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ChrisL

Active Member
I have been working on the empennage attach for my RV-7 and after having all the bolts line up with perfect edge distance, I have decided to take another set of measurements now that everything has been deburred / primed and bolted down. Unfortunately it looks like a few things shifted around a bit -

Horizontal Stabilizer - 1/8" forward on the right side measuring over 164" from the corners of the firewall

Vertical Stabilizer - 3/32" to the left measuring over the 62" from the tip of the VS to the tips of the HS.

Rudder hinge line - Top hinge bracket is forward about 1/8" when lined with the lower two brackets. I compensated for thisby extending the top rod bearing on the rudder by 1.5 turns.

Should I be concerned about the flying properties of the plane, or am I just trying to find something to worry about since all the edge distances came out fine???

Thanks,
Chris
 
ChrisL said:
I have been working on the empennage attach for my RV-7 and after having all the bolts line up with perfect edge distance, I have decided to take another set of measurements now that everything has been deburred / primed and bolted down. Unfortunately it looks like a few things shifted around a bit -

Horizontal Stabilizer - 1/8" forward on the right side measuring over 164" from the corners of the firewall

Vertical Stabilizer - 3/32" to the left measuring over the 62" from the tip of the VS to the tips of the HS.

Rudder hinge line - Top hinge bracket is forward about 1/8" when lined with the lower two brackets. I compensated for thisby extending the top rod bearing on the rudder by 1.5 turns.

Should I be concerned about the flying properties of the plane, or am I just trying to find something to worry about since all the edge distances came out fine???

Thanks,
Chris
Click to expand...

It never hurts to try for perfection, but it sounds like you have a very straight airplane--it'll fly fine.

Build on. :)
 
Perfect?

"Perfect is the enemy of good because good will never be 'good enough'." ;)

What is the alternative? Re-build? As stated by Bob: Yours may be the best out there (probably not if you are a first time builder) but I can assure you it is not the worst by a long shot because of the attention to detail that you exhibit in expressing your concern!
 
Thanks everyone - I love this site.

I realize these are small deviations, but I keep thinking about the first flight and want to make sure after all this effort, that she flys straight and true. It's just great to get input from all those who have "been there and done that".

Thanks,
Chris
 
I found that

I needed to add washers to BOTH (upper and lower) left side VS spar to fus attach bolts. You know, the washer that makes up for VS offset to the left. My plans only called for a washer for the upper left side. This helped with my hinge alignment.

About the other measurements, mine was different by 1/16" to 3/32" every time I measured it. I think they continue to move around for a few weeks:rolleyes:
 
The rear spar

ChrisL said:
Thanks everyone - I love this site.

I realize these are small deviations, but I keep thinking about the first flight and want to make sure after all this effort, that she flys straight and true. It's just great to get input from all those who have "been there and done that".

Thanks,
Chris
Click to expand...

....bolt holes are the critical ones. Be sure that when you get to that point, you get very, very close to having both wings to have the same incidence.

Regards,
 
There is one problem...

ChrisL said:
I have been working on the empennage attach for my RV-7 and after having all the bolts line up with perfect edge distance, I have decided to take another set of measurements now that everything has been deburred / primed and bolted down. Unfortunately it looks like a few things shifted around a bit -

Horizontal Stabilizer - 1/8" forward on the right side measuring over 164" from the corners of the firewall

Vertical Stabilizer - 3/32" to the left measuring over the 62" from the tip of the VS to the tips of the HS.

Rudder hinge line - Top hinge bracket is forward about 1/8" when lined with the lower two brackets. I compensated for thisby extending the top rod bearing on the rudder by 1.5 turns.

Should I be concerned about the flying properties of the plane, or am I just trying to find something to worry about since all the edge distances came out fine???

Thanks,
Chris
Click to expand...

As already mentioned, all of your position measurements don't show a problem...except the last one.
A misalignment of the rudder hinges is a problem. This is one of the causes of skin cracks on rudders. If the hinge points aren't aligned and you simply compensate with the rod ends, you will be flexing your rudder a lot every time it swings from neutral. An 1/8 inch of misalignmenty is a lot. I bet that your rudder just about returns to neutral by it self when displaced to one side or the other.
 
Any thoughts on how to correct? It was spot on when i clamped and drilled, but now that I have the washer in between the VS spar and the elevator stop angle, it is off...

Chris
 
ChrisL said:
Any thoughts on how to correct? It was spot on when i clamped and drilled, but now that I have the washer in between the VS spar and the elevator stop angle, it is off...

Chris
Click to expand...

The only thing you can really do at this point is remove the bent splice plate and match drill a new one.
Make sure you have temporary bolts installed in all of the holes in the vertical stab spar with properly torqued nuts and the correct spacer washers on the left side allowing for the stab off set. Use a long straight edge (good quality carpenters level works well) to verify that all of the hinge brackets are aligned with each other before drilling the new splice plate (a piece of thread stretched tight through the bolt holes in the brackets can be used to verify alignment if you don't have a long straight edge).
 
Remember, the reason for having a pilot on board is really to correct any out of trim conditions which may be caused in the building process!! You will do fine as I am sure many others are off more than you are.

Dick DeCramer
RV6 N500DD Flying
RV8 in the works
Northfield, MN
 
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