DLE Section : Testing the electronics

Be patient and test your electronics before flying.


Brushless Motor Disassembly

P.S : Before disassembling the motor, if your item carries a warranty, opening and attempting your own repair, will void whatever warranty you have.

 

Motor 01 Rev0

The following article contains a short tips on disassembling the brushless motor. Brushless motor should run smoothly from the lowest to maximum throttle with minimum vibration. We could easily listen to the smooth running noise of the motor without mounting the prop. Crashes from major to minor ones might cause unexpected damage to the motor; causing a rough run and noise, bad vibration and/or even twitching/stuttering at the start of the motor or during lowest throttle. Often, you might be able to hear a clicking or scrubbing noise when you rotate the motor manually. This is caused by the surface contact between the stator and the permanent magnets on the rotor; scratch lines can be seen on the stator and the rotor. Damaged bearings and bent shaft are the primary cause of this phenomenon. However, if the bearings and/or the shaft are replaced immediately, the motor might be restored to normal. Sometimes the motor has already been damaged badly and the phenomenon still present even after replacing the bearings and shaft.

To start disassembling the motor, various tools are required. The safest method is to use the bench press tool, however in this article, the disassembly procedure is done using the tools as shown in the picture below.

Motor 02 Rev0

The first step involves in removing the circlip (E-ring), followed by the collar ring from the rear shaft using the pliers. Be cautious when removing the circlip because it might spring out. If you do not have any spares, do not lose it or bend it out of shape.

Motor 03 Rev0

The second step is to pull and remove the rotor (the bell) from the stator (the body).

Motor 04 Rev0

Notice that there are two bearings attached to the rear end and front end of the stator. The next step is to remove the bearings from the stator. Sometimes, the bearings are easy to remove, and some have a tight fit. Remove one of the bearings using barbeque skewer or any wooden stick to plug out the bearing from the stator. Usually, the front end bearing is easier to remove.

Motor 05 Rev0                        Motor 06 Rev0

After you have managed to remove one of the bearings, use a pin punch tool to push the other bearing out from the stator.

Motor 07 Rev0

Place the stator on the plastic wire spool / solder bobbin and carefully tap the pin punch tool using the hammer until the bearing drops out from the stator.

Motor 08 Rev0

Motor 09 Rev0

Now you can replace the old bearings with the new ones. You might use the pin punch tool to push the new bearings into place. Just lightly tap to prevent any damage to the new bearings.

The next procedure is to remove the shaft from the rotor (the bell). Use the allen key to remove the set screw on the rotor.

Motor 10 Rev0            Motor 11 Rev0

The final step is to push the shaft out from the rotor using the similar pin punch tool technique implemented previously to remove the bearings.

Motor 12 Rev0

Motor 13 Rev0

Now you can replace the shaft with the new one. Carefully tap the new shaft back to the rotor. Make sure the flat surface on the shaft is position directly above the hole for the set screw.

Assemble back the rotor to the stator and followed by inserting back the collar and the circlip to the shaft’s rear end. You are done!

“Unless you try to do something beyond what you have already mastered, you will never grow.”

― Ralph Waldo Emerson


Radio Receiver Antenna Replacement

This is a short tips on radio Rx antenna replacement; in this case FUTABA 2.4 Ghz receiver. Crashes from major to minor ones might cause unexpected damage to your model’s parts. They can be either the model’s airframe or the electronics. One of the examples is the radio receiver or Rx unit which is one of the largest value in your investment.

 

When the model crashed, the Rx unit experienced a considerable huge amount of sudden pull or push force. The mounting Velcro / mounting double-sided tapes might be out of place; pulling the antennas along. The mistake comes when the antenna was secured on the airframe too tightly; the pull or push is sufficient enough to separate the antenna from the Rx unit.

Separated antenna

If we take a closer look at the receiver’s antenna, it requires more than a regular technique to solder the antenna coaxial cable back its header plug to restore the Rx unit back to factory performance.

