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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.
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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.
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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.
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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.
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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.
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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.
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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!
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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.


Maintenance Day

I was off work this week from Thursday through Monday. I had a few things to do Thursday, so I didn’t fly until Friday morning. I went over to Greeley for breakfast. It’s always nice to run into a few old friends and chat over breakfast. I topped off the fuel tank at $4.21 per gallon (which is about 50 cents per gallon cheaper than KFNL) and headed home. I removed the upper and lower cowling and stated draining the oil for an oil change. I finally made it back out to the hangar on Sunday to finish the oil change. I’m hoping to have all the parts and pieces gathered up by the time my next oil change is due so that I can install a spin-on oil filter at that time. Wonder how long it’ll take me to rack up another 25 hours?

Since I have a wooden/composite prop, I need to check the torque on the prop bolts on a regular basis. I’ve decided to make it my policy that I will check them whenever I change the oil. Since I had the spinner off anyway, I decided to install nutplates on my spinner backplate. I’m doing this in anticipation of doing a dynamic balance on my prop. Normally, during a dynamic balance session, the machine tells you where to place weight on your spinner to balance the engine and prop installation. Without the nutplates, adding weight would require removing the spinner to drill a hole in the backplate to install a nut and a few washers as weight. I decided it would be simpler to just have nutplates positioned every 30 degrees so that installing or removing weights would be quick and painless… and I wouldn’t have to beat up my spinner taking it on and off multiple times as we dial in the balance. I used AN470 rivets (the round headed ones) rather than the flush rivets that are normally used for nutplates because I didn’t want to machine countersink the backplate–removing more material– and making it just a little weaker. The heads of the 470 rivets shouldn’t be a problem in this application.

Next up on the days’ activities was checking and adjusting my landing gear alignment. A friend suggested I should be using greased plates under each main tire to allow the gear to reach its natural point with weight on the wheels. I stumbled across these plastic cutting boards at Wal-Mart the other day in the aviation aisle. They’re really slippery and much lighter and less messy to work with than greased steel plates. Total cost for 4 of these cutting boards was about $16. And hey… If I ever host a wine and cheese tasting party at my hangar, I’m all set for the serving trays…

I added another (my last) 1/2 degree shim to help correct a left-turning tendency. It was also time to replace my first set of tires. I only got 40 hours out of the first set, but that amounted to 122 [really bad] landings. I was using the 11×4.00-5 tires made by Cheng-Shin. They’re cheap at about $35 each, but they aren’t known for being durable or very high quality. I had a set of McCreary Airhawk 5.00×5 tires and tubes laying around so I installed those this time out of curiosity. It’ll be interesting to see how the bigger tires change the handling and landing characteristics. This is the standard size tire for Midget Mustangs and the RV-series of aircraft. Now that I’ve had the little 11.00×4’s installed, these things look like tundra tires to me!
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The McCreary tires are fairly cheap as far as tires go at about $52 each. Now that my alignment issues are pretty well fixed and my landing technique has improved, I think I’ll get closer to 100 hours of use out of a set of tires. I like the idea of the smaller tires because I think they look more in proportion to the size of the aircraft and they weight a little less and create a little less drag. This being said, however, if the larger 5.00×5 tires improve the handling dramatically, I’ll switch in a heartbeat!


Spin-on Filter, Forest Fire

I decided I’d really like to have a spin-in oil filter on my O-200 so I purchased this F&M brand adapter from Steve’s Aircraft in Oregon. Steve’s also makes and sells a spin on adapter that gives you ports to install an oil cooler. I ordered the whole shebang because it’s a really elegant solution. Unfortunately, as you can see in this picture, the engine mount interferes with the F&M adapter. Bummer. I ended up sending everything back to them yesterday. These guys were fantastic to work with, by the way. They’re very active with the Cessna 140 community and seem to run a nice business with some innovative solutions to common issues. Highly recommended.

When the F&M adapter didn’t work out, I reinstalled my custom-machined in/out fitting where I had hoped the F&M adapter was going to go. This bracket was custom fabricated by a local machinist. I run lines to and from here to and from the oil cooler.

Since I’m back to using the custom fitting, I’m thinking about using this automotive remote oil filter bracket. It’s about $100 from Summit Racing. I’m thinking I’ll come out of the case, go to the filter and then to the cooler and then from the cooler back to the engine. I don’t see why this wouldn’t work. It’s kind of like the Airwolf setup, actually… only about $400 less money!

