Rib Stitching Tail Surfaces

D

Dick Goff

New member
Hi All,
Doe anyone have the criteria, or info, necessary to determine the proper rib stitching for the tail surfaces on my 14-13-2. I don't mean the spacing. How much do you pull the fabric down towards the rib, at the leading edges. Do you pull the fabric all the way down to the rib with the first stitch ? I did before, but it looks wierd.
Dick N29TJ
 
Perhaps I don't quite understand the question,.... but the fabric should "already be in contact with the rib", i.e., the rib should be providing the airfoil shape to which the fabric forms it's self. You shouldn't have to pull the fabric to the rib. If you have a metal leading edge that is standing proud of the nose rib area then it hasn't been properly attached to the ribs. If you can push on the leading edge skin over a nose rib and feel any movement before the skin touches the rib then you have to reattach the skin down tight to the nose ribs.

If this isn't what you were talking about, then please forgive me.

If that IS the situation, then the airfoil is a different shape from what it should be, (including the flight characteristics) and you're now a test pilot!

If this has all been totally off base, then post a reply with some specific details, and we'll try again. I'll try not to lead you too far astray!!

Rareblair
 
Hi Rareblair, and others,
I'm sorry for the confusion. I should have been more specific and stated "The Moveable Tail Surfaces." The vertical fin and horizontal stabilisers are O.K. They have ribs that touch the fabric surfaces. It is the elevators and rudder that pose a problem.
This is due to the construction method utilized by Bellanca. The leading edge of the elevators is constructed of an oval shaped tube,1 5/16" high. The elevator ribs are a single piece of 3/8" tubing welded on the centerline of the leading edge and flattened to 3/16" at the trailing edge to fair in the trailing edge. When wrapping the fabric from the trailing edge, around the leading edge and back to the trailing edge, this leaves a gap of approx. 1/2" from the rib (tube) surface to the fabrc at the leading edge. The rudder is the same, but to a lesser extent.
Should the first rib stitch pull the fabric down to the rib, immediately behind the leading edge (1/2)? Or try to fair it in to the rib which would leave a few rib stitches lose. That was my question. Dick N29TJ
 
Dick,
Okay, now I understand. After reading your repsonse, I went out to the airport and looked at my friends' airplane. Let's take the fourth rib in from the tip as an example. If you hook your tape measure on the front spar... the rib stitches are located at...1", 3", 5", 7", 8", 9", etc.. The first rib stitch "in complete contact with the rib" is the stitch at 5" aft of the leading edge (spar). This was true for every rib in the elevator, i.e., the first stitch aft of the spar to bring the fabric in complete contact with the rib is located at 5" back from the spar. All other stiches from there on back are, of course, tight to the rib.

The stitches at 3" and 1" are only slightly "compressing" the fabric. There are no obvious dips or puckers in the fabric at the stitch.

It looks like you might want to start your rib stitching at the 'trailing edge' and work forward, bringing the fabric down tight to the rib with every stitch up to and including the stitch at the 5" mark. From there on forward, just bring the stitches tight enough to eliminate any possible 'flutter' in the fabric.

The spacing of the stitches is interesting. They are spaced every other inch from the 1" mark back to the 7" mark, then at one inch increments from there on back to the trailing edge. (Typical of all the ribs except the tip rib).

Another interesting point is that there was a 'gap seal' piece of fabric that went from the top side of the horizontal stab through the gap to the bottom side of the elevator.

Hope all this makes sense!
Rareblair
 
Hi Rareblair,
I want you to know that I deeply appreciate the time , trouble, and effort you have put forth to answer my questions. I agree with you, I will start at the trailing edge and stitch forward.
Once again, thank you so very much. Dick Goff N29TJ
 
Dick,
My pleasure...after all, I learned something new, too. (I consider the day 'wasted' if I haven't learned anything...so yesterday was a good day.)

Good luck with your project!!

Clear Skies,
Rareblair
 
My problem is as I work forward on the control surfaces, I'm having problems pulling the seine knot tight enough to to pull the knot together, but not so tight as to pull the fabric down to the rib. Maybe if I used round lacing chord instead of trying to use the flat stuff :?:
Any advice would be most helpful.
Yeah, I stopped on the fuselage until I decide to redo it or not. :?
 
You must log in or register to reply here.
Back
Top