Category: Baffles

Continued Prop and Spinner

May 29, 2020 – I addressed the issues surrounding the prop installation.

There were gaps between the spinner inner surfaces and the spinner back and front plates. This would show itself when I tightened the screws and the spinner would press in. This would cause cracking paint at the very least.

The drawings say to build up fiberglass at the mating surfaces inside the spinner. So I taped off the surfaces so I could get the spinner back off afterwards.

I slathered a resin mixture with flox inside the spinner cone at those locations and installed the spinner, tightening the screws to the point where they were tight but not pressing in.

After it was cured, I had some fun getting the spinner off, but it did come off. I sanded as much excess material out of there as I dared. It’s kind of ugly inside, but it worked. The gaps are filled.

After that, we pulled the prop back off so I could address the issues I found when we first installed the prop.

The ramp for the baffle on the right side was hitting the flywheel. I removed about 1/2″ from that leading edge.

I also turned the main alternator bolt around so the nut faces forward. I found out that with the bolt head facing forward, it couldn’t be pulled out all the way if I had to replace the alternator.

We reinstalled the prop.

I bought the Anti-Splat prop wrench to torque the prop.

After I torqued it all I safetied the prop. I used little pieces of nylon tubing to protect the parts of the flange where the safety wire would cross over.

Time: 5:20

Prop and Spinner

April 10, 2020 – I continued with the spinner.

I made the cutouts for the prop blades using the template I got from Hartzell.

I laid out the screw holes and drilled them through the backplate.

The holes in the front plate are already piloted. I could faintly see them through the fiberglass, so I carefully drilled to match.

I installed the nutplates.

I temporarily installed the spinner onto the prop so I could make the filler plates that go behind the blades.

Using the template as a guide, I trimmed the fillers to more or less fit the spinner cutouts., then made the attach plates.

I riveted the fillers in place. This came out really nice.

It was time to install the prop, potentially for good. I had to install the nutplates in the inlets.

We came to realize that we needed the cowl off to install the prop.

A couple of good friends at Aerocountry came by and we wrestled the prop into place. Not a bad job, but tedious. We lubed the o-ring and the crankshaft attach point, then lifted the prop up and slowly tightened the bolts.

Once the prop was installed (not safetied), I took a look around. Probably the biggest problem I found was that the flywheel was hitting the right inlet ramp baffle. In fact as we tightened the prop bolts, it pressed the flywheel into the ramp.

The only other obvious issue I found was that the bolt for the alternator could not be fully removed. It hits the flywheel. So I will turn that bolt around when I take the prop back off.

I came back the next day to try to install the cowls. Kind of a pain, but I did get the lower cowl on. With the seals and the inlet ramps, I have to put the front of the cowl up first, kind of hook it into place, then swing the aft edge up and fasten it. Well, the baffle seal attached to the right inlet would not go up above the ramp. The seal lies under the ramp. I really don’t see a problem with this. In fact, a friend’s RV-8 has the inlet seals under the ramps. So I’ll live with it.

This was a moment I’d been waiting for ever since I installed the Skybolt fasteners. I was afraid maybe the cowl moved as I was installing the fasteners. Well, it all looks good. I like the gap between the prop and the cowl, and it is fairly well centered on the cowl.

Here it is with the spinner on. Pretty awesome…

I’m planning now to finish up all the tail fairings, then I’ll come back, remove the cowls and the prop, fix the issues I’ve found, then probably install the prop for good.

Time: 10:15

Inlet ramp modification

January 16, 2020 – I decided I didn’t like the setup I had for the left inlet and how it contacts the cowl.

In another post I described the issue I had with the leading edge of the inlet ramp and how I solved it. Here’s a picture:

I decided to cut off that leading edge and make a bracket that would secure the front of the air filter.

Here’s the cut:

I bent a bracket that attaches to the snorkel, and holds the air filter. I riveted it in place using pop rivets.

It’s all covered by the seal on the lower cowl.

Time: 1:00

Baffle Rods

December 21, 2019 – I made the baffle rods that secure the baffles beneath the engine.

The rods are cut to length, then bent to clear underneath the cylinders. They are hard to photograph when in position, but you can see my marks where to bend them…

Then the ends get threaded for 6-32 nuts.

