There are many cheap quadcopter frames on market. Big, small, X, H, foldable, good and bad. And choosing a correct frame for a purpose is both hard and critical for further drone performance. One of cheap, and on a first glance, versatile frames, is x525 V3. Is it worth the money?
Well, it’s a hard question. Before I will go to any conclussions, short description of x525 frame.
Material: glass fiber and aluminium
Type: X or +, you can choose, it is symmetrical
Weight: around 385g,
Integrated landing gear with sping amortization
Power distribution board
Landing gear is quite clever and should absorb most of impact force in case of hard landing. In theory it is correct, but my experience says that it does not matter. It maybe works in case of normal, controlled landing. But in case of really hard landing, read as crash, it does not matter at all. It is a useless feature that only breaks, adds extra weight and really does very little. After breaking 3 sets of front landing skids, I just replaced them with some steel wire. Does the same, and weights less. Like I said, useless feature. Continue reading x525 V3 Quadcopter Frame Review
Last week I was, finally, able to perform a maiden flight of my DIY wooden quadcopter (here and here). I will not say it was huge success, but it was a success alright. What went like expected? Well, quite alot. First of all, it flies and has enough thrust to weight ratio to do flips and rolls. And is pretty stable in hover. What went not like expected? It is highly unstable on yaw. Really, really unstable. Probably rear propellers are too close to each other and I have to work on PID settings. As soon as I will have enough spare time…
In a mean time, here is a short video from DeadRat’s maiden flight:
Final configuration goes as follows:
Motor to motor diagonal: 500mm,
Motor to motor front arms: 370mm,
Motor to motor rear arms: 300mm,
Materials: 3mm plywood and 15mm wood spars
Motors: Suppo A2212/13 1000KV
ESC: XT-Xinte 30A
Flight Controller: OpenPilot CC3D (clone)
Battery: Turnigy 5000mAh 3S 25C
Propellers: Gemfan 1045
Start weight: 1212g
Hover time: 21 minutes
Next steps: tune it up and move battery to top. Somehow I do not want to construct a landing gear for it…
Hitting the ground with a drone is not healthy. For pilot’s self esteem and UAV both. Specially when impact’s force will be taken by one of the motors. Most probably it will survive, they are quite tough little devices, but delicate bearing will take punishment and might wear off. Luckilly, signals of damaged bearings are easy to notice: motor starts to make strange noises and you can hear oscillations during maneuvers. At this point you have two options: replace whole motor, or replace bearings.
I faced this situation last weekend when one of my MT2213 935KV BLDC motors stated to rattle in flight. It was very hard to notice in hover, but audible in turns. So I had no other option and decided to replace damaged bearings. Continue reading Turnigy MT2213 935KV bearing replacement
In theory, battery strap should be one of the least important parts of any drone, quadcopter, or any RC device. And no matter what anybody will say, it is one of least important ones. As long, as it keeps battery in place and does not unfasten itself out of nowhere. Especially in flight. So, as an addition to cheap battery straps from ebay/china we can choose something more fancy. Like Turnigy Battery Strap 330mm.
Work on wooden quadcopter from this post continues. This weeken I’ve been able to almost finish. Almost. Frame itself is done, motors and ESC are in place, electric cables soldered, but this wooden multirotor is grounded. The reason is flight controller Thunder QQ Super. Why? Because it is crap. Really. The first unit was broken and 2 motor channels were not working. Fine, it happens. Seller has sent me second unit. It arrived few weeks ago, but I never had time to check it.
Yesterday I finally connected second Thunder QQ Super to radio receiver and motors. And what? One of the motors is not spinning. ESC is only beeping and this is all. After connecting this ESC to radio RX directly, motor spins just fine. There are also no problems with this ESC when used with different flight controller (OpenPilot CC3D). It only does not work with QQ Super. Why? No idea.
OK, this time it’s not 100% Thunder QQ Super fault. It is more like incompability. But very frustrating incompability. Either way, new flight controller should be on its way and in 2 weeks my quadcopter from wood should be fully operational.
