** Kline-Fogleman Airfoiled Flying Wing ** - Page 36 - RC Groups
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Apr 09, 2007, 09:56 AM
Will work for foam
wingnutt's Avatar
I have really become a fan of the addition of a slope behind the step. My current test design uses a step peak at 40% chord which slopes back to the wing surface at 50% chord. With a step height of 7.5% thickness (measured from peak of step to other wing surface) this yields a slope angle of about 60 degrees. From what I can see, all of the KF properties are still held, but with reduced drag. I guess this is no longer a KF as there is no longer a hard step. Another great benefit is that in most cases, a spar is no longer required if the step is left hollow as it creates somewhat of a ‘D-box’ leading edge.
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Apr 09, 2007, 10:23 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Spiderwire pull pull thread cables would lighten the rear end ... less to put on the front ... a couple of short pieces of Coffee stir straws for guides...
Apr 09, 2007, 10:26 AM
I'm not flying backwards!
Tony65x55's Avatar
Quote:
Originally Posted by Artemis999
If anyone could help me on this one:

I have a wing cut out. I used 2 30x20 sheets of Dollar Tree 3/16 foam board. I plan on using a layer of tape all over it to strengthen it up some. I'll cut out the spars tonite.

All they had at the hobby store was a slinger arf flaperon mixer. Hopefully this will do what I need. I have a JR sport that doesnt have mixing.

I also purchased a few different size props, and a parkzone 480 brushed, and a GWS EM400 brished motor.

My batteries are the 2/3 A type as used in the hobbyzone supercub. They are 7 cell 8.4v 1000 mah. The weight on these is 5.4 oz I believe. I have several of these so would like to use them if possible.

I plan on removing the paper on the foam board.

I also have several GWS Naro servos, wire, glue, and all that stuff.

Question: Can someone recommend a motor/prop combo that will work with what I have? My main concern is to use what I have. I'm not interested in brushless or lipos at this point.

Your stuff should work great. Start with the 400 for the weight.

Tony
Apr 09, 2007, 10:50 AM
I'm not flying backwards!
Tony65x55's Avatar
Man, you guys are going great guns on this stuff. It's getting hard to keep up with the responses.

Viking, the HLG sounds great.

Dritch, congrats on the maiden, sounds like you have a nice bird there.

Wingnutt, it sounds like the sloped step might have some real potential, maybe even in combination with the 90 degree step to thicken the wing chord without undue drag.

BTW, I refer to all these collective foils as Kline Fogelman Modified or KFm as none of them are like the original patent but share the same design principles as the original. Maybe when the day comes when we have a finalized blueprint of this airfoil we can change the name to something like the KFRCG airfoil. That's "Kline Fogelman RC Groups". Until that happy day, they are all KFm's.

Tony
Apr 09, 2007, 11:36 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Simple or complicated , they all seem to work !!!
Apr 09, 2007, 11:39 AM
Registered User
DRITCH's Avatar
Finall got my first cd motor in.

Building a pusher cat with a blunt nose pod and cf booms.

Pod virgin styro and tape about 4x4x20
wing newer fff 30" span 10" cord about 1.5 dihedral per wing.
kf foil at 50% on top. no spar, just wood glue.

7x5 apc DD

350 3cell and 1000 3cell --not sure which will work. Might end up using one for light and one for heavy if it works out ok.

ret control.

May add ailerons later. If it lives that long.

My goal is an aileron/aerobatic trainer that can really slow down if needed and can self right itself if you let go. Going with a pusher cat style cause I don't want the prop to ever touch the ground.
Apr 09, 2007, 12:03 PM
High Altitude Flyer
viking60's Avatar
Quote:
Originally Posted by wingnutt
I have really become a fan of the addition of a slope behind the step. My current test design uses a step peak at 40% chord which slopes back to the wing surface at 50% chord. With a step height of 7.5% thickness (measured from peak of step to other wing surface) this yields a slope angle of about 60 degrees. From what I can see, all of the KF properties are still held, but with reduced drag.
Wingnut,

Thanks for this report.

Reduced drag is GOOD!! - Especially when we're speaking of gliding performance on HLGs & DLGs. (The Beagles really love to thermal, too!)

I should be able to quickly & easily add a sloping filler piece behind my step to test - (although the step is back at 50% on this wing for now) - just tape it in place & fly. I'll post a report when I do get a chance to test-fly my wing without, & then with it.



VIKING
Apr 09, 2007, 12:20 PM
Will work for foam
wingnutt's Avatar
Viking - looking forward to hear how it turns out! keep us posted.
Apr 09, 2007, 12:48 PM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
V60 , would be really easy to do an elliptical dihedral on a KF airfoiled wing .... Just a little heat gun both pieces , then glue together... Simple !!!
Apr 09, 2007, 09:57 PM
Registered User

Experimental results


xxx
Last edited by Ballistic; Sep 25, 2010 at 06:19 PM.
Apr 09, 2007, 11:18 PM
High Altitude Flyer
viking60's Avatar
Friends,

Here's the progress photos on the Pod & Boom HLG fuselage; looks like it's going to come out around 6-1/4 to 6-3/8 ounces, using a 1-1/4 ounce Rx battery in the nose. That will result in a wing loading between 2.75 and 3 ounces per square foot, which should be light enough for this test!

More soon!

Wingnut,

When I get to the stage of adding in the angled filler for the test, I'll definitely post the flight report; I'm already expecting that it just HAS to help clean up the drag, & improve the glide efficiency.

GPW,

The eliptical wing tips may be enough to provide the desired stability; it'd look neat to do the gradual eliptical curve in more of the outboard ends of the wing. (I think I'd be inclined to keep the center ~60% flat, with a strong spar structure, and transition into the eliptical sweep from there.

VIKING
Apr 09, 2007, 11:46 PM
Impact Testing Specialist
drcrash's Avatar
Ballistic,

Could you say more about the conditions you were simulating? I'm wildly guessing 3D simulations and a rectangular, unswept wing with a barrier (fuselage) on one end and not the other... is that correct?
Apr 10, 2007, 05:56 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
V60... great idea!!!!!
Apr 10, 2007, 02:53 PM
Registered User
Quote:
Originally Posted by Tony65x55
No one has tried the KFm although the original KF was wind tunnel tested. NASA concluded it was unsuitable for their applications although other testing had variable results. Real wind tunnel tests would be nice, but very expensive to do it right. There has been some work done on step angles as Brucej reported above but there is a ton of room for experimentation. Let us know what you find out.

Tony
I built a wind tunnel and tested the airfoil with yarn tufts. The yarn stuck to the wing but at stall angle the yarn in the notch stayed but yarn not in the notch curled up on the leading edge. The model was about 12"x 6" and did not have the notch across the whole wing. Yarn near the notch also went into the notch and stayed on the airfoil at stall speed.
Apr 10, 2007, 05:50 PM
I'm not flying backwards!
Tony65x55's Avatar
Thanks Dick, good info. Ballistic, keep it coming man. We're all still trying to get a handle on it.

Tony


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