Orange Paint, Horiz Stabilizer, Boot Cowl, Windscreen, Gear Leg covers

We painted some more parts Ocala orange in our paint booth, including two side fuselage foot-well panels, 1 inspection cover, and 2 aluminum gear leg covers.

Orange paint sprayed on 5 parts

The horizontal stabilizers were inserted into horizontal tubes in the tail and bolted in place.  The flying wires for the horiz. stabilizers were also installed and all bolts torqued as required.

Installing a horiz. stabilizer

Flying wires attached

The boot cowl was installed, and the windshield was set in place.  Next screws were installed along the front through the boot cowl and holds the lower edge of the windshield in place.

Boot cowl installed; Line of screws along bottom of windscreen

We attached the (orange) gear leg covers on the bottom of the fuselage.   

Attaching gear leg covers

Right gear leg cover. Finish is nice and shiny.

The front and rear windshield brackets were installed with stainless rivets. 

Rear windshield bracket installed (with "Experimental" lettering)

Finally, we temporarily attached the footwell panels so that we could see how the overall paint scheme looks and make sure everything lines up right. Here is a nice shot of the airplane with the cowling and panels in place.  We still have some blue protective tape on some parts, and are likely adding a stripe at the border between the orange and white.  Very happy with how it's looking so far.  Hours: 21

Nice side shot of airplane with painted parts in place

Leak fixes, Cowl, Door frames, Control sticks

 After last engine runup, we had found we had 2 leaks, one from the brakes and one from fuel.  The brake leak was at the bottom of the Grove landing gear at a right angle fitting. The brakes were drained, and the wheel was removed to get access to the fitting.  The right angle fitting was then removed and cleaned.  Locktite thread sealer was applied, and the fitting was installed with an extra turn to ensure it fit snugly. 

Brake fitting tightened

The fuel leak was coming from a fitting that went from a T-fitting near the fuel filter to our fuel-pressure-sender.  This one was a bit complex because of all the interconnected fittings and hoses.  But this gave us a good opportunity to change our fuel-bypass orifice as we learned ours was slightly oversized ( The ideal orifice size was 0.35 mm, and ours was about 0.88 mm).  Our orifice fitting came from JEGS, and is essentially a hole drilled in a set screw, which is then screwed into a special AN fitting.  Using a small mill with a tiny drill bit, a 0.35mm hole was drilled in the center of a new stainless set screw.  This took several attempts as the tiny drill bits were easy to break, but we got it done.  The new orifice was installed, and the leaks were addressed.  After the fixes, we ran the fuel pumps (which boosts the system to 50 PSI) and checked for leaks again.  None were detected. 

Fuel leak fixed at this T-fitting

The new 0.35mm fuel-bypass orifice is in the top of this T-fitting

The cowl pieces, which had been previously primed, were sanded down with 320 grit sandpaper so that they will be ready for painting, although we won't get to that until the paint booth is back in working order.

Next we turned our attention to the doors.  We previously made a couple of center aluminum strips that cover the seam where twoLexan panels meet.  We wanted to close up the ends of these, so we filled them in with a little bit of epoxy (JB-Weld) which was sanded flat once dry.  This is mainly cosmetic, but does make it look a little nicer when installed. These strips were also sanded lightly to get them ready for priming.

Epoxy added at the ends of center door frame strips

We also wanted to decide on the color to paint the door frames.  We were originally thinking of using gray as that matched most of the interior and existing powder coat, but also considered black as that helps create more of an unobstructed view out of the airplane.  We wrapped the frame in some spare black vinyl we had to get an idea of how it would look.  We liked the result, so we will likely paint the door frames black now. 

Experimenting with black door frames

Lastly, we drilled a couple of small holes in our control sticks for the wires that will go to the push-to-talk switches.  We are going to making the control sticks removable, so plan to add a small connector that will make the wires easy to disconnect.   Hours: 27

Hole drilled in control stick

Engine test #2, more Cowl work, and misc

We had a run of nice weather, so decided to prep the plane for another ground run.  We bolted the propeller back on, carefully setting the pitch of each blade to keep them within 0.3 degrees of each other.  We decided to keep the cowling on for this test since we had just finished installing the Skybolt fasteners in them.

