Chapter 21 – Internal GIB Thigh Support Fuel Sump Tanks
[NOTE: These internal sump tanks are NOT per plans and are only shown here in a continuation of the documenting of my Long-EZ build. This aircraft is not flying yet, and these sump tanks, along with my fuel system, will be subject to rigorous testing prior to flight. Any builder that copies any part of this design does so under their own volition and accepts all risks associated with doing so.]
16 May 2017 — Today turned out to be an all day planning & coordinating endeavor.
I’ve been having a back & forth email discussion with my buddy Dave Berenholtz on, well, just about everything involved in the build, but today specifically was on the sump tanks and the fuel system. I haven’t really communicated my fuel system since I have been researching, studying, and planning it for literally 4-5 years now.
Thus, today was the day to polish off the particulars on my fuel system and get it finalized so I can implement it. To understand my fuel system planning, I will be throwing out some big names in the canard world…. not to name drop, but to show the pedigree (not mine) and experience of those involved in this discussion.
It started a number of years ago as I was talking to Marco on the phone and sent him a link to Wayne Blackler’s Long-EZ to make a point as to what I was on about. After a few minutes he simply declared over the phone: “He has no external sumps.” He noted something I had failed to notice, and we pondered over that a bit. I bit later I discussed with Wayne his “no-management” fuel system, as I did with Ken Miller, Bill James, and Vance Atkinson, among others. So, although I started out ready to install the plans version fuel system, I made a distinct departure from that plan and decided on a GIB thigh-mounted central sump with no fuel selector valve system. I was going no-management all the way Baby!
Well, my planning was geared towards the no-management fuel system for years when last year before RR I made one final search online before installing my EFII fuel pump right below the CS spar…. and I mean it was going literally on the bottom surface of the CS spar, centerline. I have to say I had a nagging feeling about putting all that weight back there (it’s 2.5 lbs), and when I saw a pic of Joe Carragio and few others who had mounted there fuel pump under the pilot thigh support, it got the gears in my brain turning. Hmmm…
I did a quick mockup of the fuel pump up in the pilot thigh support area and realized it would fit perfectly. Hmmm…. Ok, well a big reason that I was going with the no fuel management system was the integral GIB thigh support sump, meaning: no external sumps. Why is that important to me? Simple. I have the Berkut-style armpit engine cooling intakes on my cowlings. These sit literally inches behind the plan’s external fuel sumps. This means not only accepting more drag in general, but bringing disrupted, disturbed, burbling air into my engine for cooling. Not optimal. The no management thing, well, that would be nice. Of course, that came with a decent, unique risk all its own. But added drag and disrupted engine cooling air! Well, I was not willing to accept that when I could simply move the fuel from an inch away from the GIB to an inch away from the GIB (IMO!)
Fast foreward. After pondering it for a number of months, looking at the pros & cons, I decided to do what “we” in Washington, D.C. are best at: COMPROMISE! I decided to go GIB thigh support sumps (yes, plural) by simply not making the mouse holes that would normally be made in the center rib of a single tank sump. I then would use the Andair fuel valve I bought many moons ago –since I was adding fuel weight going forward anyway. Moreover, since I needed a fuel line going to the pump, and a return coming back, what was the complexity or weight of one more?
The bottom line is I will be going with a hybrid fuel system. No external sumps with internal fuel sumps under the GIB thigh support (yes, I know the arguments of “bringing fuel into the cockpit” . . . and clearly I’ve weighed all my pros & cons, and risks & benefits). I will however keep the separate tank concept by running the fuel through the Andair L-R-OFF fuel selector valve.
Today I confirmed installation requirements with EFII for my fuel boost pump and Precision Airmotive for my Silver Hawk EX fuel injection system. After getting questions answered regarding size and location of filters, and fuel pressure sensor connection info, I finalized –after 7 years– my fuel system!
Now, to throw yet another wench in the works, I’m strongly considering knocking out my internal fuel sump in the back seat, which would then allow me to ACTUALLY run my fuel lines for the left & right sump feeds to the fuel valve. In addition, that would clearly give me the info on spacing requirements I need for fuel lines, wiring, etc. going down the right sidewall. This would also give me all the real world clearance specs I need for the pilot thigh support ribs and configuration, under armrest configuration for the right side, etc.
I will sleep on it, but I am strongly leaning in that direction as my next move.
Also today, besides updating my fuel system diagram (last updated June 2014) and my firewall components & wiring placement & configuration diagram (last updated Feb 2014), I also updated the fuel system wiring diagram and the engine information/management system wiring diagram. That may not seem like much, but the phone calls and digging into the manuals and websites to confirm, verify and update components, do analysis on part selection, prices, check inventory, etc. . . . well, that all consumed about 6 straight hours.
I then spent a good hour sitting in the back seat, marking up my thigh support requirements, and then trying to guesstimate how to translate that over for the passengers I’ll be carrying. As a comparison, the thigh support mod spelled out in CP 28 has the front wall at 37″ forward of the firewall, 4.5″ high, and then tapering back 6″. Before climbing into the back seat I looked at Dave B’s sump tank, which is a little too robust for me (in all fairness, he called that), and Bill James’, all online of course. I then looked at the Berkut GIB thigh support sump plans, reread emails from the whole gang I mentioned above, and then after a few machinations dialed mine in at 35.5″ forward of the firewall, with a height of 6.2″ and tapering back around 10″.
17 May 2017 — Today I got to work mocking up the GIB thigh support sump tank assembly, which will include separate left and right sump tanks.
I used cardboard to mock up the forward wall and center rib. Obviously, this isn’t exact, but my main goal here was to get a general idea of size and dimensions . . .
and check out two different sizes for the Holley Hydramat fuel pickup mats that I decided to purchase for the sump tanks (thanks to my buddy down in Oz, Dave Berenholtz…. I think he owns stock in Holley!).
Why the Hydramats? Well, the really cool feature for these mats is that as long as any part of it is touched by fuel, it will get it to the fuel pump. But for me the overriding selling point is the fact that it also pulls double duty as a 15 micron filter. With Nick Ugolini and other builders warning me of installing filters to catch all the bad fiberglass stuff that will inevitably rear its ugly head, I want that assurance that at the last main point that is composite: the sumps (with of course the composite fuel tanks preceding the sumps), that good filtration for the nasty bits before/as the fuel departs the sumps is occurring.
Since I have both a left and right sump tank, I of course require 2 Holley Hydramats. Now, these things will work fine bent at an angle, say 90°, so I test fitted the available 3″ x 8″ and 3″ x 15″ versions by using paper templates. These things aren’t overly cheap, and the latter version is only $10 more, so for almost double the surface I was really trying to make it work. But, with the internal configuration of my sump, it just didn’t fit well and would be wasted surface area. Thus, I went with what fit well and pulled the trigger on a pair of 3×8 mats.
Here’s another shot of the 2 sizes in the separate sump tanks.
Today I also did over an hour’s research on fuel system related topics. I then went down to the shop and decided to knock out all the 1/4″ 2024 aluminum hard points for both the pair of sump tank fuel drain valves and –while I was at it– the pair of main fuel tank fuel drain valves that exit the front of the strakes.
I marked up my 4″ wide (convenient eh?!) piece of 2024 into 1″ squares. Then, knowing my Sharpie lines would be gone in 3 seconds after I started, I scribed the lines. I then center punched the crosshair for each hole for a nice starting point for my drilling.
I then drilled subsequently larger holes . . .
Until I finished drilling the holes out for the final diameter required for a 1/8″ NPT Tap: 11/32″.
I then started tapping all the holes in old skool fashion with the tap and a crescent wrench — and of course some cutting fluid.
Yes, I really wish I had a nice tap handle for larger taps, like the one I have for smaller taps because each one of these holes took at least 15 minutes. Below is a shot of the first hole finished.
I then rounded up my SAF-AIR SA-187 fuel drain valves that will grace the bottom of the fuselage with their presence…. although, to be clear, they are quite shy so must be hidden away somewhat!
I then mounted the first fuel drain valve. As you can see, I needed the hole just a HAIR deeper since I want these drains to seat very close to the metal hardpoint.
I then mounted my first fuel drain valve to full depth.
Here’s a profile view of the GIB thigh support fuel sump drain valve.
A bit later I finished hole #2 . . . and mouned sump drain valve #2.
After a good bit I finished tapping all the holes with the 1/8″ NPT tap. I then cleaned up the 2024 aluminum piece in order to test mount all the drain valves.
I then mounted all the fuel drain valves that will be on my Long-EZ.
Here’s a profile view of all the fuel drain valves.
And, lastly, an “inside the tank” view of all the fuel drain valves.
Finally, today I dropped a small order with ACS for the remaining required fuel system fittings from the firewall forward.
18 May 2017 — I started off today by marking up the aluminum to cut out the individual hard point blocks for the fuel drain valves.
I had an issue that the only saber saw blade for cutting aluminum that I had on hand was quite dull from the last time I used it. I cleaned it up as best possible and tried it out since I didn’t want to take time out to go pick up some more. Well, the blade definitetly wasn’t optimal, but it was just enough to get the job done.
I then pulled out my big miter saw and cut down the line to free all the individual fuel drain valve blocks.
Later on the evening I Alodined the fuel drain valve mounting hard points.
19 May 2017 — Today fairly early on I got my 2 Holley Hydramats delivered. Again, each of these will go into the sumps that I will glass under the GIB thigh support.
Here’s a shot of them out of the box. I bought the 3″ x 8″ version.
Here’s yet another device that Dave B. brought to my attention. These very lightweight Optic-Electrical sensors warn of low fuel levels in the sumps and send that info to my EFIS.
Before heading out of for the afternoon & evening, I cut some scrap wood and mocked up my GIB thigh support sump setup. I used two ribs only because I was merely trying out the feel of the thigh support.
