Chapter 23 – Exhaust pipes welded!

I started off this morning by pulling the now cured #2 cylinder baffle —with the fin/baffle standoff support curve integrated into it— off of the aft side of cylinder #2.  I had put a heat lamp on it since the weather (and shop) was much cooler overnight.  I assessed the baffle a bit —all looked pretty good— and then set it aside to remove the bottom cowling to allow removal of the left outboard/cylinder #3 exhaust pipe.

I commenced to remove the tape securing the halves of the exhaust pipe together at the near-center cut and then cleaned all the tape gunk off with Acetone.

While I was doing all these shop tasks, I had already pre-heated my kitchen oven to 400° F and was baking my previously “super-soldered” brass oil sump standpipe fitting.  My goal was to separate the fitting from the standpipe tube to allow James to braze it with some 1/16″ Silicone Bronze welding rods I picked up to allow TIG welding brass. Well, an interesting thing happened, or didn’t happen… whereas at 400° F previously I was able to remove the soldered pipe from the fitting, now it wasn’t budging. Hmmm?

I threw the standpipe assembly in the truck as well and headed out to James to weld the exhaust pipe, and also have a discussion on the standpipe.  My thoughts, in composite parlance, is that I had essentially post-cured this sucker and that it was now battle-tested to withstand 400° F without any issue… very interesting.

Again, it’s a good hour over to James’ shop and since Jess had a light work day I brought her along.  Unbeknownst to me, Jess’s mom is from the same area (“out in the sticks”) where James’ shop is… so after James had welded up the pipe an elderly friend stopped by and a whole conversation of who-knows-who ensued.   Combine that with a late lunch/early supper in Jacksonville and we didn’t get back to my house until very late afternoon.

And here we have the final piece of the puzzle (better be!) with the left outboard/ cylinder #3 exhaust pipe welded back together.  Now I can start on the final configuration of the tips in earnest.

BTW, James confirmed my theory on the soldered brass standpipe.  He also quipped that if I’m seeing over 300° in my oil sump that I’ve got lots worse issues than the standpipe… good point James, good point! <ha>

Back in the shop I got to work on the cylinder #2 aft baffle with it’s new integrated standoff bump.  I cut a ply of CF to fill just where the standoff support form was located and another full ply of CF to hold it all together on the interior of the baffle.  I then mixed up some HTR-212 epoxy and laid in the small filler ply of CF (pic 1) before laying up the interior ply of CF (pic 2).

I then of course peel plied the layup.

I let the baffle cure for nearly 2 hours to tack up before then setting it back onto the aft side of cylinder #2 (which I taped up completely to protect from any errant epoxy).  I taped the baffle securely in place to the cylinder since this will be the final cure and set a heat lamp on it while it cured overnight (much colder tonight than last night).  I’ll also note that the cylinder #2 fin/baffle standoff support mold was still in place on the cylinder to ensure the final shape is as optimized as possible.

And with that, I called it a night!

 

Chapter 23 – Inner baffles… end is near!

I actually started off today out in the shop to do some more inner baffle layups (see below), but apparently in my haste to get stuff done didn’t grab any pics of the initial layups.

After I got the layups situated (thankfully the weather went into mild mode over the last couple of days) I modified my cylinder #2 fin/baffle standoff support template to a simple rectangular shape based off my test fit yesterday.  As a reminder, here’s what that looked like:

After I got the major dimensions dialed in on my CAD model, I then created a vertical arch that is 1/4″ high in the center for my fin/baffle standoff support mold.  I kicked off the 3D print of the mold and then went out to the shop to prep the cylinder for the mold.

Here’s the cylinder #2 fin/baffle standoff support mold taped to the front of the cylinder.  After I got the mold placed, I then spent a good half hour trimming and sanding the top and bottom baffle segments to get their mating edges even and just kissing the top and bottom edge of the mold.

I then taped up the mold, which then allowed me to secure the cylinder #2 top aft baffle segment in place (pic 1).  I mixed up some HTR-212 epoxy to apply peel ply to the mold only, and then wetted out the surface of the top aft baffle segment (pic 2).

I did some dry runs on the the bottom aft baffle segment before adding tape to the inside of it.  I then laid up the single ply of CF (note: same print as spinner!) onto the free and unattached bottom aft baffle segment before securing it into position with its inside taped surface… I pretty much had to work it this way since the oil return line is in the way and I didn’t want to have to try to layup the CF around and under that oil line.

