horizonal stab/elevator rib stich

[Flybyjim]

Has anyone stitched the ribs in the stabilizer and elevator?

[DesertFox4]

I think Mike did on his Gold Lindy award winning Rotec powered Kitfox.

[Flybyjim]

Thanks, I am guessing most folks do not stitch these only the wing ribs?

[DesertFox4]

Most do not.
Not needed using the PolyFiber covering system. Probably not either for the Stewart’s system. Not at all sure what the Ortex system suggests.
Those that stitch may do so for piece of mind or the retro look of stitching on those surfaces. Certainly doesn’t hurt a thing to stitch them.

[David47]

I didn't stitch mine. Considered it but decided against it because there's very little surface contact of the rib with the fabric and I was concerned about the closeness of holes either side of the rib and the potential for fabric tear through. I was just extra generous with the Poly brush.

[N213RV]

I think Mike did on his Gold Lindy award winning Rotec powered Kitfox.

Great memory Steve! I did stitch all my flying surfaces. I like the looks of it, and it of course it is safer (not that those who have not stitched have had any problems).

I can send pictures if interested.

Thanks!

[jiott]

Mike, how did you address the concern David had with the 1/8" wide ribs and the closeness of the stitch holes? Also how would you use the reinforcing tape on such a narrow rib? You must have added cap strips to all those ribs?

[t j]

Make some 1/4 inch reinforcing tape. Cut some lengths of 1/2 inch tape to length to cover the elevator ribs. Stick them on a piece of glass. Use a straight edge to cut it down the center line with a razor blade. Peel it off the glass and stick it on the cover over the elevator ribs.

[Cherrybark]

Didn't rib stitch these ribs. Chiming in to say a rotary cutter, available in the crafts section of Wally World or any fabric store, is a great tool to cut something like the tapes. Relatively cheap with replaceable blades. And, of course, Amazon provides a nice picture and description.

https://www.amazon.com/Fiskars-Contour-Rotary-Cutter-195210-1001/dp/B000B7M8WU/ref=sr_1_1?ie=UTF8&qid=1519689390&sr=8-1&keywords=rotary+cutter

[N213RV]

Mike, how did you address the concern David had with the 1/8" wide ribs and the closeness of the stitch holes? Also how would you use the reinforcing tape on such a narrow rib? You must have added cap strips to all those ribs?

Aircraft Spruce sells 1/4” reinforcement tape, I bought a roll or two of it for all the 1/8” ribs. I then used 1” trim tapes over it. I didn’t have an issue with holes tearing from the rib stitching. Even if there were some small holes, the trim tapes cover them. Pictures attached.

[N213RV]

I found a couple in process pictures. There does appear to be some small holes at some of the rib stitches, but again, no issues with the trim tapes covering them. I am beyond pleased with the final results. I had monocoated many RC planes, but this was my first polyfiber work.

[Flybyjim]

I have to assume if you did stitch these ribs you first drill holes in the support braces that were glued to the ribs to keep them from warping. Correct?

[N213RV]

I have to assume if you did stitch these ribs you first drill holes in the support braces that were glued to the ribs to keep them from warping. Correct?

That is correct, I identified the spacing and predrilled the support braces and ran the lacing through these holes. Sorry I forgot to mention this earlier.

[HighWing]

I rib stitched both but largely because of a Mod I made on the rudder. The top three ribs I used were made of quarter inch foam laminated on both sides with a layer of glass with sanded micro at the edges to add a smooth surface there. On the rudder, the lower two ribs were made from pairs of carbon fiber tubes fastened fore and aft with Hysol and attached together mid span with a short length of steel cable glued across the gap between the two tubes with Hysol. This was to see if changing the airfoil of these two ribs would serve as rudder trim. The rib lacing was largely to keep the fabric close to the rib surfaces as the airfoil changed. The vertical and horizontal stabilizers and elevator was laced as well for continuity.

Yes, the changing airfoil does serve as a means of trimming the rudder.

[Ronin]

I rib stitched both but largely because of a Mod I made on the rudder. The top three ribs I used were made of quarter inch foam laminated on both sides with a layer of glass with sanded micro at the edges to add a smooth surface there. On the rudder, the lower two ribs were made from pairs of carbon fiber tubes fastened fore and aft with Hysol and attached together mid span with a short length of steel cable glued across the gap between the two tubes with Hysol. This was to see if changing the airfoil of these two ribs would serve as rudder trim. The rib lacing was largely to keep the fabric close to the rib surfaces as the airfoil changed. The vertical and horizontal stabilizers and elevator was laced as well for continuity.

Yes, the changing airfoil does serve as a means of trimming the rudder.
More closeup pictures please?

[Flybyjim]

This is a very interesting concept of a trim for the rudder.

[jrevens]

...
Yes, the changing airfoil does serve as a means of trimming the rudder.


That is so innovative, and well conceived, Lowell! As I've said before, you are a true "experimenter" and craftsman in the truest sense!

It looks like the 2 "cams" rotate & push against & the carbon fiber "ribs", warping them out on one side, or the other. Is that correct? Whatever is happening, it is a very cool idea!

[David47]

Seeing the comments here, it looks like this may be feasible to do. I’ve fully shrunk the horizontal stab and put the first coat of Polly Brush on but I might give it a try even at this stage.

[aviator79]

That is so innovative, and well conceived, Lowell! As I've said before, you are a true "experimenter" and craftsman in the truest sense!

There's a certain irony in wing warping being considered an experimental innovation 115 years after the Wright Brothers used it to control their flyer. I don't disagree that this is a very innovative way to trim the rudder, and it's twice as cool that it touches the tips of aviation's roots.

[Dave S]

The neat thing about Lowell's rudder trim is there is a complete lack of stuff on the outside which eliminates any unnecessary drag. Simply changes the crown on the rudder to provide a little lift to the side.

As Always, Lowell's creative engineering, use of materials and excellent craftsmanship serves as a good example for experimental aviation.

On a sidebar, I have a friend back here in "Minnesnowta" who flies an ancient Fairchild highwing with the upside down inline engine. When he went to recover the machine, he became aware of the fact that there was a small grommet hole in the middle of the rudder with a little screw inside. Puzzled about it for the longest time and ..... you guessed it!

[HighWing]

The neat thing about Lowell's rudder trim is there is a complete lack of stuff on the outside which eliminates any unnecessary drag. Simply changes the crown on the rudder to provide a little lift to the side.

On a sidebar, I have a friend back here in "Minnesnowta" who flies an ancient Fairchild highwing with the upside down inline engine. When he went to recover the machine, he became aware of the fact that there was a small grommet hole in the middle of the rudder with a little screw inside. Puzzled about it for the longest time and ..... you guessed it!

I find this comment fantastic - actually beyond that. After my Phase 1 I decided it was time to see if the system worked. It did and then the "small grommet hole" came to mind. Because, as is generally the case with the rudder trim tab, once it is set, you sort of forget it. That was my experience with the rather "heavy" servo becoming instantly redundant. The thought came to mind that if I were to do it again, it would have a socket head cap screw behind a small hole so that an allen wrench could be used for the trim adjustment.

More Pictures: Much of the hardware geometry was needed to reduce the almost one inch throw of the servo. A screw adjustment could reduce a lot of that, making the system even lighter. The picture showing the top most cam also shows the short length of cable used to hold the two rib tubes together. The last picture shows the light weight aluminum "U" channel that was glued onto the outer surfaces of the carbon fiber ribs to give the flat surface needed for the conventional look after rib lacing.