Today was all about working on finishing up the fitting, cutting and construction of the strake bottom skin foam cores.  I also did a lot of assessing and trial fits of both the GIB strake windows and the fuel site gages.

Both the GIB strake windows and fuel site gage positioning are both heavily influenced by a specific GIB passenger body part: the elbows.  Precisely that I modified the position of the BAB baffle to allow for more elbow room into the strakes, then I have to allow for and reserve that aft triangular corner piece of real estate for the GIB’s elbows.  This pushes the aft edge of the window just a hair forward and the fuel site gage as outboard as possible while still being able to see the top of it from standing outside the airplane.

Obviously the passenger most likely won’t be sitting in the aircraft during ground refueling ops, but a key consideration in my configuration is allowing my fuel site gage cameras to get both a good viewing angle of the fuel site gage and also not have the view fully obstructed by the passenger’s elbows.  So again, the more outboard, within reason, the better.

After sitting on my keister in the back seat for a good while, and my initial rough outline of the GIB strake window made, I then took the lower left strake skin foam core outside for a trim.

Here I’m trimming the aft edge to length.

As you can see here.

I then beveled the aft edge at 1.1″ this time.  Of course after I checked it I like the fit 1.0″ better, so I’ll be tweaking it just hair.  Should’ve just followed the plans eh?

I then drew my actual outline (initial) of the GIB strake window.

Here’s another shot.  Note the short cross foam piece that connects the fuselage sidewall to the R23 rib. This diminutive guy will serve a few purposes.  First, it will keep stuff from sliding back onto the window during flight.  I know in the back of Marco’s Long-EZ during Rough River trips we have a lot packed in there, and nothing really to keep stuff secure and from sliding aft over the window.  Nothing horrible or overly annoying, but it would help to have a “catch” if you will.

Next, with the GIB elbow room mod taking the BAB a lot further aft, to help with loads between strake and fuselage I figured I’d add this in for a little added strength. I’ll also do another “mini-baffle” like this at the top about 12″ forward of this one.  On the left that will be even more critical since pax often ingress/egress the back seat over and on the left strake top.

Since I didn’t have tracing paper I used clear plastic to mark out the interior outline of the GIB strake window.

Of course airplane building and feature design is all about trade-offs and compromises.  I would prefer to increase the size of the window going forward a bit, but I want that mini-baffle there in that spot and symmetrical both left and right.  I’ll most likely install an O2 bottle in the baggage area, mounted to the “external” sidewall, so I need most of the fuselage sidewall from aft-to-forward strake opening clear.

Moreover, as was pointed out in a CSA article on these things, the GIB strake windows tend to be a bit heavy.  In the article the builder went with 1/8″ plexiglass simply because it was strong enough and, moreover, it was clearly half the weight as a 1/4″ plexiglass. Well, my strake windows split the difference at 3/16″ thick, and these are not feathers. Total added weight for the size windows I have shown here will be about 1.5 lbs.  Obviously bigger windows means more weight.

I then transferred the viewing area of the window (inner line), which is also the cut line on the bottom, external side of the strake… once it’s finished for paint.  The outer line is the size of the actual “plexiglass” (mine are airline windows) that will then have BID securing them in place up to the inner line.  For more viewing area, as in a bigger window, I didn’t follow the recommended 1″ border as proposed in the CSA article, but rather cut the border down to 0.7″.

I then finished up my GIB strake window template by cutting out the center area.  Again, the interior template line actually denotes the exterior/external cut line (bottom strake surface) where as the outside template line is for inside the baggage compartment.

I then marked the interior template line on the foam.  This gives me the location of the window and an idea of the viewing size.  Plus, by only marking the inner line if later on I get a wild hair I won’t do anything stupid like cut the outer line all the way through, which is not how the install process is supposed to go!

To get the window weights and also have the them ready for install, I used my template to mark the outline on the first of two of my surplus airline windows.

Read to be cut.

I then cut it out using my Skil saw (yup!).

And here’s the second one cut out as well.

With my GIB strake window planning machinations out of the way, I then glassed the baggage area floor of the lower left strake skin foam core.  Since it was later in the evening and the weather is a bit chilly right now (slightly cooler shop), and plus liking the wet out characteristics on a large layup that will get entirely peel plied, I went with MGS vs EZ-Poxy for this layup.  Clearly I plan on doing the remainder of the left strake bottom interior skin with EZ-Poxy.

