I started out today by spending over 6 hours updating various parts of this website.  I cleaned up the electrical system main page by adding subpages, and I added a subpage to the Chapter 21 page for the GIB thigh support fuel sumps.

I then finally made it into the shop very late in the afternoon to start in on the fuel sump top exterior.  My goal was to get the sump top exterior glassed today, which I was able to do.

I started by spending a couple of hours working on the sump tanks access ports’ holes. My theory on the glass pulling away from the foam was right for the most part, which distorted the shape I had created for the way the metal nutplate rings would lay in the depression ring around the underside of each hole.  Being an ‘ol Bomb Disposal Tech, I simply improvised, adapted and overcame by taking the topside hole perimeters down to glass.  The glass ring around each hole isn’t optimum for what I want to do, but it’s definitely workable. Most notably, what it will probably mean is that each top cover plate will have to be curved slightly to match the (now) more curved shape of the just glassed rings.

Once I removed the foam around each access hole and took the hole perimeter down to glass, I then found the optimum alignment between top and bottom plates, then drilled the 7 screw mounting holes in the ring around each access hole.

I then sanded a transition in the foam around each hole to the surrounding foam surface, and also hit the raised “square” edge lines that where an unwanted byproduct of curving the foam with heat and using a weighted board to make the curve.  I should note that I had already sanded both the right and left sides of the top to get the edges aligned with their respective sump walls, exterior/outboard sides. Once I cleaned up the top foam surface of the sump top, I then vacuumed it in prep for glass.

As for the glass schedule for the exterior of the fuel sump top, it was slightly different than how the rest of the sump was glassed.

Obviously I want this sump to be more impact resistant than if I had just used BID alone. So, for both strength and impact resistance, and to add another ply for fuel resistance, I made the first ply on the interior sump walls Kevlar.  However, since the top will see its fair share of things dropped on it, getting stepped on, pointy things trying to pierce it, etc. I went ahead and put the Kevlar on the exterior side, covered by a ply of BID.  I did add another 6″ wide strip of BID across the front of the top cover for strength, especially for the glass-to-glass access holes’ rings.  Then, immediately around each sump tank access hole, I added another ply of BID.

Finally, before I laid up the final top ply of BID, I added a small strip of Kevlar in the center in between the access holes (where the bridge of the “nose” is on my very humanoid looking layup . . . can you see the eyes?!) which is essentially where the GIB will step every time when ingressing & egressing the airplane.

I’ll let this layup cure to around 75-80% (i.e. in the morning) before placing it on the sump assembly in the fuselage, where it will get weighed down on the edges (again) and cooked to perfection with heat lamps!

Today I started out by cleaning up the edges of all the metal pieces I cut yesterday.  After removing the plastic covering on each side of all the metal pieces, I realized that the plastic itself was hiding a bit of a sharp ridge all around the edges of the cut aluminum, so I took a fine file and smoothed the edges down.

I then drilled out the rivet holes for each nutplate assembly on the sump tank access ports’ internal rings.  After I drilled the pair of rivet holes for each nutplate, I then drilled a countersink for each hole to allow the countersunk rivets to be installed flush.

I then Alodined the sump tank access ports’ internal rings and hung them up to dry.

With the sump access ports’ internal rings Alodined & drying, I then cut all the BID required for glassing the underside of the sump top.  I prepped the foam surface by applying wet micro-slurry to it.

I then glassed up 1 ply of BID across the front edge that also covered the sump access port holes.  Then, each hole got a ply of BID that just covered the hole, making 2 plies of BID around the edge of each hole.  After that, I laid up a ply of BID that covered the entire bottom side of the sump top, obviously making 3 plies of BID around the edge of the access holes.

I used 3 plies around the holes because I was originally planning on going glass-to-glass between the top and underside of the sump top around the lip of each access hole.  I decided that I most likely wouldn’t go in that direction now, but I wanted to keep that option open and I had already cut the BID for this layup, so I went ahead and added the smaller ply around each hole . . . which is the only difference between going the glass-to-glass route or not.

I then peel plied all the edges, around each access hole, and a fairly wide strip down the center from front to back.