After I got the ply of CF laid up and trimmed I then laid a piece of plastic over it to provide that glossy, non-bumpy surface like all the other inner baffles have.  I then left it to cure overnight.

After getting the aft baffle on cylinder #2 squared away, I then pulled the peel ply and did some trimming on the narrow top outboard inter-cylinder baffle segments.

Here’s the non-cylinder mating side of those baffle segments… and I’ll remind everyone that these will get merged (separately, one per each side of the engine) with the larger end baffle segments to create the top outboard inter-cylinder baffle segments…

And to be clear, here are a couple shots from a couple different birds on how the top outboard inter-cylinder baffle looks when completed:

I’ll note that tomorrow I’ll be heading out to James’ shop to get the last exhaust pipe welded up, so it will be a slightly lighter build day.

Chapter 23 – Cylinders 2 & 3 end baffles

I had some decent build plans for today but it turned out to virtually be a non-build day in most regards.  Last night I got an email saying that our monthly EAA meeting was this morning at a local restaurant.  I texted the new Canardian in the area, Guy Williams, about the meeting since I wasn’t sure if he was on the email.

I also received a text from my friend asking if I could watch her daughter, aka “my little buddy,” while my friend went to a doctor’s appointment.  No problem there either.

After the EAA meeting, Guy and I went to the airport to check out his Long-EZ.  It’s a beautiful classic built in 1982.  He and his dad, who owned it for many years before Guy took ownership, converted it from an O-235 to an O-320.  Guy moved out here this summer from Tehachapi, CA… home of Marc Zeitlin and Mike Melvill.  Thus Guy clearly had plenty of expert help on hand to assist with engine conversion, etc. on his Long-EZ.  And of course it’s great to have another Canardian at the airport, especially one of the Long-EZ persuasion!

Now, in my mind I figured a doctor’s appointment would take an hour or two at most, and although I only know that it was NOT anything serious, this appointment ended up being over 4 hours… that had me on kid-watching and entertaining duties.  By the time I got home it was well past 4 pm and I was due to have a dinner/evening out with Jess… so my already shortened work day was severely truncated by events that plopped onto my schedule just the night prior.

Out in the shop I pulled all the laid up baffle segments off their respective molds and pulled all but one piece of peel ply (only because it has such clear baffle edge trim markings on it).  I can tell you the added 6-8 hours of cure time with these baffles on the molds was felt significantly as they were MUCH harder to get off each mold!

Here’s the tally, starting CW from the lower left corner:
– “Old” top outboard wide inter-cylinder baffle (to be joined with narrow baffle segment)
– Opposite side of above, just laid up… now just need to layup narrow parts for these
– “Old spinner print CF” end baffle now relegated to duty on front of cylinder #4
– 2 pcs for cylinder #2 aft end narrow baffle that will get middle fin extension area added
– New “spinner print” aft end baffle with much better looking CF for cylinder #1
– New narrow end baffle for front side of cylinder #3

Also, before I headed out to the shop I quickly drew up in CAD and then 3D printed an initial template for the cylinder #2 fin extensions and associated baffle curve over these extensions.  Here’s the result that I temporarily taped up in place.

And an idea of how the top and bottom baffle segments will get melded with the upcoming semi-circular cylinder fin standoffs.

With that, it was time to get inside, clean up and head out for a Saturday evening with Jess.  Tomorrow I definitely intend to get at least the 2 partial narrow baffle segments glassed up for the other half of the top outboard inter-cylinder baffle assemblies that need to be floxed together back-to-back to make up those baffle segments.  I would also like to get some machining done, with the baffle extensions getting made to confirm the configuration for me to then “glass” (CF) up the gap on frontside cylinder #2 baffle.

Moving forward!

Chapter 23 – Inner baffles Round 3

I started off this morning by pulling the two cylinder base inner baffles of their molds, as well as the new cylinder #1 aft end baffle off its mold.  The big reveal I mentioned yesterday is that they’re sporting the same CF print as the spinner and flow guide!  The cool thing is that these will all be fairly visible on the aft side of the engine when you look into the aft cowl opening.

Unfortunately, this CF is a bit thicker weave and I think I was a hair thin on epoxy in a few spots so the spots look just a tad dry in the light (just cylinder #1 baffle).  I have no doubt that it will still work and that it’s mainly cosmetic, but I’ll be relegating this new cylinder #1 aft end baffle to the frontside of cylinder #4, where it’s not as visible.

