Saturday, September 22, 2007

$100 Hamburger - Springdale Airport, AR (KASG)

The Springdale Airport (KASG) is very nice. They have a tower, ILS, VOR and GPS LPV approaches, well maintained runway, and a recently paved ramp. The FBO runs a good business with lots of transient traffic including mid-sized jets, turboprops and high-performance pistons. The tower crew was friendly and are use to working aircraft not familiar with the area.

Pnnacle Air FBO
The FBO staff is eager and helpful. They will assist with anything you might need, but they do tend to get a bit overwhelmed if they are busy. The fuelers and ramp personal are young collage kids; however, they seem to hire people that want a future in aviation not just a summer job.

The staff was excited to see our Mooney and asked a lot of questions about it. They were also very careful fueling the plane. They followed proper procedures, they used a bonding cable, they covered the wing with a scratch mat without being asked, etc.

Springdale Airport Cafe
Springdale Airport Cafe is clean and has a good view of the ramp as long as you sit at a window that isn't fogged over. They have a nice outdoor sitting area as well. The food was ok, but the water is horrendous. Stay away from the ICE tea, coffee or water.

The restaurant also runs in their own time. They often close without notice. I highly recommend calling ahead (479-756-3339) before planning a $100 Hamburger trip; however, there is still no guarantee they will be open when you arrive. They appear to serve more breakfast than lunch. The chances of getting served are probably better in the mornings than afternoon.

Recommendation -- 3 Stars

I rated the overall experience at KASG 3 out of 5 stars. If it were not for the top service at the FBO and the excellent facilities, they would have been rated a 1 or 2. The downward rating is primarily due to our experience with the restaurant, which was the primary reason we chose Springdale as a stop in the first place. Here's what happened...

On our way out to the MAPA convention in San Antonio we stopped on Wed about 1:30 pm. They were open and only a couple of tables were occupied. The service wasn't overly friendly, but we got our food fast and it was decent. However, when we returned on Sat we arrived about 1 pm and they were closed! They locked the door and would not let anyone in. Turns out the son of the owner broke his glasses, so she closed the entire restaurant -- even though we called ahead and they knew we were coming! The owner was very rude when I asked to get something quick. She said, "she is the owner and can close the restaurant anytime she wanted to."

The Springdale Municipal Airport is an excellent quick stop. However, if you are traveling cross country with hungry passengers I would not count on the restaurant being open when you get there. Calling ahead certainly helps, but the owner clearly does not subscribe to the "customer is always right" philosophy. Unlike the FBO, the restaurant seems to cater more to the local drive-in than transient fly-in customer.

Wednesday, September 05, 2007

Baffled About Baffling

The Mooney is a fast airplane because every component was carefully optimized for speed and efficiency. The engine cowling, like most airplanes, is the one area that generates more drag than any other part of the airframe. The Kerrville engineers, which was led by Roy LoPresti at the time, did everything they could to design the 252 cowl with a low drag coefficient while continuing to supply ample cooling air to the engine.

The LoPresti Team did a great job with the 252. It is well known for being one of the coolest running turbos ever. However, it is critical that ram air flows through the front of cowl and over the cylinders properly in order to adequately cool the engine. If the air does not flow over the cylinders as designed they will eventually over-temp, which will lead to cracked heads, burnt exhaust valves, and an increased risk of catastrophic in-flight failure!

Care must be taken to keep the cylinders cool at all times, which is why I installed a JPI EDM-700 engine scanner right after getting 36G. The original factory temp probe is a joke. It is only connected to one cylinder (#4 in 36G's case) and not very accurate. The JPI is connected to each cylinder and records into memory what was going on with the CHT and EGT whenever the unit is powered up. Even if the pilot does not notice the high temps, the EDM-700 will. The data is easy to download to a PC that can be analyzed later. As far as I'm concerned, no high-performance airplane should be flying without one of these -- especially a Turbo!

I was noticing on the last flight that the #1 cylinder was running hotter than the rest and I had to open the cowl flap a bit to keep the CHT temp below 400 degrees. The outside temperature was not outrageous, so this was concerning to me. When you see CHT temps climbing in normal cruse, you need to pay attention to it.

It didn't take long to identify the root cause of the heat problem...

As you can see in the photo, the metal baffle seals are solid without cracks, but the black rubber is deteriorating. Properly functioning baffles need to form a tight seal against the cowling in order to force air to flow over the cylinders. If the baffling is not sealed properly, the air will take the path of least resistance and flow through the openings instead of around the cylinders. Inadequate baffling will also increase drag by allowing more air to flow into the engine compartment than needed.

