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Friday, May 25, 2007

Too Lean or Rich for Nitro Engine?

Nitro or glow engines use nitro fuel but it's actually a mixture of fuel and air that goes into the engine. The right fuel/air mixture keeps the engine running at its best. The wrong mixture can cause overheating, excessive wear, or cause the engine to stall. This fuel/air mixing takes place in the carburetor.

Lean and rich refer to the mix of fuel and air. To lean out or richen a nitro RC engine means to adjust the mixture of fuel and air going into the engine. Lean is the addition of more air to the fuel/air mixture. Rich is the addition of more fuel to the fuel/air mixture.

Lean
When you lean out a nitro engine you are adjusting the mixture so that there is more air going into the nitro engine than there is fuel. This provides a little more horsepower but can result in very high engine temperatures. If you are not careful leaning out a nitro engine you could run it too lean. This will wear out the glow plug prematurely or cause engine failure.

Rich
When you richen the nitro engine's mixture you're adding more fuel than air to the nitro engine. This can give you better results for some kinds of races because this method, unlike leaning out, will give you cooler engine temperatures.

But if running too rich you can not only bog the engine down and stall out but also flood it and foul the glow plug.

When to Lean Out or Richen a Nitro RC
You might be running too lean if the engine dies while idling, you don't see a light stream of blue smoke from the exhaust, or the engine gets so hot that a drop of water on the engine immediately starts sizzling and popping.

Too much blue smoke or a lot of unburned fuel from the exhaust and an inability to reach top speed are some some signs that you may be running too rich.

How to Lean Out or Richen a Nitro RC
Engine tuning and adjusting the fuel/air mixture involves adjusting the high-end (high speed / engine temperature) and low-end (low speed / idle speed) needles on the carburetor. This is also called dialing in your engine. There are usually base-line settings for each nitro engine that provide a good starting point for adjusting the needle settings. You'll turn each needle in very small increments to lean out or richen the fuel.

Turn clockwise to lean out or add air and counterclockwise to richen or add fuel. The low-end needle controls idling and low speeds. The high-end needle controls how the engine accelerates and runs at high speed and has a greater effect on engine temperature.

Lean, Rich, and Engine Temperature
You want to adjust the fuel/air mixture so that your engine runs at an optimal temperature which is generally somewhere between 225-250 degrees Fahrenheit for most nitro engines. Much over 250 degrees could cause a lot of damage and also shortens the life of your nitro engine.

Check your nitro engine's temperature often to keep it at optimal temperature for longer runtimes and overall better life for your nitro engine. If the running temperature is less than 200 degrees you need to turn your high-end needle adjustment clockwise to lean out the mixture a bit to get the temperature up a little. If your temperature is above 250 degrees you would bring it down by adjusting the high-end needle to richen the mixture by rotating the high-end needle counter-clockwise. The ambient temperature outside and the elevation according to sea level will adversely effect the nitro engine's temperature so adjust accordingly.

Nitro Engine Break-In Procedure

Proper nitro engine break-in is critical for long-lasting performance of your RC. Every new nitro engine should undergo a break-in procedure. Breaking in a nitro engine takes anywhere from one to two hours and about 3-5 tanks of nitro fuel. If you do the nitro engine break-in properly, the up-keep on your RC vehicle is less costly than if the procedure is done hastily and incorrectly. Be patient.

For your nitro engine break-in, choose a clean, flat, paved or smooth surface. You'll be doing the initial break-in with the body off so you don't want to be kicking up dirt or doing flips during break-in. During the first couple of tanks of fuel focus on varying and limiting your speed. Don't run your engine past half-throttle. Don't run at a constant speed.

During break-in deposits build up and can foul out the glow plug so your engine might seem like it's stalling or not running properly. This is normal. Proper break-in alleviates these symptoms. Do have an extra glow plug or two handy in case you need them.

Operate Safely
Here are simple safety checks you need to do before starting:

1. Turn on the Controller First
Turn your transmitter/controller on first followed by the receiver on the RC. When finished running your RC, turn the receiver off first, then the controller. This sequence will keep your nitro RC from running amok if someone nearby is running on the same frequency. Do yourself a favor though and check frequency before running your RC.

2. Put The Engine in Neutral
Move the throttle forward and reverse to ensure your nitro engine is in neutral and is in the idle position when the throttle is released.