Depending on where you are in the country, you may have heard about the recent forest fire just west of Loveland, Colorado. My family has owned mountain land west of town for more than 40 years. We’re down to 80 acres at this time and it was, unfortunately, part of the recent fires. I went up earlier this week to take a few pictures. The TFR was still in place up to 9500′ MSL so these were taken from approximately 2500′ AGL. It’s kinda cool to see the orange line of fire retardant. Less cool to see how much of our property was burned. I’d have to say that the Midget Mustang isn’t necessarily a good photo ship!


Battery Charger

Today I installed this Hella receptacle for my battery charger. I’m not sure exactly what the real name for this style of receptacle is, but everyone refers to them as “Hella.” BMW motorcycles use them as power ports for accessories and heated clothing.

I liked the plug because it’s got a spring-loaded cap and it’s rated for up to 15 amps DC. It’s sort of like an undersized cigarette lighter plug, but it kind of snaps into place in the last 1/4″ of insertion, too, so it stays put–unlike cigarette lighter plugs that always seem to back out.

This is my whiz-bang Odyssey battery charger/conditioner/maintainer. I figured that since I had an Odyssey battery, the Odyssey folks probably know how to make an appropriate battery charger. The nice thing about this one is that it’s got a quick charge capability, but it’s also “smart” in that it reduces the charge as necessary to a variable maintenance level to prevent over charging if you leave it plugged in forever. The downside to this is it’s pretty big and it’s got a fan that runs constantly whenever it’s plugged in. I’ll probably invest in a different, smaller charger for traveling.

Storm clouds near the airport this evening. It was a funky weather day around KFNL today. For a few minutes this evening I thought we might be watching for funnel clouds.

I laid-up this oil cooler diffuser box for a friend today. He’s got a Sidewinder and has been very helpful to me in my Midget Mustang project. It was the least I could do for him. The more I think about it, I think I’ll probably re-do the diffuser box for my oil cooler. The tubing size is just a little too big for my tastes.


Oil Cooler and More Photos

I test-flew the oil cooler installation on 07-16-10 to get an idea of how well this setup was going to work. It lowered my oil temps by a solid 25-30 degrees! Success, as far as I’m concerned. I still needed to plug the gap between my diffuser box and the oil cooler fins. I applied vinyl tape and some Part-All mold release to my diffuser box.

I then attached the diffuser box to the oil cooler and applied some black RTV to fill the voids.

The next morning, before flying the plane again, I took it all apart and removed the tape. What was left was sort of a crude-looking custom gasket. I think I can make this look prettier, but that will have to wait until I do the finish work on the plenum itself. I’m having too much fun flying to make stuff like this look real purty.

After a fantastic 1.2 hour flight on 07-18-10, I decided it was time for a few photos. This is one of my favorite viewing angles for the Midget Mustang. I just love the shape from an overhead view. I’ll have to find a little better lighting the next time I do this.

I think this is the first time I’ve posted a picture of my panel with all the labels applied. Aerographics made the labels for me. I think they did a fantastic job. If you look on the GPS, you can see my track line for the first 5 flights. Lots of laps over the top of the airfield!

As I mentioned above, today’s flight lasted 1.2 hours on the Hobbs meter. The temps were under control and I finally felt confident enough to leave the pattern long enough for some steep turns and a few stalls. I’m very happy to say that it stalls clean, power off at 70 mph indicated. Each notch of flaps lowers the stall speed approximately 3-4 mph with the full-flaps stall occurring at 58 mph indicated. MUCH better now than before the rebuild.

The stalls also broke straight ahead with plenty of warning in the form of reduced control effectiveness and a gentle buffet. Recovery was immediate by reducing back pressure and applying power. I also did a few 90 degree banks and rolled rapidly from 90 degrees left to 90 degrees right. Wow! This thing is wicked quick in roll. I banged my head on the first one. I’ll have to work hard to learn to NOT introduce a pitch input when rolling left/right. The elevator is very sensitive.

I wanted to put in a plug for these nav lights. I’ll have to update this post to include detailed information about manufacturer, but I’ve been really happy with these little lights. They’re obviously LED and also have a strobe light. There’s a single power pack for the strobes which I have mounted under my baggage floor. The wingtip lights are VERY lightweight at something like 11 ounces. I modified the wingtips to include a mounting base for the lights.

I’ve probably already got a picture of this somewhere, but here’s a shot of my cockpit lighting installation. The row of blue lights on the canopy provides just the right glow to see the instruments at night. The good news is that there’s a lip of plexiglass from the canopy that shields the pilots eyes from the strip lights themselves. All you see from the pilot’s perspective is the glow from the lights, not the lights themselves.

