I didn’t do a blog post yesterday because it was all about research.  Over about 12 hours worth, including old 1980’s Sq. III videos with Dave Ronneburg and David Orr (aka Beagle) on cowlings, baffles, etc.  Ahh, if I had only watched those in year zero!

With the bottom cowling on, I grabbed a very long 1/8″ drill bit and chucked it up.  Then I drilled 3 holes in the cowlings that marked the most critical components suffering from lack of clearance between them and the lower cowling.  Those components (marked with arrows on green tape) are:

1.  The centerline carbon fiber air induction tube.
2.  The left inboard exhaust pipe 90° elbow.
3.  The left cold air intake tube (the right side is already cut).

My initial plan for the centerline carbon fiber air induction tube was simply to extend the structure of the belly RAM air scoop to end [externally] just a bit aft of the cold air induction tube [internally].

I first found and marked the centerline of the bottom of the lower cowling.

And then marked the proposed extension of the aft RAM air scoop structure, or swoosh if you will (technical term).

First I had to locate exactly where the carbon fiber air induction tube wawouls situated in relationship to the cowling… so I drilled another bigger hole, mounted the bottom cowling and took a peek.

From there I used my trusty Fein saw to cut out an oval peek hole.

I then needed to make a decision.  You see, the tightest clearance between the carbon fiber air induction tube and the bottom cowling is about 1/8″.   And that is literally for maybe 1.5″ going forward.  From there the remaining air induction tube has a decent amount of clearance.

My secondary plan, which would be way easier and much faster, was to cut a relief hole in the bottom of the cowling to then recover with CF.  Since the average thickness of the cowling is about 0.07″, then if I relocate the “floor” underneath the very aft portion of the carbon fiber air induction tube to the existing exterior surface of the bottom cowling, I could then reclaim that 0.07″ of clearance…

I know, I know!  Barely nothing.  But that would then put me at just under 0.2″ of clearance.  Plus, since I’m only using enough carbon fiber (1 ply) to cover this relief hole, then there is a bit more give than the much thicker cowling.  Essentially what I’m creating is an oval “soft spot” on the bottom of the cowling that when painted will be indistinguishable from the rest of the bottom cowling; will keep the air in; and will have a considerable bit more give if “pushed around” by the more stout carbon fiber air induction tube.

It took a few iterations to get the clearance dialed in.

Pert near final!

I took the lower cowling outside and did a fair bit of sanding on it before bringing it back inside and cleaning it up.

I then taped inside the hole with some thick duct tape.

And slathered some pour foam into the hole.

Baking some more bread!  (A side view).

About 10 minutes later, after cure, I then hacked the foam down before sanding it to match the bottom cowling surface.

I then applied clear packing tape to just the foam area.

And also a layer of peel ply that was cut the same shape and size as the foam.

I then laid up 1 ply of CF (see the horse head? Hint: it’s sideways)

I then peel plied the layup.

To be clear, if after flying for a bit I notice any significant chaffing, rubbing or contact between the CF air induction tube and the cowling, I will then employ my initial plan and take the RAM air scoop aft end all the way to nearly the end of the bottom cowling boat/shark/rudder tail to ensure the required clearance is on hand. 

As the first CF layup was curing, I then notched the left side divot that will allow just a bit more clearance for the cold air intake tube.

I then added a “propeller” to my bird.  I noted that in the propeller installation instructions it says to check the distance of the prop from the TE of the wing on each side to see if the prop is rotating in a perfect circle perpendicular to A/C centerline.

I decided to investigate the dimensions of the prop not only on how it aligned with the wing on each side forward of it, but straight out 90° from the prop hub.

That’s when I fell into yet another rabbit hole. . . (they’re everywhere on these builds!!!)

If you remember about 10 months ago, before I mounted the winglets I did a deep dive on if my wings were straight and equal to each other.  Since I hadn’t installed the winglets yet nor did I have the engine installed, I didn’t have nearly as many solid data points to refer to on just how the wings were looking.  Back then they looked great and I determined —in many different directional dimensions— that they were only 1/16″ off in length from each other.

Okay, great!

