Categories
Battery Charger Guide

Battery Charger

LiPo charger needs to be capable of charging a 3-cell battery.  A battery charger capable of balance charging the battery is also recommended.  Balance charging reads the voltage of the individual cells of the battery and charges each cell equally to the other cells.   This feature will increase charging time but will prolong the life of the battery and provide slighter longer flight times.

 

Categories
Electronic Speed Controller Guide

ESC

Castle Creations 35 Amp Brushless ESC

An Electronic Speed Controller, or “ESC” controls the speed of the motor.  ESCs will have a power limit.  The more power an ESC can handle, the larger, heavier and more expensive the ESC will be.  When choosing an ESC, it needs to match or exceed the motor’s peak amperage.  If the peak amperage of the motor is 13 amps, then an ESC rated at 15 amps will be sufficient.  An ESC with a lower rated amperage will overheat and possibly fail.

Some common features of an ESC are a low voltage cutoff.  The low voltage cutoff will cut the power to the motors when the voltage drops to a specific level.  This is a protection feature for LiPo batteries.  If a LiPo battery’s voltage drops below its minimal voltage, it can permanently damage the battery.  The low voltage cutoff protects the battery from dropping below its minimal voltage.

Some ESCs can be programmed to have different throttle responses, adjust the low voltage cutoff limit, reverse the motor’s direction and change the switch rate.

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Electronics Guide The Brain

The Brain

ArduPilot Mega board with soldered header pins

The brain of Scout is the ArduPilot Mega.  This board is based off of the Arduino Mega processor and uses the Arduino IDE (integrated development environment) for programing the board.   This board is capable of auto-stabilizing and navigating Scout.  If a GPS unit is connected to this board, it can then auto-navigate the aircraft to user programmed locations.

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Guide Materials

Building Materials

Uncut piece of carbon fiber from HobbyKing

I have experience with using aluminum, copper, steel, plastics and wood. All of these materials have their strength and weaknesses. The one material I have never used is carbon fiber. Carbon fiber is an expensive material compared to other materials. I managed to find a supplier that sells carbon fiber at prices that are cheap enough for me to use for this project. Carbon fiberʼs strength to weight ratio is far superior to any of the aforementioned materials and therefore perfect for an aircraft.

If carbon fiber is not in the budget, a worthy substitute is Garolite. Garolite is a fiberglass composite that has similar properties as carbon fiber. Garolite is not as cool looking as carbon fiber but at a tenth of the price, it is hard to beat.

I found that the equivalent strength of Garolite is twice the thickness of carbon fiber.  E.g.,  a Garolite sheet with a thickness of 2mm is equal in strength to a 1mm thick carbon fiber sheet.

CNC cut motor mount pieces in Garolite