As the layup on the sump top foam piece underside cured, I then riveted 7 covered nutplates to each sump tank access port internal ring.

I then left the layup to cure for a few hours and went to dinner with a buddy of mine.

Since E-Z Poxy with EZ84 hardener takes around 8 hours to cure, I had already planned on letting it cure about half-way so that it was nice and tacky, almost greening, but definitely setting up before putting it in place on the sump tank in what will be very close to its installed position.  Of course, before I set the glassed & curing sump top in place I applied clear packing tape to the tops of all the vertical sump components, and the aft dam area.

I then piled a bunch of weights on top of the glassed sump foam top to press it firmly in place along all the contact points.

After a few minor adjustments of the weights, I then mounted the 2 heat lamps and fired them up.  I then covered the area with an insulated foam panel.

Tomorrow I plan on glassing the top side of the sump top, but I won’t glass it in place onto the sump since I need to flox the sump tank access ports’ internal rings in place before the top goes on for good.

Today I started off by sanding the internal foam edges around each sump tank access port hole.  Since the sump top is angled and slopes down almost immediately from the front sump wall, I want to get the sump access port covers configured so that they are as level & parallel with the aircraft’s waterline (0°) as possible.  To do this means that the foam around each opening is actually shaped so that on the top side (remember, I was working on the bottom side of the sump top foam piece) the foam is low on the forward side of each opening and as high as possible in the back.

To prep the inside foam for glass, I simply reversed what will be seen on the top with the front side getting a slight depression –in preparation for the 0.040″ thick nutplate ring– and the aft side getting a much deeper depression, when inverted, meaning that it will place the nutplate ring nose side low and tail side high.  Exactly what needs to happen to get the access port cover as level as possible.  I spent well over 1.5 hours sanding & shaping the foam around each opening (and my aching shoulder can confirm that it was that long!).

Since I’m meeting friends early this evening for dinner, I wanted to ensure I got all the noisy stuff for today’s build out of the way as early as possible.  I loaded up a new bit on my Saber saw and cut out the 2 nutplate rings out of 0.040″ 2024 aluminum.  I then spent a good 5-10 minutes on each one cleaning up the inner & outer edges with a file.  Of course cutting them with a Saber saw meant they didn’t come out perfect, but they certainly meet my requirements and will do the job fine.

I then matched each ring up with a port cover plate as best they aligned and then taped them together with clear packing tape.

I then used my paper template and marked the 7 screw holes on each ring.  I then drilled out the screw holes to attain a spot-on alignment between each nutplate ring and cover. To ensure I didn’t get the cover plates or sides mixed up, I used a scribe to place a small “A” on one set, both cover and ring, and a “B” on the other.

I then pulled the protective film off all the aluminum, set up a screw to show the alignment between cover & ring, and then set a number of the covered nutplates in their positions to provide a general idea of how these pieces work & go together.

Tomorrow I’ll Alodine these aluminum pieces and glass the internal side of the sump top cover.  I’ll then rivet all the nutplates to the sump access port cover rings.  Since E-Z Poxy needs a good cure, I won’t really get to glassing the sump top in place until either Sunday night or Monday.

Well, I have to admit that when I started off this morning by using 5-min glue to mount the fuel vapor sensor module’s clickbonds in place, I realized I have may have been a bit too thick with the praise for MGS over E-Z Poxy when it comes to mounting clickbonds, since I do quite often use 5-min glue to initially hold them in place.  However, I will still state that I have not had an issue with either 5-min glue or MGS when it comes to clickbonds.

Moving on.  I prepped the bottom of the fuel vapor sensor module with clear packing tape, then put some dabs of 5-min glue on each prepped clickbond and set it in place.

A bit later I laid up 2 plies of BID over these clickbonds and then peel plied the layup.

Today I also finished drilling & countersinking the rivet holes for the nutplates that will eventually get mounted onto the armrest (etc.) mounting brackets.

Here’s a shot of the drilled and countersunk rivet holes in the mounting brackets.

I then Alodined the armrest mounting brackets and the FT-60 Red Cube fuel flow sensor mounting bracket.

