Bondline - User contributions [en]

Auxiliary Fuel Tank

2022-07-14T15:46:15Z

Mdrahzal: Changed STC Holder

There is an STC for an auxiliary fuel tank for Grumman 4-seaters. It is particularly useful for the AA5, which has a 37 gallon fuel capacity in the wing tanks. The STC holder is Griggs Aircraft griggsaircraft.com.

The auxiliary fuel tank is an 18 gallon tank that fits in the baggage compartment. It is about 1 1/2 to 2 feet high and covers about 3/4 of the floor space in the baggage compartment. The fuel tank feeds the right wing tank.
The fuel transfer must be started manually and can be stopped manually or will stop automatically when the auxiliary tank is pumped dry. (It will not stop automatically if the wing tank is full. Extra fuel will be vented overboard.) A fuel gauge for the auxiliary tank and the transfer switch are mounted just forward of the position of the cigarette lighter on the console between the pilot and copilot seats.

It takes approximately 80 minutes to pump the 18 gallon aux tank dry.

If you have installed this STC, you must carry a copy of the Form 337 with you in the plane. Otherwise you are liable to have the aux tank disassembled if, for example, a customs or law enforcement officer wants to search your plane and see if you are carrying drugs or other contraband.

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[[Image:O&N_Tank_Side.jpg]]
View from Tiger Cargo Hatch

[[Image:O&N_Tank_Top.jpg]]
View from Front

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Interior Trim

2008-08-06T12:27:40Z

Mdrahzal: Added SEM Product Data. Updated URL for SEM Products

'''Mechanical Difficulty:''' [[Image:Wrench.jpg]]

To repair cracks and chips in the interior ABS plastic (AKA "Royalite") trim, the Maintenance Manual gives a procedure that I've had good success with. The MM recommends using [http://www.aircraftspruce.com/catalog/cspages/acsmek.php MEK (Methyl Ethyl Ketone)] solvent as a plastic welding glue. MEK is available at larger hardware stores in the paint department.

The process is to paint MEK on the plastic edges and allow the solvent to soften the plastic, and then press the edges together and let the solvent flash off, leaving a joint that is nearly as strong as the original material. To fill small voids a paste of ABS plastic and MEK can be prepared and painted on in coats to fill the missing area. Small brushes are recommended. A metal or glass container to hold the solvent is needed, since it will attack most plastics.

You can obtain a pre-made ABS paste from Lowes and other hardware stores in the plumbing section. At Lowes it's in a blue can and it says "ABS Cement" on it. If you look at the ingredients on the label it will say that it is ABS and MEK. There are also several plastic pipe cements in the same area. Beware of any that list other types of plastic such as PVC or CPVC, as these will be just solvents with no ABS filler included. The pre-made ABS cement is best applied after a coat of MEK to soften the base plastic. This gets the ABS of the base part ready to fuse with the ABS in solution.

With a little patience and some scrap ABS sheet, doublers can be fabricated to glue on the back of cracked and chipped areas, especially helpful to back up screw holes that have cracked out or lost a pie wedge of plastic between the screw hole and the edge of the part. These doublers adhere very well if you paint the back of the part with MEK and wait for the plastic to soften, and paint the face of the doubler, and then re-wet the area on the part where you want to bond the doubler and press them together wet. Some [http://www.pegasusautoracing.com/bigpicture.asp?RecId=1776 Cleco clamps] are helpful to hold the parts while they flash the solvent and solidify. Having the clamps lets you do several repairs without having to wait between each repair for the last one to become firm enough that it doesn't pop loose. Others have found that the cheap [http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92874 plastic spring clamps] from Harbor Freight or WalMart work well, with fairly large area, flat, self-aligning jaws.

ABS sheet and strips in small amounts can be obtained at your local hobby store - most carry the "Plastruct" brand [http://www.hobbylinc.com/htm/pls/pls90366.htm (typical stock)]. Note that their styrene is white, and that the ABS is grey... the sales person might refer to it all as "plastic".

After a doubler is bonded on the back and cured, you can fill the area where the chunk was missing by painting coats on the front side. Just as with paint, several light coats is much better than fewer heavy coats, and you want to let them dry between coats. After 2 coats it probably will need to sit overnight to allow the solvent to evaporate from within the layers. If you have filled the area sufficiently, then you can sand the surface to smooth it and level it with the surrounding area. Old plastic being reused may benefit from a small doubler of thin 0.020 ABS sheet at each of the attaching screw holes to prevent new cracks.

On really big projects, especially external parts like elevator tips or tail cones, you might need to apply a larger doubler or hold a big crack in alignment. You can use the ABS just like aluminum sheet and make doublers to go behind cracks and hold the doublers with clecos in a series of rivet holes. The holes can be filled later and the part sanded smooth before painting. Carefully done, parts that would have seemed unsalvagable can be returned to service and look just like new after sanding smooth and repainting.

