Walt Shipley
Active Member
Since posting my original "wing wobble" message a week or two ago, I now have a much better understanding of the problem.
Originally I thought the fore/aft play could be solved by increasing the thickness of the W-1207B doublers with shims. Ken Scott set me straight on that issue: Play is actually caused by the 1207B's being too short, a situation that arises from over trimming the inboard ends. And it doesn't take much - maybe .010" or so.
The solution, according to an information sheet Ken sent me, is to "Tape a dial caliper to the wing skin and adjust it so it just touches the side of the fuselage. (Use a spacer between the caliper and the wing skin, if necessary, to clear the rubber wingroot seal.)One person can rock the wingtip foward and aft while the other checks the indicator, and measures the total play."
After measuring, if the play is .010" or greater, the old doubler has to be drilled out and replaced with a longer one, which Van's stocks.
When I measured the play in my wings, I got .012" on the right wing and
.029" on the left one.
Since both wings had more than the mimimum accetpable play, I ordered two replacement doublers from Vans. These oversize doublers are
available in four over sizes, ascending in length from .010 over size to .045.
As I recall they cost $11.50/ea.
Ken said they have become aware of a few RV-12 with excessive play, but I'm wondering if there aren't more out there than a "few."
Walt Shipley
Originally I thought the fore/aft play could be solved by increasing the thickness of the W-1207B doublers with shims. Ken Scott set me straight on that issue: Play is actually caused by the 1207B's being too short, a situation that arises from over trimming the inboard ends. And it doesn't take much - maybe .010" or so.
The solution, according to an information sheet Ken sent me, is to "Tape a dial caliper to the wing skin and adjust it so it just touches the side of the fuselage. (Use a spacer between the caliper and the wing skin, if necessary, to clear the rubber wingroot seal.)One person can rock the wingtip foward and aft while the other checks the indicator, and measures the total play."
After measuring, if the play is .010" or greater, the old doubler has to be drilled out and replaced with a longer one, which Van's stocks.
When I measured the play in my wings, I got .012" on the right wing and
.029" on the left one.
Since both wings had more than the mimimum accetpable play, I ordered two replacement doublers from Vans. These oversize doublers are
available in four over sizes, ascending in length from .010 over size to .045.
As I recall they cost $11.50/ea.
Ken said they have become aware of a few RV-12 with excessive play, but I'm wondering if there aren't more out there than a "few."
Walt Shipley