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Bottom rudder fairing trimming

SonexGuy

Active Member
I've trimmed the bottom fiberglass rudder fairing to fit. The instructions say for a -7, to wait to install it in case any trimming has to be done for the tailwheel spring. Looking at pictures of other -7's, I can't see what might have to be trimmed.

I'm just wondering if I can at least drill the holes for the rivets, or if the whole fairing might need to be adjusted later, so I should wait on the holes.

Thanks,
 
Having just done this on my 7 last week, I would wait till you can test-fit the whole rudder on the plane so you can avoid a messy rework job later.

At the forward end, you want to have "adequate" clearance between the fairing and the front of the tail spring. 1/8" or more is probably fine, this dimension won't change much.

At the aft end, I wanted to make sure to have at least 2" between the bottom of the fairing and the top of the tailwheel assembly, to avoid having it put a hole in the fiberglass when it flexes.

Both of these dimensions are more or less impossible to gauge until you actually have the thing attached to the VS with the VS on the fuselage.
 
How did you determine "trim to fit"? The fairing is designed for the A model and has a lot of extra material on it that has to be removed for the tail dragger to clear the spring. Post a pic of what it looks like.
 
I agree with Mat.
It will need further trimming to clear the tail wheel stinger & on some airframes the lower front shape may need reshaping to clear the fuselage. Leave it for now & finalize it when you can trial fit on the fuselage.
 
The RV-14 instructions have more details on what needs to be trimmed off of the rudder fairing for the tail wheel on page 12-04. There is a template for the cut on page 12-15. It may not be exactly correct for the RV-7, but it does show how to cut the relief for the tail wheel and how to make a fiberglass patch for the fairing.
 
This picture is the best I have showing the "final" trimming for the bottom fairing. Notice mine is about 1" shorter than yours on the front side. There's a little more info on the tail fiberglass in this post:
https://www.rv7build.com/fiberglass-months-and-months-of-fiberglass/

The initial trim lines work fine for the A model, but you'll need extra trimming before it clears the tailwheel mount. As you take more and more off the front, the slot you made for the rudder horns will have to be widened as well because the angle is going to change. You're likely going to end up with a slot that is slightly too wide like I did. Its possible to fix that later if you're inclined to do so, but I don't think its that big of a deal if you choose not to.
 

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This picture is the best I have showing the "final" trimming for the bottom fairing. Notice mine is about 1" shorter than yours on the front side. There's a little more info on the tail fiberglass in this post:
https://www.rv7build.com/fiberglass-months-and-months-of-fiberglass/

The initial trim lines work fine for the A model, but you'll need extra trimming before it clears the tailwheel mount. As you take more and more off the front, the slot you made for the rudder horns will have to be widened as well because the angle is going to change. You're likely going to end up with a slot that is slightly too wide like I did. Its possible to fix that later if you're inclined to do so, but I don't think its that big of a deal if you choose not to.

Thanks, everyone. Now I understand, so I'll wait.
 
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