The interior plastic trim can be made to look like new with a coat of "vinyl dye". This is just a paint that is formulated to bond to the plastic. There are several brands, some available in rattle cans and some available in bulk for a spray gun. Automotive paint supply stores that serve the body shops will be able to mix the bulk type in a rainbow of colors, and usually stock [http://semproducts.com/ SEM products]. Many auto parts stores carry the rattle can variety in a half dozen colors. In preparation for applying the vinyl paint, all the dirt, oil, and contamination that has accumulated on 30 years of service needs to be removed. Begin with dishwashing soap and water, and use a scotch-brite pad to scour the surface. Rinse with running water and let it air dry. Just prior to spraying, a wipe down with enamel reducer or a proprietary wax and grease remover such as [http://www.performancecoatings.dupont.com/dpc/en/us/html/prodinfo/chromasystem/H-19295_3919S.pdf#search=%22%22prep-sol%22%22http://www.example.com DuPont Prep-Sol] using a clean white rag will help assure that the paint covers evenly and is able to get a good grip on the substrate.

If you wish to go an "All SEM" rattle-can route, the following products have worked well. SEM 38353 Plastic/Leather Prep is an Propane/Isobutane/Petroleum Solvent product which is useful for wiping down the plastic parts to remove any excess oils. Next, a combination of SEM 38363 Sand Free and SEM 15103 Super White Color Coat gives a original-looking finish. Sand Free is an adhesion promoter which softens the plastic (Acetone/Propane/Butane) and allows the Color Coat to "melt" into the plastic. Follow the instructions on the Sand Free can closely - and the results are amazing. (If you are doing extensive refinishing, you will need three or four cans of SEM Color Coat Super White, but the Sand Free and Plastic/Leather Prep go a long way, so multiple cans are not required.)

Canopy Side Windows

2008-08-06T12:04:34Z

Mdrahzal: added details about the rivets needed to re-assemble canopy plastic

== Canopy Side Windows on the 4 Place ==

'''Mechanical Difficulty:''' [[Image:Wrench2.jpg]]'''-''' [[Image:Wrench3.jpg]]

'''Tip: Don't even THINK about doing this except in warm weather or unless you can move the canopy assembly to a heated room indoors. Its critical that the plexiglass temperature be at least a comfortable room temperature, and warm enough that you are sweating on it is even better.

=== Canopy Removal ===

The AA-5x canopy side windows slide in from the bottom, and that means that step one is to remove the canopy assembly from the plane. To do this remove the bottom row of screws on the canopy. There are 2 shims at the aft edge held on by the last 2 screws on each side, be sure to keep them for re-installation.

After all the bottom row of screws is out, the canopy can be lifted straight up and off of the plane. This ought to be done by at least 2 people, and 3 would offer an additional level of safety. With a helper on the opposite wing root, lift the canopy straight up, taking care not to scratch the quarter windows with the sharp corners at the aft edge of the canopy. Once the canopy is above the turtledeck height, carefully hand it over to one person on the wing root. The other person then gets off the wing and comes to the trailing edge of the wing so that the person holding the canopy can hand it down. The canopy should be placed upside down on a padded surface. A packing blanket or sleeping bag folded a few times is a good pad on the ground.

=== Taking the interior plastic trim out ===

The windows are clamped to the frame at the "bottom" by another row of screws that hold the bottom of the window frame in place. Remove the screws and the stiffener can be removed. The interior plastic is sandwiched between the stiffener and the outside canopy. The interior plastic can now be removed. There are screws and rivets along the front edge of the plastic under the canopy bow seal. Remove the seal. Its probably old and in need of replacement anyway. A stiff bladed putty knife can help shear the glue that holds the seal in place. Use [http://products3.3m.com/catalog/us/en001/auto_marine_aero/aerospace/node_GSSPN37QHGgs/root_GST1T4S9TCgv/vroot_GSNNJ6NQDKge/bgel_GSK7J6PZ1Jbl/gvel_GSYCNP8Q3Ggl/theme_us_aerospace_3_0/command_AbcPageHandler/output_html 3M General Purpose Adhesive Cleaner] to soften the glue and remove it from the bow. Under the glue the pull rivet heads and the screws can be found.

Remove the screws and carefully drill out the rivets. Best practice is to use a small punch to tap the rivet stem back out of the way and then drill the rivet using the mandrel hole as a pilot. Use a 1/8th inch drill bit to avoid drilling the holes over-size. You will notice that the rivet holes here are countersunk in the front. Avex 1604-0412 blind rivets fit the bill here nicely when you go to re-assemble. (You can order them from your favorite supply house, they cost about a nickel each. Buy a dozen so you have extra for the future)

There are a series of rivets along the aft bow of the canopy as well. Remove them the same way as those of the front bow. These rivets are Avex 1601-0410, and once again, they are inexpensive, so buy a dozen.

With all the rivets and screws at the 2 bows out of the way, remove the #4 screws that hold the cover on the canopy latch and the center panel of the headliner in place. Remove the #6 screws above each window and the interior trim should now be free to come out.