You are given plastic tubing to protect areas where the rods may touch. This is a very tight fit, but I used a trick to fit the brake line fittings way back when… I boiled soapy water and heated the plastic then, slowly pulled the tubing onto the rods. Worked great, but got a blister anyway in the process.

Here’s a rod ready to be installed:

And actually a decent picture of two of the rods installed:

Time: 3:55

Mounted Oil Cooler

December 4, 2019 – I reinforced the baffle and mounted the oil cooler.

I originally had a piece of aluminum angle that I was going to use to reinforce the baffle where the oil cooler mounts. I never really liked it and didn’t think it would last very long. I happened on a nice piece of thin titanium. Easy to bend and work with. Drilling is the hard part, but if you take your time and use Boelube, it’s easy.

Here’s the angle installed:

I reinstalled the baffle and started working on the cooler itself.

I had previously clocked the fittings for the oil lines in and out. I marked them and installed them permanently.

I then installed the cooler.

I secured the oil lines at both ends. I’ll have to clamp everything later on, but for now they are in.

Time: 5:30

Continued Baffles and Seals

December 4, 2019 – After I installed the ramps in the top cowl, I git myself caught up with where I should have been. This is in no particular order…

I needed to close the ends of the ramps so air would not escape to the area outside of the baffles. I carved insulation foam to fit the inboard ends of the ramps, then taped them with packing tape and laid up a couple of layers of cloth over those.

I clecoed them and glued (resined?) them in place. They’re not the finest example of fiberglass work, but they are invisible on the airplane.

I cut the left and right side baffles to fit the ramps, then used the paper clip trick again to find the correct final dimension to allow for the seals.

I used manila paper to make templates for the seals around the ramps. These seals fit surprisingly well here…

I installed the inlet seals on the lower cowl. Since the #6 screws blew right through the fiberglass, I used #8 screws instead.


In taking the cowlings on and off, I found another problem. Due to my design of the left inlet ramp and the air filter, the cowl interferes with the ramp. The screws for the inlet seals that attach to the cowl hit the very leading edge of the ramp. A side result of this interference is that I got my first baffle crack even without running the engine…  🙁

I just cut off the corner of that ramp using the crack as one of the edges of the cut. I also notched the inlet ramp to fit the attaching nuts for the seal on the lower cowl.

Here’s the end result (hard to get the camera in there):

I was having a hard time trying to figure out the baffle seals around the front (behind the prop spinner). I looked at a friend’s airplane, and because of the closed ends of the upper cowl ramps, he had minimal sealage there. So I just placed short flat pieces of seal that guide the air past the inlet.

Once all of this was done, I decided it was time to permanently install the seals. After all the hassle of fitting everything, this was mindless. In order to keep each baffle separate and removable, I used screws on the side baffles between the forward and aft sections. The seals overlap at that one point. So this way if I have to remove just one baffle, I don’t have to drill out any rivets.

So now I’ll call the baffle seals complete, except for filling any gaps with RTV.

Time 19:21

Baffle Seals

October 16, 2019 – I continued to cut and fit seals for the baffle, and I ran into an issue.

I started cutting the baffle seals. Started with the sides, since they are easy and I can learn the tricks.

The back is pretty straight-forward as well.

I decided to tie the two seals together using the top bolt of the center bracket. Then I trimmed the seals to go around that bracket.

I started the seals around the front baffles that go behind the spinner.

I cut small pieces that will start down the sides on the front baffles.

I took off the lower cowl to do the small seals that seal the lower edges of the inlets to the ramps. I made the retaining strips.

I made the seal strips and started to install them with the retainers per the instructions, using #6 countersunk screws. Well, I pulled a screw right through the fiberglass of the cowl.

So I’ll plan on using small #8 button head screws here.

I went to look at a friend’s inlet seals on his RV-8, and he mentioned a problem he was having getting his upper inlet ramps to seal properly. Ooops. I realized that I hadn’t even installed these ramps on the upper cowl. I somehow thought these might be optional. My DAR told me they were absolutely necessary especially in climb, to smooth the airflow in and over the engine.

