal the true properties because they weren't looking for them. In 1985, I wrote a book about my experiences called "The Ultimate Paper Airplane." Only now, because of the RC Groups experimentation have the true properties become a reality. There is so much more I could tell you, but this space does not permit. New ideas are never embraced by those with authority. It is too far outside their box. It also threatens their expertise.

To date, no negatives have shown up on the KF airfoil. Here is a brief list of the KF advantages: 1- The KF airfoil has a very wide speed range from very slow to very fast. 2- It has a much better Center of Gravity at 40% vs. 33% for conventional airfoils. 3- It has great control authority at all angles of attack. 4- It has better air penetration than conventional airfoils. 5- It has a higher wing loading than conventional airfoils with a very forgiving CG. 6- It is basically unstallable if properly balanced. 7- It flies as well right side up as upside down. 8- It has a very true tracking through the air which makes for a better photography platform. 9- It does not require reflex which adds to drag.

I hope I have been able to answer your questions to your satisfaction. Please let me know your experiences with the KF airfoil. It pleases me so much that you find it of interest.

The KF airfoil has some additional advantages that I forgot to mention in my previous post.

10- The first half of a conventional airfoil produces all the lift. The KF airfoil produces lift over the entire upper surface because the area behind the step is causing the air to rotate faster than the air underneath. So, the second half of the KF airfoil is producing lift as well. 11- The KF airfoil can handle very strong winds when conventional airfoils cannot. 12- Because of the KF step being a second layer, the wing is stronger for RC fliers and doesn't need additional support.

May you always have the perfect flight.

[loyn]

Like to find out what determine the "air foli" location, to be on top or below?

With the limited knowledge I dont really fully capture the concept of down ward air foil of the KF design ! How can it create a stable lift when it is upside down .... is that just like flying upside down all the time ? With the air flow much faster at the bottom of the wing ..... how can it create lift for stable flight.

By the way, any information about the shape and thickness of the KF design ? Is it only limited to constant chord and thickness ?

Thanks for sharing this is very educational discussion

[dickeroo]

You will have to become an explorer and experience the effects for yourself.

Like to find out what determine the "air foli" location, to be on top or below?

With the limited knowledge I dont really fully capture the concept of down ward air foil of the KF design ! How can it create a stable lift when it is upside down .... is that just like flying upside down all the time ? With the air flow much faster at the bottom of the wing ..... how can it create lift for stable flight.

By the way, any information about the shape and thickness of the KF design ? Is it only limited to constant chord and thickness ?

Thanks for sharing this is very educational discussion

The effects of the Kline-Fogleman airfoil have yet to be fully understood.
If you go to this thread, which is 80 pages long, you will see how knowledge about this airfoil developed. The KF airfoil works, but how is still somewhat of a mystery. Everyone who builds it correctly gets basically the same positive results, however. So far, no negative results have shown up.
Here is the site:

http://www.rcgroups.com/forums/showthread.php?t=558321

To see it actually perform for yourself, go to these sites. Notice how the plane flies upside down and the pilot has no trouble controlling it at all. It also flies very slowly without stalling or flies very fast as well.

http://www.youtube.com/user/Regal49

http://www.youtube.com/watch?v=_8vYlujb_HE

http://www.youtube.com/watch?v=WIgjTiUtiik

http://www.stenulson.net/rcflight/dancer1.mpg

http://www.stenulson.net/rcflight/slimbeag.htm

http://media.putfile.com/Funder-and-lughtning

The airfoil works whether it flies right side up or upside down. Only sophisticated wind tunnel testing can confirm what is actually happening.
There is still a great deal to be learned about how vortex attachment works.

You will have to experiment and see for yourself what works best for you. It will be an adventure that you will enjoy.

[loyn]

thanks for all the links and infromation , will build simple model with this wing to learn more from actual flying and building