|Cut Brass Tubing||Bend Brass Tubing||Extend the Life of Rubber Bands|
|Apply Decals||Rethread Servo Wire in Covered Wing||Revive a Dead Receiver Battery|
|How to Reinstall Fuel Tubing||Secure Wheel Collets||Make Perfect Film Cut Outs|
|Q-Tip Fuel Tube Joiner||Quick and Dirty Centre of Gravity||Avoid Stripping the Glow Plug Thread|
|Harden Up Your Horns||Winter Engine Starting||Problems with Twins|
|Tint a Canopy||Get an Engine Apart||Make Custom See-Through Decals|
|Cut SIG Koverall||Winter Mitt Safety Tip|
HOW TO CUT BRASS TUBING
Take a sharp blade, such as a #11 hobby knife, and press down on the tubing while rolling it to ensure a perfect circle. Only use light pressure to prevent the tubing from collapsing. Keep rolling the tube until the cut is complete. Make sure to take off any burrs as these will cut fuel lines. Just run the tip of the hobby knife around the inside of the cut tube and lightly sandpaper the outside of the cut. Wash off the cut to remove any very fine particles that could clog a carburetor.
HOW TO CUT BRASS TUBING
You need to bend a brass tube, but it kinks and cuts off the passage. Is that your problem? The solution for most airplane fuel applications is to insert the braided wire element of a typical nyrod set. To make it easier to withdraw, coat the braided wire with oil. Once the nyrod is seated inside the tubing, slowly ease the tube around the outside of a piece of wood, PVC pipe etc that has the curve that you wish to approximate. You can go up to 90 degrees. Once the bend is complete, withdraw the nyrod braided wire. Make sure you wash excess oil out of the tube.
HOW TO EXTEND THE LIFE OF RUBBER BANDS
Trainers typically use #64 rubber bands to hold on the wings. Unfortunately, a combination of ultraviolet light and glow fuel oil cause the rubber to deteriorate. There is not much we can do about the ultraviolet light, but we can slow down the effects of the glow fuel.
When you are finished flying for the day, one way or another, drop the rubber bands into a jar of water with a bit of dishwashing soap in it. When you get home, wash of the bands under the tap and let them dry in the sink. When they are dry, drop them into a jar with a bit of corn starch in the container. Put on the lid and shake the container vigorously. The corn starch will adhere to the bands and soak up any residual fuel. The small peanut butter plastic containers are ideal.
While this will prolong the life of the rubber bands, always inspect them when you are mounting the wing on the fuselage. You should never try to save 20 cents worth of rubber band only to see your wing leave the aircraft and cost you a lot more as your lawn dart buries its engine in the mud. It has happened in our club!
HOW TO APPLY DECALS
You have done a beautiful job building and covering your model - now comes the crowning touch as you apply the decals. The decal touches the film, it is crooked, you twist it and suddenly you have a misaligned and crinkled disaster. How do the pros do it?
Simple. Put a tiny drop of dish washing soap in a saucer of milk. Cut out the decal so that ROUNDED corners are achieved. Curved corners are better than sharp points in that the glow fuel will lift pointed areas quite quickly.
Dip your finger in the soap solution and was off the target area on the covering. make sure there are no particles of dirt on the covering.
Separate the decal from the backing carefully so that you do not get finger prints on the sticky stuff. Capture the decal with the point of a #11 hobby knife and float the decal into the soap solution. Pick up the decal with the hobby knife point and place the dripping decal on the wet area of covering. Quickly slide the decal into alignment. Working from the centre of the decal, use you finger tips to squeegee the water out from underneath. You want no bubbles. Let the decal dry for about 24 hours.
Note, some people like to use Windex instead of the soapy solution.
HOW TO RETHREAD A SERVO WIRE INSIDE A COVERED WING
You have had a problem - your servo lead inside the covered wing has come unplugged, or was damaged in a crash. Somehow you have to get the lead threaded from the centre of the wing to the outboard servo.
First, you have this problem because you did not insert servo wire conduits inside your wing when you were building the wing. That is, you did not take a long piece of newspaper soaked in diluted carpenter's glue and wrapped a couple of times around a half inch dowel. You did not pull this soaked tube off the dowel and let it dry in the upright position. Equally, you did not tack the conduit in place along the run between the ribs from the centre to the outboard servo.
