A

avi8tor50

Well Known Member
Quick question. Mounting the VS. I understand there is an offset to the left.
How does one line up the front spar of the VS against the F-981 attachment plate? Do you center the spar on the plate? Or does the left edge of the spar go against the left edge of the plate or right edge to right plate?

Peter Katz
9A QB
 
offset

Mine is a -7A, but I think it's about the same. The offset called for is about a 1/4" at the leading edge of the VS (from memory). I used the center hole in the first bulkead forward of the VS for reference. However, as I recall, it you just slip in one standard washer under a bolt where the main spar of the VS is mounted to the bracket on the fuse, where Van's says to, then it comes out OK.
 
I asked Vans a similar question. Their reply was, "center the F-981 plate on the front spar web. This will give you the proper VS offset".
Fin
9A
 
Van's answer makes sense

If I remember right, the part in question has a built-in offset, so that will work.
 
Pics from RV-7 plans

I thought the -9 was the same as the -7 in this area. Maybe it isn't, as my plans are for the RV-7 ONLY.
But, have a look as it is quite specific in this area and may give you a clue.
Pete.
vsattachtq3.jpg
 
Center the spar on the plate. Some C-clamps will help here.

Also, before you drill anything, check the fit because sometimes it's better to have the plate aft of the spar, and sometimes it's better to have the spar aft of the plate. It depends on how those hinge holes are lining up for you on the back.
 
Changing offset to the other side for anti-clockwise engine?

A question that is in line with this thread:
As an alternative for a Diesel engine, I am considering installing a 160 HP Limbach Turbo engine in my RV9A. Unfortunately that engine turns anti-clockwise. That means I will have to make a new bracket with the offset the other way. That should not be to much of a problem, it will just be a mirror-image of the original, but what about the fuselage to empennage fairing, does that also have the offset build in? or do I have to make it fit myself? If that is the case, it makes no difference weather I will have to make it fit to the left or to the right.

Regards, PilotTonny

 
But how much offset.

Tonny,
I can't comment on any of our questions, but the amount of offset is also going to be determined by the RPM of your prop; as this will determine the tightness of the helix of the prop wash. And I don't know how that is determined, but it may be significant.
Pete.
 
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