There are several ways of repairing worn cowl surfaces. Epoxy fill is sometimes used for minor wear, or flush or double flush riveted aluminum doubler plates can be formed and installed over the damage. McFarlane has a high temperature (400deg F) sandable two part epoxy with an aluminum filler that works well for filling minor cowl skin defects; please see P/N 20 GLUE KIT. Consult with your A&P mechanic for the best repair solution for your aircraft.
There is not a concrete answer that will work for every customer; it really depends on each individual installation. As a general rule, as long as you do not put the rivets at the very edge of the material it will not rip out. If you use McFarlane’s retainer strips, they can line up the edge of the material with the bottom of the retainer strip and then put the rivets in the middle of the strip.
Bi-Flex Cowl Saver can be adjusted for maximum stiffness across the gap between the engine baffling and the cowl. If you have a large gap, you will want to extend the un-scored portion out closer to the cowl so that the stiff un-scored part of the Bi-Flex Cowl Saver is bridging the gap. The stiff un-scored material will prevent air pressure from blowing the Cowl Saver out of position. If the gap is small between the engine baffling and the cowl surface, reduce the amount of un-scored Bi-Flex Cowl Saver extended across the gap. This will give you maximum flexibility for the best possible seal. After adjusting the Bi-Flex Cowl Saver position for the right amount of un-scored material in the gap, trim away any material extending more than 1/8 inch from under the retainer strips.
The Cowl Saver material drastically reduces the engine vibration that is transferred from the engine to the cowl and airframe. This is especially noticeable on the Cessna 185 aircraft with the large IO-520 engines. However, refer to the question regarding FAA-PMA approval.
It is certified to meet AMS3320G, which is the same industry standard specification to which other fiberglass reinforced silicone baffle seal material is certified, however it is not an STC or FAA-PMA product. It is ultimately the installing mechanics responsibility to determine whether the material is appropriate to repair the baffle seals on a specific aircraft.
McFarlane does have FAA approved die cut baffle seal kits for the re-start Cessna 172 aircraft; please see P/N BSC-KT-1. We developed this first because our patented material solves the firewall crack and other baffle seal related problems on these airplanes. McFarlane will develop more FAA approved baffle seal kits as engineering time permits.
Yes. Cowl Saver is stiffer than most cowl seal material in the un-scored condition. Bi-Flex Cowl Saver can be adjusted to better bridge the gap between the engine baffling and cowl surface. See the question “How much Cowl Saver material goes above and below the rivets?” for more details.
McFarlane recommends the Bi-Flex laser scored Cowl Saver baffle seal material for aircraft that have fairly straight baffling and cowl lines. There is no strip baffling material that works well for sealing a curved cowling. You can cut wedges out in the strip and stretch the outer edges or overlap it, but the best fit for a curved baffling is to cut a curved piece out of a flat sheet. Many customers order both the Bi-Flex roll and a flat sheet to give the best and easiest installation possible. You will then have enough material to do several airplanes.
Use of a deep throated hand squeezer will make installation using one hand easier. Always adjust the rivet squeezer for the right rivet height when the squeezer is closed all the way. This gives you maximum squeezer leverage and ease of use.
McFarlane manufactures a patented, Teflon-bonded, reinforced silicone rubber baffle seal material that gives you 30 times less friction on one side. Bi-Flex is our trade name for the laser scoring of this material to give maximum flexibility only where it is needed. For more information, please read Customized Flexibility for Optimal Cooling.
Yes, Bi-Flex costs 25% to 50% more for the extra processing and it will take a little longer to install, but this cost is small compared to the cost of cowling repairs and other damage from the engine movement that is transferred into the cowling and airframe. You will see a drastic reduction in cowling wear, cracks, and fastener fretting. You will also see a lot less cracking and damage to the metal engine baffles.
