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Help! Kf Wing Dimensions

#1
I'm working up a slightly modified FT Long EZ. I want to use a KFm-2 wing to give it a little more lift than the plank wing. The KFm-2 description calls for making the step 9% thickness at 50% Chord. Question is; 50% of the wing alone or 50% including the Aileron? The step looks kind of short to me but I've never used one before so I thought I'd ask.

I also think the fuselage is a little pudgy so I'm reducing the profile to the prototypes vertical dimensions, but that's only about a half inch overall.

If you look close you can see that a lot of the paper is delaminating, especially in the corners and thin areas. I've never had foam board come apart so easily, is this common ?
KFm- 2 Wing #1 end.jpg KFm-2 Wing #1 Whole .jpg KFm-2 Wing #1.jpg

Thanks,
Dave
 

Merv

Well-known member
#2
.....Question is; 50% of the wing alone or 50% including the Aileron? ......you can see that a lot of the paper is delaminating...,is this common?
Yes the 50% includes the ailerons. The Kf is very forgiving, what you have will work.

I cover my planes with colored pack tape, the tape solves this problem for me. On the rare occasion I paint, I will glue the down the edges and any lifted paper.
 
#3
Thank you
Yes the 50% includes the ailerons. The Kf is very forgiving, what you have will work.

I cover my planes with colored pack tape, the tape solves this problem for me. On the rare occasion I paint, I will glue the down the edges and any lifted paper.
Thank you
I have used the packing tape on both of my previous builds, but I have been using it over the paper. If I remove the paper and cover with tape will it have the same structural strength. I’m pretty sure all the paper is going to fall off if I don’t remove it. I don’t mind making another wing, it’s pretty quick.
 

BATTLEAXE

Well-known member
#4
Thank you


Thank you
I have used the packing tape on both of my previous builds, but I have been using it over the paper. If I remove the paper and cover with tape will it have the same structural strength. I’m pretty sure all the paper is going to fall off if I don’t remove it. I don’t mind making another wing, it’s pretty quick.
There is a solution to your edges delaminating using a cheap household iron, I have a video on it, plus there are a bunch of other tips. If this video helps, check out the rest of the channel, like and subscribe would be much appreciated. Here is the link
 

Merv

Well-known member
#5
...If I remove the paper and cover with tape will it have the same structural strength. I’m pretty sure all the paper is going to fall off if I don’t remove it....
I think the answer is Yes, tape alone has the same or similar strength as paper. I have not tried removing the paper and using only tape. Here is a video of others doing that.

Regarding the paper coming off, you could always glue it back on. Some make "skins". They will remove the old paper, print whatever paint scheme they want & glue new paper back on the raw foam. Then use the skin to cut out a plane. I think they use a thinned white glue for this.

 
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#6
There is a solution to your edges delaminating using a cheap household iron, I have a video on it, plus there are a bunch of other tips. If this video helps, check out the rest of the channel, like and subscribe would be much appreciated. Here is the link
I watched your video. Looks like a good process. I will be giving it a try. Unfortunately my problem is much more pervasive than just the edges. One whole side of 4 sheets has failed on me so far. I don't think ironing the whole sheet will help. : ) I really do like the process though, I like the look of the rolled edges.
Thanks
Dave
 
#7
I think the answer is Yes, tape alone has the same or similar strength as paper. I have not tried removing the paper and using only tape. Here is a video of others doing that.

Regarding the paper coming off, you could always glue it back on. Some make "skins". They will remove the old paper, print whatever paint scheme they want & glue new paper back on the raw foam. Then use the skin to cut out a plane. I think they use a thinned white glue for this.

Thanks, I watched the Video and went ahead and made up one wing with just the tape. It seems strong enough but it is going to be easily damaged. It's not as tough a skin as the paper or paper and tape. It will fly well as its lighter but hanger rash will be a problem. I'm going to finish the build (Blunt Nose Versa Wing) and see how it goes. I'm pretty sure I will just make a new Long EZ once I find some petter foam board.
Thanks Again
Dave