Coaxial antenna

Therefore, it is much easier and safer to replace the antenna with the replacement parts. In this case, FUTABA provides the antenna replacement parts. The antenna replacement parts come with the header plug, which enable plug-and-play replacement procedure. However, they does not comes with the rubber bobbin ( black rubber ring ); you’ll have to use the originally provided bobbin from the Rx unit.

Antenna replacement parts

Notes : Before disassembling the Rx unit , if your item carries a warranty, opening and attempting your own repair, other than springs and ratchets, will void whatever warranty you have.

Futaba Rx unit

 

 

 

 

The replacement parts can be purchased from your local Great Planes authorized hobby store. Or you may contact directly to Futaba Service Center.

http://www.futaba-rc.com/techsupport/service-center.html

 

Strips of paper on tapes allow the antenna to be fastened in place, but easily remove if the receiver is accidentally displaced from its mounting location during a crash. This will prevent any unexpected antenna damage from a sudden pull or push.

Strips of paper on tapes

      Antenna placement

” Every new beginning comes from some other beginning’s end.” – Seneca


Why UBEC is required ?

An introduction of UBEC to your electrical system might save your model from an unexpected outcome which may lead to uncontrolled plunge and crash into the ground.

 

 

UBEC 01 Rev0

In the basic electrical system setup of model, the ESC has a built-in BEC. The Li-Po battery is connected to the ESC which will power-up the brushless motor, the radio Rx/receiver and all the servos. Most of the built-in BEC have a limited ability to supply power to the radio Rx/receiver and servos without overheating/glitch. When overheating / glitch occurs, the Rx receiver tends to reboot (restart) itself, leaving you unable to control until the reboot process is completed; usually almost 2 seconds. Sometimes during the reboot process, the servos turn to their max travel and then return to neutral position before you can gain control. This will cause your model to maneuver randomly. Your model is still save when the overheating/glitch happens at high altitude, but you will never know when will it happened.

 

 

 

 

Besides the limited ability to supply power, a built-in BEC is commonly a linear type. A switch-mode BEC has a much higher efficiency than a linear type BEC, when using Li-Po battery pack with 4S or more.

    • Linear BEC: a 4S Li-Po battery has a typical voltage of 14.8V, in order to produce BEC output of 5V/1A, the current flow into the BEC is at least 1A, therefore the power on BEC is (14.8V x 1A) = 14.8W. But the useful output power is only (5V x 1A) = 5W, so the efficiency of the BEC is just (5W / 14.8W) x 100% = 33.8%; the remaining power of (14.8W – 5W) = 9.8W is converted to heat energy. This makes the BEC hot and may caused overheating.

 

  • Switch mode BEC: to produce BEC output of 5V/1A, the current flow into BEC is only 0.38A (actual test data from EMAX UBEC manual). The power on BEC is (14.8V x 0.38A) = 5.6W, therefore the efficiency of the BEC is (5W / 5.6W) x 100% = 89.3%.

Therefore, adding UBEC with switch-mode BEC to your system will improve the reliability and performance of the model. There are 2 condition of installing UBEC to the system:

   1. The ESC has no built-in BEC.

The UBEC’s input cable is connected to the battery and the output cable to the radio Rx/receiver (batt channel). No change is required in the ESC connection.

   2. The ESC has a built-in BEC.

The built-in BEC of the ESC needs to be disabled; remove the red wire from the output cable of the ESC (the three-colours-cable which is connected to the Rx receiver). The UBEC’s input cable can be connected to the same Li-Po batt which is used to power up the ESC. This can be done by connecting the UBEC to the Li-Po batt’s balance plug. The header of the UBEC’s input cable is required to be changed to the proper Li-Po batt’s balance plug header.

UBEC 02 Rev0

 

“Don’t be satisfied with stories, how things have gone with others. Unfold your own myth.”

      ― Rumi, The Essential Rumi


Flaperon Mixing and 3-Pos Flap Switch

Quick Tips on how to setup Flaperon mixing on Transmitter and the implementation of 3-Position Flap mixing switch.

Note that JR PROPO XG-7 transmitter is used in this case. However, this method may be applied to the different manufacturers or types. Please refer to the manufacturers’ manual on flaperon mixing on each respective brand.

