KADET SENIOR RC58 COVERING AND FINISHING

There is a variety of covering and finishing methods available that are well suited to the Kadet Senior. The final choice should be made after reading through each part of this section so that you can make an informed decision. Plastic iron-on coverings are popular because they are fast and easy to apply. Sig Koverall will give the model the strongest and most durable finish; while materials like silk, silkspan, and silray will appeal to the more traditional modeler

IMPORTANT! If you plan on using a finishing method that requires painting (Koverall, silk etc.) don't skip covering the fuselage and tail just because they are solid wood. Painting them without covering first is not enough. They will be much more resistant to splitting and breaking on hard impacts if covered, than painted.
Regardless of which covering you decide to use, it will not conceal a rough framework. Take the time to sand the model carefully with fine sandpaper (360-400 grit) before beginning to cover.

COVERING WITH SIG SUPERCOAT IRON-PLASTIC COVERING

Many modelers prefer to use an iron-on plastic covering on their models for several reasons. Some modelers simply don't like to paint or have workshops located where paint fumes can't be tolerated. Others like the speed and ease of application afforded by plastic coverings. You can generally finish a model much faster using an iron-on covering rather than a painted finish. However, plastic coverings are less durable and do not add nearly as much strength to the structure as fabric covering. On the plus side, plastic coverings are fairly easy to apply and result in a glossy, smooth finish. Plastic coverings tend to be susceptible to punctures and tears, but they are easily repaired.
If you decide to cover your model with this type of material, we recommend Sig Supercoat Iron-On Plastic Covering for it's low cost, light weight, and ease of application. To cover the Kadet, you will need at least four rolls of Supercoat. You can use one color for the wing and another for the fuselage, or go with all one color. Two pages of photo illustrated instructions are supplied with each roll of Supercoat, so only a quick outline will be presented here.


SURFACE PREPARATION

Like any other type of finish, Supercoat will not hide poor workmanship. The entire framework should be given a final sanding with 360 or 400 grit sandpaper before application of the material. Wipe the surface with tack rag or cloth dampened with alcohol to remove all excess dust.



COVERING THE WING

Cut a piece of material slightly oversize, remove the protective plastic backing sheet, and lay the adhesive side of the covering material against the structure. Tack the material in place around the edges using and iron to activate the adhesive. Seal the entire edge, then trim off the excess. Repeat this process for the top of the wing, being sure to overlap the material about 3/16" to 1/4". Always plan your covering sequence so that seams are on the bottom surface or at corners so they aren't so easy to see. Once both top and bottom have been covered, shrink the material with an iron or heat gun, heating evenly from one side to the other.

COVERING THE FUSELAGE

Cover the bottom, the two sides, then the top using separate pieces of material for each. When covering solid surfaces like the fuselage nose, better results may be obtained by starting at the center and working towards the outer edges. This allows the air to escape from under the covering as it is applied. Some modelers prefer to cover their tail surfaces before gluing them to the fuselage so that they are easier to handle. Be sure to cut away any covering where the surface attaches to the fuselage so that you have a strong wood to wood joint.


FINISHING TOUCHES

Once your model has been covered, you can add trim decorations using Sig SuperTrim Self Adhesive Trim Sheets. SuperTrim is made of the same material as Supercoat, but it has a sticky backing. Simply cut out your design and stick it in place. Thin strips can be cut from SuperTrim sheets or you can use one of the many brands of striping tape (such as Sig SuperStripe) which come in various colors and widths. Be certain to add some kind of stripe or decoration to the top of the wing so that while you are flying it is easy to distinguish the top of the airplane from the bottom.

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COVERING WITH SIG KOVERALL

Sig Koverall is relatively inexpensive, synthetic polyester-base, heat shrinkable fabric much like the covering used on full-scale aircraft. It is the strongest and most durable finish you can put on your Kadet - it will actually add strength and rigidity to the model's framework. If you are careful in cutting the material, one large sized package (KV-003, 48"x5yds.) is enough to cover all the parts of your Kadet. It can be applied to the model using dope or ironed on using Stix-It, a heat activated adhesive.

SURFACE PREPARATION

Whichever application method is used, you should first brush two coats of clear dope onto the framework wherever the covering material makes contact. Lightly sand after each coat to remove any raised grain or fuzz.