3. Check Your Steering
Move the steering controls from side to side. If steering seems sluggish or hesitant, replace the receiver's batteries before proceeding.

Prime Your Nitro Engine
Start up your RC. Watch to see if fuel is moving through the lines. If fuel doesn't reach the carburetor after 3-5 seconds place and release your finger over the tip of the exhaust for a couple of seconds to help the engine start. This is known as priming the engine. Be careful when doing so because if too much fuel goes into the engine when priming, it will flood causing the engine to lock up.

If the engine does flood use your glow plug wrench to remove the glow plug. Place a rag over the engine head. If equipped, use your electric starter. Start the engine to get the remaining fuel out and wipe off the head with a dry towel to remove any remaining fuel. Reinstall the glow plug and start on the first tank of the break-in process. Your nitro engine shoudn't be primed for more than 1-2 seconds at a time to avoid flooding.

Do Five Tank Nitro Engine Break-in
With each tank of fuel you'll increase the amount and duration of throttle. Use these tank-by-tank guidelines for your nitro engine break-in.

Tank 1
Give the engine one-quarter throttle slowly for 2 seconds. Apply the brakes. If you pull back on the throttle too fast you may cause your engine to stall.

When there is a nice trail of blue smoke coming from the exhaust it means your fuel mixture is properly set and the engine is being lubricated. If no smoke is present, richen the fuel mixture by giving the air/fuel mixture needle a quarter turn until smoke is present.

Continue running the first tank of fuel, repeatedly giving it one-quarter throttle then braking until it is almost empty. Do not run the tank dry because this will result in a burned out glow plug from the fuel mixture being too lean and can also lead to damage from high engine temperatures.

Shut off the engine by pinching the fuel line to the carburetor and let it cool down for about 10-15 minutes before you start on your next tank of fuel.

Tank 2
Advance to half-throttle for 2-3 seconds for the second tank of fuel. Remember to accelerate smoothly through the entire break-in process. Do this repeatedly as long as you have fuel. When the second tank is done repeat the shut-off and cool-down steps as you did in the first tank of fuel.

Tank 3
On the third tank of fuel you will run for a 3-second count at half-throttle then brake. By this time the engine begins to loosen up and the idle may need to be adjusted down.

You will know an idle adjustment is necessary when your nitro RC won't sit still when idling. Use your tuning screwdriver to turn down the idle by turning the idle adjustment counter clockwise to reduce the idle speed. From this point forward you don't have to let your engine cool down between tanks.

Tank 4
For the fourth tank give your nitro RC full throttle for a count of 3 seconds and then brake. If your nitro RC is equipped with a multi-speed transmission and tries to shift into another gear let off the throttle and then brake. When doing a 3 second count on tank 4 remember to accelerate smoothly to avoid doing wheelies or flipping the RC over.

Tank 5
For this final tank of fuel you will repeatedly accelerate to full throttle in 3 seconds and hold for 2 seconds then brake. After this tank is done you will have completed the break-in process.

Maintain Your Nitro Engine After Break-in
After break-in and after each session with your nitro RC you'll need to perform after-run maintenance. For a nitro engine this includes :

* Drain the fuel tank
* Clean and oil the air filter
* Add after-burn oil

BlueBird Technology Servos & Products

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Saturday, May 19, 2007

RC Kites - Some call it IFO

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Tuesday, May 15, 2007

Dreamz....

....In my Dream, my Angles tell me I cannot fly, cos' I aidn't got Wings ;
I took my Planes out to fly at the Field to join my Angles when I woke upz....




Gyro Confusion?

What is a Gyro?
This is the device that the rudder servo is connected to. The rudder servo connects to the gyro and the gyro plugs into the rudder channel of the receiver. It is used to sense sudden movements of the tail and it commands the rudder servo to compensate for it.

Why Do We Need Them?
Most people think it is to compensate for the wind, but that is not the real reason. I myself give examples of a gust of wind hitting the helicopter from the side, this is to keep the explanation simple but the real reason is to compensate for sudden loads on the main rotor. The tail spins at over twice the speed of the main rotor so if you lose 100 rpm from the head then you dropped over 200 rpm from the tail. The tail rotor is a lot smaller then the main and its effectiveness is highly dependent on the speed. So every collective and cyclic change you make effects the tail. Now keep in mind just because we have highly advanced gyros now does not mean you do not have to take this effect into consideration. Any gyro will work its best when you can keep the head speed constant. This means fine tuning both the throttle curve and cyclic mixing is important to achieving the maximum performance from your gyro.

