Rod's Midget Mustang Project

This is a test to see if the text will wrap to the right of the photo like all my other posts. I’ve been having a difficult time with my new software.

OK. It looks like it’s working so I can start updating the blog again. Sorry for the lack of updates.

This photo was taken by a GoPro Hero2 camera mounted to the underside of my wing. It doesn’t have a remote shutter release button so I set it up to take a picture every 1/2 second. I would up with over a thousand pictures. I’m going to work on a more solid mount that I hope will help to eliminate some of the waviness you see in this photo.

While I was in the process of replacing my accessory case, I decided to modify the inside of my plenum to even out my CHT’s. I added a small ramp about halfway between the 2 cylinders on the left side of the engine. Before the mod, the back cylinder was cold so the theory is that the ramp will deflect more air towards and through the aft cylinder instead of letting it pass to the back of the plenum. It worked pretty well, actually.

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I guess I didn’t take any pictures as I was building these new hoses. I was so disgusted at having to re-do all of them that I just wanted to get it done and not stop for photos.

I ordered brand new Aeroquip AQP fittings and brand new Aeroquip stainless hose. I know you don’t have to use fire shield on stainless lines when used for oil, but stainless really scares me in terms of chafing potential so I went with the fire sleeve. Making hoses out of high quality stuff is REALLY expensive. I hope when I decide to sell my plane the buyer appreciates the difference!

I also pressure-tested 2 out of four of these hoses to 600psi. They really shouldn’t leak or fail again! Two dead stick landings are plenty for me for about the next decade or so!

This is the accessory case after the paint dried and before I removed the masking tape. I’m pretty happy with how well the red rattle can engine paint matched my original red powder coating. The generator cover laying on top of the case is an example of the original powder coating.

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Unfortunately, after all the hassle of replacing the oil pump and accessory housing, I had problems again with my oil lines. Even after replacing this hose and leaving a little more wiggle room to allow for more wiggle room between the oil filter and the engine, the line still broke–again.

The short story is that I was close enough to the airport to shut the engine down and glide to the runway. Even made the reverse high speed turnoff. Dripped oil all over everywhere. A real mess… and it got my heart rate up pretty well, too.

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If you look down towards the bottom of the battery you can see where the hose failed. After significant discussion with a bunch of different people, it was determined that I made a significant mistake in mixing one brand of hose (Aeroquip) with another brand of fitting (Earl’s). More than the brand name, I think it was an incompatible type of hose. Keep reading for future posts showing how I fixed this oil line problem once and for all.

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A friend of mine has an engine vibration measurement machine. For a small fee he helps all kinds of folks with Experimental aircraft balance their props. This particular plane is a Giles 200 based in Longmont, Colorado. If anyone in the area needs a prop balanced, shoot me an email and I’ll put you in touch with Dave.

Things haven’t been going so well for my little airplane these days. I keep getting stranded away from home because my oil pump won’t seem to stay primed. When I start the engine, it fails to make oil pressure. There are all kinds of hocus pocus tricks you can try to get the pump primed again and I’ve tried them all. TWICE!! I finally reinstalled my custom made fitting on the left side of my engine case and used a T-fitting to add a primer line (the orange line in this picture). It worked, but not for long…

The long and the short of the situation is that my oil pump gears and/or the oil pump housing had worn beyond tolerances and could no longer make pressure. This is my accessory housing after I removed it from my engine. The plate in the middle covers the oil pump itself, which consists of 2 hardened steel gears.

Now: I’m no engineer, but even I can see where putting 2 hardened steel gears inside an aluminum housing might lead to some wear issues.

This is the aluminum plate that covers the oil pump and holds the gears in place. You can see where the gears have caused some wear marks on the plate. A lot of people are successful in restoring oil pressure by lapping this plate and reinstalling it. By the time I had gone to the trouble of removing my accessory case, I was going for the sure thing… not a maybe.

Here are the gears in the housing. The square drive on the lower gear engages on either the crank or the cam (can’t remember now) which then spins the gears. The backside of the top gear (not shown) has the square drive output for the tachometer.

