The last section is the forward baffles which are comprised of two pieces, the and right. These go right behind the propellor area and seal the area where the crank shaft comes through the cowl. I first clamped them together in place to see how much trimming would be needed. They also have two angles in them that try to match the ramps.
I worked the right side first and trimmed a little at time on the bottom until I had a perfect fit on the bottom and the curved portion of the engine case. Then I started on the left side. It’s hard to see in the above photo but the fit around the engine case is really bad, almost 3/4″ in spots. After looking this over Glenn suggested that I redrill the hole Vans punched for the bolt in the center top over to slide the baffle over and closer to the engine case. This would mean that I would have to tweak the angles of the side a little bit not much. So I did some measuring and came up with a good spot to drill the new hole making sure I would have edge distance for the new hole when I cut the new inboard edge.
Once I had the hole drilled I had to trim the bottom like the other side as well as the lower part of the center where the two halves come together.
This worked great and the gap is much better and will be sealed up with RTV later. So I started working on the bends of the sides to make them fit well. These eventually get tabs made out of angle that will tie the sides to the ramps. I made the clips and match drilled them to the sides and ramps.
On the left side I had to trim the tab a little to get it to sit good with the filter cover I made.
Now that the forward baffles were fit I moved to the right side conical gusset. This is a curved sheet in that ties the ramp to the lower cowl shape. It starts like a cone, small at the top of the ramp and gets wider at the bottom. This was a fun piece to make and took a while to get perfect. I started with a card stock template and transferred it to the sheet of aluminum.
After cutting it out I used the hand seamer and my rivet gun to shape the sheet into the shape I needed.
The shape needed tweaking a little but ended up perfect. I clamped it in place and match drilled the holes I laid out.
The left side can’t have one as the filter is in the way.
Next up will be to rivet some of these parts together, some will wait until final assembly. Then I will work on the bottom ties of the baffles. All this work leading up to the tough job of trimming the tops of the baffles to match the upper cowl.
Another modification I’m doing to my RV is to move the oil filter from the stock left side of the rear baffles to the right side on the engine mount. This allows for a much larger cooler to help with cooling my larger HP engine. To get the air from the engine area to the cooler is via a hole cut into the right side aft baffle and a fiberglass plenum. The cooler gets mounted to the engine mount via a two piece bracket and locks the cooler into a specific spot based on the geometry of the engine mount. I had the cooler temporary mounted to the brackets and used it with the plenum to get the initial cut line after I trimmed the side of the plenum to fit the cooler.
I returned the rear baffle and worked the plenum until I had a rough 1/4″ gap, this will get sealed with a rubber gasket eventually. To cut the aft side of the baffle ShowPlanes gives you a doubler with the hole steady cut into it. Unfortunately the hole in their doubler was too high for my plenum, not sure why but not a big deal…I’ll just make a new one.
The fit was perfect so I laid out a rivet line at the top, left and bottom. The right side could be match drilled to the baffle rivets.
After I had all the holes drilled and deburred I removed the material from the baffle.
After I was happy with all the edges on the inside I trimmed the top, bottom and right sides to make a nice fit. I dimpled all the common holes between the doubler and baffle. I also primed the surface of the double and riveted the holes except the row that are common to the side baffle as those will get done later.
This was one of those items that works in conjunction with the baffles that needed to get done while working on them.
I repeated the process of bending the left inlet ramp just like the right side to get the forward edge to sit nicely under the cowl lip. Once that was done I trimmed the outboard edge of the ramp to allow the side baffle to bend in as well. Once I was satisfied with the fit I bent the lower portion of the side baffle just like the right side baffle. No pictures of any of these steps as they look just like the right side. One thing I did different than the right side is I didn’t trim or did as little as possible the forward length of the side or ramp baffles. I read ahead on others build sites to realize that you can cut yourself short if you are using a horizontal induction system, which I am. Using the horizontal versus vertical means that I will have no “scoop” on the bottom of my cowl, instead my fuel injection system will get its air from a filter and fiberglass tube, called the snorkel, mounted on the left inlet ramp. So this was my next task to get this monster to fit properly and build out the filter bracket. First up was to create a temporary attachment to the fuel servo. Eventually the snorkel will get help in place with four bolts but for now you don’t know it’s exact position in order to drill those holes. I wanted to be able to rotate the snorkel about its center on the servo. So I cut a piece of scrape sheet and drilled out four matching holes for the servo. From those holes I measured diagonally across all four to come up with the very center of that sheet. I also created a 3/4″ thick wood circle exactly 2 3/8″ across, the same as the opening on the servo side of the snorkel. I drilled a hole in the center of the sheet for a small wood screw that would hole the wood in place dead center. I trimmed the sheet to be more square and fit the area a little better as well.
Now I could bolt the plate/wood to the servo and have a pivot point for the snorkel to rotate about and keep it centered on the servo.
Not thinking about thickness of the bolt heads I dint like how far away from the servo they kept the snorkel flange. So I replaced them with several small zip ties which reduced the gap.
