As previously mentioned in prior posts, the fit
of the RV-12’s parts thus far has been nothing less than superb … which
reflects the quality of Oregon
based Van’s Aircraft’s kit components.
That said, there are places in the instructions where you end up scratching
your head and say to yourself … “what”??. The flaperon instructions created one
of those moments. Case in point: The instructions tell the builder to build the
right flaperon as a mirror image of the left flaperon. OK, a mirror image is a
reflected duplication of an object which appears “identical” but is reversed.
Sounds simple enough right?
So what’s the confusion? Well, the plans have
the builder rivet the A-1208 bracket onto the A-1210L nose rib. So far so good,
then the assembly is riveted onto the inboard end of the left flaperon’s spar.
I almost got myself into trouble because I was going to rivet the second A-1208
bracket onto the A-1210L nose rib but the only thing preventing me from doing
so was my deviating from the plans with the assembly order … thought it best to
wait until after the left flaperon was completed before doing any work on
components for the right flaperon. That way if it was necessary to order
replacement parts due to a screw up, it would only be parts for one flaperon.
Instructions for creating the A-1210L nose rib/bracket
Because a mirror’s reflection would not roll the
components of the reflected image (or part mumbers) from the inside of a
structure to the outside of a structure, on the surface of things one would
think the second A-1210L nose rib/bracket assembly would also be placed at the
inboard end of the right flaperon spar but flipped around ... NOT SO!
Fortunately, a while back, time was taken to review how parts fit together and quickly
realized when the A-1207R actuator was placed on the flaperon’s right spar, the
actuator’s bolt hole dictates correct positioning the A-1210 nose rib/bracket assembly
... and the A-1210L assembly would not fit correctly at that location.
A-1207 L&R actuator brackets (these used to
be fabricated by the builder).
The right A-1210R nose rib was tested and it
appeared to fit correctly ... but that rib is inside the left flaperon about a
third of the way from the inboard edge. So
it can’t be a mirror image as suggested in the instructions. Knowing the parts appeared
to fit if the left nose ribs were reversed with right nose ribs, guessed that must be what Van’s wanted
... but that is not a mirror image as suggested in the instructions. So
thinking I must be more daft than usual and missing something, a call was
placed to Vans for clarification. Well, the positions of the right and left
nose ribs are flip-flopped as I guessed and the aft ribs can be left facing
outboard as on the left flaperon. However, I found it interesting Van’s builder support still
considered that to be a “mirror image”. Sorry Van’s … words mean things, technically
it is NOT! We agreed to disagree.
Bellow is a photo of Van’s left flaperon drawing
with blue arrows pointing to the ribs that need to be flip flopped to create
the “Oregon Mirror Image” followed by a photo of the correct placement of the
A-1208 bracket on the left and right A-1210 nose ribs.
Left flaperon drawing - blue arrows point
to nose ribs that require being flip-flopped when constructing the right
Correct placement of A-1208 brackets on the
A-1210 nose ribs ... the
A-1210L nose rib is on the left and the A-1210R nose
rib is on the right.
Honestly, all that would have been necessary to
head off any confusion for the builder would be to add another sentence in the
instructions saying rivet the remaining A-1208 bracket onto the A-1210R nose
rib and say the position of ALL the R & L nose ribs are flip-flopped when
assembling the right flaperon. Problem solved.