Airworthiness Cert, Vortex Generators, Rigging Check, High speed taxi test

We finally received our airworthiness certificate on Aug 20, but had some work to do before first flight.  During our trip to Brasstown for transition training, our flight instructor (Vic) at Plane Fun Aircraft gave us many tips, and strongly recommended that we add vortex generators (VGs) before first flight.  These should lower stall speed a bit and they reportedly do not affect top speed.  We originally planned on adding them post flight to gauge their effectiveness, but changed our minds after talking to him.

The VGs that came with our kit had sharp corners and no adhesive (they recommended a form of super glue).  We elected to order some new ones (Stolspeed VGs) as these had a more rounded shape and came with 3M adhesive that is removable.  We installed them per instructions.  The VGs at the wing tips are installed with a closer spacing to ensure the wing tips stall after the root wing stalls.  We also installed VGs on the bottom of the horizontal stabilizers.

VGs on the wing

VGs on horizontal stabilizer

Also, even though our wings were rigged at the factory, we were advised to double check this   According to Vic, If the wing is leveled at the root, and measures something like -1 or -1.5 degree angle at the center (angle of incidence), then it should be about -2 to -3 degrees at the wing tip.  Having a little twist like helps ensure that the wing tips will stall after the main wing stalls. More important is to ensure that both wings are identical.  When we measured our wings, we found that the right wing was close to level across the whole span (no twist).  The left wing was a little better but had just -0.8 degrees at the tip.  We adjusted the right wing as far as allowed by loosening the jury strut and then rotating the main strut's clevis fork rod end, and were able to get it to -1.2 degrees at the tip (with about 0.6 degrees center).  The left wing was then adjusted to match this. 

We also ran another taxi test.  This time it was a higher speed taxi test down the runway.  Power was applied gradually while holding back the stick until the nose lifted off the ground, then reduced to hold the position.   The test went well, although we noted that the airspeed on our Garmin G3x never dropped under 23 MPH.  We contacted Garmin and found that this means we need to have our GSU25c (ADAHRS) replaced.  Luckily, this will be covered under warranty.  

We are also finding that our coolant temps still run a little high during taxi on hot days so we may need to adjust the cowling opening and/or radiator position sometime in the future to improve this.

Fuel tests, flaps, misc prep

 We've been taking care of various miscellaneous things to get ready for inspection.  We performed several fuel tests to determine the unsuable fuel as well as total fuel for our airplane.  Each of the fiberglass wing tanks hold 12.5 gallons, the header tank holds 2.3 gallons.  The unusable fuel in the header is just 8 oz, and the unusable fuel in each of the wing tanks is about 1/2 gallon.   

During the tests, we found that our low fuel detection system was not working.  After some debug, we determined that the sensor itself was bad, so ordered a new one and replaced it. The new sensor is working and our bingo fuel detection is once again up and running.

Bad fuel sensor that was replaced

Fuel flow tests were performed with the airplane in level attitude (which is the critical attitude for this plane), and also tail low (corresponds to nose 15 degrees high).   Tests with individual fuel pumps running, and both running were performed.  Even with minimum fuel, fuel flow through the system was always above 24 GPH  which was very good since our minimum requirement is 9.25 GPH (125% of max fuel consumption).

Fuel was added a bit at a time so we could determine markings of fuel level.  Fuel levels are visible through the fiberglass tanks, so adding markings will give us an approximate fuel level.  A label with markings will be made that will be glued to the tank.

Detailed Fuel flow data is shown below:

We found that our flaps were rubbing a little bit on the flap gap seal in some areas, so carefully bent the edge of the flap gap seals to prevent this from happening.

Wear mark on flap shows where flap gap seal was rubbing

We also adjusted the routing of a wires in the engine bay to avoid potential rubbing, and wire-tied the heater hose valve in place.  Hours: 15

Flap gap seals, Fuel lines

Now that the flaps are finally installed, we decided to install the flap gap seals, which are aluminum strips that span the gap between the wing and the flaps.  We had previously primed and painted these pieces, so all we had to do was rivet them to the wings.