I’m away from home at work this week from Monday through Wednesday. I’m hoping to fly again this Thursday and Friday. I’d like to do some touch and go’s to make sure I can land this thing in a reasonable distance. I made 4 landings this morning using an over-the-fence speed of about 90 mph. I think with a little more confidence, I’ll drop that to 80-85 mph. The plane was very controllable at that speed and still had plenty of energy for a flare and a little float. I did 2 wheel landings and 2 3-point landings. They were all very controlled and the plane showed no signs of darting in any particular direction.

If all goes well, I’m planning to fly up to Mitchell, SD this weekend to hang out with the Air Venture Cup racers. I’ll spend the night in Mitchell on Saturday, watch the race start on Sunday morning and then head home before noon on Sunday. I’ve got a little bit of vacation time at the end of this month that I had planned to use for an Oshkosh visit, but since that’s not going to happen, I’ll probably just get to work installing wheelpants and fabricating my aux. tank. I’d like to participate in a few of the SARL races this year.


Oil Cooler

Here is the assembly with the front half of the tubing bonded in place and sanded lightly. I’ll install it and test fly it before doing any finish work.

Here it is installed on the engine. I’ll need to plug some holes at the oil cooler with a little RTV, but other than that, it fits perfectly. I’d rather not have the air change directions so much and so abruptly, but everything’s a compromise so we’ll just see how this works.

You can see how the oil cooler ducting has a separate intake within the cowling intake. I haven’t measured it, but my highly-calibrated eyeball says it’s a little over 1 square inch of intake area.

I re-routed the 1/8″ copper line for my manifold pressure transducer to go under the oil cooler hoses rather than over the hoses. There was clearance before, but I was afraid the heavy hose might sag in time and put pressure on the copper tubing. Copper tubing has a tendency to crack anyway. No since in irritating it unnecessarily.

You know what they say about guys with big feet… They don’t fit too well in little, tiny airplanes. The sneaker on the left is my standard work at the shop shoe. I purchased the Simpson racing shoes on the right because they are far less cumbersome when flying my little plane. It’s amazing how much difference a quarter inch here and there can make when fumbling for the rudder pedals.


Oil Cooler & Aux Tank

With easy access to the inside of the oil cooler ducting, I used a little clay to radius the corners of the box. This is a pretty simple layout, but it still takes time because once you place the glass, you’ve got to wait a day or so for everything to cure.

Once I was pretty happy with how the diffuser box was going to mount to the oil cooler, it was time to bond the tubes to the cylinder intake plenum. I had originally considered making the tubes detachable from the plenum, but decided this wasn’t necessary.

Since the front half of the assembly hasn’t been bonded into place, I took advantage of the good access and applied a few layers of cloth to smooth the opening.

I decided to continue the tube to the front of the intake plenum to make sure the cooler received plenty of air. I used modeling clay to establish the shape.

It was a little difficult applying cloth and resin to the inside of the cavity, but you can see in this picture with the clay mold removed, it actually came out pretty good.

I made extensive use of my Dremel tool with the cone-shaped grinding stone attachment to smooth the rough edges of the fiberglass layup. With this portion completed, my next goal will be to join the front half of the intake to the rear half.

Keeping in mind that all of the stuff I’ve described above happened over the course of a few days, I’ve always found that it’s good to have something else to be working on while you’re waiting for resin to cure. I decided to start working on my auxiliary/ferry fuel tank. This is the big block of foam I started with.

I cut the big block of foam to the approximate size and shape and then added a few pieces along the edge to minimize the amount of filler I’d have to use to achieve the final desired shape. I glued the block of foam to the seatback so that I could test-fit the seatback to make sure everything fit.

Once the block of foam had been sanded to final size and shape, I applied Bondo to the foam. Bondo sands well and can be painted. My standard practice is to finish the Bondo as if it were going to be the finished piece. I sand and fill all the imperfections and then paint the Bondo so that (a) the fiberglass will release easier from the mold and (b) the finished surface of the fiberglass part will be very nice right out of the mold–minimal, if any, sanding.


Oil Cooler Intake

Through a strange twist of events at work today, I ended up with the evening off. I have to go back to work first thing in the morning, but I took a little field trip out to the hangar this evening before bed and removed all the masking paper from yesterday’s fiberglass session.

Here’s the assembly looking at it from back to front. I haven’t separated the new piece from the original cylinder plenum pieces, yet. I’m thinking I may use industrial strength velcro to attach the oil cooler tubes to the cylinder plenum pieces. It’d be secure, yet removable when necessary.

The new piece separated from the plenum. You can see the clay and the PVC pipe through the translucent fiberglass.

I trimmed a few of the sharp, pointy edges and then cut the part down the middle, lengthwise. I’ll dig out the clay and remove the pipe sections which should leave a fairly clean piece.

