Bearhawk LSA rib stitching

[joe]

The plans aren't clear on where stitching is required, ie. Tail feathers, side formers ect. Anyone flown without rib stitching?

[Flygirl1]

The ONLY place we did not use rib stitching is on the lowest rib on the vertical and it has not been a problem. I might be wrong, but when you ask "Anyone flown without it", I'm thinking you might think it is difficult to do. It's not. In fact once you get the hang of it, it's kinda fun. ;-) We used the staggerwing stitch and though it does present itself on paper as difficult, it really isn't. Wendy Pemberton has a couple of excellent video's and a search will show you lots of options. As far as how to where, I would also suggest you get the polyfibor how to book. Lots of good info there. D.

[jaredyates]

This is a case where it is better to consult the directions for your covering system of choice, rather than the plans. I took following their directions very seriously, since a control surface without fabric might as well not be there.

[BTAZ]

I took my lead from the well documented Piper Cub requirements (http://thecubden.org/thecubden/paint...itch-placement)

The horizontal surfaces and the rudder is very straight forward. I stitched the upper ribs of the vertical stab full length. I taped but only stitched a couple on the trailing edge of the lower rib where the fabric actually touches the rib

[jaredyates]

The polyfiber manual addresses rib stitch spacing based on airspeed, so in that case Cub guidelines may not be compliant.

[BTAZ]

To add clarification, I used the Pacer vertical stab guidance in the Cub link for the vertical stabilizer with regards to which ribs to stitch and what didn't need to be done. In particular, the lowermost rib doesn't contact the fabric full length because of the fin offset. Research found opinions in the "Cub world" ranging from "Add stitches but don't pull the fabric tight to the rib" to "If Piper didn't see the need then I don't either".

The actual spacing/stitching for the rest was derived from the Stits manual. Note Piper used basically the same stitching pattern for J-3 through PA-20/22 which comfortably covers the LSA operating envelope(and IIRC matches the Stits recommendations)

[Collin Campbell]

I remember having this discussion back when I covered the Patrol. That bottom rib on the vertical stabilizer seemed to me like it would take a lot to pull it in to conformity with the profile of the rib, especially on the right side due to the fin offset. I was thinking of just leaving it without the stitches but someone mentioned that Bob would like it to be stitched to maintain the profile as low as possible for maximum effectiveness. So that's what I did... Collin