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

Baggage Door Frame and Gear Opening

We finished carefully cutting and shaping two square and one round aluminum tube to frame the baggage door area.  Afterwards, we cleaned the parts, roughed up the mating areas slightly, and epoxied them into place with Hysol.  Once the epoxy cured a bit, the fillets were smoothed with a wet finger.

Baggage door opening

Close-up of baggage door epoxy joints

Similarly we cut and shaped 4 aluminum tubes that will frame a pass-through opening for the landing gear.  Having this special opening will allow us to easily remove or service the Grove landing gear without removing fabric in the future. We epoxied the tubes between the bottom stringer and the fuselage.

Gear opening tube epoxied b/w the bottom stringer and fuselage

 We still have a few cross-tubes to cut and install to finish off the gear opening, but need to make some measurements and test a mock-up first because we want to make these openings as small as possible, but just large enough to feed the gear through.   In prep for this, we removed the tires and brakes, and put the fuselage back on the rotisserie.  This will allow us to rotate the fuselage around so we can test this out.   Hours: 8

Baggage Door Frame

We've decided to add a baggage door to the aft baggage area.  After much thought and experiments in accessing the most rearward baggage area, we came to the conclusion that getting to that area without a side access door would be most difficult.  We did a search of the WINGSFORUM and FACEBOOK groups to get ideas on how others have implemented the door.  There are so many different implementations and we decided to take the ideas we like and do our own thing.

We will be adding 3 aluminum tubes, two square tubes and one round.   The square tubing will be used to form the outer side opening.  The top longeron and side stringer will form the top and bottom side opening.  The round tubing will form the bottom inner edge of the opening and along with two of the side stringer standoffs it will neatly close off the gap between the baggage area and the outer fabric skin.

The round tubing was cut and ground/filed to shape.  The two square tubing pieces are extremely irregular and is taking quite a long time to get into shape.  We had to restart the two pieces due to an issue getting them to nicely align with fabric.  More works still need to be done getting them to the correct shape/length.  Hours: 5

Left Door

We completed the frame for the left door by repeating the process we used for the right door.  All parts were deburred, cleaned, and the joint areas were lightly scuffed.  The parts were then epoxied and riveted together to form the outer door skeleton.  Hours: 1.5

More Door work

We adjusted all the brackets on the left (pilot-side) door  so that there would be an even gap around the door.  Next, we disassembled the right door, and then deburred, scuffed, and cleaned the separate pieces (tubes and brackets).  We applied epoxy at all the joints before installing the aluminum tubes back on the brackets. We installed one rivet (inside rivet) at each joint, but initially did just a partial pull on the rivets so that all pieces were still a bit loose.  We placed the door back on the fuselage and taped it in place to make sure everything was lined up correctly, and then did the final pull on all the rivets.  Excess epoxy was cleaned up and smoothed.

Moving back to the left (pilot) door, we disassembled it, then deburred and scuffed the ends, and cleaned the pieces.  Still need to epoxy and rivet this other door.

So now we have the frame for the right (passenger) door completed, and are close to completing the frame of the left door.  Hours:  5.0 

Right door riveted and epoxied together

Doors

We started work on the two doors for the plane.  The doors have frames that are made from aluminum tubing which slides over steel corner brackets that were provided by the factory.  The instruction manual did not provide good guidance on building the doors, but luckily there were some good tips already posted on the wingsforum that helped out.  Pictures from several other builders also helped point the way.

To set the gap around the doors, we first taped spacers that were approx 3/16 inch in height to various spots around the fuselage door openings.  We used pieces of tongue depressors as these spacers (a stack of 3, which was close to 3/16 inch).   We taped the door corner pieces in place with painter's tape, and then measured the distances between the corner pieces to determine how long to make the aluminum frame pieces.  We cut several 1/2" aluminum tubes to length, then deburred the ends. The door frames are made primarily from round tubes, except for one piece along the top that is made from square tubing (to accommodate the hinge).

We quickly found that the corner brackets for the door did not quite have the correct angles for a good fit on our fuselage.  After consulting the web, we found that this was a common issue and that "tweaking" (i.e. bending) the corner brackets is needed to get the doors to fit nicely in the openings.  We worked on the passenger door first, bending the brackets as needed so that the angles of the door fit perfectly within the frame.  We had some difficulties with this at first, but then settled on a nice method where we first drilled a hole in a piece of dense wood (we used a piece of Ipe wood left over from a deck project), clamped the wood in a vise, inserted one end of the steel corner bracket into the wood block, inserted a long screwdriver into the other end of the bracket for leverage, and finally bent it slightly as needed.  Several iterations of this process were used until each bracket was bent to the correct shape.

All the brackets for the right (passenger side) door were adjusted for a good fit, but we still have some work to do on the left side.  Hours: 6.0

Michael gently bending one of the corner pieces.

Spacers and alum door tubes held in place with blue tape

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

Air Regulator and Water Seperator

We've been hearing a faint hiss the past few days and it finally grew to a loud hiss.  We noticed that air was coming from the bottom of the water separator where a drain cock was installed.  Upon further investigation it was discovered that the how internals of the unit was corroded and was probably best if we replaced the unit.  A quick order from Amazon and the new (and higher quality) unit arrived and was installed.  Hours: 0  this wasn't airplane project related so no hours counted toward the project time!