Does this sum it up? If there is a least a hole in each rib down the length then, don't despair! If you only made a tiny cut and glued in the wire, then despair!
For those who made generous holes in each rib, the answer is to go to the hardware store and buy a length of the articulated chain used for sink stoppers.
Put a small weight on the end of the chain, drop the chain into the servo bay or the wing centre hole. Holding the covered wing in the vertical, wiggle the articulated chain back and forth until it fall through the hole in each successive rib.
Once the chain appears at the other end, tie the servo wire to the chain and pull the wire through.
HOW TO REVIVE A DEAD RECEIVER BATTERY
So, you had a great time at the field! When you got home you regaled your spouse with the minute details of your flying prowess. Unfortunately, you forgot to turn off the receiver in your plane.
When you put your plane on the charger to top it up, it looked like it was doing something - but nothing, zip, da nada! What's the problem?
The typical nicad battery in a receiver pack can only drop to 1.1 volts before it goes into the "dead" zone. The charger can see it anymore and it will not charge. Now you have two options. One, go to the hobby store, admit your error and buy a new pack. Two, try this trick.
Plug the leads from your battery tester - you have one of course - into the charging lead of your receiver battery. Take the banana plugs on the other end and touch them ever so quickly to your 12 volt field battery. We are talking about a micro burst - you aren't trying to weld anything. If you hold the leads to the 12 volt battery too long, you WILL be going to the hobby shop!
Plug the banana leads back into your battery tester. If the micro burst worked you will see a much higher level. One that will now allow the battery charger "see" the pack and start charging. If you see only a slight improvement, then repeat the foregoing and give the pack another micro burst. Test again!
Whatever you do, don't charge up and go out flying. This receiver pack is now suspect and must be proven.
To prove the pack, put it on the discharger and let it drop down to a nominal 4.4 volts (1.1 volts per cell), where your automatic charger will then start recharging it. The discharge readout will tell you how well this pack now performs.
Caveat: Do this at your own risk.
HOW TO REINSTALL FUEL TUBING
So, you have finally figured out that the reason the engine won't run is that you have a leak in the fuel tubing, either on the fuel intake or the exhaust pressure run to the fuel tank. You can get the tube out, but how are you going to get it back in without taking the airplane apart? You already know what the problem is, trying to push bendy fuel tubing through the firewall is a lot like trying to push rope uphill!
If you are lucky, you will be to get at the hole in the firewall from the front of the aircraft or the wing saddle. The trick revolves around using a length of strong, but flexible piping that has the same inner diameter as fuel tubing. Usually the plastic tubing sold as a conduit for the antenna wire is just right.
Start the antenna tube in from the front or the middle until you have guided it through the firewall hole and you have a length showing at both the front and the middle. Now take a generous length of the replacement fuel tube and slip into the antenna tube. Make sure the antenna tube is about half an inch into the fuel tube. Now put a drop of thin CA on the join and let it wick into the join.
Now take a sharp razor and carefully whittle down the front of the fuel tubing at the join. The aim is to make a cone shape so that it will thread through the firewall easier than if the front of the join was full size. Now lubricate the outside of the join with a dab of vaseline - this is to aid its passage through the firewall.
Carefully pull the antenna tube and drag the fuel tubing through the firewall.
Cut off the join between the fuel tubing and the antenna conduit.
HOW TO SECURE WHEEL COLLETS
It is a little know industry secret that wheel collets are especially designed to come off just as you are taking off. Since the wheel inevitably comes off when the collet departs, this results in either a nasty cartwheel if still on the ground, or a perplexing problem as to how to land if the wheel came off in the air. The collets come off because of engine vibration.
There are three tricks that will defeat the greedy collet industry. First, some grinding and second and third some gluing.
At the end of the axle, grind a flat spot about one quarter of an inch starting at the end of the axle. Normally it is a good idea to put the flat spot on the top if you like the wheels on the ground, or the bottom if you work on your plane with the undercarriage pointing at the clouds.
Before you put the grub screw into the collet, put a dab of Loctite on the grub screw and in the thread cavity. Loctite is used in industry to stop nuts and bolts from vibrating apart. You can find Loctite, or a derivative, in Canadian Tire. Just make sure you buy the type that will allow you to take the grub screw out in the future.
