Project Update

Hey Guys,

As I previously mentioned, the bottom cowling is pretty much installed and squared away… with the very final installation occurring when the top cowling is installed.

Also as I noted before, over the last few weeks I have been focusing on the Hell Hole area to create a functional and usable hatch as well as install the belly RAM air scoop.  For the most part, both of these tasks are completed.  I do have to add a couple screw hardpoints to secure the RAM air scoop/hell hole hatch cover and create a bell mouth inlet at the front of the scoop (later) –but beyond these tasks, both the hell hole hatch cover and RAM air scoop are complete.

While the fuselage is inverted I’ll also press forward to knock out a number of other things, including strake-to-bottom wing intersection finishing and main gear leg-to-fuselage interface. 

I expect this bird to be inverted for another week or two before it gets flipped back upright to close out the strakes with the top skin install.

After the top strakes it will be on to the winglet/rudder install (Chapter 20).  Then engine and top cowling install, finish and prime/paint.


Chapter 13/19/24 – Prepping for finishing

I started out the day adding yet another ply of BID to what was the delam on the outboard bottom side of the right wing.  The delam is now gone, but I still have a bit of a depression from all the foam that was removed along with the micro and glass when it delaminated.

I had peel plied the layup and thought I took a pic of it, but only had this shot much later in the evening when I removed the peel ply.  Still, I’ll be adding at least one more ply of BID to this repaired delam to get the divot to an acceptably filled in level as compared to the surrounding wing surface.

I then glassed the nose wheel well front wall foam extensions (about 1/4″ deep) with 2-ply BID layups over dry micro fillets on the bottom and inboard edges.  You may also note the micro I filled in on areas down the nose gear strut channel.

Tomorrow I plan on trimming the overhanging glass and then creating small flox edges front and aft as I lay up a ply of BID on the top of each of these foam extensions.

Moving on.

Part of my laundry list of tasks to complete before the bird gets flipped back upright was the front face of the F28 bulkhead.  If you recall, I poured this foam when the fuselage was vertical while I was flipping it inverted.

This task is actually a recent add to my to-do list, when I realized that it would save a lot of cleanup from all the foam and dust from going into the airplane if I simply did all the work now.  Thus, I first took a standard wood saw and cut off the initial majority of the foam.

I then took about 20 minutes to shape and sand the foam flush on the face of F28 (pic #1).

I then traced out a quick cardboard template to allow me to cut the single ply of BID I then laid up on the face of F28, after applying micro to the foam of course.

I then wetted out the BID (pic #1).

And then peel plied it (pic #2).

I then spent a good hour cleaning up and organizing the shop and clearing off a bunch of stuff from the strakes and wings in prep to sand the plane’s bottom glass surfaces for micro.

I then sanded a good bit of the bottom left fuselage in prep for micro finishing.  But it was late so I called it a night before finishing the other side.

Chapter 19/22/24 – Hell hole antics

I started off today adding another 2 plies of BID to the right wing bottom outboard delam repair.  Yes, the crater is still a bit more depressed than I want (or the plans call for) so I decided to slowly add to the thickness and re-evaluate.  I laid up one full ply inside the depression and then another “half”-sized ply towards the trailing edge.  I then peel plied the layup.

I really want to get all things on the bottom of the plane completed and not have to mess with them once the plane is back upright.  Part of this is the interior paint (first) on the landing brake.  I have some ideas on what I want to do, but first I had to get the landing brake off the plane….

Wow, talk about sins of the past coming back to bite us.  I guess I didn’t ever think this landing brake would need to be removed, so it was a bear getting it off… about an hour of pain and sweat!

Obviously I finally got it removed.  I sanded it to rough up the surface then gave it a good wash with Simple Green.  I then used some Metal Glaze to fill a number of small holes in the surface of the landing brake (pic #1).

I then measured and marked the perimeter border of the landing brake (pic #2).

I then taped off the perimeter border with painter’s tape.

I hit the interior area with a few coats of primer.

In between the coats of primer on the landing brake, I constructed the final oil heat line hose to connect the oil heat pump feed from the firewall fitting, that is itself connected on the other side to the engine oil sump.

Moreover, to secure this newly added hose I floxed and glassed a clickbond on the bottom of the gear strut to then mount an Adel clamp.  Here it is quite a few hours later after the clickbond glass had cured.

