Category Archives: RC

Bonsai Maiden Flights/Crashes

Brought the new wing out to a field and gave it a go; seems to fly well! I moved the servo arms back one notch from neutral as the flaps seemed too low and I couldn’t trim enough to eliminate the problem. I also adjusted to 30% D/R on the remote which helped a lot in the later flights.

Wing took the crashes amazingly well on the whole though the final crash resulted in the battery pulling out the piece of wood its glued too. I imagine I can just switch to strapping all the way through the wing to fix it though.

Hobbyking Bonsai – Assembly

Assembling the Bonsai with the parts I selected required a few tweaks.

Servos

Servo

First off, I had to enlarge the servo holes. I left the outside and forward edges of the stock holes alone, taking material off the other two sides to make room. I left the holes ~1/8″ undersized to ensure a snug fit which seemed to work well. I used the third hole from the inside on the servo and the top hole on the flap. According to flite test you want 15mm of flap movement for high rates and 8mm for low rates; the positions I used provide ~25mm at full range so I will have to program the controller down to achieve the targets. Using closer hole son the servo looked like it would start to interfere mechanically.

I did have to slightly enlarge both the holes with a small drill bit to get the pusher rods in.

When using the heatshrink to connect the carbonfiber rod to the Z bends, I added a little superglue as otherwise they seemed apt to come apart.

Motor

Motor Mount HolesEnlarging for Motor

The stock pre-drilled holes for the motor mount were not spaced appropriately for my motor. I used the motor’s mounting plate as a template and, using a very small drill bit, drilled new holes. The nut securing the motor shaft seemed to poke a bit too far back; to provide it some clearance I drilled a hole from the top then enlarged it slightly with a file.

Also, the bullet connectors I purchased were the correct diameter but not deep enough to fully seat the motor’s connectors. I simply resoldered the new connectors onto the motor so everything mated well.

Winglets

Glueing Winglets

My patience is pretty short and the super glue pretty slow to set so I propped the wing up on 2×4’s and used some weights to hold the winglets in place while the glue sets. Given the slight texture on the foam I’m not sure superglue will hold that well (doesn’t like to bridge gaps) but I started with it and will use the same setup to gorilla glue it should they break off.

Receiver

The 8 channel receiver I purchased is notably too large for the application. I stripped the case off of it which seems to get a decent fit. As it filled the compartment out I did have to cut a small notch to provide clearance to actually plugin the servo’s and ESC.

Looking at the back of the plane, the left servo is connect to Channel 1, the right servo to Channel 2 and the ESC/throttle to Channel 3. I followed this youtube video for setting up Elevon Mixing:

RC Flying Wing

I decided to add an RC plane to my flying collection. After a bit of research I settled on the Hobbyking Bonsai.

Based on others success/recommendations I went with a slightly larger motor, battery and servos than the hobbyking recommendations.

Installing the servos actually required enlarging the stock holes. I used an exacto knife to enlarge the holes but kept them ~1/8″ narrower and shorter than the actual servo to ensure a snug fit. I kept the outside and forward edges in the stock location removing material on the inside and back edge.

Installing the motor similarly required drilling fresh holes as the stock ones were not correctly spaced.

Flite test recommends smearing shoe glue onto the leading edge to make it a bit more robust which I have done. I went with a pretty thin layer that extends back ~1/2″ to 3/4″.

The full list of parts purchased was:

 

Mini/Micro Quad Options

I did some more research on mini/microquads as I worked on building my ~$18 version and actually found some very strong prebuilt options:

$39 WLtoys V939 Beetle 2.4G 4CH Quadcopter Dexterous Mini UFO BNF

This one is ‘Bind and Fly’ you can bind it to the Turnigy 9x remote. Its a micro quad so flyable inside and, in light wind, outside. Very similar to the $18 quad I’m building; but already built!

I purchased a V939 and have played with it a bit. Its fun but compared to other models it certainly isn’t my favourite. Still, given its small size it is likely the best choice if you plan to do mainly indoor flight.

$39 Syma X1 Series 2.4G 4CH 4-Aixs RC BumbleBee UFO Micro Quadcopter

A mini-quad, a bit big for indoor use but actually quite usable outdoors. We purchased a few of these at work and they are surprisingly robust (though given our abuse not indestructible). If you do break something spare parts are quite reasonably priced which is nice.

Includes a remote but can, apparently, also be bound to the Turnigy 9x if one desires.

Having now tried additional models; I’d say the X1 is a good introductory quad but you are likely to outgrow it pretty quick. The cost still makes it appealing but if you can spare the extra $10 I’d get the v949 listed next.

$52 WLtoys V949 Upgraded V212 2.4G 6 Axis RC Quadcopter RTF Mode 2

Again a mini-quad, the general design/parts is extremely similar to a pepped up X1 but this unit comes more highly recommended as the flight controller board is apparently notably better as is the included remote.

Unfortunately, you cannot bind this quad to the 9x as it isn’t a compatible protocol. Otherwise looks like a great choice. You can upgrade the propellors to GWS EP 5443 for front and back to notably improve the performance.

Having played with this one a bit I’d say its the clear winner if you’re looking to just purchase something with a remote. The only nock I’d give it is the lack of 9x remote compatibility.

