Skin stiffeners

[Frank]

What is the current status of skin stiffeners on all kit models and LSA in particular?
One builder recently received an LSA kit with skin stiffeners.
Another builder received a kit a couple of years ago which did not.
Bottom line for me: is there a drawing available in case I want to include these on my scratch-build project?

[arborite]

I received my LSA kit in September. can you explain what you mean by skin stiffeners? My wings are still packed up, but i can check my fuselage parts.

[Bcone1381]

http://bearhawksafety.com/Patrol/february2020.html

https://bearhawk.tips/4247

In 2020 Bob added wing skin stiffeners to the Patrol's wing design. Its documented at the above references. I did not know and could not find these stiffeners being applied to the LSA in the change notices. The Modle B first came out in 2021, so I suspect the drawings incorporate the 2020 Patrol stiffeners. Maybe stiffeners are on the LSA wing due to a production tooling economies thing. I like the stiffeners.

[Frank]

In addition to the Patrol nose skin stiffener, Mark Goldberg describes two aft of the main spar:
"FYI - Bob has had us do a running change on the upper wing skin at the kit factory. The same kind of channel that runs span wise that Bob had us place in front of the main spar - we are now placing two channels running span wise aft of the main spar. At about 10 & 20 inches aft of the main spar. According to Bob - there are no structural issues as it was. Just a desire to clean up the airflow a little and theoretically maybe make another MPH or two. It does stiffen up that upper skin. Mark"

https://bearhawkforums.com/forum/bearhawk-general-discussion-news/67123-wing-skin-thickness

So there are three skin stiffeners possible. Apparently on all kit models? I'm not entirely sure.

[Frank]

With grateful acknowledgement to other builders and their helpful photos, here's one LSA kit wing with stiffeners and another wing without. I'm wondering if the LSA kits are coming out with all three stiffeners. I might or might not want to add that feature to my project.

[Tailwheelflyer]

IMG_8821_3.jpg
As of August 2023, All aircraft leaving the kit factory will have skin stiffeners in the upper skin. These aid in controlling the airflow and some oil canning that had been observed. There is no structural requirement to have them but they make for a cleaner looking aircraft.