The RCT800 is back up and flying after crashing into a river a few weeks ago. After rebuilding almost the entire aircraft it was finally time to strap on a camera and go make a video of a nearby nature conservancy.
It was a nice day and the area was completely deserted but I was taking it nice and easy too! I lost a little confidence after the crash and I am slowly working back to feeling like the aircraft is an extension of my arm again.
Looks like I am on track since the video shows almost no vibration:
I am not sure if you can call it a Phoenix when your bird drowns and then rises from the river to fly again? There was no fire involved but the I recently crashed my RCT800 into a river. Besides losing a few sandals, sitting in the river with the power on also seems to have wrecked 4 of my ESCs and my taken away a little of my confidence .
I’ve finally received my replacement parts and I’ve reassembled the RCT800. It’s looking pretty good with the new landing gear extensions I made from bamboo strips glued together (found black ones so they blend in pretty well). They’ll break if I land too hard but they’re fine for controlled landings and it looks more like a flying spider this way (also cheap!!). Plenty of room for cameras under there!!
Different view (a flying spider!):
Power on a ready to fly!!
Anyway, I’ve now made 3 test flights without issue and in slightly heavy winds… I think I am “back in business” although the incident has me reconsidering suitable places to fly and even considering a pre-flight checklist (never intended to get this serious about it but it might be a must with craft this big!).
It was a beautiful day and a perfect time to make some aerial videos on a sweet marshy part of the Holland River. I wish I had taken some pictures to document the crash but at the time I couldn’t manage it because I was frantically running in a panic! The only real pictures I had of this event are in the Holland River somewhere.
About 2 minutes into a controlled flight my RCT800 became completely uncontrollable (stable mode) and stopped responding properly… while drifting away!! In a panic I threw the RTH (return to home) switch hoping that this function might be able to control the craft when I could not. This caused the RCT800 to start dive bombing the ground before flying up again (like giant Us in the sky). I stood there watching with a feeling of helplessness (and a little horror) for about a minute or 2 until the crash. Anyway, the Holland River really isn’t that big or wide in this area but this was (of course) exactly where my RCT800 ended it’s crazy flight… in the river with a giant splash! You can’t see the river from where I was standing but I saw the splash well enough and started running!! The RCT800 was in the River on the opposite bank from me and 100s of meters away! When I got to the craft some of the props were actually still spinning (slowly) underwater!!
My Cannon Digital Elf – somewhere in the Holland River by Rogers Reservoir Newmarket. This isn’t a scary river at all but on the day in question it had a good current going and there is a nearby waterfall. Decided not to push my luck too much in the River and couldn’t find the camera from shore when it became detached from its mount.
My flip-flops!! There is a mud flat leading up to the River and as I ran for my craft I literally sank up to my thighs in some spots… alas my flippy floppies were claimed by the river bank!!
So far my tests indicate that I’ve got 4 blown ESCs. I bought the DJI 30amp Opto ESCs so this was an expensive crash (around $80) but given what else might have failed I am pretty lucky. I have yet to receive my replacement parts (ordered) but I should be back up and running with this craft soon. I had also made landing gear extensions from wood; these were completely smashed by the crash but they were cheap and home made so not a big deal!
It’s a little difficult to know exactly what went wrong when you retrieve your partially smashed helicopter from a river but I did notice one important point; the GPS mount is made from a fibrous material and the pole seemed a little compromised and bent at one end. It’s not clear if this was from the crash in the river or a prior incident but I think this could have caused the antennae to bend mid flight. This would have caused problems for ALL the flight modes I used while trying to recover the RCT800. Ironically, I did not try full manual mode because I thought it would make things worse and this mode may not have been affected by a bent GPS. You can see the frayed material in this shot. The next version will NOT use an antenna and the GPS sensor will be mounted flat on the airframe to prevent a recurrence. Also, if something like this happens in the future I will definitely be going for a controlled crash if the auto pilot modes don’t work. In hindsight, I let the craft hang in the air for too long when I still had throttle control and could have put it down (crashed) more quickly. The results may have been the same but hitting the river was a complete fluke!
It’s really not much consolation but at some point everyone crashes. This makes safety and aircraft maintenance a paramount concern. If my little crash had happened in a busy area it would have been terrifying and dangerous! Anyway, as it turns out no one has more experience crashing UAVs than NASA (they’ve been doing it since the 60s). A little while back they released an e-book about it… It’s called Crash Course and dissects quite a few of their UAV crashes. Cool toys and expensive crashes these guys have!
Having recently built an RCT800 Hexacopter from parts I have a pretty good idea of what is needed to build a Multicopter and how the parts all fit together. Check out my UAV General Parts List if you are interested in a general description of the parts you’ll need.
There are literally thousands of ways to build a Multicopter now and the list of available parts and websites can be a little daunting. It’s a good idea to start out with a purpose and or goal in mind and then build your list before buying anything. This can help you develop your desired parts list in a way to ensure success. This also lets you enter your craft specs into an online calculator tool like the XcopterCalc calculator which will point out any problems you might have and estimate your flight times.
