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Vertical Stabilizer Nose Rib Question

cwharris

Active Member
My first of many questions. Has anybody had any problems fitting the Vertical Stabilizer part number VS-705 Nose Rib to the skin profile? My nose rib seems to be a little fat towards the leading edge. I can?t seem to get the rib in place without pushing out the skins a good bit. I rounded the edges like the plans show but it seems to be fat where the joint in the rib is.
 
Try fluting the end of the rib on each side of the lightening hole. This will bring the flanges in to fit nicely.

Picture - rib clecoed in the skin makes optical illusion - it's the rib in the middle marked L2 :)
DCP_1176.JPG
 
Here is a picture of what I have. The fit looks a whole lot better then it did but still the fit is a little tight which is making the skins push out.
k2jora.jpg
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Fluting the end worked. I had to place a flute in the center as far back as I could. This pulled the width in just enough to make a nice fit. I?m happy now. Thanks for the advice.
 
picture size

I read this forum on my tablet. When the pictures get posted larger than recommended (800 x 600) it is very difficult to read. I have to constantly scroll or pinch.
 
Isn't one of the purposes of the ribs to give the skin the correct (designed) airfoil shape? And wouldn't fluting change this shape?

In this case (a vertical stab) it probably wouldn't make any big difference, but I don't think I'd try this on a wing or horiz.
 
Isn't one of the purposes of the ribs to give the skin the correct (designed) airfoil shape? And wouldn't fluting change this shape?

In this case (a vertical stab) it probably wouldn't make any big difference, but I don't think I'd try this on a wing or horiz.

It could have some effect (probably very slight) on the fit of the fiberglass empenage fairing later.
 
fluting just the ends?

I'm fitting these ribs right now. VS705 and VS706. I had to flute the end of VS706 slightly to fit it easily. After fluting it went in very well and looks good. I'm still not satisfied with the nose fit of VS705.

My question is did anyone flute the flanges of the ribs as called out in step 6? VS704, VS705, VS706 and VS707 all look really nice and it doesn't look like fluting is necessary. Step 6 says to do it as required. My newbie eye says it doesn't look like it's required, but then again, it may need recalibrating.

Jeff
 
Lay a flexible straight edge beside the row of holes and see if they are all aligned.
I think you will find that they are off slightly. A little bit of fluting will align them so they match with the straight line of holes in the skin.
 
As Scott said, I had to flute all three ribs to get the holes aligned with a straight edge. Just a few tweeks, mostly towards the ends. BTW, I also struggled with the fit of the VS 705, but eventually got it with the help of a fellow builder.
 
FYI, the reason the manual says "as needed" is because the amount of fluting required is variable depending on the location on the part.

The requirement for fluting will increase as the radius of the flange increases.

So the portion of the flange that has the most radius is the portion that will have to be fluted the most. If a part has a flange that transitions from curved to straight, the curved portion will require some fluting and the straight portion probably none.
 
You Rule

Thanks. That helped a lot. When I used my daughter's flexible ruler and laid it down on the rivet line I could see what you were talking about. I few flutes later and everything is good.


Lay a flexible straight edge beside the row of holes and see if they are all aligned.
I think you will find that they are off slightly. A little bit of fluting will align them so they match with the straight line of holes in the skin.
 
Vertical Stab skin over bent?

Excellent posts here, so valuable to a newbie like me.

Working on the vertical stab. Have the entire assembly cleco'd together for fit. The root rib was a bear to install. It appears that the VS skin might be over bent. The photo shows my fluted VS-705 root rib (tried to flute it multiple times, needed a longer fluting pliers I think) and it finally fit, but look at the right side of the skin. It is markedly concave about 1.5 inches from the leading edge. If I were to adjust the size of the rib to eliminate that bending, it would be significantly smaller, and not likely possible with just fluting alone.

Does this look OK or should I stop and seek help?

Link to photo: https://goo.gl/photos/gb4s1m7tfYGZ2cuH7

gb4s1m7tfYGZ2cuH7
 
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I say good.

Excellent posts here, so valuable to a newbie like me.

Working on the vertical stab. Have the entire assembly cleco'd together for fit. The root rib was a bear to install. It appears that the VS skin might be over bent. The photo shows my fluted VS-705 root rib (tried to flute it multiple times, needed a longer fluting pliers I think) and it finally fit, but look at the right side of the skin. It is markedly concave about 1.5 inches from the leading edge. If I were to adjust the size of the rib to eliminate that bending, it would be significantly smaller, and not likely possible with just fluting alone.

Does this look OK or should I stop and seek help?

Link to photo: https://goo.gl/photos/gb4s1m7tfYGZ2cuH7

gb4s1m7tfYGZ2cuH7

I'm no expert, but I think it looks ok. It appears the stab skin is just slightly "bulged" out from the rib fitting just a bit too tight. That skin is pretty thick though. That rib is definitely a little wide at the tip to fit the leading edge of the skins and difficult to fit. Some people fluted as you did, some trimmed, and some did both. I just trimmed the rib as much as could without "violating" the required edge distance for the #40 hole that gets match drilled from them skin. If yours fits now without too much force, I would leave it. If you trim now, there may be a gap between the skins and rib where you have your slight "bulge", and it could be difficult to close that gap when riveting later.
 
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I agree, it should be fine.

The empenage fairing interfaces with the vertical stab well above that point so the skin will be its natural shape where the fairing contacts
 
I radiused the front edge as called for and fluted the long flanges. Se pic.

Fit fine.
 

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