What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Tail Offset

S

SuperDave

Active Member
My buddy and I have been looking at an RV-8 that is for sale but is currently stored with it's wings and tail removed. I noticed that where it appears the (lower rudder bracket?) bolts to the rear of the fuselage the holes are offset slightly to the left (looking from the rear). I know it is fairly common to offset the vertical stabilizer to offset the p-factor but I couldn't make sense of why it appears that the rudder and/or vertical stabilizer are offset to the LEFT. Would this be something that the builder would drill per the plans? It seems that if it produces a vert. stab. that is angled to the right that would create a tendency to turn left.
We are satisfied with the build quality but this has us puzzled.
Any input would be greatly appreciated.
 
Leading edge of the vertical stabilizer is offset to the left, producing a right turn tendency, thereby counteracting "P"-factor.
 
Mel,
Thanks for the response. That was what I was thinking too but it appears that the REAR of the vertical stabilizer and/or rudder is offset to the left on this -8. Does Van's specify in the plans that the front and/or rear attach points have offsets? I'm assuming that it would be similar on all models.
Would that be a factory made piece that was possibly installed backwards?
I should have taken a picture:(
 
no offset

Unless something has changed there should be no offset on the tail. The engine mount is offset on the -8.
 
Hi Dave. I am at work so don't have access to the plans but as far as I recall all the measurements for the tailplane are equal ie no offset.
 
Thanks guys!
It sounds like it is unanimous that the mount holes at the rear should all be centered....and these aren't. Since this plane is disassembled we were going to have to violate our "fly it before you buy it" rule which was made to avoid these issues.
Thanks again for your input.
 
SuperDave said:
Thanks guys!
It sounds like it is unanimous that the mount holes at the rear should all be centered....and these aren't. Since this plane is disassembled we were going to have to violate our "fly it before you buy it" rule which was made to avoid these issues.
Thanks again for your input.
Click to expand...

Nobody says you can't offset the tail, although it appears this one is opposite of the normal function. The RV6's (at least the short tails) are not offset either, but most require a trim tab or wedge instead. If they don't, then something else could be crooked... :eek:
 
Well maybe the builder was planning on using a motor that turns the "other" way. :)

Bird
 
bird said:
Well maybe the builder was planning on using a motor that turns the "other" way. :)

Bird
Click to expand...

I'll be sure to ask the builder if he was originally going to hang an M14 radial on the front. I think they rotate the opposite way. Probably gave up due to CG issues. Too many concrete blocks in the tail?
 
Pictures would help explain what is going on.

The 8 vertical stabilizer may have been slightly off center at the upper deck to vertical spar mounting angle to make up for some fuslelage twist. Twist in the fuselage is very common.

Some builders square things to the fuselage and some square things to level. Both can be OK, but squaring to level keeps all control surfaces level or squared to one another.

If the rest of the plane looks well done this may not be problem at all, but a sign that things were built well and square.

George
 
george meketa said:
Pictures would help explain what is going on.

The 8 vertical stabilizer may have been slightly off center at the upper deck to vertical spar mounting angle to make up for some fuslelage twist. Twist in the fuselage is very common.

Some builders square things to the fuselage and some square things to level. Both can be OK, but squaring to level keeps all control surfaces level or squared to one another.

If the rest of the plane looks well done this may not be problem at all, but a sign that things were built well and square.

George
Click to expand...

Thanks for the input, George. We're going to investigate further if at all possible and we'll definitely be taking some close up pictures of that area. The holes that I am talking about were offset just an 1/8 or 3/16. As I recall, there were multiple holes on the centerline of that rearmost piece and the 2 that were offset looked to be for an an-4 or an-5. The builder says it flies straight without even a rudder tab, but.....
 
You must log in or register to reply here.
Back
Top