$32 WLtoys V949 Beetle RC Quadcopter Mini UFO BNF

This appears to be a previous generation V949 and will bind to the 9x remote. Being bind and fly it doesn’t include its own controller. It seems like this one is getting difficult to find; I’d probably pass on it given the difficulty in being certain you’ll receive a 9x compatible unit.

$33 V929 Beetle 4-Axis Dexterous Mini UFO BNF

This appears to be a two generations older V949, largely parts compatible but the older electronics will talk to a 9x transmitter. If you have a 9x transmitter I’d recommend this quad as its definitely compatible. I’d upgrade the props as per the v949 with GWS EP 5443 for front and back.

Overall its quite fun to fly but the auto-flip is a bit annoying. I’m going to adjust the rates down a touch to try and avoid auto-flipping but I’ve also ordered a replacement brushed MultiWii controller to try out which aught to enliven it even further.

Practice Quadcopter

As my videos may have indicated; although my tricopter is working reasonably well my piloting could still use some work.

I decided to get a mini/micro quadcopter that will work with my existing controller to learn on as they are so light weight crashes don’t seem to bother them.

After a bit of research the $18 diy quad by dave1993 looks like a winning option.

The recommended parts are:

  • WLtoys V939 RC Quadcopter Spare Parts PCB Receiving Board V939-05 $8.90
  • UDI U816 U816A Hubsan X4 RC Quadcopter Spare Parts Blade Set $1.20 (get 2+)
  • 5pcs x Coreless Motor Helicopter Motor DIY Part Size: 7×16 shaft=1mm $6.65
  • 300mAh Li-Po Battery $3.60 (get 2+)
  • Charger $2.90

Total for just the copter bits (no battery) was $16.75, with battery and charger you’re at $23.25, $28.05 with spare battery and props. Pretty cheap for a usable looking quad thats compatible with the 9x transmitter!

If you don’t already have a transmitter a cheap compatible option is the WLtoys V929 V939 V949 Beetle 4-Axis Quadcopter 2.4G Transmitter E728 $14.85. Its the same one pictured above. I don’t know what the quality is like on though it certainly appears to work.

You can also get the V939 bind and fly (so it doesn’t include a controller) pre-built. Its actually quite cheap on its own at ~$30.

Tricopter Flight Control Board

The hobby king KK2 board looks like a good low cost option at only $30. If you just want something cost effective and simple this seems a solid route to go.

Longer term though; I like the idea of autonomous flight capabilities and, even when manually controlled, the ability to automatically return to the launch site should something go awry.

To achieve these goals, the Ardupilot system looks quite good. Direct from DIY Drones, the creator, it costs $180 + shipping. RCTimer sells a copy called the ArduFlyer for $89.99 they also sell the u-Blox CN-06 GPS Receiver V2.0 for $26.99 ($116.09 + shipping total). Their version seems well reviewed so I opted for it given the savings.

Based on comments it sounds like the GPS receiver from RCTimer isn’t optimally configured out of the box. If you install uBlox’s u-center software and upload the 3DR-Ublox.txt configuration file as documented here it appears to get a lock faster and the baud rate is increased from 9600 to 38400. You will need a 5V TTL to USB adapter; I used a CP2102 Module USB to USART(UART) 3.3V TTL USB To COM which was $2.80 shipped from ebay (it works with 3.3v or 5v devices).

You will need to use some jumper wires to connect the GPS to the TTL/USB adapter as the pinouts aren’t quite the same. Also, note you want to connect TX -> RX and RX -> TX for them to communicate properly. Going TX to TX and RX to RX will not work.

I found loading the settings to the GPS would make it ~3/4 of the way through and then error out. I believe this is due to the baud rate of the GPS changing partway through the config loading. To get around the problem I initially set the u-center software to 9600 baud and loaded the config as far as it would go. I then swapped to 38400 baud and re-loaded the full config; this second runs seemed to complete without issue.

I found this guide quite helpful for getting the arducopter mission planner software installed and setup. I attempted to install the latest tricopter firmware on my ArduFlyer before connecting to it as they instruct. I found the auto com port detect seemed flakey but after manually selecting the correct port (9 in my case) everything seems solid.

Transmitter

A number of people recommend the Spektrum DX6i transmitter for use with tricopters. It appears to go for around $110 shipped and, as the name implies, has 6 channels.

Further research indicated the Turnigy 9x is a better buy. It is only $54 from hobby king and comes with an 8 channel receiver. This transmitter utilizes an atmel microcontroller and has aftermarket er9x firmware available. Additionally, it is very popular to mod (backlight, better radio module, etc.)

Hobby King also provides a newer Turnigy 9xr. This model aesthetically didn’t appeal to me as much. Apparently it also has less internal space for putting in mods and isn’t quite as ergonomic.

Tricopter – Airframe Selection

The RCExplorer Tricopter V2.5 appears a strong option. Unfortunately, when I was ordering bits the motors they recommend were not in stock. Not wanting to munge my motor/esc/batter mix, risk being under/over powered or otherwise messing up, I decided to skip this design.

Upon further research the INFINITY T3 – DIY Carbon Fibre Tricopter looks like a great option. It appears to have excellent 12-15 minutes of battery life and looks to be an excellent platform for putting a GoPro on.

The official design is made primarily out of carbon fiber. My initial go of it will be out of wood to reduce expense when I inevitably crash it. Once my flying skills improve I’ll upgrade the frame.

The T shape appears to provide better visual orientation than the Y designs which is a plus.