I then spent a couple of hours installing the fuel tank probe control heads into the hell hole. I started by finalizing the wiring configuration and labeling, then soldering the wires into the hell hole.

After connecting and wiring up the fuel tank probe control heads, I then physically mounted them into the hell hole on their respective mounting pads.

It was getting late, but I wanted to get a couple more tasks knocked out.

First I cut and 5-min glued a pair of foam tabs onto the front wall of the nose wheel well. These tabs, once secured via glass, will provide a hard stop for the front edge of the gear doors.  Not the current front edge mind you, but in fact will allow me to trim off that first tab jutting out very conspicuously… reducing the number of “steps” from 3 to 2.  I think this will drastically improve the appearance of these gear doors.

Finally, I spent a few minutes sanding and filing the inside of the micro’d hole on the aft side of the bottom centerline video camera mount housing.  I then cut a slot on the forward bottom (as situated) to run the camera and cable up into the housing.  After a few test fit iterations, with subsequent rounds of sanding, I was able to get the video camera slid up into the mount housing.  Again, I’ll secure both camera and the cable inside the nose wheel well once I hook the system up and position the camera view correctly.

I expect to have maybe one more day of working these prerequisite bottom-fuselage tasks before the priority will shift to sanding/micro’ing/finishing the bottom surfaces of the plane and working these tasks in-between the micro applications during the curing times.

Chapter 13/19 – 2 huge tasks complete

Today I got 2 really big tasks knocked out in my quest to get the bottom of the plane finished to allow me to flip it back upright.

First was a delam on the outboard bottom trailing edge area of the right wing that I discovered when I pulled the wings out to cut the aileron pockets.  I have been pondering on exactly how to fix it, but since I have not dealt with a delam this big before I knew I would need to dig into the plans to help guide me on the how-to.

And I’m glad I did.  I discovered that any delam larger than a couple of inches in diameter need much more of repair than just shooting raw epoxy under it and weighing it down. According to plans Chapter 3 the glass needs to be removed, the edges feathered back, and new glass laid up in the same bias as the original glass, with an overlapping ply of BID.

Yes, I had to then go to Chapter 19 to double check the direction that the plies of UNI were laid up on the wing.  About 30° each ply as per below.

I then ID’d the edges of my delam as best possible, and marked the offending area for removal.

Then I grabbed my trusty Fein saw, took a deep breath, and then cut a large chunk out of my wing skin.

I then laid up the 1st and 2nd ply of UNI in the approximate orientation as the Chapter 19 diagrams shows, overlapping out onto the feathered glass a minimum of an inch (yes, the plans show 2″… I made a call here).  I then covered the UNI plies with a ply of BID that went out beyond the UNI a minimum of a half inch.

Planned anyway. My BID went a little wide, and not so tall, but it stilled covered the UNI and all looked good.

I then peel plied the layup.

Late in the evening, with the layup fairly cured, I then marked up the peel ply with subsequent plies of BID required to help back fill this large divot I had just created on my wing.

You see, it doesn’t seem like removing the top layer of 2 plies of UNI should make that much of crater in the wing, but when it takes all the interfacing top surface of foam that is secured to the underside of the skin with micro, that’s a good 1/8″ of material gone.  I suspect I’ll need even maybe another round or two more plies of glass to fill in this area.

Huge task #2 was getting my nose gear doors working so that when they open up as the gear is lowered, both doors are vertical and parallel to each other.  In their current state for the past 5+ years, this has not been the case.

A serendipitous discussion with my Long-EZ building buddy Brian Ashton, and a few pics and measurements he texted me, was just the trick I needed to fix this long-nagging issue. I explain what I did and discuss it in a video I made here:

With these tasks out of the way, I’m getting much closer to sanding and micro-finishing the bottom surface of the bird in prep for paint and flipping it back upright to continue on with my topside build tasks.

Chapter 22/23/24 – NACA scoop glassed

I started out today by cleaning up and trimming the engine NACA scoop connector that is the interface between the NACA’s aft fitting and the SCAT tubing that carries the air into the engine compartment.

I then test fitted it into the 1.25″ SCAT tubing… so far so good.

And then test fit it on the NACA aft fitting.

It’s a go!

