Roee
What defects did you find in the QB?
John
Some of the top defects I remember off the top of my head, without pouring through my log:
- the F-719B-L angle clip was positioned too far forward causing an interference with the firewall. Instead of correcting the problem before installing the firewall, the QB assemblers evidently forced the structure together, noticeably deforming the firewall.
- the apex of the conical bends (both sides) in the fuselage skin in the area near the flaps had cracks. The relief holes were drilled but not deburred, and the bends were imprecise, putting the structure under significant preload. That's asking for a crack, and sure enough. I had to enlarge the holes carefully to remove the cracks and relieve the stress concentration.
- the F-786A upper stringers were installed about 1/2" forward of their correct position relative to the bulkheads. This slightly weakens the structure at the aft end, and also prevented one of the bulkheads from being in its correct position. Correcting this required some delicate surgery on the stringers while being very careful not to damage the adjacent bulkhead.
- the F-728A bellcrank channel had its forward flange insufficiently bent, so it was causing the web to sit at an angle and to interfere with F-787. These two parts which are not rigidly connected to each other would have rubbed against each other with vibration. That's a bad thing. Again, these were already riveted into the fuselage, so I had to do careful surgery in-place to remove the interference.
- the rivet holes that connect the engine mount supports to the main longerons and forward side skins were drilled grossly misaligned. I don't even know how the QB assemblers managed that screw up, unless they drilled the parts individually and not in assembly. Bad... Will likely have to enlarge some of these holes and install structural screws instead of rivets.
- two serious scratches on one of the wing spars that needed repair.
- various other defects along the same lines. Also just general poor fit (parts forced into assembly under stress) and poor deburring, which I felt needed to be corrected in some critical areas.
- and then of course there was the free gift under the baggage floor.
To be clear, I'm not trying to "bash" the QB kits. Despite these defects and other issues, I have no regrets about going QB. The point I was trying to get across is this: There will always be defects, even with the best of vendors. Perfect quality control is impossible to achieve (which is NOT to say they shouldn't strive to do better than they have in the past). In any case, there's always a chance that there will be hidden defects in your QB kit, and they won't necessarily be the same defects that were found in mine or anyone else's. That's why, if you care, you -- the recipient of the QB kit -- really have to just bite the bullet and inspect it head to toe with a fine toothed comb. It's your airplane, and it'll be your a** in the seat ;-)
-Roee
