Speedy Bee 4 in 1 ESC Instructions
Here is a link to the instructions I wrote in RC Groups about using the Speedy Bee 4 in 1 ESC for the 74X-i2a.
So this leads to the next discussion about the ESC's, I thought Broc's idea of using a Drone ESC is brilliant. He opted to use one drone ESC 4-in-1 combo versus using an individual ESC for each motor. I will explain later how we soldered the ESC to make it a PWM esc and not us a flight controller. At first when Broc told me he was using a drone ESC I was a little confused, but it all makes sense. There are several advantages using a drone 4-in-1 ESC versus an ESC for each motor. One - there is not much real-estate inside the wing to mount an ESC for each motor and the airfoil is thin. Two - The ESC is centrally located and easy to get too. Three - If an ESC ever needs to be swapped out, I can do it without tearing up the whole wing to get to the ESC.
I am using a Speedy Bee 55 amp 4-in-1 ESC. With each motor pulling about 15 amps, I am peaking this ESC at 60 amps full power on 5s battery. So for now, 5s is all the more I am going to use until I decide I want to use a 6s Battery.
The plane will carry a 6s, 5000mah all day as light as the plane weighs. This big bird weighs just under 5 1/2 pounds. It is extremely light for its size. There are some modifications being made that will add some miner weight, but that will be another discussion for another day.
Getting back to the motors and fan unit assembly, It is relatively simple. Broc and I are using about any generic 50mm EDF unit that can be purchased from Amazon or Ali Express. The fan unit will fit inside the compression fit cowling. We used no glue to mount the fan unit. We used to fans that spin clockwise and counter-clockwise. The fan blades spin into the fuselage. In other words the clock wise fans are mounted on the left side of the plane while the counter clockwise fans are on the right side of the plane. This was done to assist in stability in the event of an motor failure.
Broc gave me the pylons already assembled, so I am not going to explain the assembly of the pylon as it will have a slight redesign so the pylon can be removed for a motor swap in the event one malfunctions. Right now the pylons are permanently mounted. But you will need a 3mm carbon fiber rod to add some rigidity. The cowling is a 4 piece cowling that screws together. There is a front side, top side that is glued to the pylon , a bottom side and the back side that has the thrust tube and screws to the top and bottom parts of the cowling. The EDF units has damper vibration rings that are printed from colorfabb varioshore TPU. They seem to be very effective. Below are pictures of the assembly.
The Drone 4-in1 ESC was a little tricky to figure out as all I had experience using it with a flight controller. I could not find any information on the internet on how to convert it to PWM, So Broc talked be me through it.
Basically it is easy to do, you just need some soldering skills, The 4-in-1 ESC has pins. You will need to look at the diagram. I use a male PWM servo wire with 4 splits from the signal wire. The GND wire ( Black or Brown) is soldered to the GND on the ESC. The positive wire (red or orange) does NOT get soldered on the ESC. The BEC will power everything. The signal wire (white or yellow) has to be solder to four different pins. Each pin has its own wire that all get soldered to the signal wire. Pins S1, S2, S3, S4 are all motor signal wires that get soldered to the signal (white or yellow) servo wire. I also soldered a battery lead with an XT-60 plug to the ESC. I also soldered a Castle Creations 10 amp BEC to provide power to the receiver, servos and gyro.
To save weight and space, we used 19 AWG magnet wire that is enameled insolated versus a multi-strand silicone insolated wire. The wire lead lengths for the inboard motors are 15 inches and the outboard leads are 26 inches. That will also give a little play to work with. We used 2mm bullet connectors to connect the motors leads, extensions and ESC.
Below are pictures of the ESC build.