Gyro Types
Basically you have two types, mechanical and piezo. I do not think anyone still sells the old mechanical gyros but if you bought a used helicopter it is possible you may have one. The mechanical gyros will have a buzzing sound coming from the sensor unit. They use an electric motor with two flywheels, one on each end of the motor shaft. And this is where the noise comes from. To understand how it works hold a spinning bicycle wheel by the axle and try to turn it, you will feel it resist you moving it. The flywheels in the mechanical gyro are mounted on a pivot and a sensor measures the deflection of the motor/flywheels when the helicopter makes a sudden movement. The piezo type gyros work with no moving parts. It uses a triangular crystal with a piezo element on each side. The piezo element is used in a lot of watches to make the beep sound from the alarm function. The material not only can make sound but also sense it. So it is used in both speakers and microphones. Two of the piezo elements on the crystal are set to sense vibration and the third one is setup to vibrate. When the helicopter is not rotating the vibration travelling through the crystal hits the other two piezo elements at the same time. When the helicopter is rotating one sensor will have a stronger signal then the other. It is a very efficient design and has a lot finer degree of resolution then the mechanical type. In addition power consumption is greatly reduced as there is no spinning motor to power.

What is the Difference between Heading Hold (HH) and Standard Rate (Non-HH)?
In Non-HH mode the gyro just dampens unwanted movements of the tail. To keep things simple let say you are hovering and a constant wind hits the helicopter from the side, the gyro will keep the helicopter from suddenly swinging nose into the wind, but the helicopter will eventually drift nose into the wind. All the gyro does is to prevent any jerk type reaction.

In HH mode the gyro will keep the nose pointed in the same place until you tell it to move. You can fly sideways with the rudder stick in the centre and the nose will remain pointed in the same direction.

If you have not used heading hold before then you will notice in fast forward flight that when you make a turn, the tail will not follow the helicopter, you have to give some rudder in your turns. Another thing is that you'll notice the rudder stick feels different. In heading hold, the amount you move the rudder stick from centre tells the gyro how many degrees per second that you want the helicopter to rotate. The gyro moves the rudder servo however much it needs to obtain the requested rotation rate. With a standard rate gyro if you did a slow pirouette (one rotation) with the wind then to keep the helicopter spinning at the same rate you would have to move the rudder stick more as the tail is going upwind and less as the tail goes downwind. But with a heading hold gyro, it will tell the rudder servo to move more or less to maintain the constant rate; you just keep the rudder stick in one place.

Due to typical marketing ploys you will see many names for heading hold. They all are just different names for the same thing. The different names are just because each company wants to make it seem like their version is more special then another companies.

AVCS = Tail Lock = Smart Lock = Heading Hold

Rudder ATV (End Point, Travel Adjust) Values?
On a non-heading hold gyro this function in your radio is used to set how far the rudder linkage will travel.

On heading hold gyros this function works completely different. It is used to set the maximum rotation rate. So what do you do about limiting the travel so as not to allow the servo to bind? Some gyros have a limit adjustment on them that you use to set this. The ones that do not require you to move the ball on the servo arm further or closer to the centre of the arm to limit the travel.

Can I Use Rudder Trim?
If you are using a heading hold gyro then the quick answer is no. The reason is that heading hold gyros are looking for a centred command from the radio to keep the helicopter from rotating. If you move the rudder trim a few clicks one way or the other then a gyro in heading hold mode thinks that you wanting it to spin in that direction.

Example: Say you have switched to non-heading hold mode and the helicopter is rotating left so you add a little right trim until the helicopter is still. Now when you flip back to heading hold then you will find the helicopter now constantly rotates to the right.

So how do you make it so the helicopter is trimmed in both heading hold and non? This confuses a lot of people because they often do the setup out of order. The first step is to centre the trim and zero the sub-trim. Next with the gyro in heading hold mode adjust the sub-trim so the helicopter does not rotate. Normally this should be zero but due to small differences in the radios as well as some gyros you may find you have to adjust the sub-trim. The next step is to switch to non-heading hold and if the helicopter drifts, then adjust the rudder linkage. If the helicopter is drifting left then turn the link clockwise, opposite if drifting the other direction.