McFarlane uses a laser to score the Bi-Flex Cowl Saver material to approximately 40% of the strip width. This works well for assuring a great air seal when you have straight or minor cowl shape changes. However, where you have a curved baffle and cowl, you will get a better fit by cutting out curved pieces of Cowl Saver from a flat sheet and then custom scoring the Teflon on the outer edges for the flexibility you need. You can score Cowl Saver with a sharp razor blade or knife. The TOOL120 scoring tool makes several scores at once and is designed to prevent cutting too deep and damaging the fiberglass reinforcing in the center of the material. The job will go much faster with use of the tool. Even with the pre-scored Bi-Flex, you may find situations where some additional flexibility by custom scoring is helpful for the best possible fit. For more information, please read Customized Flexibility for Optimal Cooling.
No, D A M does not have any ammonia or other strong chemicals that could attack or shorten the life of any plastic. D A M has a very small amount of alcohol (less than .3%) in a water based solution. The quantity is so small that it has no effect on plastic or other surfaces. D A M is safe on all surfaces.
The polymers and carnauba wax in D A M window cleaner lubricate and encapsulate the abrasive dust and dirt particles so they slide on the plastic surface until they are absorbed deep into the wipe-off towel. The dust and dirt particles are still there, but they cannot get a damaging grip on the plastic surface. After the D A M cleaner is polished off it leaves a protective film that also helps prevent abrasion penetration of dust and dirt particles.
Never wipe a plastic surface when it is dry (or extensively while wet with just water) as some of the abrasive particles will be gouged into the surface, causing scratches.
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.
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.
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.
There are many different installations that were used for the different Cessna models. Please consult your applicable Service/Maintenance Manual and Illustrated Parts Catalog for the proper location for your specific aircraft.
We sell tool P/N 970 to facilitate the installation of the aft rollers and make the installation easier and simplified for this hard to reach location.
The handle of the tool makes access to the bolt hole in the small inspection opening easy. The pointed tool allows you to align the parts and easily insert the tool in the bolt hole. The next step is to push the tool back out of the hole with the bolt.
The Cessna Service Bulletin SEB95-3 describes damage to the flap support arms from the edges of the rollers cutting into them as the flap rollers rotate. Cessna fixed the roller end wear problem on the forward roller locations by installing a thin stainless steel wear washer between the roller and the flexible flap arms.
The aft roller location is more difficult as it is up in the flap structure and is rigid. The flap support arms will not flex open for the addition of wear washers like the forward roller location. The aft long roller position has the same wear problem as the forward roller locations. Since there is not room to install a wear washer with the existing roller, McFarlane designed a roller slightly shorter in length that allows room for wear washers on each end of the roller. The wear washers are designed with a step in them to make them an assembly that is easier to install.
Note that the upgrades do not change the aft narrow roller and shims/spacers that control the flap lateral end play. P/N MCSK100 only replaces the unprotected long aft roller(s) on each flap. Replacing the flap arms that have excessive wear is very expensive and time consuming. MCSK100 stops any further flap support arm wear.
Flap Roller Kits contain all of the rollers needed to complete one aircraft. Flap Roller Upgrade Kits include all of the components, forward wear washers (P/N MCS1450-3S10-032), aft service kit (P/N MCSK100), and hardware needed to replace the flap rollers and hardware associated with the rollers, along with Cessna SEB95-3 Rev. 1 for instructions to inspect flap support arms for wear.
P/N MCSK100 Flap Roller Service Kit replaces the aft wide roller assembly, and only the aft wide roller. Please consult your applicable Service/Maintenance Manual and Illustrated Parts Catalog for the proper location for your specific aircraft, and the STC SA01074WI.
A universal joint attaches to each control yoke shaft behind the instrument panel. Universal joints are very precision. Replacement of the universal joint is required if any free motion or rust around the joint pivots is detected or if the joint fails inspection required by the Piper AD 2010-15-10.
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.
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.
Yes. The fuel screen is removed by removing the standpipe. The rubber tipped plunger must be unseated before the standpipe is loosened. Failure to lift the plunger off of its standpipe seat can damage the plunger. Pull the strainer drain knob as if you were draining the fuel bowl. Block or clamp the knob in this position. Insert a smooth round tool such as a screw driver or punch in the standpipe cross-hole and un-screw the standpipe.
The fuel selector valve works in unscreened fuel. Contaminated fuel can cause selector valve seal damage. When fueling from possibly contaminated fuel sources McFarlane recommends the use of a fuel filter, such as Mr. Funnel or another filtering device, to reduce trash in the fuel system.