This time we ran the engine for a longer test period (about 15 minutes), and also ran up briefly at full power to verify the prop pitch.  At full power, our engine RPM needed to fall between 5100 and 5800 RPM to ensure the blade pitch is within limits and safe to fly (per guidance from our prop manufacturer, E-Props).  Ours came up to 5200, so it is good.  We may need to change the prop pitch a bit later once we get to the flight testing stage.  E-Props recommends pitching for 5500 RPM when in flight at full power.

Michael behind the controls for the 2nd engine test run

The test run went well, although we did uncover a few issues after looking everything over after the test run.  We found some drips down by the right brakes, and found two brake fittings that had drips and need to be addressed.  We also found a bit of fuel leaking around the fuel pressure sensor that we will fix.  This shows how important these early tests are as they help flush out these type of issues.  Some brake line compression fittings and a few new fuel hose fittings were ordered and will be installed once they arrive. 

We also did some additional work on the cowling to improve the surface finish.  This included adding a little more filler and sanding. The front ledge of the boot cowling was also trimmed back a bit (about an inch). We decided to shoot a light coat of primer on the three cowling pieces, as this can help to find remaining defects in fiberglass.  We did this outside since our paint booth is currently full of tools and parts.  Not sure why this works so well, but just this little coat of primer really did help highlight some of the remaining irregularities in the surface that we will now fix.  

Light coat of primer on the three cowling pieces

We also wanted to address the cockpit down tubes that are directly in front of the pilot and passenger.  We decided to wrap them with a matte black vinyl to hopefully help mitigate reflections on the windscreen. A 2" wide strip of vinyl perfectly went around the circumference of the two tubes. Hours: 21

Black matte vinyl added to down tubes

 

Misc (Brakes, Cowl, Header Tank)

We've been working on a lot of various parts over the last few days.  We finally got all the brake plumbing complete and got the brake fluid bled. It took some effort to remove all the air bubbles.

The front of the cowl received 3 layers of fiberglass over the foam shape in near the propeller.  After allowing the epoxy to cure a lot of sanding was done to smooth the transition.  We're planning on adding fasteners on the inside of the cowl air openings hear the propeller hub.  This area needed some attention with fiberglass to give enough room for fasteners.

To make the site tube more visible on the header tank, Ed is fabricating an aluminum shroud that will also have a hash pattern that will greatly improve the header tank level.  This is just a back-up since we also have a fuel level sensor on tank that turns on a red LED on the dash if the level ever drops below a set value.

Hours: 8

Peel-ply over the top of the fiberglass addition on the upper cowl

Fixing the lower cowl to allow for fasteners

West System epoxy in use

Ed working on header tank site gauge shroud

Carpet, Fuel lines, Brake system

We had to make some small adjustments to a floor carpet piece that we received from the factory due to some fittings under the seats that were in the way, so Michael put his sewing skills to use to trim and restitch the carpeting.

Michael modifying the floor carpeting

Various clamps holding the fuel lines were checked and torqued, then the fuel line fittings themselves were also torqued and marked with "torque-seal".  A low-pressure test was run on the system (from the header tank to the engine) to look for possible leaks.  The system was pressurized slightly with air, and it is indeed leaking, as it loses about 5psi of pressure over 5 minutes, so more investigation is required to track this down.

As mentioned in a previous post, we decided to remove the parking brake, so the parking brake cable, valve and all associated cabling and tubing was removed.  A nice black plug was installed in the panel where the parking brake lever was previously located.

The left brake had previously been bled, but it has a slow leak at an elbow fitting near the tire.  This fitting needs to be "clocked" correctly, but we found that one more turn to tighten it more was not possible.  After some research, we found a few possible solutions.  One is to use a better thread sealant (now on order), another is to use a new fitting that will have slightly different threads that will allow the correct clocking, and yet another possibility is to tap the threads a little more to allow the fitting to turn a little further.  So we'll try one or more of these options to fix this issue.   Hours: 12

Battery vent, brakes, wiring

The battery vent hose routing was completed.  This directs any unwanted gases from the battery out the airplane in the unlikely event of a (lithium) battery failure.

