Flap Hinge Bracket Straightness

How straight is straight enough? The plans say to straighten these using a straight edge. Well, they are about 1/4" thick and banging them with a mallet did nothing...so how did you do it?

Second, how much should I care? I used feeler gauges to quantify my "out of straightness" condition...I am inclined to say this is good enough (as they came from factory).

LAMPSguy said:

How straight is straight enough? The plans say to straighten these using a straight edge. Well, they are about 1/4" thick and banging them with a mallet did nothing...so how did you do it?

Second, how much should I care? I used feeler gauges to quantify my "out of straightness" condition...I am inclined to say this is good enough (as they came from factory).

Click to expand...

Isn't it that same factory that instructed you to straighten them?

Checking at the mid point with a feeler gauge isn't really going to tell you the entire story.

Hold the fwd end flush against a flat surface and measure how much the aft (flap hinge point) end lifts off the table. You should strive for trying to get it close to net with the same surface.
Don't worry about the straightness in the vertical plane... concentrate on them along their length or your flaps will be displaced to one side from where the are intended to be (this can cause clearance problems with the clearance to the aileron and fuselage).

Use a vise

Stuff like this is usually fairly easy to straighten with a vise. Place the part lengthwise in the vise. Two vertical sticks on the concave side strategically placed. One vertical stick on the convex side centered between the others on the opposite side. Go slow and bump the part at various locations using progressively more umph until the part yields a bit.

Oh, and don't forget to hold your mouth right.

Understand

I guess you are saying to squeeze it in the vise with a dowel on the high point and two opposite it on the concave side and just keep "tweaking" it until I get it as flat as I can?

This is the hard part for us new builders...some things I am being told I worry too much (deburring, holes not aligning PERFECTLY, etc), then other times I am told I don't worry enough. Bottom line...I still enjoy the entire process!

LAMPSguy said:

I guess you are saying to squeeze it in the vise with a dowel on the high point and two opposite it on the concave side and just keep "tweaking" it until I get it as flat as I can?

Click to expand...

You got it. The trick is to space the two dowels on the concave side the correct distance apart. If you place them too far apart the material never yields and just springs back. If you space them too close together, the material yields too much and you end up with a little kink in the material. Go slow and start with the two dowels spread about 3" apart and then move them closer as needed.