As I was cutting out the pieces for the thigh support, I wondered to myself what I was going to use as the top of the thigh support, which makes up the seat. With some scrap wood pieces lying on the ground I realized that I could simply use strips of wood Adirondack chair style and screw them in place.
Here’s another shot of the thigh support sump from the front looking aft. I have to say this is amazingly more comfortable than the original plans seat. I did note a couple of minor dimensional tweaks that I’m going to make, but I think my design is good.
20 May 2017 — Today I set my sights on the GIB thigh support sump tanks. My first quest was to ensure that I didn’t damage my embedded brake lines that traverse the bottom of the fuselage, one on each side. I placed a level along the outside of the fuselage and determined the distance that the brake line was away from the sidewall. I then marked the inside with an extrapolated, but close, measurement for the brake lines on each side… both using this method.
With knowledge of my brake line locations in hand, I could then more accurately draw out my thigh support sump design on the floor of the back seat.
Just as a point of historical note: these pics below are the last two pics showing the area on the seat pan that I was most proud of . . . and then destroyed! Such is the way of composite homebuilts eh?
Another quick side note: To implement my sump design I needed some 1″ Divinycell for a mini-bulkhead in the right front corner of the sump assembly. Well, I didn’t have 1″ pieces large enough so I micro’d these two pieces together to make this bulkhead piece, which I plan to use in the next few days.
I then put on my mask, drew a big breath, fired up my Fein saw and started cutting! Here’s the front border line of the sump(s) that I started cutting first.
I then cut the interim sides of the sump area. I moved the cutting lines in about 0.5″ to ensure I didn’t cut into the brake lines. I’ll then slowly moved my way out to ensure not to damage the brake lines.
I then cut the back line to complete the major glass cutting of this operation.
Then, using a utility knife, I slowly pried off the top glass of my GIB seat glass.
I then employed another power tool: an orbital sander and sanded down all the remaining high tops of the foam. It did a great job as you can see, but man did it produce some nasty dust…. and a lot of it too.
In the pic below you can see on the right side (top of pic) where I’ve started to remove the foam slowly under the fiberglass, about a half inch in. This is to ensure –again– that if I hit the brake line, it’s only by hand with a razor knife moving somewhat slowly. I did not however, encounter the brake lines which should be about where the top/right set of dashed lines are.
Having removed the foam from each side, I then carefully used the Fein saw again the trim away the half inch edge of glass. I then resanded the edges and in the forward outboard corners as well, which I obviously couldn’t get with the orbital sander.
Here’s a final shot of the freshly contoured GIB seat area ready to be glassed in prep for the thigh support sump build. You can also see in the pics below & above the marked locations for the sump drains.
21 May 2017 — Today I focused on the fuel sump drain valve hard points. I finalized their mounting locations and marked them up.
Before I got started in earnest on the inside of the fuselage, or moreover, mounted the drain valve hardpoint blocks in place, I needed to cut out a 3/4″ diameter hole in the bottom fuselage glass at each drain valve location. First, this will allow me to have the bottom skin cut away without any risk of driving a guide bit from a hole saw into the threads of the drain valve hard points.
Also, after the drain valve hardpoint blocks cure in place, I will sand the foam away to expose the majority of the bottom of each block. At the same time, I will also make a nice radius around each 3/4″ hole so that it transitions nicely with the bottom fuselage skin. I will then glass in 2 plies of BID onto the bottom face of the drain valve hardpoint block overlapping onto the bottom fuselage foam and finally around the curved edge and onto the bottom fuselage skin. This will get the drain valves tucked away nicely in case –God forbid– I had a catastrophic main-gear-ripped-off / belly up landing.
In addition, since I have Mike Melvill’s carbon fiber cowlings with armpit air intakes, I will need to fill in the bottom of my aft fuselage as if it had a NACA scoop (because Mike’s did and he filled it up with foam). Thus, right below the sump tank assembly and around/over the fuel sump drain valve attach divots, I’ll be laying up 1 ply each of Kevlar and BID. This will of course reinforce and protect both the fuel sumps and these drain valves.
I then finished cutting the foam out of the bottom of the sump tank (left & right) to embed the sump fuel drain valve hardpoint blocks. I also put plastic red caps into each block to protect the threads from the flox.
Then, not wanting a lot of hard flox & foam stuck to the bottom of each drain valve hardpoint block, I opened up the center hole going through the foam fairly wide.
I then whipped up some flox and mounted the right fuel sump tank drain valve hardpoint. I weighed it down to ensure the hardpoint and flox were nicely tight and compressed.
I also did the same for the left side.
22 May 2017 — I started out today by checking the fuel sump drain valve hard points that I had embedded into the floor with flox of what will be the respective left & right sump tanks. All looked good.
I then spent a couple hours doing some research and figuring out configurations on both the fuel system and oil heat system. I pulled the trigger on an order with Wick’s for some fuel system hardware and Adel clamps.
In the late afternoon I finally made it down to the shop. I cut 2 pieces of BID off the roll in my cutting table, both 10.5″ x 20″. I also cut one piece of Kevlar 9.5″ x 18″, since I wanted the Kevlar edges covered with BID.
I then pulled out the E-Z Poxy epoxy system that I will use for my fuel system structures, as per Gary Hunter’s suggestion. Now, if you’re wondering –again, as per Gary Hunter– why I’m using the 84B hardener vs the 87, well, that would be a good question. I guess simply because it came in a kit? I’m not sure. I double checked an email conversation I had with Gary, and in it he states that he refers to using 87 hardener because it was around long before the 83 or 84 hardeners, but any of the E-Z Poxy configurations will work. Whew! Ok, again, not sure why I went the 84 route, but glad that it gets Gary’s seal of approval.
Moving on, uh, er, perhaps not!
When I opened up my hardener it was literally a solid block of … stuff!
Since my buddy Marco uses this stuff I know that the hardener often crystalizes, making it unusable until you prepare it by first boiling some water, and then . . . Ugh, I’m just tired writing about it! Here, check out Marco’s blog for the inside scoop on preparing crystalized E-Z Poxy!
Thankfully, after 2 sessions of boiling and soaking my BRICK of E-Z Poxy hardener, it decided to join us again in a usable liquid form. Yay! Kind of a cool trick to do at childrens’ birthday parties and all, but seriously, when “I gotsta glass, I gotsta glass!” . . . ya know what I mean???
Alright. With my Using E-Z Poxy in the Kitchen adventures over with, I then whipped up some epoxy (ensuring to use the 100:44 weight ratio) and then some micro. I remember Marco having some gelling going on his epoxy cups, so I figured (and verified) that this 84 stuff is a lot less viscous than the other E-Z Poxy hardeners. [Hmmm? I also checked Marco’s blog and he’s using 84 hardener as well… what gives? Maybe it’s because mine was really warm from having just got out of its hot tub. Always good to have de-stressed hardener before going in on a big layup!] Anyway, not bad so far.
I then poured some micro slurry on the foam and got to work (sorry, bad pic!).
I then whipped up some thicker micro paste and hit the sides & corners.
I then laid up my first ply of BID using E-Z Poxy . . . look Ma! No hair dryer! haha!
And another couple shots of BID ply #1:
Ply #2 was the Kevlar, and I laid it up without any issues.
On all the plies, I would lay them up with a good amount of squeegeeing to get a good, air free bond between the top ply and lower foam/plies, then wet it out more to keep it nice and wet.
Here’s the final ply of BID to round out the glassing of the sump tank(s) floor.
I then peel plied the fuel sump tank 3-ply layup and added a bit more epoxy that I had whipped up to keep it nice and wet. I put the external thermometer transmitter next to the layup so I could track the curing temps.
Here’s one last –slightly in focus– shot of the peel plied fuel sump floor layup.
After cleaning up and grabbing a quick bite to eat upstairs, about 45 minutes later I then created MY own version of the Hell Hole! ha!
I set up my 2 heat lamps to keep my new addition nice ‘n toasty.
And covered it with a couple heat shields.
About an hour later I checked the layup to ensure all was going well, and that a heat lamp hadn’t decided to fall smack dab in the middle of it (or something!). Well, it looked good and the heat was at a decent level: about 19.8 when first back into the shop. Then it fluctuated up and down a bit over the 10 minutes I was in the shop: 120, then 119.7, then 120.4, as you can see below.
I figure 120°±1-2° is good. So instead of post-curing for 4 hours @ 140°, I’ll just let this thing bake for a minimum of 12 hours @ 120°. It will get post cured again, so no worries on that now.
23 May 2017 — I started off today assessing mounting hardware, components and configuration for the FT-60 “Red Cube” fuel flow sensor and the oil heat pump. I also reviewed my plan & sequencing for the sump build and all the stuff that needs to be mounted in the aft seat area.
Meanwhile, I checked the temp on the curing GIB thigh support fuel sump base glass, which appeared to have held steady at around 125° F all night long. This was the last check I did before taking off this afternoon to go visit some friends.
Before I left though I grabbed a fresh sheet of 3/8″ Divinycell foam and marked it up to cut out the front wall of the fuel sump.
Here’s a shot of the actual foam piece I’ll be using for the fuel sump front wall piece, next to the highly modified (from initial version) cardboard template.
I then cut 2 plies of BID out (one ply each for the front & aft side, respectively) and a ply of Kevlar for the initial ply on the aft side (interior) of the front wall.
After returning later this evening [including a couple of really good conversations with Nick Ugolini on a myriad of topics], I removed the heat lamps and started pulling the peel ply from the fuel sump base glass layup.
I have to say that at the seam of the peel ply pieces a fair amount of it was a bear to remove. After some perseverance I finally got the peel ply removed, although I’ll still hit that area with some good sanding to ensure it’s all good. I also took my razor knife and did an initial trim of the excess glass.