With that piece of the puzzle out of the way, it was time to proceed with getting the SCAT tubing ran from the aft fitting on the NACA scoop into the engine compartment, via the firewall bridge.  The idea here is simple: drill a 1-3/8″ angled hole through the flange on the aft bottom side of the firewall to run the SCAT tubing.  My goal was to get the hole as close to the inside edge of the firewall bridge as possible, to allow as much clearance as possible between SCAT tubing and the RAM air can.

I then drilled the 1-3/8″ hole using a step bit.  It came out nice.

After cleaning up the edges of the hole I then test plumbed my SCAT tubing… again, so far so good.

A shot of the SCAT tubing entering the firewall bridge.

I then tested out connecting the SCAT tubing to the NACA scoop aft fitting… it’s tight, but doable!  I’m really glad that I didn’t go with the 1.5″ tubing since I don’t think it would have worked.  There’s just not enough space in these tight quarters for any larger SCAT tubing.

I then re-installed the RAM air can as the final checkout to ensure there was clearance between it and the NACA scoop’s SCAT tubing.  There’s just enough clearance for both to coexist and not impact the functioning of the other…

With the physical connections tested out, and the NACA air routing plan a go, I proceeded to glass the inside of the NACA scoop with a ply of BID, in 2 pieces: one on top and one on bottom, overlapping a bit on the sides.

While the NACA scoop glass cured, I then used my ClampTite tool to secure the SCAT tube connector into the forward end of the SCAT tubing.  Note that I secured the wire band of the SCAT tubing under the wire clamp.

Here’s the final position of the NACA scoop’s interfacing SCAT tube connector, residing in its home in the firewall bridge.

Later, once I get all the firewall components in their final configuration, I’ll make up a “Y” fitting that splits the NACA scoop air into 2 paths via 1″ SCAT tubes to respectively cool the mechanical engine-driven fuel pump and the PMAG electronic ignition.

I had poured foam into the fuselage bottom centerline video camera housing earlier and finally got around to trimming & sanding it down to be even with the backside surface of the housing.

I then marked the housing for trimming.

And then trimmed off the backside edge and sanded the surface of the video camera housing.

I then drilled a 3/8″ hole on the aft side of the video camera housing and tested out its position on the bottom of the fuselage, just aft of the nose gear doors.

As I mentioned before when I used the original S-glass nose bumper nub as a mold, I didn’t need the video camera housing to be as tall/deep as the bumper was… here the profile is just under 5/8″.

And a shot of how much the video camera housing will protrude in flight.

I had already drilled a 3/8″ hole [the size of the camera lens, since I have to route all the cabling in reverse due to the pre-wired connectors] at an angle from the bottom fuselage surface into the nose wheel well, and here I’ve also drilled a 3/8″ hole in the top right aft edge of the nose wheel cover to route the bottom CL fuselage video camera cables.

Since I don’t know the required clocked position of the camera for it to display a nice horizontal/upright shot on my EFIS, I need to wait until I get the EFIS installed and fired up to do the final mounting of the camera.  However, to secure the cable in place, but still keep flexibility in positioning/rotating it, I used pour foam in the drilled cable channel.

Here we have the bottom CL fuselage video camera cable & connectors exiting the nose wheel cover, and ready to be connected to the video camera multiplexer.

After I confirmed fit and configuration of the bottom CL fuselage video camera housing, I created small flox corners around the perimeter of the backside and then glassed it with a ply of BID.  I then peel plied the layup.

This shot is clearly a number of hours later after I pulled the peel ply and trimmed the layup.

I then slathered in some micro around the edges of the video camera mounting hole for a nice appearance and transition.

After a good bit of video camera shenanigans, I then got back onto the mostly cured NACA scoop layup.  I had laid up the glass going into the aft fitting tube to keep the glass transition as smooth as possible.  Here I’ve just trimmed the glass at the aft edge of the aft fitting.

I then test fitted the trimmed, sanded and cleaned up NACA scoop as I set the RAM air scoop/hell hole hatch cover back in place.

Here’s a longer shot of the NACA scoop on the RAM air scoop aft structure.

And a profile shot of the NACA scoop on the bottom aft side of the RAM air scoop structure.

I had to do some minor trimming and sanding to make the interfaces nice and tight again, but after some minor fiddling the fit was good.