Ok so now I rotated the snorkel around to try its position and see where I would have any clearance issues. The only spot was right at an accessory lug on the SkyTec started. I did a little research on line before this and read about this issue. SkyTec allows for these lugs to be removed if not needed in there paperwork as long as you leave an 1/8″. So I could remove the unwanted lug or redo some fiberglass…our came The hacksaw! With that removed I rotated the snorkel up until it hit the underside of the left ramp. From there I outlined with a sharpie the shape of the top of the snorkel.
Using my drill, jigsaw, file and sandpaper I was able to remove this material to get the initial rough opening. I put everything back in place to see how it looked as I rotated the snorkel into place.
The fit in location was perfect, this hole will end up getting opened up to allow for a 3/8″ gap around the snorkel for the air filter. The snorkel will also get cut to give it a 3/8″ gap under the ramp. For now this position will allow me to drill for the four bolts that will hold the snorkel in place on the servo. So using a flashlight and a careful drill bit I drilled the center of the four holes enlarging them enough to allow for the 1/4″ bolts.
So now I could start to careful trimming of the top of the snorkel to give me that gap I needed.
To hold the air filter in place vans gives you bracket material that has a 3/8″ ledge for the filter to sit into. These brackets sit inside the snorkel and under the ramp. The plans for these are hand drawn and very confusing. I started with the aft section and trimmed the bracket to fit inside the snorkel and up under the aft section of the ramp. Once in place with some clamps I match drilled the holes for now. These will get screws eventually so the snorkel can be removed. I also drilled five holes through the bracket and the fiberglass of the snorkel. These holes will be used to rivet the bracket in place.
From there I moved to the two side brackets starting with the outboard one. I drilled for the five holes in the fiberglass to see how much material I would be working with for the screw holes up into the ramp, this is where I had to grime material to get the side baffle close to the cowl lip. I had enough space for regular #8 screw nutplates but not for countersunk #8 nutplates. That just means that these three screws will not be countersunk on the top, not a big deal at all.
The inboard bracket I’m going to wait to drill the screw holes until I have the baffles behind the ring gear done as they have a couple pieces of angle support that could be in the way. That way I can work through those issues at the same time as I install those baffles. I did drill the five holes into the fiberglass for that inboard bracket to hold it in place.
I removed all the parts so I could open up the hole to allow the filter to drop in and sit on the ledge of the brackets I installed. Again I used various tools, the band saw and sand paper to get the opening just right. The small amount that would remain on the forward edge of the ramp wouldn’t be of any use so I decided to cut it out. This area will be covered with the baffle seal material when it’s all done.
The bent edge of the side baffle is too long so I needed to trim it as well.
After the areas were fine tuned I installed the snorkel to see how it fit with the new opening. I was very happy with the fit and how it turned out.
The two aft corners will get sealed up to prevent air leaking. I grabbed the filter to see how it fit in place.
There are all kinds of ways to secure the filter so it doesn’t move, Vans gives you two small parts to hold the left and right side but I didn’t like how they fit or looked. So I decided that I would create a solid piece of .032″ sheet that would frame the top of the filter. It would be held down with six screws, two on each side. I also will put a 90° bend down on the forward edge to keep the filter from moving forward. I started with the solid sheet and aligned all the edges to get a perfect fit. I installed the lower cowl to see how it fit in place as well.
Once I had the overall fit perfect I measured for the center cut out and marked it to cut.
After I rough cut the hole with my Dremel cut off wheel I used a file to straighten all the edges. I used sandpaper to clean all edges up and smooth out the file marks. I used my break to bend down the forward edge after making a couple cuts to create a “tab” on the forward edge.
This makes for easy access to the filter when it needs cleaning or replacement.
Before I could move to the next step I needed to get all four sections that go around the chrome valve covers to fit just right. They come with the basic Lycoming shape but need to be trimmed to fit. There are two holes on each section so I decided on a plan of attack. I worked one section at a time and repeated the process for the rest. I slid the baffle down until the screw holes, which were off a little, were equal on both sides. Then using a red Sharpie I traced the valve cover. I removed the baffle and sanded down until touching the red Sharpie line using my drum sanding bit in the Dremel. I returned the baffle and checked the fit, repeating this process until I had the holes matching the holes in the engine and a 1/16″ reveal around the valve cover.
I cleaned and deburred the forward and aft top baffle bracket. These use the engine case bolts to hold them in place. I attached them, temporarily and not torqued yet, so that I can get all the work done before painting them.
The plans now call for you to work the forward inlet baffles. I started with the right side and cleckoed/match drilled all the holes.
In the right side I need to account the constant speed propellor oil line. This line runs from the front of the engine case to the propeller governor in the aft section. I need to drill a 1″ hole that will get a rubber grommet later. I used the drill press and step bit to drill through both parts at the same time.