Along with the cylinder baffles, I laid up the second set of “accessory” pieces that are shown along the bottom of the pic (from L to R): the top inboard inter-cylinder baffle plate, the bottom outboard inter-cylinder baffle, and the angle bracket that screws into place between the cylinders at the top to secure the top inboard inter-cylinder baffle plate.  All told, this completes the cylinder base baffles and the “accessory” baffle parts.

For the larger cylinder end baffles that still left a redo on the cylinder #1 aft end baffle to get better epoxy coverage, and another partial end baffle for the other side top outboard inter-cylinder baffle.  Again, these partial end baffles will be merged (separately) with a pair of also partial narrow end baffles (below) that at full length are for the front side of cylinder #3 and the aft side of cylinder #2.

Speaking of which, I prepped the narrow end baffles by taping them up first with blue tape (pic 1) and then using the Tyvek tape on top of that as a mold release (pic 2).

I’ll note that on the cylinder #2 baffle I added a lip [a curl would be much harder to fit into place with oil line present] and a curl on the cylinder #3 baffle [also an oil line present, but at the forward side of the cylinder the bottom length of the baffle will be shortened with the curl positioned much higher up/closer to cylinder].

I then did the inner baffles Round 3 layups, which from left to right is as follows:
another partial end baffle for the other side top outboard inter-cylinder baffle;
the redo on the cylinder #1 aft end baffle;
top & bottom sections of aft cylinder #2 baffle (middle to be laid-up over fin extensions);
narrow front side end baffle for cylinder #3;
extra top inboard inter-cylinder plate (if/when fuel spider goes underside…bottom of pic)

My last point of note for the day on the build is that I spoke with my welder, James, who has been quite busy as of late, to set up an appointment on Monday to get the last exhaust pipe (cylinder #3) welded up.  From there I can do my end trimmings and final tweaks to get this exhaust pipe saga closed out.

Tomorrow I plan on doing another round (hopefully final) for the engine inner baffle layups.  This should get me close to having the full set I need to start trimming these inner baffles up and installing them all.

Chapter 23 – Inner baffles Round 2

I started off today with a couple hours of research.  Although the weather was forecasted to be significantly warmer than yesterday, I figured I would wait until the afternoon to start work in the shop to let it naturally warm up a bit.

My research focus was on something that Andreas Christou discusses in his article, Design for optimal cooling efficiency, where he points out that the design of Lycoming type cylinders leaves the front of cylinder #3 and the aft side of cylinder #2 with virtually zero depth on the cooling fins (in a small area it’s literally just flat).  His suggestion as depicted in this diagram from his article (and yes, it’s upside down for us Canardians) is to create a standoff on the cylinder to extend —or literally create— the fins to support the baffle along that segment of the cylinder.

I had a discussion on this with Mike Beasley over lunch when he and Marco came down to visit me and Jess.  He mentioned that Dave Anderson had done a “washer trick” or something to create a gap on the #2 cylinder to account for this issue, and that Dave had purportedly resolved his hotter #2 cylinder cooling.  I’ll further note that from my gathered info, from accounts of other pusher drivers, and specifically from Mike and Marco at lunch: cylinder #3’s CHT on our birds doesn’t seem to suffer from a lack of a standoff.  We concurred that it was most likely since it was just aft enough and in direct line of the incoming cooling airflow, both on NACA and armpit scoop cooled EZ’s, that it seemed to cool as well as the other “tamer” cylinders.

A couple days ago I hit up Dave Anderson on FaceBook to ask him “How he done it?!” He said he was heading out to the airport in a day or two and would grab me some pics of what he had done to resolve this issue.

Here are the pics that Dave grabbed for me showing his cylinder #2 aft baffle configuration.  Note that the outboard baffle is simply off/away from the cylinder fins by about 3/16″.

And here’s a closer shot of that standoff.  I asked Dave the difference it made and he said it was considerable, about 100° F cooler for that cylinder.  Pretty impressive in my book!

Then, as I was perusing through the earlier issues of the COBA Canard Aviation Magazine this morning, mainly looking for Steve Beert’s excellent write-up on the engine inner baffles, I ran across an article by Dave Adams from April 2021, Issue 142, that showed what he did to resolve/mitigate this cylinder #2 standoff issue.  Funny thing is when I first started looking at the article I just quickly noticed the name and thought, “Dave wrote an article on this, why didn’t he just tell me to read it??”  After another look I realized it was Dave Adams.  Oops! (So many Dave’s in the canard world, eh?!)