APPLYING KOVERALL WITH DOPE

Start with the bottom of the wing by cutting out a piece of material about 1/2" larger all around the panel, with the grain running spanwise. (The grain of Koverall runs parallel to the finished bias edge.) Lay the Koverall on the wing, pulling out any major wrinkles. Unlike silk, which uses water to shrink it tight, Koverall uses heat. In fact Koverall shrinks so well that there is no need to worry about such things as packaging folds or creases because they will come out easily with the iron. Brush clear dope around the edges. This will soak through the fabric and adhere it to the dope already dried into the framework. Allow dope to dry before trimming off the excess material with a sharp razor blade. Check for any rough edges or places that are not stuck down properly and apply more dope. Let dry.

APPLYING KOVERALL WITH STIX-IT

Directions for applying Koverall with Stix-It are on the can. The basic procedure is to apply Stix-It around the edges of the framework where you want the covering to attach. When dry, the fabric can be ironed-on around the edges where the Stix-It was applied.

SHRINKING AND SEALING KOVERALL

After both sides of the surface are covered (such as the top and bottom of the wing), shrink the Koverall evenly with an iron or hot air gun. (Be sure to read the Koverall package instructions.) The fabric can now be sealed with three or four coats of clear dope. Since Koverall has such a tight weave, fewer coats of dope are necessary to fill it than silk. Thin the dope until it brushes on easily and flows out smooth (about 25% to 30% thinner). The first coat should be applied sparingly to avoid puddles underneath the fabric. The second coat will seal most of the pores of the Koverall and from then on, running through will not be a problem. Sand the model VERY LIGHTLY with FINE sandpaper after the second coat is dry. The next two coats will completely seal and begin to fill the weave of the fabric. When dry, sand again. Your Kadet should now be ready for its colored paint scheme.

PAINTING

Color Dope should be thinned with Supercoat Thinner for brushing. This helps prevent brush marks and gives smoother coats. Flow on wet coats and avoid rebrushing back over an area already painted. If brush marks show, you need more thinner. For spraying, thin dope about 50-50. Add more thinner if the dope does not go on evenly.
If high humidity causes the dope to "blush" or turn white, the best way to handle this problem is to wait until the humidity situation improves and apply another coat of dope. This will eliminate the blush. If it is necessary to dope during high humidity, Sig Retarder may be used in place of part of the Supercoat Thinner (amount depends on the humidity) to reduce the tendency to blush.
Painting the entire model white is recommended for a good color base, particularly when white is part of the color scheme. Color coats can be sanded with 360 Tri-M-Lte or 400 or finer wet paper. When using masking tape for trimming, seal the edge with a coat of clear dope to prevent the color dope from bleeding under the edge. Don't leave the masking tape on any longer than necessary. The longer it is on, the harder it sticks.
Complete the job with several sprayed coats of clear over the color scheme. This seals the colors and adds gloss. For best results, it is not a good idea to try to mix different brands of paint. Use SIG products from the start.

COVERING WITH SILK, SILKSPAN, OR SILRAY

Although we refer to silk in the directions, all of these coverings are applied wet in the same manner as follows. Brush an unthinned or very lightly thinned coat of clear Sig Supercoat or Sig Lite-Coat Dope over all parts of the framework that will contact the covering. When dry, resand with fine sandpaper to remove any fuzz or raised grain. Brush on a second coat and sand again.

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The bottom of the wing is a good place to start covering. Cut a piece of material about 1/2" larger all around than half the wing, with the grain running lengthwise. (The grain of woven materials runs parallel to the finished bias edge.) Some builders next dip the piece in water and apply it to the wing.

We find that the silk sticks together and takes a lot of pulling and smoothing to get it in place so we do it a bit differently, as shown in the photo. Pin the dry covering in place and "paint" the water on with a brush.

Go around the edges, pulling out wrinkles and stretching the material smooth. You need not pull it up drum tight, in fact going to this extreme is not advisable. Just pull out all of the wrinkles. Use pins, if necessary, to hold the silk smooth, though wet silk usually stays in place without too much pinning. We like to fasten one end - in this case the upper center joint of the wing - pretty firmly with pins so that you can pull against this anchored end in stretching the silk the long way.
Brush around the outside edge of the stretched silk with clear dope. The dope will soak through the material and adhere to the dope already dried into the frame.


Trim off the edges with a sharp blade. I find a thin double-edged razor blade is ideal for this, but a single-edged blade does okay and you can't cut your fingers on it. On the bottom, trim off flush with the wing all the way around. Go over any rough area or places that have not stuck down properly with more dope and press the loose spots down as the dope is drying and getting stickier.

The top half is done in identical fashion except that the silk should be brought down over the edges instead of being trimmed flush. On the front, lap the silk over the edge of the bottom, over-lapping about 1/8". At the back, bring the material down over the back edge of the trailing edge but do not lap it over the bottom covering.