But when I ran a straight line along the front surface of my “prop” . . . whoa!!!! Did I find a different story!  I made a not so pleasant discovery and was staring down the barrel of my wings being off in F.S. (Fuselage Station), sweep, whatever you want to call it, by a good inch [read below as I clarify this statement].

Now I will note that my first assumption from my previous confirmation (mentioned above) was that my wings were of course straight, it was the engine that was off kilter (not up/down as before, but left/right).

However, after taking a myriad of measurements I confirmed that my engine is exactly in line with the fuselage.  So it is a bit of an odd situation.  The engine is almost dead on with the fuselage, but it is off when compared to the wings (since the wings are off from each other).

To convey just how off they are, the straight line out 90° to the LEFT/port side from the prop hub and along the straight “prop” I have temporarily installed has the line crossing the forward outboard corner of the aileron just kissing the corner.  Conversely, on the RIGHT side the line crosses the outboard forward aileron corner an inch forward of that corner.  The same goes with the intersect point from “prop” to each winglet, with the right side being about 1.2″ forward than the left.

“Strange things are afoot at the Circle K, Ted!”  

It gets weirder.  Interestingly, all the flying surfaces are dialed into the nose. When I measure each wingtip, aft top winglet corner, etc. to the nose, I’m at most 1/8″ off between them one side versus the other.

Finally, I’ll report that the CS spar/strakes are a hair over 1/8″ off perpendicular to A/C centerline.

I did a quick dive into the plans on wing sweep, which can be up to 3″ off between wings and Burt says a Long-EZ will still fly just fine.

I also removed the left wing, added a thin washer inboard and a thick washer (vs thin) per outboard bolt.  I intend to add/swap washers to the right wing as well… more to report tomorrow.

For now…. yep, I’m calling it a night.

Before I got serious about prepping the boat for a day out on the water, I spent about 45 minutes in the shop pulling peel ply off the cured layups on the top halves of both the left and right winglet intersection fairings.

I then cleaned up all the peel ply boogers left from the peel ply edges & seams.

Cleaned up the edges of the layups at the transition of new glass to old glass.

I also razor trimmed and sanded the inboard “TE” of the fairings.

And sanded the very aft curved trailing edge to clean up the glass and avoid any puncture wounds.  I’ll trim to final length probably after the bottom side of the fairing is finished (I’ll assess).

I also sanded down the top of the vertical “wall” that rests against the rudder to remove any spikes and potential finger pokers, on both sides of course.  I’ll trim the edges of these inboard “walls” to the same height on both sides within the next day or two.

And that was the extent of my airplane building today.  Again, I am very pleased with the way these winglet fairings turned out.  Of course building two separate components like this about 25′ apart means that there will be minor variances, and there are… but I’d say that they match each other by over 95%.

Tomorrow I’ll jump back on the build!

Although not quite as hot as yesterday, today was still darn hot.  With activities limited to indoors (by me!), today was all about getting the topside winglet intersection fairings glassed.

Of course this meant first that I had to foam and shape the left side fairing.

As I did on the strakes, I simply cleaned up and flipped the tape-covered-cardboard dams that I used on the right side to pour the left winglet intersection fairing foam.

Note that as I did on the right fairing, I have the cardboard dam sitting on the edge of the fairing to keep a good 1/4-3/8″ bare edge (no foam) for ensuring a glass-to-glass seam along this fairing “TE.”

After getting the dam in place I then mixed up and slathered in 2 batches of the pour foam.

After the foam cured, I then started by trimming off the top with the wood saw before I then removed the dam.

A bit more major foam removal with the wood saw.

And then the first couple of rounds with the 2.8″ diameter fire extinguisher mounting “cup” (that I’m not using now) with 50 grit sandpaper wrapped around it.

After a few more rounds, including some smaller diameter Perma-Grit tools, I finally had a pleasing shape for my fairing.  I also tweaked the right side contour just a hair as well.

It was now time for glass.

First I want to share with you what I read recently on the COBA canard forums, where a guy mentioned that every pound he added aft of the firewall meant he needed 1/2 a pound of ballast in the nose.  I don’t know how specifically accurate that is but lately, between his comment and Klaus’s admonishment on build weight, I’m re-motivated and have been on a “diet” with the bird in regards to weight management (if only I myself could be so disciplined!).

