Category: Cozy Experimental Aircraft Project

Centre Section Spar

The Cozy MKIV centre section spar joins the wings to the fuselage. The center section spar is the heart of the wing structure.  The top of the spar is flat and the spar sweeps aft and the bottom has positive dihedral so that the fuel runs inboard while in level flight.

We did a trial fit of the spar with the fuselage and need to sand a few rough edges on the fuselage to get a better fit.

After a bit of sanding the spar rough fit into the fuselage.

The spar was moved back to the worktable and all outside surfaces were sanded.

Removed a small amount of foam from the outboard holes on the bottom of the spar. Mixed a small batch of dry micro and applied it to both holes to protect the foam.

Used the dremel tool to make a small flox corner around both outboard bulkheads CS5 & CS8.

Workshop temperature was 24 deg C and humidity 28%.

A batch of epoxy was mixed up and used to make up some micro as well as a small cup of flox.

Epoxy was brushed onto the existing glass edges of the outboard bulkheads then micro was applied to both bulkheads.

Next, the edges were filled with flox to make flox corners.

One layer of BID cloth was placed on each outboard bulkhead at 45 deg orientation and wetted out with epoxy. Lastly, peel ply was added to both layups.

Removed the peel ply from both outboard bulkheads.

Trimmed the glass edges and sanded the edges to be flush with the spar.

Sanded the inside centre section and vacuumed the inside of the spar.

Canard Wing

Here is a video of the canard fit and functional test.

During transit from Alberta to Ontario the canard wing received some minor damage to the right elevator trailing edge and the left tip fairing.

Loose and damaged pieces were cut away from the right elevator trailing edge where the damage occurred. 1-ply BID cloth was cut to size and taped tightly to the bottom of the damaged area.

A mixture of epoxy consisting of 38g resin and 14g hardner was mixed and some of it was used to make a small batch of dry micro. Workshop temperature was 23 deg C and humidity 53%.

The damaged area was filled with dry micro and the BID cloth was then tightly taped to the top surface. The cloth was wet out with epoxy about 1″ back from the damaged area on all sides.

A number of low areas was noticed along the trailing edge of both elevators and so dry micro was added to fill any low areas.

The lower area of the damaged fairing was repaired and held in place with wetted peel ply taped tightly to hold the repaired area in place while it cures. The upper area will be repaired once the lower area cures.

Trimmed and sanded the right elevator repair and sanded other trailing edge rough spots.

More sanding of rough spots along the top side of the canard. Began the left tip repair with a small BID patch on the bottom of the tip over top of a crack. Dry Micro was mixed and low areas were filled in along the canard.

The left tip fairing was filled with micro and clamped in position. Excess micro was wiped away from the sides as the clamps were applied.

The left fairing was sanded on both sides. Dry micro was added to fill some valleys on the bottom side of the fairing. One ply of BID cloth was applied to the back side of the fairing to replace material that is missing.

The right outboard mass balance was detached from the canard when it arrived from Edmonton. I placed wax paper under the existing UNI strap and mixed a small batch of epoxy and dry micro. I added dry micro to replace any missing foam between the foam piece on the mass balance and the foam remaining on the right elevator.

I used a 1″ brush to apply epoxy to the UNI strap and to its interfacing locations on the mass balance and elevator. I used a clamp to hold the mass balance and UNI strap in position during cure. A single layer of BID cloth was applied over the UNI on the elevator to hold the UNI strap in place.

Tightened the two inboard mass balance weights.

Added one layer of UNI cloth to reinforce the right outboard mass balance.

Sanded the bottom side of the canard and added dry micro to smooth over any low points.

Continued sanding the bottom side of the canard, vacuumed the dust and then turned the canard top side up.

Sanded and vacuumed the area to be repaired on the top side of the left fairing.

Applied flox to the edges of the top left fairing and applied a layer of BID cloth and covered it with peel ply.

Removed the peel ply from the left fairing repair.

Trimmed and sanded the left fairing to shape.

Sanded the top side of the canard, vacuumed the dust, and applied dry micro to any low spots on the top side.

Sanded the top side of the canard.

Tested the fit and function of the canard on the fuselage. Verified the elevator balance was sufficient.

Canopy Hinges

The locations for the canopy hinges were marked on the longeron.

Two pieces of MS20001-P6 hinges were cut to10″ lengths.

The hinge halves were separated.

Sanded the bonding surfaces of the hinges and the longeron. 220 grit on the hinges and 36 grit on the longeron.

Tape was applied to the hinges to keep the epoxy out of the hinges.

With the workshop temperature at 24 deg C, a small batch of flox was mixed using 15g resin and 6g hardner.

Flox was applied to the longerons and the hinges were positioned on the longerons and clamped in place such that both hinges are in the same plane.

Drilled #12 holes through the canopy hinges and longeron and countersink.

Installed machine screws, washers, and nuts to secure the two canopy hinges in place.

Cozy Fuselage

1/4” holes drilled and sanded for front and back seat centre safety harness anchor points.

Opened up the 1/4” holes for the landing gear in the forward and aft landing gear bulkheads.

Opened up the 1″ holes in the landing gear bulkheads for the torque tubes.

1” holes opened up in the front seatback – two for the torque tubes and one for the canopy latch mechanism.

1″ holes in the front seatback

Cozy Fuselage Repairs

This Cozy MKIV project arrived recently from Edmonton and consists of many of the main assemblies such as the fuselage, wings, canard, spar, engine mount, canopy, and nose gear.

The project sat idle in a hangar for a number of years after the original builder passed away. The project has some hangar and road rashes needing minor repairs. First up is the fuselage repairs.

The fuselage interior was cleaned up and vacuumed. The right rear electrical channel still had foam in it so that was removed.

The older and loose foam was removed in the areas that were damaged on the top left of the instrument panel and on the left side of bulkhead F28.

New foam and micro was applied to the areas needing repair.

I cut out the bent and delaminated fiberglass and removed the corresponding foam from the front top left of the fuselage.

Foam blocks were placed in the gap and held in place with 5 min epoxy.

The blocks were cut and sanded to shape.

Micro was applied to the foam followed by 2 layers of BID cloth, and peel ply to the interior side of the repair.

There was a hole on the left side of the nose and no ballast compartment. I filled the hole with foam pieces held in place with 5 min epoxy. Next up I will finish shaping the foam, filling in any additional low areas and mark the location where the ballast hatch will be installed.