Tuesday, June 26, 2012

Vertical Stabilizer Assembly

Van’s plans call for blind (pop) rivets on the rear spar but since I have a pneumatic squeezer, solid rivets are being installed. Because I’m building the RV-12 as EAB (Experimental Amateur Built - discussed a few posts earlier) the plan is to use solid rivets wherever the squeezer fits … stronger, lighter and looks far nicer.
                                   Squeezing solid rivets to attach the left and right spar caps to the main spar.

Building the vertical stabilizer skeleton provided the opportunity to use more solid rivets. The rivets called for attaching the vertical stabilizer ribs to the spars are the LP-4 blind (pop) rivets. I checked and just barely had enough room to access these rivets with the pneumatic squeezer so I substituted the pop rivets with squeezed solid rivets. Turned out great!

Standard convention when setting a rivet is, if at all possible, place the manufactured head of the rivet on the thinnest material so the shop head gets formed on the thicker material. There are times when this is not desired … case in point, Van’s suggests the manufactured head be placed on the cap side of the rear spar because all the rivets are visible. This creates a small problem … when the rivet sets, the expansion has a tendency to push the thinner material up and away from the thicker material so the riveted parts don’t set flush on one another after the rivet is set. Solution … use a small piece of vinyl tubing 1 1/2 to 2 times the length of the visible portion of the rivet to be squeezed. Slide the tubing over the rivet shaft then squeeze with the squeezer to set the rivet.

The vinyl tube will press down on the thinner material keeping it flush before the rivet begins to set.  Works great! Wish I could say it was my idea, sadly it is not ... it’s a tip I read on a builder support WEB site.

Builder Tip:
When riveting and the shop head must be formed on the thinner material use a piece of vinyl tubing 1 ½ to 2 times longer than the protruding rivet shaft. Slide the piece of tubing over the shaft of the rivet and squeeze. The tubing will be compressed onto the thinner material keeping it flush as the rivet begins to set. Not my original idea but my hat goes off to the wiz kid that thought of that one because it is simple and effective.