I mention this to say obviously that I want to add as little weight as possible on these fairings.  Thus on the front half of the first ply I decided to use UNI vs BID simply because it’s a bit lighter.

On the aft side for the first ply I chose BID because I want to reinforce the “wall” that makes up the aft 1/3 of the outboard vertical component of the fairing… immediately adjacent to the rudder.  I also overlapped this aft BID a good inch forward of the front vertical edge of the rudder so that it would be secured to the actual winglet.

This ply of BID also overlaps just a bit onto the UNI.

Ply #2 is simply a single piece of BID that covers the previous plies and of course the entire topside winglet intersection faring.

After adding micro/slurry to the foam and wetting out the surrounding glass edges, I first laid up the forward ply of UNI, then the aft ply of BID.

These steps are representative of what I did on the right side as well.

I then laid up the top ply of BID and wetted it out.

And then peel plied the entire layup.

Again, I did the same thing on the right side.

I’m very happy with how these winglet intersection fairings turned out… I think they look pretty darn snazzy and the weight penalty isn’t bad either.  I’ll gauge the rigidity of fairing, but my initial thought right now is that I’m only going to use a single ply of BID on the bottom of the fairing over the intersection foam.  I’ll confirm that after these layups cure overnight.

Tomorrow is supposed to be another hot day, and I’m simply not going to cover up and wear a mask, etc. to sand down carbon fiber on a hot day.  Moreover, since I’ve been hard at work on the plane build for weeks solid now, it’s time to take my girl out on the boat for a nice day on the water.  In short, not a lot of plane-building is going to get done tomorrow.

Today was another very hot day, so no bottom cowling sanding yet.

I started off by simply pulling the peel ply, razor trimming and cleaning up the reinforcement layups on the right pilot armrest interior surface.  I’m happy to report this task is complete and pressing forward!

I also got another round of glassing in after cleaning up the corners and edges of the now attached CF-covered wood substrates making up the winglet intersection fairings.

After prepping the underside areas on both the left and right winglets/wings I prepregged the BID before laying it up.

First the left side . . .

And then the right.  Of course I peel plied the layups as well.

On the right winglet intersection fairing I constructed a dam on the top side for pour foam.

I then added in pour foam in 2 batches.

A bit later I pulled the dam borders off the cured pour foam.  Yes, it’s always way more foam than you need just to get everything covered.

I then took my trusty wood saw and started hacking (or sawing!) away.  After a few rounds in just a few minutes I had whittled the foam down a good bit.

I wanted a tubular object that was around 3″ in diameter to start my sanding & shaping with, and then planned on going smaller in diameter from there.  My previous fiberglass tube that I glassed for securing the fire extinguisher in the past measured just over 2.8″ in diameter… perfect.

I then wrapped it in a sheet of 50 grit sandpaper.

And went to town.  Here are a couple of pics after a few rounds of sanding, followed by some cleanup with the shop vac.

I got to a good stopping point after another few rounds of sanding to come back to tomorrow to finalize the shape.  It was getting late and I was hot and tired, so I wanted to reassess the final shape tomorrow before glassing this top side fillet on the right winglet intersection fairing.  Note that these pics below are all to the same level in sanding.

I’ll also note that I only did the right side —from foam pour to sanding— just to ensure that I didn’t miss anything or screw anything up!  Tomorrow I’ll do the left side and sand/shape it before glassing either side just to ensure the contours and profiles are the same on each side.

Again, in a way I’m just filling time waiting for slightly cooler weather to work my #1 priority: the bottom cowling, and in turn the exhaust pipes (yes, still… sigh).

Today was about knocking out some glasswork for upcoming tasks as well as remounting the lower cowling and assessing clearances with the engine now back in its original position.

Starting off, the outboard edges of my strakes tend to dip down right in the last 0.5″ inch around the perimeter of the strake edge.  This dip of course causes there to be a more pronounced uneven skin height level between the wing and the strake.

Instead of just slathering on a bunch of micro, flocro or flox, I wanted to both stiffen this edge up a bit while giving it some increased height to better match the wing.  On the end of both strakes I determined different thicknesses of BID that I was going to add, ranging from 1 to 5 plies.  3 plies was the most common addition, while I only needed 5 plies in one spot on each side, both about 3/4″ in length.