I knew I had these ramps, so I took them off the shelf, figured out where and how they fit, and epoxied them into place. I used clecoes to hold them. These holes can easily be filled later.

I’ll go back and trim these ramps to fit, and I’ll have to trim my baffles again to fit the top cowl.

Time: 5:10

Continued Baffles and various Firewall Forward items

October 10, 2019 – Because the baffles can block access to some items, and there’s a lot of items that are dependent on other items being installed, I’m installing several items along with the baffles.

The prop oil line passes through the right front ramp, so I needed to install that. What a pain. The grommet fits, but the ramp stack-up is pretty thick, and the grommet is really hard to get into place.

Here’s the view from above and below.

I also installed the oil dipstick tube.

I wanted to check the routing of the tubes for the oil cooler, so I temp installed the cooler and loosely routed the oil lines in and out. Nothing here is permanently installed yet.

After painting the inlet on the left side, I temp installed it. The way I’ve done this, the snorkel and the baffle are a single assembly. It’s kind of a pain, but it can be installed and removed as a unit. The one issue is that the forward left baffle that goes up behind the spinner needs to be installed separately. So I’m using screws and nuts here.

I just started on the baffle seals, but no picture yet. That’ll be next time.

Time: 15:00

Baffles Assembly

September 27, 2019 – I am continuing to assemble the baffles.

The pictures I seem to have right now are for the left rear baffle, including the provision for the oil cooler.

Back when I started the baffles, the instructions have you go ahead and cut out the hole for the oil cooler. That’s misleading; you really can’t / shouldn’t do that until everything is fitted with the cowling.

The oil cooler support brace is pre-drilled, and the holes need to line up with the doubler for the cooler. The trick is locating these two pieces together, since they are on opposite sides of the baffle. There are also flanges on the sides of this brace, that are pre-drilled, but shouldn’t be. These holes are useless, since the brace needs to be located up or down depending on where you can fit the cooler, and the top of this brace gets a pretty radical trim to fit the upper cowl. So I ignored those holes and drilled my own where it made sense.

You can see in a couple of these how high this brace is in relation to the top of the trimmed baffle. I based the location of the cooler on the ability to use some of the side flanges in the brace for some support. I wanted the cooler as high as possible. There is no interference here, and I don’t even have to trim the flange of the cooler to clear the engine mount, like some people have had to.

I needed to make sure the rivets and fasteners in this area cleared the cylinder. One place I thought was interesting was the inboard vertical line of fasteners for the doubler. The flush heads of the rivets need to face the cooler, which puts the rivet shop heads against the cylinder. The holes line up perfectly between cooling fins on the cylinder.

I assembled this baffle as needed. I didn’t install any fasteners on the outboard vertical flange, since this may get an additional support angle to help prevent cracking later on.

Here’s the baffle in place.

I also made the cutout for the ignition lead seal, and I drilled a hole for the cooling blast tube for the mag.

I’m just working my way around the engine, polishing cut edges and assembling the baffles as needed. I’m also drilling holes for other items, like the fuel line which comes from the Red Cube up to the flow divider. This fuel line will pass through the right rear baffle. I think I’m going to “permanently” install the baffles before I do the seals.

Time: 8:00

Trimmed baffle tops to fit cowl

September 20, 2019 – I got the tops of the baffles trimmed to where the top cowl can be installed, plus gave room for the seals.

I went to the aircraft section of Kroger and bought paper clips. This is a trick I’ve read about in the RV community. In fact, at lunch today I was talking to a guy who was doing baffles on a different type of airplane, and I mentioned the paper clips. He was amazed…  By the way, for the record I bought 120 clips.

I placed them around the baffles, high enough that I knew they would make contact.

I set the upper cowl in place, and removed it again. This gave me the initial clearance.

The one big conflict I had was at the aft left corner above where the oil cooler will be. I ground a radius there, reset the clips, and verified everything by doing it all again.

The instructions for the baffles call for a 3/8″ – 1/2″ gap to allow for the seals. I measured and marked 1/2″ from the top of each clip.

This gave me my cut line all the way around.

After the cuts, I reset all the clips and verified the cuts.

I removed my FOD protection and looked everything over. I just have to clean up and deburr the cut lines. I’ll do that on each baffle individually.

