How To Choose A Fixed-wing Servo? Beginners Must Read The Difference Between Metal Teeth And Plastic Teeth

Playing with fixed-wingservos sounds exciting, right? Many people have just started to get involved and happily bought a bunch of equipment. After installing it and flying, they found that either the plane was dangling in the sky as if it was drunk, or it could not fly at all. They could only carry the wreckage home, and their sense of accomplishment was instantly shattered. What is going on? In fact, the problem probably lies in that small steering gear. Don't look down upon it, it is the key that directly connects the movements of your hands and the attitude of the aircraft in the air. If you choose incorrectly, install it incorrectly, or adjust it improperly, it will all be in vain.

Why is the steering gear so important for fixed wing?

You can think of aservoas the "muscle" of a fixed-wing aircraft. Your remote control sends commands just like your brain sends out ideas, and the steering gear is the muscle that executes this idea. It pulls the connecting rod to deflect the ailerons, elevators, and rudders, so that the aircraft can turn, climb, or descend obediently. If this "muscle" is weak or the response is half a beat slower, the aircraft will naturally be sluggish and operate very awkwardly.

If the muscles simply become stuck and stop working, the plane will be completely out of control. So, don’t underestimate these little boxes. Their performance and reliability directly determine whether your flight will be enjoyable or miserable. When choosing aservo, you really can’t just buy one that works.

How to choose between metal tooth and plastic tooth servos

Novice friends are most likely to struggle with this issue. Plastic gear servo, as the name suggests, the gear is made of plastic. The advantage is that it is cheap and has a certain degree of toughness. It can absorb impact and protect the gear itself in less serious collisions. But its shortcomings are also obvious, that is, it is not wear-resistant enough, it is easy to have empty spots after being used for a long time, it has a large frame when flying, and it feels fuzzy in the hand.

Metal gear servos are much stronger, have high precision, fast response, and still feel tight after being used for a long time, making them suitable for pilots who pursue precise control. But it also has costs. First, it is expensive. Second, if the impact force is too great when the aircraft explodes, the force will be directly transmitted to the motor and circuit inside the servo, which may damage more core components. My suggestion is that good-quality plastic teeth are enough for entry-level aircraft. When you want to fly more accurately and violently, it is not too late to change to metal teeth.

How to judge whether the torque of the steering gear is enough?

This is a good question. If the torque is not enough, the aircraft will move softly. When the wind is strong, the rudder will even shake on its own. How to judge? A simple method: connect the connecting rod and the rudder angle, gently break the rudder surface with your fingers, and feel the force of the rudder against your movement. If it can be easily broken, then it will definitely not be able to be moved when it encounters the pressure of airflow in the sky, but this will not work.

A more scientific approach is to look at the parameters. The torque unit of the steering gear is usually kg·cm, which means how many kilograms of weight the steering gear can pull at the end of the 1 cm long steering arm. For a general training machine of about 1.4 meters, 2-3 kilograms of torque is enough; but for a real machine or a 3D stunt machine with a large steering surface and fast speed, a torque of 5 kilograms or even more is needed. Remember, it’s better to go big than small, and it’s always right to leave some margin.

What is the relationship between steering gear speed and aircraft response?

The servo speed is usually expressed in "seconds/60 degrees", which means how long it takes for the servo to turn 60 degrees, such as 0.12 seconds/60 degrees. The smaller the number, the faster the servo turns and the faster your aircraft responds. A novice who has just started flying may think that the faster the servo is, the better? Not necessarily.

A servo that responds too quickly will make the aircraft move very "thiefly", that is, it will be too sensitive. When you touch the joystick lightly, the aircraft will violently move, making it difficult to fly smoothly. For training machines and aerial photography machines, what is pursued is soft and linear response, so just use a servo with moderate speed. Only when you perform stunts and need to roll quickly and change your attitude instantly, you need a servo that is as fast as lightning.

What are the most common mistakes when installing a servo?

Installation is a delicate job, and a few small mistakes can ruin a flight. The most common thing is that the servo cable is not fixed properly and is dangling in the fuselage. It can easily be scratched by vibration, or caught by gears and rudder angles, resulting in short circuit or jamming. Remember to use a tie or sponge to secure the wire to the body.

Another common problem is that the servo is installed in the wrong direction, resulting in insufficient servo travel or uneven linkage movement. Before installation, be sure to conduct a power test on the ground to ensure that when the servo is in the neutral position, the helm is also in the neutral position. Also, do not overtighten the screws that fix the servo to avoid cracking the casing of the servo or causing the servo to deform and become stuck inside. If you feel that the bottom of the servo is touching the fuselage, do not tighten any more.

What should I do if I want the plane to fly stably?

After the aircraft is installed, the final step of debugging is crucial and can directly determine the flight quality. First, reset all the fine adjustments on the remote control to zero, and then install the servo arm on the servo as vertically as possible. At this time, the rudder surface may not be flat yet, so we can fine-tune it by rotating the length of the connecting rod until the rudder surface is completely in the middle position.

️ Next, push and pull the rocker to the maximum angle and observe whether the rudder surface touches the fuselage or other structures. If so, set the rudder amount in the remote control to limit it to a safe range. Finally, remember to check whether the two ailerons are moving in opposite directions and whether the elevator and rudder are in the correct direction. This "ground inspection" takes ten minutes and can help you save hundreds of dollars on aircraft repairs, so don't be lazy.

After talking so much, I wonder if you have any new ideas about the steering gear you have? You usually fly fixed-wing, what is the most troublesome steering gear problem? Is it installation, debugging, or selection? Welcome to share your experience or confusion in the comment area, let's communicate and solve it together. If you find the article useful, don’t forget to give it a like and share it with your friends flying together!