Archive for April, 2011

Plenum, Oil Cooler Duct & Upholstery

My poor plenum tops have taken a beating with my oil cooler installation and then relocation. It was a shame to screw up my checkerboard paint, but it’s all in the name of progress, right? After grinding out all the previous ducting I had to re-glass the holes near the inlets. I used clay as a backing and then glassed the holes shut.

The lower half of the new duct to the oil cooler is attached to the cylinder baffles. As you can see, the cylinder baffles are held on with safety wire. I put a couple of nutplates in the lower duct that the top duct will attach to. The gap will eventually be filled with a neoprene ring. I needed a little space because there will likely be movement between the engine and the oil cooler (because the cooler is mounted to the engine mount).

The plenum is in place and completes the new duct to the oil cooler. With all the screws in place, it’s really a solid setup.

Here’s a birds-eye view of the engine compartment as it currently stands. You can see the patches towards the inlets where I removed the previous ducting. I used duct tape to seal the gap in the new plenum for now. Once I know the system is going to work, I’ll fabricate a neoprene sleeve for the gap.
I went up on Wednesday of this last week to test the new installation. I ran the plane wide open for 30 minutes to see how high I could get the temps In the old days, I could easily flog it into going to 225 degrees. I’m happy to say that the best I could do running around at 3000+ rpm for a full 30 minutes was 210 degrees. I have no intention of running around at 3000 rpm in normal operations so I’m calling this a success.
I de-cowled the airplane after the flight and found 2 small oil leaks. The first was an easy one… in fact it was one of those “duh” moments… The hose on the breather port was night tightened down. Woops.
The second leak came from my modified reducer fitting on the right side (looking at it) of my oil filter adapter. I remember being excited to see if the modified adapter was going to solve my clearance issue so I put the fitting on without using the Permatex teflon sealer. It leaked. Woops again. I stopped by the hangar last night at about 9pm on my way home from work and fixed both these issues in hopes of flying to breakfast this morning.

The other thing I did yesterday was that I picked up my new seat cushions with the new upholstery. A guy over in Brighton, CO built the seat cushions and did all the sewing, too. I could have picked from any material in the world for my upholstery, but ended up picking sheepskin. I purchased 2 pelts from Colorado Sheepskin Factory in Denver.
I was originally planning to go with a dark grey color, but nothing I found really blended well with all the other colors in the interior. I ended up going with black because black seems to go with everything. Now that it’s installed, I’m very happy with the look.
I went out to the airport today (Friday) with hopes of flying over to Greeley (KGXY) for breakfast. Unfortunately, by the time I arrived at the airport at about 7:30 this morning, the wind was already blowing in a direct crosswind at 16 knots. It would have been do-able, but I figured I’d get my fanny kicked all the way to and from Greeley so I decided to stay on the ground and work on the next project.
What’s the next project? Stay tuned for pictures and a narrative in the next entry.

Oil Filter & Cooler Hoses & Fittings

I made a simple bracket to hold my oil thermostat. I’ll attach the bracket and thermostat to the engine mount using the 2 Adel clamps you see in the picture. I was shocked to see how much the AN fittings added in terms of overall size to the thermostat. Luckily, space isn’t much of an issue under my cowling.

Here’s an overview shot of the entire installation. The oil line comes out of the engine to the filter then from the filter to the thermostat. From there, it goes in and then back out of the cooler and then from the thermostat back to the engine. Lots and lots of hoses so I’m hoping this pays big dividends in terms of oil temp reduction.

Here’s a close-up of the installation of my hose fitting. I learned from a friend to put some tape on the hose before you start screwing the fitting together to make sure the hose isn’t pushed out of the fitting as the parts are joined. I’m using Aeroquip Lite hose. It’s about $8/foot, but it’s approved by all the different car race associations as fireproof. It’s also rated for 500psi so that should pretty much handle my 90psi (max) O-200!