Flap gap seals installed

More time was spent planning out the fuel lines from the wings to the header tank. The wings were folded several times during this process as we need to ensure that the hose routing and hose lengths will accommodate folding of the wings.  Hose ends were attached to complete two of the hoses that run to the header tank.  We are waiting on parts to finish the remaining hoses.

Right angle connectors installed on upper hoses

Additionally, work has started on installation of the rear baggage panels.  We found that a few attachment holes that were drilled into these panels no longer line up with the holes in the chassis tabs.  This may have been due to flexing of the tubes that occurred when shrinking the fuselage fabric.  We may just remake that panel as we have some spare aluminum sheet.

Work is also underway on installation of the glare-shield.  Some right angle brackets were made to help support the glare-shield along the front edge.   Hours: 9

Fairings, Wing wiring, Flap hinges, AOA tubing, Seatbelts, Fuel lines, Door latches

 A couple of fiberglass fairings were trimmed to fit.  These fairings connect the butt rib to the windshield and clean up the area there.  Attachment holes were drilled in the fairing and the windshield using a drill bit for plastic.  After trimming, pinholes in the fiberglass pieces were filled with dry-micro.

Fitting of fiberglass root-wing fairings

The navigation and beacon lights were installed in the wing tips and wired up to the switches in the panel.  A minor mistake was made by wiring up the green light to the pilot side wing, but quickly found this during test and swapped the lights so they were correct.  

Michael labeling wires for the Nav. lights

Previously we mentioned that the flaps had too much friction, so we reamed out the bushing holes slightly, and also found some paint overspray in wing holes that we reamed out.  After this work, the flaps now function nicely.

Flap hinge works great now

The door latches were painted a flat black (using plasti-dip paint) and one of them (previously drilled) was attached to the door.  The strut-attach brackets were also painted.

Door latch painted flat black and attached

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Strut attach brackets

We ran into an issue with the tubing for the AOA line (which is run adjacent to the pitot line).  While working on the routing of these tubes along with the fuel lines from the wings, the blue AOA line got pinched when attempting to fold the wings, which tore a nice hole in the tubing.  We will repair this and adjust the routing to prevent this from happening again.  

Blue AOA tubing with a tear

Seatbelts were installed and and all seatbelts torqued down.

Michael installing seat belts

We opened up the rear slot in tje butt-rib (using a dremel tool with sanding bit) to allow for the fuel fittings to rotate into position when the wings are folded/unfolded.  Hours: 28

Fuel line for right wing

Ed checking fuel line routing while closing wing

Plane relocation, plus work on flaps, wiring, fairings

 In prep for moving our plane to Sanford (TTA), we completed fabrication of travel struts.  Two rear struts had previously been made, but we made a couple of front struts that attach from a landing gear mount to the spar tube.  This adds some support when the wings are folded and make it safer for travel.  

Front travel strut attached

We actually unfolded the wings to load the plane on the trailer as this keeps the center of gravity forward of the main gear.  Once the plane was on the trailer and the front tied down, we folded the wings back and installed the travel struts.  We then finished tying it down and successfully transported it to Sanford.  This was a big accomplishment as this is the first time we trailered it with wings folded.  This is the airport where we will be performing our initial test flights.

Removing travel struts after towing

Wing unfolding

Plane at new home

Some other work we did on the airplane is listed below: 

A thin plastic corrugated tube was inserted through the front spar of each wing for use as a protective conduit for wiring.  Wires were routed through these tubes in prep for wiring up the wingtip lights.

The flap pulleys were installed and torqued down.  The flab cables were fabricated and installed.  We ran into a problem on the right wing as the flap wire had inadvertently wrapped around the aileron cable, which probably happened sometime during the paint process.  This was easy to fix as we just removed one pulley and had enough room to fish the wire back where it was supposed to go.

The flaps were tested and we found that there is too much friction in the system, as the flap spring couldn't always pull the flaps all the way back up when retracted.  After further investigation, we found that some of the bushings are not rotating freely, so we will need to ream out the holes just a tiny bit more to enable these to work correctly. 

An aluminum fairing was made to cover the gap between the fuselage and butt rib.  Holes were drilled and clecos installed.  This will be painted before final installation.