Naza Flight Controller and GPS
HP4215 630KV 24N18P Multicopter Brushless Motor
DJI Opto 30 ESC
13×6.5″ Carbon Fiber CW CCW Propellers (6pcs)
DJT – FrSky DF 2.4Ghz Combo Pack for JR
ZIPPY Compact 3700mAh 3S 35C Lipo Pack
Lighting and Orientation – Blue, Red, Green
Turnigy Receiver Switch
Not on board Heli
Turnigy 9XR Transmitter Mode 2
DJT – FrSky DF 2.4Ghz Combo Pack for JR
Turnigy 9xr Battery
ZIPPY Compact 3700mAh 3S 35C Lipo Pack
B6AC – IMAX B6-AC Charger/Discharger 1-6 Cells
Connectors 3.5 bullet
XT90 connectors for battery
Parallel Battery Wiring Harness- build or buy
allows two batteries to be used at once
**the list above produces a Hexacopter with great flight control and performance characteristics however I am not necessarily recommending these parts. This was a relatively expensive build and some parts such as the RC Timer 630KV motors have performed a little more poorly than expected (these motors have great performance but terrible prop mounts which introduce vibration into your aircraft).
Every once in a while even the toughest fighter gets beaten. That’s kind of how I feel about my 1SQ. I broke it last week but in reality it had no right to be working anyway after taking the amount of (accidental) abuse it has seen. This has been a great little toy/trainer but it finally gave in last week and needed a little TLC.
This seemed like a relatively easy fix to begin with, the battery wire had become compromised/frayed over time and finally stopped working altogether. Simple right… just solder on a new wire and connector!!?? Anyway, after removing the board from the aircraft I started to remove the battery wire and the “gunk” they insulate the connection with. During this process I accidentally knocked an adjacent resistor off the board too (the little brown thing). This isn’t looking good, its getting worse!!
As you can see above, this was now a 3 step fix and one of the soldering jobs looked a little more difficult.
I had to:
Remove the old battery leads from the board by heating the solder and pulling the leads out (already completed in the above picture).
Reattach the resistor I broke off (this one looked a little scary because the contacts were so small and my thumbs are huge). Pretty sure a machine soldered this the first time.
Reattach the positive and negative battery leads through holes in the board and solder them in place.
Hopefully, you can’t really tell but the end result wasn’t exactly what I intended… If you check it out you can see that I have the resistor on a little sideways (circled in red) and I put the negative lead through from the backside of the board to stay away from the resistor (circled in black). At ant rate, the fix works and seems solid so I decided to leave it.
Plugged the battery in and everything started working like a charm! **Actually I plugged in the motors wrong to begin with and all my Quad would do is flips… If you have the same behaviour you may want to check your motor connections. The picture below is correct and can be used as a wiring reference:
RCT800 FVP Camera Mount Testing (Also known as the last few videos and pictures I took with my Canon Digital Elf before it went swimming and never came back).
The brushless motors I bought from RCTimer (630KV) seem to have one fatal flaw; the motors are great in terms of performance but the prop mounts are poorly milled and or cast. They make it almost impossible to mount your props without causing an imbalance and vibration. This turns your sweet flying rig into a vibrating machine and makes good videography pretty tough (make that impossible… see the last clip) even if your props are balanced.
I’ve been testing various materials to deaden the vibrations and sponges from the dollar store seem to make great (cheap!!) vibration absorption material. In total, I tried rubber bands, paper, duct tape, string, a homemade shock, and two different sponges before coming to a solution. The homemade shock had some promise but it was outclassed by a simple cheap ($1) sponge so I didn’t take it further than a few quick tests.
As you can see from these two test videos the results for regular dollar store sponges were decent (compare these videos to the last one). I found that all I needed was a little bit of sponge between the camera and the aircraft’s hard surfaces. This almost completely eliminated the vibration from the props.
Got pretty high in this video… You can clearly see the river that I later had to wade into in order retrieve my Hexacopter after it went haywire and crashed.
These results are especially good if you consider the movies I was able to make earlier (before adding the sponge).
Here is a sample of those vibrations, as you can see the movie is unusable and a little sponge will absorb quite a lot of shake (the only real difference between the movies above and below is the camera mount sponge padding)
RCT800 – flying at dusk in a local parking lot. Recently modified the LED configuration in order to see them better. Was using the IOC (intelligent orientation control) in Head Free Mode at certain points during the flight. With this mode enabled it doesn’t matter which way the nose of your aircraft is pointing; the direction of the craft is controlled by the right stick (in Mode 2) and the aircraft moves in relation to it’s takeoff point.
Building your own multicopter or UAV isn’t too difficult providing you can do a little soldering and source parts which work well together and meet your requirements. There are many online hobby shops which will allow you to order every part you’d need to make and awesome UAV.
