Hey there folks
This is my first article on Flitetest, I got the RC bug thanks to Flitetest in April this year and have been building multirotors since. I am a novice and my flying ability is still well in the novice range. But I wanted to share my latest build as I had to do a few things differently as I have limited access to building supplies here in New Zealand. I wanted to use stock materials that I could get from the local hardware store
After purchasing a Bat Bone kit and sending via a friend in the USA it finally arrived late last week. So the build started in earnest.
Parts list for the first iteration :
Motors : Turnigy Aerodrive SK3 2822 -1275k
ESC : Q Brain 4 x 20A Brushless Quadcopter ESC 2-4S 3A SBEC
Landing gear : HK-500GT Landing Skid (Align part # H50122) & HK-500GT Landing Skid Pipe (Align part # H50090)
Props : 8x4.5
The key difference is that I used 12mm OD aliminum tubing as the arms. This is readily available in hardware stores here.
The other part that is non-standard were the motor mounts, I got a set of plastic mounts that fitted 12mm rods. I got these from ebay a while ago with the plan to used them on a v-tail design.
Right lets get to the build of Version 1 ...
The unopened Bat Bone kit ready for assembly.
The first modification I did was to cut the corner off the side plates. This allowed me move them up one slot and I didn't need to full cut the side plates as David did in his build.
The side plate cut and sanded.
Above you can see with the corners cut the in fits in and does not hit the top plates.
Next was to fit the Q-Brain ESC, After many trial fits and mucking about to make sure that it fitted and didnt cover any of the mount holes I was able to get in the space available. I used automotive trim double sided tape to fasten it place. The automotive trim double-sided is thin and super tacky, but can be removed if required.
Q-Brain ESC does fit tightly in the BatBones frame. make for a very tidy power system.
Next was to mount the arms. I used the motor mounts that I got off eBay and the 12mm aluminum tube from the local hardware store. Part of the reason to go for tube as it allowed very easy angling of the rear motor mounts to any desired angle.
One other detail I added was a small brass washer to help spread the tension over a wider foot print on the frame. This was mainly for the folding arm joints but I did it for all through frame bolts.
Frame mocked up ready to work on the rear arm angles. I was not fan of drilling through the frame and securing the rear arms how David did in his V-Tail build. So after tinkering for about 30 minutes I came up with the following solution.
I used the center hole used to mount the rear arm in a tricopter as reference and marked out the center line and about 12mm from the center to mark to new holes. I did this on both the bottom and top plates to increase the changes of getting the holes perfect. I then drilled out a 12mm nylon spacer and used 3mm bolts and washers to create the spacers for the rear arms. If I need to widen the rear arm angles I can do so by inserting something thicker than the nylon spacers.
The final part was to use a zip tie to hold the arms from spreading. This created a very secure and strong rear arm mounting system that has the ability to be adapted if required.
Next I zip-tied a set of helicopter land gear to the frame. This gave it enough clearance for the angled rear blades.
Next I mounted the KK2 and receiver in a clickclack lid. The lid was double sided taped to the frame with a 10mm sandwich of foam from the KK2 shipping case. The KK2 board was also double sided to the inside lid with double sided tape and a 5mm foam layer. The orange receiver was also mounted inside the lid.
Next I created a template out of card to be able to set the rear motor mounts to the correct 40 degree angle. Once the angle was correct the mounts were tighted up.
After get the motors on and doing the basic KK2 config of ACC, Motor layout and other settings it was ready for its for first flight.
Hmmmmm ....... well the first flight was a complete disaster .... multiple crashes and damage.
I called it quits for the night .....
Next day I double checked everything and reset the KK2 board. In my haste of the build I got the rear arm lengths wrong. I had to shorten them by 44mm. Now this time it flew much better, but wow it is completely different beast to a quadcopter in how it behaves. I now understand Davids term of swishy. But not enough to stop from have a few large crashes on its first couple of flights.
Key findings from the first flights :
- Im still a complete novice crap pilot
- The landing gear is not long enough to stop the tail rotors from grounding
- Frame is strong with no damage from crashed
- Plastic motor mounts break
Motor mounts : Turnigy H.A.L. Motor Mount Set(1set)
So the plastic motor mounts held up well to a few hard crashes ... but I didnt want to risk them completely breaking, They were very close to snapping. Luckily I had planned a head and ordered a set of these Turnigy H.A.L. Motor Mount Set(1set). These mounts are designed for 14mm OD tube and I have 12mm OD tube.
Using some 12mm rubber tubing I cut a length 40mm long and cut one side. I then wrapped it over the tube. I then bolted on the HAL motor mount, the rubber filled the gap and also created a rubber isolated motor mount. Not sure what vibration reduction there is as the rubber is high density. But every little bit helps.
The other advantage of using these mounts is that there are screw holes on the side that I was able to use to mount some fibreglass landing gear. I used some of the fiberglass sheet I made .
These prevent the rear rotors from grounding during take off / landings / crashes.
Completed version 2.
But I made a few other adjustments.
The latest change I swapped out the front motors for a couple of RCtimer 1000kv motors I had running 9inch props and added some extra landing protection in the form of foam and plastic practice golf balls.
Here is the Quad family, a KK330 with kk2, a RCtimer 450 with APM2.5+GPS and the new v-Tail. All the builds are detailed on my blog here bluefish.net.nz
One question I do have is that at hover the v-tail is tail heavy, what do I need to correct to fix that ?
I have now changed the rear motors to the same RCTimer 1000kv that were used on the front and also decreased the rear motor mount angle from 40 to 30 degrees. This required a wider distance for the rear booms so I added some wood spacers instead of the nylon one used in the first version. Now if flys great for a novice like me.