After preparing the latch pockets, now the latch pin guides.  These are originally intended to secure the Van’s weatherstripping. I want to add them as a framework for some resin around the pin blocks.  The idea here is fully enclose the pin blocks in order to provide a smooth, sealed surface for the McMaster seals.  Yes – the pin blocks will be permanently encased in the door, but there are ways to install or remove the pins without dismounting the pin blocks. (more on that topic will appear in later posts)

First steps are layout the pin guides on a sheet of .040″ aluminum.  The designated 6.8degree angle supposedly compensates for the angled door frames. A protractor is used to get the angle close (only has degree increments).

Stiff construction paper prototypes were cut prior to making any metal parts.  I wanted to check the effect of the angles on the corners.  Close enough for some hand shaping to be effective.

The roughed out pin guides are then inserted in Tal’s sheet metal bender and formed per plan instructions.

Here are the pin guides prior to fitting on the doors. Actual fitting required a bit of material removal. In retrospect I would first fit the pin guide hole from a slightly larger blank template, then shape down the attachment tabs to fit to the door geometry.

Here are the raw and final fits on the passenger door aft guide.  Getting the pin hole aligned properly took time with hand filing.  The final gaps are good.

Here is a passenger door forward guide. Much easier since this is a straight piece.  Now everything is ready for alodine/prime and covering the pin block with resin.

The slow process of applying filler and sanding on the doors, frames and canopy finally has an end in sight. Much of the time was preparing the door frame J-channel for accepting the McMaster-Carr weatherstrip molding.  My intention was leave as much of the original canopy material in place as possible, just relieve enough for a good fit between the final lip and the door inner shell. In most cases this was sufficient, but on the lower door halves the default gap was wider than could be bridged by the weatherstrip.  Here I opted to apply fiberglass/resin to build up the outer edges, then sand smooth and fit for a much better gap.

These photos show the lower left and right corners of the passenger door.  This was the hardest area to build up.  The default J-channel was very irregular, varied in thickness and sanding in the corners was difficult.

After getting the doors to an intermediate fit, off came the doors and hinges.  The intention is to send out the hinges for chrome.  However, the steel finish as provided from Van’s is pitted or marred with milling marks.  The portions which will be most visible after installation were hand sanded and polished. Hopefully this preparation step will lead to a better final look in chrome.

Another set of fabricated items for the doors are hinge spacers for the Bansbach gas-struts, and bracket locating bars made from 3/8″ plywood.  These bars will be used to properly set the distance from the AirWard strut brackets to the hinges on the inner door panel.

LATCH MECHANISMS

The exterior door handles provided by Van’s extend quite far from the door surface.  After long deliberation I opted for the AeroSport low-profile handles.  This requires modification of the latch pockets, but now is the perfect time as the doors are not finished anyway.

This photo shows a thin metal striker plate will be fabricated to accept the modified Delrin block to hold the standard latch gear and accommodates an integrated lock mechanism. This requires boring out a larger hole for the handle lever and a pass-through for the lock body.

The right photo shows the passenger door being modified for the larger lever body and lock hole.

After the modification, the fiberglass around the lock is quit thin.  Now I see why a plate of reinforcing steel is needed.

The lock does fit well, though maybe a lock with a shorter body would be better.  Why – the Phillips screw holding the locking lever extends above the surface of the door interior.  This would make fabricating a vanity or cover plate difficult.

AILERON PUSHRODS

My first attempts at making the aileron pushrods did not turn out very well.  So I reordered the parts and tried again…

This picture of the initial rods show how the rivet hole is chowdered badly from the drill press.  The rod was not secured properly and moved drastically during the process. My bad.  The rod was being held in a drill vise with the end sticking out, no support provided on the outer end to take the pressure and keep the rod from bending.

At least two lessons were learned from the previous exercise:  measure twice…  and make sure the part is properly secured when drilling.  In this photo shows measuring the 48″ rod to ensure there is sufficient room at the end to fit into a precision V-block on both sides of the drill location.