Some work was started on some fiberglass fairings that cover the area between the butt ribswing and windshield.  The right fairing was trimmed a bit, but more work still needs to be done on this.  Hours: 30

Travel Struts, Folding Wings, Trim Connector

Now that we have complete wings that are attached, we found a problem when we went to fold the wings.  There was some interference with the back of the root rib.  This was fixed by trimming the edge of the butt ribs and also trimming a little bit of the plexiglass sunroof.  The wings fold very nicely now.

Butt rib and plexi trimmed

Wings folded after interference fixed

Two rear travel struts were fabricated.  When the wings are folded, these struts pin the wings to the tail to prevent them from moving while towing.  Work has aslo begun on two additional front travel struts.  Brackets were made from angle steel that will attach to landing gear bolts and will be the lower attach point for those struts.

Rear travel struts (gray)

A 4-wire connector, located at the bottom of the tail, was installed on the power and control wires for the trim motor. It was secured with cable ties, which was not a trivial task due to the limited access.  Function was tested and the trim motor moves as expected when the trim buttons are pressed. 

Hours: 18

Aileron, ELT, Pitot, Jury Struts, and Turtledeck

Michael installed the green vinyl strips on on the wings.  This allowed us to then install both of the ailerons.  Once that was done the control cables were re-attached at each of the control horns on the flaps and ailerons.

We had to obtain a new battery for our ELT since the original had exceeded it's expiration date.  A new battery was obtained and the ELT was re-installed into its cradle in the tail of the airplane.

New ELT Battery

Ed started working on the turtledeck modifications that are needed to allow the control cables to enter the cabin area.  A lot of precise measurements needed to be made before determining the location of the holes.

The pitot/AOA probe was installed onto its mounting stalk.  This required cutting down and deburring the probe tubes and trimming the hoses to the required length before connecting with air-tight push-on connectors.  The green hose is for pitot ram air and the blue hose is for the AOA probe.

Connecting the pitot/AOA probe

Pitot/AOA probe installed

The jury strut to main strut attach brackets needed to drilled and painted.  Once that was complete the jury struts were installed.  Michael tried various ways to  install the jury struts but found that installing them on the main strut first and then attaching them to the wing was the easiest method.  The jury struts were moved around until the main strut was straight (i.e. no bowing up or down) and then the bolts were torqued to their final value.

Left side jury strut installed

Right side jury strut installed

Starting to look like an airplane!

Hours: 8

Flaps, elevators, and jury strut

We brought more parts to the airport, and started working on various things.  The window on one door was trimmed a bit in one corner to eliminate some interference.  Green striping tape was installed on most of the control surfaces where the orange paint borders white paint.  We still need to apply the tape to the cowl and rudder.  The flaps were installed on the wings which was a nice accomplishment.

Flap installed on right wing (no aileron yet)

Michael spent a bit of time adjusting the jury struts and their brackets.  The brackets didn't fit our lift strut very well, so took some bending and persuading to fit better.  These brackets were then removed so that they could be painted white.

Michael working on the lift struts

The elevators were attached to the tail.  The two elevators are bolted together inside the tail, and are installed on their hinges with clevis pins that are held in place with cotter pins.  It felt good to get another control surface attached to the plane.  Hours: 20

Ed installing a cotter pin for the elevators

Wings attached!

We achieved another milestone by getting both wings attached to the airplane.  Rain was pouring down when we were about to hang the second wing.  We had to wait until the rain let up because the rain pelting the metal roof created so much noise that we couldn't hear each other speak.  But in the end we got both wings installed successfully. 

Wings installed.  Happy Builders.

We then installed an aluminum cap strip across the gap between the windshield and sunroof.  We had attached some thin neoprene gasket to the underside of the strip before installing to help keep it weather tight.

