CONNECTING AIRFRAME PARTS TOGETHER

By Jim Ruttler, Instrumented Rated Pilot, RV-10 Builder, Patent Attorney
www.ruttlermills.com
jim@ruttlermills.com

As previously discussed, the bulk of the metal work is in the empennage section when you order the quickbuild fuselage and wings.  With the quickbuild options, the fuselage and wings are built for you by Vans Aircraft.  So, with the empennage section complete and the quickbuild wings and fuselage, there is no significant metal work remaining.  I say no significant metal work, but there is some.  Each of the airframe kits are different, but with the larger more complicated RV-10 there is a bottom panel of the wings left off so you can run wiring and hook up the push/pull assemblies.  The fuselage of the RV-10 comes pretty close to complete, but there are some interior panels that are left off so that you can run wires there as well.  Also, the fuselage must be riveted to the tailcone, which involves some additional metal work.

That being said, the next major push with the project is to connect up all of the individual parts and bring the overall aircraft structure to form.  This may seem to be a daunting task, but it is actually quite easy work and the instructions walk you through each step very clearly.  You will need some space and this is the point where you'll want to consider moving the project to a hangar.  Once the airframe is put together, you won't want to take it apart to take it to the airport on the roads. 

The parts are connect using aircraft bolts and nuts or nutplates.  The nutplates are permanent nuts that are riveted to the parts when they are assembled, typically used where it would be difficult to reach a nut.  For parts that move, rod bearings and bolts are used to enable the hinge action.  This is pretty much the same for all of the parts - either bolts or bolts and rod bearings are used to connect virtually everything together.   The nuts are tightened using a torque wrench and the appropriate setting the bolt size, which is given in the instructions.  

Some of the parts need to be connected to the control stick and to the rudder pedals in order to enable movement of those parts from the cockpit by the pilot.  These include the ailerons on the wingtips to enable banking of the aircraft, the elevator on the tail to enable pitch changes of the aircraft, and the rudder on the tail to enable yaw movement of the aircraft (e.g. left and right pointing of the nose).  Again, this would seem to be a difficult task, but it is really quite simple.  For the elevator and the ailerons, there are long rods that travel the length of the tail or the wing and connect up to the control stick.  Movement of the control stick moves these rods which in turn moves the respective elevator or aileron parts.  These rods are visible in the pictures below.  The rudder is even more simple.  It has two cables that travel the length of the fuselage and connect up directly to the pedals.  Movement of the pedals pulls on the cables which moves the rudder.  Deceptively simple.    

Once the parts are connected with the specified bolts and/or rod bearings and the push pull rods are installed, the airframe is essentially complete save for the finishing kit parts and some fiberglass work.

The instructions will help you get the airframe assembled and they are very clear about the steps need to do this.  However, they are lacking when it comes to certain add-on components like wiring, autopilot motors, antennas, and pitot/static port tubing.  I bring these up here because these add-on components are easier to install when the airframe is partially disassembled; yet, the instructions won't give you much help on how to do it.  By the time you figure out what is needed, it is too late and the airframe is already put together.  

The wiring is simple, lay a few guide wires in the wings, below the rear seats to the tail, and to the aft most part of the tail.  This way, you can easily drag any electric or antenna wires you end up needing through the wings and the fuselage without much trouble.  

If you are going to install the Ray Allen trim motors or Dynon autopilot motors, you should mount those before you close up the airframe.  The trim motors are mounted in the wings and in the tailcone.  These motors are covered in the Vans installation manual.  The autopilot motors are mounted in the wings and in the tailcone at different points from the trim motors.  These motors are not covered in the Vans installation guide, but rather are covered in the Dynon intallation instructions.  Getting these motors installed before you close up the aircraft will save you trouble later.

The pitot/static port tubing is also something that should be installed before closing up the aircraft.  Most new builders and even most experienced pilots have no idea what these tubes actually look like or how they are connected.  This was true for me, so I avoided it until the end - big mistake.  Let's be clear, these are just 1/4 inch tubes and there is one for the static port on the side of the aircraft and two for the angle of attack and the airspeed both going to the pitot tube.  All you have to do at this point is lay two 1/4 inch tubes in the wing with the pitot tube.  You can connect them up later, but having them in the wing will save you trouble.  The 1/4 tube for the static port can be left out because it isn't so difficult to reach.  I recommend the SafeAir kit available from Aircraft Spruce.  This kit includes all the plumbing, fittings, and instructions for connecting up these tubes to the respective parts.

After the metal work and the connection of the parts, the airframe really takes shape.  We will next discuss the finishing kit.