A close-up shot of where the oil lines come in and out of my case. This is the same location Continental uses for the installation of an oil cooler, but it’s a custom fitting. The O-200’s rarely had an oil cooler installed in a Certified installation. They put oil coolers on Cessna 140 planes, but only in the seaplane configuration… Fairly rare. Cessna wants many hundreds of dollars for their official fitting so I was happy that the prior owner of my plane had this fitting custom built for this engine. You’ll remember that I tried the F&M or F&S or whatever brand oil filter adapter and oil cooler spin on adapter, but my engine mount interfered.

A close-up shot of the fittings and hoses coming and going from the thermostat and the spin-on oil filter adapter. If you look closely you’ll notice that the blue anodizing has been removed from the fitting on the right side of the oil filter adapter. I had a clearance issue so a friend cut the threads down by about a 1/4″ and then re-threaded the fitting. Worked perfectly.

A close-up shot of the fittings on the oil filter adapter. You can see where the modification to the right fitting gave me just enough clearance to account for the curvature of the firewall flange.
I don’t have a picture, but a friend came over to observe an engine run to check for leaks. Good news! No leaks. With 6 hoses and 12 fittings, I’d never want to just assume I did everything right. It’s very satisfying to have a dry installation.
The fiberglass work on the plenum is coming along nicely. I’m pretty much to the point of using tape to cover a few holes and testing the system. If the weather is good, I’ll tape up the holes and go flying. If the weather isn’t flyable, I’ll spend the day doing more fiberglass work, instead. I’ve got Monday, Thursday and maybe part of the day Wednesday of next week to work on the plane. I’m planning to head down to Abilene, TX on Friday for an air race on Saturday. I think the only thing that’ll stop me this time is weather.

Plenum, fittings, thermostat and cheeseburgers

This is a top-down view of the new oil cooler ducting with the fiberglass cloth in place. It’s not perfectly straight airflow, but it’s much better than the previous installation.

This is the oil cooler exit air plenum wearing a few layers of fiberglass cloth.

This is a sampling of the fittings I ordered for the oil cooler installation. The silver piece with 4 ports is my new oil thermostat. The brass right angle fitting is a new breather port fitting. I’m going to solder in a piece of copper pipe to reduce the amount of oil that finds its way to the belly of my airplane via the breather tube. More pictures of this mod later.

Some folks were asking about the weight of my new oil temperature thermostat so I took a picture of it laying on a postage scale. The weight of the piece isn’t significant, but when you consider all the related fittings and hoses, I’m sure I’ve gained a few pounds. Gotta be done!

Sometimes it’s hard for people to visualize just how the fiberglass process plays out so I included this picture. Since I used a combination of foam and clay for my mold (plug), once the epoxy resin cures, I have to dig the foam and clay out from the inside. It takes a bit of time and patience, but it’s kinda cool to see the part take shape.

Here’s the new exit air plenum box after a bit of trimming with the Dremel tool and some light sanding. I always end up leaving a few “pokeys” (extremely sharp shards of resin-impregnated fiberglass) on my layups so I do a little light sanding to minimize my blood loss when fitting the new part.

This is the bottom piece of the new oil cooler ducting prior to much trimming or sanding.

Here is the top half of the plenum with the new oil cooler ducting grafted into place. I’ll test-fly the new installation before I spend a bunch of time sanding, filling and painting. No sense in spending a bunch of time on cosmetics until I know the installation will work.

I submit this picture as evidence of my progress towards full-fledged adulthood. My new year’s resolution was to start acting more like an adult and less like a college kid. Part of my plan is to start incorporating furniture and vegetables into my day to day existence. I still don’t have any furniture in my house, but I have started putting vegetables on my cheeseburgers when I barbecue! Those are some darned-fine looking cheeseburgers if I do say so myself.