I then added some more micro around the top (as positioned in the pic) of the NACA scoop aft fitting and then glassed a ply of BID in over the bare foam.

And with the NACA scoop pretty much complete and the interface fits good, I left this layup to cure and called it a night.


Chapter 22/23/24 – Engine NACA scoop

I started out today by sanding and shaping the micro fillet I inlayed around about half of the junction between the aft RAM air segment and the front face of the firewall. I’ll do one final tweak, but I’d say this gets me very close to where I need to be… at least 80-90%.

I then got to work on the RAM air scoop aft structure-mounted NACA scoop that will supply cooling air to both the PMAG electronic ignition and the engine driven fuel pump. The template I used was right out of a CSA article on NACA/flush-mounted scoops.

Now, to be clear this is a bit of an experiment on yes, an experimental aircraft.  I say this because there are 2 factors that make this a non-typical NACA scoop install… at least in my book.  I could very well be wrong of course.

First, the segment of RAM air scoop structure that this NACA is embedded into is not flat, as you can see here.

Next, and although I didn’t get a shot of it (yet).  The portion of the RAM air scoop aft structure where this NACA scoop is located is just aft of where the profile of the scoop structure starts to turn upwards to eventually blend into the bottom cowling.  Since it’s not on a straight and level segment of the bird I’ll have to monitor how it does.

To be even more clear, if this turns out to be a big fail it would take maybe 2 days to rip it out, fill the pocket with pour foam, glass over with a ply of BID and then spend a day or two painting it.  Barely any, if any, added weight in removing it.

I then got busy on the NACA fitting that will jut out of the aft side of the NACA scoop. This fitting will slide into a connector that will connect the NACA to a 1.25″ diameter SCAT tube that carries the air into the engine compartment.  I had been shooting for a 1.5″ diameter SCAT tube, but space is tight in this area, especially in the firewall bridge.

Once I got the configuration of the aft NACA fitting set (or so I thought), I secured it with tape and then poured foam around it.

Here’s a bit after I hacked off some of the pour foam. Note the blue foam in the front portion of the NACA fitting to keep pour foam out.

I then test fitted the NACA fitting position and didn’t like what I saw.  It was a bit too high and too angled down.  It was a good (better?) position most likely for air flow (that’s the whole point, right?!) but getting the RAM air scoop/hell hole hatch cover on and off was just not going to happen with the NACA fitting in this position.  I needed to lower it just a hair, and straighten/level it just a hair more (less angled) for it to work.

Here’s the final position I settled on. My intense background in armchair engineering makes me think this will get cooling air to the targets pretty darn close to what the previous position would have…. at least that’s what I choose to believe! <grin>

I micro’d the bottom portion (as situated in the pic) and laid up some BID around it to secure the NACA fitting.

I also taped up the end of a 1.25″ aluminum tube with a taped up toilet paper roll sticking out of the end to make my male/female connector to connect to both the NACA fitting above and into 1.25″ diameter SCAT tubing.  I then peel plied this 3-ply BID layup.

My last task for the evening was to use the original somewhat-aerodynamic S-glass grazing nub —in lieu of a hockey puck… this was before Marco machined me a very aerodynamic/cool bumper from a hockey puck— from Feather Light as a mold for my bottom center line-mounted, aft-facing video camera. I didn’t need quite the height for mounting the camera and I definitely didn’t need a heavy, solid S-glass piece to mount it into… but I liked the shape so I just glassed a few plies of scrap BID over it.

I’m guessing in all my machinations tonight I forgot to grab a layup pic of the video camera mount housing, but a few hours later I pulled the layup from the mold and cleaned it up. Here it is.

Tomorrow I’ll continue to work on the NACA scoop and all the tasks on the bottom of the bird so I can get it finished for paint and then flipped back upright post haste.


Chapter 23/24 – RAM scoop CAMLOCs

I started out fairly early this morning to get the last set of 2 pairs of CAMLOCs installed on the belly of the fuselage to secure the RAM air scoop.  Unlike the aft flange-mounted pair of CAMLOCs, these 2 are much more challenging in that when I cut into the added foam layer of the aft bottom fuselage, the depth wasn’t far enough to allow the CAMLOCs to compress far enough and operate as designed.

