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KFm-6 Wing

#1
Weather is still crud, so thought I'd mess around with a wing. Wanted to fit the entire width on a sheet of DTFB, so wingspan is 750mm. That takes about 0.25" off of either side of the FB to get a clean edge. Thought about designs a bit, looked at other pics, modified some other plans to fit the size I wanted. Building this as a KFm-6 wing, so who knows how well it will work. Probably better off with a KFm-4, but any dumb thing is better when you overdo it, right? Started laying out the plans and cutting.

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Gluing up the first layers. Pretty much all Gorilla Clear on this build. Some of the later sections of electronics housings are Gorilla hot glue.

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And more layers, you get the idea.

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Finally 5 layers, and I used the technique from @BATTLEAXE to iron down the edges. Bottom leading edge ironed here, top still standard cut. Mock up of the 3D printed motor mount.

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Tweaked the pod drawings from FT for their Mighty Mini Arrow to make a two-step housing for camera and electronics. The 600mW VTX stays on the outside for cooling. Pod is cut and inset into the top layer of foam. Also, 9g servos and 3D printed servo horns. I print mostly in PLA, but I coat the finished part in Gorilla Clear to help with strength, delamination, etc.

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Motor mount holds the 2205 2300KV motor and 20A ESC. Inside the pod lives the F411-Wing, FS-iA6B receiver (iBus), Hawkeye Firefly Split 4K camera, and the battery. GPS module not yet pictured, but it should arrive today.

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Belly shot for those interested. Still need to add the wingtip stabilizers, add some tape reinforcement on the LE and belly protection, color for identification, etc.

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Figure9

Well-known member
#2
I‘m interested in using some of the larger FT plans as a downsized pattern so wings, or perhaps whatever aspect has the longest end to end dimension, can be cut from a single sheet of DTFB. Hopefully the concept might provide a plan that easily adapt to smaller printers that use 8.5x11 standard letter sized paper. Smaller projects are easier to build on a limited space bench. Well done with this resizing, thanks for posting it.
 
#3
I‘m interested in using some of the larger FT plans as a downsized pattern so wings, or perhaps whatever aspect has the longest end to end dimension, can be cut from a single sheet of DTFB. Hopefully the concept might provide a plan that easily adapt to smaller printers that use 8.5x11 standard letter sized paper. Smaller projects are easier to build on a limited space bench. Well done with this resizing, thanks for posting it.
Thank you! FYI, I'm simply using open source Inkscape to edit, modify, and create plans. From there, I export the plans to PDF format. Opened in Adobe Reader, simply print in poster format with cut lines enabled. There may be better and easier ways, but it's what I've managed to figure out for myself.
 

Figure9

Well-known member
#4
Thank you! FYI, I'm simply using open source Inkscape to edit, modify, and create plans. From there, I export the plans to PDF format. Opened in Adobe Reader, simply print in poster format with cut lines enabled. There may be better and easier ways, but it's what I've managed to figure out for myself.
I like it because it gets away from the tile concept using the 8.5x11 printer so I’ll keep that in mind. Tiles are worth the trouble if commercial printing or large format printers cause unwanted expense or trouble. The FT business plan seems to lean toward the ‘Anybody can do it’ format by using common products, tools & appliances, I like that too. Figure9
 
#7
Very nice. Its very similar in size and build to one of my planes. Mine is a thick kfm4.
Kfm wings can fly super smooth.
I look forward to a flight video. Your build looks nice and clean.
Here is a link to my similar plane.
https://forum.flitetest.com/index.php?threads/club-racer-wing.60576/
Thanks for sharing! Looks very similar in size, and the video is very smooth. I was aiming for smooth, but with the extra bottom layers, I may have pushed drag too far, at the expense of shortened flight times. Maybe I can squeeze a 2200 in there?
 
#9
My wing is 5 layers thick. At the power to weight and speeds we are usually flying at low drag is not critical to a good flying foamy.
If your goal is efficiency or speed then aerodynamics are way more important.
Thick flying wings can be super smooth and have high lift with very gentle stalls.

I usually design with a goal in mind. It could related to a flight characteristics or construction related.
My guess is if you get the cg and thrust line right your wing will fly great.
My only concern from what I can see is how close the last kfm step is to the control surface. If its to close control gets jerky and unpredictable. The vortex that forms after the step messes up the effect of the elavons.
Best to try it and see how it goes