Battery vent tubing installed

More wiring bundling and cleanup was completed.  We are pretty much done with the wiring now until we get the chance to put the wings back on, in which case we will wire up the navigation lights and magnetometer.

Wire bundling behind the instrument panel

Wires bundled and routed behind pedals

Wire bundling in back of airplane

We ran into a few issues with the brakes.  When attempting to bleed the brakes, we found some problems.  One is that the parking brake valve was reversed.  This was corrected.  But then we realized an issue that we should have found sooner.  Our brakes have 2 master cylinders, one attached to the backside of each of the pilot's pedals.  The top of the master cylinders need to be at the highest point in the hydraulic system because they have an integrated resevoir for the brake system.  Unfortunately this was not the case because our parking brake valve sits much higher on the firewall.  We figured there are 2 ways to fix this.  Either change the brake system to add an auxiliary resevoir at a higher point (also requires us to change 2 cylinders), or just remove the parking brake.  To keep the parking brake, we figured we'd have to spend another $500 or so, and add more weight.  This didn't seem worth it since the parking brake is not required, so we decided to remove the parking brake.  Kind of a pity since so much time was spent on this, but we both think this is the best decision in the end.  We can always add it back later if we change our minds.

Michael bleeding the brakes

Lastly,  four nutserts were installed for the fuel on/off switch.  This will allow us to install the plate with simple 8-32 screws instead of the sheetmetal screws that were part of the original plans.  Hours: 20

Brakes and Panel

Finally got the parts in to finish installing the brakes.  We needed a 90 degree fitting on the landing gear and a straight fitting on the brake caliper.  The 10" hose fit perfectly and made for a nice clean installation.

Brake Line Installed

A lot of time was spent laying out the instrument panel and we're closing in on our final design.  We've started doing our wiring diagram (in KiCAD) and this will help us determine how many circuit breakers and switches we need.

Most recent Panel layout

Hours: 8

Fuel system work, landing gear covers

Made a small modification to our header tank to optimize the fuel return for our fuel-injected engine.  We welded on another AN6 bung a little further down from the top of the header tank which allows us to locate the fuel return a bit lower.  This allows any returning fuel vapor to cool and condense before rising and venting to the wing. 

After welding, a 24 hour pressure test at 9psi was run and it lost a little pressure.  With soapy water, I found a slow pinhole leak.  The pinhole was welded closed and the tank was retested.   This time it held pressure for 24 hours, so the problem was fixed.

Pressure test on header tank

Planned out some of the fuel line routing, and installed a fuel shut-off valve.  

Two mounting brackets and a tray were fabricated for mounting the Rotax fuel pumps.  The tray was riveted to the brackets and the brackets were installed with Adel clamps.

Fuel pumps installed

A few small nose-gear spacers were painted gloss black, and the nose gear was reassembled.

Two covers were also created to enclose the landing gear holes in the bottom of the fuselage.  The back edge required a slight bend to match the profile of the fuselage.  Holes were drilled to match the existing nut plates that were previously installed in the lower support tubing. These came out looking nice.  Hours: 24

Aluminum cover for landing gear (2 were made)

Fuselage unwrapping, Side panels, Baggage door hinge

We finally removed all masking and protective wrap from the fuselage and got a good look at the two-tone paint job.   Looks great and we are very happy with the results.  We are planning on adding a 1" stripe between the white and orange, but that won't be applied until later.

 

We installed the landing gear brackets, and had planned on immediately installing the landing gear so that we could get the plane on wheels again, but ran into a minor issue.  The bolts we have on hand are slightly too short.  We ordered some longer bolts and will install it when they arrive.