I then riveted the 90 deg. corner -4 nutplates in place on the FT-60 Red Cube fuel flow sensor mounting bracket.

Here’s a shot of the bottom side of the bracket (my Alodine is a bit old, and unlike a fine wine it doesn’t get better with age… maybe that explains some of the splotchiness on my bracket… not sure…)

And here is the  FT-60 Red Cube fuel flow sensor mounting bracket after I floxed ‘er up and bolted ‘er in!

I then got to work on the Roll Trim mounting pad.  I had ordered K1000-06 nutplates for the 6-32 screws that will be used to mount the RAC servo to the fuselage sidewall.  Well, I had a “Doh!” moment when I realized that since the RAC servo has corner mounting holes, I should have ordered 90° corner nutplates.  Oh well, since the Roll Servo is fairly light and in normal ops not an overly used device, I made a command decision that one rivet tab would do to hold each nutplate in place on its respective G10 Garolate nutplate base.

[Note: Normally this servo would get mounted straight to the sidewall, but since I had to kick in my control tubes about 3/4″ inboard to allow for the CG controls, I am simply “extending” the fuselage sidewall inboard 3/4″ with this foam base]

Once I got all the nutplates riveted to their 1/16″ G10 base, I mounted them to the RAC servo and figured out their exact location in the foam.  I then notched the foam at each corner and embedded each nutplate assembly.

I then taped up the bottom of the RAC servo to use it as a guide, and then mounted the nutplate assemblies back onto the servo.  I then micro’d up the bottom of each nutplate assembly and the corner notches in the foam.  I set the nutplates (with servo) in place, and once satisfied that they were all in the right position, weighed down the servo to press the nutplates into their respective notched corners (I failed to get a pic prior to this of having shaped the edges of the foam to allow for glass transition to the fuselage sidewall).

Later, after it all cured, I filled each nutplate with plastic/saran wrap to keep the micro out of the nutplate threads.

Later still, I prepped the foam roll trim servo base with micro and micro’d it to the right fuselage sidewall just aft of the pilot’s seat.  I then laid up 3 plies of BID over the foam base and then peel plied the edges with 2″ peel ply tapes.  I double checked the elevation a few times using the RAC servo with the spring push/pull assembly attached.  With only a few minor tasks left, like drilling the screw holes and pulling the protective plastic wrap out, I’m calling Chapter 17 – Pitch & Roll Trim Systems, complete!

Tonight I floxed in 3 mounting tabs that were screwed to the GIB left armrest.  These are 3 of 4 tabs that are located primarily on the aft side of the armrest.  I’m planning on building a small framed mounting bracket that will be used to also house the GIB headset jacks and PTT button on the front side of the left armrest, which will have a nutplate attached to it and be the 4th mounting tab.

In addition to the left side armrest, I also added another mounting bracket to the GIB right armrest by floxing in place a tab on the aft side of the armrest where it meets up with the seat back.

Tomorrow I really do plan on working on the fuel sump top, but will be going out to eat with some friends so it won’t be a completely full work day.

I started out today wanting to get the FT-60 Red Cube fuel flow sensor mounting bracket finished so that I could Alodine it with the armrest mounting brackets that I planned to prep as well.  Well, I went as far as I could before having to get on the road to head up towards the Dulles area to help out a friend.

I did get the FT-60 bracket configured with the mounting bolts drilled and the corner nutplates’ rivet holes drilled out as well.

I countersunk the rivet holes in prep for using flush rivets.

Thankfully, after the click bond disbonding issue, I was able to get the bolt holes aligned correctly, since the Red Cub sits on its bracket at a slight angle left-right to align properly with the fuel feed tube.  I added the nutplates in the pic so you can get a sense of how it all goes together.

Also, after pondering it for the last day or two I decided that with all the fuel lines, fittings & components in the back seat area –and the entire cockpit actually– that the fuel vapor sensor that I bought while I was in Qatar was going back into the lineup.  I just think that it’s the prudent thing to do to have the earliest possible warning of any fuel leak, at the vapor level before it gets any bigger/worse.  I decided on an out-of-the-way spot for the sensor element and will mount it there (it’s just mocked up here) with 2 click bonds using?! . . . yep, MGS!