The most common indication of external fuel valve leaks is the smell of avgas in the cabin. Most valves are located under the cabin floor. Fuel stain on the valve and drain plug or drain valve or on the belly of the aircraft can also indicate external leakage. External leaks are generally around the actuation valve stem. Internal leaks are detected when the fuel is turned off and fuel continues to drip during fuel system maintenance. Inner port leakage will allow fuel from one tank to leak into another fuel tank. This type leak is difficult to detect. Fuel transfer from one tank to another with the fuel valve selected to one tank only will indicate inner-port leakage. An extended period of time is needed to detect fuel transfer from one tank to another. Generally if internal leakage is detected when servicing the fuel system, it is likely there is also inner-port leakage. A fuel shut-off valve can suffer from the same type of leaks as a fuel selector valve except that there is no selection of fuel source so inner-port leakage is not an issue.
Curtis Superior and SAF-AIR valves are designed for installation in a standard NPT port for NPT threaded valves or an AND-10050 style port for UNF threaded valves. Use a thread sealant or Teflon tape on pipe threaded valves. Never allow any thread sealant on the first thread . This will prevent contamination of the fuel system. Refer to aircraft manufacturer's torque specifications for the aircraft in which it is being used.
Replace the rubber seals as per the aircraft manufacturer’s recommendations or every ten years when no guidance is given. McFarlane stocks replacement seals and seal kits for both Curtis Superior and SAF-AIR valves. The new Curtis valves use a O-ring type seal instead of the flat seal that was previously used.
SAF-AIR valves are designed to be disassembled and the O-rings replaced. Over time, if the valve should start to leak, check to make sure the drain valve is tight. If drain valve is found to be tight, then check the O-rings. All O-rings used are buna "n", MS29513 Style, MIL-P-5315. SAF-AIR O-ring seal kits are available for most of their valves. Add a "K" or "-K" suffix to the valve part number.
Never have a hose attached in flight to the oil drain valve. Engine vibration and the additional attached mass can cause premature seal and valve wear which could result in valve failure and a loss of engine oil.
There are several other components in the fuel indicating system which could be the issue or are causing the indication problems:
Ensure that your aircraft fuel indicating system utilized Stewart Warner style transmitters.
Even if your aircraft originally came with that style, there were many Cessna Service Bulletins to replace them with the Rochester style. Our transmitters will not work with those components if they have been changed. This was a very common SB when Cessna switched over to Rochester.
McFarlane transmitters and Cessna Stewart Warner transmitters have an electrical resistance range of about 32 ohms when in the full position and 250 ohms in the empty position. This can be measured with an ohm meter connected between the wire terminal and the metal body. Note that the gold dichromate corrosion treatment on the zinc plating is a poor conductor. The metal body must be scratched a little to get a good electrical connection. The Rochester transmitter has a much different resistance pattern than the Stewart Warner or McFarlane transmitter.
Consult your log books and check the part numbers of the fuel gauges and transmitters. Do not rely on Illustrated Parts Catalog or eligibility.
With the age of most of the general aviation fleet, the possibility of corrosion in the wires or grounding is very likely. The gauge (indicator) may not be working correctly or properly calibrated.
Since the transmitter gauge system works with very low voltage and very low milliamp electrical flow it is very sensitive to proper grounding and high resistance in electrical connections. Most problems are related to electrical connections.
Excess resistance in the transmitter circuit can be detected by measuring the transmitter resistance with the transmitter being installed but without the wire connected at the terminal, and then measuring the resistance at the transmitter wire at the back of the gauge with the transmitter wire connected to the transmitter terminal and the transmitter wire disconnected from the fuel gauge and the other ohm meter connection to a ground at the back of the gauge. The resistance readings should be very close to the first resistance reading. In other words, you are measuring the transmitter resistance first without the airplane circuit and then comparing the reading with the airplane electrical circuit.
If the preceding wiring check shows good, the problem is likely in the gauge. The fuel gauge has a brass grounding strap that grounds the internal electrical coils to the gauge case. With years of service this grounding strap can develop a thin layer of corrosion that restricts electrical flow. When this happens the gauge will show more fuel than what is in the tank which is not good! Cleaning this ground strap should fix the problem. Refer to the Cessna service manuals for detailed trouble shooting and maintenance information.
