One of the members posted a new design flying wing today and mentioned it had the Kline-Fogleman airfoil. I did some research on this unique airfoil and came up with this.Here is a short article about the design: http://bfoamy.com/?page_id=664And here is a few variations of the design, presented as airfoil sections:
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I'm building up a long thin KFm3 but want a Hoerner curved tip. Any thoughts on how to step this down with the KFm3? The dimensions are 12 foot span by 13 inch cord. Input would be appreciated.
If the wing tip is cut at 45-degrees with a small radius at the bottom and a relatively sharp top corner, the air from the secondary flow travels around the rounded bottom but can’t go around the sharp top corner and is thus pushed outward.
The performance of the aircraft depends on the distance from the right to the left tip vortices (the effective wing span), and not the actual measured geometric span. Hoerner wing tips provide the largest effective span for a given geometric span or a given wing weight.
For those of you interested in the Kline Fogleman airfoil concept, you might want to check out this thread which discusses why people chose the airfoil they use. It is only four pages long and a number of people seem to prefer the KFm airfoils and they state the reasons why they use them.
Unlike the example from above the KFm3 airfoil of my flying wing is built without spars (except for the root section). The rigidity results from the overlapping foam sheets.
Have a look at the PDF plan for a cross-section of the wing.
I found the linked article interesting, but merely subjective - and note that an autopilot may be an excellent tool for evaluating wings empirically, since the results can be directly reduced to numbers. This would requite a ground link or data-logger of course.
Replies
If the wing tip is cut at 45-degrees with a small radius at the bottom and a relatively sharp top corner, the air from the secondary flow travels around the rounded bottom but can’t go around the sharp top corner and is thus pushed outward.
The performance of the aircraft depends on the distance from the right to the left tip vortices (the effective wing span), and not the actual measured geometric span. Hoerner wing tips provide the largest effective span for a given geometric span or a given wing weight.
http://www.rcgroups.com/forums/showthread.php?t=1051573
Have a look at the PDF plan for a cross-section of the wing.
Or the RCgroup thread
There's also a nice test video of 4 different KF airfoils on youtube (by RCpowers.com)