Flap and Aileron Sleeve Bushings on Highlander

[mhcrowder]

According to the builder's manual, you're supposed to ream the holes to 5/16" inch and the bushings should go in easily, but not too tight or loose. After going to final assembly we've found that the bushings are too tight in the holes. What caught our attention was on the fact the flaps were not always returning to their "up" position. Loosening the bolts frees everything up and things start behaving as normal. After a lot of head scratching we determined the bushings were just too tight.

Has anyone else noticed this issue? Me and my build partner have just ordered oversized HSS reamers (0.3130, 0.3135, and 0.3140) to see if we can get smooth movement when everything is torqued down.

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Michael

[danerazz]

Mine pressed in, but not too tight (used fingers, snug fit) after reaming to specified dimension. When you assemble, you should make sure the bushing stands proud of the sides of the bracket it is in. When you tighten the bolt the aluminum brackets on the wing trailing edge should pinch the bushing but not touch the bracket on the control surface. The bushing should then remain stationary and the steel bracket rotate around the outer surface.

If your hinges are not perfectly aligned with each other it will cause binding, or if the holes are at an angle. They will otherwise quickly loosen up with some motion.

[mhcrowder]

Thanks Dane. Ours are VERY tight (i.e. too tight). We have to use a ViceGrip clamps to press them in. New oversized reamers showed up late last night so we're going to try and upsize the holes a little at a time. We also purchased new Sleeve bushings from McMaster Carr just in case.

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Michael

[mhcrowder]

After using the oversized reamers, the flaps now move without much effort. We also removed paint in the area to make sure it wasn't binding on it. All seems to be good now. Hope to have the DAR inspection sometime mid-July.

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Michael