My last task of the evening was to knock out the fitting, cutting and assembly of the right strake bottom skin foam core.  I have to say I’m very pleased that fitting the bottom skins really isn’t that much more difficult than the top skins, as I had suspected it might be.

A bit later I micro’d the forward and outboard foam triangular pieces to the larger main foam piece to make up the lower right strake skin foam core.

I hen left it to cure overnight. Tomorrow I’ll trim and shape the aft edge and start the 1-ply BID layups on this skin core as well as finish up the left bottom skin foam core.

Today I had planned on starting out on the lower left strake skin foam core and get the pieces micro’d up and curing before pulling the peel ply and cleaning up the top right strake skin core… however, something big changed my work order!

According to the original FedEx tracking # I was due to receive my upholstered seat cores tomorrow (Sunday) but before I made it out to the shop they were delivered.

Here’s the first bag of upholstered bits that greeted me upon opening the box: the headrest pads and armrests.  At first I thought they had gotten the leather colors wrong because the slate gray looked so blue . . . hmmm?

So out in the shop I quickly pulled the peel ply . . .

then razor trimmed the edges and cleaned up the right top strake skin layup.

I wanted to get the right strake top skin core in place to both test fit it and get this shot.  I had to vacuum out the back seat and stuff all the wires back into the D-Deck/GIB headrest.

The headrest pad is temporarily taped in place, which is why it’s a bit off kilter here.  I really like the lighter gray in the seats, and wish I could have gotten a bit more of it into the overall upholstery color scheme, but with them in place I have to say I’m extremely happy with how they came out.

I sat in the back seat for a good half hour and they are really comfortable.  I’ll also reiterate that with the thigh support sump installed, at 5′ 11″ I’m near the upper limit of passenger height for anybody going on more than just a quick local flight.  I’ll also note that when I sat in the back with the extended strake openings that my elbows naturally went into the strake openings…. so the “elbow room mod” is a must for passenger comfort in my opinion.

After test fitting the upholstered back seat cores (I’ll check out the front seat in another day or few, lots of stuff to reorg and clear out up there) I pulled out another sheet of 3/8″ Divinycell PVC foam and started fitting the bottom left strake skin core.

Here we have the bottom left strake skin foam core inboard edge along the fuselage marked and trimmed to fit.  With a flatter vertical surface it’s actually easier to get a tighter fit on the bottom skin core than the top core as the longeron curves a bit on the top.

I then marked and cut the aft outboard triangular piece and the very small inboard front triangular piece and micro’d those to the big foam piece to complete the bottom left skin foam core.  After it cures overnight I’ll take it outside like I did the top skin cores to mark and shape the aft bevel that mates up to the CS spar’s bottom beveled edge.

I’m tentatively calling Chapter 26 – Upholstery complete, given I still need to do a final fit check of the front seat cores. Also, cause I go easy on myself (wink) I planned for 3 days on the lower strake skins since I have the baggage area and GIB strake windows to contend with.

I started out today by pulling the peel ply, trimming the edges and cleaning up the 1-ply BID interior layup on the left strake top skin core.

I then got busy on the right strake top skin foam core.

I measured and marked a line 1.3″ aft of the line I had scribed following the front face of the CS spar.

I then trimmed the aft edge at this new 1.3″ line.

As I did on the left side, I flipped the foam core right side up and marked a 0.3″ reference line from the aft edge.

However, this time I went back and remeasured the top bevel of the CS spar.  I was getting about a 1.2″ wide bevel vs the 1″ I had quickly measured before.  I thought I would try using the entire 1.3″ initially for the bevel on the foam core and see how that went.

Well, that exercise told me two things.  First, about 1″ to 1.1″ works best on the top foam core bevel, so I adjusted it as needed.

The second thing was it was clearly time to knock down the tops of the ribs where they intersected the CS spar so as to ensure the top skin aft bevel mated correctly with the CS spar bevel.  So I spent about 45 minutes trimming and sanding the strake ribs and baffles on both sides to get them ready for both the top skins, and the T-Hat layups.  I don’t have an end-result shot here, but will point that out as I’m working the T-hat layups.

Another issue I had was when I test fitted the left strake top skin core.  The outboard edge (blue arrow) was barely fitting and something was knocking the entire skin core outboard by about 1/8″.  I found the culprit to be the inboard BID flap that is required per plans to come up from the bottom skin and overlap along the top surface of the longeron (yellow arrows).

