Ch 14.1: Center Spar

What I've Been Doing In My Spar Time

I'm skipping Ch. 13, Nose Gear, for now because I don't have my nose gear lift yet.  So, while I figure that out, I thought I'd tackle the center section spar.

The center section spar, along with the canard, is one of the most important parts of the airplane.  Aerodynamically it is responsible for carrying about 80% of the weight of the aircraft when in flight.  The canard lifts the remaining 20%.  It's a box structure made mostly of some lightweight and crazy fragile polyurethane foam, but of course it ends up being one of the strongest parts of the plane.

Completed Jig for the Spar

The spar is built on a jig that must be built first using 3/4" particle board.  The thickness of the board helps to ensure a nice straight jig.  The strange part about building it is that you're building a jig using dimension callouts in the 100ths of an inch, measuring with a tape measure in 10ths of an inch, and cutting with a table saw.  Amazingly, I think I got all the measurements as close as one could reasonably get under those circumstances.

Now it's time to start building the spar itself.

Onward!

Ch 12.2 Canard Mounting - Aligning the Canard

Can I be straight with you?

Let's hope so.  I don't want my Cozy to fly crooked!
The next step is to align the canard properly so the mounting holes can be located and drilled.  This involved matching the center-line (C/L) of the canard to the C/L of the front bulkhead...which if I've done everything correct so far should actually be the C/L of the airplane.  Wouldn't that be great!

Ch 12.1: Canard Mounting

Mounting the canard to the fuselage - Alignment Pins

Yay!...I get to add the first flying surface to the fuselage.  I guess technically it would be the second since I've already fabricated the main gear fairings, which are also airfoils, but this one is more exciting.

Editorial Note:  I know some people following this don't know one part from the next and it's sometimes hard to tell what's going on in my pictures.  So, going forward, I'll try to include a small pic like the one to the right that highlights the part I'm talking about.  Hope that helps.

Ch 11.6: Elevator Mass Balance - Canard Fab Complete

It's All Gotta Balance

The last part of the canard/elevator build is to install the mass balance weights.  Control surfaces have to balance properly to avoid flutter.  Airplane...and especially pilots, don't like flutter!  Here's how we prevent it.

Ch 11.5: Canard Tips

Canard Tips...as in the tips of the canard, not hints for building.

Eureka cut foam tip micro'd in place

With the elevators in place, the canard can now get tips to finish out the ends.  The plans version have a swoop up at the ends that some people don't really like.  A simpler version just rounds off the tips to blend directly into the airfoil.  Unless you do something really weird, it's really about aesthetics here and not aerodynamics.  I think the plans tips give it a little character so I kept to the plans here.