The width of the added BID started out as 0.4″… clearly it varied a slight bit as I manipulated the layup around the leading edge.  After prepregging the BID and getting it laid up, I then peel plied the layups.

A few hours later I pulled the peel ply and cleaned up the layups.  I may add another ply or two to the still considerably depressed spots, but the majority of the areas I’m calling good and feel comfortable with still a decent application of micro on the edge now.

Another glassing task that I have on my list that needed to be done before I consider this bird operational is a reinforcement layup on the pilot right armrest.
[I have just under 20 layup jobs that I’ve identified that need to be done (each task may require multiple layups).  About 75% of those must be done before the airplane goes airborne, others are mods such as baggage pods, wing LE landing lights, HUD mount bracket, etc.]

The plans call for 2 plies of BID, but I only used one.  Now I’m reinforcing the center area where I will push down when extracting my less-than-Twiggy self and getting into this bird.

Plus it was a fairly quick kill and I was trying to get out the door to meet Jess for a late dinner.  Not surprisingly, all the glass & CF I used were scrap pieces.

Here’s both sides of my Lantor Soric test piece that I laid up 1 ply of BID on each side.  One side was peel plied, the other not.  Yes, there’s air gaps around the perimeter where having a micro (or flox) transition would be good of course.

With a ply of BID on each side the thickness came out to almost 1/8″.  Also, as you can see on my well used scale (it means I’m building a lot! … ha) my ~2″ x 2″ test piece is a whopping 8 grams.

If you’re wondering why I’m interested in this Lantor Soric stuff, it’s because it will be the material that I most likely construct my wing/aileron fences out of… so far so good!

After returning home from dinner, I tucked away all the dangly stuff on the engine to allow me to mount the bottom cowling to assess clearances.

Yes, the gap between the spinner flow guide and the lower cowling is much tighter now, at just over 0.45″ … but I can manage that with no serious effort.  The big issue is the inboard left exhaust pipe, which the bottom of the 90° bend is now touching the cowling.  Moreover, my carbon fiber induction tube is just a hair away from the cowling as well… although not touching!

If you look closely you can see black Sharpie marks all over the bottom cowling.  I spent a good 45 minutes assessing my next steps, and yes… I will be recontouring major portions of the aft, mid to upper areas of the bottom cowling.  In addition, I will be extending the tail end transition of the RAM air scoop all the way to about 10″ in front of the boat tail “rudder” fin.  This is the only way I can see to add in some clearance to the air induction tube on the bottom of the cowling without a total rebuild.

More to follow of course, and I plan on getting started soon.  But we’re having another major heat spell… I went to have a glass of red and ponder my bottom cowling fix actions on the front porch at 11pm tonight and it was over 90°. . . clearly just too darn hot.  My point is that I will not be doing a lot of sanding on the bottom cowling during super hot days, so it may be a few days before I get a somewhat cooler day to knock that out.

I learned from my Air Force fighter pilot uncle that dogfights are all about energy and angles.  Pretty sure that’s one of the principle themes of what is taught at Top Gun and other Fighter Weapons Schools.

Well, I’m clearly in a dogfight as well in getting this bird built… and just as the U.S. military did with Top Gun, I needed to refocus on energy and angles a bit in regards to my energy producing device, aka engine.

But first… I started out first thing this morning to get some glass curing.  I had planned on knocking out 3 sets of layups before throwing myself headlong into the upper cowling install.

I got this one set below knocked out before I started messing with the engine angle. Here we have the BID going onto the top side of the left winglet intersection fairing made up of carbon fiber on wood.

And here the initial top side layups are complete and peel plied on the left winglet intersection fairing.

And I I then did the same on the right side.

When I mounted the 3D printed mockup mod of the prop spinner flow guide and subsequent addition of the spinner, I wasn’t focused on the ANGLE of the aft blue face of the flow guide.  I texted some pics to my canardian buddies and in one reply, Marco stated that it may just be an optical illusion but that my spinner looked a little pointed upwards going aft.  I thought he was just being a bit snarky and passed it off with a snarky comment back.  Case of the snarky comment closed… or so I thought.

