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My KFM Flying Wing

basslord1124

Well-known member
#1
Figured to go ahead and share my experience with the KFM flying wing.This was a design by @Hai-Lee found on this thread here:

https://forum.flitetest.com/index.php?threads/collaborators-build-1-800-mm-kfm-flying-wing.54085/

Here are some other related threads/posts:

https://forum.flitetest.com/index.php?threads/my-kfm-wing-build.56868/
https://forum.flitetest.com/index.p...y-journey-the-diary.58013/page-25#post-489345

I have more or less begun my build of the wing. Like others, had to shrink the plans down some to fit on standard dollar tree foamboard. I shrunk mine down to 95% and it was just barely enough. This is my first attempt at a flying wing. I've always thought they were neat but looked intimidating as I could see myself crashing everytime I launched it. @Hai-Lee swears by these wings though so that's assurance enough for me. I have the elevon layer and middle layer currently in the glued/drying phase as you see here:

Kfm wing1.jpg


I added some additional weight after I took this picture. I also added a metal rod to keep it strong on the bottom layer. Not sure if it really will be needed, but figured a little bit of strength can't hurt. I glued the middle layer on using Titebond woodglue and also removed all paper from the middle layer.

As for gear for the wing, I'm going to strip most of the electronics gear off my crashed FT Long EZ. 2 x 9g servos, receiver, and 30A ESC. I've got a spare 2300KV motor that I am going to use...and probably either a 5" or 6" prop.

I'll be updating this thread with build progress and eventually adding some flight experience as well. :)
 
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mayan

Well-known member
#2
This wing is strong my friends! Just yesterday I crashed it multiple times into the ground and it came out ok, just dust it off and re launch. One time I even had to pull it out of the ground because it decided to find a hold of the ground like Arthur’s sword in the stone :).
 

Captain Video

Well-known member
#3
I have wanted to build one of these. My boys fly Mini arrows and Goblins. Small and fast. The KFM wing looks like it might be pretty stable. Stable and slow, my favorite kind of wing. They can also be built very sturdy as well too. Perhaps a candidate for FFOH 20 combat.
 

basslord1124

Well-known member
#4
A little bit of an update to the KFM Wing....

kfm wing w servo.jpg


Servos are installed, and motor/ESC are about to installed next. I am using one of these motors and ESCs

2300kv motors escs.jpg


These motors and ESCs have quite the story. First off it is 2 x 30A GForce ESCs and 2 x 2300KV brushless motors. The motors are basically a clone of the Emax red bottoms. I used the pair in my FT Super Bee which ended up crashing into the woods at our RC field and went through rain, snow, wind, etc. They were recovered about 6-8 months later. I then later used the pair in a homemade foamboard differential thrust snow cruiser which didn't quite live up to my expectations. It was a decent attempt though. Well now, I am going to use 1 set in the KFM wing...and running either 5" or 6" prop. They are both capable of up to 4S power. The only maintenance I had to do was add some shrink tubing to the motor wires as the brush really did a number on them. I think I got both sets of them super cheap on ValueHobby.
 

basslord1124

Well-known member
#6
Will do @mayan . :) I believe it is pretty strong just by the feel of it.

Made a little bit more progress yesterday on the KFM. Ran into a snag that sort of slowed down my momentum. The servos/linkages were all taken from my crashed Long EZ. I able to loosen one of the linkage stoppers and get the control horn installed...BUT the other one proved to be a problem child. The set screw on the other linkage stopper got stripped or something and I was unable to loosen it up to move the pushrod so I could install the control horn. So had to replace a linkage stopper so I could get it to cooperate. All is good now, just need to center the control surfaces and tighten down the pushrods. I also got the motor installed.

kfm-motor.jpg
 

mayan

Well-known member
#8
@basslord1124 I think you need a wake up call on this thread and project. Have you maidened your KFM Wing yet? Did I acdiedently miss it? Any how here is a video I did flying a 3mm FB KFM wing flying off an F Pack motor, 20A ESC, 2x8g servos, a 6x4 prop and balancing off a 1000mah 3S battery. Hope you enjoy the video and it gets you to finish this project :).

 

basslord1124

Well-known member
#9
@basslord1124 I think you need a wake up call on this thread and project. Have you maidened your KFM Wing yet? Did I acdiedently miss it? Any how here is a video I did flying a 3mm FB KFM wing flying off an F Pack motor, 20A ESC, 2x8g servos, a 6x4 prop and balancing off a 1000mah 3S battery. Hope you enjoy the video and it gets you to finish this project :).

Yes I do, thanks so much for my wake up call! :) Amazing how life and things can just suck the time away...of course our little house issue took a lot out of me too. I have not maidened the KFM so nothing has been missed. My specs are almost exactly like yours actually...although I may be trying the maiden on a 5" prop.

It seems there for a while I was focused moreso on the Edge and then onto the Spitfire. My checklist of things to complete on the KFM is soooo small I should just go ahead and wrap it up. Things are returning back to normal, so I'll see if I can finish up things like the KFM wing and get a maiden flight and/or crash out of her. ;) Weather may be getting colder, but I'm still going to try and fly some.
 

BATTLEAXE

Well-known member
#10
Yes I do, thanks so much for my wake up call! :) Amazing how life and things can just suck the time away...of course our little house issue took a lot out of me too. I have not maidened the KFM so nothing has been missed. My specs are almost exactly like yours actually...although I may be trying the maiden on a 5" prop.

It seems there for a while I was focused moreso on the Edge and then onto the Spitfire. My checklist of things to complete on the KFM is soooo small I should just go ahead and wrap it up. Things are returning back to normal, so I'll see if I can finish up things like the KFM wing and get a maiden flight and/or crash out of her. ;) Weather may be getting colder, but I'm still going to try and fly some.
What is the wingspan, 30"?
 

basslord1124

Well-known member
#11
Yeah once resized its around 30".

Well I got most of the finishing touches done to the KFM Wing. I'm hoping and thinking I got the balance right. The only thing I need to do is add a little color for orientation and charge my battery.
 

basslord1124

Well-known member
#14
Been a little bit since my last update on this, but finishing touches have been done. Radio has been programmed, battery is charged, and I slapped a little bit of color (blue packing tape) on it for orientation help. Aiming for a maiden tomorrow on my lunch break. Weather will be a cool 45 degrees with about 5-6 mph winds.

Not really nervous or anything as I already feel it's a pretty tough wing and doesn't take much to build. I'm not even worried about launching it. My only concern is making sure I got the balance/CG right. We shall see how it goes. ;)
 

BATTLEAXE

Well-known member
#16
Been a little bit since my last update on this, but finishing touches have been done. Radio has been programmed, battery is charged, and I slapped a little bit of color (blue packing tape) on it for orientation help. Aiming for a maiden tomorrow on my lunch break. Weather will be a cool 45 degrees with about 5-6 mph winds.

Not really nervous or anything as I already feel it's a pretty tough wing and doesn't take much to build. I'm not even worried about launching it. My only concern is making sure I got the balance/CG right. We shall see how it goes. ;)
It's been awhile bud, busy Christmas?