I then started in on glassing the aft side/interior of my fuel sump front wall. I started by whipping up some E-Z Poxy and then some micro slurry for the foam. After I got the foam surface micro’d, I then laid up the first ply on the interior sump wall: Kevlar.
I then laid up a ply of BID over the Kevlar.
Here’s a shot of the final 2 ply Kevlar & BID layup fully wetted out & trimmed for the fuel sump front wall interior side.
I then peel plied the layup (no peel ply pic except below) and set it under the heat lamps to cure. I had a fair little bit of epoxy left, so I slathered it on the top of the peel ply, so this guy was definitely laid up WET!
After I got the glassed front wall piece situated under the heat lamps, I then climbed underneath the fuselage and wrestled something fierce to finally pull the plugs out of the sump fuel drain valve hard points. I should have done it a lot earlier as the epoxy was at a good green stage, but I forgot so these suckers were in there good. But again, I prevailed!
24 May 2017 — I started off today checking out what was an extremely wet, epoxy-laden layup on the interior side of the fuel sump front wall.
I pulled the peel ply and trimmed the edges. Not too bad. I’ll probably leave the epoxy ridges unless they present a problem.
I started off trimming the fuel sump floor layup with my razor knife for a while, then grabbed my “Fein” saw to trim the remaining overhanging glass.
Although it doesn’t look that much different from above, I trimmed all the excess glass away. As you can see, I also took a few minutes to run the big yellow power cables back to the hellhole. I need these power cables ran so I can verify the size and shape of the front right side sump tank wall mount, since the front sump tank wall is essentially a bulkhead that goes from one sidewall to the other.
I then spent some time bending and shaping the left sump tank line to get it into place and flared with AN fittings to allow it to connect to the Holley Hyrdamat fuel intake.
In looking at these pics I realized that I should have done a zig or zag with my left fuel sump line to give a little elbow room for the right side fuel sump tank Hydramat. I’m not too worried since I’m sure I can finagle some space somewhere!
Here’s a shot of the left fuel sump feed line connected to the Holley Hydramat. Also, you can see the cured antenna cable channel layup in the back as well.
25 May 2017 — After finally getting back into the shop today, I figured it was time to drill out & clean up the currently glassed over fuel sump drain valve hard points. After carefully drilling the overlying glass and then cleaning up the holes, I then ran the 1/8″ NPT tap back through them to clean them up (although not a great pic, I wanted to show the general task).
I then did a quick install to check how the fuel sump drains looked and felt from both the outside of the fuselage and inside the fuel sump. Although these are –again– just a quick install to see how the overall fit is and if there are any problems, I’m already very happy with the elevation of the fuel drains. Once I clear out some more foam and dead flox, they’ll mount even farther up inside the outer skin exterior.
I had to use a light to get a shot of the right fuel sump drain valve.
Here are both drain valves together. Take note were that green line is next to the left drain valve in the foreground.
And here’s a pic showing a straight elevation shot from the left side of the fuselage looking right. And what can you see? If you look at that green line shown in the pic above, you can’t see the drain valves from the side. And again, these are very initial installs. Thus, I think the final installs will be exactly what I was looking for.
Here’s a shot of both drain valves protruding up through the fuel sump floor. I drilled these out now because when the sump walls get installed I figured it would be much more difficult to drill these out & clean them up.
Here’s the right sump fuel drain valve.
And the left sump fuel drain valve.
I spent a good half hour creating a wire template and then bending, shaping and cutting the fuel line that goes from the right sump tank up to the fuel selector valve. As I was finishing up flaring the front side tube for the AN-6 fitting, I though I should document my flaring the fuel tubing for a fitting, so here it is.
Below you can see the flaring tool ready to go on the aft fuselage floor. The tubing that I’m going to flare looks like a 3/8″ cobra ready to strike! In prep for flaring, I taped up the tubing on the front side in the pilot’s seat area to keep it upright.
Here I’ve clamped the tubing into the flaring tool. For every flare I ensure the cutting edge on the flaring tool gets a small drop of oil.
And here’s after I screwed in the flaring cone into the end of the 3/8″ fuel line tubing. If you look closely you can see the flared end of the tubing.
And here it is all nice & clean after I removed the flaring tool.
And with the sleeve up nice & snug with the flared tubing.
Finally, here’s the nut in place and the fuel line ready to be installed.
Again, I just flared the right fuel line tubing that connects the Holley Hydramat fuel feed to the right intake on the Andair fuel selector valve.
Here’s another shot of both left & right Holley Hydramats connected to their respective fuel lines.
With all the fuel lines completed (as far I need them to be thus far) I could then configure the front right corner 1″ thick Divinycell foam piece that will make up the right front sump wall extension that actually connects the thigh support fuel sump to the right fuselage wall. I needed the fuel lines to be completed so I could know how to configure them in & through this block of foam. I also needed to account for the 2 big power cables that weave their way through the length of the fuselage from nose to engine compartment.
As you can see, I cut a groove for the 3 fuel lines and little notch that will allow me to thread the big power cables through this bulkhead later on. Again, the sump front wall piece that I just glassed will tie into this piece and make up the front sump wall & mini bulkhead across the fuselage at this point.
Moreover, once I configured the right front sump wall extension piece, I was then able to measure the exact length of the fuel sump front wall piece that I had just glassed yesterday, and trim it down a bit.
Also, as you can see in the pic below I made a couple of channels in the foam to run Nylaflow conduits for the sump low fuel alarm sensor wires for each side.
I added a hole in the upper right hand corner of my fuel sump right side wall extension piece for the routing of all the wires heading back to points aft that ARE NOT the 2 big power cables. I cleaned up the foam and prepped it for a 1-ply BID layup.
After micro’ing the foam surface, I then laid up 1 ply of BID on top and then peel plied it. Tomorrow I’ll do the other side.
26 May 2017 — Today I started out by trimming the right front corner piece of the fuel sump’s front wall extension. I had glassed the aft side last night, and now I trimmed it up in prep for glassing a ply of BID on the front side. I did leave the glass over the channel in the middle alone for now just to maintain a little bit more strength in the piece while handling it.
I then micro’d up the foam and laid up 1 ply of BID on the front side.
27 May 2017 — Today I crossed the proverbial Rubicon in my initial steps of the thigh support fuel sump by glassing the fuel lines into place.
I started by prepping the fuel sump right forward wall extension piece to get it installed tonight. This may seem like not such a big deal, but this piece is a major lynch pin to the entire fuel sump build. Not only is it a part of the front wall –making the front wall a bulkhead by traversing from one fuselage sidewall to the other– but it also ties the sump to CS118 for added strength. Finally, it secures the 3 fuel lines heading aft: one to each sump tank and the other to the engine.
One of my tasks was to make foam fuel line mounting brackets that –at least the bigger one– will need to be glassed in place when the fuel sump right forward wall extension piece gets glassed in. I’ll most likely wait on the smaller bracket. If you’re wondering why I went with foam and am using fiberglass to secure the fuel lines, I actually got the idea when I queried Nick Ugolini on it.
To use Adel clamps, I would have had to spread out the fuel lines much farther apart (unless I grouped them together, which was not something I was so keen on doing). Plus, the way the fuel lines go through the pilot seat back opening, they either have to have a significant bend or slant to get them to the sidewall an inch away to use the Adel clamps, or they still need some type of bracket built to provide the required standoff from the sidewall.
Yes, if my “map” pocket wasn’t installed I could have possibly drilled or removed the edge of the pilot seat back that sticks out from the sidewall, but I wouldn’t prefer to do that anyway . . . and of course it’s not an option in this case. To be clear, I have been researching this topic online and talking to folks for over a week now regarding the securing of fuel lines, and when Nick mentioned this, it was simply an Aha! moment.
After a grinding few hours, here’s the final glassing-in of the fuel sump right forward wall extension piece. Obviously in the pic you can see where I’ve also 5-min glued the right armrest storage pocket. As for the sump wall extension piece, I floxed it in place first after sliding the 3 fuel lines into the initial slot I created on this 1″ thick Divinycell extension. I then used a clamp as a spreader to keep the extension piece firmly pressed against the right sidewall. A bit later I had to remove the clamp for a bit while I mounted the foam fuel line bracket, but then it went right back into place.
I used a couple of pieces of the original foam I cut out of the wall extension piece to place back under the bottom fuel line. To lighten up the fuel line install I resorted to using flocro with a bit more micro than flox. I flocro’d the bottom foam piece back into place under the bottom fuel line, then had to add another 0.4″ thick foam piece to get the height correct. I then slathered up the channel for the middle fuel line with flocro and added a 0.35″ foam spacer between the first and second fuel lines. Again, I added more flocro and then another 0.40″ foam spacer between the middle and top fuel lines. Finally, I closed up the space above the top fuel line with another foam piece flocro’d in place. The top fuel line has a tad more space between it and the middle fuel line to provide just a bit of clearance for the fitting that’s right there.
Once I knew the wall extension piece was securely in place, as were the fuel lines, I then carefully used sandbags to weigh down both fuel lines going to the Hydramats in an effort to have them cure in the correct position. I of course am hoping that there is minimal spring back and that this works . . . to make it easier when mounting the middle and right side walls. Not a huge deal if they don’t, but again, it would make the upcoming wall installations easier.
Besides using 2-ply BID tapes to secure the sump wall extension piece to the right sidewall & fuselage floor–respectively, I also laid up 2-ply BID tapes between the CS118 mini-bulkhead and the sump wall extension, also on both the front and aft sides.
In the pic below you can also see the foam fuel line bracket that I floxed & glassed in place. For this I simply used 1 ply of BID on each side. After I ensure the fuel lines are in the correct position, tomorrow I’ll secure each fuel line in place with flox in its respective notch, then I’ll layup a 1″ wide ply of BID over the entire edge of the fuel line bracket, from floor to sidewall. I’ll most likely mount the other fuel line bracket, and probably even get the fuel lines nice and situated, then mounted at the pilot seat bulkhead opening.
