Introduction: Quad 250 Build
Before I build my quad 250 build, I must choose my Materials first, this is an important step, and next I will list my Materials.
This is My Materials:
- HobbyKing/Diatone 250mm FPV "Long" frame (FPV250L)
- HobbyKing KK2.1.5 Mini flight control
- Emax MT2204 Motor/Prop/ESC set with the 20A Mini Opto ESCs,
- Tattu 1300mah 4S lipo battery(recommend to use Tattu battery)
- Matek mini PDB (I need the BEC power anyway so may as well do it neat)
- Assorted cabling bits to link the yet-to-be-bought receiver to the flight controller
- Programmer to suit the KK2.1.5 so I can flash on the newest firmware etc
- XT60 adapter to get my old battery charger (LiPo friendly) up-to-date and back to work.
The Frame Kit
I paid AUD7.66 for the frame and to be honest it's good enough to warrant that price but not much more. See by the time you assemble it and realise that every screw is made from really nasty metal (although they are light) and a few mm too short to do the job well it doesn't take a genius to see another AUD5-10 being spent beefing up the hardware. I, however, will persist with using the provided hardware for a bit.
- As you can see theres only about 3-4mm of screw engagement into the posts of the upper/lower deck. The posts themselves are super light ally and the threads were all nicely cut. (the third photo)
- The camera mount fits securely and seems to allow some flexibility for camera choice. I have a super elementary micro-servo based gimbal I could mount there quite easily. (the fourth photo)
- The decks mount to the plastic "X" at four points with the same lousy too short screws. There are two additional holes that I will use with screws and nuts to strengthen things a bit. (the fifth photo)
Anyway it all went together OK - quibbles about short screws aside everything lined up flawlessly and even the landing gear wedged into place (will have to improve on that system I think).
Step 1: The Motor Set
The motors mounted up to the frame arms perfectly, this time the screws included in the EMAX kit were perfect, long enough to fully engage into the motor base but not jam the motor. Two sets come in the kit, long and short. I used the long - the short are probably perfect on Carbon arms.
It was when I mount the props I struck the snag. Literally.
The 6" 6045s don't clear the body of the frame. 5" props are likely to "just" clear so I guess my next purchase of props will be a mix of lengths!
In the mean time I switched the decks to the under-slung location which also looks pretty cool. The other advantage is much easier access to the flight controller this way.
Next Bits (like Wiring)
The whole reason for starting the assembly was to work out positioning and wiring of most of the elements. My ESCs will lay neatly on the arms and I'll direct solder them to the motors. This will be super neat looking. On the other end of the ESC I'll shorten and run each control pair to the flight controller, each length customised to suit.
With the underslung deck I can mount my battery to the bottom deck (inside the frame) with velcro strapping. I'm considering mounting the Matek PDB/UBEC underslung vaguely in the centre of the frame. This keeps the power wiring routed well away from of there signal wiring.
The flight controller will need to mounted slightly rear-of-centre so that the buttons for setup are accessible, and that tiny little screen angled to make it more visible.
Then as per my other thread I started to think about propellers.
Result: Another box of bits ordered from Hobbyking (Mixed 5" Props mainly) Then I thought about my BLHeli EMAX ESCs and figured having the ability to update/flash them could be good.
Result: Arduino Nano ordered via Banggood
Bought a bunch of Props during the week, just some random cheap HobbyKing (AUD0.32 a pair) 5045's and some Diatone triple 5040's - now have 4 complete sets of props to break in my maiden flight .
Also grabbed some cheap micro-servos for the cheap and nasty gimbal (AUD4.95 gimbal, sub AUD4 servos) Remembered (this time) to get a battery strap or two as well.
Then I got really brave and did the update of the KK2.1.5 to Stevies 1.19S1 Pro Firmware.
All went well and while I'm a long way from flying I'm feeling pretty pleased that I can start reading the manual and making some notes on what settings need to be where.
Step 2: Wiring
I stripped off the heat shrink so I could de-solder the signal wires - only 2 as my ESCs are Opto. By customising their length at this end I don't need to play with new connectors at the F/C end. I'm leaving the motor leads long with their 2mm bullet connectors at least until I have worked out the motor rotation directions etc.
I mounted my Matek PDB to the underside of the "X" section. I've used 3M Automotive DS Tape. It's not going to fall off. In this pic you can see I've biased it rear wards and soldered two of the ESC power feeds on. The ESC wires are trimmed to length and protected with heat shrink tube.
The picture is the PDB with all four ESCs soldered. The semi-central location did make wiring easy and I think overall it looks pretty tidy.
On the upper side I've temporarily mounted the F/C on a foam block to let me get the wiring runs the way I wanted. If it's not obvious yet I'm also mounting the ESCs on the underside of the arms (there's shallow recesses in the arm for this).
The F/C input from the RX will the routed on the other side of the F/C giving some balance.
Now that everything has a place I re-heatshrunk the ESCs, cable tied the wiring runs on the arms and generally tidied up.
The ESCs are DS taped into the recess, wiring held with cable ties at each end and then a loop of tape is used.
I've used Loctite on the lower deck screws and will do the upper screws in the next phase of assembly. For the moment I've taken the Gimbal off the front.
I powered up the unit and rather satisfyingly got some beeps from the Warning buzzer, and a melody of sorts played on Motor - 2. Not sure if thats normal.
The F/C could see the correct battery voltage.
Overall I'm really happy with my effort.
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