WXB-T07 Stabilator Install on Aft Fuselage

[Zack]

I'm test fitting my stabilator assembly to the fuselage (WXB-T07) and I'm running into interference with my Stabilator Forward Spar Plate and my turtledeck skin. Has anyone else experience this with the new Forward Stabilator Spar WIX-T11-07 "hockey stick" bend?

For background, I have a 2011 Waiex that I've upgraded to the B-model. I started by completing the tail before moving on to the wings and then the fuselage. When I had the aft fuselage completed, I test fit the stabilators. They fit in the channel and aligned with the WIX-T09-04 Lower Attach Angle, but not to my satisfaction. I believe this is due to inaccurate bend location and bend angle. There were variances in all three dimensions that I could take up with a C-clamp, but I did not want take them up with the AN3 bolts and over torque them. I've chosen to order another tail kit and remake the parts.

When my new tail kit arrived, I found a metal shop locally that would bend the Forward Stabilator Spar WIX-T11-07 with a 1/2" radius in the new location and angle (20 degrees). I've checked their work and it's spot on (they do this professionally after all). I completed the Right Hand Stabilator Substructure (no skin yet) and test fit it to the fuselage. When I lead with the Rear Stabilator Spar in the Y-fitting, the Forward Stabilator Spar interferes with the turtle deck skin. When I lead with the Forward Stabilator Spar, the Rear Stabilator Spar does not have the space to clear the Y-fitting. This did not happen with the old bend location. Since I have not completed final assembly of the Left hand Stabilator Substructure, I cleco'd it together in place (between the Y-fitting and the WIX-T09-04 Lower Attach Angle). It appears to fit fine.

Has anyone else had experience fitting the stabilators with the new bends? Is there some way to angle the stabliator so that it can be twisted into location? The only solution I can see is to loosen the Y-fitting from the aft fuselage, but I really don't want to go into the tail cone again if I don't need to. This would be the fourth time I've had to loosen / remove all of those AN3 bolts and then install / torque them (the first three times related to the install of the doubler).

[Bryan Cotton]

I am pretty sure I notched the turtledeck skin to clear. IIRC there is prior discussion on this, besides the answers you get I'd do a quick search.

[Rynoth]

You're definitely not alone in having the stabilator "hockey stick" spars positioned a bit forward of where it seems they should go in the plans.

viewtopic.php?f=42&t=1198

The turtledeck definitely needs to be notched for the spars, I believe the notch is called out in the side panel assembly pages. As long as you're aft of the last turtledeck former you should be OK (the stabilator skins will cover up a deep notch.) My spars were close enough to the aft turtledeck former that I had to drill holes in the former to insert the bolts from the front as there wasn't room for nuts on the forward side.

As referenced in the above link, a few of us used various methods to line up the top and bottom attach angles for the forward spar. I used a 1/8" x 1" plate in between the hockey sticks and the upper attach angle which worked great, and pretty clearly indicated to me that the as-built dimensions are a solid 1/8" off (spar is more forward) in this regard. Here's a link to pic where, if you look closely, you can see my spacer between the attach angle and the spar: http://www.rynoth.com/wordpress/wp-cont ... x-2815.jpg

There is still something definitely funky about the dimensions of the Waiex tail-to-fuselage fitment between the plans and how it actually comes out as built. I know a lot of us had issues with the positioning of the clip that holds the inboard stabilator rib to the forward spar, which would directly impact the final dimensions between the front/rear spars.

viewtopic.php?f=15&t=4363&hilit=waiex+clip

And, if I recall, they changed the hockey stick bend angle/location at some point which might also be the culprit.

[Bryan Cotton]

I recognize that post! Also check out page 23 and on a bit for my Y tail installation.
viewtopic.php?f=39&t=578&start=220

[Zack]

Thanks for the feedback. I matched the stabilator forward spar with the lower and upper attach angles before I built my second set of stabilator substructures. I wanted the benefits of the drill press (90 degree holes, simple clamping). I also final drilled the WIX-T09-04 lower attach angle and forward doubler bars to the longeron for the same reasons. Bryan, I liked your solution of building a larger WIX-T09-04 lower attach angle so you could drill the longeron farther forward and still keep a safe edge distance. Unfortunately, I don't have that option anymore because my longeron is drilled. I'll try the spacer like Ryan used and report back.

This problem is compounded by the new stabilator forward spar (hockey stick) bend location, IMO. The old bend location allowed me to place the Y-fitting in the rear stabilator spar channel and rotate the forward spar into position. The new bend location provides more space for the WIX-T11-6R clip, but I cannot rotate the forward spar into position without interference from the turtledeck. The clearance slots per the plans are too small. I'll have to clearance the turtledeck further or find space in the other side by loosening the bolts that attach the Y-fitting, allowing me to pull it back 1/8" to rotate the forward stabilator spar into position. I'm loathe to go into tail cone again though, I've been in three different times fussing with rear doubler!

In hindsight, my original stabilators are likely serviceable with a spacer and I didn't need to order a second tail kit. Dang! Although I am pleased with how the second pair of stabilators are turning out. I now have the benefit hundreds (thousands?) of hours of experience :)

Bryan, I'm impressed that you disassembled the stabilator assembly to replace the stabilator forward spar! I chose to rebuild the parts, which with a matched hole tail kit took no time at all.

[Bryan Cotton]

We make it nice because we make it twice.

[Zack]

Quick update. I relieved my turtledeck another 1/4" and the stabilator assembly rotated into place. The thought of loosening the tail cone AN3 bolts to make space was not appealing, especially so when I realized I'd have to test fit the stabilators multiple times to trim the skins to match the fuselage. It does look like the stabilator will cover the larger hole in the turtledeck, but I'll know for sure when I skin the stabilator and test fit again.

The forward stabilator spar is indeed 1/8" farther forward than the plans indicate. I created a 1/8" spacer from some extra 1 1/2" x 1 1/2" angle and it lines up perfectly. I still have to figure out how to get it bolted, but I have some ideas.