28 May 2017 — This morning when I happily went down to check out my layup, I didn’t stay happy very long. As I was ripping off the peel ply, which is admittedly one of the best ways to start out a morning, a couple of areas still seemed a bit soft and not fully cured. This was not really what I was expecting since I had used fast hardener. Ironically, I had just had a discussion within the preceding days on fast hardener, as I extolled its virtues.
There is of course a possibility that I jacked up the ratio, but I am usually pretty good at ensuring those are correct. Regardless, I decided to cook it for a while and set my sights in at a good post cure temp: 140° F for 4 hours. Over the next couple of hours I checked various spots and never had the IR thermometer go past the mid 150° area, and only in a couple spots. And I was checking just about every area in each heat lamp’s path (more on this below).
Besides the heat lamps, in this pic below you can see that I glassed the aft side of the GIB armrest storage pocket with 2 plies of BID.
Below you can see the yellow spot again. After establishing that my average temps on all the stuff I checked being in the heat area, including the sidewall and the storage pocket, were in the high 120s to high 130s, I ran out to grab a bite to eat and go to the store. When I checked the heat lamps a bit later I saw this discoloration. I immediately checked the temp as I was pulling the lamp away, and it was 162.9°. I also did a quarter test and could find no delamination. Since a good portion of the yellow will get cut out when I open up the sidewalls for the baggage area, I’ll check the foam & glass again then. But for right now, nothing seems odd except the color change. Moreover, MGS 285 epoxy should have a multi-hour post cure over 170°. I guess just that high of heat concentrated on that one spot over time caused the discoloration.
Moving on. Note that the right front sump wall extension piece layup is complete! The heat lamps did there job and the spots I was concerned about cured nicely . . . except one.
The area on the aft side of the foam at the bottom didn’t seem to be fully cured. If this were slow hardener I wouldn’t have worried about it, but since the other areas were cured, this concerned me. Now, it still looked like a solid layup, but the overhanging glass was just a bit too pliable for my liking. I decided that in the 1 inch area that I would be laying up the BID tape for the outside of the right sump wall, that I would remove this glass. Since I had laid up 2 plies over just the one on the sump wall extension, I broke through to foam in a couple spots. No worries. I’d rather have fresh foam for the next layup then putting good glass over some that is a bit suspect. As for the rest of that layup, it’s in there and sticking, but I have so much other glass around it, I’m not concerned if its strength is a little less than normal.
In the right pic you can see the front side of the layup.
I wanted to show the access holes on the outboard side of this layup: the top hole is for the bundle of small wires that will traverse this bulkhead heading back to the aft areas of the plane. The bottom hole is for the 2 big power wires to go through.
You can see that I also made the big power wire channel on the foam fuel line bracket as well.
So here’s a shot of all the layups I did last night, after I cleaned it all up. One good thing that happened is that weighing down the fuel lines worked. The fuel lines are in the correct position and have no tendency to try to rotate upwards.
I then finalized my dimensions and shape for the fuel sump profile. I took some scrap 3/4″ thick Divinycell foam and cut the pieces for the left & right sump walls. I then micro’d the pieces together.
I then cut out the middle sump rib from 3/8″ Divinycell foam. I loaded everything in the backseat for a quick mockup to see how it all looked & fit.
I figured out the fit on the middle fuel sump rib as well. If you’re wondering why the bottom of the middle rib is cut, there is a technical term for that: it’s called being unfocused, not concentrating on the task at hand and having a major brain fart! I noted on the left side wall that the base of it matches the base of the front wall. I then inexplicably picked up the middle rib and had it cut and was putting it back in to check before I even realized the mistake I had made! Luckily, this is foam and composites, and it’s all easily fixed!
I started with the interior left wall and laid up the first ply, which is Kevlar.
I then laid up 1 ply of BID on the interior left wall (ply #2), and then –after reattaching the bottom strip– I laid up 1 ply of BID on the left side of the middle fuel sump rib.
I then trimmed the overhanging glass down.
And peel plied the layups.
Previously, I had laid up the forward side of the GIB armrest storage pocket with 2 plies of BID and a 1″ strip of BID down the front face of the foam fuel line bracket. I then checked those to ensure that they were good to go.
Finally, since my garage is in the low 70’s I decided to put the freshly glassed sump wall pieces under heat.
Then I realized it was a bit too much heat and turned off one of the lamps and moved the sump wall pieces a bit farther away.
29 May 2017 — I started out today by pulling the peel ply and trimming up the edges of the layups on the wall sides that essentially make up the left sump tank, left & middle walls.
I then promptly glassed the right side of the middle wall, or sump rib, with E-Z Poxy to get it curing.
I then glassed the outside of the left sump wall using MGS, since this wall will not be in contact with fuel… hopefully!
When I did this layup, I also glassed a strip of BID on the bottom of the GIB right armrest storage pocket going to the sidewall. Once cured, the GIB storage pocket will be glassed in once and for all.
Here I’m about halfway through the process of fitting the right sump wall to the sump / fuselage floor.
And here’s when I finally got the shape along the bottom of the sump right wall dialed in.
Here’s an aft shot of the fuel sump’s right wall. Note that you can also see the fuel pulsation damper mocked up in these pics as well.
Once the shape of the right wall was good, I glassed it with a ply of Kevlar first, then a final ply of BID, just like I did with the inside layups of the other walls that make up the exterior perimeter of the sump tank.
One thing I was going to account for that slipped my mind until after I hurriedly glassed the interior side of the right sump wall, was that this wall needs to be a bit shorter due to it butting up against the back side of the right front sump wall extension. I was so dialed into getting the difficult shape on the aft side of the wall completed, that I missed the front edge needing to be back 0.55″. Since I had already configured the right side wall, I was going to merely trim the aft edge so it’s profile would match the other 2 walls. But again, I jumped the gun in glassing the right sidewall so I didn’t get it done.
Fast forward many hours later, and I marked the left wall with 0.55″, aligned the two sides and then marked the aft/top of the right sump. I trimmed the right sump wall immediately after this pic was taken.
30 May 2017 — I started off today glassing the outboard/exterior side of the fuel sump’s right wall. I then peel plied the 1-ply BID layup.
I also pulled the peel ply and cleaned up the layup on the right side of the fuel sump’s middle rib. After I cut the notch for the left sump fuel line access, this will be ready to install.
Quite a few hours later I pulled the peel ply, knife trimmed and sanded the edges on the outboard/exterior side layup on the fuel sump’s right wall.
I finally decided after assessing the oil heat feed and return lines that I am going to run them through the fuel sump front wall’s left extension tab. There won’t be a lot of space for working and mounting these lines, but once in they should be good for quite a while. I was going to use 1/4″ Finnish Birch plywood, but since I have some spare bits of H250 high density foam on hand, I decided to use it instead. I made two hex holes in the H250 to flox in the AN -8 (1/2″) to AN -6 (3/8″) reducer fittings. This is required since the oil heat exchanger only comes with -6 fittings, so at some point each of the lines needed to be reduced/expanded to work. And that point is here, about a foot away from the heat exchanger.
I then micro’d in the H250 reinforcement foam and also the 3/16″ Nylaflow lines that the low fuel sensor wires will use to exit the front fuel sump wall. To be clear, I didn’t put in these Nylaflow lines just to be fancy or make it look cool. I wanted to ensure that these wires in an area that is subject to feet sliding against it –literally every time the GIB gets in or out of the airplane– were protected.
I then laid up 1 ply of BID across the entire front face of the fuel sump front wall. I also added a reinforcement ply of BID both over the left fuel low level sensor mounting point, and all around the entire Nylaflow line area, which includes the right fuel low level sensor mounting point.
When I glassed the aft / interior fuel sump side of the front wall, it had a distinct bow to it afterwards. I wanted to get the fuel sump front wall as straight as possible, to facilitate ease of glassing it in, so I weighed down each side with taped 2x pieces of wood with a 5-pound weight on each one. That should do the trick!
I actually did this earlier in the day, but since my blog posts are getting a bit long, I decided to put it here for topic flow. To finalize the fuel line installation from the Pulsation Damper aft into the Hell Hole, I need to know what clearance I have. Yes, knowing how to get around or skirt by the GIB right armrest storage pocket is great, but there’s another factor at play here: the armrest itself. I decided a week or so ago that since I had fuel line fittings that I may need to get to after the plane is operational (plus, 98% of my wiring runs are on that side) that I should make the right GIB armrest removable, so I did (see Chapter 16 for armrest installs).
For the final push of the evening, I then set my sights on cutting out the fuel line notches in the fuel sump right wall and middle rib. Below you can see that I’ve struck gold! I started on the freshly glassed exterior side of the right wall and started removing the plug that provides access to get the fuel lines into the wall before the plug goes back in, and it all gets slathered with all varieties of flox –slurry, wet, paste, dry– and sloppy wet bid tapes.
Here you can see the lower foam/glass plug in place that will help seal up the fuel line access hole.
I then did pretty much the same thing with the middle rib/wall by cutting out the access notch to slide the rib in over top of the left fuel line. Again, I configured the left fuel line going through the right sump tank to support this oft heard statement when flying: “Passengers: Please keep the aisle clear of any fuel lines!” . . . yes, in short I didn’t want any high-heeled Vixen (you know who you are!) digging their heel into my fuel line, or any of my other ham-fisted, Neanderthalic friends (and you guys know who you are too!) doing the same —well, Good Lord, hopefully not with high heels! … haha!
Here’s one last shot of all the fuel sump walls glassed and ready for install. With the front side of the fuel sump wall curing tonight, I should be ready to start assembling this beast within the next day or so.