After spot drilling (lesson 3 for small diameter rods, keeps the drill from wandering on initial contact) the separate inner holes are drilled.  Note the V-blocks on each side.  The rod was then cut in half and the two pushrods were adjusted by hand filing to 21 – 11/32″ length.

The drill results are very good.  The insides need to be primed, then all the through rivets will be inserted.  The right photo shows a end of each rod with one rivet.  Nice tight fit and no wiggle in the threaded ends.

Sanding and fitting door to the canopy have been my main activities over the past few weeks. The work has been tedious, but I prefer taking off smaller increments to slowly get the shape down to cabin contours than accidentally removing too much with a power tool.

First up was finish bonding the passenger side door together around the windows and exterior edges.  That done, next mount the rough door on the canopy opening.  The right picture shows marking a rough  cutout line using a special jig tool made by Tal.  Worked great!

Here the custom tool with a very fine point Sharpie marks the upper door edges. The Sharpie line roughly equals the scribe line in the fiberglass outer shell, but differs enough to require carefully measuring all around.  As usual, the fiberglass mould used for the canopy is just an approximation, nothing precise at all.

Left picture is a rough trim on the upper door near the hinge.  Notice the single alignment tab still the outer edge. The right photo shows a later fit after many, many hours of hand sanding.  The last bit of shaping used a folded sheet of sandpaper moved back and forth sandwiched between the door and the canopy frame.  Makes for a nice fit.

Here is a closeup of the door against the cabin center column.  The next step was tape the roughed in door into position, get ready to install hinges.

A two foot straightedge is used to mark the centerlines of the hinges.  If the hinges are not aligned just right, they will bind when the door is opened.

Okay. Drill the canopy hinge first, and install four temporary #10 screws.

Open the door for the first time and check the fit.  The edge distances are uniform and the hinge action seems smooth although only two screws hold the door in place.

The remaining door hinge holes are then drilled and screwed.  The next major focus of the door build will be contour the canopy gutter edges to the proper geometry for weatherstrip moulding.

Some touch up of small edge gaps from the previous bonding process remain before moving on.

Over the past few weeks, many distractions for home improvements have gotten in the way of progress on the plane.  However, a recent visit from Rich has helped put wind back in the sails.  My approach was to finish as much work on the latches, gear boxes, pin blocks and other accessories prior to bonding the inner and outer shells together.  Made for much easier access to some tight areas.

Here the Delrin pin blocks from PlaneAround are being shaped with a vixen file to match the corresponding door pockets.

Next action is bond on fiberglass reinforcement squares from the PlaneAround kit around the center gear box.  A cover plate was fabricated to cover the cam shaft slot opening on the inner door panel.  This is not required for structural reasons, but should add a finished look.

The default Van’s pins are bent, measured and cut in preparation for adding stainless steel and machined PlaneAround pin tips.

The pins are cut to approximate length, but must be hand filed for the machined pin face to be oriented correctly.  When done right, the pins should pull the door down and in when engaged.  The pin is tapped for a 3/8-24 bolt which is tapered slightly for easy insertion.

Rich confirmed proper geometries and alignment of the latch parts, then began preparing to apply foam for sound dampening.

The last step before bonding is shave the foam flush with the inner surface.  The shells edges were sanded and test fit to ensure no excess foam interfered with smooth surface contact.

BONDING PROCESS (over a few days duration) ================

Over at the rented shop, the right side is covered with plastic to prevent extra adhesive from squeezing out the edges onto the canopy.  Then West System epoxy is mixed together.  A batch of ‘neat’ (no fillers) with three pumps resin and three pumps hardener was prepared to wet both shell surfaces.

Here the elbow pocket is covered wet before application of a 5 x 9 inch piece of Permabond (triple layer fiberglass mat).  The mat was thoroughly soaked in neat adhesive.