You can see the wear on the housing from where the hardened steel gear has rubbed. There was a similar wear pattern on the other side of the housing, too.

I could have the old housing remanufactured for $850 or purchase a new housing for $905. The new housing is on the right. Ouch.

The new accessory housing from the backside. Sure is pretty with that gold finish…

I’ve never actually painted a chess set, but I imagine it to be very similar to taping off and painting this accessory housing.

I reinstalled the accessory housing. Sounds simple enough, right? Wrong. I needed all new gaskets for everything attached to the accessory housing including: Both magnetos, the starter, the generator (capped), the tach drive housing and, yes, even the oil sump. By the time I purchased the accessory housing, a new oil pump kit (gears and the aluminum door) and all the gaskets, I had spent the better part of $1500. All I can say is that I’m glad I could do the work on my own because I’m sure it would have been another $1000 in labor if I was paying somebody else to do it!

Once I decided to put my oil cooler at the bottom of the cowling, I needed to re-work the aft portion of the left side of my plenum to remove the air outlet for the oil cooler. My poor plenum has been hacked up and re-worked beyond recognition. I used clay to re-shape the aft portion of the plenum.

I used PVA mold release to keep the glass from sticking to the clay and then laid up about 4 layers of 6 ounce cloth. Complex shapes are pretty easy with clay and fiberglass.

Once the resin cured for the top half of the plenum, I trimmed it to fit and then covered it with duct tape in preparation for the next fiberglass workday.

Once again, I used PVA mold release on everything I didn’t want the resin to stick to. I made a lip for the top of the plenum to nest inside when the plenum is installed. Worked out pretty slick.

I finally got around to installing my tailwheel attach point fairing… sorta. I used duct tape for now because I wanted to make sure it didn’t cause any problems. It fits nice and cleans up the look a bit so I’ll probably have it painted when I install my wheelpants this winter.

Here’s a profile shot of my new oil cooler inlet. I think it looks butt-ugly so I’m not sure it’s going to last long. We’ll see how effective it is…

Being the absolute gadget freak that I am, I bought a new toy. You can never have too many GPS’s, can you? The new, big, GPS is an iFly700 from Adventure Pilot. I think it’s a great value at a little less than $600 for the unit itself and a year’s worth of sectional charts and airport facility directory. I hard wired it to the master switch and installed an external GPS antenna under the cowling.

With the fiberglass work mostly finished for the new oil cooler installation, it was time to finish the installation of the Airwolf remote oil filter installation. The gold piece to the left on this picture is the oil pickup adapter from Airwolf. It replaces the original oil screen. You’ll notice that I’ve installed a nifty AN fitting with a 1/4″ port for an oil pressure transducer. Summit racing sells these fittings as test fittings, but they work well to provide an additional oil pressure pickup port. I now have 2 independent sources of oil pressure indications. The primary source is a line coming off the left rear side of the engine case. That line goes to a transducer that drives the oil pressure gauge. The pressure switch shown in this picture turns on a low pressure light when there is less than 5psi and activates my Hobbs meter when there is more than 5psi.

This is a birds-eye view of the remote oil filter installation with all the hoses attached. If everything goes well, I can accomplish an oil and filter change without removing the lower cowling. The silver piece below the gold piece is made by Steve’s Aircraft. It spins on the oil filter adapter to provide ports for oil cooler lines.

I ran into a little problem when I ran the engine for a leak check after installing the spin-on oil filter adapter and the Steve’s Aircraft oil cooler. This stud that comes out of the Air Wolf adapter is slightly too long to allow the Steve’s Aircraft adapter to set properly against its rubber o-ring seal. The 1/32″ gap allowed oil to spray out between the parts.

Looking back on this picture taken before the leak check, you can see a little daylight between the silver part and the gold part. I incorrectly assumed that when the silver piece bottomed out it was bottoming out against the o-ring seal when it was actually bottoming out on the treaded stud protruding from the gold part. Luckily, I’ve got a good friend who’s a retired machinist who’s got a lathe in his garage. He took off about 1/4″ from the stud and all is now right with the world.