31 May 2017 — Today I took the 2x boards and weights off the end of the front side BID layup on the fuel sump front wall. I have to say, the weights worked great to straighten out the sump front wall.
I pulled the peel ply and razor trimmed & sanded the edges. I then cut out the hex holes on the left side of the wall for the oil heat line reducer fittings. Also, I drilled the two 11/16″ holes for the low level fuel sensors. Finally, I added a spot of micro in the areas where I had the toothpicks holding the Nylaflow in place.
I then test fitted both the oil line reducer fittings and the low fuel level sensor fittings.
I ran out to Harbor Freight today to get my new “Fein” saw, which has increased in cost by a whole $5! (bummer). I picked up a few other things I needed for the build and headed back home. The traffic was unusually heavy today, so it took well over an hour longer than I expected.
Upon returning home, I checked out the new “Fein” saw and actually used it to cut a small notch in front right sump wall extension piece that will adjoin the front wall piece that I’ll be glassing in… the notch is for the 2 Nylaflow lines so that they can smoothly transition out of the wall. BTW, if you caught the Nylaflow lines’ positions, you may have noted that they are at the same level (waterline) as the small wire bundle that will be traversing down the side of the fuselage (as could be ascertained by where I drilled the hole in the front right sump wall extension piece). Thus, the position of the Nylaflow puts them in the perfect spot to merge right into the small wire bundle.
After I sanded and prepped all the areas that would be receiving glass, I then spent a good 45 minutes cutting Kevlar, BID and plastic to make up BID tapes and a BID/Kevlar tape for glassing in the sump front wall. After I got all the prepreg setups ready, I mixed up some E-Z Poxy epoxy and wetted out the first few BID and BID/Kevlar tapes (the one with Kevlar went on the inside of the tank along the junction of the floor and the front wall).
Over the next 3 hours I proceeded to glass in the fuel sump front wall.
It’s definitely not the prettiest or smoothest layup I’ve done, but so far I think it’s solid as far as meeting fuel tank requirements. Here’s a shot from the front looking aft. I should note that I placed the left sidewall piece in its spot merely for spacing & alignment, and if you look closely enough you can see that I put a nail through the top corner of the sump sidewall into the sump front face to secure it.
To make things EZ I of course used E-Z Poxy on the entire layup, including the left side extension tying the sump front wall into the left sidewall. After I got all the BID (and Kevlar) tapes laid up, I the peel plied all my layups and took care to keep the internal tank layups very wet. You may have noticed that the outboard sides of the inside corner tank tapes seem to curve up (i.e. “smile”), while towards the center it “droops” down. I did this on purpose to not completely cover up the fuel drain valve holes.
1 June 2017 — Today I started out by cleaning up the 2 oil line reducer fitting mounting holes in what makes for a mini-bulkhead for the pair. I then test fitted the oil heat line reducer fittings in the holes.
I spent a good bit cutting out 4 prepreg setups of BID and BID/Kevlar tapes for the sump left wall installation.
Here are the tapes wetted out with E-Z Poxy.
I then floxed/micro’d and glassed the sump left wall into place.
I then peel plied all the sump left wall install layups.
Another shot of the sump left wall install. Immediately following taking this pic, I threw these layups under heat lamps.
I then pretty much repeated the process — sans Kevlar, and a second ply of BID– to flox in and layup the corner tapes to install the sump middle rib.
Here’s a closer shot of the flox & BID around the left tank fuel line coming through the sump middle rib.
And a shot of the other side.
And finally, a shot of both outside walls and middle rib. As of now, I just have the right wall to install.
And here’s a shot of the fuel sump left wall after I pulled the peel ply and cleaned up the layups.
Part of that cleanup included, once again, cutting the freshly laid up glass out of the oil heat lines reducer fittings.
2 June 2017 — Today I finished installing the vertical components of the thigh support fuel sump by glassing in the sump right wall. As with the left wall I used 1 ply BID and 1 ply Kevlar on the interior tapes, and 2-ply BID tapes on the exterior side — all with E-Z Poxy.
Here’s a shot from the aft side of the fuel sump right exterior wall.
I went to visit some friends and about 8 hours later I returned home, pulled the peel ply, and then cleaned up the layups a bit.
Again, here’s a shot from the aft side of the sump right side wall.
I then checked the fit of both Holley Hydramats, which were spot on. You may note that in the pics below I also installed the fuel drain valves to check fit and clearance with the Hydramats.
I was curious about the amount of fuel these fuel sump tanks will hold so I worked up a quick estimate which comes up to about 1.3 gallons each, so around 2.6 gallons total combined fuel in the fuel sump tanks.
3 June 2017 — Today I started by cleaning up both sump tank sides with a bunch of sanding to remove the peel ply boogers, dead glass and cut down the ridges at the glass intersections. I also wanted to ensure the floors got a good sanding, with all the shiny spots removed in prep for the micro pour I’ll be doing on each side to cause any potential water in the tanks to flow outboard and forward to the fuel sump drain valves.
In addition, I looked around for some good material to make a dam to layup a ply of glass on the aft side of the left sump tank –starting out– then after the poured micro has cured I’ll use the in place dam for the right sump tank.
After not being able to find anything, I went to the usual aviation departments at the various stores. Finally, at Michael’s (arts & crafts) I found some balsa wood that was thin, flexible but strong enough to keep its shape. So I bought it, came home and resumed my build task after my multi-hour mini quest.
I then prepped the balsa wood by notching each aft corner so that it’d fit in place, then I taped up the front side with clear packing tape. I then attached a piece of 3″ wide peel ply across the front by taping it at each end.
Here’s a not-so-great shot of the peel ply, which you can just make out the edge of at the top of the dam.
I then finished securing the dam with tape, and one small finish nail in the center. I also placed a couple of sandbags pressing against the aft side of the dam to keep it nice and tight against the aft edges of the sump walls. The middle rib dips forward just a bit which is fine because I actual wanted a bit of a dished shape for a better seat contour. But really, it’s not much at all. [Also note: the dam looks really askew in these pics, but it must be the camera angle because the sump sides are not different lengths as it looks to be portrayed in these pics].
I then mixed up a bunch of micro and stuffed it down in the corners along the intersection of the dam and the sump floor. I then laid up 1 ply of BID onto the floor and dam front face (leaning forward) and also overlapping a bit onto the sidewalls. I then let the layup alone to cure for a few hours before pouring in the micro floor contour. Again, I am only laying up one side at a time to allow each layup to cure a bit before pouring in the micro, thus alleviating having to peel ply one side since I need to jack up the plane in a certain configuration for the floor to be “level” and cure to provide a correct flow.
I also cut to length and then taped up the bottom side of a 1.5″ wide Aircraft Spruce shipping board with clear packing tape before mounting it on the front top edge of the sump, overhanging aft over each sump tank an inch from the front sump wall. After creating a micro fillet in the front top corner, I then laid up 2 plies of BID on the underside of the board overlapping onto the top aft of the front wall, and a little bit onto each sidewall. This 1″ overhang will create a “top cap” that will give me more area to flox the sump top on before glassing the outside of it to the external sides of the sump.
I then went to dinner with a buddy of mine, and upon returning –at the 4 hour cure mark– I placed a 4×4 under the left wheel and one under the front wheel as well. I then whipped up some E-Z Poxy and made some wet, just soupy, micro. I needed 2 batches to get the micro right and I had to adjust the elevation of both the front and left side of the aircraft to get the micro to spread out towards and up to the fuel drain valve.
I have to say pouring in the micro soup was a bit of a compromise. I used as much micro as I could to lighten up the epoxy in the micro pour, but it took a fair amount. I did’t originally shape the floor for water runoff aggressively at the beginning since I wanted A) the floor to have some depth to it to allow the installation of the fuel drain valves up deeper into the belly skin, and B) I needed to be careful around the outboard sides of the cutout floor foam because the embedded brake lines were very close to the outboard edges of the newly created fuel sump floor.
The consequence of all this is that I estimate I lost about a third of a gallon in volume tonight by pouring this micro in place, leaving me with about 1 gallon in this sump tank. Obviously, this leaves me with an estimated 2 gallons total in the sump tanks if this plays out the same on the right side. I will of course have to confirm the actual capacity of each sump tank after I get them built.
4 June 2017 — I started off today by popping off the 1.5″ taped board that I was using as an overhanging mold for the 1″ top lip for mounting the top of the fuel sump.
I then trimmed the overhanging top lip at 1″ wide using my new “Fein” saw.
I micro’d up the aft floor to dam intersection on the right sump tank and then laid up 1 ply of BID into the intersection, overlapping onto the side walls. The pic for the layup turned out terrible so I didn’t include it here. Of course I used E-Z Poxy.
About 4 hours later, with the glass still tacky and only about halfway cured, I jacked up the right side of the plane and the nose wheel and then poured micro into the right sump tank to create a slanted floor up to the right drain valve for water collection. I think I used slightly less micro and didn’t post cure it quite as long as the left side, thus the striking color difference between the 2 sump tank floors.
5 June 2017 — I started off today by pulling off the dam form/mold from the bottom aft side of the sump walls.
Here’s a closer up shot of the glass layups and micro with the peel ply still in place.
I then pulled the peel ply.
And spent a good while cleaning up the micro junk left over.
I then aggressively sanded the micro and gunk at the bottom aft side of the sump walls before trimming the glass that creates a mini wall at the bottom aft of the fuel sump.
I then stuck on a new piece of 32 grit sandpaper onto my hardboard and went to town on the upper lip since there was a decent ridge over on the left side that was about 1/8″ higher than the top edge of the sump front wall piece. I got that all evened out and the lip close to being ready for the future floxing on of the sump top.
I then ginned up some E-Z Poxy, whipped up some micro and made some corner fillets next to the fuel drain holes to ensure that any water in the sump tanks didn’t shoot past the hole and merely sit in the corner pockets. This of course is analogous to what is done with the fuel drain on the main tanks.