Caution! Never short the battery power to the transmitter wire! It will take only seconds before the stainless steel resistance wire in the Cessna transmitter will glow red hot in the fuel tank. The hot wire could explode the tank! Never have power on when trouble shooting the fuel gauging system.
Do you have aftermarket Monarch fuel tanks installed? We have received customer feedback stating that when Monarch or other aftermarket fuel tanks are installed, McFarlane’s fuel vent line does not fit. There is nothing we can do to solve that issue. McFarlane’s fuel vent lines fit well when OEM fuel tanks are installed. Please review the Installation Tips for McFarlane Fuel Vent Lines.
The Viton gasket and screw seals do not require any sealer and must not have any lubricants. Do not over tighten the attachment screws as over tightening can extrude the gasket out from under the transmitter and tear the gasket in the screw holes. This will cause a leak. Tighten the screws evenly until you see the gasket just start to extrude a little. Any lubrication will aggravate the tearing of the gasket.
We pressure test our repaired valves to a minimum of 5 psi using precision controlled air pressure and a calibrated low pressure indicator. This pressure is above the normal fuel pressure on the valve and below the limits of the springs in the valve. Each valve is submerged in Stoddard solvent while the air pressure is applied to the valve. The valves are then tested in each position to assure that there are no inter-port or external leaks. Leaks are detected by looking for air bubbles escaping from the valve.
Over the years, there were some variations in the original vent lines from Cessna, and variations in the location of the exit hole in the wing. The vent line can be bent a little for proper fit. See the Installation Tips for McFarlane Fuel Vent Lines.
The SunSpot 36LX landing and taxi lights and SunSpot 46LX can be installed with just a log book entry if you can install the light in an existing mount and use the existing wires, switches, and circuit breakers.
The SunSpot 36HX landing and taxi lights and SunSpot 46HX can be installed with the pulse function enabled in any model listed on the AML under STC, or in other aircraft models with a 337 that uses the AML STC as a basis for approval.
If you do not know your serial number, you can just select your aircraft make and model.
The model you select must be specific: a 172 is not the same as a 172B.
Serial numbers must be complete: for example, 15073660 cannot be entered as 73660.
Hyphens in serial numbers are optional: for example, 28-7325001 and 287325001 are considered equivalent.
Due to the limitations of our product database, some parts that are eligible for your aircraft may not appear on the returned list of products when your aircraft make, model, or serial number is selected. If you can't find what your looking for, please call or email us.
Due to the possibility of error in eligibility data and the possibility of non-standard aircraft configurations, McFarlane Aviation, Inc. cannot be responsible for application of our products. The user of the products must verify correct eligibility and function of our products.
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The Cessna steering system is an engineering masterpiece that is simple in function while allowing good directional control throughout the transition from flight to ground or ground to flight, even in crosswind conditions. A key part of this system is the steering rods. The steering rods are a spring loaded device that applies spring pressure to pull on one side of the nose gear when it is activated and yet have a specified amount of free play in the opposite direction until a solid push is required for positive steering.
The following are some common symptoms of worn out or failed steering rods:
Weak steering (You can push on the rudder but not much happens and you have to use a lot of brake to steer. Often the weakness is one direction only.) The early Cessna steering rod springs were designed such that if the rudder pedal was pushed hard in one direction while the nose gear was pointed all the way the other direction and had some resistance to moving such as soft ground or snow, the spring could be compressed to an extent that it would be permanently shortened leaving it weak. McFarlane has redesigned the spring so this cannot happen.
More or less than 1.2 inches of free play movement or inconsistent free play of the steering rod shaft is present. The spring is retained by a washer that was stop swaged into the steering rod housing. During an overload, such as extra hard pedal force applied with the nose wheel pointed all the way in the opposite direction and restricted or undetected damage from a previous hard landing, the spring retaining washer can be deformed and forced past the swaged stop. This will result in inconsistent free play and erratic function of the steering rod shaft as the washer passes past its designed swaged stop in both directions. The rudder rigging in flight might also be inconsistent. This is a dangerous situation that results in inconsistent steering and the steering rod must be replaced. McFarlane has redesigned the washer and shaft machining to prevent the washer stop failure.
