I will be building the Compass Model Atom 500 electric heli over the next week. It comes 80% assembled from the factory, so it shouldn't need more than a few hours but I'm a meticulous (prefer that term to "lazy") builder. The build will be documented here with pictures.

This is the G10 frame version with 60A HobbyWing Platinum ESC included. Two pinions are included in the kit. The 8T one is for beginners who don't need the power needed for 3D flight, but rather would have a longer flight.

Manual, parts list. You can also see the ESC package.

Contents laid out.

Tail fin attachment and screws.

Main gear, auto rotation hub and hardened main shaft.

All bags have a sticker to associate them with the build step in the manual. You only need to open the bag for the step you are on. Do not open all the bags at the same time, it is easy to mix up screws and wonder later what goes where.

Metal tail case. The tail mechanism is a great design with zero slop unlike other helis I have seen.

Metal Head, blade grips, flybar carrier. This beauty will be unwrapped later in the build.

Metal swash plate, flybar paddle and washout assembly.

The links are already assembled  Though they are already sized close to the required length, some adjustments may be needed depending on the servo you use. The ball links are tight, will need to be reamed.

A ball link reamer is included in the kit  That is a nice touch, haven't seen any other manufacturer doing that.

There is already one pinion installed on the motor. This is the second one. The 9T is used for higher performance, but this will use more power and hence flight will be shorter. Unless you are into 3D, use the 8T pinion, this will give you a longer flight. Beginners might also want to remove the spacers in the swash to tame down the heli. Experienced fliers would prefer the crisp response of the stock setup.

Servo horns, link balls etc

G10 frame and motor. It is a hefty motor capable of much more power than needed. Overdesign is good here, I don't like overheating motors, the NdFeB magnets in brushless motors don't like heat much.

Note to myself: Remember to remove the sticker from the motor before the test flight.

All bearing blocks are metal in this heli, absolutely no need to upgrade. The bearing seems to be greased already.

Again stock part is metal, no need to upgrade. Also they have bearings unlike some other helis.

Painted fibreglass canopy. Looks much better than plastic canopies. This one looks great. Frankly I hate the canopy designs on other helis from Compass, they need to hire a better designer.

That's all for today.

These servos and gyro are getting good reviews so thought I'll try them out.

Cyclic: DS510
Tail: DS520
gyro: GP750

The other servo options are Futaba 9650, Inolab HG-D260HB, JR Z3650, MKS DS9660 etc. For the gyro you could use Futaba GY401 on the lower end or spartan DS760 on the other.

Go over the frame with a file lightly to dull the sharp edges of the frame. Otherwise the sharp edges can cut into the wiring over time. You could also use sleeving or fuel tube to protect the wires.

There are two sets of servo horn included in the kit. One for futaba and other for JR. Align servos has the same splines as Futaba, so I'll be using them. These horns are quite a bit beefier than the horns that comes with the servo, no chance of flexing under load. They are a tight fit on to the servo, so there is no slop at all.

There are markings on the horn to identify them as "FU" and "JR" type.

The servos are mounted from inside the frame. I found it easiest to get the servo in through the slots for main gear and then position them.

There are 3 lengths of screws provided for servo installation. The longest one is for use with a standard size tail servo. The middle one is for elevator servo and smallest for the aileron ones.

I used the grommet that came with the servos for the aileron servos. The eyelets are too small for the screws, so I left them out. The manual recommends installation without using them. The mounting holes on the servo is oversized for the screws, so I thought there might be some play if installed without the grommets. However later I was forced to mount the elevator servo without them and it seems to be fixed solidly. Later in the build I'll remove the grommets if that gives me better alignment.

Notice the elevator servo is installed with spacers. This is required to align it with the swash elevator input.

For the tail servo, there are two slots provided on either side of the frame. One is for a standard sized servo and the other for a mini servo. I'm using DS250, so mounted it on the mini servo slot.

The aluminum tubes are a tight fit on the landing gear struts. I decided against reaming them, but soon started regretting it. It is really tight, I'll be reaming it next time I have to do this. This was unlike Knight 3d landing gear which was a breeze to fix. Compass model heli's use ball links as holders for antenna tube. So if you need one for a quick fix at the field, you know where to get one 

I usually dab a bit of epoxy glue on the skid caps. They seem to be nice fit already, but this was something I learned to do with other brands where the skid caps fall off soon and carried over the procedure as extra insurance.

Good going  

BTW, I found that sand paper worked a bit better than a file while trying to remove the sharp edges from CF frame plates.

I didn't have sand paper handy. The needle file worked out really well. But I can see how the rounded corners can be easier done with sand paper.

nice build log