Here’s the right sump tank corner micro fillet.
And the left tank.
I then used the epoxy I just mixed to make up some flox to install the right low fuel sensor fitting into the front wall of the right sump tank. I placed each of the low fuel sensors in the center of each tank, both almost 2″ down to keep them from constantly ringing off with false alarms.
I then marked up the Vance Atkinson designed main tank fuel pickup port to be used in configurations where no external fuel sumps are employed. The other major design for this type of fuel pickup is from Ken Miller, who calls for a cigar tube shaped pickup that sticks out into the fuel tank right at the fuel tank floor level (both designs have the fuel tank floor foam removed in the immediate area of the fuel pickup port, with just glass-to-glass contact for better fuel flow into the pickup port). Since Ken’s design calls out for fittings to be used, I opted for the simpler and cleaner (again, IMO) design of Vance Atkinson’s — albeit, to be fair I could have used Ken’s design sans fittings, but obviously went the Atkinson route.
The design for the fuel pickup port, again, is pretty darn simple and straightforward. It calls for the glass and foam to be removed from the tank side into the sidewall until the interior fuselage glass is reached. Then a straight bottom “shelf” is created, with an “alcove” above it for fuel flow. I determined the top edge of the left fuel tank floor and then marked it. I then marked up the alcove portion of the left fuel inlet port.
I then spent a good 2 hours of sheer knuckle-busting, finger-slicing pain in getting the 1/2″ fuel line run from the internal side of fuselage up to the left fuel tank inlet/pickup port. I was then able to coax just enough of the fuel line out to flare it to create a nice pickup funnel affect.
Here’s the interior portion of the left main fuel tank to left fuel sump tank feed line.
I then went through a smaller version of the pain I experienced before to install the 1/4″ left fuel sump tank vent line from the main tank down to the sump.
Here’s a shot of the left 1/2″ main tank fuel feed to the left sump tank, the 1/4″ left fuel sump vent line, and the oil heat return line which I added a couple of layers of heat shrink to reduce any radiating heat affect.
I sealed up the opening of the main fuel pickup tube at the main tank opening, then mixed up some more E-Z Poxy and made up some wet flox. Then, using a syringe, I slowly injected flox on all sides of the fuel pick up line. You can see the dark line where it filled in the spacing around the fuel feed tubing in the fuselage sidewall. BTW, this area will get covered with a ply of Kevlar to protect that fuel line from any sharp dings or blows to the external wall of the aircraft (as will the glass-to-glass bonds in the fuel pickup area of the main tank).
I then laid up 1 piece of Kevlar inside the alcove of the fuel pickup port, and then a ply of BID over the Kevlar, overlapping onto the fuselage (future fuel tank) sidewall. In the second pic you can see the fuel pickup tube after I floxed it in place and glassed the area in the alcove above it. I’m leaving the area around the fuel pickup tube raw flox for now since the exact elevation of the sidewall will need to be matched to the fuel pickup tube level. Moreover, in both pics you may note that I’ve placed the top of the fuel pickup tube around 0.25″ below the cutout line. This is to get the fuel pickup line close to what will be the level of the glass-to-glass floor of the main fuel tank.
I then floxed around the inside entrance into the fuselage of the main left tank fuel feed and the sump fuel vent. After floxing these lines in place, I then laid up 1 ply of BID over the entrance hole.
Here’s a closer shot. I wanted to point out in the upper left of the pic that the external tank side fuel pickup port is just visible (note the yellowish area).
Finally, as the initial round of glassing on the left tank main fuel sump feed line & vent was complete, I then took a few minutes to pull the protective tape off the right low fuel sensor fitting that I floxed into the front wall of the right sump tank. I cleaned up the flox a bit before calling this fitting install good.
6 June 2017 — Today was a light build day, but I did pull the peel ply and do a quick cleanup on last night’s layups on the left main tank fuel pickup that feeds the left fuel sump tank.
I also pulled the peel ply and cleaned off some peel ply boogers from the internal fuel sump feed from the main left tank and the sump vent line to the main tank.
7 June 2017 — Today I started on the right main tank fuel pickup port by marking it up & then cutting it out. I then shaped the foam on the inside of the fuel pickup port ‘alcove’.
I then marked the inside of the fuselage where the right main tank to right sump feed line will enter into the fuselage. The point on the right side is much higher than the left making the amount of fuel line tubing having to traverse through the sidewall much less than on the left, so the process was significantly easier in running this line.
I then drilled and widened the hole to the point it would accept a 1/2″ fuel line.
I also worked on the external side to ensure the 1/2″ fuel line could be routed into place.
Here’s a shot after I routed the right main tank fuel line feed and flared it to create a nice pickup port, and also the 1/4″ vent line that I ran from the sump.
Here’s a shot of the right main tank fuel line feed and the sump vent line (and the engine fuel feed line).
Here’s a wider angle shot showing the right side fuel feed and vent lines to the sump.
I finished up the evening by prepping to glass the right side main tank fuel pickup port, but first I used some micro to secure the left side fuel sump vent line and laid up 1 ply of BID over it.
I then glassed the right side main tank fuel pickup port and the fuel sump vent line.
8 June 2017 — Today I started out by pulling the peel ply off the layups from last night. I cleaned up the peel ply edges on the 1 ply BID that I used to cover the right main tank fuel sump feed ‘alcove.’ I did have to spend a good 20 minutes on cleaning up the opening of the fuel tube because my protective tape didn’t stick so well and left some untoward flox in places it was not supposed to be. Fun.
I then got ready to flox the main tank fuel feed lines into place at the top forward edge of each sump sidewall. I cut & sanded the troughs in each wall to accept the tubing, but before I could proceed on the right wall, I needed to mount the fuel pulsation damper in place to avert a more difficult install later on.
I actually went back upstairs and brushed up a bit on installation techniques & methods before diving in. Also, on a FaceBook post a few weeks back, Nate Mullins stated that he had used DEL fitting seals with very good results, and since I was getting ready to submit an Aircraft Spruce order, I put them in the basket…. talk about good timing, eh?!
Here’s a closeup of a DEL fitting seal.
After getting the pulsation damper mounted, along with the fuel line traveling aft from it to the engine (via the FT-60 ‘Red Cube’ fuel flow sensor), I then floxed in place the main tank fuel feeds to each sump tank & the sump vents. After I got the flox set where I wanted it, I then peel plied it to match the top edge of the side walls fairly closely.
In addition, if you look closely in the pic below, you can see that I floxed a Clickbond in place for the fuel pulsation damper Adel clamp.
Here’s a shot of the left fuel line feed into the sump along with the fuel sump vent.
And here’s another shot of the right fuel line feed into the sump and the fuel vent. Also note that the engine fuel line feed is now permanently mounted.
With the leftover flox from mounting the fuel line feeds in place, I marked up the left GIB armrest with 3 attach points. I then marked the mounting hole locations of those 3 attach points, hollowed out the foam to create a hardpoint divot at each spot, and filled it with the leftover flox. I also did one more hardpoint in the same manner on the aft side of the right GIB armrest [no pic].
I then spent a bit sanding down the aft sump 1-ply BID layup that I put in place by utilizing a dam. The corners especially needed a bit of work, but after some diligent sanding I finally dialed it in.
I then prepregged 1 ply of BID and laid it up after filling a few holes with micro. This layup completely covers the glass dam that I laid up before, and overlaps onto the fuselage floor (GIB seat pan) by an inch. I then peel plied it and slathered a bit more with E-Z Poxy to ensure the layup was good & wet.
9 June 2017 — Today I started off by pulling the peel ply from both the floxed in fuel & vent lines at the front, top side of the fuel sump outboard walls, and aft side mini-wall that I created in order to be able to contour the sump bottom with micro.
I then made this video providing an overview thus far on my fuel sump & fuel system. I also do a water flow test using a marble, which I momentarily misplaced, hence the blog title.
I then laid up 2 plies of BID over the fuel pulsation damper Adel clamp click bond.
And 3 plies of BID over the 3 click bonds that will secure the FT-60 ‘Red Cube’ fuel flow sensor bracket to the Hell Hole sidewall.
Speaking of which, here’s the bracket for the FT-60 ‘Red Cube’ fuel flow sensor right after I drilled the 3 lightening holes on the lower portion of it.
And here’s the FT-60 ‘Red Cube’ fuel flow sensor bracket set in place after the click bond BID cured. There is some gunk at the base of one of the click bonds that I need to clean up so that the bracket will mount fully onto the click bonds, but I’ll save that until tomorrow.
Something I didn’t get a pic of was my work on the fuel sump cover. I spent a good hour shaping it before putting weights on it and then heating it up for a good bit with a heat gun. I then let it cure for a good while as I went out for a bit.
12 June 2017 — 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.
14 June 2017 — Today I spent well over an hour mocking up the fuel sump tanks’ access ports, determining both size and shape and testing them out. I finalized an oval shape with an access hole of 2.5″ high x 4″ wide. These access ports will allow me to initially install the Holley Hydramats when need be, inspect them during annual condition inspections or whenever necessary, and swap out the mats in 5-10 years as required. I also determined the width of each interior 0.040″ thick mounting ring to be 5/8″ (0.625″). These are the rings to which the covered nutplates will get attached.
I then made up templates of the fuel sump access port mounting rings and covers in PowerPoint and printed them out. After some judicious sanding on the sump top, I then measured out the access port locations and marked up the sump top.
15 June 2017 — Today I started working on the fuel sump access ports. I had determined last night the nutplate attach ring that goes on the interior side of the tank was just a bit too wide, so I reduced the width down to 5/8″ from 3/4″. I then spent some time spacing out the 7 nutplates equidistant on the ring and marked them up.
From the rivet holes on each nutplate I then determined the actual center for each one & marked it.
