Archive for July, 2011

Airwolf Adapter & New Oil Cooler

I put the porcupine fins on the oil filter and started building brackets for the remote filter installation. It’s surprising how much time it takes to fabricate brackets. If you look closely in the picture, you’ll notice that I used waxed lacing to hold the Adel clamps closed. The lace lays down fairly flat and allows me to get a nut and bolt started without too many cuss words. After the nut is started, I use a razor blade to cut and then remove the lacing.

The Airwolf oil filter adapter pickup is really a work of art. In my Continental O200 installation, I removed the original screen and replaced it with the Airwolf adapter. The fittings shown in this picture are just for test purposes. I’ll probably end up using 2-90 degree fittings.

Once I was satisfied with the fit of all my new brackets, I primed and painted everything white to match the engine mount. I’m pretty happy with how everything turned out. Note that I’ve removed the porcupine fins. I talked with a friend who tried them and said if they helped at all, it was VERY little. I’ll be sending mine back. For $100 they need to be more effective than the width of my temperature needle!

The pictorial manifestation of my oil cooler situation. I started with a used Stewart Warner cooler. I then switched to a used Positech cooler. I have now decided to go with a brand new Setrab cooler. It’s the one on the far right in this picture. It has about the same frontal area as the other two coolers, but only half the thickness. This is a 10 row cooler so I’m hoping it’s adequate for my O200. A friend is using a Setrab cooler in his Giles 200 with great results. The price was right at only $106–BRAND NEW!

Of course in true homebuilder spirit, I had to make a few modifications to my brand new cooler! I cut the mounting tabs off one side of the cooler to allow it to slip through a hole in my bottom engine cowl.

This was the painful part. I marked the outline of the material to be removed (yes, cut out) from my lower cowling. The idea is that I’ll slip the cooler down into a new air duct fabricated to provide a direct stream of fresh air to the cooler. So much for my shiny checkerboard cowling!

With the hole cut in the cowling, it was time to start fiberglassing in a few mounting pads to support the oil cooler. I used white duct tape to hold the cooler in place and then a couple of blocks of foam to help shape the mounting pads. This will be a multi-day, multi-step layup process so keep following along and the method to my madness will [hopefully] become apparent.

This is how I left the project when I left the airport at about noon today. With any luck, it’ll still look somewhat like this when I return to the airport tomorrow morning. It’s been getting into the 90’s each afternoon so I’m guessing the fiberglass will have cured by tomorrow morning!

We had a very special visitor at the airport today. Dick Vangrunsven of Van’s Aircraft stopped through on his way to Oshkosh. A few of us went out for BBQ this evening and had a great time listening to Mr. Vangrunsven. He’s a very smart and interesting person to talk to and I’m honored to have met him. When all the dust settles 50 years from now, I believe Mr. Vangrunsven will be seen as one of the top 5 most influential people in general aviation in recorded history. On top of that, he’s a really nice guy.

Still more cooling…

These are my upper and lower inner cylinder baffles. They rest on the top side and bottom side of the cylinders and are intended to force the air through the cylinder fins rather than allow it to flow through a big, gaping hole. I’ve been using nothing but safety wire to hold these in place, but have decided that a spring would be nice and would allow for easier removal and installation.

Here’s a birds-eye view of my engine installation with the inner cylinder baffles in place. Keep reading to see where I ended up modifying this setup to open up the top side of the cylinders a little more.

An overhead view of the engine with the newly redesigned plenum. Unfortunately, as near as I can tell, the new plenum design did absolutely nothing for me! Bigtime bummer.

Believe it or not, this little mod was good for 10 to 15 degrees in oil temperature! I bent a 3/4″ x 6″ piece of aluminum to a 45 degree angle and taped it to the aft lip of my cowling. The idea is that this lip causes a low pressure area in the exit airflow and helps to suck the hot air out of the engine compartment. Pretty snazzy.

It’s annual time so I started an oil change. This is the first oil change with a spin-on filter so I cut the filter apart to look for any signs of engine wear–like big pieces of metal stuck in the filter. I’m happy to report that none were found.

Since I’m now filtering my oil with a real live filter, the oil screen is no longer necessary. I used a torch like you’d use for sweating copper pipe to de-solder the screen from the big oil screen nut. This way, I can just change the filter and not worry about pulling the screen off for future oil changes.

While I had everything apart and just to make sure I wasn’t chasing a ghost, I decided to re-check the accuracy of my oil temperature sensor. I heated some water and stuck a cooking thermometer in the water alongside the oil temperature probe. I then compared the reading of the thermometer with what I was seeing on my oil temp gauge in the cockpit. I’m happy (I guess) to report that the two read within 2-3 degrees. (The width of the needle.)

I decided to open up the top side of my cylinders even more. I used a bent piece of wire about the gauge of a coat hangar to slide around the cylinders to provide a mounting point for my inner cylinder baffles. I took the fiberglass baffles that were on top of the cylinders and moved them to the bottom of the cylinders. You might also notice that I trimmed down the cylinder baffles a bit where the intake air first hits the cylinders.
I had a little issue a week ago or so where I had no oil pressure on startup after leaving the plane sit for about 2 hours. After a bunch of troubleshooting, I came to the conclusion that my oil filter and cooler system was plugged up. You’ll remember that I used a port off the left side of the engine to connect oil lines that would feed my spin on filter and oil cooler in series.
What I failed to account for in the original installation was that if either the cooler or the filter became plugged for any reason, the engine would be starved for oil. There were no bypass valves. Duh. Luckily, I discovered this problem on the ground and not in the air or we could have had serious problems.

After realizing the error of my ways, I decided to purchase an Air Wolf spin on oil filter adapter kit. When I called Air Wolf to talk to them, they said they’ve got a new filter fin kit that supposedly reduces oil temps by 20 degrees. What the heck, I thought, and I bought it. This thing really looks like a porcupine. It’s going to be a bit of a challenge to find a place to mount this bad boy.

Here’s another view of the filter fins. You can see that they cover about 300 degrees worth of the cooler. I’ll duct some cooling air to the filter to maximize the effectiveness of these fins.

Just in case the fins aren’t enough, I bought this spin on oil cooler port adapter from Steve’s Aircraft up in Oregon. This little baby spins on between the Air Wolf remote mount pad and the filter. It provides a pressure bypass valve and an in and out port for an oil cooler installation. After talking with the folks at Air Wolf, I discovered that the Air Wolf system doesn’t have a bypass valve per se… They, instead, count on the bypass capabilities of a CH43108 aircraft filter. That’s why it’s important to have a bypass valve for the cooler installation.
With all this stuff going on and a bunch of other things going on in my world, I’ll be lucky to have my plane flying again before the end of July. Bummer, really, because I was hoping to make it to a fly-in at Alamosa, Colorado on July 16th. I don’t think that’s going to happen. Oh well, there’s always next year!