Here’s a shot out of that article of some thin standoffs Dave added to the aft side of cylinder #2 to create the standoffs I’m talking about.

Moreover, Dave Adams solved another head-scratcher for me as well with the depression in the fins at the top of all the cylinders.  When the baffle covers this part of the cylinder fins, clearly it lets air escape out the sides.  Dave added mini walls at the outboard fin on each side to keep the cooling air channeled in the middle.  Quite smart and I intend to follow suite… because as we all know, any extra bit of cooling we can get on these birds —without adding drag!— is golden.

At this point in the day the weather had warmed up a good amount, so I headed to the shop to do Round 2 of the 2-ply CF layups on the inner baffle forms.

Starting in the top left corner in the pic below are the final 2 base cylinder (inboard) baffles [I have a surprise reveal on these and the other cylinder #1 aft baffle <far right in pic> tomorrow!].

The baffle form in the center of the pic with about half of it covered with the CF layup is the first of 4 of these separate cylinder “end” baffles that will get paired off and combined back-to-back to make the top outboard center baffles.

Finally, along the bottom row we have the second set of the bottom inter-cylinder baffle (V shape), the top inter-cylinder securing angle bracket (L shape), and the top inboard inter-cylinder baffle plate (cross shape).

After adding some peel ply I then left this round 2 set of inner baffle layups to cure overnight.

Chapter 23 – Final cowl clearance

Today was a very cold day weather-wise so I didn’t do any layups in the shop since the preferred working temp for the HTR-212 hi-temp epoxy is a minimum of 80° F.  And I just didn’t want to have to jump through all the hoops of using heat lamps and heaters, etc. to keep the layup and curing areas warm.

I did mount the bottom cowling to check out my latest clearance protrusion.  Not something that I of course prefer to have present on the bottom cowling, but a must to provide necessary clearance with the #2 cylinder exhaust pipe.

Hindsight is always 20/20, so knowing and seeing now what I couldn’t really get when I started, I could have easily taken this cowling bump about 1/4″ inboard and about 0.150″ less in height at the vertical edge to make it a bit more diminutive in the airstream.  Hard to see all that when you’re visualizing and just going off the marked up Sharpie borders of the exhaust pipe.  Yes, I may have a bit more constant drag caused by this form, but I also alleviate any contact between exhaust pipe and lower cowling.

On the inside I checked not only the exhaust pipe clearance, but flipped the EGT probe securing hose clamp around 180° so that the screw portion of the clamp was facing forward.  I then checked the clearance under the hose clamp screw and it’s right about 0.47″… close enough to 0.5″ clearance so I’m calling it good.  That of course provides plenty of clearance for the exhaust pipe itself.

This hose clamp repositioning also gets that clamp screw out of the line of fire to allow freer access to the spark plug for install/removal, but then also adds to the bottom depth of the exhaust pipe as I showed in this pic a few posts back.

I then spent a bit of time pulling the now cured Round 1 inner baffle 2-ply CF layups off their respective forms.

Here’s a closer shot to show the weave of the CF.  Thankfully not only did the parts come off the forms easily enough, but they didn’t tear up the forms… easily allowing another round (#2) of layups to hopefully knock out all the parts required for these inner baffles.

With that being said however, tomorrow is forecasted to be even colder than today, so I will probably get some much needed personal stuff done and forego shop ops altogether, other than just trimming the excess CF off these parts.

Pressing forward… haltingly!

Chapter 23 – Inner Baffle Forms

Well, after 2 days of missed delivery attempts from FedEx, I finally got the engine inner baffle molds delivered and in my hands.

I unboxed all the molds and did an inventory to make sure I had all I needed.  I was a bit confused at first because I didn’t see the top outboard inter-cylinder baffle, but after a few hours I had a bit of an epiphany and realized that you need to make another pair of each of the front and aft side cylinder baffles, merge those together and then trim them to make up this top inter-cylinder baffle.

These forms were made to use a higher temp epoxy than I am using, although I am using a decently higher temp epoxy with the HTR-212.  I’ll remind everyone in a post I made a while back that our resident community guru, Klaus Savier, noted that CF engine inner baffles could be made with MGS-285 and slow hardener.  This stuff beats out even the MGS concoction.