I made and attached the small clips that secure the forward and aft side baffles to each other.

I also made the cutout for the right side plug wires. This cutout is for the top wires that pass through the rear baffle.

That brought me to a good place to stop for the day.

Time: 6:00

Assembled Left Inlet

September 13, 2019 – I assembled the left inlet including the air filter and snorkel.

I needed to know if the entire left forward baffles, ramp, and snorkel could be removed and installed as a unit, because of how I built it. Well, here it is:

While it was off, I needed to mod the snorkel down where the lower starter lug just touches it.

I just drilled a 1″ hole, and did a layup over that. Pushed the cloth down a little bit with my thumb to make a nice little divot.

I riveted the parts for this assembly.

Here’s the air filter installed with the retaining ring:

In the last post I mentioned how I bent the front side baffles to wrap under the ramps on both sides. I didn’t have good edge distance for the fasteners incorporating the air filter, so I cut that flange off of the left side baffle.

I temporarily installed this assembly back on the engine, and got ready to have everything in place to start trimming the tops of the baffles.

Here’s a couple of overview shots of the front baffles:

I wanted to protect the engine and accessories from the inevitable metal shavings from trimming the baffles to I did a little bit of FOD protection.

I put the top cowl in place. The baffles are tall and hold the top cowl off, so the tops of the baffles need to be trimmed, also allowing for about 3/8″ – 1/2″ for the baffle seal.

The front baffles appear to be the tallest, so I started with them. With the top cowl resting in place, I reached through and marked the baffles for cutting.

I cut this line and put the cowl back on. It’s getting there. I’ll work my way around the baffles so the cowl just drops into place evenly.

Time: 8:10

Forward Baffles

September 5, 2019 – The never-ending chapter of the baffles continues.

I placed the forward baffles in position. I made the clips that attach these at the bottom onto the left and right inlet ramps.

Looking at these pictures, one question comes to mind. I’m not sure if these baffles need to be trimmed where they go just inboard of the cowl inlet lip, where the cleco clamps are placed. I can’t find any pictures that show this area specifically. It kind of makes sense to me to leave that part there, and run the screws through that. It would only serve to seal that area that much more. Oh well, I’ll figure that out…

Anyway, I drilled the three clips.

One thing I don’t appear to have a picture of is the left ramp support bracket. This bracket attaches to the case just above the starter, and supports the inboard forward end of the left inlet ramp. The way I interpret this, the top holes need to be drilled through the ramp.

They would interfere with the CB-702Q bracket which is on the aft side of the left forward baffle. So I figured out where both of these parts intersect above and below the ramp. This picture shows the area where the support bracket lies under the ramp, and the fastener with the cleco is the common fastener.

I riveted these clips to the forward baffles.

Now I had to deal with the side baffles where they meet the inlet ramps on both sides. The bottom edges of these baffles are supposed to be bent.

Here’s the right side:

And the left:

I thought about just cutting the left side off since I had changes the basic structure with the snorkel, but I decided to incorporate that into the structure.

Here’s the right side after the bend. It looks really bad in this photo, but it really does fit nicely.

…and the left side. I bent it then cut it to fit in the channel where the snorkel attaches. It will be attached when I do the fasteners for the snorkel and filter retainer.

The plans call for a conical gusset on each side to smooth airflow into the baffles. Since the left side has the air filter and its associated structure. I don’t need one there. I made a rough one for the right side. It needs to be cleaned up, but I like it. They call for it to be made from .032″, but I wonder if .025″ would be adequate. It fits the contour of the cowl inlet.

This was one of those days where you get a lot done, but nothing looks different…

Time: 6:50

Air Filter Fitted

August 29, 2019 – I have the air filter fitted to the snorkel.

In the last update, I had fitted and drilled the filter retainer brackets to the snorkel. This time around, I enlarged the square hole in the inlet ramp to allow the filter to drop in.

I riveted the angles to the snorkel as required.

One mistake I made was to trim all four edges of the hole in the ramp, but the intent is for the filter to slide under the forward lip, then have retainers on the inboard and outboard sides. I also didn’t like that stock setup for retaining the filter, since I had a very small margin on the outboard edge, plus I needed to install an angle to connect the ramp and the vertical baffle. So I decided to make a doubler that went all the way around the filter hole, and incorporated the angle for the vertical baffle.