Clearly the vinyl record sized flat disc that now occupies the very aft of the airplane (with the spinner off) provides a much larger visual reference plane to observe than just that of the more diminutive prop extension mounting flange.

And then I saw “it.”

As I was heading back into the house I circled wide around the left winglet and paused to look at the top cowling.  Once I saw the angle of the bright blue disc on the aft side of the bird I could then clearly not “unsee” it.  It was glaring that my prop angle was off… notably.  I now understood what I initially thought as just a punky comment from Marco was actually a very spot-on observation of a detail that I had hugely missed.

Here’s a closer look at the prop angle.  I messed around with a 2×4 and other material to assess this forward leaning prop.

I knew that with a lot of weight in the nose and having not attended to the tire air pressures in months, that the nose was probably a little low… plus I know the shop floor angles down towards the front doors.

I checked the longeron angles and they confirmed the nose was in fact low. I put a 5/16″ piece of wood under the front tire and also filled it with air.  My longerons are always a hair of a degree off from each other, and at this point the left showed 0.1° degree down and the right flashed between 0.2° and 0.3° down… for this exercise I called it 0.2° down and averaged the total at 0.15° nose down (all this actually preceded the prop angle pics above).

I dug back into the plans to confirm that my engine mount was attached in the proper configuration.  I measured the top aft edge of the mounting cup on each side, from the firewall and also the bottom engine mount cup as well.  The F.S. reference point in the plans is from the front face of the firewall, which is F.S. 125.  The most important data point here is the difference between the top and bottom W.L.’s of the engine mount as spelled out in the plans: a 0.25″ delta.

My measurements, as shown here are about as spot as can be measured: 0.25″ difference on the left, 0.26″ difference on the right.

I took the bottom cowling off and spent a good hour rigging up the engine hoist, and removing the shims off the bottom engine mounts.

With the bottom engine mount bolts only finger tight, I rechecked the angle of the engine at the prop extension hub.  Interestingly, with a 250’ish pound engine —after removing 0.1+” shims— the angle only dropped from 1.5° to 1.2°.  That told me that engine weight alone was not compressing the Lord mounts to any real amount, which is what I somewhat expected.

After tightening the bottom engine mount bolts to spec —sans shims— I was now looking at only a 0.6° angle on the prop extension face.  But don’t forget the nose is about 0.15° low… so the actual angle is between 0.5° to  0.45°.

In researching engine mount shims and in also talking with the Lord Mount folks, it’s not surprising that engines tend to to drop a bit after the mounts get “exercised” and the engine settles into place after its operated.

Again, a closer shot.  At 0.5° aft engine up —clearly less than a degree— it’s close to the center mass target and the tendency in the future is for it to settle.  Better this scenario by far than that of the engine angle being too low.

Out of curiosity, I set the level with the water bubble just touching the aft line and measured the gap at the top between level and prop stud: 0.05″ engine drop until within the minimum “level range.”

With the bubble centered that gap is 0.079″… so at a hair over 1/16″ the engine will be exactly level.  Considering I need to still mount the prop, crush plate, prop bolts, Belleville washers, spinner and flow guide, not to mention the engine baffling, and that the engine hasn’t been run to settle into the mounts, I’m simply not going to worry about this angle from here on out.

What I do have to worry about is component clearance with the lower cowling. I will state emphatically that it is time to put this engine vs cowling clearance issue to a stop. If I need to start hacking up and reshaping the bottom cowling I will proceed to do so.

After the latest rounds of engine shenanigans, multiple hours later, I finally got around to pulling the peel ply and tape off the winglet intersection fairings.  I had planned on laying up a single ply of BID along the fairing’s underside, both along the wing TE to fairing seam and also along the winglet to fairing corner seam as well… but it was late and I wanted a break from the engine angle drama.

I will note that I weighed the trimmed carbon fiber/wood fairing structures together at 1.34 oz.  I then added the glass weight and doubled that to estimate the epoxy weight as well.  Currently the added weight is around 3.4 oz.  I expect with foam, micro and glass that the estimated total added weight of these fairings will be about a pound.

