Many new beginners have the notion that by using nitro or petrol engine, filling a bigger tank of fuel could fly the RC plane for HOURS, and this is not true! Most of the fliers actually fly their planes in the air for half an hour accumulatively and that would be good enough for the fun. Seldom any plane could last more than 10 minutes up the sky per sortie whether it is a nitro fuel or electric powered plane.
I remember those days I bought some Nikko RC cars or trucks for my son and the batteries could only last a few minutes and one had to charge the whole day in order to play again. The technology of batteries nowadays is good enough to send the planes up there for 5 - 10 minutes without much problem. It all depends on how aggressive you fly those planes and also whether it is a glider that could soar with the wind or thermal column at half or even one quarter of the throttle. And the fast charging time with a balanced charger on a LIPO battery will take only 30-45 minutes. Some of the fliers just plug in the charger to the battery of their cars parked near the flying field. In this way, the electric powered planes become a fast and easy toy of great fun without the hassle of the need to charge the batteries for long hours and also to clean the oil from the fuselage of a nitro plane.
Just a word of precaution though, all LIPO batteries are highly inflammable. Never ever leave a charging battery unattended or put LIPO batteries in your car and park under hot sun for a long time. They could simply explode and burn your house or vehicle away!
Most of the batteries are rated by MAH, the bigger the value it is, the longer the battery could last, and it also means the batteries are bigger and heavier in weight. One has to consider the space of the plane and also how such heavier batteries could affect the CG and also the lift of the planes. The number of cells of each battery is denoted by 2S, 3S, 4S etc. Each cell is 3.7 V and when connected in series, 2S means 7.4V and 3S is 11.1V, so on and so forth. Small and light planes are normally using 2S, while mid size planes are usually using 3S and above. 4S, 6S or even higher S are commonly used for those ducted fans fighter plane models.
I have the tendency to fly electric powered planes more nowadays because it is clean and neat, just charge a few batteries at home, and you are ready for the flight!
Saturday, March 3, 2012
Thursday, March 1, 2012
Common mistakes when flying a RC plane
Setting up a plane to fly is a meticulous task. I had always under-estimated a lot of little things which I thought were just trivial. When the elevator or the ailerons control surfaces were not fully level or flush, I thought that would be alright and I could perhaps trim them while in the air. Many a times, the planes never get to leave the ground high enough before they crash!
Try to bring along a few planes so that you do not end yourself in a frustrating situation with one faulty plane after driving a long distance to the flying site. Under such circumstances, you have no other choice but try to fly it despite all those small things not in order, which you know the plane is not good enough to be up in the air. If you could not fix it there and then, choose another plane to fly instead.
Other common mistakes include the reverse of the control in one particular channel which could cause a plane which is supposed to go up but plunge downwards; instead of turning to the right, going to the left etc. Do remember this simple concept, when a particular control surface when moved upwards towards the sky by the servo, it means to say more air is passing through and thus reducing the lift that makes the plane staying afloat, therefore it will make that part of the plane sinks as a result of it. So when the elevator at the tail is pointing upwards towards the sky, the tail will sink down while the head of the plane will be lifted upwards during the take off. Since the controls of the ailerons of left and right are moving in opposite direction, the banking of the plane to the right starts to occur, when the servo moves the right hand side aileron upwards, while the left hand side aileron points downwards towards the ground. In the same manner, the movement of the left hand side aileron upwards will activate the plane to bank to the left side to get ready for a left turn. (For more information on how to turn a RC plane to the right and left, kindly read my earlier written article on the topic). By checking the movement and positions of the control surfaces on the ground when moving your control stick, then you will know the setting of the controls is correct, if not just use the program in the radio transmitter to reverse and rectify it.
We have the tendency to forget the rudder most of the time, though we normally use it to navigate the plane right and left just to keep it on track to the intended landing spot. We could not use the ailerons to turn anymore in the landing mode because one has to keep the ailerons flush with the wings on both sides once the plane is flying level without tilting to either side when approaching the landing path. Now try to visualize that when the plane is banking 90 degrees on a "knife edge" style of flying, the rudder now acts as an ELEVATOR and the elevator becomes a rudder. Thinking along that line, turning with the aileron together with the rudder at the same time in the SAME direction of the normal sense, thinking we could get a double turning effect from two control surfaces combined would possibly land us into trouble. This could plunge and tip stall the plane. Use the simulator to figure out the effect when using multiple control surfaces at the same time!
One very important part that we must always do, that is checking the CG or center of gravity of the plane. Normally the CG is roughly about one third from the leading edge of the wing, or just under the wing spar. It is better to have a slightly head heavy for a plane to fly properly, it is almost impossible to fly a plane tail heavy. However to fly a RC kite, a slightly tail heavy would be easier to get it manouvred. Always check the CG when you change a battery of different size or weight.
Try to bring along a few planes so that you do not end yourself in a frustrating situation with one faulty plane after driving a long distance to the flying site. Under such circumstances, you have no other choice but try to fly it despite all those small things not in order, which you know the plane is not good enough to be up in the air. If you could not fix it there and then, choose another plane to fly instead.
Other common mistakes include the reverse of the control in one particular channel which could cause a plane which is supposed to go up but plunge downwards; instead of turning to the right, going to the left etc. Do remember this simple concept, when a particular control surface when moved upwards towards the sky by the servo, it means to say more air is passing through and thus reducing the lift that makes the plane staying afloat, therefore it will make that part of the plane sinks as a result of it. So when the elevator at the tail is pointing upwards towards the sky, the tail will sink down while the head of the plane will be lifted upwards during the take off. Since the controls of the ailerons of left and right are moving in opposite direction, the banking of the plane to the right starts to occur, when the servo moves the right hand side aileron upwards, while the left hand side aileron points downwards towards the ground. In the same manner, the movement of the left hand side aileron upwards will activate the plane to bank to the left side to get ready for a left turn. (For more information on how to turn a RC plane to the right and left, kindly read my earlier written article on the topic). By checking the movement and positions of the control surfaces on the ground when moving your control stick, then you will know the setting of the controls is correct, if not just use the program in the radio transmitter to reverse and rectify it.
We have the tendency to forget the rudder most of the time, though we normally use it to navigate the plane right and left just to keep it on track to the intended landing spot. We could not use the ailerons to turn anymore in the landing mode because one has to keep the ailerons flush with the wings on both sides once the plane is flying level without tilting to either side when approaching the landing path. Now try to visualize that when the plane is banking 90 degrees on a "knife edge" style of flying, the rudder now acts as an ELEVATOR and the elevator becomes a rudder. Thinking along that line, turning with the aileron together with the rudder at the same time in the SAME direction of the normal sense, thinking we could get a double turning effect from two control surfaces combined would possibly land us into trouble. This could plunge and tip stall the plane. Use the simulator to figure out the effect when using multiple control surfaces at the same time!
One very important part that we must always do, that is checking the CG or center of gravity of the plane. Normally the CG is roughly about one third from the leading edge of the wing, or just under the wing spar. It is better to have a slightly head heavy for a plane to fly properly, it is almost impossible to fly a plane tail heavy. However to fly a RC kite, a slightly tail heavy would be easier to get it manouvred. Always check the CG when you change a battery of different size or weight.
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