Helicopter spins out of control as soon as it gets light on the skids
This is another very common question I get. The cause is the reverse setting on the gyro. Do not get this confused with the reverse settings in the radio, that is not the same. To check the gyro move the rudder stick to the right, the control rod for the tail should be pulled toward the front of the helicopter. Next pick up the helicopter by the rotor head. Grab the tail boom and quickly rotate the helicopter so the nose goes to the left. Watch the control rod, it needs to move forward. If it does not then the gyro is backwards. Most gyros have a reverse switch or jumper located on the gyro, this is not done in the radio. A few gyros require you to turn the gyro upside down.

What is Gyro Gain?
This refers to the sensitivity of the gyro. When the gyro senses an unwanted movement it commands the tail servo to move in the opposite direction to compensate. How much it tells the servo to move is the 'gain'. Ideally the amount of gain should match how much the helicopter was rotated so that it stays pointed in the same direction and does not move. If the gain is too high then the helicopter over compensates. The effect you will see is the tail will bounce back and forth (wag). If the gain is not enough then you will notice the tail does not hold very well. When setting the gain, you want to turn it up until you see the tail 'wag' (bounce back and forth) then turn the gain back down until it stops.

How to Set the Gain?
Gyros with Remote Gain :
This depends on the type of radio you have and how you set it up. Some radios do not have a dedicated gyro function such as the Futaba 6X, 8U (not Super), and JR 622/642/652/662. For these you adjust the gain in the travel adjust (End Point, EPA, ATV) menu. In this menu select the gear channel (channel 5) and use the switch assigned to it to toggle between the gain setting for heading hold and non heading hold. For radios with gyro menus leave the ATV set to the default values (usually 100) and then use the gyro menu to set the gain

Gyros without Remote Gain :
This type will have an adjustment on the gyro. It is usually a small pot that you use a screwdriver to turn.

Gain Values
Different radios treat the values differently. On the Futaba 8U(super) the range in the gyro menu is 0 to 100. From 0 to 50 is one mode (such as heading hold) and 50 to 100 is the other. To fully understand this you have to look at it just as the gyro does. That radio sends a pulse from 1ms to 2ms to each of the connectors on the receiver. From 1ms to 1.5ms is one mode, say Non-HH, and 1.5ms to 2ms is the other. The further it is from 1.5ms the higher the gain. On the 8U(super), 0 would correspond to 1ms and 100 would be 2ms. Now on the Futaba 9C it has 0 to 100 for HH and 0 to 100 for Non-HH. So in the Non-HH position 0 would be 1.5ms and 100 would be 1ms. In the HH position it sends pulses from 1.5ms to 2ms.

Now to add a little confusion some radios allow the end points (ATV) you set to effect the setting you made in the gyro menu. So in other words if you have the gyro menu set at 100% but the end point for channel 5 is at 100% (with a range up to 150%) then instead of sending a 2.0ms pulse to the gyro (for maximum gain) you are only sending a 1.83ms signal which is about 65% of the actual gain in the gyro.

So to help unconfused you now, don't worry about the details. Just set your end points to 100% and 100% for the gyro gain too. Then if the tail wags lower the gain from there. If you have to go below 85% then move the ball on the servo arm in one hole toward the centre and try again.

What is the Delay Setting?
This is a setting found on some gyros such as the popular Futaba GY401. It is used to compensate for slower servos. To set it do a quick pirouette and when you stop watch to see if the tail stops still or bounces. If it bounces then increase the delay to stop it. For a fast servo like the Futaba 9253 leave the delay setting at 0.

Saturday, May 5, 2007

Cessna 182 (Crash)

A begineer plane the Cessna 182. Very stable flight performance & scale looking. Fly well even on Stock setup. However, better performance can be achieved with Brushless setup.

The foam is rather brittle and do not sustain a crash well. Then again, spare parts are available.

Tips 5 : Landing

The most important thing to know about landing a model airplane is that it must land into the wind - just like the real thing. Think back to the section on lift and you can see that wind is effectively free lift that is available for you without using engine power.

To bring your plane in, start by lining it up with the place where you want it to land, either grass or a runway. Then reduce the power, without turning the engine completely off. Use just enough engine power to maintain a gentle rate of descent while keeping the airplane in the landing attitude (that means wheels down - not nose down!), use the rudder to keep the plane in a straight line, allowing it to glide down to the ground gently. Remember that the amount of engine power you need will vary according to the strength of the wind you are flying into - and that can change from day to day.