Use the same process on the tail section and fuselage.


Allow the water to dry out of the wood before applying the first full coat of clear dope. On the open framework area on the wing, brush the dope on sparingly. If too much is applied, the dope will be rubbed through the material and will run down the the surface on the inside and form a puddle. When these puddles dry, the large amounts of dope solids in them cause more shrinkage than the rest of the covering and a scarred area results. So apply dope very lightly the first time over. A second coat will seal most of the pores of the material and from this point, running through will not be a problem.

Use one or two coats of regular Supercoat clear on the wing to shrink the covering. After that, unless the covering is still not tight and unwrinkled, Sig Lite-Coat low shrink dope is recommended to help prevent warping.

A third coat of clear should provide a good base for color. Sand lightly when dry with 360 grit 3M Tri-M-Ite no-load paper. Don't bear down on the edges of the ribs or the silk fibers will be cut through. The color dope may be brushed or sprayed. Sig Supercoat Color Dope has low shrinkage qualities.

Apply the colored dope to the silk exactly as described in the "COVERING WITH SIG KOVERALL" section, starting with the white base coats.

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DECALS - Stik-Tite Pressure Sensitive

Cut out the decals with a pair of sharp scissors. Leave about 1/32" to 1/16" of clear edge around the decal. Round the corners as you are cutting. Wet the surface on which the decal will be placed with soapy water (use dishwasher detergent). Place the decal on the model and squeegee the water from underneath with a balsa paddle. Allow to dry. This procedure will prevent air from being trapped underneath as is possible when the decals are applied dry.

FINAL ASSEMBLY

94.

Hinge the rudder to the fin (3 hinges) and the elevator to the stabilizer (4 hinges). Follow the instructions below for installing Easy Hinges.

Installing Easy Hinges
Using a No. 11 X-Acto blade (or similar) cut a slot approximately 1/2" in depth and slightly wider than the hinge. After all slots have been cut. insert an Easy Hinge halfway into each slot in one of the pieces to be hinged. Then carefully slide the matching model part onto the other half of the hinges. You'll find it easiest to slide the part onto the hinges at an angle, one hinge at a time. At this point the surface to be hinged is attached but not glued. Align the two surfaces and adjust the gap between them as required. For best control response, the gap should generally be as small as possible but big enough to allow the control surface to move to the maximum deflection that you require. Place three or four drops of any brand cyanoacrylate adhesive (thinnest variety) directly onto the Easy Hinge in the gap. You will notice that the glue is quickly wicked into the slot as it penetrates both the wood and the hinges. Then turn the surfaces over and repeat the gluing process on the other side of each hinge. After the glue has cured, approximately three minutes, the joint can be flexed. You may notice a slight stiffness in the joint. This can be eliminated by flexing the surface to full deflection each direction a couple of dozen times. Don't worry about shortening the life of the hinge as they are almost indestructible.

95.

Install the control horns on the rudder and elevator as shown in the "Control Horn detail" on sheet 1 of the plans.

96.

Temporarily position the stabilizer on the fuselage. Refer to the General Alignment Diagram on page 20 of "The Basics of Radio Control" booklet to properly align the stabilizer. When satisfied, draw cut lines on the bottom of the stabilizer at the fuselage sides. Remove the stabilizer, then use a sharp knife to carefully remove the covering material at the leading edge and trailing edge where it contacts the fuselage structure. Now you can glue the stabilizer to the fuselage at the wood-to-wood joints using Kwik-Set epoxy. Recheck the alignment and adjust as necessary before the glue dries.

97.

Cut away the covering material on top of the stabilizer and fuselage where the fin makes contact. Glue the fin in place with Kwik-Set epoxy. Use a 90 deg. triangle to check the alignment with the stabilizer before it dries.

98.

Re-install the main landing gear wires with the nylon straps (see photo 69). Also re-install the nose gear bearing, the nose wheel steering arm, and the formed nose gear wire. Install wheels on all of the wires using a 5/32" wheel collar (not included) on each side of the wheel.

NOTE: the prototype model shown on the box lid used Williams Brothers Smooth Contour wheels with the enclosed hubs because they looked nice. Use of them requires cutting off the axles so they will be inside the hub. For best appearance and to prevent binding, solder a flat washer on the landing gear wire just past the axle bend.