Once I add and shape pour foam on the top to blend the winglet intersection fairing into both the wing and winglet, with a pleasing shape radius, I’ll most likely significantly trim down the height of the mini wall that will create the outboard upright of the fairing, against the bottom inboard rudder.

And with yet another long (and dramatic) build day under my belt… yup, calling it a night!

Thankfully I was greeted this morning with Max still whirring away printing out the prop spinner flow guide mod test mockup.  It would still take nearly 2 more hours to finish up the print, which is when I grabbed this pic here.

I then set it next to my current flow guide to show the stark contrast between the shape and size between them.

Another couple shots of the current flow guide and the test mod mockup.

Entering the shop I immediately chased out 2 squirrels that think the workshop is their residence.  I then saw this massive spider on the wall… at least 2.5″ inches across the legs.  I yelled at him for letting those damn squirrels into the shop!  If you’re gonna hang around ya gotta do some work!

I then installed the test mod mockup for the prop spinner flow guide.  It was a tight fit, but it went right on.

Here’s the clearance between proposed prop spinner mod configuration and the lower cowling… it makes me think that I may just very well add a very slight curve to the flow guide.  I’ll assess and see.

Another couple shots at the side of the flow guide mod.  I’m thinking I may add to the flow guide a bit by simply taking the front edge straight forward with a 1″ lip… with a nice radius flaring out to the aft expanding flow guide.

I then mounted the prop spinner.  Although my measurement on my 3D printed flow guide is correct, I think that the nearly 1″ wide mounting flange on the flow guide for the spinner is not a straight cylinder as I printed it out, but actually expands out a hair as it goes forward.

The spinner was a hair bit wider in diameter than the flow guide and I needed to put some duct tape internally to make it a snugger fit.  I then set the top cowling in place.

Of course this still provides a good idea as to how the spinner will look installed. Remember, the top cowling and exhaust pipes have yet to be trimmed to final configuration.

After a bit of staring down the prop spinner and pondering various aspects of its upcoming installation, I then got to work on the winglet intersection fairings.

I’ll note between last night and today I did a fair bit of research (RE-research actually) and observed that various builders had used a 2-ply BID layup as the foundation for their fairings.  I decided to use very light wood pieces cut nearly to the exact shape I wanted and then add carbon fiber for stiffness and rigidity.

The trailing edge of my left wing is a hair thicker than the one on my right wing, so I used 1/16″ Balsa wood (which I just bought) for the substrate on the left and some on-hand 1/32″ Birch plywood for the substrate on the left.  The difference of thicknesses in these areas will be flushed out with pour foam and subsequent micro finishing.

After cutting the actual left and right wood substrate pieces, using the cardboard template I made up the other night, I then cut some carbon fiber and peel ply for each one as well.

I then laid up the carbon fiber on the wood substrates and peel plied the layups.

I’ll point out that the carbon fiber is only going on these pieces and will not be securing any component to any other component… thus with these in place between the wing and winglet, and secured with E-glass fiberglass, any twisting, flexing or bending moments will be primarily at the joints secured by the fiberglass—and not specific to these carbon fiber reinforced wood pieces.

Since these were fairly small layups I used fast hardener, and had enough epoxy left over in my cup that I didn’t want to waste it.  I quickly unboxed my roll of Lantor Soric and cut approximately a square inch off of it.

I then wet out a scrap piece of BID, slathered up both sides of the Lantor Soric piece before covering it with another ply of scrap BID.  I had to hurry because my epoxy was starting to cure in the cup and was turning the consistency of thick honey.

After the carbon fiber and peel ply was in place, I then covered each of the fairing pieces with Saran wrap before piling on some sheets of steel and weights to compress the carbon fiber/wood substrate assemblies and keep them nice and flat (note my trimmed Lantor Soric test piece).

A couple of hours later I removed all the sheets of steel, the Saran wrap and the peel ply.  I then left the carbon fibered covered wood winglet intersection fairings to cure overnight.

And called it a night!

I figure if I’m going to discuss modifying the spinner flow guide that ya’ll might want a reminder of what the current one looks like.  I’m sure you’ve seen this “lampshade” style flow guide before since it’s probably the most common, or close to it, for the ‘Hershey Kiss’ style spinner.

