The HobbyKing SK450 Deadcat Quadcopter is one of the most used search terms when visitors come to Red20RC so I thought it was high time I revisited this neat multirotor frame.
Revisiting and old friend
I’d actually come back to the SK450 a while ago when I tried to fit it with an HK Pilot APM 2.5.2 flight controller. Despite recent versions of Arducopter having the “Spider” as a selectable frame type, I just couldn’t get it to work and got the arse with it once again. I since discovered that my mis-management of the settings on the Taranis meant I was trying to fly with the same elevon mixing I was using on my FPV wing – no wonder it kept tipping up every time I tried to turn!
The flight controller was then relocated to the Q450 Quadcopter project and it was another couple of months before I looked at the frame once again.
The original build had been a little haphazard and messy. I wasn’t too happy with the way the battery sat as that tray at the back is too small for anything larger than a 2200mah lipo, and a frame of this size deserves something a little more for serious FPV use.
I pulled it apart and redid the power distribution board to make all the connections more secure. I also reinstated the flight control mounting plate and located the KK2.1 board as close to the center of the frame as I could.
The battery I moved to a more central position, slung underneath the frame. This gave me room for anything up to my largest 5000mah 3-cells to sit comfortably out in the open.
In total, the changes were minimal but it helped to make the frame look a little cleaner and certainly a lot more functional.
Airborne once again
I retained much of the original tuning that is described in the first SK450 article, tweaking the PIDs slightly here and there to get it more locked in than before.
As usual the test flights were conducted out behind the house with rather suprising results…
So, that didn’t go quite as I had hoped.
Apart from the grey hair caused by nearly losing a GoPro the damage was nothing more than a couple of props so it wasn’t long before I was back out flying – this time at a much nicer venue.
SK450 Dudley Beach
Dudley Beach is an un-patrolled stretch of loveliness on the NSW Hunter Coast. Completely walled in by high slopes and cliffs it offers a fantastic opportunity for some coastal FPV flying and after a night of heavy rain I was presented with nearly perfect flying conditions.
I didn’t get to fly as much as I had hoped as I got sand in my transmitter gimbals and control wasn’t as smooth as it could have been.
TOP TIP! When flying from sand take something to use as a take-off pad and place the multirotor away from or behind where you are sitting. The propwash kicks up a lot of sand on takeoff and it gets EVERYWHERE!
As you can see from the video, I still have a little bit of jello. The camera mount on this frame has no vibration isolation and despite my best efforts to balance everything it shows in the footage.
I really don’t know about this frame. I love the way it looks and I am a huge fan of the Spider/Deadcat layout as it gives you so much more room for gear as well as a clear field of view for filming. My biggest concerns with the SK450 are the arms. Anyone who has owned one will know what I mean. The arms on this frame are considerably thinner and less “braced” than the similar arms found on frames like the DJI F450 “Flamewheel” and Turnigy Q450. As a result they have a lot of flex in them – even the weight of the frame is enough to cause them to bend when sat on the workbench. This can’t translate well to flying performance, espescially as it will amplify any vibration no matter how small.
I’m also beginning to see the limitations of the KK2.1 as a flight controller. I can almost hear the sharp intake of breath at that statement but I stand by it. The KK2.1 is a fantastic board for prototyping, DIY’ing and when you need something cheap and easy to setup for a “throw-away” frame. When you are looking for the ultimate in locked-in, stable, feature-rich performance though it simply can’t compete with the more modern flight controllers and autopilots.
I love my SK450 and it is a shame I’ll probably not fly it again any time soon. It has however provided inspiration to try bigger and better things and has provided a great starting point for my next big multirotor project…