The problem is that when getting all the glass wetted out along the edge of the underside skin layup, invariably some epoxy goes past that edge.  Thus, along about 2/3rds of this unwetted flap is a hard cured overflow edge that is —not surprisingly— about 1/8″ wide.

The original plan’s method has you glass the top skin then mounting it while the epoxy is tacky, so this flap edge isn’t really an issue. But if you let the skin cure fully then the problem I discovered rears its ugly head.

However, in looking at other builder’s sites I found that Ary Glantz found the solution to this problem: he glassed the underside skin sans flap, then simply laid the glass up (all but the aft 9″) on the LONGERON side first, let it hang down, then mounted the top skin.  Once the skin was in place he simply folded that flap up under the top skin and was done with it (all but the aft 9″ being in the accessible baggage area).  A big thanks to Ary for such a simple solution!

Since my seat cores are back at Oregon Aero getting upholstered, I then threw a seat pad into the back seat and sat back there to assess possible mounting locations for the GIB map light.  If I was going to have it attached inside the strake opening —which I’m not after looking at it— I would have created a hardpoint or embedded a nutplate assembly on the bottom surface of the right strake top foam core.  But I determined that to actually be usable as a map/reading light it needed a bit higher… like shown here on the longeron. Again, my main concern at this point was determining if I needed to do anything to the right strake top foam core in regards to securing the map light.

I then grabbed this shot as I was climbing out of the cockpit,  Note the fuel site gage laying on the left strake top.  I also played around with the positioning of those as well and have an initial idea where I want them… the fairly typically spot they go.

I then cut the big pieces of BID and prepped the peel ply for the right strake top underside layup.

Many hours later this was the end result (think I had a dirty camera lens . . .). This clearly meets my current one-strake-skin-layup-per-day requirement (grin).

With that I left this to cure overnight.

Today was all about the top left skin, although admittedly I had planned to do a whole lot more.  Funny how these builds work out with getting much less done in a day than planned!

I started out by setting up a workbench outside since my shop is a bit crowded at the moment.

As per the Feather Light leading edge strake kit instructions that I have on hand, I marked a line 1.3″ aft of the aft line I had marked on the underside of the left strake skin foam core. The marked line follows the very front face of the CS spar, so that for the matching bevel angle to be made on this foam core aft edge, it must have a reference…. hence, the initial CS spar face line.

I trimmed the aft edge of the left strake top skin foam core at this 1.3″ line, and then flipped the top skin with the top side up.  I then marked a line 0.3″ forward of the aft edge to use as yet another reference line.  The actual aft edge bevel on the CS spar is 1″ from the lower edge moving aft, so this matching edge interface needs to be the same on the foam core. (Ok, so initial cut is 1.3″ but it needs to be just 1″ for actual fit).

I then flipped the foam core back upside down and used this new 0.3″ mark to match the top surface (facing down at this point) to the edge of my workbench.

I then used the Fein saw to get rid of a good bulk of foam and followed it up with my goto 32 grit hard sanding block.  This last step I should have thought out better beforehand as I think 32 grit is a bit too harsh on that thin trailing edge. I had a few spots that broke out, but nothing that just a bit more flox (read: added weight) won’t cure. I’ll be more careful and judicious in my sanding practices on the remaining strake skin foam cores.

I then test-fitted my left strake top foam core.  After a bit of minor sanding in the very inboard corner, it fit a treat.

I then spent the next 4 hours glassing and peel plying the underside of the left strake top foam core.  It’s been a while since I’ve done a larger layup and the sheer amount of epoxy used just to glass one ply of BID to a piece of foam is impressive.

After today’s glassing experience, I’m re-setting/lowering my expectations and goals to finish one of these skin cores a day.  With the shaping, glass and peel ply cutting all occurring pre-layup, it’s quite a production all simply to get a ply of BID onto a flat surface. As I told my buddy Marco, these layups are “simple in theory and a prolonged ass-whooping in reality.”

And I’m sticking to my story… ha!

I actually knocked out the labeling of the Warning Sub-Panel last night after I uploaded my blog post.  Today I clear coated it a number of times as I was working in the shop.

