Weekly Beginner's Taxiway 2020-11-27

Reviews, thoughts, and events from the week in RC Airplanes

Term of the Week - Servo

Servos are what allow you to control and pilot your aircraft. The servo takes the decoded electrical pulses from the receiver and performs the desired mechanical function. Servos activate the landing gear; they move the flaps, ailerons, and elevator. The servo connects to the receiver with a 3-pin connecter, and the electrical pulses are decoded in the servo and move the servo arms through the gears.    

 The servo consists of a small motor, gears, and a servo arm attachment secured to the servo wire. Servos are denoted by how much weight or force they can actuate. According to Wikipedia, “if a servo model is described as “0.2 s / 2 kg”, that should be interpreted as “This servo rotates the shaft for 60° in 0.2 seconds, and it is able to pull up 2 kg weight using a 1 cm radius pulley”. That is, that particular servo model rotates the shaft with the angular speed of (2π / 6) / 0.2 s = 5.2 rad/s while producing 2 kg × 9.81 m/s2 = 19.6 N force at 1 cm distance, i.e. it produces 19.6 N × 0.01 m = 0.196 N m torque.” https://en.wikipedia.org/wiki/Servo_(radio_control)

There are two construction types of servo gears, metal, and plastic. A good rule of thumb is that a plastic servo will typically have a useful life of approximately 100 hours. If a servo is going to fail, generally, the failure relates to stripped gears. Stripped gears are more likely with a plastic geared servo vs. metal. 

Hard landings or a crash typically cause stripped gears.

 Tip – When you have a crashed plane, always test the servos to see if they are functioning and save them. Most are interchangeable.

 Plane Reviews and Tips

 FlightTest has a great post on 8 ways to improve your RC flying skills. We can all learn from these.

Pilot Ryan Media - Looking for a beginner EDF jet? Check out this video review of the Eflite Viper 70mm EDF Beginner EDF Jet Maiden with Capt. Mike 

Check out these kids. It is refreshing to see talented young people in the hobby. 

A tool of the Trade - Servo Tester

My servo tester is a crucial tool. A small 4.8V (4 Cell) 2000mAh NiMH battery powers the servo tester and allows you to test/actuate a servo to see if it is working or center the servo. A servo tester typically has three settings, manual, center, and automatic.  

 Using a servo tester is safer and more efficient than hooking up a lipo battery to supply power to the servo. The only way a servo can be tested is with applied power. 

Connecting the 3-pin connector to the servo tester and activating the tester will allow you to test the servo safely.

 Here is a link to the $9 servo tester I use. 

 Servo testers and inexpensive and a must-have tool.

  Until next week safe flying!