horizonal stab/elevator rib stich

[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!