Rust and corrosion can make the steering rods unreliable. The steering rods get water and contaminates from the runway that the nose tire throws at them. The fit of the shaft into the bushing that is swaged into the housing is not a precision fit. This can allow internal contamination, moisture, and salt that will rust the springs and steel housing interior, leaving the components weak and subject to failure. Red rust streaking on the shaft exit area or bubbling of the exterior paint indicate corrosion failure. The McFarlane steering rods are made from 304 stainless steel and have a special corrosion preventative and lubricating coating on the springs to fight against corrosion and wear.
Wear of the shaft and bushing is caused by steering movement and aerodynamic pulse vibrations created by the rotating propeller. This wear can be detected as looseness of the shaft in the end bushing. Some wear is acceptable.
No. A little drag is expected and normal on a new McFarlane steering rod. The drag is caused by the thickness of the dry lubricant painted on the spring rubbing on the shaft. The drag is actually a good thing as it prevents vibration wear and will go away as the dry lubricant is worn in. The drag is acceptable when the weight of the spring and housing overcome the drag when the steering rod is held vertical by the threaded shaft.
We have seen torn brackets on the rudder bar torque tube cause lose of rudder motion and steering movement. The earlier Cessna airplanes had less reinforcing of the rudder bar torque tubes where the steering rod attachment brackets are welded on than the later model airplanes. An overload of rudder pedal pressure or prior nose gear damage can cause failure of the bracket attachment. Inspect all of the rudder and steering system when poor steering authority is detected.
Wheel pant mounting plates commonly crack around the axle. If any cracks are present, they should be replaced. The cracks are caused by wheel pant vibration. Assure that the wheel pant axle bolts are tight. Proper wheel balance will lessen wheel pant vibration. McFarlane's wheel balancers can help solve this problem.
Strut seal leaks and flat struts can be caused by roll or twist of the main O-ring seal. It is very frustrating to carefully check all the parts and surfaces and put a new seal kit in the strut only to find it flat again after a relatively short time. We have seen this happen when a film of MIL-5606 hydraulic fluid dries out on the exposed chrome strut shaft. MIL-5606 by nature has a tendency to get sticky as it is exposed to air and dirt and then dry.
Very slight dried oil films are sometimes hard to detect and they can get past the plastic wiper seal. When this happens the sticky strut has a tendency to grab the O-ring and roll or twist it when the strut slides in or out causing the seal to distort. A very small O-ring twist or distortion will cause a leak. This phenomena is aggravated by the low pressure that the Cessna strut is designed for. Wipe the chrome strut down with Stoddard solvent (mineral spirits) periodically to soften and remove any dried oil film, dirt, dust and bugs.
Rain will reduce the life of PROP GUARD as the constant impact of the water droplets will eventually fatigue the material, causing it to become more brittle with progressively less ability to absorb energy. This constant water hammering will eventually cause it to shred, starting at the prop tip area. This is a harmless situation that causes no concern in flight, but it will require repairing the PROP GUARD installation. PROP GUARD will tolerate a considerable amount of light rain, but fails fairly quickly in heavy rain. When PROP GUARD is failed by rain, it has already sacrificed itself to prevent considerable propeller erosion.
Although PROP GUARD has been successfully used by some customers on non-certified aircraft with composite propellers, it is not FAA approved yet for applications not listed on the FAA Approved Model List.
PROP GUARD will stop water erosion of the propeller and has been used on seaplane applications. However, it has very limited life on high speed propellers that are subject to a lot of water spray. Water spray will reduce the life of PROP GUARD as the constant impact of the water droplets will eventually fatigue the material causing it to become more brittle with progressively less ability to absorb energy. This constant water hammering will eventually cause it to shred, starting at the prop tip area. This is a harmless situation that causes no concern in flight, but it will require repairing the PROP GUARD installation. Some seaplane operators use PROP GUARD knowing that they will have to frequently replace PROP GUARD at the prop tip area. By sacrificing itself, the PROP GUARD has stopped considerable prop erosion. PROP GUARD will hold up relatively well on lower horsepower applications where the propeller has good water clearance.
