... By adjusting the
chord of the jig, you can measure to the trailing edge of the top skin, or the
trailing edge of the flap, or whatever point you want to check. See attached drawing.
Mike,
That's a very good jig, and useful for
similar applications as you noted. Having watched the postings about "factory
alignment" over the past few days, I thought it useful to comment on my
experience with my IV-P. I have one of the early "fast build" kits--by today's
standard it would be considered a slooooow build, but when compared to the
original IV/IV-P kits, it was pretty impressive.
In the 1998-1999 time frame, we had a
considerable discussion on wing incidence and twist in this forum, and I
carefully checked my wings for both. They were accurate and symmetrical to the
limit of my ability to measure them. I did find that I'd installed the left
wing with about 0.3 degrees more incidence, which I corrected by clamping it
in the proper position and redrilling the rear spar bolt to a larger
size. That was a LONG time ago, and without going into detail, I'll say that
the measurement technique I used was crude and time consuming.
Now that the airplane is painted and in
final assembly, I intend to level it and check both the wings and tail using
your technique. The thought of finding an error scares me a bit--difficult to
impossible to correct at this point--but the need to know before flying
it far outweighs the alternative.
My continuing observation is that these
are "home builts" and not certificated production line machines. I expected
Lancair to take reasonable precautions and care in their work, and have found
them to have done so consistently over many years--it's why I chose their
airplane kit to build in the first place. I also expect that they will
make a mistake from time to time, and I assumed the responsibility for
discovering if they (or I) had done so. I've checked everything I (and
others) could think of to check, and it's been both a learning
experience and a significant confidence builder.
Again, many thanks for the tip on wing
measurement technique!
Bob Pastusek