I know I stated in my video that the sump top was the next item to be worked, and I have been (slowly) working on curving the top cover of the fuel sump by heating it up.  I have never undertaken the curving of foam by heating it up, as the plans references a few times for curved foam parts.  The feedback that I’ve seen on this method has not been good, and most people generally cut relief grooves and curve the foam that way.  I wanted to try it simply out of curiosity.  It does work, but there is some inherent problematic issues in heating it up to curve it.

First, I started off trying to simply use the fuel sump as the form and set the lid foam on top of it.  I then weighed it down and heated it up in place there.  I thought there might be some issue with some spring back after I removed the foam once it cooled, and I was right.  With that knowledge in hand, as well as some nice scrapes on my fuselage floor from heavy weights leaping off the tricky curved sump surface, I decided to shape the foam off of the actual sump.

Next, to get an even curve, I used a 1×4 board base as I weighed it down with weights with the top set upside down against a 4×4.  Well, the end result was angled curves with “corners” somewhat like you’d get with a hex shape.

No big deal, but it is something I’ll have to contend with.  I’ll keep working the top sump cover as I finish up these smaller sideline tasks for the time being.

Finally, I spent a good couple of hours working on my last batch (hopefully!) of mounting tabs for the GIB left armrest, as well as backfilling some inventory that I stole from the front & aft right side armrests.  Over the next day or so I do intend on getting the GIB left armrest mounted, as well as getting 2-3 more tabs mounted on the right side as well.  I did run out of time finishing these up to get them Alodined before installing them, so I will work to get this batch knocked out tomorrow.

After a not so productive weekend as far as the airplane build is concerned, I’m hoping for a very productive week!

Ok, obviously I have no hard facts or empirical evidence here, but after some cleanups and just general workings with E-Z Poxy, I have to say –or rather my gut says– that E-Z Poxy is just not as strong as MGS.

Case in point.  Yes, this may just be an isolated, one-off chance incident, but in the myriad of click bonds that I have used in my build thus far, I have always given the threads a good wipe down after I layup the glass over top of them, and then after it cures I use a thin standard nut to clean up any small film of epoxy from the threads.  I start the thread on, and analogous to tapping threads, I tighten it till it gets firm, give it a little extra push, then back off.

I’ve never had an issue cleaning the threads this way until I hit my first click bond that I used some leftover E-Z Poxy flox to mount the 3 click bonds for the Red Cube mounting bracket.  As soon as I got to that first little oomph, I could tell the click bond snapped free of its bonded base.  Of course, then I didn’t have a good way to get the nut off since the base was spinning feely!  After messing around with it for a bit, I simply used my Dremel cutoff tool and ridded myself of the useless post & nut.  For the next 2 click bonds I was of course much more cautious, gentle and moved much slower, grumbling and NOT happy with E-Z Poxy the entire time!

Coincidence?!  Maybe so, but this builder will never find out because I’ll simply stick to MGS from here on out.  Thus, my cool 3 click bond posts for the Red Cube mounting bracket are now simply 2 posts, and I’ll flox on the mounting bracket for extra measure when it goes on.  Since these sit on the fuselage layup for the main landing gear mounting brackets, I’m not messing around with digging that click bond out or redoing it…. I just won’t chance doing more damage to some very critical fiberglass.  I’ll just chalk it up to being in the aptly named “Hell Hole” and move on . . . with lesson learned in hand.

With the MGS epoxy that I used for laying up the BID over the fuel pulsation damper Adel clamp and red cube mounting bracket click bonds, I also had whipped up some flox to mount the slightly undersized threaded rod of the lower roll trim spring assembly into the RAC servo’s clevis.  I forgot to get a pic yesterday, but here it is today nice and cured.

I had planned to do much more but messing around with the kaput click bond burned up the time I had since I had to take off mid afternoon to see some friends.  Tomorrow will be essentially a non-build day so I’ll get back to it Monday, although Monday late afternoon I’ll be helping a friend with some stuff . . . so also not a full build day!