Next, we adjusted the newly vented fuel caps so that they fit snugly in the tanks, and inserted them into the empty fuel ports at the top of each wing.  Hours: 8

Vented fuel caps inserted

Tank cleanout, Windscreen work, Stripe, Fuel cap

To clean out the fiberglass fuel tanks and also ensure there is no uncured resin, we used the clean-out method recommended by the factory.  Basically,  add 1 gallon of lacquer thinner to the tank (ensuring all openings are sealed), swish around in the wing while turning and tilting it to ensure all surfaces of the tank get wet (about 30-40 seconds), then remove cap to release pressure as it builds quickly.  Drain and repeat with 2nd gallon.  Drained fluid should be clearer.  Drain and repeat with 3rd gallon.  This 3rd gallon comes out clear, so it is saved for use on the 2nd wing.  This process was then repeated on the 2nd wing.  A total of 5 gallons of lacquer thinner was required using this method. 

Michael sealing fuel port in prep for fuel tank cleanout

During a final test fit of the windshield, we found that some of the attachment screws could catch the sides of the holes in the windscreen.  Since this could lead to eventual cracking of the windshield, we carefully enlargened the holes for better clearance by using a Dremel tool with a cylindrical bit.

A few holes in plastic windscreen enlargened

A green stripe (3M light green material) was applied to the side of the fuselage between the white and orange paint.  We like the look and plan on adding this stripe material to the wings, cowl, and control surfaces that have both orange and white.

Green stripe added to sides of fuselage

The fuel caps need to be vented, so we disassembled the fuel cap and drilled a 3/16" hole in the top and bottom sections of each fuel cap.  We then upsized the hole to 1/4" in the upper fuel cap, but only to half the depth.  The fuel vent tubes were cleaned and epoxied into the 1/4 inch holes.

Hole drilled in top of fuel cap

Vent tubes epoxied into the fuel caps

We decided to spray black Plasti-dip on the seat position latch handles.  After masking off most of the base, the T-handles were sprayed with about 6 coats.  Hours: 13

Plasti-dip on seat position latch handles

Wing and Fuselage Transport

 Another big day.  We carefully loaded up our newly painted wings onto a trailer, secured them in place with some straps, and transported them to the airport.  This gets them out of way so that we can start painting the fuselage.  Once at the hangar, we set them in a wing-sling and then covered them with some plastic for a little added protection. 

Wings loaded onto the trailer

Removing some residual masking tape

Wings secured in place with straps

 Ed & Mike in the hangar with the wings

Next we loaded up the fuselage for transport back to the home workshop/paint-booth. 

Loading the fuselage onto the trailer

Fuselage on its way to the paint room

We tucked the fuselage into the paint booth, and it does fit nicely.  We will actually be taking it off the gear again and putting it back on the rotisserie before painting.  Hours: 8

Fuselage back in paint room

Right Wing painting complete

 We sanded/polished a small section of the wingtip to fix a blemish in the orange.  We then removed the masking that was over the white section, and noticed one area where some orange had snuck around the masking and made a small splotch on the white portion of the wing.  There had to have been either a small tear in the masking plastic, or perhaps a small area where the masking tape peeled up.  That was annoying, but not a big deal to fix.  I sanded the splotches with 1000 grit until the orange was gone, then moved up to 2000 and 3000 grit... and then buffed with polishing compound to get back the shine.   We also had a small paint issue around the fuel filler cap where the white paint peeled up a bit with the masking tape.  We fixed this with a little bit of touch-up paint.  Hours: 4

Right wing painting completed

Touching up a small spot around filler cap

 

Painting Right Wing

 We masked off the right wing tip and painted the wing white, then once dried, masked off the white portion and painted the wingtip orange.  This is the same process we used for the left wing.  It would be easier to just paint the whole wing white and then paint the wingtip orange, but that uses more paint and adds more weight to the wing, so we opted to do this in two steps.  After spraying an orange coat, we immediately remove the strip of masking tape on the border between the orange and white.  This allows the orange paint (while still wet) to flow slightly onto the white to smooth the border (while still keeping a sharp line).  We sprayed 2 coats of orange, sanding between coats.  Before spraying another coat of orange, we reapplied masking tape at the border between white/orange.  This step only takes a few minutes, so is not a big deal and prevents a paint ridge from building up between the white and orange sections.

After the 2nd coat of orange dried, we noticed a decent sized paint defect in the orange on the top surface (an odd globule of paint, perhaps from the paint gun), so Michael shaved off the paint bump using a special razor tool, and we'll sand and polish that out next.  Hours: 9

Re-masking at the white/orange border