A number of pilots have asked this question. The answer is a definite no. When Shell first started evaluating multigrade aviation piston-engine oils over 25 years ago, testing proved that multigrades formulated only with mineral base oils did not have adequate base oil viscosity (thickness) to properly lubricate all high load points in the engine. Then we tested and flight evaluated a formulation made with all-synthetic base oils.

This formulation had excellent antiwear characteristics in all tests run. However, in the flight evaluations, some engines would reach 600 to 900 hours, then lose oil consumption control and/or compression. When the engines were disassembled, we found that the piston rings were covered with a gray tacky substance that was primarily made up of the lead by-products of combustion (from the use of leaded aviation gasoline).

Although synthetics are excellent lubricants with good high temperature stability and very good low temperature flow characteristics, they are relatively poor solvents.

In an aircraft engine, the lead by-products of combustion must be dissolved by the base oil so they can be carried away from the ring belt area and removed from the engine when the oil is changed. Anticorrosion, antiwear AeroShell Oil W 15W-50 is formulated with 50% synthetic base oils to give it the excellent low temperature flow needed for quick lubrication during cold starting. 

The synthetic base oils, along with the unique antiwear additive system, give it antiwear protection unequaled by any other product on the market. In addition, its mineral base oils provide lead absorbency to guard against ring sticking and excessive sludge. The bottom line: The synthetic component of AeroShell Oil W 15W-50 will not harm your engine. Instead, it gives you the best of both oils.

Yes. The thickness, or viscosity, of an oil is directly affected by the temperature. Therefore, if an engine's oil temperature is increased, there will be a small, but proportional, drop in the oil pressure as well.

In most cases, the multigrade oil will run cooler. For a hot-running engine, like turbocharged, high performance or aerobatic aircraft engines, this is good, but for a cool-running engine it can be a disadvantage. If the engine runs too cool, it can't boil off excess moisture and unburned fuel, so there can be a tendency to form acid buildup. For cooler-running engines, pilots should use a winterizing kit, or check with their mechanics on how to keep oil temperature up.

Aircraft windshields and windows are made from a hard durable MIL standard acrylic plastic that has a long service life. However, they are still plastic and can be damaged if not cleaned properly. Aircraft windshields and windows are not only expensive, but changing them takes a lot of expensive labor. Paper towels are made from a matrix of processed wood fibers that can be hard enough to scratch plastic. Paper towels will not damage the acrylic every time they are used, but consistently using them will eventually give you little fine scratch defects that refract light differently than an adjacent smooth surface. The small differences in light refraction will obstruct and distort your view.  

Dust is made up of many little abrasive particles so it is important to isolate the dust particles from the windshield as you wipe. The softer and more expanded the cloth material is, the greater the tendency for the cloth to absorb the dust particles isolating them from the cloth surface. In other words, the dust particles can go deeper into a soft fiber matrix as compared to a harsh hard fiber matrix of paper towels. Dust and dirt particles tend to collect on the hard paper towel surface giving it a sandpaper effect. Gently feel a paper towel surface. Gently feel a T-shirt or micro fiber cloth. The surface hardness is very noticeable. 

In summary, there are really two differences in a paper towel and a soft fiber cloth. One difference is the hardness of the actual fiber and the second is the ability of the fiber matrix to absorb dust particles away from the fiber surface. 

When a straight mineral oil turns dark or black, it usually means that the oil is starting to oxidize and needs to be changed. Because mineral oil doesn’t absorb much of the dirt and sludge in your engine, the oil stays clean and the inside of your engine gets dirty. Ashless dispersant oils, on the other hand, are designed to get dirty so that the engine will stay clean. 

Just how quickly the oil turns black depends on a number of factors, including the condition of the engine, the dirt load, the oil temperature, the normal air/fuel mixture, the type of fuel, the time since the last service, and the frequency and duration of your flights. Basically, the important thing to remember is to change your ashless dispersant oil on calendar and engine time, not according to its color. Also, oil analysis can help ensure that the oil is still in good condition even though it may have turned black.

The high temperature inert dry lubricants are expensive to produce and refine. Since it only takes a thin film to be effective it is more economical than other anti-seize compounds. A can goes much further.

Scrubbing the window with your hand is most effective as the cleaner is not being absorbed by a rag. This process gives the cleaner time to soak into the bugs and dirt while distributing the cleaner evenly. A very small rag wet with the cleaner or a VERY SOFT bristle brush also works well. Wash your hands after you are done.

Yes. This can be very difficult on some aircraft, but it is recommended. The reason for changing oil when the engine is hot is to avoid the settling of dirt and water in a cold engine. When the engine is fully warmed, then drained, a higher percentage of contaminants are drained away with the old oil. When the engine is drained cold, more of these contaminants remain in the oil in the bottom of the pan, which results in more contaminants mixing with the new oil.

Over the years, a number of oils have come and gone. Most new products perform great in one bench test or another, or even in a short-term engine test. But loboratory conditions may not duplicate real world conditions. The best way to judge an oil is to see how it performs in actual service, under real world conditions. 

Some of these conditions may include sitting for weeks at a time, starting in less than ideal conditions, and flying on days that your mother would have told you to stay home. Oils with a proven track record, like AeroShell oils, can be counted on to deliver top performance year after year.

There are two types of cloth that work well to prevent scratching on plastics.

The first is the synthetic micro fiber cloth. This soft supple fine matrix cloth will do an excellent job of protecting the acrylic surfaces. The down side of this cloth is that it is expensive and the wax and polymers used in plastic cleaners do not wash out well. The microfiber cloth will have to be thrown away when the wax and dirt buildup prevents a streak free surface.