In the meantime, we decided to install rivnuts (rivet nuts) for the front aluminum panels located on the front-sides of the fuselage.  We up-drilled holes in several (24) of the steel fuselage tabs to accept the rivnuts, deburred the holes, and then installed the rivnuts with a puller.  We also added a little epoxy when installing the rivnuts which was a recommendation we got from Kitplanes magazine.  This will make them much less likely to fail (break free and spin) in the future.  Hours: 5

RivNut installed in the metal tabs

Next, we riveted on the hinge for the baggage door that we had previously fabricated. 

Hours: 5.0

Hinge riveted to fuselage

Landing Gear and Mounts are Orange

 We laid down a coat of orange on the Grove landing gear and the mounts for the gear.  We sanded them lightly the next day, and followed that up with another coat of orange.  Very happy with how they came out..they are looking pretty sharp with a couple coats of Ocala orange. Hours: 5

Gear and mounts painted

Epoxy Priming Main Landing Gear and Gear Mounts

We received our packet from Aircraft Spruce containing AlumiPrep and a new quart of Superflite Epoxy Primer and Catalyst.  Each of the parts were cleaned with AlumiPrep cleaner and then flooded with water to neutralize the cleaner.  The parts were wiped dry, all holes were dried with compressed air.  Our final step was to wipe the parts with Isopropyl Alcohol.  The all parts were painted with the Superflite Epoxy Primer and allowed to dry overnight.  We lightly sanded the parts with a Grey Scotchbrite pad and inspected the parts for coverage.  The main gear looked adequately covered, but the smaller parts had some areas that needed a second coat so we wiped them down again with Isopropyl Alcohol and sprayed another coat of Epoxy Primer.

After another day to dry, the parts were lightly sanded again with grey Scotchbrite and inspected.  The parts are now ready for their final top coat of Ocala Orange paint.

Hours: 4.5

Parts in their nice white Epoxy Primer

Fabric covering of landing gear opening

We are in the process of covering the area around the landing gear, primarily for the purposes of prevening air infiltration around the openings for the Grove landing gear.    We first attached a flat piece that will sit right above the landing gear (using Superflite U500 adhesive) and shrunk it in stages until nice and taut.

 Next we started working on the two angled side pieces.  These pieces are much trickier because of all the strange shapes and protrusions, and everything seems to get in the way (including the floor for the baggage area)... but we have an approach that seems to be working and have made some good progress.  The fabric for those side pieces has been cut to shape and mostly glued into place. We still need to take out some wrinkles before shrinking the fabric.
Hours: 7

Fabric work around landing gear area

Fabric work around landing gear area II

Landing Gear Area Covering

We've mentioned before that since we decided to use the Grove landing gear it has caused a few issues with our build and it's not documented in the Just Aircraft Builder's manual.  Since the gear will pass through the bottom fabric, we needed to control air infiltration through the openings.  In previous Blog postings we showed pictures of the additional elements we added to support the Grove landing gear.  No we are starting to add the fabric that will enclose the gear area preventing cold air from getting into the cockpit.  We added three coats of the U500 adhesive to the area in preparation of adding the fabric.  Hours: 2

Landing Gear Opening

We continued to work prepping the fuselage for covering.  Two fore/aft members were added onto the sideways members added previously.  This is forming the opening in the fabric that will allow us to pass the Grove landing gear through the covered fuselage.  Two 1/2" aluminum tubes were machined on the metal mill to tightly fit.  After the areas were roughened and cleaned with acetone, they were epoxied in place with the Hysol epoxy.

1/2" aluminum tubes epoxied in place

Computer Edited to show opening size

We also checked over the fuselage and found quite a few locations that had finish pits.  We cleaned the rust from these areas and applied epoxy primer that matched the Gray paint color.  There were a LOT of areas that needed touch-up.  Hours: 3

Fuel System Redo and Land Gear Fabric Work Thoughts

Wow,  now that the fuselage is back in the garage Ed and I have been giving a lot of  thought on various things.  First, we were never happy withe the flares on the fuel line runs so we decided to buy a new, highly recommended, fuel line flare tool.  We removed all the old fuel line and started running the new fuel lines.  But after some more thought, we are now planning on a more radical change in the fuel line routing and incorporating the Andair gascolator into the run.  We are currently in the planning stages on the new runs.

