KADET SENIORITA RC60 COVERING AND FINISHING
The prototype Kadet Seniorita was covered with Sig Light Weight colored silk. The black decorations were painted with Sig Supercoat Dope and the pinstriped with Siver Supercoat. The colored silk saves weight because it needs only clear dope for finishing.
The majority of RC trainers are covered with plastic film because of the simplicity of application. There is no better iron-on covering than Sig Supercoat. Check the Sig Catalog for more information and a listing of the wide range of available colors.
The manufacturer's directions for applying iron-on coverings are packed with the material. Follow these closely, for different types of covering have different iron temperatures and techniques of application.
Whatever kind of covering you desire to use, it will not conceal a rough framework. Sand carefully with fine sandpaper before beginning.
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.
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 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 framework.|
Trim off the edges with a sharp blade. We 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. Sig Supercoat Color Dope is a low shrink base. A third coat of clear should provide a good base for color. Sand lightly when dry with 220 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.
Supercoat 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.
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.
Masking off curved parts for painting is made much easier if 1/8" wide masking tape is used. This will bend around corners easier than wider tape. Strips can be cut off of regular tape with a straight edge. After the decoration is outlined, wider tape can be joined onto the 1/8" tape to block off the nearby areas not to be painted. I use paper taped on to much of the rest of the model to shield for spray painting.
Another way the curved parts of the decorations and pinstripes can be applied is with the use of a mechanical drawing ruling pen to draw them on the model using paint in the pen instead of ink. Thin dope slightly with blush retarder to slow the drying process and aid the flow of dope through the pen points. Clean the pen frequently with dope thinner and wipe on a cloth before reloading with fresh dope. Don't try to draw a thick line with the dope and pen but instead draw a thin line on each side of the desired pin stripe (about 1/8" wide were used on the original) and fill in between the lines using the pen free hand and opened up for wider flow. If you have a steady hand, use a small brush. Use a French curve to outline curved parts of the decorations.
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.
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.
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 Seniorita 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.B. 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.
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 Seniorita 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. 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.
To Fly The Kadet Senioria 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.
Flying The Kadet Seniorita On Two Channels
3 channels are best, but the Kadet can be flown on 2 channels when this is necessary. We recommend use of rudder and elevator control for the two channels. Motors above .15cu. in. in size should be run throttled back to about 3/4 power by tying down the throttle arm at the desired speed.
Altitude gain on two channels is controlled by use of elevator down trim or application of down elevator stick movement when required. On first test flights with a 2-channel Kadet, fill tank 1/2 full. This will help keep the model from gaining too much altitude if the trim is not set properly at first and the rate of climb is excessive.
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.
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.
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.
|The position of the landing gear affects the performance of the model during takeoff and landing. A position that makes it easy to take the model off may not work well on landing. Conversely, if the model is easy to land it may be difficult to lift off. In designing a model we choose a location that we feel represents the best compromise between takeoff and landing characteristics. Sometimes an individual flier may find this position not quite suited to his personal preferences or skills. So we are explaining below some alterations that can change either the takeoff or landing characteristics if desired. To alter the standard level ground attitude, use different size wheels, bend the main gear or lock the nose gear in a different position, using the set screw on the nose gear steering arm or a wheel collar as previously described.|
Model in Level Ground Attitude|
This is the standard kit configuration as shown on the full size plan.
Model in Nose Down Ground Attitude|
Lands easily and stays on the ground with little or no bounce. Excess landing speed can more easily be tolerated with this configuration. Takeoff is more difficult. The model will run on the ground at high speed without lifting off because the wing is at a negative angle. Extra up elevator movement of the stick is required to lift the nose wheel off the ground and then the model may zoom up sharply as it lifts off. If the flier is prepared to relax the up elevator prompltly upon lift off, it can be managed OK. This nosedown ground attitude is good for fliers who can handle takeoffs competently but are unable to land in good shape. (The average beginner usually learns to takeoff sooner than he acquires landing skill.)
Model in Nose Up Ground Attitude|
Lifts off easily and smoothly in a scale-like manner with just a touch of up elevator. In the case of a Kadet, it may even takeoff by itself without pulling in up elevator with the stick. Landings are more difficult because the nose wheel can touch down before the main wheels, causing the model to rock backward onto the mains and/or bounce several times before sticking on the ground. If the landing speed is excessive, the first bounce may make the model become air-borne again. When using this ground attitude, the air speed on landing must be reduced, the model flared nose high and touchdown made on the nose wheel and main gear simultaneously or on the main gear first. This configuration requires better flying skills than does the kit configuration level attitude or the nose down attitude.
TAPPING ALUMINUM ENGINE MOUNTS
Clamp the engine mount securely in a vise and center punch the motor mounting holes. Drill the holes with a sharp twist drill bit in a variable speed electric drill. If possible, use a drill press instead of a hand held drill. Lubricate the drill bit with machinist's cutting oil, special aluminum tapping fluid, or other light household oil such as Marvel or 3-in-1.
|Run the drill at a moderate speed with moderate pressure. Let the bit cut its way through the aluminum at its own rate. Don't try to force it with excess pressure or high speed. Aluminum galls easily and may jam and break the bit if forced. If resistance builds up, back it out of the hole frequently and clean off the metal fragments. Relubricate the bit and hole with oil and continue drilling.|
|Tapping the drilled holes is easy if the same precautions are taken. Lubricate the tap liberally with cutting oil. Use moderate constant pressure when turning the tap into the hole. If resistance builds up, back the tap back out frequently and clean the fragments out of the threads. Use plenty of oil and work slowly.|
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SIG Mfg. Co., Inc............Montezuma, Iowa 50171-0520
|LIMIT OF LIABILITY:|
In use of our products, Sig Mfg. Co.'s only obligation shall be to replace such quantity of the product proven to be defective. User shall determine the suitability of the product for his or her intended use and shall assume all risk and liability in connection therewith.