Sign in to follow this  
Followers 0

Rib Lacing with Beech Staggerwing Knot

15 posts in this topic

Posted (edited)

Maybe it was too late in the evening or I was tired, but I am having some difficulty grasping the finer points of rib lacing with this 'simplified' knot. The running stitches are not a problem and go pretty smoothly, but the start and stop knots are frustrating me. Particularly the stop knot as I can't find a diagram to print out. Supposedly, the Stewarts System Fabric Finishing Manual has instructional diagrams, but I haven't found them in the D/L'able manual from their website. As reference, I have used the 2-part YouTube videos from Wendy Pemberton and the attached diagram. The diagram, however, doesn't show the start/stop knots and the video is often zoomed in so close you kind of have to go by the commentary alone without benefit of a good visual. Does anyone have a source for a diagram of the stop knot used in the Pemberton video? To make it real interesting, Stewarts and Pemberton techniques also use different start knot methods as well. Plus, Stewarts YouTube video says to turn the first loop clockwise, while the diagram shows counter-clockwise? Fun stuff, this lacing shiet. :huh:

staggerwingknot.jpg

Edited by dholly

Share this post


Link to post
Share on other sites

Posted

Never tried this type of stiching, always used what's shown in the poly fiber book.  It's actually fairly easy after you get the hang of it.  Looking at this knot, I would wonder if it will tighten up, but I suppose it must.  Can't you do the same knot on the end and add a couple of more half hitches?  That's what you do with the poly fiber knot.    JImChuk

1 person likes this

Share this post


Link to post
Share on other sites

Posted (edited)

Doug,  Have you looked at AC43-13?  EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted

Looks like this knot is easier to tie than the polyfiber "modified seine hitch".  I did the same as Jim, just added a couple half hitches to finish the knot.  At the end of the day, the likely hood of any knot including just a couple of half hitches turning loose are so remote that Vegas probly wouldn't give you odds on it.  If I can pull a 80' long tree with a couple half hitches, I kind of doubt you can get them to turn loose on rib stitching, its just sliding them to hide them that would be the issue.

 

:BC:

 

Share this post


Link to post
Share on other sites

Posted

Ed - the Hidden Beech Staggerwing Knot is not in 43.13, but it is FAA ok'd for most aircraft due to the high Beech Vne. I like it because the running stitches are a bunch quicker than the modified seine. I figured out what I was doing wrong with the start knot, but the hidden stop knot is still a bit of a PITA. I don't think the knot lends itself to the half hitch ending and I do want that last knot inside the wing. It doesn't help that my wing orientation is an upside down mirror image of the help video. :blink:

Share this post


Link to post
Share on other sites

Posted

Doug,  I'm not sure why you can't end up with the knot inside the wing if you do a couple of half hitches.  On my last stich, I have some string left after that last knot.  I hold that end of string in one hand, push the back of the needle back down inside the last hole, and pull the end of the string while pushing on the needle.  That rolls the ribstich loop around to where the knot is inside the wing.  Cut the string off about 1" from the knot, push in some more on the needle and the loose end ends up inside the wing.  Hope I explained that well enough.  JImChuk

Share this post


Link to post
Share on other sites

Posted

Jim, I suspect you assume the finish knot leaves only one tail. Actually, you are left with one tail and one loop but I figured it all out with a fresh look this am. After finishing one wing, all I gotta say is there is no freakin way the fabric is coming off that wing. Seems like 2-1/2" lace spacing is a whole lot of overkill!

Share this post


Link to post
Share on other sites

Posted (edited)

Jim, I suspect you assume the finish knot leaves only one tail. Actually, you are left with one tail and one loop but I figured it all out with a fresh look this am. After finishing one wing, all I gotta say is there is no freakin way the fabric is coming off that wing. Seems like 2-1/2" lace spacing is a whole lot of overkill!

Doug, I totally agree with you - When the rules were written they probably used hemp or cotton cord to lace cotton fabric -

But if 3 1/2" spacing cant hold the fabric on in the slipstream, then how would 2 1/2" spacing hold it?  EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted

Not argueing with you Doug, but maybe I'm not understanding this.  Looking at the knots in your first picture.  In the # 2 position, a half hitch is used to lock the loop.  I'm thinking if you use one or two more half hitches, the knot doesn't get fatter, just longer.  Not sure why it can't be buried by rolling the loop around like I suggested if it was the last knot in that rib.  Maybe I should go try it before I comment.  ;-)  I think I used 3" spacing on the Kitfox and Avid wings I've done.  Mostly cause it worked out with an even look getting around the rear spar.  I've flown many hundreds of hours in a number of Avids and Kitfoxes that weren't stiched at all so at least on those planes it didn't matter what the spacing would have been.  If you don't have a wide cap strip, of course things will be different.  JImChuk

Share this post


Link to post
Share on other sites

Posted

2 1/2" spacing seems like way over kill.  I cant remember off the top of my head, but I think mine was 4 or 5" spacing.

Share this post


Link to post
Share on other sites

Posted

I need to use the 2-1/2" lace spacing per the chart in the PolyFiber manual according to the A&P. That sure is a lot of laces, but since I'm not gluing fabric to the ribs like Avid/KF, I'm just fine with going by the book. That Staggerwing knot diagram only shows the running stitch but not the start and stop knots. Those are in the videos I mentioned. I understand any one line can terminate with a half hitch and be rolled under, but the stop knot and commentary on the video had me confused with the 3 lines. Took me a bit but it's all good now. Except my fingers took a beating, think I'll wear some old fingerless leather riding gloves for wing #2. :)

Share this post


Link to post
Share on other sites

Posted

Yep,that is a must have, have that on the iPad for quick reference. The spacing for my plane according to the chart is 2-1/2" in the prop wash area and 3-1/2" elsewhere. After voicing my concerns about not gluing the fabric to my aluminum ribs (i.e. Only mechanical attachment of fabric in my case are the laces), A&P said to use 2-1/2" for the whole wing if it made me feel better. It did, and layed out better with the internal structure than the other staggered spacing. In this instance the cost and weight penalty is so negligible, basically it just translates into a little more time, so that's what I did. Fingers hurt now but I'll have a warm and fuzzy feeling when flying.

1 person likes this

Share this post


Link to post
Share on other sites

Posted (edited)

Seeing that I hope to be doing some rib stitching this winter, I've appreciated this post. And Ed's reference to AC43-13 caused me to search it out. Thought other newbies might find this link useful:

https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_airframe_handbook/media/ama_Ch03.pdf

Rob, Thanks so much for posting this.  I usually don't click on AC43-13 links because I have the book - I am glad I looked at this AMT manual because it is so much better and easier to understand than my old AMT manuals or AC43 book.   It tells a lot about the different systems - Stewarts and Superflight 7 were not available when I went to AMT school.      Good Post and link, for All to read.   EDMO

Edited by EDMO

Share this post


Link to post
Share on other sites

Posted

Got ya, I didn't realize you were working on a bird that the fabric was not glued down.  Make sense to me now!

 

:BC:

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0