=== Removing each window ===

The windows slide in the tracks, hence the need for the plastic to be warm. With the curvature of the canopy, the window must bend to slide out or in.

There is not much spare room to maneuver the window in the tracks, so the best plan is to "walk" it out about 1" at a time, alternating front and back. This takes 2 people to hold the canopy frame and move the plexi. Grasp the window by putting a flat palm on the inside and outside and pulling one end of the window out of the track slightly. When it moves, no matter how small the movement, position your hands on the opposite end of the window and repeat the pulling until it moves again. Keep swapping ends and walking the window out of the frame. After a few inches it may be easier to pull on the exposed edge of the window along the "top" of the plexi. Once it is completely out, the canopy shell is going to be very wobbly. Be careful not to damage the aluminum shell while the windows are out.

[[Image:Can_shell.jpg]]

=== Preparing the new window ===

Because of manufacturing tolerances, the bonded tracks can vary in distance apart, and its occasionally necessary to trim as much as 1/8" off one side of the window to let it fit the tracks. Measure carefully the length of the old windows and compare to the new ones. Sand or file the new one(s) if they are longer than the old ones.

Sand the edge of the new window completely smooth with sand paper in a succession of grits ending at no less than 400 grit. The goal is to remove the tool marks on the edge to leave a stress free surface. Be sure to wrap some sandpaper on a wood block and chamfer the sharp edges of the plexi with a small radius. Plexiglass expands and contracts much more than aluminum when subjected to "normal" temperatures on the ramp and in flight. This continual changing in size causes any discontinuity in the edge to become a stress concentration, and leads to small cracks and crazing in the corners, long before the window should need to be replaced. Examine the old windows on most light planes and you'll see those cracks forming in the corners. If you are using the Fletchair foam tape, it is best applied with some stretch to it, especially as you go around the corners of the plexiglas. This will make the tape "sit" down flat on the corners. This tape has a high "stickiness", and cannot be re-positioned, so apply it carefully.

=== Installing the new window ===

With the practice gained by walking the window(s) out of the tracks, you have learned the basic skill needed to re-install the windows. Lube each track and the felt or foam tape with a generous coating of clear silicone spray. Insert the window into the the track and line up both ends so that they start together. Now carefully walk the window into the tracks. The goal is NOT to wedge it tight on either end, but just take the movement that will easily happen, stop and swap ends to move the other end a little.

You can NOT force the plexi! Any suggestions of "putting a block of wood on the edge and hitting it" should be considered an admission that you didn't properly prepare the plexi, or that you are using the wrong technique. At the second Cody Convention in 2002, a group had been working to do a canopy window installation as a demonstration, and after much struggling by various persons that should have been able to install it, I was called upon to assist. After removing the jammed window from the frame and inspecting for damage to the foam tape, the plexi and the canopy shell, I re-lubed the window and the track and installed the window in a smooth easy motion alternately applying pressure at each end as I felt the resistance building and was later told that it took 41 seconds to install the window. I freely admit it usually takes 2-3 minutes to walk one into place, but I have NEVER found the need to resort to excessive pressure or hitting the plexi to drive it in.

Auxiliary Fuel Tank

2006-03-22T18:00:32Z

Mdrahzal:

There is an STC for an auxiliary fuel tank for Grumman 4-seaters. It is particularly useful for the AA5, which has a 37 gallon fuel capacity in the wing tanks. The STC holder is O&N Aircraft Modifications located at Factoryville, PA (9N3), http://www.onaircraft.com.

The auxiliary fuel tank is an 18 gallon tank that fits in the baggage compartment. It is about 1 1/2 to 2 feet high and covers about 3/4 of the floor space in the baggage compartment. The fuel tank feeds the right wing tank.
The fuel transfer must be started manually and can be stopped manually or will stop automatically when the auxiliary tank is pumped dry. (It will not stop automatically if the wing tank is full. Extra fuel will be vented overboard.) A fuel gauge for the auxiliary tank and the transfer switch are mounted just forward of the position of the cigarette lighter on the console between the pilot and copilot seats.

It takes approximately 80 minutes to pump the 18 gallon aux tank dry.

If you have installed this STC, you must carry a copy of the Form 337 with you in the plane. Otherwise you are liable to have the aux tank disassembled if, for example, a customs or law enforcement officer wants to search your plane and see if you are carrying drugs or other contraband.

----

[[Image:O&N_Tank_Side.jpg]]
View from Tiger Cargo Hatch

[[Image:O&N_Tank_Top.jpg]]
View from Front

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File:O&N Tank Top.jpg

2006-03-22T17:56:04Z

Mdrahzal: Top view of O&N Aircraft Auxiliary Tank installed in a Tiger

Top view of O&N Aircraft Auxiliary Tank installed in a Tiger

File:O&N Tank Side.jpg

2006-03-22T17:54:28Z

Mdrahzal: Side view of O&N Aircraft Auxiliary Fuel Tank installed in Tiger

Side view of O&N Aircraft Auxiliary Fuel Tank installed in Tiger