[aarvig]

The rear wing spar on my RV-9A has doublers that mate with the web and then curl up to mate with the flange. When the skin is riveted on, the aft spar is wedged between the skin and the doubler (in two places). Where the doubler is located on the spar Van's recommends that you countersink the spar and dimple the skin then rivet the countersunk spar between the skin and doubler. I made the mistake of dimpling the spar and the doubler, as a result the doubler doesn't sit flush to the spar flange. Can I use a flat squeezer set and "flatten" the dimple out on the spar and then countersink the flattened dimple, then install a new doubler plate? I guess my question is...is it safe to flatten a dimple and then countersink it?

 

[rockwoodrv9]

pics

Aaron,
Do you have pictures or at least part numbers. I may have done the same thing! I will take a couple pics tomorrow and we can compare.

 

[aarvig]

The spar is W907A, the doublers are W907E, W907D and then the top skin.

 

[molson309]

If I understand correctly what you did, it's probably easier at this point to lightly countersink the dimple in the spar until the two dimples nest together. No need to flatten the dimple out to countersink it! In fact the result will most likely be stronger than simple countersinking and certainly stronger than flattening out the dimple first.

 

[aarvig]

If I understand correctly what you did, it's probably easier at this point to lightly countersink the dimple in the spar until the two dimples nest together. No need to flatten the dimple out to countersink it! In fact the result will most likely be stronger than simple countersinking and certainly stronger than flattening out the dimple first.

I tried this. Because of the "over 90 degree" bend in the spar flange and doubler flange it is nearly impossible for me to get the two pieces to nest together flush.