Here’s an inside shot as well.  This flow guide is designed to mount to the prop flange on the prop extension side and then butt up against the aft side of the flywheel on the forward side.

Again, in its current stock state this “lampshade” style flow guide will not fit into the aft opening of my cowlings.  To use the Catto prop spinner I need to modify the flow guide shape to be more along the line of the style Klaus Savier sells on his Lightspeed Engineering website:

Although it’s not overly visible, notice that the flow guide above does not butt up against the aft face of the flywheel, but rather curves around and free floats over the prop extension.  In order to install the flow guide it clearly has to fit around the prop extension prop flange, which is normally 7″ in diameter.

I plan to reuse the aluminum mounting plate, mounting flange and nut plates from the current flow guide, and remove all but the aft 1.3″ of it.  Moreover, in my design modification I need to ensure that its configuration avoids the cowlings’ aft opening edges, thus the resulting design on mine is not curved like the one above, but rather straighter.

After getting the bolt patterns dialed in and test-fitted, I then modeled up the rest of the modified prop spinner flow guide in Fusion 360 CAD:

Here’s another shot of the aft face of the flow guide with the mounting flange for the spinner and the bolt stud holes.

Finally, a look at the inside of the new, modified prop spinner flow guide.

As I discussed yesterday, since “Geeks gonna geek!” for no real damn good reason, I spent a good 2-1/2 hours recoding and re-tweaking my firmware settings because somewhere there is a momma’s-boy that apparently needs to have a sense of purpose in life by arbitrarily changing crap!!

But I finally got it.  One more round of this BS and I’ll be changing my firmware from the 3D printing world’s darling, Klipper, back to something stable and boring like Marlin.

Here’s the initial part of the print: the aft face of the flow guide.  I started with blue ABS but didn’t want to burn through the entire roll of it.

Although I made the mounting face only 0.05″ thick, for something this big around it took a good bit to lay down that much plastic.  If you look closely at the screen below you can see at this point this thing had already been printing for 5 hours and 11 minutes, with another estimated 12-1/2 hours to go.  And that’s at a speed nearly twice as fast as my other 3D printers!

About an hour after I grabbed this shot I swapped the filament out to a fresh new roll of silver ABS to ensure that the print didn’t run out of plastic in the middle of the night.  Plus I didn’t want to use all my blue ABS in this one print.

A bit later in the evening I sanded the micro I had applied to the bottom inboard edges of the rudders.  I also removed all the protective tape and cleaned up the surrounding glass.

Yes, definitely not good enough for the actual finish of the rudders, but good enough for what I’m doing here: just getting a decent straight fill for the tape to sit straight on….

I then taped up the bottom of the rudders and cut the associated peel ply for the upcoming layups for the winglet intersection fairing, which I had planned on doing tonight.

But I hadn’t sat down and really thought through my layup schedule from A-Z, and it was starting to get a bit later in the evening.  Jess had just arrived, being sweet to come over and cook dinner, so I decided to kick this layup can down the road until tomorrow.

After a great meal with Jess, and then switching the filament over to the silver roll… and with all looking good with Max (my new 3D printer), I called it a night.

As I prepare to mount the upper cowling I want to know if & how my Catto prop spinner, specifically the “lampshade” flow guide portion of it, can be modified to work with my cowlings.  If I need to make any minor adjustments or allowances for the prop spinner when installing the top cowling and mating it to the lower cowling, best to know now.

What I do know is that the current flow guide (“lampshade”) does NOT fit and will need to be modified.  I’m pretty sure I mentioned in an earlier blog post that I had a good conversation with Mike Toomey on how he rolled his own spinners based more on Klaus Savier’s spinner design, again, specifically focusing on the flow guide portion of it.

From my conversation with Mike T. I came up with my inital plan on how to modify my flow guide to fit into my tight Melvill cowlings.  My work today is a continuation of flushing out that possibility by creating a mockup of my proposed flow guide to A) test its fit with the spinner portion, and B) have it in place during the upper cowling installation to know my flow guide mod will work/fit.

Since the Catto ‘Hershey Kiss’ canard prop spinner is made with a hex pattern carbon fiber, I called Catto 2-3 weeks ago to see if I could get my hands on some.  They obliged but we’ve been playing telephone/text tag with a good week-plus gap in comms to finalize price and quantity.  Well, today I finalized the deal to have them ship me a couple yards of “their” CF to allow me to reconstruct a flow guide using their hex patterned CF.

