Horizontal Stabilizer Airfoil for QB

[Archer39J]

Researching I found people making horizontal stabilizers with an airfoil profile. As I understand my quickbuild kit will come with the tail already welded making this modification difficult compared to the examples I've seen. So I was thinking of a way to retrofit airfoil ribs to the HS and this is what I came up with. I modeled this up super quick so edge margins and profile are still TBD, I'm just curious what you guys think about the idea of splitting a rib in this fashion?

Info taken from this thread: https://bearhawkforums.com/forum/bea...-tail-surfaces

[Chris In Milwaukee]

If you're ordering a QB kit soon, it will be the "B" model, which has the airfoil shaped tail from the factory. No updates required.

For those who are buying or building a non-B model (original), Mark has a set of wooden airfoil-shaped blocks that you can epoxy to the existing ribs to get the airfoil shape.

That said, I don't think your idea is a bad one. Are those ribs steel or aluminum? Presuming steel, they'll likely have to be welded to the existing ribs, which shouldn't be a big deal. Aluminum rivets and steel ribs are something to watch out for, corrosion-wise, if that's what you were thinking for fastening. Same story if you're riveting aluminum ribs to the already-existing steel structure back there.

[Archer39J]

Ah, I was unaware the new kits come with an airfoil HS making this a non-issue. Aluminum ribs, and the rivets should be AL as well.

Thanks

[MitchG]

Rather than start a new thread........Can anyone point me to some pics of the actual new "B model" airfoil stabilizer ribs and their attachment to
the rest of the stabilizer structure? Only have the "A model" plans but "B's" are on the way.

[Chris In Milwaukee]

Rather than start a new thread........Can anyone point me to some pics of the actual new "B model" airfoil stabilizer ribs and their attachment to
the rest of the stabilizer structure? Only have the "A model" plans but "B's" are on the way.

Instead of rectangular ribs like in the A, they’re an airfoil-shaped rib, welded to the fore/aft tubes. This is the Patrol tail, but should be the same. Unless you’re retrofitting, which is a wooden piece epoxied to the bottom and top of the rectangular ribs.

[MitchG]

Thanks Chris, excactly what I was looking for and I can answer all my questions now!

[JCD23]

What angle of incidence should the Horizontal Stabilizer be set at on an "A" Model with the Airfoil rib attachments?

Hoping some one can point me in the right direction here.

[Mark Goldberg]

-3 degrees. With the airfoil shaped ribs it goes from -4 degrees to -3. The leading edge strut is usually too short when you make the change. Mark