VincentJ

Tonight's lesson/topic is about hard-points. If you've never hear of hard-points then read on...

One thing that bothers me when I see a nice plane that someone built, is when they don't use hard-points under their control horns. How can you tell their not there? Easy, just look for the crushed balsa under the control horns. Often times their so bad the horn sits at an angle because the balsa is crushed. If hard points were installed under the control horn, it would be nearly impossible to crush the end grain of the hardwood dowel under the horn. When installed properly, hard-points are undetectable under the horn, they should never sit proud of the surface.





Two short lengths of 3/8" hardwood dowel with 1/8" holes drilled in their centers. These will become the hard-points.




After locating and marking the exact position for the hard point on the aileron, a 3/8" hole is drilled. I like to place painters tape over the spot before drilling into soft balsa.




This is what the hole looks like with the tape removed. Time to glue the hard-points in place and let them dry.




Your hard-point should be a smaller diameter than the horn's base.




You probably already know the importance of making sure that the horn's pivot point must be directly over the hinge line for correct linkage geometry.