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.

Vans Aircraft RV-12 Build, Section 23 Side Skins

Reference: page 23-02; 2.5 hours

This entry starts the building of the fuselage side skins on Van's Aircraft RV-12 airplane. Bending and forming the Longerons can be challenging. It's not hard but it is a little unnerving to be beating on a piece of your new airplane! Take it slow and work your way through it. If still worried try picking up a piece of 1/2" aluminum angle from Home Depot and practice bending it. I'm still playing caught up with these postings, but it's all good!

Step 1: Cut the F-1255-L and -R Longerons from AA6-125X3/4X3/4 per dimensions in Figure 1 on page 23-02 of the RV-12 plans.

Step 2: Mark the end of the twist start and end of the curve, aft end of template and start of bend ines on the Longerons.



The picture above is taken at an angle so the parts look like they are marked in the wrong places.

Step 3: Open the angle of the longeron as shown in Figure 4 from the start of the longeron to the end of twist & open line as shown in Figure 1. Clamp the longeron in a padded vise at the end of twist & open line as shown in figure 1. Use a crescent wrench as shown in Figure 3 to twist the longeron inboard as shown and per the dimensions in figure 1. When finished the top faces of the longeron both fore and aft of the end of twist & open should lay flat against a table.

Durning this operation I found I needed a bigger hammer! The larger one you see pictured here is a 56 oz. soft face hammer from Home Depot. Yes it worked well.



Below are the before and after pictures of opening up the front ed of the longeron.





I found using a electronic level very helpful.



Well, that gets this section of the RV-12 airplane started. In addition to the above steps I started deburring some of the parts used for the side skins. Just remember walk softly and carry a big hammer!