Old corroded Harbor Freight Regulator / Air Separator

New Ingersoll Rand Air Filter-Regulator

Bottom Stringer Repair

After removing the bad portion of the bottom stringer, a new piece of 1/2" aluminum tubing was cut to the same length.  A pipe bender was used to (intentionally) bend up one end where it enters the back of the fuselage to match the original profile.  New 5/16" holes were drilled in the stringer for the supports tubes.  Three new stringer support tubes were also made as three of the originals were also damaged (bent) in the incident.

New section of stringer, 3 new support tubes, and inner sleeve

To splice the new stringer to the old one, we used a small 4" section of 7/16" tubing as an inner sleeve (The piece on the left in the image above).  The 7/16" tubing actually had slightly too large of diameter to fit inside, but it also had a fairly thick wall so it was filed and sanded down until it fit nicely inside of the 1/2 inch tubing.  The two sections of stringer were connected together with the sleeve and Hysol epoxy.

The three new support tubes were drilled, deburred, and riveted to the fuselage, and the new stringer was then epoxied to the support tubes with Hysol epoxy.  Looks good as new!  Hours: 5.0

Bottom stringer repair completed

Firewall Forward Worries

Michael has been learning Solidworks (THANKS EAA!) and has been getting the firewall pieces drawn up.  Rotax was nice enough to provide 3D files for the engine and ring mount as well.  The reason we are looking at this with such interest is that we found out recently that there will be an interference issue between the engine mount that Just Aircraft provided and the nose gear support weldment, also provided by Just Aircraft.  In the attached images you can just barely see the interference near the bottom of the engine mount where the ring mount attaches. There is also one other location that will have to be modified as well.  We are still waiting to hear back from Just Aircraft with any recommendations or fixes they might provide.  In the Meantime, we'll continue to investigate all possible alternatives. Hours: 4

Solidworks Engine with Firewall, Engine Mount, Ring Mount, Nose Gear Support, and Rotax 912IS

Bottom stringer repair

As mentioned in the last post, the bottom stringer incurred some damage when we transported it back to the house.  Here's an image that shows the bend in the aluminum tubing.  Two small aluminum support tubes for the stringer were also bent as a result of the incident.

Unnatural bend in stringer.  That's not supposed to be there!

We considered replacing the entire stringer, but then figured it would be simpler to just cut off the rear section that was damaged and splice in a good piece.  The stringer is epoxied to small vertical support tubes, which are riveted to the fuselage.  We cut the back end of the stringer with a pipe-cutter, and then drilled out the rivets on the support tubes.  This allowed us to remove the damaged section of stringer as well as the damaged support tubes.  Hours: 1.5

Damaged section of stringer removed

Transported Fuselage Back to Garage

Having completed the wing covering it was now time to move the fuselage back to the garage.  We've been storing the fuselage in our hangar at Cox Airfield.  We converted a utility trailer into an airplane transport trailer with a winch to pull the fuselage onto the trailer.  A much more controlled way of getting the airplane on the trailer.  The fuselage was securely strapped down and make the 5 mile trip to our home garage.  We did have a small mishap on unloading the fuselage.  We usually have a heavy counter-weight in the front of the fuselage to keep the nose wheel on the ground.  But during the transport the weight was removed for safety reasons.  During the un-strapping of the fuselage, we forgot about the counter-weight being removed and the tail dropped quickly and bent the bottom stringer.  OOPS!  Won't be difficult to repair, but will take some time.  We moved the fuselage into the garage and cleaned up all the straps and put the trailer away.  Hours: 2

Ed and Michael with the Fuselage unloaded

Unloading the Fuselage

Arriving at home base

Fuselage ready to be unloaded

Wing Storage

After completing the fabric covering on the left wing, we hoisted it back up in the shed rafters so that it could keep the right wing company.  Hours: 2.0

Finishing up fabric work on the left wing

We applied more glue to the leading and trailing edges, and then applied a 6" finishing tape on the leading edge, and two 2" tapes on the trailing edge.  These tapes were wrapped around the edges of the wing.  The tapes were ironed in places to eliminate any bubbles and fix them in place. 

We used a soldering iron to burn holes through the fabric at various nut-plate locations, including those for the wing tips, pitot tube, and pulley covers.  We also used razors and X-ACTO knives to carefully cut out the hole for the pitot tube, and slots for the aileron and flap cables. 

Once completed, we noticed that there were a few additional bubbles that had formed on  top of the plastic inspection rings.  Not sure why this happened as there were no bubbles in the fabric after we first installed the rings.  Perhaps we didn't apply enough glue to the top of the rings, although it's still not clear how those bubbles formed.  In any case, we ironed out these bubbles, and will keep an eye on them to make sure they don't come back.   Hours: 7

Michael ironing around an opening for the aileron pully

Bottom of left wing with leading & trailing edge tapes installed

Top of left wing with leading and trailing edge tapes installed

 

Left Wing, Top Fabric and some Tapes

We made some good progress on the left wing fabric this past week.  On the top side, we glued the fabric down to the tank and installed fabric rivets along the ribs on the top surface.  We installed two doilies on the top that will help protect the area around the tank filler cap, and the exit slot for the aileron control cable.

We applied adhesive for the 2" wide chord-wise tapes on both the top and bottom surfaces, and then installed those tapes.  We also installed two span-wise tapes on the top surface.  We then did some finishing work with irons around the rivets, and also trimmed and glued the fabric at the ends of the wing.  At each end of the wing, the fabric wraps around about 1/2 inch or so.   Next up on the list of things to do will be to install the tapes along the leading and trailing edges of the wing.  Hours: 8.5

Top surface chord-wise tapes installed

Other side of wing, showing tank and filler cap area

Bottom surface, tape at end of wing glued in place