Some model airplanes have an elevator control. In this case, you can adjust the height, but if your plane doesn't have this feature, don't worry--the engine will do the same thing if you power up briefly to help slow the descent down. Otherwise, it's best to use the elevator to pop the nose up lightly as you touch down, this drains excess speed from the plane.

If you're uncomfortable with landing, turn the engine back on to full power. Then, circle around and try again, lining up again with the runway or grass. Remember that even the experts make mistakes and have missed approaches, and you'll do far better to circle three, four, or five times than to crash your plane. However, you want to make sure you do not run out of fuel or battery power before landing, or the plane could end up somewhere you do not want it to go

Again, thank you for subscribing to this special 5-part report. Hopefully, you have read each of the previous instalments in this series and are now fully aware of five ways you can increase your enjoyment of this great hobby while protecting the safety of your plane and of those people on the ground.

Tpis 4 : Trimming the Plane

The word “trimming” refers to the adjusting of your airplane controls during a flight so that the plane flies straight and level without you making any control inputs. Sometimes a model airplane will want to veer in one direction or another because of the motor's torque or perhaps some distortion or construction defect is affecting the aerodynamics. This may not be critical but you'll need to learn about this characteristic of your plane, and fast, so you can fly it properly.

The small trim tabs located on the transmitter are used to fine-tune the controls. These too can vary from one transmitter model to another. What you are doing is putting in a constant adjustment to the flying controls to balance the defect affecting the airplane.

Once the trim tab has been moved, allow your model plane to fly on its own for about 10 seconds to check that it is flying straight and level, and then, if necessary, you can make further small adjustments until you get it right.

Tips 3 : Taking Off

The way you take off will depend on a number of things. For example, if your model plane is designed with an undercarriage and you’re flying from a flat, smooth surface, then you would do better taking off from the ground instead of using a hand launch. To do this, you go through all of your pre-flight checks and then set the plane on the “tarmac,” facing into the wind.

Next, stand directly behind the plane. Turn the engine on to full power, allowing the airplane to accelerate while on the ground. If necessary, use the rudder to keep the plane headed straight down the runway. Just as with a full size plane, the model will gain speed and eventually lift off the ground.

Lift Off
When the plane starts to take off, give it just a little bit of up elevator. Typically you see beginners make the mistake of climbing too steeply, which causes the plane to slow down, stall, and crash. A gradual climb, as stated before, is much better. So go light on the up elevator.

Launch
If you plan to hand launch your model plane, be sure you never throw it angled up. Instead, it should be thrown firmly --but not too hard--with the nose pointed straight ahead. You want it in a nice stable flying position while you get your hands back on the transmitter box.

Friday, May 4, 2007

Tips 2 : Test Glide

Although not all flyers will perform a test glide at every outing, you will certainly want to consider this whenever you are dealing with a new model. The test glide is designed to assess the glide characteristics of the plane, so you know what to expect if the engine should unexpectedly quit for any reason. To do this, you want to work over a long area of grass, so if something happens, the model airplane will not be seriously damaged.

For the pre-flight check, turn the transmitter on first, followed by the receiver switch. Then, pull the transmitter antenna out so that it's completely extended. Next, make sure the rudder or elevator is working properly, moving in the correct way then centre it in a neutral position.

Now hold your airplane facing away from you, at head level and into the wind. Very gently launch the plane from your hand, making sure it is level or pointed slightly downwards. If the plane is right and ready to fly, it will gently glide to the ground after a short, smooth flight.

Tips 1 : Weight and Balance

For RTF kits (that's Ready To Fly), you don't need to worry much about the weight and balance when you first buy the plane. However, you should always check the balance before each flight. If the airplane is not balanced, it will likely crash. Planes, whether model or full size passenger jets, all have a center of gravity which must be within certain limits for the aircraft to fly successfully.

This has a direct impact on the plane's balance. As a general rule, the center of gravity should be about one-third of the way back from the front edge of the wing (and two-thirds of the “wing-chord” forward from the trailing edge). To test, place the tips of your index fingers under the wing tip, about one-third of the way back from the leading edge.

Then, very carefully, lift the model airplane up, balancing it on your fingers. If the balance is good, the plane will be level, with the nose pointing horizontal, or maybe just a bit downward. If the plane's tail is pointing downward, then you have a balance problem and should not fly the plane until it is fixed.