Then I made a retainer that secures the filter on 3 sides, and the filter slides under the doubler on the forward edge.

I drilled rivet holes for the doubler, then drilled screw holes for the top retainer. I bent the edges of the retainer down so they would slightly contact the filter.

I test fit the filter. Looks great. The bent edges even just touch the rubber seal around the filter element.

I made the original retainer out of .025″, but I decided to make another one out of .032″. It’s a bit more sturdy.

I bent the aft retaining angle that is attached to the snorkel, since it rests under the baffle behind the snorkel.

I’m happy with how this fits. I just need to install the nutplates and rivets as required to put this thing together.

One other thing I did was to trim the left inlet ramp support bracket that goes inboard of the snorkel. I trimmed about 5/8″ from the supplied plate. It seems to fit nicely, but I’m going to wait to do any more until I fit the baffles that go up in front behind the spinner and flywheel.

Time: 9:00

Inlet snorkel and ramp

August 12, 2019 – Didn’t do all of this work in one day. Had a trip to a little town in Wisconsin somewhere in there…

The drama with the inlet ramp continues…

First I made sure the snorkel is located where it’s going to be. I ended up using a hole duplicator to drill the holes in the snorkel at the fuel servo. A #10 hole finder fits perfectly on the threads of the servo. Then I used the blanking plate that was on the servo to take the holes up to 1/4″.

Here’s the snorkel in place. I have read about a lot of interference with other items, especially the lugs on the starter. I have one lug that just touches. When everything else here is done I think I’ll just cut away a little bit of the snorkel and glass a flat piece right there. I don’t really want to grind part of the starter case.

Now I have my second inlet ramp. I trimmed the side like the first on, and left a lot of material on the front, just so it fits in the cowl.

Now the snorkel is just to the outboard edge of the ramp…

I have the vertical section of the baffle in line with the edge of the cowl lip per the instructions.

It makes sense to me that if I move that piece outboard into the middle of the cowl lip, it shouldn’t matter. As long as that gap is sealed later on…

So I ordered inlet ramp #3…

When it arrived I trimmed it less than I did ramp #2. Much better.

I moved on and marked and trimmed the hole for the air filter.

I started fitting the filter support brackets and drilled them to the snorkel and structure as needed. Here’s the aft one. It fits nicely under the baffle behind the snorkel.

I had to trim each piece even from the original dimensions given in the instructions. But I like where this is going.

The next step is to enlarge the hole in the ramp so the filter fits down inside the retainers and flush with the ramp.

Time: 10:10

More baffles and inlet snorkel

July 9, 2019 – I continued with the inlet ramps for the baffles.

Per the instructions, I continued trimming the inlet ramps to fit the lower cowl.

The forward edges of each ramp are trimmed to cleanly meet the edge of the cowl inlets. But you can see that the angle is different between the ramps and the cowl inlet. So they call for a diagonal bend across the ramps to align the forward edge with the cowl inlets.

I was concerned about this bend on the left side, because the air filter and snorkel for the air inlet will be there. After some research, I decided to go ahead and fit the ramp, then essentially modify it for the air filter.

OK, big note here… if you are installing the snorkel inlet, DON’T trim the forward edge of the ramp. The instructions for the baffles don’t allow for this possibility, but the instructions for the snorkel do. Maybe I should have read ahead.

Here are pictures of the diagonal bends. You can see how nicely they line up with the cowl edges now.

I decided to go ahead and fit the snorkel before continuing with the rest of the baffles.

I temporarily installed the alternator because I’d read about conflicts between the snorkel and other parts of the engine.

No issues with the alternator. There is slight interference between a lower mounting lug on the starter and the snorkel. I’ve seen where people totally removed this or both of these lower lugs. I may not have to do that.

My bigger issue right now is that the forward face of the snorkel is even with the cut edge of the inlet ramp.

Hence my note above about not trimming this edge of the ramp quite so far.

So I ordered another inlet ramp from Van’s.

Time: 5:10

Replaced prop oil line

June 25, 2019 – I decided to replace the prop oil line with a steel tube.