We are also thinking about adding a baggage door to the side of the fuselage.  Since the baggage area is so deep, having a side access door has been highly recommended by other Highlander/SuperSTOL builders. Like the new fuel routing we are currently in the planning stages on this.

And finally, we knew this was coming and the "kinda" planned a little, but we now need to give serious thought on how the fabric will be done in the area of the landing gear.  Access holes though the fuselage will need to be made so the solid Grove landing gear can be rune through the fuselage.  The mounting bracket for the gear is causing a lot of grief.  We've how come to the conclusion that some additional non-structural parts will need to be added to support the fabric work.  Then once the fabric work is done, some type of fairing will need to be constructed to cover up the holes.  We are also concerned about cold air infiltration, so that is going to take some more thought to overcome.

So not a lot of physical work was done, but a lot of time has been put into this effort.  Hours: 4

Some additional structure being considered

Prototyping structure with fuel line and hot glue

Landing Gear Dolly

The garage is getting little crowded.  We are getting close to the point where we will need to attach the wings to the fuselage, so we were needing a way to move the whole project around the garage.  To allow this, a dolly needed to be constructed under each main landing gear wheel.  A quick prototype was made as a proof of concept.  The final version will be more wheel friendly, but the prototype seems to work great.  Hours: 1

Landing Gear Wheel Dolly Prototype

Nose gear

The front nose gear was assembled.  The spacers on each side of the axle bolt that came with our kit were too short (possibly sized for the Escapade, and not the Highlander wheel).  New spacers were fabricated to fit our nose wheel, and the lengths were 2 1/4" on one side, and 2 7/16" on the other side.  With these new spacers, the fork legs were held tightly against the spacers, which were in turn held tight against the wheel bearing as required.

Nose wheel with new spacers

The nose wheel fork assembly was then fitted onto the shaft of the nose gear leg.  The friction bushing (part F-3590.3) that was supplied with the kit was previously found to have an opening that was too small, but a new part was quickly obtained (thanks Amazon), and fit perfectly.  The nut had to be tightened to the point where it took at least 20 lbs of force to move the fork assembly.  This was measured (as recommended per the manual) with a scale attached to the fork near the axle.   Once 20lbs was achieved, the nut was rotated just far enough to get the hole in the nut to line up for a cotter pin.  We remeasured the force again to see exactly how many lbs of force were then required to move the wheel, and it came out a bit over 23 lbs.

Point where fork just begins to rotate (20 lbs, 2 oz)

Point where fork rotates after nut aligned and cotter pin attached (23 lbs, 13 oz)

Once the nose gear was attached, the back of the plane was raised slightly with the rear rotisserie point so that the airplane was sitting on all 3 wheels  (A rear attach point is still currently needed because the plane is tail-heavy without an engine).  Hours: 2

Image of Fuselage sitting for 1st time on 3 wheels

Additional Nose Gear Work

The fitting of the pin on the Nose Gear was finally completed.  A couple of the oil sintered brass bushings had to be reamed to allow the pin to fit correctly.  The nose gear firewall attachment segment in the builder's manual is a little out dated.  Looks like the factory has changed the design without updating the builders manual.  With the parts provided, we were able to figure out the new design.  Here's a picture of the finished installation.

Nose Gear Firewall Attach Block and Pin

The suspension pin F-3450 was attached to the top of the gear leg using an AN4-14 bolt and associated hardware.  We had added the rubber shock absorbers and washers to the suspension pin earlier and attached it to the nose wheel mounting frame, F-3400.

We started to attach the nose gear fork assembly (F-3570.4).  Again the two oil sintered brass bushings had to be reamed to allow the fork assembly to be installed.  We ran into a part issue. The F-3590.3 friction bushing supplied has a much smaller hole than required for installation. To make the part work, we would need to make the inner hole 1-1/4".  We decided to order a Thrust Bearing Washer from Amazon with the same thickness and inner diameter, but a slightly larger outer diameter.  Should be here in a few days.  Hours: 3.0