fitting analysis
fitting analysis
(OP)
I have to do a fitting analysis. In particular I'm interested in the joint analysis. The fitting has a clevis, bushings and it is connected to the lug of a second fitting with a pin.
Does anyone know in which JAR/FAR I read about the misalignment?
thanks
Does anyone know in which JAR/FAR I read about the misalignment?
thanks





RE: fitting analysis
RE: fitting analysis
Determine the max clearance between the pin and the hole, misalign the pin by that much and work the geometry. For inline loads, I've seen a Fitting Factor of 1.15 generally applied.
RE: fitting analysis
RE: fitting analysis
if the AC ... not surprising.
if your company doc's , then ask your supervisor what he thinks you should do.
how critical is this ? ... is the joint flight critical ? is the margin (without misalignment) small ? both reasons to investigate misalignment. is the margin large ? is the joint secondary structure ? both reasons not to fuss over it.
RE: fitting analysis
RE: fitting analysis
I can't use Boeing doc. I need a generic reference.
What does DER mean?
The use of the misalignment depend on the type of bearing?
RE: fitting analysis
I searched in the JAR 25, in the AC 43.13-2B.
I didn't find any info about misalignment.
RE: fitting analysis
for generic reference try Michael Niu, else use something like 10%. this is not used to define the bearing, but rather to account for "realities", like your load not being axial. The aileron hinge will almost certainly be installed with spherical bearings, the real world being that the two sides of the hinge don't exactly align and the spherical bearing releases the joint, so there is no internal moment/fixity, but the load can still be applied off axis ... clear as mud ?
RE: fitting analysis
Your finagle factor of 1.15 is right out of 23.625 and probably Part 25 and 27 as well.
The problem is the definition of "fitting"?? I understand a seat belt fitting that goes between the nylon webbing and the seat. But what if the manufacturer identifies a widget as a "bracket" and the FAA says to apply the 1.15 factor.
I disagree but sometimes it's easier to fold-em than fight!!
JQC DER/DAR