Phoenix Model Flying Club (Dorset)

Hints & Tips

A small collection of articles that have been 'stolen' from our members.  OK, they may not all be 100% original, but we hope you find them useful.

Aerial Toggles Split Elevators Foaming Fuel
Side Winders Canopies Foam Wings
Servo Grommets 12V covering Iron Decals
LE Repair Wing Tapes Dust Extractor

Aerial Toggles On The Cheap

If you want to anchor the end of an externally mounted receiver aerial by tying it to the fin (or other bit of the back end) with an elastic band tensioner, this little idea should come in handy. When you cut off unwanted arms from your servos, keep all the bits that still have three holes. Clean up the cut end, and cut an angled slot into one end hole to form a hook.

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Thread the aerial through the remaining two holes as shown, and pull tight. It will not slip out even when soaked in fuel!

Split Elevator Pushrod Installation

Having trouble getting a Y-pushrod down the fuselage and out of the slots? Take two long small-sized snake outers and thread them though the push-rod exits. Push them down the fuselage until they are visible at the wing opening. Poke the two pushrod ends into the snakes, and then push the whole lot back down the fuselage. The snake outers will guide the pushrod ends past any formers or other obstructions and compress the ends together as you reach the narrow tail-end, until they exit cleanly out of the slots.

Foaming Fuel

Fed up with trying to stop that fuel foaming? Cannot insulate your tank due to the model design? Tired of trying to tune an engine that continually sucks up bubbles no matter how much you twiddle the needles? Trashed a model because it died in the air just after take-off? If so, try adding a drop or two of 'Armourall' car silicone dashboard cleaner to your new gallon can of fuel and no more foaming! Works a treat with no obvious side effects apart from a shiny fuselage!

Side Mounted Engines (Specifically an Irvine 61)

One member had problems where his Irvine 61 would cut out during an outside loop, regardless of the settings of the needle. He contacted Irvine, who seemed to have met this fault before and offered the following explanation:-

With the side-winding mounting used, oil collects in the silencer in all positive-G manoeuvres. When going vertically downwards in the first part of the bunt, this oil runs to the front of the silencer, and as the model goes inverted this oil runs into the engine and swamps the plug, causing the engine to cut. Their suggestion was to drill a small hole in the front of the silencer to drain it out, but a more satisfactory result was obtained by substituting a compact tuned pipe (Weston "Genesis") which not only completely cured the problem, but improved the power and quietened the engine as well.

Canopy Fixing (For the sports flyer)

Have you had problems fixing the canopy on your latest model? Cyno works OK, but fogs the inside and leaves it looking unsightly, while epoxying in place is probably best left to the purists. Having tried almost everything on the market, I have settled for the ordinary clear household glues such as Bostik All-Purpose Clearor UHU.(These look and smell a bit like the old fashioned Balsa Wood Cement). Position the canopy carefully, and then tape one edge to form a hinge. When satisfied, fold the canopy back and quickly run the glue all round the edge, taking care not to get strings of glue where you don't want them. Then hinge the canopy back into position, using more tape to hold it firmly in place. Leave it to dry for a few hours, and remove the tapes. Any gaps round the edge, such as at the front or rear, may be sealed with a generous fillet of the same glue. These glues dry quite hard, are gap filling and fuel proof (at least to normal Glo fuel), and hold the normal plastic canopies very well even when fixed directly to film covering.

Trimming TE/LE of foam veneered wings

Worry about sanding through the veneer when trimming the edging strips of foam wings? Borrow an old tip from the cabinet makers, and obtain the blade from a small to medium finishing plane. A blade about 1.5" (35mm) wide is ideal. This should have a very shallow cutting angle, 20degrees or less, the back must be absolutely flat, and the blade must be razor sharp.Use an ordinary modelling plane to rough shape the leading and trailing edges, leaving them about 0.5mm or less proud of the veneer surface. Then, laying your sharp plane blade flat on the veneer surface, and at an angle of about 45 degrees to the edge, work your way along to remove a fine curl of wood from the edges using the minimum of pressure.(Press too hard and you may cut into the veneer).

 

Several passes may be needed, but when finished the edge joint will be absolutely flush. With a little practice, perfect results will be obtained every time, and you will have no more fear of sanding through the veneer and weakening it.

Putting those little brass bits in micro servo grommets

Have you ever spent a few frustrating hours attempting to push the brass bushes into the grommets of a micro-servo? The hole often seems too small for the bush, and there is a real danger of the bush acting as a punch and making holes each side of the proper one. Try feeding a servo fixing screw through the hole from the other side first, and slipping the grommet over the screw. As you push the bush down, the screw centres the bush which then slides neatly into the hole. A little dab of soap/washing up liquid on the bush helps too.