Before adjusting it, think of what might have caused it. If you tested your model before leaving home and it was OK but now it isn't then what might be the cause? A loose screw or piece of material which has moved around during transit can be enough to affect the CG. If you now adjust it back to balance by adding another weight then you may have left a loose item inside your model which will surely come back to haunt you when it moves again during a flying manoeuvre.

If you are sure you have nothing loose and you do need to adjust the CG, add weight to the nose, something like fishing shots, plasticine, or even modelling clay. Add just a little at a time, checking the center of gravity after each addition. (Or, you can move the engine more toward the front.) If you do not want to lose control and maybe crash and ruin your plane, this is a crucial step.

Tuesday, May 1, 2007

Benefits of RC Flight Simulator

A flight simulator is an excellent tool if used properly. The big mistake that so many people make is to believe that the simulator will teach them to fly. A simulator cannot teach anything. They are simply not programmed with that ability. Many software packages have a built-in tutorial that allows the user to step through the functions of the program as it explains how to use each one. The simulator does not have this feature. For instance, the simulator does not explain that stick movements should be gentle and only enough to get the model to perform a maneuver. It does not explain that the model must be controlled into and out of a turn with the ailerons. These are the functions of an instructor. The simulator is a tool to practice the maneuvers that have been taught by an instructor. A student pilot, especially a beginner, can develop some very bad habits while using a simulator that are difficult to break later.

For beginners, flight simulators are excellent tools for building spatial orientation, motor skills, and confidence. For more experienced pilots, flight simulators help in building motor skills required in doing the more difficult maneuvers. The amount of benefit that the pilot can gain from the simulator depends entirely on how well the simulator emulates the model. On most simulators, the flight characteristics can be adjusted so that it more closely emulates the "feel" of the model. None of the simulators have progressed to the point that the flight physics are perfect but they are close enough that they can be of significant benefit.

Dne of the most difficult things to master for the beginning pilot is approach orientation. There is a natural tendency for the beginner to move the stick in the direction he wants the model to go. When the model is moving toward the pilot, the aileron and rudder controls are reversed. This means that in order for the model to turn to the pilot's left, the stick must be moved to the right. Using a simulator allows the pilot to practice approaching maneuvers for hours on end so that it becomes second nature to move the stick in the correct direction for the model to take the desired flight path. After approach orientation has been mastered, all other maneuvers start to become easier to accomplish, especially landings.

The primary benefit of flight simulators is that of building motor skills. The pilot, whether a beginner or experienced, can practice specific maneuvers for hours without having to be concerned about weather, time of day, temperature, or number of people at the field. The motor skills that are developed through hours at the simulator are basically the same as "muscle memory" in golf. This means that the skills are related more to the muscles reacting to a simple command than the brain sending a series of commands to the muscle. For instance, the pilot wants to perform a snap roll with a Giles 202 model. He thinks "snap roll" and his fingers simply move the sticks to the appropriate position rather than his having to think in what position the sticks need to be. The end result of the muscle memory is where modelers get the term "feel" for a model. Since there is no positive feedback system built into a transmitter, there is not true feel for a model. The feel of the model comes from the difference in the expected feel based on muscle memory and the actual feel from the movement of the sticks.

Many beginners do not progress as well as others simply because of a lack of confidence. This is especially true if the student is not able to fly very often due to conflicts in scheduling time to devote to learning to fly. With each trip to the field, he must re-learn some of the things that he has forgotten during his absence from the field. He must again reinforce his motor skills and regain his muscle memory or feel for the trainer. Since his progress may be much slower than that of other students at the field, he may become frustrated and much less confident. The simulator allows the beginner to practice what he has learned to maintain or improve his motor skills and not lose his confidence. When he goes to the field, he will subconsciously think, "I can do this."

If pilots get proper instruction and use the flight simulator to practice what is taught, it can be of significant value in learning to fly or to perfect various maneuvers. It can greatly increase the "stick time" that the pilot is able to achieve in given period of time. It is a tool that if properly applied can help a pilot to progress at a much faster rate than normally possible. Above all, it is up to the pilot to make sure that this tool is properly applied by getting the right kind of instruction and not try to learn on his own.

RC Switch for Radio Control

Parts List
All resistors 1/4w / 5% tolerance, unless otherwise posted.