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99. Install the clear plastic windshield using Wilhold RC-56 adhesive or thin CA. If you have painted your model, you can glue directly to the painted surface. If your model is covered with a plastic film, cut away a narrow strip of the material so that the windshield can be glued directly to wood. You can spruce up the appearance of the windshield/fuselage joint using 1/4" wide striping tape.

100.

The installation of your engine, fuel tank, and radio equipment is simply a matter of re-installing them as described earlier. If you haven't done so already, construct the balsa pushrods for the elevator and rudder as shown on the plans. Refer to "The Basics of Radio Control" and the instructions that came with your radio to complete the installation of your receiver, battery, switch and antenna.

PRE-FLIGHT CHECKOUT

Make certain that your model balances and has the correct amount of control movement. It is strongly recommended that you go through the Pre-Flight Checklist in Chapter 7 of "The Basics of Radio Control" before attempting to fly.

BALANCING

Read "Why Models Must Be Individually Balance" and "Balance is Part of the Trimming Process" boxes on the full-size plan.

The suggested balance point for the Kadet Senior is shown on the plan. Balance with an empty fuel tank but with all the other equipment installed and the model completely finished and painted. Suspend the model from the wing tips at the balance point. It should hang from the finger tips approximately level.

If the tail hangs down at the desired balance point, it is tail heavy. Add lead or weight to the nose or shift the radio equipment as necessary to get it to sit level. Do not attempt flight in a tail heavy condition.

If the nose hangs down below level, the model is nose heavy. If it is only a little nose heavy, don't do anything about it, it will be okay to go ahead and test fly. If it is more than a little nose heavy, correct by moving the radio batteries out of the nose and as far back in the cabin as is necessary to achieve balance. When slightly nose heavy, the model is more stable and less likely to stall or snap roll from over-elevating. It also cuts down reaction of the model to control movements and this is good during test and practice flights, to help prevent over-controlling. In the nose heavy positions you will probably need more elevator movement to get the nose up in low throttle and glide than in other C.G. positions, so make sure you have sufficient elevator travel.

Make any changes in the balance position gradually, checking results and the effect of the change on control responses and the performance of the model in the air.

CONTROL MOVEMENTS

Various brands of servos can give different control movement direction and amounts of travel. For this reason, follow the measurements given when setting the Kadet Senior up for flight rather than any particular horn hole drawn on the full-size plan. Shift the RC link to whatever horn hole will produce the amount of movement shown in the drawings. Measurements are made at the trailing edge of the control surface.



Control measurements are suggested as a beginning. Test flights may indicate a need for more or less movement, depending on individual model differences, center of gravity (C.G.), location etc.

It is not uncommon for the Kadet elevator neutral position to test out to be slightly drooped down from level. This introduces some nose down trim to keep the model from climbing when the transmitter stick is in the center. The exact best neutral elevator position for each particular model must be determined during flight testing. With the model flying at about 3/4 throttle, feed in down trim with the transmitter lever until the model flies level.

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Land and observe this position of the elevator. Adjust the elevator pushrod as required to keep this flight checked "neutral" position when the transmitter trim level is returned to the center.

FLYING

To Fly The Kadet Senior On A 4 Channel Radio

Plug the rudder servo in the fuselage into the receiver outlet marked aileron.Use of the aileron stick on your radio equipment to operate the rudder will enable you to develop the proper left and right reactions that will later be needed when advancing to aileron control, using the same hand. If you plugged the rudder into the rudder socket when only using 3-channels, you would have to make a difficult transition from one hand to the other at the time you advanced to aileron control, just about the same as starting over. The most important thing you are learning in the early stages is an automatic left and right reaction on a particular transmitter stick with a particular hand. Forget which control surface is doing the turning on a 3 channel, assume that the rudder is an aileron.


Be certain to carefully range check your radio equipment and see how it operates with the engine running before attempting test flights. A lot of problems can be avoided if the engine has been well broken-in and the idle adjustment perfected on a test block or in another airplane.

Takeoffs from grass fields are easily made if the grass is not too long or the ground too rough. Generally a lot of elevator application is required for liftoff. Be prepared to relax control pressure partially after becomming airborne so the climbout will not be too steep. On surfaced or smooth dirt runways less application of elevator will be needed.

If a good smooth take-off surface is not available, the model can be hand launched by the pilot's assistant. (Do not attempt to hand launch by yourself - instant action on the transmitter may be required.) Holding the front part of the fuselage with the left hand and under the tail with the right, run into the wind at a fast trot and thrust the model forward with the nose slightly up in a spear throwing motion. It is not necessary to achieve a lot of velocity in the launch - it is more important that it be released smoothly and with the wings level. The model may dip slightly and then should begin climbing at a slight angle. If it does not begin to climb after about fifty feet of flight, apply a small amount of up elevator to lift the nose.