In addition, the high temp epoxy used on these forms was by design meant to have the inner baffle CF layups cured right on the form, using wax, PVA mold release, et al.  I specifically chose the HTR-212 high temp epoxy since it cures at room temperature, and doesn’t need to have the layups cured on the forms.

This of course creates another challenge in protecting the forms from the layup, which then entails a rather time consuming tape-up job for each form… but nonetheless that is what I did: starting first with blue painters tape, and then covering that with Tyvek house wrap tape as a mold release.

I wanted to get some parts laid up, since clearly there are a lot of them!  Round 1 consisted of the larger cylinder baffles that go on the front of cylinder #4 and the aft side of cylinder #1, respectively.  These were the trickiest to tape up so I wanted to get them knocked out.  In addition, the smaller pieces only have one form, and 2 parts from each form are required so I wanted to get the first round on these knocked out as well.

After taping up the forms, I then cut out 2 plies of CF for each part and laid them up.  As par usual, I’ll be modifying these inner baffles to meet the specific requirements of my engine.  I also plan on following some of the guidance laid out by both Mike Melvill and Andreas Christou on their implementation of engine baffles to optimize air flow and thus cylinder cooling.

After a short dinner break I headed back out to the shop for Inner Baffles Round 2. This time the focus would be on the inboard baffles that go around the cylinder bases (closest to the crankcase).  Here we have 6 cylinder base baffle forms taped up with blue painters tape.

My plan was to tape up all 8 (2 per cylinder) and get those laid up, but between 2 of them having a “pimple” in the middle area of the form and the fact that it was taking so darn long to tape them up (and getting late!), I decided to just knock out 6 —3 pairs— of the cylinder base baffles.

Here they are a good hour plus later after I cut and laid up 2 plies of CF on each one.  I cut up scrap pieces of peel ply and then applied 3 strips to each baffle segment for the subsequent attaching of these baffles to the cylinders with RTV (Toyota #103 is recommended, so I ordered some).

Here we have another shot of the 3 pairs (out of 4 total required) inboard cylinder base baffles 2-ply CF layups.

I’d say I got roughly half of these inner baffles “glassed” up tonight, which is pretty darn ok in my book.  Tomorrow I’ll knock out a good bit more.  I will note that the weather is getting cold so I cranked up the shop heaters and will need to keep heat lamps on these laid up baffles for their ~24 hour cure.

Chapter 23 – Right cowl wrap-up

I didn’t get a lot done today in the shop since I was getting ready to spend another good portion of the day/evening in New Bern watching the AeroShell Aerobatics team do their stuff (excellent by the way) and then a dinner out.

I did get the peel ply pulled off the bottom cowl right inside single CF layup for the aft/inboard exhaust pipe clearance bump, and a decent bit of cleanup done on that.  This of course being the final step for this bottom cowling clearance task as well.  The only requirement remaining is for a cross cowl stiffener that needs to be glassed in on the bottom cowl to complete all these niggling bottom cowl tasks.

I did actually buy some stuff, primarily for the wing light installs: I put in an order with ACS for a 24″ x 24″ sheet of 1/16″ plexiglass, cut in 6 each 8″ x 8″ pieces.  Concurrently I put in an order with McMaster-Carr for some hardware and the 3/8″ diameter 6061 aluminum rods that I’ll need for mounting the wing light assemblies into the wing leading edge pockets.

I then went downtown and picked up a cheaper toaster oven to heat up the wing light lenses.  Since acrylic off-gasses some nasty chemicals when it gets heated up, I didn’t want to work the wing light lenses in my kitchen stove.

Unfortunately, while I was out buying the toaster oven for creating the wing light lenses, that’s when FedEx stopped by to deliver the package containing the engine inner baffle forms.  I didn’t realize that I would need to sign for them, so I missed the delivery and won’t be getting them now until Monday (sigh).

I of course have a myriad of things that I can work on, and again, starting tomorrow I plan on jumping back onto the build whole-hog.

Chapter 23 – Final on clearance bump

I started off today by pulling the peel ply on the external 2-ply CF layup on the bottom cowling right side aft/inboard exhaust pipe clearance bump.  I then cleaned up the layup a bit.

I then pulled the taped-up cardboard and wood forms from the inside of the CF layup.  Here are couple of shots of the inside and outside of those forms.

I then pulled the interior peel ply off the 2-ply CF layup and cleaned all that up a good deal.

