I've encountered a puzzle with my 4-place A-Model flap hinges.
Background info: Kit was manufactured in 2006. The hinge plates (sheet metal parts that bolt up to the flap spar) were delivered cut, bent, and primed, but without any holes drilled in them.
The plans call for MS21152-2 rod end bearings to act as the "hinge" between the hinge plates on the flap and the tube in the mounting bracket that extends aft from the rear spar of the wing. I have some old/crummy/unusable MS21152-2 rod end bearings on hand, and a full set of custom "made to spec" rod end bearings purchased directly from Mark Goldberg at Avipro last year. I want to use the Avipro bearings for flight.
I've drilled the 1/4" hole for the rod end bearings in the first pair of mounting plates, in the location called for in the plans. The MS21152-2 rod end fits well, but the Avipro custom bearing binds up between the hinge plates.
To me it appears that the hinge plates (only the outer ones, not the center one with the actuator arm) are much larger than called for in the drawings. The oversized hinge plates, with the MS bearings, works fine. And, the custom bearings, with "in spec" hinge plates should work fine too. But the combination of oversize plates with the custom bearings seems to be problematic. Maybe someone's seen this before, or it's just a corner case that's bitten me!
think if I remove material from the plates to bring them into spec all will be good. I'd appreciated feedback before I start grinding though!
Here are some photos of the problem, and my plan of attack:
IMG_4709.jpg
IMG_4710.jpg
Here's the subtle difference in the bearings:
IMG_4713.jpg
Here's the hinge plate with the excess (I think) material:
IMG_4716.jpg
Comparison of sample "end" hinge plate with the middle plate which has the actuator arm.
IMG_4717.jpg
Rough outline of excess material I plan to remove:
IMG_4720.jpg
IMG_4721.jpg
Any advice would be welcome - thanks!
Background info: Kit was manufactured in 2006. The hinge plates (sheet metal parts that bolt up to the flap spar) were delivered cut, bent, and primed, but without any holes drilled in them.
The plans call for MS21152-2 rod end bearings to act as the "hinge" between the hinge plates on the flap and the tube in the mounting bracket that extends aft from the rear spar of the wing. I have some old/crummy/unusable MS21152-2 rod end bearings on hand, and a full set of custom "made to spec" rod end bearings purchased directly from Mark Goldberg at Avipro last year. I want to use the Avipro bearings for flight.
I've drilled the 1/4" hole for the rod end bearings in the first pair of mounting plates, in the location called for in the plans. The MS21152-2 rod end fits well, but the Avipro custom bearing binds up between the hinge plates.
To me it appears that the hinge plates (only the outer ones, not the center one with the actuator arm) are much larger than called for in the drawings. The oversized hinge plates, with the MS bearings, works fine. And, the custom bearings, with "in spec" hinge plates should work fine too. But the combination of oversize plates with the custom bearings seems to be problematic. Maybe someone's seen this before, or it's just a corner case that's bitten me!
think if I remove material from the plates to bring them into spec all will be good. I'd appreciated feedback before I start grinding though!
Here are some photos of the problem, and my plan of attack:
IMG_4709.jpg
IMG_4710.jpg
Here's the subtle difference in the bearings:
IMG_4713.jpg
Here's the hinge plate with the excess (I think) material:
IMG_4716.jpg
Comparison of sample "end" hinge plate with the middle plate which has the actuator arm.
IMG_4717.jpg
Rough outline of excess material I plan to remove:
IMG_4720.jpg
IMG_4721.jpg
Any advice would be welcome - thanks!
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