Now when you tighten that cursed grub screw, it will go in further than the axle diameter and have something to grab onto.
Finally, just to make sure, put a dab of clear bathtub sealant on the end of the collet so that it covers the grub screw and the axle end. The little rubber cap will hold things together, but can be torn off if required.
Note: Don't use axle collets on smaller tail wheels. Simply solder a washer to the axle on both sides of the wheel.
HOW TO MAKE PERFECT FILM CUTOUTS
You have finished covering your plane with film and now you have to take a sharp pointed razor knife and cut-out the slots for your plastic push rod exit hoods.
The slot in the balsa or light ply is easy to find and you just wonder how steady your hand is going to be and whether the film is properly sealed.
As demonstrated by Peter Woo, the trick is to lightly seal the perimeter of the slot with your iron. Then, take a one foot length of music wire and wrap some tape around one end to provide some insulation. Then heat the bare end and with a torch. Once the rod is hot, plunge it through the film in the centre of the slot and work it to the outside and all around the slot. The film will melt and follow the contour of the slot.
The result is neat and very clean.
HOW TO USE A Q-TIP TO JOIN TWO PIECES OF FUEL TUBING
The title say sit all. In case you missed it, the long version follows.
You are at the field and you have to join two pieces of fuel tubing. You have no brass tube and everybody else is equally dry. But, you do have a Q-Tip in your flight box - doesn't everybody clean their ears on the flight line?
Simply cut out a one inch length from the centre of the plastic Q-Tip shaft. It is the exact size required.
HOW TO AVOID STRIPPING THE GLOW PLUG THREAD
Your darned engine won't start and you have finally concluded that you have to pull the plug - glow that is. You take your handy dandy wrench and unscrew it. You check out the plug and there is nothing wrong - yet. You put the plug in the wrench, carefully cant the plug three degrees off vertical and torque her down. Now you have a problem - you just stripped the thread!
While the thread of the glow plug is as hard as steel (literally), the thread in the head of the glow engine is a lot softer. So, when you are tired, your fingers cold and you have forgotten your bifocals, it is very easy to misthread that plug. There is a neat, cheap solution.
Before you rethread that plug, take two inches of fuel tubing and insert the nipple of the plug into one end. Put the plug into the head thread and twist gently. If you are misaligned the nipple will just twist on the fuel line and no harm will be done. If the plug starts to go into the bore, then you can take out your wrench and finish the job.
HOW TO DO A QUICK AND DIRTY CHECK OF THE CENTRE OF GRAVITY
We all know that it is very important to make sure that the model has the correct centre of gravity. That is because the model flies in a near-perfect viscous solution and it will tilt in the direction of higher weight. Tail heavy is of course the worst condition.
The real quick and dirty is to look at the main wing, assuming a monoplane, find the highest point on the top of the airfoil and then pick the plane up by the wing tips at that highest point. A slight nose droop is desirable.
A slightly more accurate method can be performed in the privacy of your own home. It involves really scientific, sophisticated tools known only to the ancient Egyptians - string and a weight to create a plumb bob.
Take a piece of string and tie it around the nose - perhaps the prop shaft - or something that will not get damaged. Secure the other end of the string to the tail so that there is a loop about three times the length of the plane. Hang the loop on a hook that your have driven into the beautiful moulding of the dining room ceiling. Move the plane along the hook until it is approximately level with the dining room table top - the one with the scratches from the fallen plaster.
Now make a plumb bob out of a small weight and a length of string. Thread the plumb bob over the hook in the ceiling and let the weight come down slowly until it is just above the wing top. Tie it down at this length.
When the plumb bob stops swinging, the weight will be just over the centre of gravity. You can then compare this to the designer's centre of gravity. Add weights to the tail or nose until the plumb bob is over the correct centre of gravity.
It it wasn't for the cost of repairs to the dining room ceiling and the dining table, this would be a relatively cheap system.
HARDEN UP YOUR HORNS
Actually, the horns are plenty hard enough - just wanted to get your attention. The problem is that the hard horns - the ones that transmit the servo thrust to the control surfaces - sit on soft stuff. Over time the soft stuff starts to cave in and you get slop or structural failure. This is most common on balsa, but can also be a problem with light ply. Most plans for trainers do not mention this problem. It could be assumed that the manufacturers believe that no trainer will survive long enough for this problem to manifest itself.