Last night, after pondering on it for a bit, I decided to press forward and simply cut further and deeper into the original bottom skin of the fuselage —directly beneath the GIB seat pan— and get my needed 1/8″-3/16″ added depth there.

In the pic below you can see I did exactly this on the right side (bottom of pic) . . .

I then tested out a -2 CAMLOC installed in one of the threaded-CAMLOC receptacle phenolic blocks.  It fits! . . . whew!

I then did the other side… here I show some of the mess involved in doing so.

I then taped up and floxed the threaded-CAMLOC receptacle phenolic blocks into the bottom of each hole, so that technically the top of each CAMLOC block is floxed directly to the underside of the GIB seat pan glass.

I then laid in 2 plies of BID with a center hole cut out for the CAMLOC.  I then inserted, tucked, jammed the glass up under the lip around the edges of each square cutout.  I then mixed up drier micro and pressed the glass fully into the recesses along the edges.

Here’s the results.  Not bad. Also not pretty.  But it will definitely work!

And a wider angle shot so you can get your bearings on where all this is going on.

I then ran a plumb down the aft centerline of the RAM air structure and bottom cowling to ID the spot for the bottom cowling BDC CAMLOC.

I then installed what should be the last CAMLOC I install while the bird is flipped inverted… the next round of CAMLOC installs should come while I’m installing the upper cowling.

I then remounted the bottom cowling and tested out my BDC CAMLOC install… worked a treat!

And again, thankfully nether RAM air scoop/hell hole hatch cover bottom center screw nor bottom cowling bottom center CAMLOC distorted the RAM air scoop aft structure in any way.

I grabbed a shot here showing the latest additions to the RAM air scoop/hell hole hatch cover: the right side CAMLOC and BDC screw.

And a couple shots of the new RAM air scoop flange-mounted CAMLOCs.  The depth on these threaded-CAMLOC receptacle phenolic blocks into the fuselage belly was more than  adequate since I ended up needing a -8 CAMLOC stud (whoa!)… which I only currently have 1 on hand.  I’ll order a couple more next time I submit an order to ACS or Skybolt.

It was getting late in the evening and my last couple of tasks were minor ones, but ones I wanted to cross off my list.

First was laying up a couple plies of BID around the aft opening of the forward RAM air scoop… the side attached to the hell hole hatch cover.  This opening got beat up fairly badly when I extracted the aft RAM air scoop piece —with freshly glassed flange— from this section.

As you can see, I then peel plied this layup.

Next, I removed the RAM air can and added some dry micro to the fillet on the inside of the RAM air scoop aft segment, at the junction with the forward firewall face. I”ll note that this will be an iterative process, so this is just another positive step in the right direction. I still need to clean up this application of micro and then probably add at least one more round.

I then let the micro and layup cure overnight.

Chapter 23/24 – Firewall bridge flanges

Today was one of those tedious work days where it seemed like there was a ton of work done without a lot of results to show for it.

I started by pulling the RAM air scoop/hell hole hatch cover from the bottom fuselage.  I had to carefully rock it back and forth, up and down to get it to break free from the glassed flange that was gripping the mold-release packing tape on the inside surface of the aft RAM air scoop/hell hole hatch cover.

The flange turned out fine, and here’s another shot of it.

And a somewhat fuzzy shot looking through the aft end of the firewall bridge.

I then pulled peel ply, trimmed and cleaned up this forward flange on the firewall bridge.

I then spent a bit of time aligning and prepping stuff, that finally led to my installing a K1000-3 nutplate as the final aft secure point for the RAM air scoop/hell hole hatch cover.

Here’s an exterior shot of the latest installed screw point to secure the RAM air scoop/hell hole hatch cover.  Thankfully this screw point install didn’t mess up the nice flow between the forward RAM air scoop and the shape of the firewall bridge.

I then spent a good half hour pulling peel ply and cleaning up the RAM air scoop structure aft end: the bottom cowling.  Here’s a couple shots of the cleaned up pocket that now exists on the front edge of the bottom cowling.

I then set the cowling back in place and added some weights to each side of the new protrusion to press the cowling lip into better alignment with the firewall bridge.

After taping up the bottom lip of the pocket on the front of the bottom cowling –as a mold release– I then laid up a 2-ply lip and 3 more plies in the center for a 5-ply CAMLOC/Skybolt receptacle mounting flange… yes, it’s a bit difficult to tell since the colors blend, but the layup is down in there.  I also peel plied the layup.

