Friday, June 15, 2012

Vans Aircraft RV-12 Build, Section 23 Side Skins (part 2)

Reference: page 23-02; 5.5 hours

Step 4: Clamp the F-1255_L Longeron in a padded vise at the start of curve line and pre-load the free end. using a rubber mallet, firmly strike the longeron adjacent to the vise to produce a bend. Repeat this process at one inch intervals to produce a curve that matches the template (F-1234-L Canopy Deck) within a sixteenth of an inch. See figure 1 on page 23-02 of the RV-12 plans.

Builder's note: I used the F-1234-R upside down as it cleared my vise and made the job easier.

Check the curve often to prevent over bending. The longron can be place in a six-inch vise without removing any of the bend, so it is easy to add more curve later. Remove curve by clamping the mid fuse langeron at the required point and pulling back slightly.

Check that the mid fuse longeron does not bend out of plane vertically as it is being bent in the horizontal direction. If this occurs, rotate the mid fuse longeron 90 degrees, clamp it in a vise, bend it back straight with your hands, then recheck the curve with the template.

The two pictures above are of the straightening process when the longeron is turned 90 degrees.

Clamp the longeron at the start of bend line at the aft portion of the longeron as shown in figure 1. Using the method described above bend a single bend in the longeron as shown in figure 1. As before check that the angle has not bent out of plane and adjust as before.

Step 6: Using a scrap of .025 thick aluminum to simulate the F-1270 Fuselage side skin, postion the F-1234 Canopy Deck to the F-1255- Longeron as shown in figure 2 of the RV-12 plans. (the canopy deck will overhang the longron by .025). Flush the aft edge of the canopy deck with the aft end of the template mark, then clamp the parts together. Match-drill #30 the longeron using the canopy deck as a drill guide. Take care when drilling to ensure that the drill is perpendicular to the canopy deck. Repeat this step to match drill both Longerons.

Builder's note: Use new or newly sharpen drill bits so they don't wonder. Also coleco as each hole as drilled.

Complete both longerons in the above mentioned process. This completes page 23-02. That wasn't so bad was it? Next time I will move on to the Roll bar attach plates of the Van's RV-12 Aircraft.