R1 = 47K
IC1 = MC14013B
R2 = 1K
Q1 = BUZ11, IRFZ42, NTE2395, or ECG2395
R3 = 10K
S1 = on/off switch (optional)
P1 = 100K

Servo Lead
C1 = 22nF

The MC14013B dual type D flip-flop is constructed with MOS P-Channel enhancement mode devides in a single monolithic structure. Each flip-flop has independent Data, (D), Direct Set, (S), Direct Reset, (R), and Clock, (C), inputs and complementary outputs (Q and Q-not). These devices may be used as shift-register elements or as type 'T' flip-flops for counter and toggle applications. The MC14013B CMOS SSI is a low-power complimentary MOS.

This device contains protection circuitry to guard against damage due to high static voltage or electric fields. However, precautions must be taken to avoid applications of any voltage higher than the maximum rated voltages to this high-impedance circuit. For proper operation, Vin and Vout should be constrained to the range Vss [much-smaller-than] (Vin or Vout) [much-smaller-than] Gnd. Unused inputs must always be tied to an appropriate logic voltage level (e.g. either Vcc or Gnd). Unused outputs must be left open.

Description
The circuit, as described above, is a so-called "Radio Controlled Electronic Switch". It can be used to switch on/off anything electrical, whatever it is. Here are a couple of examples : navigation lights, landing gear, sound systems, glow plug driver, bomb release, parachute, search lights, gyros, and so on.

Fig. A shows the regular setup for common accessories such as motors, glow plugs, bomb-doors, relays, etc. If you like to hook it up to a camera, see Fig. B. Note that for the Camera Shutter version the value for R1 and R2 is different (100K). Please note that this system will not work with PCM.

Heart of the circuit is a CMOS Dual 'D' Flip-Flop MC14013B. The input Flip-Flop is designed as a monostable pulse generator by means of R1, P1 and C1 connected between 'Q' and the RESET input, which produces a preset pulse-length set by the adjustable potentiometer and starts at the rising edge of the input pulse. When this monostable times out it's inverted 'Q' signal goes high and clocks the output stage of the Flip-Flop, which is used as a normal type 'D', to sample the input pulse. If the duration of the input pulse is longer than the preset monostable pulse, then a logic high level will be clocked to the output of the 'D' type. A shorter input pulse will cause a logic low to be clocked to the output. In short, both halves of the IC perform two different logic functions.

The output drives the output device which in this circuit is the IRFZ42 TMOS FET. It needs only 2-volt on it's gate to fully turn-on and has an rDS-ON resistance of only 0.028 ohm. To invert the operation of the r/c switch, you can connect R2 either to pin 12 or 13 of the MC14013B. This circuit is easy in design and to built and can easily be done using vector board, vero-board, or whatever. The complete unit measures 5/8" by 1-1/4" but it can be a lot smaller by choosing SMT components, probably 3/8" x 1/2". You can use a case or heat-shrink. This unit is NOT meant as a motor-switch for electric flight.

Adjusting the Switch
To test the unit hookup a light and a battery, making sure the + of the battery goes to the Drain of Q1. Adjust the potentiometer P1 to somewhere in the middle and set the transmitter function of your choice (say the throttle) to the point where you wish to switch the unit. Now adjust the potentiometer P1 to the point the light comes on. If it does, your unit functions properly and you can play with whatever other setup you have in mind. If you intend to use this unit as a on-board glow driver, make sure to use heavy wiring between glow plug, battery and r/s switch. A 'Y'-lead to the throttle servo is required. If you use this unit to switch relays or a small dc-motor, then a 'spark eliminator' diode (1N4001) is required. Cathode of the diode goes to the '+' side of the battery. (See diagram).
At the top you see the Surface Mount version (SMT), measuring 15mm x 17mm!

The IRFZ42 is a TMOS Power FET and can be costly (approx. S$18). Other substitutes like the IRFZ44 will work too. Watch for static discharge with this one!

IC1, the MC14013B, is a CMOS SSI type Dual Flip-Flop. It features a direct pin-for-pin replacement with the CD4013B, NTE4013B, ECG4013B, and others.

The output signal can be inverted by selecting either pin 12 or 13. To make life easier, you could install a miniature on-on switch.

The middle contact going to R2, and pin-12 & 13 to the other two contacts.
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