One last shot of the glassed aft flange (AKA bottom cowl CAMLOC flange) on the firewall bridge.

I then left this layup to cure overnight.

Chapter 23/24 – Firewall bridge

Today I started out by spending well over 30 minutes pulling the peel ply and cleaning up the layup on the RAM air scoop aft structure.

I then razor knifed the seam between the center segment of the RAM air scoop aft structure, what I’m calling the “firewall bridge” and the front edge of the bottom cowling. The cut wasn’t perfect and I’ll have to clean it up a tad during the finishing stage.

I then removed all the CAMLOCs from the bottom cowling and separated it from the fuselage/RAM air scoop aft structure.

And voila! Section #1 separated.

I then did the same thing at the forward side of the RAM air scoop aft structure firewall bridge by razor cutting the seam.

I then unscrewed and removed the RAM air scoop/hell hole hatch cover from the fuselage. As you can see I was left with just the permanently attached RAM air scoop aft structure firewall bridge.

A shot of the firewall bridge from the front looking aft.

I then started cleaning out all the cured pour foam from inside the firewall bridge.

I didn’t use any micro on the foam around the firewall bridge, but did lay in some peel ply, which I pulled to have a nice clean surface for glassing.

I cut and prepregged 2 plies of BID and laid it up on the inside of the RAM air scoop aft structure firewall bridge, for a total of 4 plies of BID.  Before laying up the glass I created flox fillets in the corners to ensure as much strength and rigidity as possible in the firewall bridge structure.  I then peel plied the layup.

After removing the first 2″ of foam from the aft side of the RAM air scoop/hell hole hatch cover portion of the RAM air scoop aft structure, I then took it outside and cleaned up the glass with a Dremel tool sanding drum and some sandpaper.

I then laid up 2 plies of BID inside of that aft area.  Since a screw will secure this portion of the RAM air scoop/hell hole hatch cover at bottom center to an upcoming flange on the forward side of the firewall bridge, I added a small 2″-wide ply of BID in the center of the layup (for 5 plies of BID total on the bottom center).

I then peel plied the layup.

I then got to work doing pretty much the same thing on the very aft side of the RAM air scoop aft structure: the bottom cowling.  I cleaned out the foam and sanded/prepped the cured glass for fresh glass.

Since nothing else will be glassed or embedded here, I went ahead and glassed the aft foam wall to create a pocket with the bottom (curved) side with 2 plies of BID (added here, so 4 plies total).  I then peel plied the layup.

I’ll note on the 2 pics above that from the camera angle you can see a sliver of the RAM air can notch I made in the bottom cowling.  Just for FYI, here’s the glassed, then foamed, RAM air can notch in the bottom cowling.

I then got to work on the last set of CAMLOCs that I’ll use to secure the RAM air scoop/hell hole hatch cover to the belly of the plane.  These are the 1/4-phenolic block-mounted threaded Skybolt CAMLOC receptacles that have proven phenomenal on this build.

I had previously drilled 0.150″ diameter holes (one each side) through the RAM air scoop mounting flange into the bottom fuselage skin (just enough to penetrate the skin) to mark the positions of the CAMLOCs on both the flange and the aircraft belly.

I now centered the phenolic CAMLOC blocks on these holes and marked the perimeter of the respective blocks.

I then used the Fein saw to cut the outer skin, cleaned and vacuumed out the foam and debris, and then test fitted the phenolic CAMLOC blocks . . .

At which point I realized I had a big issue to contend with . . . you see, the bottom of these holes weren’t deep enough for the CAMLOCs to compress as they should in securing the RAM air scoop flange.

In fact, the CAMLOC in the left foreground of the pic below is a -2 stud, the shortest available and it is still too long, sitting too high to work.

Clearly I needed to ponder my predicament and make both a decision and plan for a way forward.  I decided to sleep on it and work the problem tomorrow.

I moved on to my last task of the evening.  Laying up a 3 ply flange on the forward side, and attached to, the internal surface of the firewall bridge.  I taped up the inside of the aft edge of the RAM air scoop (all the previous layups were cured, BTW) as a mold release before laying up the 3-ply flange inside the firewall bridge, overlapping into/onto the forward RAM air scoop structure.

