I tend to get sucked in by the hype too easily so it was with little thought that I chose the Turnigy Talon Tricopter as my first Multirotor…
Love at first sight
I just loved the carbon, the sleek design, the funky arm folding mechanism, the GoPro mounting tray at the front. This was going to be my first, and most awesome multirotor. I was going to load it up with FRV gear and would soon be swooping through the trees like that Swedish chap over at Flite Test/RCExplorer…
I’d done a bit of reading so I knew what I needed to get. For some of the other bits however I just went with the recommended accessories on the Hobbyking listing. It didn’t take long then before a box arrived with the following:
- Turnigy Talon Tricopter frame
- KK2.1 Flight Controller
- NTM Propdrive 2836 1000kv motors x3
- Turnigy Plush 25A ESC x3
- TGY-306G Ultra fast/high torque metal geared servo
- Multistar 9×6 Carbon props CW/CCW x2 pairs
- Some other stuff…
Putting the Turnigy Talon Tricopter together
Putting the thing together was actually a lot of fun! It was a bit like my old Mechano days; all nuts and bolts and slotting stuff together. Sure, some of the fits were a bit tight and it was a real fiddly job doing the spring loaded arm retaining pins, but I was enjoying myself.
The first real test came when I needed to put the supplied metal servo arm onto the servo. This is achieved by way of mounting the metal arm to the plastic servo arm by passing screws through slots in the metal and into the pushrod holes. This is where I had my first grumble:
- The metal horn is made from soft aluminum and doesn’t look like it will take much abuse.
- The slots are too narrow for the supplied screws so some fiddly drilling is required to get them in. This then makes it nearly impossible to get a 100% square fit.
Fitting the actual servo to the frame was not much better as, even though this was the recommended servo, it was impossible to get it through the hole without actually taking the bottom off the servo and reassembling it once in place!
In fact, I also have to add that the supplied pushrods for the tail servo leave a bit to be desired. They are quite flimsy and difficult to fit. One of mine was actually slightly bent and in the process of trying to straighten it I snapped the threaded section off in the linkage – not a happy bunny – hence why you see a modified sleeve in the photo.
I mounted the electronics how I thought they should go and the KK2.1 fitted perfectly onto the frame using the supplied nylon spacers. I put the ESCs out on the arms as I had read this is a good idea for cooling airflow and also moves potential interference away from FPV gear. I even made up a nice little harness to distribute power from a single battery to all three ESCs.
The Futaba RX was mounted at the back of the frame with a funky polymorh bracket made to direct the antennae up and away from all that carbon. The FatShark TX sat nicely between the frame plates with the antennae poking up directly behind the GoPro, which sits on an anti-vibration pad made from an old mouse-mat.
The motors were a perfect fits on the snazzy looking mounting plates although it didn’t make sense that the countersunk holes appeared to be on the wrong side of the plate!
The KK2.1 is a nice looking bit of kit. I downloaded the user manual from HK and soon had it wired up and ready to go. I was still waiting on a USBasp programming card to arrive from eBay but I just had to give it a go. In fact, the first thing I did was remove all the FPV gear. This was my first time with a multirotor after all and there was a bit of an investment strapped to it!
Turns out taking some of the expensive stuff off was a good idea…
20+ years of fixed wing flying does not really prepare you for the totally alien experience that is multirotor flying. I’d put in a few settings from the internet and was flicking and spinning all over the shop. Of course, then I read the bit that said:
On a Tricopter, you might need to set the rudder in the mixer editor to -100…
That sorted out the wild spinning at least. Now I could get airborne and sort of stable but it still wasn’t cool. I had another look at the HK site and found the tuning sheet for the KK2.1; tapped in those numbers and off again. Now it was a lot more stable – up, down, round and round, oops… down a bit hard… what – why doesn’t anything work?
The KK2.1 was dead 🙁
I did some tests and discovered that a not-very-hard-landing had cracked the 5v power rail in the output pins meaning I had nothing. After a bit of head-scratching I worked out that I could restore power by moving the “charged” ESC around to motor 1 (it was on 3) and using some fine wire to restore power to the other pins. I also ditched the “naked” mounting system in favour of the nice foam box the KK2.1 was supplied in and some hot glue.
Upgrades and progress
By this time the USBasp programmer had arrived and I eventually managed to install it on my PC and flashed the KK2.1 with the latest Steveis firmware. WOW – what a difference that made! I had heard the default firmware was “troublesome” but I never believed by that much!
I was starting to have some doubts about the airframe as a whole (more on that later) but I did finally strap on the GoPro for some in-flight filming…
Unfortunately, my overall impression is that the Turnigy Talon Tricopter is not the awesome multirotor I had hoped for. With not more than a handful of flights under my belt I am finding some frustrating problems:
Those lovely carbon booms
They look great, but no matter how much threadlock you use or how tight you turn the bolts the motor mounts are twisted after every landing and need to be straightened. The carbon even appears to be cracking around the tail because of this constant abuse.
On top of this, where the tail boom mounts to the frame is not very strong at all and is constantly coming loose.
That tail servo mechanism
I’d seen comments around that the thrust bearing in the tail was useless but it seemed solid to me during the build. I’ve been forced to change my mind however as I have already bent one screw and the replacement comes loose on every single flight. On top of this the screw head is nearly impossible to reach without removing the whole thing from the boom each time.
This always results in poor flight performance as you can see the vibration in the tail during flight.
Take a look at this video of the damage caused by today’s outing:
NTM Propdrive Motors
Again, further reading shows some poor reviews of these otherwise fine looking motors. I’ve had one that seemed to have a misaligned drive shaft attachment and the others seem to have a lot of slop and vibration in the cans. I’m not convinced these are really the best motors for the job.
Turnigy Plush 25A ESC
This is more of a heads-up than a complaint. I had good intentions of flashing my ESCs with the SimonK firmware but it turns out you can’t do that with these ESCs as they have the SiLabs chip on them. If you want to flash you ESC you need an ATMEL chip unit – apparently.
I went into this project with high hopes for the Turnigy Talon Tricopter but I have to say I am less than impressed. For an experienced multirotor pilot with the time and knowledge to engineer out the problems it looks like it should perform but it just doesn’t do it for me.
I’ve ordered a replacement tail assembly from HK but I’m not sure if I will ever use it. I might just build a different tricopter like David Windestal’s tricopter or maybe even get one imported from Fortis Airframes in the USA. To be honest I’m even returning to my original thoughts of building a deadcat quad or v-tail.
Well that’s blown it! I went out for another fly whilst still writing this article and the Turnigy Talon Tricopter had one hard landing too many.
I was practicing hovering around the reserve behind the house and a sudden strong gust (yes, that bloody wind again) pushed me back into a tree. I only clipped the tail on a branch but that was enough to flip the tail and bring the drone down flat on its back from about 10 feet up. The impact had the effect of shattering the LCD screen on the KK2.1 and stripping the shaft on the tail servo. The frame survived, not so sure about the motors.
So, I’ve decided to put this one on the back burner and have now got a SK450 quad and DC conversion coming along with a new KK2.1 (in fact I already have another in reserve) and some different motors/ESCs.
Watch this space!