Field Covering Iron - 240 - 12V Conversion

Has your old faithful covering iron burnt out? Don't throw it away, convert it into a 12V field-use iron, and you'll find that you'll wonder how you ever did without!

Carefully dismantle the iron, taking care to retain all the mica bits and the insulation from the internal wiring. Also note which bit and which wire went where - a sketch made before the thing drops apart would be useful! Take this opportunity to clean the contacts of the thermostat, but don't disturb its settings. Very carefully strip the old windings from the mica former, and discard them.

Now you will need some thick Nichrome wire to wind your low voltage element. The wire sold for cutting foam wings is ideal. If you can check the resistance of the wire, you want stuff giving about 2.5 ohms per foot (7.5 ohms per metre).

Your new element wants to come out at about 1.5 ohms, which will give about 8A current drain from the 12V battery, or nearly 100W of heating. As you'll get about 18" (45 cms) of wire on the new element, you'll need to double-wind it to get a suitable resistance. Straighten the wire by putting one end in a vice, and pulling the other end firmly with a pair of pliers. fold the wire into two at the midpoint, and lay the two strands side by side. DO NOT TWIST THEM TOGETHER, the winding will be too lumpy and you won't be able to get it back in the iron properly!

Make a neat hole in the mica former at each end, and thread the doubled-over end of the wire through one to project about 3/8"(1 cm). Now very carefully wind the two strands side by side, spacing them from the previous pair by about 1/16-1/8" (1.5-3mm). You will have to squash the bends down gently with a pair of pliers to get the winding to lay flat- don't overdo it or the mica former will break up. You should be able to get about 12-14 turns fairly evenly spaced before you get to the other end. Feed the remaining wire through the hole, and trim off any surplus to leave about 3/8" (1 cm) free. The element should now look a bit like this:-

Note - it is more important that each pair of wires don't short to the adjacent pair than it is to get the winding dead even, but do your best not to bunch them all up to one end. If you have access to a multimeter, check that the resistance is somewhere between 1.25 ohms and 2 ohms.

You will need to replace the original thin wires connecting the element to the thermostat and the mains cable, as quite high currents are now to be carried by them. Use thick copper wire, or several strands of thinner wire, for these. Join them to the element wires by using cut-down electrical terminals from one of those "Chocolate Block" connectors. :-

(The wires may be soldered to the "mains" cable, but you won't get solder to take to the Nichrome wire - don't try). Use the original sleeving over the bare wires. Any new sleeving you put in the hot end must be capable of withstanding the temperatures or else it won't work. Providing the connecting wires are stiff enough to support them, the screw terminals are best left bare, bending the wires to keep them away from any metal parts of the iron. The joints to the old mains cable should be sleeved, too. There is no need to "Earth" anything, so you can cut the old earth wire off the mains cable. For those who have lost their wiring sketch, the connections should look like this (the element may be the other way round in your iron, but the principle is the same):-

Now carefully reassemble the iron, taking care that neither of the screw terminals touch the outer case or any other metal bits. You may find that as the new element is somewhat thicker than the old one the case will not close fully without jamming the thermostat. Judicious use of washers between the cover and the sole will cure this - it doesn't matter if there is a slight gap all round at the joint - there's no high voltages around to jump out at you in this iron, but it is important that the thermostat still works. You can check this is OK by twiddling the knob, and somewhere at the cold end you should here the "click" or "ping" as it cuts in or out.

If you have access to a multimeter, check that neither wire of the "mains" cable is shorted to the case, or to each other, and that the connection to the element is made and broken as you adjust the thermostat. It may be safest to connect your iron to the 12V battery via a 10-15A fuse for starters, just in case, but all should be OK if the above checks are satisfactory. It is unlikely that your new toy will heat up as quickly as the mains version, as you are probably only putting about 50-70% of the original power into it, but give it time, and it'll get there. My original only has about 65W power, but as long as I keep it out of the wind it will get hot enough to re-shrink Profilm. Just the job for those bits that seem to flap about after a lot of usage, to get rid of those sun-raised wrinkles, or to repair damaged covering.

Home Made Decals

Here are a few ways of making your own colour decals if you have access to a colour printer.and a drawing package on your computer. The first step for any method is to get your image, either one you have drawn yourself, a "clip-art" image that takes your fancy, or a photograph you have scanned in.

