After months of researching and seeing what was out there, it was decided to “scratch build” a variant of the popular DJI “Flamewheel F450“. In stock form, the F450 is a mid-sized quadcopter, measuring 450mm motor-to-motor across the diagonal.
However… to optimise payload capability vs AUW (All Up Weight), aftermarket extended aluminium arms will be used.
As well as being stronger, these arms are 2″ longer than stock, and on a unit-length basis are lighter. They will accommodate propellers up to 14″, a significant improvement over the stock 10” propeller limitation.
Therefore, with carefully chosen and suitably rated motors and electronics, more thrust can be realised over a stock F450 kit.
With the 2″ longer arms (2 x 50 = 100mm) across the diagonal, this quad becomes a “550” class machine, although retaining the F450 centre plates.
DJI do offer an F550 hexcopter, but the extra weight associated with two extra sets of arms, motors, ESCs and propellers puts this above my strict self-imposed 2kg limit. Don’t ask!
Parts were ordered last Sunday & Monday, and they’re starting to trickle in. 🙂
From ReadyMadeRC in the USA, Aimdroix arms, Aimdroix landing gear, motor mounts, 4mm bullet connectors, various screws, velcro battery straps, Loctite, propeller balancer, and ESCs (motor Electronic Speed Controllers).
From Hobby King, the iCharger 106B+ and two lipo batteries.
This is a mid priced unit that packs a lot of features, and there are many reviews of this unit to be found on YouTube.
The nominal 15V @ 20A it requires will come from a ham radio power supply… of which there are several here to choose from, both linear and switch mode types.
This charger has a USB port on it, so it’s firmware can always be upgraded, and battery charging data can be logged & plotted on a PC.
Choosing LiPo (Lithium Polymer) batteries is a hard one!
Each brand has their followers, and the marketing spin superlatives never ends, so it can be difficult in choosing something that represents good bang for the buck.
Not being able to filter the plethora of BS from facts, I chose to initially purchase two different brands of the same 3,300mAh capacity.
Why order two of the same, when you can do your own real-world comparisons.
This build is using “3S”.
A single lipo cell is nominally 3.7 volts, so “3S” means 3 x 3.7V = 11.1V battery pack.
2S = 7.4V
3S = 11.1V
4S = 14.8V
Also from Hobby King, Turnigy and Zippy brand 3S lipos.
With Hobby King you have the choice of ordering from their International Warehouse (I’m led to believe is located in Hong Kong), or from the Australian Warehouse in NSW.
The International Warehouse offers much more stock, but delivery from the domestic warehouse is much quicker, and most of the popular items can be ordered from the local warehouse anyway. Ordered Monday, here today (Thursday) via Couriers Please couriers.
The Aimdroix aluminium arms will not flex around like the stock crappy plastic arms will, therefore the craft is expected to be more stable in flight, as is widely reported on the various MR discussion forums.
Aimdroix arms are available from ReadyMadeRC in the USA.
Arms usually come in various colours, as MR pilots use the different colours to indicate which way their craft is orientated. Stock DJI plastic arms come in red and white.
The older versions of these arms (V1.0) are still available, so be careful when ordering. The V1.5 arms have been refined and are marginally lighter than the V1.0 originals.
These Aimdroix aluminium arms are CNC machined, and the finish is excellent. They make the stock plastic arms look rather sad!
ESCs are the recently released T-Motor “S” series, with pre-flashed “SimonK” firmware.
ESCs with SimonK firmware are more suitable to MRs as they offer a faster response to joystick inputs, resulting in more stable and predictable flight.
Many ESCs can be purchased and later re-programmed with SimonK based firmware, but unless you specifically like experimenting, why muck around for the sake of it?
Five ESCs were purchased, as with most electronic “fuses”, it’s always handy to have a spare at a moments notice.
These are rated at 25 amps nominal, with some vague “peak” rating of 35A.
3S power connects to the big red & black wires, whilst on the right hand side, 3-wires from the motor plug into those connectors.
The familiar 3-wire RC lead plugs into the flight controller module.
ReadyMadeRC are brilliant to deal with.
emails are always answered within 24 hours. Their website indicates stock availability, and with out-of-stock items, you can set automatic email alerts on new stock becoming available.
Parts were ordered Monday morning (Brisbane time), and they were on my front door 3 days later, via FedEx.
Postage was a very reasonable USD$28 for what weighed well over 1kg of goodies – compare this to some eBay rip off merchants!
ReadyMadeRC have actually beaten in-stock parts from Australian vendors!
Major components still to arrive include: motors, propellers, the F450 plates, and flight control modules.
Some of these items are on 2+ week lead times.