Here are the two halves laying on a work table. They’ll need a fair bit of clean-up and several more sessions of glass before I’m ready to join the two halves permanently. When I did the initial fiberglass layup, my intention was not to achieve final thickness or strength. My goal was to get enough glass on the mold so that it would hold a shape and allow me to put the finishing touches on from both the inside and the outside. It is turning out very well as far as I’m concerned.

I’m excited to move on to the next stage of layup on this piece, but I have to go to work tomorrow morning, early, until Thursday afternoon. I’m off from Friday through Sunday this week so I’ll try to make a bunch of progress at that time. Now that I’ve flown the airplane, I can’t stand the thought of NOT flying it again very soon!


Oil Cooler Intake Air

I removed the cylinder plenum covers along with the new oil cooler intake plumbing as a single piece. I used mold release between the new fiberglass and the cylinder plenum, but I did my best not to separate the parts in hopes of glassing the underside of the oil cooler intake today with the whole thing turned upside down on my workbench. It’s a whole lot easier to apply resin to fiberglass cloth when gravity isn’t working against you!

There were a few drips of resin on my clay mold leftover from yesterday’s layup. I picked them off with my fingernail and applied a little additional clay and a little additional mold release. I also noticed a few spots where I could have done a better job with my clay work so I futzed around with that a little, too.

Here’s the way I left the part when I was finished working today. I laid up 3-4 layers over everything. I did my best to smooth out the edges so there wouldn’t be any jaggies, but I’m sure it’ll take some sanding before it’s smooth. My plan is to split the intake in two pieces to break it free from the mold. I’ll then bond the pieces back together using a combination of resin, flox, and a few strips of glass cloth. I’m sure I’ll also be doing some finish work around the edges from the inside of the intake before I glue it back together. There is a bunch of work left to be done.

I’m headed to work tomorrow morning at Oh-dark-thirty. I really should be in bed asleep right now, but the noise from all the fireworks is keeping me up anyway so I figured I’d make this post. I live in a neighborhood full of 60+ year-old, wealthy retired folks. I can’t believe the fireworks these crazy old buggers have! They must have made a bootleg run up to Wyoming because most of the stuff I’m hearing and watching from my back porch is illegal in Colorado!

Good for them, I say. We are supposed to be celebrating INDEPENDENCE day, right? Life, liberty and the pursuit of happiness, right? Freedom? Seems like there’s less and less of all of the above every day.


More Oil Cooler & Fresh Air Intake

I finished fabricating the oil cooler hoses this morning. I read an internet post recently where someone said he considered the orange fire sleeved hoses ugly. I think they look pretty cool, actually. I think it’s worth it to buy the proper stainless steel bands and the banding tool rather than using safety wire. I also whip up my own firesleeve dip by mixing high temp RTV with lacquer thinner. I made a post showing how to do this a few months ago. It works great, looks great and costs a fraction of the real deal dip.

The hoses installed looking from the right side of the engine. I did a brief engine run with my EAA tech counselor standing by to watch for any leaks. Good news. No leaks. I’ll need to spend a little time tying the hoses down and doing a little chafe protection before I fly the airplane again.

I bought this nifty little tool from Harbor Freight for less than $40. it cuts through fiberglass like butter and because it vibrates rather than spinning, it hardly throws any dust at all. Wish I would have discovered this much earlier in my project. I cut a block of foam and glued it to a flat 3-ply sheet of fiberglass I had laying around from a previous project. This will be the starting point for my oil cooler cold air inlet plumbing.

I rounded the corners of the foam block and then attached it to the face of my oil cooler. I bought a 1-1/2 foot length of 1-1/2″ PVC pipe from Home Depot. I’ll use the pipe as a mold for my fiberglass cold air intake system.

I used modeling clay to make the transitions from the PVC pipe to the foam block and to my cylinder intake plenum. I put a thin coat of clay over the foam block. With a little mold release on the clay, it leaves a very nice, smooth finish after the layup cures and the clay is removed.

A birds-eye view of the cold air intake system. If necessary, I can add a few vanes inside the plenum intake to direct air to the cooler. I think it’ll get there without the vanes, but I guess it’ll be a matter of degree–as in how many degrees the setup lowers my oil temperatures!

I covered all the clay and the PVC pipe with Part-All wax/mold release. I then laid up 2-3 layers of 6 oz. cloth over the mold. Since it would be somewhere between difficult and impossible to layup all sides of the mold with it still attached to the engine, I decided to do what I could and then finish the layup with the parts on my workbench. I’m hoping I did enough glass work today to solidify the shape so that I can remove it from the engine and finish the layup tomorrow.