Fitting vertical fin

[Sonex1243]

I have been struggling with fitting the vertical fin in place. It is extremely tight and have been flexing the vertical fin rear spar and tail post assembly a bit to let it slide into place. The problem is then trying to get the forward spar to clear the turtledeck skin in order to slide it in place. I have already slightly bent the turtledeck skin and slightly tweaked the tail post on the side that is riveted while trying to mesh the entire vertical in place to see how much trimming is needed on the skin.

What have others done and have you run into this? Is it as simple as trimming the turtledeck skins enough to clearance the forward spar?


Riveted side that flexes the tail post while trying to slide the vertical in place


Forward spar scraping and slightly bending the skin edge while trying to position in the slot


Non riveted / rudder hinge side that flexes outward while trying to slide the vertical in place

[gammaxy]

I think you'll be fine once you trim the turtledeck. It's a pretty common interference. I think the plans dimensions would work if you could teleport the tail into position, but otherwise you have to do some trimming.

This picture's not great, but you might notice I just blended the notch much wider until it fit. Can't tell there was ever a notch there.

[Rofomoto]

Had to widen the turtle deck cut out a 1/4” to each side. 1/2” total.

[Sonex1243]

I think you'll be fine once you trim the turtledeck. It's a pretty common interference. I think the plans dimensions would work if you could teleport the tail into position, but otherwise you have to do some trimming.

This picture's not great, but you might notice I just blended the notch much wider until it fit. Can't tell there was ever a notch there.

That's the visual cue I needed! Looks like you trimmed the entire turtledeck edge even with the front spar face. Was there enough meat for the fairing to attach to the turtledeck after trimming?

[sonex1374]

It looks like the very aft end of the fuselage upper longerons might be pinching the vertical stab spar as well. If that happens, you might need to file this down a bit. The very edge could conceivably dig into the vertical stab spar material and cause scratches or stress risers. The plans show this edge getting a slight shaping to it, but at the time it's not clear why. I've noticed this occurrence in several projects and they tend to need a bit more clearance at the time the tail goes into place.

Jeff

[pfhoeycfi]

I trimmed the turtledeck as well...

[Sonex1243]

It looks like the very aft end of the fuselage upper longerons might be pinching the vertical stab spar as well. If that happens, you might need to file this down a bit. The very edge could conceivably dig into the vertical stab spar material and cause scratches or stress risers. The plans show this edge getting a slight shaping to it, but at the time it's not clear why. I've noticed this occurrence in several projects and they tend to need a bit more clearance at the time the tail goes into place. Jeff

Thanks for pointing that out Jeff. I might be ok depending on getting the vertical in the right spot for drilling the forward attach bolts. If I need to file, it might be easier to just drill out the rivets and remove the tail post.

For now, I am struggling with the forward spar and have to use a small "C" clamp just to draw it in to the forward horizontal spar.