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Wing Incidence Measurement Needed Please RV-6A

W

WenEng

Well Known Member
Patron
Apparently the older directions for wing construction on the -6A referenced a ''figure 7-11'' which I guess gave the x and y measurements in order to drill a hole in the main spar web and the rear spar web to run a plumb line through in order to maintain the correct wing incidence when drilling the ribs for skin attachment. My kit did not have any such reference in the manual and I cannot find it. Those pages I believe were updated by Vans years back and the measurements are not in the current section 7. Can anyone either forward me the instruction page 7-11 that shows the x, and y coordinate measurements for drilling the plumb line holes in each spar, or is there some newer way to be sure of the correct alignment before I drill.

Thanks.
 
I don't have my manual here but...

The procedure given in my manual said to level the airplane with fwd & aft and side to side levels on the canopy deck. Then place a block of a specific size at a certain place on the rear spar and a straight edge between the upper camber of the wing and the top of this block should be level. My right wing was good but the left wing required adjustment. This is an important rigging step as you are obviously aware. If an answer doesn't show up I'll go to the hangar and dig out my manual - it is a 1996 small tail RV-6A kit.

Bob Axsom
 
Thanks Bob. However.....

I was referring to when you have a wing spar(s) mounted on a jig before you start drilling to construct the wing. There is some measurement, I think, that says.. measure x inches in from the wing root end and y inches in from the main and rear spar flange.... drill a small hole at that location on both the main and rear spar and drop a plumb line through.... be sure the two spars are plumb to each other before you construct the wing or else the chord will not be correct....

I dont' know where to drill the small plumb bob hole in the main and rear wing spar without some measurement of x and y....
 
alignment holes

The following from Frank Justice's supplementary instructions. If you aren't using these, you should, as they are very helpful. You can find them on the RV List website:

Main Spar

Jig Alignment Holes
Drill 1/16" holes through the main spar web as follows:
a. 7" from the tip end of the tab that was left for jigging and 4 29/32" from the top outside edge of the flange.
b. 99" from the tip end of the jigging tab and 4 29/32" from the top outside edge of the flange. (This number is for an RV-6. On an RV-4 or -3 just make sure the hole is where it is away from any ribs.)

Cleco the doubler to the spar and drill through these holes into it.
See SK-29 in the construction manual.

Rear Spar

Drill the two jig alignment holes 1/8" diameter, 2.335" (2 11/32) from the outside top edge of the spar (the edge where the flange is overbent) at 7'' and 99" from the end of the tab left at the tip end for jigging. To verify these positions, lay the rear spar against the main spar and see that they match lengthwise when the tip ends of the spars are aligned..

(Note that I have not compared the above with the RV-6A manual, which I don't have with me.)

Bill Brooks
Ottawa, Canada
RV-6A finish kit
 
Thanks Gil and Bill....

That explains what I needed. Now I just have to figure out why my manual doesn't have the sketches in it. Back to drilling..:D
 
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