17-Sep-2017, 04:04 PM
Having decided that I needed another 4" quad in my fleet, I settled on the four inch version of the Japalura frame from Armattan quads. I've always liked Armattan's frames and this seemed a natural choice.
The parts list includes a Runcam Split, so I was faced with some interesting choices to get everything to fit inside this tiny little frame. Here's what I ended up with:
Frame: Armattan Japalura 4" silver
Motors: Brother Hobby Tornado T1 1407 3600kv
Flight Controller: Racerstar Star4S
VTX: Matek VTX-HV
FPV Cam: Runcam Split
RX: FrSky XSR
As I wanted to get this built before the winter comes, I used some of my VIP5 coupons at Banggood to make sure that everything arrived swiftly and sure enough, I had everything ready to start the build this Friday just gone.
Most of my Friday evening was spent dry fitting things to make sure I knew where everything would go. There was also a fair amount of hunting for screws! The frame only had two M2x8 screws instead of eight, the M2x6 screws that came with the motors were 1mm too long and needed swapping for M2x5 and the screws that Runcam provide to attach the mounting bracket to the Split's camera have heads that are too large to fit into the recesses in the bracket. This would have made the bracket too wide to fit in the Japalura's camera cage, but thankfully I had some small headed M2x3 bolts in my parts box.
The flight controller I'm using is a real all-in-one and has an F4 MCU, Invensense MPU6000 IMU, SPI connected OSD, 1A 5V BEC, current sensor and most importantly, four 30A BLHeli_S ESCs. Unfortunately, there's no dataflash chip for black box logging and neither are there any free UARTs to connect an external one. Hopefully I'll be able to do without black box.
There's so much crammed onto the flight controller, that there are only two UARTs that you can connect to. One is taken up by the S.BUS connection and the other UART is not inverted. I could see that if I wanted to use SmartPort telemetry on my XSR that I'd have to get the microscope out!
I stripped off the heatshrink from the XSR, removed the Picoblade socket, removed the current limiting resistor and smoothing capacitor for the CPPM output and wired the uninverted SmartPort signal to the now unused CPPM pin. Tricky work, but it allowed me to make the XSR thinner and connect four 30AWG silicone wires where the Picoblade socket used to be.
Pleased with my work so far, it was time to get the motor cables protected, get some blue thread lock dispensed and mount the motors to the frame.
You can see the modified XSR down at the bottom left of the picture.
I'm very impressed with the Brother Hobby motors! The strength of the magnets is very obvious when you turn the motor bell by hand. It's really notchy and requires a surprising amount of force to get the motor to turn. I'm starting to understand how these tiny little motors can deliver 750g of thrust on a 4045 propeller on 4S. Other nice things about these motors is the long silicone insulated phase leads and the really smart way that they exit the base of the motor. The overriding impression is one of quality.
Time to get the first layer connected up!
The motor wires go under the flight controller, as does the XSR receiver. Getting the wires connected from underneath was fiddly to put it mildly, but more than worth the effort. I've mounted the XSR antennas on zip ties from the rear arms in the now classic pattern.
So far, so good!
Now it's time to add a Schottky diode to the Runcam Split's power cable, get it connected to the Matek VTX and get the various wires connected to the flight controller.
More to come...
The parts list includes a Runcam Split, so I was faced with some interesting choices to get everything to fit inside this tiny little frame. Here's what I ended up with:
Frame: Armattan Japalura 4" silver
Motors: Brother Hobby Tornado T1 1407 3600kv
Flight Controller: Racerstar Star4S
VTX: Matek VTX-HV
FPV Cam: Runcam Split
RX: FrSky XSR
As I wanted to get this built before the winter comes, I used some of my VIP5 coupons at Banggood to make sure that everything arrived swiftly and sure enough, I had everything ready to start the build this Friday just gone.
Most of my Friday evening was spent dry fitting things to make sure I knew where everything would go. There was also a fair amount of hunting for screws! The frame only had two M2x8 screws instead of eight, the M2x6 screws that came with the motors were 1mm too long and needed swapping for M2x5 and the screws that Runcam provide to attach the mounting bracket to the Split's camera have heads that are too large to fit into the recesses in the bracket. This would have made the bracket too wide to fit in the Japalura's camera cage, but thankfully I had some small headed M2x3 bolts in my parts box.
The flight controller I'm using is a real all-in-one and has an F4 MCU, Invensense MPU6000 IMU, SPI connected OSD, 1A 5V BEC, current sensor and most importantly, four 30A BLHeli_S ESCs. Unfortunately, there's no dataflash chip for black box logging and neither are there any free UARTs to connect an external one. Hopefully I'll be able to do without black box.
There's so much crammed onto the flight controller, that there are only two UARTs that you can connect to. One is taken up by the S.BUS connection and the other UART is not inverted. I could see that if I wanted to use SmartPort telemetry on my XSR that I'd have to get the microscope out!
I stripped off the heatshrink from the XSR, removed the Picoblade socket, removed the current limiting resistor and smoothing capacitor for the CPPM output and wired the uninverted SmartPort signal to the now unused CPPM pin. Tricky work, but it allowed me to make the XSR thinner and connect four 30AWG silicone wires where the Picoblade socket used to be.
Pleased with my work so far, it was time to get the motor cables protected, get some blue thread lock dispensed and mount the motors to the frame.
You can see the modified XSR down at the bottom left of the picture.
I'm very impressed with the Brother Hobby motors! The strength of the magnets is very obvious when you turn the motor bell by hand. It's really notchy and requires a surprising amount of force to get the motor to turn. I'm starting to understand how these tiny little motors can deliver 750g of thrust on a 4045 propeller on 4S. Other nice things about these motors is the long silicone insulated phase leads and the really smart way that they exit the base of the motor. The overriding impression is one of quality.
Time to get the first layer connected up!
The motor wires go under the flight controller, as does the XSR receiver. Getting the wires connected from underneath was fiddly to put it mildly, but more than worth the effort. I've mounted the XSR antennas on zip ties from the rear arms in the now classic pattern.
So far, so good!
Now it's time to add a Schottky diode to the Runcam Split's power cable, get it connected to the Matek VTX and get the various wires connected to the flight controller.
More to come...