I took all the parts apart and deburred the holes/edges. I prepped and primed the lower strip of the air dam that gets riveted now. Once the primer was dry I riveted it in place and reclecko’d all the parts back together. I took the baffle assembly and put in place which took a couple of try’s as the lower bracket needed trimming to fit around the cylinder.
from this point you have to start working the forward inlet ramps of the baffles to match and fit the lower part of your engine cowling. The ramps have an angle to them which is short for bringing the ramp up to the cowl lip. The goal is to bring the ramp up to the lip leaving a 1/16 inch gap. Here you can see the gap that you start with, it’s quite large.
So the process that I used was to remove the cowl, remove the screws holding the baffle in place, remove the baffle, slightly bend the ramp upward, return the baffle to the engine, screw it in place, return the cowl and check the gap. This process is time-consuming but necessary so that I don’t bend it too much. I started with the right side first and get the process multiple times to get it right.
You can see that last photo the inboard edge of the ramp is perfect however the outboard edge still has a gap. This is due to the angle of the inlet on the fiberglass. To solve that issue Vans has you mark a point at the where the inboard section touches the inlet, the tangent, and draw a line between it and a point on the outboard aft corner of the ramp. This line now becomes a reference line at which you can bend the ramp to bring up the outboard edge to the cowl lip. I used a few boards and clamps to make this bend. I did this a few times to get the bend right.
Now that the ramp is in position I need to work on the side baffle that meets up to that ramp. This also needs to be brought up to within a 1/16 inch gap of the vertical portion of the cowl lip. Again it’s the same process of mark, remove everything, remove some material and then return to see how it looks.
A lot of material has to be removed from these battles, including the forward edge of the ramp. I marked the edge of the fiberglass onto the ramp to give me a start line. This also gives me a reference point to create the bottom bend on the side baffle that will hold and support the ramp.
I then marked out a tab on the side baffle that would get bent 90° to create the support for the ramp.
Once I was happy with my layout I made the cuts and bent the tab using some boards and my rivet gun with the flush head using low power.
I fine tuned it with my hand seamer. I returned it in place to check the fit followed by trimming the forward edge of the ramp. I used a clamp to hold the corner together and returned the cowl to see how it looked.
Next up the left side ramp which houses the air filter and “snorkel” attaching the fuel/air servo.
To get an accurate fuel flow reading on my Dynon system I needed to convert actual fuel flowing to a digital signal. To do this I’m using the “Red Cube” transducer which will take care of this task. My way better half, Tricia, got this for me for Christmas! This girl knows the way to my heart…airplane parts! There are as many ideas as where to mount this as there are primer wars. I decided to follow Jason Beavers location and just put it just to the side of the fuel servo with a short fuel line. From the cube the fuel line will run vertically to the fuel divider “spider”. To start I needed to remove the lower cylinder baffle the AeroSport power installed as well as the oil return line so I could get the baffle out.
I will need to drill a hole in this baffle and place a grommet so the fuel line can pass through it. With the help of Glenn I measured the two lines, one from the servo to the cube and one from the cube to the spider. I’m using a couple aluminum fittings for the mock up and will put in stainless steal fittings when I assemble them.
I ordered the two lines from TSFlightlines, Tom is a great guy and answered every question instantly via email. They arrived just a couple days later and looked great. I really like how he uses a very tight fire sleeve which makes the line look great without a sloppy look. I first measured where I wanted the grommet and drilled the 7/8″ hole. I picked up some high temp grommets from McMaster Carr with the dimensions of 7/8″ for the drilled hole, 5/8″ for the center of the grommet and 1/16″ gap for the thickness. I drilled the hole with the step bit and cleaned up the edges and put the grommet in place. I then reattached the baffle retention bracket on the top of the cylinders after returning the baffle back between the cylinders. Darren at AeroSport showed me a trick to get this back in place. I used some safety wire around the hook. I pulled the wire up through the slot in the bracket and clamped my safety wire pliers on to it. This gave me a lead to pull the hook up with. Then I used a spade drill bit loaded into my adjustable screw driver and pushed down on the bracket while pulling up with the safety wire. Works like a charm!
I grabbed the first line and connected it to the servos elbow. I then screwed in the stainless steel nipple and elbow into the cube and connected it to the line going to the servo.
I then ran the second longer line down through the cylinders and the grommet connecting it to the spider elbow and the cube elbow. To help secure the cube I decided to use some .063″ thick aluminum to make a bracket. The forward spinner support, that I was planning on using, I used a piece of card stock to mock up this bracket. Then I transferred it to the aluminum and cut it out.
I drilled a hole to account for the wiring and match drilled the mounting holes. I don’t have the right length, AN4-17A, bolts so I used longer ones with a set of washers. This allowed me to make sure the bracket is good and I’ll order the correct bolts later.
I connected the hoses to the cube so I could mark the bolt hole from the sump. I took a the end of the bolt and marked it with a red sharpie. I quickly dropped the bolt in its hole and pushed so red sharpie ink would come in contact with the bracket marking the drill spot. After drilling that hole and cleaning the edges I returned the bracket to the cube. I reattached the hoses and bolted the bracket to the sump. Looks great and is very secure, it will look even better with the correct length bolts.
So now I will just need to run the wires and connect them to my Dynon EMS to show my fuel flow when the engine is running.