Use the rudder to keep the wings level and headed straight into the wind until about 75 feet of altitude is obtained. Keep first turns gentle and not steeply banked. Stay up wind of the transmitter. Use trim levers on your radio equipment where necessary to obtain straight and level flight with the control sticks in neutral position but don't attemp to make these adjustments until the model is at a good altitude.

Throttle back at altitude to find out the model characteristics in a gliding condition so that some indication is seen of what to expect during the landing approach. It is a good idea to make several practice landing approaches at a good altitude to get the feel of the model for this approaching critical maneuver.

Make your final and complete landing approach while your engine still has plenty of fuel remaining so that the engine is not liable to stop before completion of the flight. This will allow application of power if the approach is being under shot. Notice the percentage of missed landings at an R/C field. Those undershot greatly outnumber those missed by overshooting. So if an approach that looks a little high is maintained, chances are good that a spot-on landing can be made.

After you get through the first flights, you should begin to "trim" the model's control surfaces. If it is turning to the right, for example, with the stick in neutral, and you must move the transmitter trim lever to the left to make the model fly straight, then land the model and position the rudder to the left of center by turning the RC link on the pushrod one or two turns on its threads. Check in the air for the result. Repeat the process, if necessary, until the trim lever is centered when the model is flying straight with the stick in neutral. You may find that the reaction of the model is different to high power and low power, requiring changes in trim lever position during flight, as for a landing approach. This is one of the controls you must learn to operate during practice flying, but it is not a critical matter at first since these minor corrections can be made with stick movement alone as you are steering the model along its course.

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RUBBER BANDS ON WING

Remember that different brands of rubber bands have different stretch characteristics. Apply some common sense judgement to the number of rubber bands used. It is a good idea to stretch each new band to its limit before using to locate any hidden defects. In case of doubt as to whether or not the wing is on securely, add extra rubber bands. Loading a wing in flight is more destructive than failure of the wing to come off in a hard landing. We looped two no.64 bands together to form a longer band and then used 10 of these looped-together units to hold the wing on, 5 crisscrossed each way.
Glue a piece of scrap plywood or plastic on the trailing edge at the point the wing rubber bands go over the edge to keep them from cutting into the wing. This should be done after covering.

DON'T WALLOW AROUND THE SKY!

A common mistake made by beginners is to fly around with the model having too much up trim. It climbs out steeply under full power in this condition (and is probably a safety factor for a rank beginner) and you can level it off by throttling back on the motor. However, in this over-up condition it wallows around with the nose high, it is hard to turn properly, and it will not fly into the wind because of low airspeed. The solution is to apply some down trim to the elevator to bring the nose down and make the model fly more nearly level at cruising power. It may be necessary to drop the elevator a bit from level by screwing in the RC link on the elevator pushrod to get enough down. The way to learn to do this trimming process is to experiment with the model in the air and note it's reaction to increased down trim or other changes. Moving the center of gravity in combination with trim changes can also alter the flying characteristics. For example, you may find that the balance point specified for test flights will be okay for the first few flights but when the model is trimmed down to fly more level under cruising power you may find that moving the balance point will give you better performance.

It is impossible to give exact directions for every case, since individually built models vary slightly and the engine used also affects results. But if the model is not flying in a satisfactory manner, then chances are it is not trimmed properly and should be adjusted accordingly. Do a little tinkering, a bit at a time. This is an instructive way to fathom the mysteries of perfect trim and in the process you can improve your flying.

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EASING THE TRANSITION FROM 3 TO 4 CHANNEL FLYING

In the first paragraph of the Flying section of the Kadet instructions, we tell you to fly the model by connecting the rudder servo to the transmitter stick normally used for ailerons so that when you move on to a 4 channel model after learning to fly there will be no hand switching required other than the change for nose wheel stearing on the ground. If you have a 4 or more channel radio to put in the Kadet, transition to aileron control can practically be eliminated by hooking the nose wheel to a 4th servo instead of the Kadet's rudder servo. Then the transmitter rudder stick can be used for ground steering and the aileron stick for in-the-air turning as you will be doing on 4-channel aircraft.

FLYING HINT

If, when using large size engines, you have difficulty getting this light wing loading model to land with the throttle in low, try using a 1" diameter prop and/or a lower pitch.





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SIG Mfg. Co., Inc............Montezuma, Iowa 50171-0520

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