Upper plenum and exit air diffuser box

I spent a little time out at the hangar today and continued my work on the ducting for my relocated oil cooler. I’m making the new duct as a 2-piece part. The lower half will be attached to the cylinder baffles and the upper half will be a part of my fiberglass plenum. There was a pretty large volume of space to fill so rather than use 20 pounds of clay, I first filled the void with shop rags and then put duct tape over the rags so the clay wouldn’t stick to the rags.

With the rags and the duct tape in place, I started adding clay. It took me about 40 minutes to achieve this shape. As a little tip, it is tremendously easier to work with this clay if you first heat it thoroughly. I’ve got a microwave I use to heat my lunch in every so often. Turns out it heats the clay up fine, too!

Once I was happy with the overall shape of the clay, I painted it with 2 coats of PVA mold release. Again, it pooled in the low spot, but these dimensions aren’t critical to the thousandth of an inch so I’m not too concerned. It’ll just take a while to dry.

This is the plug for my oil cooler exit air diffuser box. Again, to avoid having to work with a 20 pound glob of clay, I started with a foam core. To help stiffen the foam up, you’ll remember that in a prior work session I coated the foam with a mixture of micro balloons and epoxy. This method seemed to work pretty well.

In the process of poking around the engine compartment looking for air leaks in my cooling system, I think I may have discovered the cause of my erratic CHT readings on my #2 cylinder! I’m not sure if this worked its way to being loose or if I somehow failed to torque it down, but this is how I found my #2 cylinder temperature probe when I de-cowled the engine. I love it when a solution is simple and obvious!

Oil cooler ducting

I spent about 1-1/2 hours out at the hangar this evening after I finished my 4-day trip. This is my new piece after I’ve pulled it out of the clay mold and scraped the clay off. Of course I’ll need to trim it and do a bunch of sanding and filling before it’s anywhere near finished.

Since I’m abandoning my “Y-duct” near the front of my plenum, it was time to hack off my handiwork. Obviously the entire plenum will need to be refinished once I’m finished with the new oil cooler installation.

In this picture I’ve trimmed the new piece and have cut back the original plenum. I’ve also sanded a strip of the plenum all the way down to the original fiberglass. This will give me a nice surface to splice into the old plenum to continue the chamber back to the oil cooler. The plan is to have the bottom piece of the chamber attached to the cylinder baffles and the top top piece will be an integral part of the plenum. I’ll probably end up creating a gap between the cylinders and the oil cooler and bridging the gap with neoprene. I’m afraid the part would crack due to the shaking/twisting of the engine relative to the engine mount. Since the oil cooler is hard-mounted to the engine mount and the cylinders are attached to the engine which is attached to the mount via rubber mounts, I’m guessing I’ll need to make allowance for the movement. I’ll take a picture and point it out when I get to that point. I’m having a tough time describing it.

Fiberglass ducting for oil cooler

I started the process of fabricating a duct to provide high pressure air to my oil cooler. I used a bunch of vinyl tape to protect different surfaces from resin. The resin releases easily from this vinyl tape. I used a few pounds of clay to form a reasonably smooth duct from my existing rear cylinder baffle to the oil cooler.

I painted PVA mold release on the clay. You can see where the mold release pooled near the oil cooler. If my dimensions were absolutely critical, I would have had to do something about the pooling, but since it doesn’t really matter, I’ll just accept the longer dry time and move on.

Here I’ve laid down somewhere between 3 and 4 layers of 6 oz. fiberglass cloth over the clay and PVA mold release. You can see where the green from the pooled mold release shows through the wet fiberglass. As I mentioned before, I wasn’t concerned about the pooling, but it *is* important that the PVA is dry before you start laying the fiberglass cloth over it. I let the mold release dry a full 24 hours before I did the layup.

I try to have multiple projects going on simultaneously while I’m doing fiberglass work. If you don’t do this, you end up wasting a bunch of time because you have to wait for each layup to cure before making any additional progress. This is the start of a mold for the oil cooler exit air diffuser box.