The other cloth that works well is soft cotton cloth, with the best construction being T-shirt material. The fluffed soft cotton fibers have layers that isolate dust and dirt well from the cloth surface and they can be used many times. The cost is low enough that you can just throw them away when they get contaminated.

First, if you’re “breaking in” your engine on mineral oil during the winter, always take extra precautions to ensure that the engine is properly preheated prior to flight.  For example, if your service bulletins recommend preheating the engine whenever the temperature is below 20°F, you may want to increase that to 30-35°F when using straight mineral oil. 

Another concern is that mineral oil is more prone to oil cooler plugging at low temperatures.  This is especially critical on aircraft used for high altitude flight where temperatures are even lower.  If an aircraft is going to be broken in during the winter or at high altitudes, you should consider using a winterization kit.  The kit will reduce airflow through the oil cooler and reduce the chance of oil cooler freeze-up.  (However, be sure to remove the winterization kit when it’s no longer needed.) 

During winter break-in and high altitude flight, pilots should also be especially observant of their oil temperature and pressure.  If the oil pressure or oil temperature moves significantly up or down in flight, you may be experiencing oil cooler plugging or bypassing.  If this occurs, you should take appropriate action.

Our Vertical Fin Fitting kits include all the hardware needed for installation. You may receive NAS1149 hardware with the kit, which supersedes AN960 hardware (referenced in our ICA).

Oil analyses can help you discover engine problems before they turn into major failures. But the analysis information gained is only as good as the sampling procedure. Also, a single test is not enough to reveal trends and significant changes and can only tell you if there is already a serious problem like a scuffed piston. Take oil samples properly. For best results, take the sample about midway through the draining of hot oil from your sump. 

A sample pulled off at the beginning or end of the oil change may appear dirtier than it really is. Sample the oil the same way every time. An improperly taken sample can lead to some seriously inaccurate conclusions about engine malfunctions. Rely on a series of consistent tests over time. You’re looking for significant changes or trends over time, not absolute values.

People want to label the results of a single test as good or bad, but the system doesn’t usually work that way. Say you’re buying a used aircraft. Don’t rely on just one very good result of just one report – it could have come from a 5- or 10-hour sample. Relatively constant numbers from the last six oil changes are a far better indicator that the engine is in good condition. Your record of regular oil changes and analyses is also helpful when selling an aircraft. 

Be consistent. If you change your oil at 50 hours, and then at 25 hours the next time, the first sample may show twice the wear metals. (Expect higher wear metals during break-in or following some maintenance procedures such as a cylinder replacement.) Finally, always remember that oil analysis should be part of a good maintenance programme, not a replacement for one.

Yes, low oil temperature can lead to excessive rusting and corrosion of critical engine parts. When an aircraft sits on the ramp or in a hangar, the engine heats up during the day and cools again at night. While the engine is cooling, some of the moisture in the air condenses on the engine walls and drops into the oil. 

This can form rust on internal engine components. The moisture can also react with by-products of combustion in the oil,forming acids which can lead to corrosion. The best way to remove this water is for the engine to boil it off during flight. Studies have shown that the temperature of your engine oil increases about 50°F as it circulates through the engine.

Therefore, unless the oil temperature reaches 170°F to 180°F during flight, the engine will not boil off the water that has accumulated in the crankcase. The result: rust and corrosion.

Note that an excessively high oil temperature will also cause problems. Here are some tips to help avoid oil temperature problems:

Check your oil temperature gauge for accuracy. It should read about 212°F when the sensor is placed in boiling water.

Monitor the oil temperature during flight. It should be about 180°F even in winter. If it is lower, you may need a winterization kit. Otherwise, check with your mechanic to see what is causing the excessively low oil temperature.

The unique additive feature in anticorrosion/antiwear AeroShell® Oil W 15W-50 can also help control problems caused by rust and corrosion.

The trim wheels on the Cessna 180, early 182 and 185 aircraft have a spring loaded trim wheel stop catch assembly that engages with a molded in ratchet on one side of the trim wheel. This system is designed to prevent unwanted trim wheel movement caused by air pressure on the horizontal stabilizer. If these stop catch assemblies are worn out, the trim wheel is free to rotate. McFarlane has replacement stop catch assemblies.

Clean the barrel and screw jack and re-apply a coating of MIL-PRF-23827 low temperature grease. The cam bushings that attach the jack screws must be properly adjusted so that both jack screw work as one unit. If the cam bushings are not adjusted correctly the jack screws can work against themselves causing a hard to turn situation. Please review the complete instructions.

 Only a thin film is required to be on the surface of both parts of the exhaust joint so the small can will service many more exhaust joints compared to a big can of pasty grease. 

Since D A M is a mixture of heavy dry lubricants and light petroleum distillates, it will separate quickly.  Shaking the can often during use keeps the lubricants in suspension. D A M works best when it is rubbed into the stainless steel. Rotation joints back and forth before final assembly will help imbed the dry lubricant particles into the stainless steel surface. Then disassemble and recoat the joint.

D A M window cleaner is a mixture of non-toxic wax, polymers, and a mild detergent with the slightest trace of alcohol. It is an irritant to the eyes if it has direct contact.  

No. Most of the metallurgy in the valve train of aircraft engines was designed to be operated on leaded fuels. Even 80/87 engines were designed for fuels with 0.5 gram per gallon lead.  Experience has shown that the lead level in aviation gasoline is especially critical during break-in. So, if you’re breaking in a new or an overhauled engine, make sure you use a leaded 80/87 or 100/130 low lead aviation gasoline for at least the first 50 hours of operation. Some fuel suppliers sell an unleaded 80/87, so make sure you're getting leaded gasoline for breaking in your engine.