The labels aren’t perfect, even with the clear coat, but since these pics were taken under glaring lights and this sub-panel will be in a more subdued lighting situation under the glare shield, I think they’ll work ok. Admittedly, it is making me rethink the labeling of the instrument panel.

After 2.5 days of cure time for the right strake I removed the cross bar and almost all the securing screws.  This is the first unhindered view of both left & right strake structures installed.

A view from a bit higher perspective to show the strake ribs and baffles.

I then got to work on the left strake top skin foam.  I grabbed a fresh* sheet of 3/8″ foam (*that I bought in 2011) and set it in place on top of the right strake.

I then marked a popsicle stick at 0.6″ and used it to scribe a line down the side of the longeron to capture its curvature on the top skin foam.

Here the line is marked and ready to be cut.

I then cut the outer piece and a small triangular piece at the very front for a grand total of 3 pieces to make up the strake top skin foam.

I then micro’d all the pieces together and left them to cure.

I then repeated the process on the right side.

Here’s the right strake top skin foam sheet ready to be trimmed to fit.

After I fit the 3 pieces on the right side, I again micro’d them all together and left them to cure overnight.

Tomorrow I plan on glassing the underside/interior of the strake top skins and then start cutting and fitting the bottom skins as the top skins cure. If time and cure cycles allow, I’ll prep and get the T-hat rib caps laid up on at least one of the sides.

Admittedly after some long days I am just beat, and got a late start in the shop.  Where I was checking out last night’s layup when I bumped a portable stand kind of hard and sent my micro’d up Warning Annunciator/Emergency Sub-Panel flying.  I decided right then and there to spend a few minutes to sand down the micro and create a smooth surface for painting… and then for subsequent labeling and clear coating.

As you can see, the right side still has cured untouched micro, whereas the left side has been sanded.

Then over the next few hours I ran through the iterations of a couple light coats of primer followed by a couple coats of matte black paint.  The micro’d/sanded/painted tabs provide a smooth surface to affix labeling to… to then clear coat over for a nice labeled sub panel.

After my initial round of sanding and painting the sub-panel above, I then spent a good bit of time pulling all the peel ply, razor trimming and cleaning up all the right strake layups from last night.

As I did on the left side, I also used the “Fein” saw to trim down the back vertical edge of the GIB strake fuselage opening.  I then sanded it down and glassed it with 2 plies of BID. I then peel plied the layup.

I then did a repair layup on the left side OD rib.  I noticed this when I was horking on the left side leading edge that I cause a slight crack at the top side of the OD rib attach to the CS spar.  Since I had to reshape the nose, apparently I didn’t get it exactly right and with enough pressure on the front of the OD rib it caused a slight separate (about 1/16″ or 0.060″) at the top aft edge of the OD rib.

I removed the glass on the top half first, cleaned up and sanded the remaining surfaces before laying a couple plies of glass back in … with some more flox of course.

Here’s the reglassed outboard side of the OD rib as well.

Kind of crazy how long a few layups took start to finish, but with these in the bag I called it an earlier night.

Tonight was one of those huge milestones for this airplane build: I finished installing all the ribs and baffles for the right side strake, and thus the entire plane.  Good thing too because those layups spending hours and hours on your knees, trying to jam BID tapes, flox/micro fillets and peel ply back into very tight corners is a backbreaking workout and a half!

Here’s the right strake with the very front duct tape pulled and the R23 rib installed.  Since so much of this strake structure is cantilevered out from the CS spar, I’m giving the right strake —as I did the left— 3 entire days to cure, as I leave all the leading edge to ribs/sidewall screws, duct tape and wood support clamps in place.

Here’s a higher angle shot of the R23 rib installed into the right strake.  I have to say that I’m very pleased that the elevation of the right strake at the R23-leading edge intersection is within 0.050″ of the left strake…. not bad!

And outboard/inboard shots of the leading edge side of the R23 rib install.

And outboard/inboard shots of the aft CS spar side of the R23 rib install.

A side shot of the right strake R23 install.

Here we have the DB baffle and extended/modified BAB baffle installed.

A couple aft forward shots of the DB baffle and extended/modified BAB baffle install.

And a requisite shot of the extended/modified BAB baffle through the GIB sidewall strake opening.

Finally, a shot of the installed R23 rib peeking through the front seat strake opening.

I still have a myriad of strake-related tasks to knock out as I move on to the next major structural piece of the strakes: the top and bottom skins.