Discussion in 'Pitts Wings' started by luftwicker07, Nov 30, 2017.
Let's see how you guys have built your wing roots to facilitate mounting fairings.
For my Pitts:
With the wings assembled to the fuselage I made card stock patterns of triangle brackets which mounted (wood screws) to the face of the inboard rib and extended toward the fuselage. This is for the bottom of the wing. I used flat pieces of card stock held over them to get the brackets the right size to fair with the wing and fuselage.
After I installed them, again with card stock made flat patterns for sheet metal to cover the gap.
The top gap is covered with just a flat sheet wood screwed to the wing and after many cut and fit tries, fits against the fuselage side. I installed a little rubber channel on the edge where it touches the fuse.
Ref to Pitts bottom wing at the root next to the fuselage. Is there anyway to make a fairings without using screws into the wing root ribs?
I have seen it done on gap fairings where the wing attaches to the center section some distance from the fuselage by using those clamps usually used to go around a tube and screwed tight. What this builder did was to bend it straight and rivet it to the fairings. He left a hole in the rear to have access to tighten the fairings with a screw driver.
But on the Pitts at the root you can not do that due to to the curve of the airfoil.
I inserted these into a set of wings during the build to attach fairings. on the lowers they are in the wingwalk ply, on the uppers i glued in a ply strip flush to the inboard side of the butt rib.
I used a different approach.
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Link tip: While at the target post, click the post# to the right; this will give you the direct link to that post within a thread.
Beej, is there a way to link to a given post # within the thread, as opposed to linking to the individual post?
Kinda... after going to the specific post link, there is another link top right that opens up the post within the thread..
Ah yes, that's the one. Pity it's two-step (I usually find that viewing a post in isolation is less useful than being able to see it in the thread). At least I know now that you can get to the thread from the individual post.
Like you approach taff and Beej.
But on the Pitts S-1C with the up-sweep of the M-6 airfoil there is a problem with the
gap on top near the T.E. How do you close that gap without using screws into the wing root wing.
Also is there a big difference in just leaving the fairing off altogether vs using a fairing?
Bingelis suggested in one of his books that any 90 degree or greater joint should be faired to reduce drag, though he was talking about a fairing that smooths the joint between the two surfaces, rather than something that closes the gap as taff shows. Presumably a fairing like that (like a fillet on a joint) would require not only support in the wing, but also support in the fuselage.
Just run #6 self tapping screws into the wood and then take them back out. harden the "threads" with thin model airplane CA glue. put screws back in. will be good for many removal and installs. they will not come loose. when the day comes they get stripped, stick a tooth pick in the hole, add more super glue and thread the screw back in. lightest and simplest option and it works great!
Help me out Ian.
I am trying to understand. I think you mean a fairing that has a large curve set in the shape.
The wing is rigid and I am thinking that the wing root to fuselage side is also rigid.
The fuselage side panel is removable (in my case). Some Skybolts have fabric going up to the front cockpit.
If I understand you, making a faired or curved fairing (something from molded fiberglass for example) This rigid wing root fairing would be ideal if it were butted up to a continuous rigid fuselage side wall.
I am prepared to forgo the reduced drag for manufacturing and installation simplicity.
Yes, there will be a very small gap between my fairing (rubber edge trim installed) and the fuselage. This should avoid chafing from fairing to fuselage panel or fabric.
This is what it looks like now (well at the time the photo's were taken)
I need to paint them so they are on the shelf at the moment .
My Spezio has faired fiberglass wing root fairings. Attached only to blocks in fuselage that were glued to stringers, not attached to wing
Probably best if faired at 90 degree or more but much more important to seal the gap. My EAA bipe didn't have any and there was a noticeable increase in performance when I added them.
I simply screwed into the butt rib as Chris said on both the EAA and AD2. Didn't use any glue except to repair if they become stripped.
My AD2 fairings look exactly like taff's(on top).
Taff, I suspect I was thinking about it wrong: you're right, a rigid fairing between fuselage and wing wouldn't need to be attached to both surfaces, one should be enough. And I am most certainly not saying you're doing it wrong, I was just recalling something I'd read in one of the Bingelis books that I found noteworthy at the time: that joints of 90 degrees or more should ideally be faired in. I think it was in the context of drag reduction, and I'm pretty sure he was talking about monoplanes without a bunch of wires and struts hanging out in the breeze. I remember thinking as I read it that it seemed like a too-strong rule that wasn't widely followed, based on what I'd seen on real airplanes.
I apologize for writing in a way that might have caused you to feel any slight on the fairings you're putting together. That was definitely not my intention. First, I'm in no position to judge, and second, I'll be thrilled if my wing roots look as good as yours.
Looks great Taff. Is the upper fairing screwed into the wing walk?
Not into the wing walk. The top fairing is screwed to anchor nuts riveted to the wing walk.
In no way did I feel slighted. No fear. I was explaining that making a curved or faired fairing would be difficult to say the least. Even though it would look very nice.
I know some have made curved forms out of clay or whatever to get the shape and then layed down glass fiber to manufacture the fairings. I envy their drive.
I do agree with the theory of faired in protrusions but I am trading my need for a Lancair for one with lots of speed brakes.
I only attached the fairing to the fuselage, no screws into the wing, as other have said. This was my hanger partners S-1 and we made the fairings from my S-1-11 mold. The front fairing is not needed but cleans up the landing gear, it also dosn't attach to the wing.
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