Moreover, to add more material to secure a K1000-3 nutplate, I added a 2″ wide 2-ply pad of BID to the bottom center (remember, inverted here, so top in this pic) of the layup.  I then peel plied the layup and let it cure.

Tomorrow I’ll continue to work the interfaces of the RAM air scoop aft structure and getting those darn CAMLOC blocks installed.


Chapter 24 – RAM air scoop aft structure

I started out today by pulling the peel ply and inspecting the 1-ply BID layup on the bottom surface of the lower cowling that will mainly serve to keep pour foam out of this clearance hole.

Moreover, I would say all is good but the glass at the corners lifted and separated from the cowling surface a bit.  This will be along the edge of the RAM air scoop aft structure, or swoosh, or “canoe” if you will and will need to be trimmed down.

I then test fitted the bottom cowling to check clearance between the RAM air can and this new glassed pocket.

A shot from inside the cowling.

I then placed my shop LED light in the hell hole facing out and remounted the RAM air scoop/hell hole hatch cover securely in place.  With the light shining though the LIDAR laser altimeter lenses’ holes I traced those holes on the surface of the hell hole hatch cover [Note the mounting base/flange to the RAM air scoop has been trimmed, see pics below].

I then drilled the holes with a hole saw bit and sanded them out to size in the hell hole hatch cover to allow the LIDAR laser altimeter lenses to see the world.  Note that prior to this I trimmed away the excess glass on the RAM air scoop mounting base/flange.

Another shot of all this from the side.

I then got to work on making up the 1/4″ thick phenolic inserts for the Skybolt threaded CAMLOC receptacles.  These CAMLOC receptacles will be the second set to secure the RAM air scoop base/hell hole hatch cover to the airplane belly.

I drilled holes and tapped 1/2-20 threads in the holes for the Skybolt threaded CAMLOC receptacles.

And then floxed the Skybolt threaded CAMLOC receptacles into the 1/4 thick phenolic inserts.

I then spent a bit finalizing my configuration for the RAM air scoop aft section structure. Using a taped-in-place flexible yardstick here is what the side profile will look like.

Before pouring foam though, I wanted to secure the aft inboard edge of the hell hole hatch cover as best possible.  Since the width and shape of the RAM air scoop is now known, I could proceed with installing the aft inboard K1000-3 nutplates.

Here’s the hell hole hatch cover back in place, with all the CAMLOCs and screws installed, including the 2 new aft screws.

I then constructed my pour foam dam/form out of taped cardboard.

An angled shot of the taped-cardboard pour foam dam/form for the RAM air scoop aft section structure.

I then whipped up a batch of foam and poured it in the form.

Clearly it wasn’t enough foam.

So I waited my 10 minutes as per the directions and whipped up another batch and poured it in.

Much better this time, providing cover to all the areas.  So I pulled the forms and started the slow process of trimming down the foam.

Here’s round 1 of some honest foam shaping.

And a bit more after I pulled the taped yardstick… which defines the bottom surface outline.

A bit more focusing on the symmetry of the very aft intersection with the bottom cowling.

And finally I got all the foam shaped and vacuumed, ready for glass!

I just wanted to point out that this is all the BID I have remaining out fo the 10 yards I ordered from ACS not too long ago.  I have another bunch coming in early next week. Crazy how much glass, peel ply and epoxy I’ve been burning through these past few months!

In final prep for the 2-ply BID layup I marked and cut the foam RAM air scoop aft extension structure at the hell hole hatch cover aft line and the bottom cowling forward intersection line.  I’m calling the narrow area in-between the “firewall bridge.”

I then added a dry micro fillet around the edge of the foam and filled any larger areas in the foam surface requiring it.

I then laid up the 2 plies of BID.  Since this is just a fairing, and not a structural airframe component, I used West epoxy to save my MGS as much as possible.

Here’s a shot from the aft side.  The joggle in the centerline of the bottom cowl made the very aft curve a little challenging to nail down.  I’m going to have to call in some assistance from the finishing micro to dial this in exactly before paint.

And a whole now-completed RAM air scoop structure shot.

I then peel plied the layup… again, here we have a side profile shot.

And another long view shot. Yep, I used one piece of peel ply for the entire layup.

With that, I called it a night and left this layup to cure overnight.