I cut a hole in the bottom of my cowling and poked the oil cooler through. I used clay to help define the mounting points for the cooler. The phenolic blocks sitting on top of the cooler will be encapsulated in fiberglass to provide for a mounting surface that can be tapped to accept a #8 screw to hold the cooler in place.

You can see the phenolic block now encapsulated in fiberglass cloth and a resin/flox mixture. The clay visible in the previous picture is still in place so that when the whole mess cures I can remove the clay and have nice clearance for the flanges on the oil cooler.

With the cooler mounting points firmly established, the next step was to fabricate a nice inlet for the cooling air. I used clay to form a smooth transition.

The intake scoop is now pretty well finished and ready to be bonded to the lower cowling. I’ll need to finish some of the transitions once it’s bonded in place, but it’s ready to go for a test flight.

This is how the mounting pads turned out. You’ll notice I’ve got the black square from my original cowling checkerboard paint scheme taped off. I painted all my new fiberglass work white before I bonded the scoop in place. I don’t like to leave any fiberglass unfinished because it has a tendency to soak up dirt and grease/oil.

A rare treat! My brother’s girls stopped by the hangar for a quick visit. As you can see, my brother’s 5′3″ 100 pound 12-year-old fits nicely in a Midget Mustang cockpit… much better than her Uncle Rod!

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.

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.
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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.
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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.
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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!

Here’s a bird’s-eye view of the new plenum pieces painted and installed. I’m very happy with how they turned out. Now it’s just a matter of connecting the dots–joining the original plenum with the new pieces by fabricating a fiberglass lid.

Once again my good friend Phil came to my aid with my fiberglass work. He’s got more fiberglass experience and tools than any sane person ought to have. Using Phil’s equipment and expertise, we made a vacuum-bagged layup consisting of 2 layers of cloth, a 1/8″ layer of foam and another 2 layers of cloth. To complete the vacuum bagging package, we laid on a layer of peel ply and then a layer of breather cloth. The whole mess then goes into an airtight bag and a vacuum is drawn.

This little pump supplied the vacuum. We placed the whole package on the top of my engine with bags of lead shot to hold everything down nice and tight against the existing plenum and my new metal pieces. It took about 6 hours to cure to the point where I could remove the vacuum. I left the weights and everything else in place until the next morning.

I was back at it again first thing Saturday morning. This is what it looked like as I started pulling the peel ply and breather cloth off the cured part. The gold color is the foam core as the 2 layers of fiberglass are pretty much transparent once all the excess resin is sucked out. The piece is surprisingly light.

I laid the piece back on the engine to get a feel for just how much I’d have to trim. It fit surprisingly well, but will obviously need to be trimmed.

With the front-to-back trimming complete, I next marked strips along each side. I’ll use a Dremel tool with a small cut-off wheel to carefully remove the first two layers of fiberglass from the strips along the edge. This will allow the fiberglass, without the foam core, to rest on my new metal flanges.

Once the first two layers of fiberglass were removed, I just had to scrape the foam core out to leave the remaining 2 layers of glass exposed. This wasn’t a difficult process.

To finish the flange, I used a Dremel tool with a cone-shaped grinding tool to grind a 45 degree bevel in at the edge of the remaining foam core along the length of the flange. Even using the vacuum process, it’s easier to get fiberglass cloth to lay down over something less than a sharp 90 degree angle. After the bevel was cut, I applied another 2 layers of cloth tape along the flange so that the finished flange is 4 layers thick. 4 layers of cloth wouldn’t be enough for the entire plenum (without the foam core), but it’ll work well for the flange.

I drilled and clecoed the new fiberglass piece in place. I laid the blue tape on a flat surface and made my marks for the holes so they’d be equally spaced. It’s tough to determine the spacing on a curved surface so the tape works well. I drilled through the new plenum and into the flanges of my new baffle pieces. I also drilled and clecoed a few holes through the new plenum into my old plenum pieces.

I took the entire plenum off as a single piece. My plan is to remove 2 layers of cloth and the foam core where the new piece will mesh with the old plenum halves. This should make it easier to graft the new piece to the old pieces and create an invisible transition so that the entire plenum will be a single piece. Obviously there are some openings in the corners that I’ll have to address with additional wet layups.