Using my paper template, I then transferred each sump tank’s access hole onto the sump top piece of foam. I also marked the outer edge of the ring (and each sump access port cover) with a dashed line.
I then cut out each sump tank’s access port hole and set the foam top back over the sump tanks. So far, I’m very happy with the configuration and spacing of these access holes.
I then cut out the access port covers out of 1/16″ (0.063″) 2024 aluminum.
Since it got too late to be cutting metal in the shop this evening, I just went ahead and marked up the sump access ports nutplate rings to be cut out tomorrow. I’ll be using 0.040″ 2024 aluminum for the nutplate rings.
16 June 2017 — 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.
17 June 2017 — 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.
18 June 2017 — Today I started off by shutting off & pulling the heat lamps from the sump top interior layup post cure. I then slowly and carefully pulled all the weights off the top. I then carefully worked the top off of the lower sump walls and flipped it over to inspect it. All the glass was in good shape.
The only minor issue I had –unintended consequences– was that the BID that was securely in place in the “pockets” around each access hole separated off the foam surface slightly in a few areas. I’m thinking that in the depressions for each access hole, they probably pulled out just a hair in those few areas because I pulled the glass slightly taunt around the holes by weighing down the entire sump top foam plate with weights. No major worries. A bit more work and assessment, but still very workable.
I then proceeded the quite understated process of pulling peel ply, cleaning up the peel ply edges and trimming the glass overhanging the perimeter edges with the Fein saw. This entire endeavor took nearly an hour by itself! I left the glass in the access holes so that when I’m sanding and shaping the topside hole perimeters, the glass will serve as a “catch” to keep all the foam bits & dust from getting into the sump tanks.
After cleaning up the layup and trimming the overhanging edge glass, I then stuck the sump top back in place. I’m very pleased with the fit and all indications convey that it mates securely at every contact point along the top of each sump wall.
There is a slight unevenness to the top since the weight on the right side pushed the aft side of the right access hole down just a bit more than the left, maybe 1/8″. But with a bit of judicious sanding and when the top ply of Kevlar and BID are glassed into place, I think it will be barely noticeable, if at all. It certainly doesn’t have an operational impact on the sump.
19 June 2017 — Today I 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 by the end of the day, 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.
20 June 2017 — For clarification, the glassing of the fuel sump top is final, but I have yet to flox/glass it in place on the sump tanks assembly . . .
So, as I mentioned last night, I let this layup cure to around 80% and then placed it on the sump assembly in the fuselage, where I then weighed down the edges (again) and cooked it to perfection with heat lamps! Before I actually put it back onto the sump assembly though, I did pull the peel ply (while it was EZ!) and knife trimmed all the edges. I also removed the peel ply intersection ridges and drilled out the 7 screw holes on each access hole perimeter flange.
The usual temp that the backseat area gets to in this configuration is around 120° F, so I figured I would let this cook for about 4 hours. I went upstairs and spent a good hour migrating my blog posts over into the build log pages, and then went for a quest for some 8-32 screws –which I bought at my local village hardware store– and some cork-rubber gasket material, which I picked up at a local auto parts store.
I chose cork-rubber gasket material since the sump access port perimeter surfaces that I’ll be using the gasket on is not perfectly even nor totally smooth. Cork is the most forgiving of the affordable gasket materials, and from all accounts, once married up with the venerable Permatex #2, it’s virtually leak proof.
Upon returning home I got everything prepped and ready to start back in on the sump build, while the sump top itself had post-cured for right at 5 hours. Again, I had pulled all the peel ply and knife trimmed it before I cooked it, so this time around I was just checking the layup over for quality (there were some minor delams where I folded the glass around the edges of the foam which I simply cut away) and giving the edges a nice final sanding with the hardboard [FYI/FYA – Pulling peel ply after a part has been post cured is NOT fun!].
One of my first tasks out of the gate today was I needed to trim down the outside edges of each sump access hole nutplate ring. Since the glass on the bottom side around each hole went just a tad wonky on me, I needed to make the footprint for each nutplate ring as narrow as possible. I trimmed up each ring with the Dremel tool and a cutoff disk, and then finished the edges with a couple rounds of filing.
I then started an iterative process of trimming away half circles on the front sump wall flange to allow clearance for the nutplate rings once mounted in place on the underside of the sump top.
I was also a bit concerned with the sheer wonkiness of the right access hole glass, so I checked it out first with the top cover plate in place to ensure it didn’t need any special attention. Actually, the only special attention I had to give anything was that I had to curve the top cover plates a bit for a better mounting contour. Now, even though these cover plates are ONLY 1/16″ 2024 aluminum, they are NOT EZ to bend!
Well, I got the top plates bent well enough, and then test mounted them both into place with a full compliment of 8-32 screws into their respective nutplate rings on the opposite/interior side of the sump top.
After a half dozen rounds of trimming the sump front wall mounting flange, I was able to slide the sump top into its final mounting position with clearance for both access holes’ internal nutplate rings.
With the sump top ready to be mounted, I decided I wanted to try it out to ensure there just wasn’t any unforeseen problems I was missing. Plus, I was curious how well it would work. The picture below may seem like some crazy guy taking a really weird pic, but I wanted to show that both GIB left & right armrests were installed, plus the sump top was in place. This is the first time that I’ve sat in my plane when it actually felt like a real seat in it!
How does the thigh support feel? AWESOME! I haven’t sat in too many Long-EZs, but whether or not any builder is using a thigh support sump, they should definitely go for the thigh support. It felt so good I almost fell asleep just sitting there pondering my build!
The next step was to get the access holes’ nutplate rings floxed to the hole flanges on the internal side of the sump top. I whipped up some flox using E-Z Poxy and very carefully floxed the nutplate rings in place. I had planned on using the access hole cover plates to help ensure the angle of the screws were correct, but right about when I was getting ready to put the screws into the flange on the left side, I heard a huge crash upstairs. Something had definitely fallen. Well, my fingers were all covered with flox so I quickly put the screws in and tightened down the nutplate ring, removing all the excess flox that was oozing out as I tightened the screws.
Before I did the right side, I went upstairs to investigate the potential calamity . . . well, apparently Jack Wilhelmson’s canopy latch kit didn’t like my tall surround sound speaker and took it out. I uprighted the speaker and separated the two, and then got back down stairs to finish floxing on the right access cover nutplate ring. It was then that I noticed in the distraction of the loud bang of something falling down upstairs, that I had forgotten to place the access hole cover in place on the left side. Oh well, I’ll mount it when I do the screw swap outs to ensure the screws don’t get floxed into place.
I plan on letting the floxed nutplate rings cure for 2, if not 3 days, to ensure the flox really holds these guys in place.
21 June 2017 — As the sump access ports’ floxed nutplate rings are still curing on the sump top, I figured it was time to get some other tasks completed in and around the GIB area. I started off in the sump itself by drilling a 1/4″ hole into the bed of micro in the left sump tank to mount a “roll-it-yourself” 4-40 countersunk stainless steel screw as a clickbond. This 4-40 screw post doesn’t have to be super strong and in many ways will serve as a guide to ensure proper Holley Hydramat positioning in the sump tank… if there actually is such a thing! I say this because with the hard mounted tubing, I don’t see the Hydramat straying off anywhere other than where it is supposed to be. But again, a 4-40 screw post will serve as a nice guide during the initial install and subsequent replacement of the Hydramats.
I then set the 4-40 countersunk stainless steel screw in place. It looked like a nice fit!
On the right side I couldn’t place the screw post (aka “clickbond”) near the center sump wall since the fuel line tubing going to the left sump is right over where it would need to go. I thought a few minutes about not putting in a screw post on the right side, but then figured if I put it near the drain valve, I doubt seriously if it’s going to block any water draining into that area.
However, since I wasn’t drilling down into the micro-contoured floor, the drain corner didn’t provide the depth I had counted on for the 3/4″ long screw. Standing on the bottom tank floor alone, it was just too tall. I punted and used a regular 1/2″ 4-40 stainless steel screw, but covered it with an upside down Tinnerman washer to help stabilize it once it was awash with wet flox and subsequently cured –along with a couple plies of BID over top of it.
To get the normal screw to stand upright in space I simple taped it to a line, then clamped the line to a popsicle stick hanging off the top of the longeron like a diving board. I then 5-min glue the bottom of the screw, slightly adjusted the line where I wanted the screw and Voila! … the screw ended up exactly where I wanted it!
I then floxed in the 2 Holley Hydramat 4-40 corner screw posts, covered each one with some wet BID, and then peel plied them.
23 June 2017 — Today I cleaned up the layups of the 2 Holley Hydramat screw posts that I floxed and glassed into the right front corner of each sump tank. Below is the right sump screw post and fuel drain valve shown in place with the Holley Hydramat installed.
I then sanded virtually every surface on the sump, shop vacuumed it all and cleaned it up. I then prepped for the final mounting of the sump top by taping all the openings that I didn’t want any errant flox or epoxy getting into.
I then removed the access cover tops and sanded both sides of the sump top, in whatever surfaces were subject to getting glassed to the lower sump base. I did have to Dremel around the forward floxed edge of each access hole nutplate ring to ensure that it was smooth, yet a bit textured for yet another round of flox.
I then spent 6+ hours total floxing and glassing the sump top to the sump base. Why did it take so long? Well, one reason was I underestimated –a couple of times– just how much flox was required on all the parts of the base to get this sucker glassed in place!
After I finished cleaning up at the end of this unannounced monster layup, I took a shower and went out to grab a celebratory beer & burger. When I returned an hour or so later, while checking the layup, I went ahead and removed all the tape that was around each hole protecting the nutplates from errant epoxy, flox, etc. I also trimmed back the BID and peel ply about 1/8″ further towards the front sump wall away from the front edge of each hole to provide a nice ridge-free setting for each access hole cover plate and gasket.