I then took a break for a few hours to head out for some face time with some Canardian buddies!

You see, last night while I was at Jess’s house for Thanksgiving dinner I got a call with both Mike Beasley and Marco C. on the line.  They both wanted to take a quick scoot in their planes and meet somewhere for lunch, and asked if I was available to meet them today at the New Bern airport.  Which I certainly made time for!  Jess and I met Mike and Marco at the airport and then we all headed downtown New Bern to walk around a bit and grab lunch.  It was great seeing those guys for a few hours before they both headed back home —in different directions: Mike south to Georgia and Marco north to Virginia (Thanks guys… good times!).

Back in the shop for a couple of hours I sanded down the bottom cowling edges around the right side aft/inboard exhaust pipe clearance bump opening with the cured 2-ply CF layup on the exterior side.  I cleaned up the fresh layup around the edges and ensured there was a good transition for an internal 1-ply CF layup, which I then knocked out next.

Another shot of the 1-ply CF layup on the interior of the bottom cowling right side aft/inboard exhaust pipe clearance bump.

I then peel plied the internal 1-ply CF layup.

I should be getting the engine inner baffle molds tomorrow and plan on starting in on those ASAP, although I will be heading back to New Bern tomorrow afternoon with Jess and some friends to watch an airshow and then out to dinner.  So most of tomorrow will be more social duties calling.  I do plan on getting back onto the build full bore from Sunday moving forward.

 

Chapter 23 – Right cowl “update”

Happy Thanksgiving everyone!  Yes, even those of you who don’t celebrate the holiday (you know who you are!).

Well, I am THANKFUL that I was able to get a significant task knocked out today: the initial layup on the lower cowling right side aft/inboard exhaust pipe clearance bump.  Again, this is the LAST of the clearance bumps, divots, channels, etc. that I plan on doing at this time, or see any further requirement for!

As I said in yesterday’s post, it was too late to make up a wood template/form last night, but that was the first and only thing on my list today —ok, and hot-gluing it into place— before heading over to Jess’s for a wonderful Thanksgiving feast! (All Keto too! Thanks Hon!).

I used my same Metal Brake crate for cutting out this form with my saber saw before then trimming and shaping each end a bit to allow it to fit snugly into place.  After I got it all situated, I then hot glued it into place.

Here’s a lower external cowl shot of the wood vertical “smile” form hot glued into place.

And me checking the original cardboard template against the hot glued in place wood form.

I then finalized the shape of the flatter, horizontal surface-taped cardboard form that I then hot-glued to the wood form’s bottom edge, and then taped into place everywhere else.

An outboard-in shot of the flatter, horizontal surface-taped cardboard form in place.

Again, in my haste the one thing I failed to take into account when making up the initial vertical cardboard “smile” template and subsequent wood form was the overlapping horizontal thin cardboard form on the bottom edge… that, and then add a couple of plies of tape and then even a ply of peel ply over that.  That all served to add a good 0.1″ depth to this clearance bumpout, which obviously was not as much as I was planning on.

Oh, well… moving forward.

I was on the phone with my son when I kicked off the actual layup and forgot to grab a shot after I had prepped the surrounding CF for layup and of the form taped up with gray duct tape.  Here it is after I wetted out the entire layup area and then added peel ply to both the vertical “smile” and curved horizontal parts of the exhaust pipe clearance bump.

I then laid up 2 plies of CF that I had cut previously (along with the pieces of peel ply).  Although a hair more pronounced than I was aiming for, the bump itself is looking pretty darn good (IMO).

I then of course peel pied the 2-ply CF layup.

And another shot of the peel plied 2-ply CF layup on the external bottom cowling right side aft/inboard exhaust pipe clearance bump.

I’ll also provide yet another reminder that for the sake of saving time and effort, I’m shamelessly copying Klaus Savier in his bottom cowling clearance bumps for his exhaust pipes.  I’m betting Klaus probably got this about as close to correct as you can get.

Now, that being said… I’ll note the beginning state of my bottom cowl surface is both significantly more sloping/angled inward (not horizontal as his is) and curved fore-aft where I placed my “swooshing smile” type bumpout.  The bottom line is I think my clearance is a bit more pronounced than his is due to the starting bottom cowl characteristics.

Nonetheless, the exhaust pipe bumpout that I just laid up should serve its purpose for providing needed clearance and that’s all that matters at this point!

Pressing forward….