There are two solutions. First, if dealing with a balsa surface, either put of spot of thin CA onto the wood directly where the hard horn will be bolted OR splice in a square of thin light ply on both sides of the load-bearing spot and put thin CA over the ply. If dealing with just light ply, then just do the second part of the first part.
This CA wicks into wood and turns it into a very hard surface.
HOW TO START YOUR ENGINE IN THE WINTER
The first thing to acknowledge is that everything is going against you when you try to fly in the winter.
First, glow fuel needs to vaporize in order to provide a gas that the glowing glow plug can ignite. At low temperatures, our fuel just is not warm enough to provide a good vapour source. If you have old fuel that has any water vapour in it, then you will really have a tough time - use only fresh fuel.
Second, we have a lubricant mixed into the fuel to provide lubrication to the engine's moving parts. With cold weather the lubricant congeals making it very hard to turn over the engine with a low torque starter. Castor oil lubricants tend to congeal much more than the synthetics.
Third, all your electricals are going to be working at less efficiency in cold weather. Therefore, your flight box, your glow starter etc all have to be charged to capacity to give you the best chance.
As an aside, flipping the engine over manually about 10 times will create some friction and start to loosen up the gubbins before you lay that heavy duty starter on things.
In order to overcome the first difficulty, many people use a squirt of lighter fuel in the carb to get that first pop. Once the engine turns over, it produces heat and then the glow fuel will vaporize enough to sustain activity. Other people use ether from various automobile starting spray bombs. The thing to remember is that a little goes a long way as neither the lighter fuel or the ether sprays have any lubricant mixed in.
Cold weather starting often requires "choking",
for both 2 and 4 strokes, to richen up the mixture. This is
very easily accomplished by putting your finger over the end of the muffler and cranking the motor with
an electric starter.
In winter, it is advisable to run 2 cycle engines with a "hot" glow plug. That is, a plug that is designed to have the platinum glow element react as strongly as possible with the glow fuel. An OS #8 or an Enya #3 are good but expensive choices.
Finally, in winter your engine will have to run a lot richer than the summer. The key difference is the amount of water vapour in the air. If your engine was running nicely on a hot, muggy day in July, you will have to richen (open) the needle valve by as much as 8 clicks to run on a dry, cold winter day.
HOW TO TINT A CANOPY
Ever wonder how those great looking tinted
canopies got that way? In many cases, the builder
dyed the canopy using dyes intended for tinting clothing! The process is actually quite easy, and
the dye itself is easily obtained and quite cheap. I've found that Ritt powdered dyes are quite
effective in tinting the plastic canopies found in most model kits, and are available in most
drugstores, priced around $2 per package. When using powdered dye to tint plastic canopies,
here are some tips to consider:
Make sure that
the canopy is squeaky clean before dyeing. Washing in mild dishwashing
detergent is effective here, and will avoid unsightly fingerprints in the final work. Dry using
a soft cloth (not paper tooling, which is almost always abrasive to some degree).
used for dyeing must be clean as well. Stainless steel or glass containers
are the best for this process. Use a container that is just large enough to allow the canopy
to be fully immersed in the dye bath.
appropriate for working with dye. It is also a good idea to place the
dyeing container within a stainless sink and to clear any items from the working area. If
you do splash some dye on a hard surface in your work area, some diluted bleach will
take the stain out (rinse the area thoroughly with water after using bleach!).
A meat thermometer
is perfect for measuring the working temperature of the dye
solution. Also, a pair of cheap wood or plastic tongs are handy for handling the canopy
while it's in the dye bath.
Fill the container
with hot water first, then pour in the dye (this will help avoid splashing
dye around). Mix thoroughly but avoid splashing. Remember to use only enough water
to fully immerse the canopy. The object is to create as strong a dye solution as possible
to speed up the tinting process.
the dye bath using the scraps of plastic remaining after trimming the canopy
from its "as shipped" form, principally to determine if the solution is too hot. I've found
that an optimal working temperature is 150-160 degrees F, but you should immerse a
scrap for a few minutes to determine if there is any chance of deformation at these
Place the canopy
upside down in the dye bath to avoid trapping air bubbles. To remove
any bubbles and to ensure consistent tinting, periodically shake the canopy gently within
the dye bath using the tongs. Avoid scuffing the sides of the container with the canopy.
remove the canopy and observe the level of tinting. Some plastics take
more readily than others, and the level of tinting you desire may vary, so you have to give
it an "eyeball" every few minutes.