24 June 2017 — This morning I started out by spending about an hour pulling all the peel ply and cleaning up the layups on last night’s floxed & glassed sump top. After I got the peel ply pulled and the peel ply edge residue removed, I then put the weights back in place and put the whole thing under heat lamps.
I went out for a bit and by the time I got back it had been 4 hours, which is the minimum amount of time I wanted to post cure the sump top attach layups to the sump base. By the time I gradually reduced the heat and actually got all the heat lamps turned off, the post cure was right at about 5 hours.
I then cut out 2 gaskets out of my cork-rubber gasket stock for the two sump access holes.
I then drilled counter sinks into the 7 holes on each cover plate and then installed the cover plates for the time being to keep dust, dirt and anything else out of the sump tanks. I took the shot below after I had just finished mounting the left sump tank access cover, but while the countersinks on the right sump tank are still visible with no screws.
26 June 2017 — Today I set my sights on getting the front fuel sump “Leading Edge” 3/8″ Nylaflow tubing installed. This tubing will serve as a hidden electrical conduit to get the left GIB armrest comm wires over to the right side and up to the intercom, and also the left side Atkinson fuel site gauge LED wires over to the small wire bundle on the right side as well.
I started off by taping the 3/8″ Nylaflow tubing in place, then gluing it place with multiple dabs of 5-min glue.
After the 5 min glue cured, I then whipped up some micro and micro’d the gaps on the top and bottom side of the Nylaflow conduit.
I then laid up 1 ply of BID over the fuel sump “LE” 3/8″ Nylaflow electrical wire conduit.
Jumping ahead a few hours later, I then pulled the peel ply and cleaned up the layup. I think I will need to follow up with about 3 x 6″ layups (left, middle, right) to finish off this task.
I also cut up some urethane foam blocks and shaped them into a hexagonal pyramid shape with a flat top for the sump’s low fuel sensor covers. I was going to do something more fun, like some big hex bolt looking covers, but I realized that if it had a flat surface on it than the GIB might mistake it for the sump top when climbing in and put all their weight on it . . . not good! Thus, I needed the covers to slant so while climbing in, any passenger who tried to use it as a step point would quickly realize it’s not as their foot slid off of it. Better the GIB have a bit of a surprise stepping-in wise than snap off one of those sump low fuel level sensors . . . especially with a worst-case scenario of causing a fuel leak into the cockpit!
Once I got the foam shape down (again, not perfect . . . oh, well — let’s stuff them where they work fine but no one can see them!) I taped the foam forms to the work table. I only used a round of duct tape on these forms, so no clear packing tape. I then laid up 2 plies of BID over each form and left them alone to cure.
After cure, I popped them off –nice & EZ with these types of forms– and gave them a quick trim (below).
I then took my original outline that I made up a few hours ago, added a 1/4″ to the perimeter and then marked up the sump low fuel sensor covers for trimming. It’s way too late to trim tonight with the noise, so I’ll trim and sand them tomorrow.
27 June 2017 — Today I started out by cutting a small wedge of Kevlar to place over and around the sump’s front corner edge Nylaflow conduit. I wanted to make sure that when the GIB steps into & out of the back seat that the Nylaflow conduit doesn’t get damaged.
I then cut the 2nd ply of BID to get laid up over the first ply of sump LE BID and the new piece of Kevlar. I then wetted out the BID in place on the sump & then peel plied it after the layup was complete.
I had to make a Harbor Freight run, so after a number of hours I pulled the peel ply and cleaned up the sump front edge Nylaflow covering layup. This is what the GIB back seat area is looking like these days. With that last layup I’m done with fiber-glassing on the thigh support fuel sump, unless something new pops up of course.
I was also finally able to get the sump low fuel level sensor wires soldered tonight. Since these are very low current sensors I’m using 24 AWG wiring for the leads that will traverse through the front sump wall Nylaflow conduits up to the Triparagon, where they’ll connect to power, ground and EFIS data input.
Here is the initial splice of the red wire of the left sensor.
And immediately after I soldered the wires together.
Here’s the blue wire soldered . . .
And all the sensor wires cut shorter and solder-spliced in this pic.
I also did the same process for the right sump tank’s low fuel level sensor. Tomorrow I’ll heat shrink all the splices to finish up this task.
I also trimmed the edges of the sump low fuel level sensor protective covers as well, but failed to get a pic of them after they were trimmed up.
28 June 2017 — Today I decided to do something more a little my speed: heat shrink! I finally got around to cutting the heat shrink tubing for the left & right sump tanks low fuel level sensor wires and heat shrunk them in place.
9 August 2017 — Today I spent a bit of time sanding down and cleaning the fuel sump low fuel sensor covers.
Here’s the exterior side of these things . . . After sanding, I then gave them a good Simple Green wash and dried them off.
I then taped up the interior edge of both sensor covers and then shot them with a couple quick, light layers of black paint. I would have preferred to use matt paint, but I only had gloss on hand so they’re a bit fancier than I had intended.
A bit later I took a quick opportunity to apply a couple of coats of gray primer onto both thigh support fuel sump low fuel sensor covers. Since I’ll have a pair of LEDs poking out the bottom of each of these covers, I wanted to get them painted so as to not have to worry as much about taping off those LEDs, which again will be on the bottom side, when I paint the rest of the back seat area.
10 August 2017 — Today I took my fuel sump low fuel level sensor covers outside and painted them with the Rustoleum granite paint that I will be using for the interior cabin paint.
I then determined the size of the phenolic LED light mounting reinforcement plates, cut them and then 5-min glued them into place (after I removed the paint and sanded the glass where they were mounted inside the covers).
I then determined where the 2 LED holes would be situated, then drilled the holes. I tested out the angle of the LED light beams, so when I drilled the holes I made them a bit more horizontal in comparison to the aircraft waterline.
With the LED mounting holes ready, I then prepped the LED lights for mounting by soldering the red & white LEDs and wires, including a 470 Ohm resistor on the shared ground wired.
I then added heat shrink to secure & protect the solder joints.
Although the pic below looks like you’re looking down into a fiery volcano, I included this representative shot of the red LED test lighting.
Here’s the white LED test. Again, the light showing up in these pics is more drastic, contrasting and harsh than what is really viewed in person.
Here are another couple shots of the sump low fuel sensor cover LED floor lights from the front, facing the camera (which I shot at an angle so they wouldn’t “blind” the camera).
Again, this is a representative view of the red & white LED lights glued in place into the right sump low fuel sensor cover. The left looks pretty much the same of course.
[NOTE: The electrical portion from above is posted in Chapter 22 – Electronics]
13 August 2017 — Today I checked the mail and found the Permatex 80725 Plastic Pipe Sealant that I ordered was delivered quite ahead of its stated delivery date. Up until last week I was simply considering using pipe tape to install the ELS-950 sump low fuel level sensors, but after further thought I decided to order the sensor manufacturer’s recommended Permatex 80725 to better ensure no leaks. To be clear, as a function of the low fuel level sensors they must be situated below the high fuel mark, making the ELS-950 sensors installation seals critical to having no fuel leaks.
With my preparing to install the sump low fuel level sensors, I needed to create wire labels for both the sensor wires and the GIB LED floor lighting wires that are located in the sensor covers. Besides just wanting to keep my wires identified, in this situation it’s even more vital since all these wires are hidden away for the first 12-18″ and ascertaining what wires go to what would be much more difficult without wire IDs.
With all the obvious effort I’ve done on my electrical system, this little ditty here shows how extensive the task is: As I was listing out my wire labels to print I realized that I didn’t have enough consolidated information on exactly what component power wires connected to my power busses at which tabs. With the addition of a few extra unexpected electrical components over the past 6 months –including these low fuel sensors– it’s really too easy to lose sight of exactly what power wires feed from what buss, and exactly what tab a specific wire may get connected to.
Thus, yes, another unintended and unexpected task reared its head… I determined that my sheet of notebook paper with the Main, Endurance and Battery power buss connections listed on it just wasn’t enough. I needed it in electronic format as a worksheet in my electrical system spreadsheet, so I made that happen. Then I spent a few hours inventorying every instance and every wire that connects to a power buss, including each buss’s threaded feed stud.
Besides the information listed on my tattered notebook sheet, I did an accounting for the already labeled tabs on the physical ATC fuse busses. I then went through literally every wiring diagram to account for every listed power buss connection in the diagrams. I then went through my components list to ensure that the power feed for every electrical component going into the plane was accounted for. Through all this I found some discrepancies in the required fuse sizes. Finally, with a complete accounting of all my buss power connections I was able to reorganize some connections on the respective buss tabs.
I then printed out my labels for my sump low fuel level sensors.
14 August 2017 — Today I tested out one of my ELS-950 sump low fuel level sensors. Here’s a video showing how it works.
With my sensor function test good to go, I then applied a light ring of Permatex 80725 around the threads of each sensor and then installed them into their respective ports on the vertical face of the thigh support fuel sump.
Here’s a wider angle shot showing where the sensors are situated on the front of the sump front wall.
I then taped up the sensor wires to keep them out of the way for when the covers are installed.
I then added a spot of tape to the aft ring of each sensor cover and mocked them up in place. Looks like they’ll fit just fine.
I then spent a fair bit of time labeling all the left and right sump low fuel level sensors’ wires.
I combined the 2 sensor ground leads into 1 wire by solder splicing them together. Here they’re prepped to be soldered.
And here the ground wires are solder spliced with a lead leading to the Triparagon.
15 August 2017 — Today I installed the left sensor cover in place using 5 min glue on 2 adjoining sides and silicone RTV on the other 4 (It’s hex shaped). I then used my main battery to keep it in place while it cured.
A bit later I then 5 min glued & RTV’d the right sensor cover in place. To be clear, I tested the LED lights in each sensor cover before securing them in place.