This is all I’m going to do in foam for the exit air diffuser. The rest of the shaping will be done in clay. This would be a huge chunk of clay if I didn’t start out with some foam. I’ve painted the foam with a mixture of resin and micro balloons so that the clay will stick to the foam core more readily and my clay won’t be contaminated.

Oil Cooler Relocation & A Little Flying

Just for a little background, I didn’t originally install an oil cooler at all. I had some pretty high oil temps on my first 2 flights and decided I’d install a cooler. Because I hadn’t made any provision for a cooler in my original plans, I looked for the most convenient location. I installed the cooler on top of the engine and re-worked my plenum to provide for a small fiberglass tube to feed the cooler from each side of my forward intake. I never got around to making it look pretty because I was waiting to see if this was a viable solution.

The short story is that my first cooler installation worked, but just barely. I sometimes had to run at reduced power settings to avoid over-temping the oil. Not good. I’ve got a fairly high quality Stewart Warner oil cooler so it should be more than adequate if given an adequate supply of air through the fins. I’ve decided to re-locate the cooler to a more traditional installation behind the cylinders. I’ll redesign my plenum to feed air to the oil cooler.

In the picture, above, you can see 2 of brackets I fabricated to support the cooler. This picture shows the 3rd bracket. I used Adel clamps to attach the brackets to my engine mount. I realize the black silicone at the edges of the cooler is a little tacky. I’ll take care of that as I move forward with this new installation.

I’ll make something similar to this diffuser box for the backside of the cooler. What I’d like to do is make a very smooth bend to point the outgoing air towards where the opening is at the aft edge of the lower cowl. I fabricated this diffuser box many months ago, but it ended up not working out. I just held it in this picture as a general idea of what I’ll be shooting for.

I snapped this picture because it shows the brand and part number of the spin on oil filter adapter I recently installed.
I’ve finally been doing a little flying lately. I had planned to go visit my older brother last Thursday and then head down to Taylor, Texas on Friday for a Sport Air Racing League race on Saturday. Well, the weather didn’t really cooperate. You’ll recall that Thursday was the day the big storms hit Sun ‘n Fun in Florida. There was a stream of fronts moving through the country on Thursday and they seemed to start about halfway between Loveland and my brother’s house in eastern Kansas.
I could have fought my way down to Taylor on Friday, but I’m afraid it would have been a fight. Wherever it wasn’t raining, the winds were blowing in excess of 25 knots. With that much wind and weather, it was going to be a stressful and bumpy trip. I just can’t get excited about doing a stressful and bumpy trip for fun, so I stayed home.
I ended up flying 4 out of 5 days in a row. A couple of the days were pretty windy and bumpy so I just made a beeline for the lunch destination and then headed straight home afterwards.
Tuesday was the longest of the lunch destinations. A friend is breaking in a new engine overhaul in his Sidewinder so we headed out to Sterling, Colorado for lunch. It’s about 93 miles each way. I’m always a little bummed that my friend is 25 mph faster than I am and seems to meet or beat my fuel economy, too. He’s got an MT electrically-adjustable prop with an O-320 engine running dual P-Mag electronic ignition systems.
Full tilt boogie, I’m still seeing about 175mph true airspeed. I don’t really mind running my engine at high RPM’s. Somehow it just seems to come alive at about 2900 rpm. My Catto prop is redlined at 3200 rpm. I’m thinking that when I finish my wheelpant installation, I’m going to get with Craig to have him put a little more bite in my prop.
I did 4 laps in the pattern yesterday before officially declaring the plane out of service for oil system maintenance. The oil temp reached about 205 degrees F while doing touch and go’s so there’s definitely a need to address my cooling situation. The OAT yesterday when I was doing touch and go’s was about 75 degrees F… so really fairly mild when you consider I’d like to run an air race or two in Texas this summer!
I’ll do my best to keep everyone posted on my progress via this website. I’m going to do my best to have the oil cooler installation finished by the end of next week because I’d like to run in an air race down in Texas on April 16th.