If you desire
a really opaque level of tint, or if the plastic takes dye slowly, it may
necessary to reheat the dye bath. This is where a stainless steel container comes in
handy: remove the canopy, rinse it in tepid water, and set aside. Place the dye container
on the range and use LOW heat to gently bring it back up to working temperature,
checking with the thermometer. Don't overheat! Then remove from the range, and
reimburse the canopy.
Once the canopy
has reached the desired shade of tint, remove from the dye bath and
rinse thoroughly with tepid water, then dry using a soft cloth.
Voila! A professionally tinted canopy!
-- Dave Tatosian
HOW TO TAKE APART AN ENGINE
You have to take your engine apart, but find that the casing just won't budge. The answer?
Put it in the oven at 400 degrees for 30 minutes. Tap the casing lightly and the parts will fall out.
HOW TO MAKE CUSTOM SEE-THROUGH DECALS
It is quite easy to make decals by carefully cutting out the design from Monokote or Ultracote. However, these materials are not transparent and, when you cross colour lines, the effect is sometimes not desirable.
To make custom decals of any complexity, in black/white or colour you will need:
* a personal computer
* a scanner to capture the image
* image manipulation software to allow you to compose, size and finalize the graphic
* a laser or colour inkjet printer
* Avery 08665 Clear single sheet decal labels.
Avery 08665 Clear single label sheets come in packets of 25 and cost $30 Cdn. Not cheap. Therefore, it is highly recommended that you compose your graphic and test print it to ordinary paper before committing it to Avery. Since you can only pass the 8.5" x 11" label through the printer once, you should endeavour to lay out the graphics so that you will minimize the wastage. The labels can be found at Business Depot or The Office Place.
Once printed, either using a laser black/white or colour or an inkjet black/white colour output, the trick is to fix the printed image so that is fuel-proof. One way is to simply peel off an unprinted clear label and carefully lay it over the printed version - do this very carefully to eliminate any air bubbles. If required, a hobby knife with a fresh blade can then be used to cut out each individual decal.
Others have found that water-based polyurethane varnish can be used to paint right over a laser-printed graphic to make it fuel proof. As always, there is a bit of technique to learn. Because a laser printer was used, the printed side has to be carefully washed in a very dilute solution of dish washing soap and water to remove the toner residue or streaks will show when painted.
If an inkjet was used, water will possibly dissolve the graphic - spraying it with clear automobile paint will help IF done carefully. That is, the first pass must be only an extremely light burst, followed by equally light bursts as each layer dries. If done carefully, the colour ink will not bleed.
The Avery Clear decal has a sticky backing that will allow you to apply it to your plane using a highly diluted mix of dish washing soap and water to float the decal into position. If the decal crosses a colour line, you will he happy to see that the decal is transparent and no harsh discontinuities result.
WINTER MITT SAFETY TIP
If you use a mitt that covers the transmitter so that you can go without gloves, follow this safety tip. Loop a #64 rubber band around the left side of the transmitter carrying handle. Then loop another #64 band to extend the first one. Take the length of rubber down the back of the transmitter and bring it under the bottom and loop it over the left hand (throttle) stick so that the throttle is held firmly in the idle position. Flip the band off the throttle once you are safely inside the mitt. It is all too easy to accidentally hit that throttle stick into full throttle while you are struggling to get into the mitt - your colleagues will not like a runaway plane.
HOW TO CUT SIG KOVERALL
Basically, when you try to cut SIG Koverall with a pair of scissors, you get get a mess of chewed up fabric. The trick is to buy an OLFA rotary cutting blade and the attendent self-healing cutting board. They are pricey, but invaluable. Measure out the size of cloth required, and run the rotary cutting blade along a straight edge. Be sure to nip any threads that were not cut as the strings pull very easily.
HOW TO SOLVE PROBLEMS WITH TWINS
Nobody in the club has any idea how to solve the problem of twins. Graphics provided by Skip Pothier.