This photo shows wetting the cranial cavity on the inner shell.  This area was treated with the same Permabond as for the elbow pocket. After this operation, I had an issue with the bonding material used for the right door outer edges (more on that later)…

When done properly bonding the outer edge used three separate batches of three pumps each of resin/adhesive first mixed together, then stiffened with six spoonfuls of West 406 (colloidal silica).  The consistency turned out similar to peanut butter.  The final adhesive mixture was spread about 1/16″ evenly on each surface before mating together.

Clecoes hold the lower section to the fuselage through witness holes.  Clamps have been applied to the sides along the door channels.  Sandbags about 25 pounds each and other extra weights hold the top section in place.

Rich had the good idea of using kraft sticks to distribute the clamping pressure along the door edges.  A firm, uniform clamping force is desired.  Too much pressure causes the adhesive to be forcefully ejected from the bonding location – effectively ‘starving’ the joint and causing a weaker bond.

Here is photo from a different day of the left door clamped onto the canopy to cure.  The recommendation is allow 24 to 48 hours to harden before removing.  This lets the door permanently shape to the contour of the canopy.

The bonded door shells are very tight, no fear of delamination here! Now begins the process of trimming the shells to final dimensions.  First the window frames, then the door edges to match the frame openings.

Confession time:  On the right door I mistakenly used sealant instead of fiberglass adhesive on the outer edges. Fortunately I was able to completely remove the sealant before proper application of the epoxy adhesive.  Overall the final outcome for both doors was very good and structural integrity is preserved.

While waiting for replacement parts for the flap control rods, I began working on the cabin doors over the holidays.  My intention is prep, align, fit, and sand as many of the door latch parts as possible before bonding the two shells together.  This should make the incorporation of a PlaneAround NEW180 cam door system much easier.  This approach does require a sequence deviation from the original Van’s plans.

First step is scribe lines on the inside of the window frames.  The 3/4″ line will eventually become the edge behind the plexiglass windows.  The other lines are for rough removal and setting temporary clecoes.  The right photo show a few clecoes already installed along the bottom edge.  I started here because the original witness holes are here and should provide excellent alignment between the shells.

Next is fasten upright on the workbench and clamp inside the window frames.  This should press the shells together and progressively flatten moving upwards for clecoe holes.  Drill, clecoe, reset clamps, repeat until the inner frame is solidly fastened together.

Clecoes are now installed at the windows.  The entire door frames is then rough fit to the fuselage via the outer witness holes.

Gaps to the fuselage are acceptable at this stage.  They should become tighter as the door edges are trimmed.

A 3/32″ hole finder is used to align open rivet locations in the fuselage with edges of the door shells. Holes are drilled, then clecoes inserted. Without the hole finder, this process would be nearly impossible to perform accurately via scribe lines!

The rough fit process is completed with good results.

LATCH MECHANISMS

Now the doors are clecoed together, work on the original Van’s latch mechanism can begin.

As usual, the parts are laid out before processing. Following the original plans, the C-RACK 10 was cut to Van’s specifications only to find the lengths need to be different for the PlaneAround kit.  Oh well, another opportunity to order replacement parts.

In the meantime, the latches are positioned in the middle of the corresponding door pocket both vertically and horizontally. Here are the final drill holes shown inside and out.

CAM GEARS / BACKERS

Having the door shells apart greatly facilitates working on the cam gear installation. One item of concern is the lack of reinforcement around the gear block.  Access to the inside surfaces allows for creating a custom solution.

This plate made from spare .040″ aluminum sheet is match drilled for the gear block, plus will have #6 nutplates installed for a vanity cover.  These alterations should provide increased strength together with the fiberglass reinforcement blocks from PlaneAround.

This backer is for the gas strut attachment at the door (a standard Van’s feature).

PIN BLOCKS

Now for custom fitting the Delrin pin blocks to the door frame. The white block from Van’s is shaped to fit exactly in the corresponding pocket, then used to match drill attachment holes through to the outside shell.  The black PlaneAround piece has an extended pin guide and will also be custom shaped for the pocket.  The existing holes will provide a template for the new pin blocks.