PROP GUARD is not certified for use on certificated wooden propellers. It can sometimes be used on non-certified aircraft applications. Some varnish used on wooden propellers is not compatible with the PROP GUARD adhesive and the bond will fail. PROP GUARD has been successfully used with many varnishes. We recommend testing by placing a small sample of PROP GUARD on a surface with the same varnish before installing on a propeller.
Follow the guidance of the aircraft or propeller manufacture. When no guidance is available, conversion coating such as Alodine followed by a light coat of corrosion preventing primer followed by the finish coat has proven effective. Before you start, be sure the metal is clean and use a silicone removing compound such as Naphtha or a commercial wax and silicone remover with multiple clean paper towels to assure all traces of silicones have been removed. Most solvents will not remove silicone compounds.
The first installation takes longer, with reading the instructions and carefully going through each step. You always want to properly dress the propeller before you install PROP GUARD as this is the last time you will need to dress or paint the prop until PROP GUARD is replaced. First time installation on a properly dressed and painted prop takes close to an hour, and about fifteen minutes once you have done several.
PROP GUARD is a very special high strength product manufactured to take the high centrifugal forces of the rotating propeller while being able to absorb impact energy. It goes through special heat treatments and careful quality controls. Only some of the material manufactured will pass our rigid quality standards. PROP GUARD is different.
The problem is most likely caused by silicone contamination. Any trace of silicone compounds will act as a release agent and destroy the bond of the underlying paint or PROP GUARD adhesive. Silicone cannot be removed with lacquer thinner, MEK or other standard solvents. Naphtha or a silicone remover found at local auto parts or paint stores is required to remove it. Just repainting and reinstalling will probably not solve the problem. The silicone contamination can come from something as simple as touching the prop with your hands that have touched RTV or a waxed surface.
There is no loss of performance for the listed applicable model propellers. We have seen some performance degradation on exotic high performance experimental applications where extreme prop speeds or extra wide propeller blades were involved. We have also seen some experimental use of PROP GUARD where there were performance increases when the PROP GUARD edge was pinked on the face (forward side) of the propeller. The zig-zag pattern of the pinked edge produces a vortices generation that helps hold the moving air to the propeller surface longer.
There is a certain size rock that will break through the PROP GUARD and damage the propeller. When this happens, the damage to the propeller will be much less than if PROP GUARD had not been there, as much of the rock’s energy is absorbed by failing the PROP GUARD.
However, any paint that is specifically designed for plastic should work on Premier parts, which are manufactured with a PVC-Acrylic material commonly referred to as KYDEX. Retail stores that sell automotive paint can be helpful with paint choices as most of automobile interiors are made from KYDEX also.
The laser marking does not harm the hard durable anodize coating on the aluminum knob. The CO2 laser process only bleaches the color from the anodizing leaving a silver white color that contrasts with the surrounding dyed anodize. The durability of the laser marked area is not affected by the laser. Our tests have shown that the laser process actually improves the corrosion resistance of the anodize layer. The CO2 laser engraves the hard plastic knobs by vaporizing the surface leaving a deep durable groove. This groove is then filled with a special paint for contrast. The result is a durable long lasting mark.
McFarlane's Storage and Packaging Specification requires a specific packaging minimum radius based on the length of the control, type of wire used, and the configuration of the control end(s). Please contact us to determine the exact requirements for your specific control.
There are several things that could be different such as engine/aircraft modifications, rigging/clocking of control arm or adjustment of rod end will be needed, placement of clamps or brackets may be different, or a previous installation change such as routing from original.
On some aircraft (like the Lycoming IO-540 engines) the induction box covers up the oil pan where the SAFE-HEET would normally be installed. It is permissible for the SAFE-HEET to be installed on the induction box, because the box/plenum is a thick casting that can transfer heat effectively.
SAFE-HEET engine heaters are installed with a two-part adhesive. The engine heater can be installed quickly and easily by using the 707 temperature controller at half power. At temperatures below 70°F the temperature controller must be used to ensure proper adhesive cure. Proper adhesive cure is essential to full service life of the heater.