Phase I of the flow guide mod is of course ensuring it will fit in the aft cowling opening.  So I’ll reiterate that I feel this is a prerequisite/commensurate task early on in mounting the upper cowling.

I grabbed all the dimensions off the current flow guide for the middle opening and prop bolt hole studs and modeled them up in Fusion 360 CAD.

Once again the IT geeks got the best of me when, without thinking, I fired up my new mo-jamma 3D printer and promptly updated the firmware when I was prompted… then the issues began!  Some of my previous Klipper firmware configurations apparently are no longer recognized in the latest version of Klipper so I am getting errors.  I thought I had done enough research to clear them out, but then my model ended up printing about 1/4″ over the plate… a couple of times.  After an hour+ of playing Johnny F- Around with that I called no joy and used the smaller new 3D printer. (Ugh!…. Geeks!)

My first test version of the bolt stud holes had the pattern just a hair in too close to the center and they all needed to be moved out just a skooch.

I moved all the holes out 0.017″, and reprinted the mockup.  The new pattern worked a treat but I then discovered the holes themselves are just a hair too tight for a mockup.  For actual installation they are probably perfect.

Here’s another shot of the #2 mockup with the correctly spaced bolt hole pattern.

I’ll add about 0.008″ to each hole just to give them a hair more clearance for getting this thing on and off, and press forward with the design.  The reason I wanted to use the bigger 3D printer is that the new lampshade model may be too big for my smaller 3D printer.  We’ll see, but I may be doing some more 3D printing troubleshooting tomorrow though.

I of course want to get this thing printed & complete so I can press forward with the upper cowling install!

I’ll also note that I had a good conversation with Marco as he was on his way to his hangar to do some brake line work on JT, his Long-EZ.  His timing for calling was perfect and I had him grab a bunch of pics with various dimensions of his prop in relation to the aft cowling opening, exhaust pipes, etc. as references for me as I press forward in my cowl and exhaust pipe installs.

First off, the PMag arrived back this morning from Brad & Gang at E-Mag Air Ignitions in Texas.  That task is complete… now just have to get the cooling air duct constructed for it and get it back onto the engine.

Last night I started messing around a bit with some cardboard and tape just to get a general idea of the winglet intersection fairing.  I was just going out to the shop to grab something and had a box in my hand that was going into the recycle bin… it never made it.

Since I didn’t have my phone with me during my “quick” jaunt to the shop, I grabbed these shots this AM.

Again, this is just some preliminary/visual thinking out loud regarding this fairing.  I suspect I’ll be employing what Dave Berenholtz calls “eyeball engineering” quite a bit on this effort.  Moreover, mimicry and outright plagiarism of Dave B. and James Redmon’s fairing designs will be the foundational hallmark of this undertaking.

I then spent a good half hour each side pulling peel ply off the wing/strake/CS spar layups from yesterday, and the subsequent clean-up of all the peel ply boogers.

I then marked and cut the dividing lines between the respective wings and strakes, based off my previous marks that I had made prior to the layups.

Here’s the left side:

I did the same thing on the right side as well.  Another significant task in the “done” column!

Another serendipitous find I made late last night as I was checking up on all the FB canard group posts was this little gem from Burrall Sanders.  I have been pondering in my mind just how to mount my oil cooler in a lightweight manner while still being able to remove the bottom cowling without it causing pain & drama.

I thought about mounting it to the CS spar with as lightweight as possible mounts, then turned that into just mounting it to the bottom cowling —par normal— with temporary mounts that I would install on the CS spar just during lower cowl removal.  And then I stumbled upon this option: mounting the oil cooler full time to the left wing flange, with some screws also securing it to the lower cowling (to keep the seal tight).

I will seriously consider this option given that it’s a reasonable assessment that the cowlings are taken off and put back on way more often than the wings are… so I think this could be a very viable solution for me.  More to follow.

Tomorrow I plan on starting the journey of the top cowling install, interspersed with other likely magnificent surprises (ha!) as well.

Calling it a night!