Baffles are often overlooked. They are on every air cooled airplane, but you generally can't even see them until after the cowl is removed. Typically most owners never remove the entire cowl -- except for annual engine inspection. When the cowling is disassembled, mechanics and owners alike often focus more on doing whatever it is that motivated them to open the clamshell instead of looking at the baffles -- this is especially true of a Mooney since it can take an hour plus to strip a cowling. The end result is that there are many airplanes flying with inadequate cooling to some, or all, of their cylinders.

How to Test Baffles
The only effective test is to check the seals while the cowl is on the plane. It isn't easy to test airflow, but most everyone has a portable light. What I do is put a bright light into the bottom of the cowl (usually through an exhaust opening) and look through the front opening (where the air comes in) in a dark hangar. Properly installed baffles should entirely block the light around the edges of the seals. If you can see any light, they are not sealed properly.

36G failed the light test, so going in I knew I was going to have to replace the seals. I also knew that like many other near 20-year old rubber parts, they were simply past their lifetime and needed replaced. The decision was clear, I had to replace the baffles.

What Baffles Should I Use?
Baffles are generally custom fitted to the cowl and they are one of those strange category of parts that are on the engine, but considered an airframe not a powerplant component. Mooney doesn't sell them since they custom made them during assembly, Continental doesn't sell them since they are not an engine part, you can't find used ones, etc.

In most cases, a mechanic will buy a roll of baffle seal and trim it to fit. I don't like the generic rolled baffle seal because it deteriorates after a few years. It is also very difficult to cut the seals and come out with a good fit and finish. Most replacement baffles look like they were made in a garage. This is unacceptable for 36G's extreme makeover. I only want the very best. There had to be another option...

I noticed at Oshkosh this year that the Lanceair, Mooney and Cirrus use a top of the line rubber seal that has fabric woven into it. The big engines they mount on those guys need to stay cool, so they use a very efficient cooling system that is designed to handle the high heat and stress of the big boar engine. This material is perfect for 36G; however, the little 210 HP TSIO-360 does not have the same cowl configuration as a Cirrus! My goal was to find a supplier that sells the material so I can customize it for 36G.

It took some poking around, but I found it! A company called Sacramento Sky Ranch sells the material by the sheet. You can buy it, use the old seals as a template and cut away! This was a good find; however, as I was looking around I found a company called Gee-Bee Aero Products that is run by a Guy Ginbey. They are a small shop, but what they do is take the raw material and laser cut it to specs. Guy has traced a ton of engine baffles and has the templates already in a computer. This is a perfect fit for our 36G makeover.

Guy at Gee Bee is a super nice fellow, but they don't have a website. You have to call him or email. They can be reached at 800-556-3160 or via email at Guy isn't always around to answer the phone, but he is generally very responsive if you leave him a voicemail or send an email.

Installing Baffles
The first step in the process is to remove the old baffles. This can often be easier said than done. In 36G's case, the baffles were stapled onto the metal heat shields. The key here is to slowly and carefully remove the staples. Start working from the back to open them up and then work them out from the font.

An alternative to prying staples out with a screwdriver is to cut them with a heavy duty wire cutter or tin snip. I don't like doing it this way because it is very easy for one of the small pieces to get somewhere it shouldn't. If care is taken, however, cutting the staples saves a ton of time.

Care should be taken not to destroy the old baffles. You may need to use them as a template. I also mark them in 1, 2, 3, etc. order so I know where they were mounted. This makes the task of laying out the new baffles a breeze.

After removing the old staples and baffle material, the area should be throughly cleaned and checked for cracks. Any cracks should be stop drilled, welded or the piece replaced.

Then the new baffles need to be laid out to make sure that they will fit properly...

After verifying that all will fit, it is time to install them. You cannot be too careful here. This is a measure 10 times drill once ordeal. When the baffles start going on there is zero room for error. You can't make them longer and they are custom cut to fit with no spare parts.

Mounting the seals is an easy process. You simply secure them with pop rivets and metal washers. Care must be taken at this step to not drill into something you shouldn't!

After they are all mounted, the next step to to seal the joints with a high-temperature RTV sealant. Any locations not sealed correctly will leak, so I use a good RTV and clamps to hold the pieces in place until they dry.

The final product is significantly better than the original factory seals. It is easy to care for, durable and will likely last for another 20+ years.

Saturday, September 01, 2007

How to Change the Oil in a Mooney

Changing the oil is not the most exciting of topics to write about; however, I've learned a few tricks over the years that may help someone...

Mooney's designed their cowls to be tight. There is basically no way to change the oil without completely removing the top and the bottom cowl clam shells. It takes about 30-45 minutes to remove the cowl from a Mooney! This is a pain, so when I do it...I do everything I can while I'm in there.

