Here's my review of the SCX, actual article
here.
As one would expect from such a small and compact frame it is primarily designed for racing. We at Drone Insider were kindly sent a pre-production model by Chris Armattan to review, and here is what we think:
The frame is available to purchase in Red or Cobalt from Armattan Productions.
First Impressions:
The first part of the frame that struck us was the beautiful red carbon. We feel it’s great to see companies experiment with different colours for the carbon over the boring black. It is likley Armattan will stock a blue/black and a red/black version. We love the red as it matches Emax Red bottoms or the XNovas.
The quality of the carbon seemed good as well. Very clean cuts even around the screw holes for the arms. When we ran our finger on the edge of the carbon there was no dust left over, a sign that the frame has been properly prepped before it was shipped.
The top plate, bottom plate and camera mounting brackets were all very close to their advertised width. However, the arms were not quite at 4.00mm, this may be due to the fact that our model was pre production.
Design:
The SCX goes for a very compact central pod, centred around the included PDB. This PDB is specifically designed for the frame, and features spaces for 2 Pololu regulators as well as conveniently placed + and - pads for the ESCs, the VTx and the Camera. However we would have preferred for there to be holes for the pololus to slot into. Currently there are only pads which makes wiring it up a tad more difficult. Despite this we still think the PDB is well designed and fit for purpose, as trying to build around a regular PDB is very difficult indeed.
The camera mount is specifically designed around the 25 x 25mm board camera, such as the HS1177 or the TBS Zero Zero. Fitting any other board camera will be neigh on impossible, and couldn’t potentially weaken the frame if you were to remove the specific mounting bracket. If you stick to the recommended board camera however, it pieces together perfectly. What we recommend doing is boring out the holes on the HS1177 very slightly. Then assemble the camera holder with the camera in place and top placed screwed in. This means the holes that you bore will be perfectly straight, otherwise it’s very easy to make the mount wonky. Also it is strongly recommended to use a HS1177 with the camera connected located at the bottom, otherwise routing the cable will be very difficult.
The VTx mounting is also very interesting, and different from any other frame we have ever seen. The design revolves around passing the SMA of the VTx through 2 pieces of carbon with an O-Ring between them. The Antenna attaches on the other end. As you tighten the antenna it compresses the O-Ring. It is best described here. This design is certainly unique, and we haven’t had the time to test the design completely during the hardest of crashes. However we are confident it will hold up if the case of most crash, and we have crashed it and can confirm it survives.What does concern us if that if you are using an antenna with a coax that is very rigid. The force exerted in a crash could potentially snap the SMA clean off the VTx or the antenna. Or worse, both. This problem is averted with the coax that is not as rigid but still can hold its place in the case of a collision with a race gate or even another quad.
Another stellar piece of design is the buttressing of the arms. We first saw this on the ImpulseRC Alien and we have also seen it on some frames since then. It significantly reduces stress on individual arms in crashes, by dissipating the energy amongst the other arms. Meaning you are less likely to break an arm in a hard crash.
The Frame is also a “true X” in the sense that it’s shaped like an X as well as the motors are equally spaced.
Another very new feature is the ‘sunk-in’ nuts on the bottom plate. These are just nuts that have been imbedded in the carbon fibre (probably friction fit). Apart from the fact that this could result in the losing the nuts (very unlikely) or potentially weakening the carbon fibre, it’s one less part to drop on the floor whilst building and has saved our bacon multiple times already!
The Build:
When the frame was sent to us the PDB was not yet ready, so our frame contained a 2mm plate instead. This made our build significantly harder as we had to fit all our components in a 30mm vertical stack, and we are not going to lie it was a very difficult build. The hardest part was ensuring that all the wires were of perfect length as there is no room for complacency in this build, if a wire is too long it will get cut. We would rate it harder than a Shrieker, but not quite as hard as a RotorX Atom to build. That being said the included PDB will make the build MUCH easier, as it gives you an extra 8mm margin to work with. Using anything other than a depinned X4R-SB/D4R or XSR would probably be impossible. One thing we do recommend is to put the battery strap in before you put the Flight Controller in, otherwise you will have to thread the battery strap through which is a bit of a pain to do.
Motors: Emax RS2205 2300kv “Red Bottoms”
ESC: DYS XM30A
FC: XRacer F303
Receiver: FrSky XSR
Antenna: A slightly broken ImmersionRC Spironet.
VTx: TS5823S
Props: DAL T5045 V2 Tri Blade
And damn does this build look good, the red bottoms really go well with the red carbon, as do the DAL V2s.
Our build was quite heavy at 343g without battery. We used the ‘cases’ provided with the XM30A to protect the ESCs from damage, which added at least 10g in total. With the included PDB, it should be possible to shave off around 40g if you build tight. Which places this quad well within a suitable weight for racing.
Flight Performance
The inflight characteristics are crisp and smooth. After we loaded up Betaflight 2.7.1, we only had to tweak the P and I gains slightly before we had the quad flying as we wanted. The centralised mass really makes a difference in hard manoeuvres, and we felt that it meant we could let the D gains be slightly lower without getting any bounceback. The VTx mounting solution really does work well in practice, and we have yet to see any issues with the antenna slipping down. We find a good trick is the heatshrink the SMA and the antenna together, so that the SMA is not free to rotate unless the antenna does as well. This completely eliminates the possibility of the antenna ‘sliding’ down into the props.
Conclusion
A well though-out design with quality machining from Armattan. It flies, as you would expect, like a dream and the VTx mounting is innovative, but does work very well. Perhaps its tight build and lack of holes for a pololu regulator bring it down 1 point. At $70 the SCX is on the same level as the shrike, however with the strench of both the frame and the design philosophy, we would argue that it is more than a match for the Shrike.
Flying: 9/10
Build: 6/10
Price: 8/10
Overall: 9/10