The amount of adhesive contained in each kit is enough to do one installation and offers better thermal heat transfer than using a larger quantity. The adhesive should be thin, if there is no adhesive 1/8” from the edge of the pad it will not be a problem because our adhesive is totally resistant to solvents or oils. Sealing the edges is not necessary. Using silicone adhesives will allow the heat pad to come loose because silicone is not resistant to solvents or oils. If you feel you need more adhesive, we will send you more at no charge upon request.
Reference the troubleshooting instructions provided with the purchase of a SAFE-HEET. The GFCI will not work unless plugged directly into an outlet. Plug in the GFCI then the temperature controller. The GFCI needs to be the first thing plugged into the circuit. The GFCI needs full voltage to engage. It cannot have an extension cord plugged in the outlet, then the GFCI to the SAFE-HEET. The GFCI does reset itself every time it is unplugged.
McFarlane’s adhesive is thermally conductive, so it transfers heat effectively while the other brands use a peel and stick tape that tends to fall off. As a result, McFarlane’s has a longer life over the other brands. McFarlane’s adhesive is resistant to solvents/oils but if it ever does fail, the heat pad is not going to jam up anything in the engine compartment, because it is not a solid metal like other brands out there. SAFE-HEET heats the engine oil while other brands heat the cylinder, not the oil. SAFE-HEET is safe and is electrically grounded with a ground wire. The SAFE-HEET pad covers a large surface. McFarlane’s GFCI can be used with any heater, not just SAFE-HEET.
The kit includes the SAFE-HEET and temperature controller. The temperature controller makes installation easier and helps control condensation which leads to corrosion. It is like a dimmer switch that puts you in control of how much power is going to the unit.
No, McFarlane does not provide templates for installing seat rails on Piper aircraft because the rail is riveted to the floor of the airplane, making installation easy by riveting directly from under the airplane.
Aircraft make, model and serial number are not sufficient to ensure the correct replacement spring as many aircraft may have been originally equipped with either one or retrofitted with a conversion kit. If the spring you are replacing is marked with a brand name (e.g. P.L. Porter or Stabilus) the correct replacement is readily identified. The coil spring/hydraulic style are also identifiable by a 1¼" diameter visible coil spring. The thread may also be measured to verify the correct identification.
The screw kit depends on if the holes in the floor of your airplane have been carefully removed and are close to new size or if they have been enlarged by unskilled rivet removal or the rails have been changed before. It will make a difference if the previous rails installed were Cessna rails with predrilled holes in the rail. (They do not normally line up well and the floor has been mis-drilled some to force them to align). If the holes are good, use the SR6-SCREW-KT kit. If the holes are enlarged some, use the SR8-SCREW-KT kit.
Determine which extrusion is used: STE101 and STE102 - Standard hole depth drilled on the roller flange is .330” and standard diameter is .277”. STE103 and STE104 - Standard hole depth drilled on the roller flange is .280” and standard diameter is .277”.
When hydraulic oil changes temperature, the volume of the oil also changes. This volume change from a temperature reduction will create a vacuum in the oil chamber of the original Cessna uncompensated shimmy dampener. This vacuum will cause the oil to vaporize giving the oil a foamy expanded mixture that is compressible. The shimmy dampener action is then drastically degraded. An increase in temperature will increase the oil volume causing a drastic pressurization of the dampener oil chamber. This pressure will force small quantities of oil past the dampener shaft seals. The decrease in oil will then aggravate any temperature reduction with increased chamber vacuum and related oil vaporization. This process explains why continuous servicing of the original shimmy dampener is required.
The temperature compensation system works by having a small chamber of oil that is spring pressurized through a very small passage into the main dampening restrictive orifice of the shimmy dampener. The spring loaded oil chamber can adjust for oil volume changes as temperature changes. A similar system is built into your car shock absorbers. The temperature compensated hydraulic system requires very little service over extended periods of time and assures stable shimmy dampening action.
A rubber based dampener is continuously fatiguing the rubber components as it changes direction of motion. The rubber system depends on stable friction of the rubber riding in a metal tube. This is very difficult to achieve over extended usage. There are inherent differences in static friction of rubber and dynamic friction of rubber that affect dampening performance. Long term use changes the performance of the dampener caused by all of these un-repairable factors. The hydraulic system works in a film oil with stable performance for long periods of time and it is totally repairable.
