ProCub Rear Fuselage Assembly

Building a ProCub rear fuselage is fun.  It is designed to be very strong, easy to build, very aerodynamic, and self-aligning throughout construction.  With a little effort, you can start a rear fuselage on a Friday evening and have it looking like a rear fuselage by Sunday afternoon.

You’ll need a large flat workspace, some Gorilla glue, a spray water bottle, an exacto knife saw, a foam rasp, and 220 grit sandpaper.  Peel ply may also come in handy for preventing glue from sticking to your workbench.

You will build the rear fuselage upside down.  The top and the bottom have an identical outline, except the top deck foam has a big cutout in it for access to the baggage or fuel compartment.

General notes:  Always prepare surfaces to be glued with sanding.  Always follow label directions on the Gorilla glue bottle.  We like to apply Gorilla glue to one surface, then lightly mist the other surface with water.  It is imperative that Gorilla glue joints get pressure applied to them — this will cause the glue to expand into cracks.  Learn to use the correct amount of Gorilla glue — too much and it goes everywhere (and adds weight).  Too little, and your joint quality is not good.  Properly applied, a Gorilla glue joint is as strong or stronger than the foam it is gluing.

The very first thing to do is to glue the extensions onto the top and bottom planks using Gorilla glue.  Use some ‘peel ply’ to protect your workbench (or floor, in these photos.)

Preparing to glue extensions onto the top and bottom of the rear fuselage on a ProCub.

Preparing to glue extensions onto the top and bottom of the rear fuselage on a ProCub.

After placing the parts together, weights are used to ensure that the planks and extensions do not creep away from each other as the glue expands.

Using weights to prevent the joints from creeping.

Using weights to prevent the joints from creeping.

Here’s a bigger view of the top and bottom foam planks.

Glue extensions on 2

As soon as that glue has set (which it will do in less than 2 hours), we can begin to assemble the entire rear fuselage.  First, remove excess Gorilla glue from the joint we just made, using an Exacto saw or similar tool.  It takes a little practice to figure out how to remove excess glue without gouging the foam, but it can be done.  You may experiment with a razor blade, a sharp pocketknife, or the tool of your choice.  A foam rasp may also help, but be careful not to rough the foam unnecessarily.

Place the top rear fuselage plank on the workbench.  Then we’ll glue the bulkheads in place, one by one.

Glue bulkheads_

First bulkhead resting in place on the ProCub rear fuselage.

Location of the first bulkhead.  BTW, 19" is measured along the centerline, not along the slant edge.

Location of the first bulkhead. BTW, 19″ is measured along the centerline, not along the slant edge.

Now it’s just a matter of gluing it in place.  Remember the correct Gorilla glue technique:  sand first, use the right amount of glue, mist with water, apply lots of pressure.  And now another tip: ensure that the bulkhead does not ‘float’ into another position.  It will try and float (because of the expanding glue) and will move around, even when it has considerable weight stacked on it.  The solution is to pin it with some stiff wire, as soon as it has been glued.  Or watch it like a hawk as the glue sets.  Make sure the bulkheads are absolutely vertical (90 degrees) and absolutely centered from side to side.

Glue bulkheads 4

First bulkhead gluing in place. It may ‘float’, because pins have not been inserted into it to stabilize its placement.

Glue bulkheads 3

Another view of the first bulkhead gluing in progress.

TO BE CONTINUED….

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