I didn’t like the mess that the right inlet ramp was becoming, so I took a step backwards.

I decided to order the steel tube for the prop oil line that is recommended. I found the Lycoming parts manual for the IO-360-M1B and ordered the tube and associated parts from Air Power in Arlington. Had to call them with a question and they were very helpful. The tube part number is 75167 and it works with the Superior cold air sump. I also ordered the replacement baffle parts from Van’s.

With parts in hand I tried to thread the oil tube into place. Kind of a puzzle, but I held my tongue just right and it went into place. I had to turn the fittings on each end just a bit, but here it is:

BTW, I never was able to find a good picture online, so you’re welcome… I still have to secure it in place permanently, but this will work for the baffle work.

I worked on the replacement baffle pieces and got to where I needed to be last week.

With the 1″ hole for the oil line, things are looking much better.

Now I’m ready to start fitting the cowls with the baffling.

Time: 1:30

Continued Baffles

June 13, 2019 – More baffling work…

I retrieved my firewall sealant from the house, and sealed and installed the scat tube connection. Here’s the baffle for #3 in place, and a close up of the bracket that secures it to the case.

I secured the #4 baffle in place as well, since these two will tie together.

#4 is also secured to the case with a bolt and a spacer.

I put together #2. It was pretty straightforward.

Guess I didn’t get a picture of the side baffle for #1. But it does get a special doubler made. made general cuts per the drawing, but it’s easiest just to cleco it to the baffle plate and sand to fit from there.

There is a bracket that mounts on top of the engine for the rear baffles. The fuel line for #4 was in the way. I just disconnected it from the manifold, turned the clamp around and adjusted a bend or two. It works great.

There is also a bracket that mounts at the front.

Here’s everything so far:

Then I started on the inlet ramp for #1. There are several pieces for this.

The oil line for the prop will pass through this baffle. You are supposed to drill a hole for it. Here’s the first real issue I’ve had with the baffles so far. The kit includes a grommet for a steel oil line to the prop, so the hole needs to be 1″. I have a flexible tube for the oil line, and the part that will pass through the baffle is 1″ in diameter. OK. We’ll see what happens. I drilled a 1″ hole to start with.

I had to enlarge the hole outboard because the oil line comes up through the baffle at an angle.

The oil line will not allow the baffle to lie in position to secure the bracket.

So I decided to remove material so that the oil line will pass through, connect without cross-threading, and the baffle will lie in the correct position. It’s pretty ugly, and I’ve lost two rivet locations, but I think I can relocate them. I just have very little edge distance on the top angle forward of that hole. I’m going to consult some people smarter than I, and see what develops here.

The ramp also interferes with the flywheel, but I believe that will not be a factor after the ramp is fit to the lower cowl.

I did the left side inlet ramp. No issues that compare to the right side.

So here’s where we stand. The next step is fitting the ramps to the lower cowl.

Time: 7:30

Baffles, continued

January 24, 2019 – I continued with the baffles.

I riveted the small doublers on the baffle for #4 cylinder, then went to fit the baffle. It fits tightly around the rocker box cover and it needed trimming so attach holes would line up.


I then located where I thought the oil cooler would mount. One detail on the plans sheet shows a reference 3/8″ margin from the edge of the oil cooler doubler to the edge of the baffle. So I located it there and back-drilled the holes from the doubler to the baffle. Then I removed the material in the baffle where the oil cooler would go.

All well and good…

Then there’s an oil cooler brace that has prepunched holes. Two issues…the holes are prepunched to #40; that’s fine, but the holes in the doubler that this brace matches up to are #30. Worse still, as I had everything located, these holes don’t line up.

Put the question out to the experts on and learned two things. One was that I should wait to locate the oil cooler until the baffles are situated, the other was that maybe the doubler needed to be just 1/4″ from the edge of the baffle. That would make these holes line up. I’m less worried about the disparity between #40 and #30 holes; I’ll probably go ahead and make the rivets larger at that location.

I ordered a new CB-705A, which is the baffle with the oil cooler hole in it. I didn’t drill any other part yet…

There have also been huge issues with cracking at this location due to the weight of the oil cooler and vibration. I’ll be modding this area as almost everybody does. More on that later…

Time: 2:35