I must say I’m happy with results. Frame is lighter than I expected and itself it weights only 256g. With motors and propellers, weight goes up to 615g and 1100g with ESC and battery. So, it’s not light, but not so heavy after all. And it’s very rigid.
motor to motor diagonal: 500mm,
motor to motor front arms: 370mm,
motor to motor rear arms: 300mm,
frame weight: 256g
And it finally has an official name: DeadRat.Why DeadRat? Because it’s a dead cat frame type and we have a pet rat. And my older daughter likes the name very much.
Crashes when flying any RC gear happens. And lower the entry level, more crashes we can see. Like, for example, those two “hard landings” I had few weeks ago.
First one is 100% pilot’s fault. I’ve got lost with FPV gear, lost sense of altitude and just hit that small tree trying to recover. Quad survived almost without a scratch.
Second one is a hardware fault and a proof that electronic components are sensitive to water. BEC got wet during rain and stopped to provide constant voltage. As a result, flight controller, OpenPilot CC3D in this case, was reseting itself on random basis. Result? Uncontrolled and rapid descend. This time quadcopter had taken some damage: broken landing gear. Good thing those things are pretty cheap, but still, it takes time to ship from China. In a meantime, steel wire 1.8mm has to work as landing gear replacement.
After building my last quadcopter drone, I was lest with a lot of spare parts, I’ve decided to invest some time (and money, of course) and build wooden multirotor drone. Od course, not everything would be made from wood. That is kind of impossible. Only frame. Quick research on the internet proven that is fully possible. A lot of people are using wood to build drone frames. If they can, so do I.
Since this project was supposed to be as cheap as possible, I’ve decided to use the same propeller size as my main setup: 10×4.5″, the same radio: Turnigy TGY-i6 and batteries Turnigy 3S 5000mAh 25C. Full planned configuration is as follows:
~400mm wooden frame (plywood and slats) in Dead Cat configuration,
Today was the first day of actual building. After one day I have central plate and front arms.
3mm plywood was too flexible, so I reinforced central plate on edges with additional wooden slates. That gave some extra rigidness on longer axis. Arms are secured using M4 bolts.
I must say, that this frame might be way better than I expected in the beginning. I was surprised how rigid front arms are. And lighter than anticipated. It’s not done yet, but I expect frame’s weight will be around 400g. I’m only affraid if it will survive first crash…
I think everyone who owns a drone would like to be able to test it at home. No wind, no rain, close to computer and all required tool. But… If you do not have a very very big room that might not be a best idea ever. Limited space makes everything extremely dangerous. Specially in case of untested aircraft. Human body is fragile, quadcopter is a delicate device and propellers can spin quite fast. Luckilly there is a way to test at least some aspects of multirotor flight at home. You just need some kind of harness that will prevent drone from getting out of control and smashing into anything.
To create simple harness you will need 4 pieces of rope and something to attach them to. Like chairs. Or table. Or any other furniture. It only has to be heavy enough to support weight of your drone.
In more advanced version, like I did, you can attach to 2 wooden board to a basement/garage walls or bookstand. Just like on a picture above.
Good FPV video is always nice to watch. All kinds: multirotor, plane, flying wing. And some RC fanatics groups are just expected to create awesome videos. Like Happy Flyers for example. Flying in a gravel pit for example.
You want to fly, you need a motor. Electric, internal combustion, jet, ion, gravity. It does not matter. And since gravity engines are not invented yet, ion has no place in atmosphere and jet or internal combustion are kind of non-practical for multirotors usage, we have to stick with electric motors.
In RC world there are two types of DC motors we can choose from: brushed and brushless. The brushed ones are wth us for decades. Cheap and proven, but with a few downsides. First of all, they have brushes and brushes wears off because of friction. After time, they stop to conduict electricity and has to be replaced. Plus, they cause sparks, lowers efficiency, make noise, are sensitive to dust and so on… This is why, we do not use brushed DC motors any more.