 

 

These tips are implemented to enhance your flight experience and ease the TAKE-OFF and LANDING procedures for your model. Flaperons are the combination of Ailerons and Flaps; the ailerons of the model can be functioned as the flaps as well, and during the flaps engaged, the ailerons can be function normally to control the roll of the model. This method enables the model with only Ailerons to function as flaps as well.

In order to enable the flaperons, transmitter mixing program is required. Firstly, enter the [ SYSTEM LIST ] menu ( by holding the [ ENT ] button while turning ON the transmitter, for JR PROPO).

System list

Secondly, scroll down to [ WING TYPE ] to enable the [ FLAPERON ] (default setting : OFF).

Wing type

Thirdly, return to [ MAIN SCREEN ] and enter the [ FUNCTION LIST ].

Main screen

Function list

Fourthly, scroll down and enter the [ FLAP SYS. ] to configure your desired 3-position flap mixing switch settings. FLAP is the angle amount setting on the ailerons, and ELEV is the angle amount setting on the elevator.

Flap system

 

 

FLAPS MIXING SWITCH:

 

POS.1 [ NORM ] for LEVEL FLIGHT position:

—–>   set FLAP and ELEV to 0

 

POS.2 [ MID ] for TAKE-OFF position:

—–>   set FLAP to moderate amount of down angle ( 15° – 25° )

—–>   set ELEV to small amount of up angle ( 10° – 15° )

 

POS.3 [ LAND ] for LANDING position:

—–>   set FLAP to more down angle than previously ( 30° – 45° )

—–>   set ELEV to less up angle than previously ( 5° – 10° )

 

The numerical value of each setting must be adjusted to your own model, as the characteristic of each model differs and every user has their own preferred style of settings.

 

Finally, before flying your model, it is recommended to test the function of the flaperon mixing system. Make sure the servo connections are already correct for FLAPERON mixing; refer to the diagram below.

Receiver Connection Flaperon

 

For different brands and types, please refer to the manufacturer’s manual.

 

Use the 3-position flap mixing switch to engage the flaps; TAKE-OFF, LEVEL FLIGHT, or LANDING position.

 

3pos flap switch

 

Here is the TAKE-OFF position:

 

Takeoff

 

Here is the LEVEL FLIGHT position:

 

Level flight

 

Here is the LANDING position:

 

Landing

Here is a quick demonstration video:

 

 

 

Fly with confidence!

 

“Confidence is ignorance. If you’re feeling cocky, it’s because there’s something you don’t know.”

      ― Eoin Colfer, Artemis Fowl


Check and test your electronics

 

 

A.      The efficient practice is to test run the electronics system before assembling to the plane’s body.

  • Check for functionality of each electronics. Make sure to check motions for both directions. (CW and CCW for servos and motor rotation)
  • Check for excessive / unusual heat; possibly caused by short circuit or incompatible electronics spec/combination.
  • Check for servo gear; it might occur that the gear has already damaged / defected.

 

Test before ass Rev0

Notes: make sure the propeller is unattached during the motor’s functionality test. Fast rotating sharp propeller blade may cause serious injury.

Motor Test Rev0

Test before ass 02

 

 

B.      Conduct another test run after assembling to the plane.

  • Check for proper direction and motion; servos operating directions for control surfaces, propeller rotation direction.
  • Check for the transmitter channel configuration for control surfaces, D/R and Expo curves settings, fail safe settings, etc.
  • Check for the propeller proper face direction; tractor or pusher configuration.

 

Test before ass 03 Rev0

Test after ass

 

C.      Conduct final test on the field, before taking off.

  • Check for the right transmitter control configuration; ailerons, elevator, rudder direction configuration.

 

Transmitter setup

 

“Good checklists, on the other hand are precise. They are efficient, to the point, and easy to use even in the most difficult situations. They do not try to spell out everything–a checklist cannot fly a plane. Instead, they provide reminders of only the most critical and important steps–the ones that even the highly skilled professional using them could miss. Good checklists are, above all, practical.”

     ― Atul Gawande, The Checklist Manifesto: How to Get Things Right