In general, every multicopter will need some version of the following parts in order to fly:
Multicopter Parts list:
An Airframe – It seems somewhat obvious but you will need a frame on which to build your craft. Whether you build it yourself or buy a frame this part will have a large impact on your craft’s performance. Airframes are available in many different shapes and sizes. Generally at the moment airframes are tricopters (3 props), quadcopters (4 props), hexacopters (6 props), and octocopters (8 props).
Flight Controller – the flight controller is essentially the brains of your aircraft. This equipment takes in sensor details and user input to determine what your craft needs to do. There are many different models of flight controller available; each with different capabilities, features, and sensors.
Receiver (or RX) – A receiver flies on-board the aircraft and like the name indicates this piece of equipment receives a signal (user input) from your transmitter and then relays that information to the flight controller.
ESC (electronic speed controller) – controls the speed and direction of the motors in response to input from the flight controller. Each motor you are controlling will need a corresponding ESC to control it. ESCs vary greatly in design and specifications. In multicopters these are essential pieces of equipment because your craft maneuvers by varying the speed of each motor independently.
Motors – If you’re building something that flies it will need motors to power that flight. Motors come in every conceivable shape, size, and power. Selecting the right motor for your application will depend greatly on the purpose, size, and weight of your aircraft (and propellers).
Props (propellers) – Propellers come in almost every conceivable design and size. Selecting the right propeller for your craft is very important because it influences almost every other parts choice you’ll make. Props influence flight time, power consumption, and aircraft flight performance.
Batteries – The power source for your aircraft. Batteries come in many many different shapes, sizes, and capacities. The right battery for you will most likely be determined by the purpose, weight, and intent of your aircraft.
LEDs – LEDs are very useful for lighting and flight orientation purposes.
Wires -of course you’ll need a few wires to connect everything together.
Connectors – wiring connectors are needed for a variety of applications; like connecting your battery to your aircraft in a removable way.
Transmitter (or TX) – a radio transmitter is used to control your aircraft by sending signals from the ground to the aircraft. It doesn’t fly on the craft but its obviously an essential part of the kit.
Battery charger – this is somewhat obvious but you’ll need one of these to recharge your batteries for another flight.
There are several online calculator tools which are very helpful in determining if your parts will work together. A great example is the xcopterCalc calculator; this tool allows you to input your parts specs and find out things like power consumption, estimated flight times, parts incompatibilities, etc. If you are planning to build a multicopter this is a great place to start!
**If you are looking for a specific parts list then please review the RCT800 actual parts list.
The Turnigy Receiver Switch is a neat little piece of hardware (tiny!) which allows you to turn things like LED lights On/Off from a free channel on your receiver. These are also pretty simple to install and use!
Here the switch itself (its tiny)…
The switch is pretty simple and has:
2 Red (positive) Wires
1 Plug for your receiver
So how do you wire this thing anyway?
Its actually quite easy but I will admit that I did this wrong once ;.)
If you check out the wiring diagram below you’ll notice that the correct way to install this switch is by simply wiring it into the positive line of what you are controlling (between the load and the battery). Its easy to install the switch but also easy to over think this too!
Here are the step by steps for setting up this switch. I am not going to discuss setting up your transmitter since there are many different models and possible setups:
The first step is very easy. Find an unused plug on your receiver and plug in your switch. In this case channel 8 was available.
The next step is still pretty easy. Solder one of the red (positive) wires to your power source/battery/wiring hardness.
Now its time to deal with the 2nd red wire coming out of your switch. The positive wire for anything you are controlling with your switch needs to terminate at this red wire. In this case the switch is controlling 4 sets of LEDs on different parts of the aircraft. I started by lengthening the wire to allow it to reach all the LEDs.
Every installation is bound to be a little bit different however the final wiring setup should look something like the picture below:
The switch is secured to the aircraft (circled in purple).
The 1st red wire from the switch attaches to the power source/battery (circled in pink).
Each negative wire for the LEDs terminates normally as it would without a switch (no change).
Now each positive wire for the LEDs only connects to the 2nd red wire from the switch (four connections circled in red).
One of the great features of the DJI Naza-M with GPS is the “Return to home” failsafe. With this feature enabled, its possible to setup a TX so that you flip a switch and your aircraft comes home. In practice this works really well and the RCT800 always lands within ~3m of its takeoff point. It seems to reliably land ~3m North of takeoff. Its also possible to setup the RX (certain receivers) so that the failsafe triggers this function. I’m scared to test it (turn of my transmitter while flying) but the RCT800 has this feature enabled too.
What “Return to home” does:
Craft stops moving
Craft climbs to 20m (above most obstacles and trees)
Craft turns towards “home” and flies there (scared the hell out of me the first time!)
After a brief pause 20m above “home” the Craft slowly lands and disarms
I took the following pictures while using the “return to home” switch on my TX (obviously no hands on the controls).
About 3m north of takeoff (not sure if I’ve got a config problem)… still very good!