Removing the flanged bushings from the torque link forging can be difficult as there is not a good surface to press against or grab onto. An easy way to remove them is to thread them with a tap, screw a bolt in the thread you made, and then drive or press against the bolt. The thread does not have to be a full depth thread for the bolt to hold securely in the bushing. The bushing material is somewhat hard, but not so hard that a standard hardware store tap will not do the job. Use cutting oil on the tap to prevent tap damage. Normally the bushing will then come out easily.
For stubborn bushings, soak the link assembly in boiling water before pressing the bushing. The heat will expand the aluminum forging more than the steel bushing. This helps loosen the press fit while limiting the temperature to prevent from overheating and harming the heat treat of the aluminum forging. A controlled oven can be substituted for boiling water as a heat source, but do not exceed 350° F. Do not use flame or other non-controlled heat sources.
An alternate method is to put dry ice in the bushing before driving or pressing on the bolt you threaded into the bushing. Do not over-press or hammer as the aluminum can gall to the bushing and leave a damaged bushing bore. If the bushing does not come out with light to moderate force take the time to use some heat or cold to help.
There are many components all connected to keep the nose gear in line. If one component is worn or out of tolerance it can cause shimmy problem. Reference Dave McFarlane’s article: Can You Stop Nose Gear Shimmy instructions and suggestions.
Overlooked items also include the rod ends, shimmy dampener mounting and attachment, shimmy dampener, and steering collar. The steering collar is where the steering rod tubes connect and the upper torque link is attached to, along with the shimmy dampener on most aircraft. If the steering collar has play vertically and laterally and is allowed to tilt; that will cause excessive wear and force on the torque links, steering, and strut components. There are three different thicknesses of shims to help get the collar in place.
Ensure that the shimmy dampener is working properly with no dead spots in dampening action. The cylinder could be worn on the inside or on a piston that warrants replacement of components. All of the nose strut components are tied to each other and any movement is transmitted through to the tire and back through the dampening system, which if remedied will continue to be more pronounced.
It is very important to maintain proper torque for the bolts that clamp the chrome bushing/spacer at the upper attachments to the steering collar and the lower attachment to the nose gear strut. It is commonly thought that the chrome bushing/spacer is kept in position by the bolt filling the center bore of the bushing/spacer. This is not correct as the inner bore of the chrome bushing/spacer and the bolt are a loose non-precision fit. The bushing/spacer is secured by the bolt end, clamping the spacer so that it is tight between the arms of the aluminum forgings. Any looseness of this end clamp will allow movement of the chrome bushing/spacer. This movement will erode the aluminum forgings and create more free motion of the torque link.
All shimming of the torque links must be done with proper torque on the bolts. Periodically and during nose gear inspections, check the torque on the upper and lower torque link bolts. If the chrome bushing/spacer is allowed to move, the resultant wear can require replacement of the expensive aluminum forgings. McFarlane is working on a repair for the worn aluminum forgings. Unlike our competitors, extra care is given to the machining of the McFarlane chrome bushing/spacers to give the largest possible bearing surface to the ends that bear against the aluminum forgings. Chamfers or bevels are kept very small.
The torque link stop lugs are more important than you would think. Overextension of the nose strut due to a worn out stop lug can lead to a cascade of problems. McFarlane A&P mechanics have seen struts over extend to the point where the metering pin comes out of the orifice. This results in loss of damping action and the pin hammering the orifice every landing and distorting and enlarging it. Over time, the excess nose strut travel and lack of damping can result in fatigue cracks in the torque link arms. McFarlane recommends thoroughly inspecting all nose strut components when replacing a severely worn stop lug.
The stop lug also acts as a centering device aligning the nose wheel and wheel pant straight with the airplane and slip stream after it has left the runway. Worn stop lugs can allow the nose wheel to lock in a turned position in flight that will require holding rudder for coordinated flight. Retractable gear aircraft depend on the stop lug to properly center the nose gear steering before it retracts into the wheel well.