Changing the Oil
The first step is fairly drain the oil. 36G has a quick drain plug, which makes oil draining a snap. You simply hook up a hose to the connector and open it. A trick to this is to run the engine before draining the oil. I typically fly the plane somewhere and then I drain the oil when I get back. The oil will drain much faster if it is warm. Another trick is to let it drain overnight. The more old oil that drains out of the engine the better. Don't rush this step. Let it drain completely.

After the oil is drained, the next step is to cut the safety wire and then remove the filter. Care must be taken when removing the filter. They are made out of thin metal. I highly recommend using the proper tools to remove the filter. You do not want to crush it by turning it by hand or a standard wrench. They can be nearly impossible to get off if they start to tare. It will also make a huge mess.

I have two different types of filter wrenches. The one above can be turned by hand and attached to a socket set. It works well for most conditions. I also have a special filter ratchet wrench for difficult ones. These tools are available just about anywhere that sells aviation parts.

Removing the filter always makes a huge mess. You need to be prepared for this so oil doesn't soak your tire. I wedge some old towels over the tire and other things I don't want oil soaked, then hold a bucket under the filter when I start removing it. Another trick I've used in the past is to use a old milk jug. You can cut the bottom out of it and leave the cap on. A milk jug is easy to cut and can be trimmed to fit around the filter catching the oil as it spills out. The filter can spin off and drop right into the jug. Take it to your drain bucket and open the cap. The oil will drain out without a drop getting on the floor.

After the oil is drained and the old filter is removed, the next step is to install the new filter and safety wire it. Care must be taken to safety wire this properly. You do not want it to spin off in flight. The safety wire should be pulling toward the tightening direction. So if the filter tries to spin off, the safety wire will stop it. A leak at the filter can quickly dump your oil overboard. Do not forget this step!

The final step in the safety process is to turn the end of the wire toward the can. It is very easy to cut your hands on safety wire, but if you turn the sharp edge in this will not happen.

The next step in the process is to make sure your oil drain is closed and to start filling the sump. A old mechanic trick is to pile all of the oil you intend on using on top of the engine. It is very easy to get diverted and forget how many cans of oil have been put into the sump. The oil filter, hoses and other components hold oil after the engine is run, so the dipstick is not reliable at this point. It will actually read higher until you run the engine (e.g. stick will indicate 7 quarts when it's actually 6).

After the oil is installed, the final step is to run-up the engine and then carefully inspect it for leaks. You will likely smell some burning oil when the engine gets hot. This is normal. Residual oil gets on the exhaust and other areas, but it will burn off in a few minutes. This step, again, is very critical. Oil changes seem simple, but people make mistakes. You need to check, and recheck to make sure that you are not leaking oil before returning the airplane to service. An engine can seize in a matter of minutes if a material leak develops.

Oil Analysis
Changing the oil is a good insurance policy. Aircraft oil is designed to hold and carry contaminants in suspension. The more particles the oil holds, however, the more abrasive the oil becomes. Dirt, Rust, water, etc. in the oil will slowly sand the inner parts of the engine and can also block oil coolers and other key components.

I highly recommend sending an oil sample at least once per year to a lab for processing. Labs use advanced equipment to detect very fine debris in the oil and identify them. For example, a high silica level would indicate that dirt is getting past your air filter. High iron, indicates that the metal parts in the engine have been sitting around without oil on them and rusting.

There are several labs that do this type of work. I have recently been using Blackstone Labs in Fort Wayne IN. They were a top pick by Aviation Consumer, so I thought I'd give them a try. What I like about Blackstone is they not only send you a report, but they write a personal note describing their findings. They will tell you if the iron or other components are high and what component in the engine is likely generating it. They will also show your engine sample and compare it to other like engines. I like this because I can see how I'm doing. Are we better or worse than other TSIO-36o's? Blackstone will let you know.

Open the Oil Filter
Lab analysis is very important, but equally important is opening up the oil filter and see what it has caught. An oil analysis will not tell you that a gear tooth chipped and fell into the engine, but the oil filter will probably catch it.

Opening a filter is a bit easier said than done. You can't just cut it with a hacksaw. You will generate metal from the filter itself, thereby contaminating your sample.

The first thing you need is an oil filter cutter. there are several on the market, but they are expensive. I like the AirWolf Filter Cutter pictured above. It isn't cheap, but it is high-quality and works well.

The oil filter cutter works about the same way as a plumbers pipe cutter. You slowly turn the filter cutter around the filter and then turn a blade knife a bit at a time. This causes pressure on the filter outer hull and will make a clean cut.

After the filter is apart, you want to first visually inspect the filter for large objects. Then you need to run a magnet around the filter and in the oil that spilled out looking for metal. You may find some hard pieces in the oil that are normal carbon buildup, but you should not find any metal. Metal large enough to be caught in the filter means something major is coming apart in the engine. Do not ever fly a plane if you find metal in the filter!