Method 1

For the first method just print your image out to the size you want onto a THIN paper - 60mg or there abouts. Don't use too thick a paper, or it will take charge and wrinkle up later. Coat the back of the print with a generous layer of "Balsaloc" heat sensitive adhesive and allow it to dry thoroughly. Cut the decal out carefully with a sharp knife or scissors. Don't worry if it is a bit wrinkled at this stage. Depending on the colours in the decal and the surface you are applying it to, you may now have to iron this decal to the shiny side of a sheet of white Profilm/Oracover (leave the film on its backing, and don't use too hot an iron at this stage), as at the final stage the paper will get a bit transparent and the under colour may show through - you'll have to judge the need for this for yourself. If you use this backing method, cut the film to the decal outline after you've ironed the decal to it.

Now with a fairly hot iron apply the decal or decal/ film sandwich to the model, and at this stage the wrinkles should all disappear. If you are applying the decal to Solarfilm you should paint the area to be covered with "Primol" to ensure good adhesion, but this is not usually necessary for Profilm or Solartex coverings.

When the decal is in place, fuel and water-proof it with several coats of fuel proofer, taking special care to seal the cut edges. It is at this stage you will find the paper can get a bit transparent, and the base colour show through.

Method 2

Epson "Photo Quality Self Adhesive Sheets" are available, intended for making labels and signs. This is ideal for making small decals (I've only seen it in A4 size sheets), but is a bit expensive (about £1 per sheet). This is printed with your decal, separated from the backing sheet, applied to the surface, and fuel-proofed as above. One tip here is that when you have cut your decal out it is very hard to separate it from the backing sheet - if you are not careful the paper layers separate and leave the adhesive layer still stuck to the backing sheet! At best you will probably damage the surface of the decal. I leave a "tag" about 1" square at a convenient part of the decal, and carefully separate the decal from the sheet for a short distance into the decal. This way, if there is any damage or if the layers separate as you start to peel the layers apart, you will be able to cut this bit off and try again before you get into the decal itself! Then I trim the decal to exact shape and let it fall back onto the backing sheet until I want to use it. You can then get the decal off the sheet by rolling the tag back and brushing the edge of the decal up with your finger.

Method 3

Basically the same as method 3, but using a self adhesive plastic film made for the job. Although I have not tried either source yet, an e-mail from Brian Dubock suggests that Overlander (the battery people) can supply clear and white vinyl film, and that he has also had success with a thin, clear self adhesive vinyl sheet, sold as book covering by Woolworths. Thank you for that hint, Brian. Even when using these films it will be necessary to water-proof the finished decals, using your favourite fuel-proofer, as otherwise the ink will wash off in the rain!

Repair job to sheeted leading edges. A handy tool to help you.

Having to repair a nasty gash in the leading edge of a tapered glider wing, where not only was a slice of top and bottom sheeting missing but also the front parts of two ribs, the problem was to replace the broken ribs with properly shaped replacements: due to the taper, their shape could not be taken from the root rib. To help this along a simple scribing tool was concocted to help mark out the new ribs. The diagram below shows this, and the principle of use:-

The body of the tool must be long enough to bridge the gap, and the bottom edge must be smooth and straight. Set the pointer to the underside of the original sheeting and clamp tightly in place. Tack or wedge the roughly shaped replacement rib into place. Scribe the shape of the rib onto the face, keeping the line of the body following the "flow" of the taper. Remove the rib, cut to the scribed lines, and glue into place.

Fraying Wing Joining Tapes

Do you find that, however carefully you handle the glass fibre wing joining tape, every time you touch the stuff a bit more unravels itself? Not only is this annoying, but the unravelled bits tend to wander all over the place as you apply the epoxy. More unravels as you try to lift the gooey stuff off the joint, until its a wonder there is enouugh to finish the job. Try this idea. As soon as you get the tape out of the bag, apply masking tape to both ends, taping up both sides, and cut the frayed bits off through the masking tape. This will stop the stuff unravelling while you handle it. Leave the ends taped until the epoxy has started to gell, when it will be held together enough for you to trim it back without more unravelling!

If you are cutting the length you want from a longer stock piece, tape across the point where you want to cut it and cut through the middle of the masking tape leaving half holding each of the two cut ends. This way the ends of the stock will be safe until you need it again.

Dust Extractor

Try this inovative dust extraction system by Mike Cowley who was faced with sanding balsa outside because of the mess it created. Even when model making in the garage the dust found its way into the house.

Dust box

Having spotted an article in an American Publication for a 'Sanding Box' Mike set about building his own. With an old vacuum cleaner and some pegboard costing just £2.50 this is what it looks like.

 

Dust box

Here is a closer look. Turn on the vacuum cleaner, start sanding and watch the dust just dissapear.

Think about all those happy wives and partners!

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