Flight Controller

The flight controller is equivalent to the “brain” of the racing drone. Racing drones’ flight controllers have been evolved from CC3D, NAZE32 to F4 and F7. Simply speaking, the flight controller chip has been upgraded and the processing speed is faster. There are more functional ports and functions are more integrated.

The above is a brief introduction of F1-F4 flight controllers, cited from http: //www.moz8.com/thread-90524-1-1.html.

Instead of being called flight controller, it is now called “stack”. The flight controller, 4-in-1 ESC and older analog image transmission module (relative to DJI HDL FPV transmission system) are piled together. The ports are also compact.

Next, I’d like to introduce several stacks I played before.

MAMBA Both workmanship and price are nice. The drawback is that the board is not coated with conformal coating. At the connection place of cables, the circuit board is a bit bulged, the module may not fit into the frame.

DALRC An aluminum shell is added on the ESC for heat dissipation. It is quite expensive.

HobbyWing This is a mature manufacturer for ESCs. Its ESC is coated with conformal coating, and the price is a bit high. Personally speaking, its stability is good.

Frame

Main frame parameters are shown below:

Wheelbase: This is the distance between the central axes of two diagonal motors. The 5-inch drone means that its propeller is 5-inch. Its wheelbase is about 220mm.

Arm thickness: The mainstream arm thickness is 5-6mm, and the thickness of the upper carbon board and lower carbon board of the airframe is 2-3mm.

The TransTEC frame recommended by the DJI Online Store is compact. The antenna can be fixed by TPU base. During flying, the fragile connector is protected as it is inside the airframe.

Battery

I still remember that in the age of CC3D, 3S battery and tri-blade propeller were used for racing drones. In today’s mainstream FPVs, 4S or 6S batteries are used, with capacity ranging from 500mah to 1,550mah. The “C” value soars from 45C to 120C.

Some basic concepts of battery are described below.

The standard voltage (storage voltage) of lithium polymer battery is 3.7V, and the fully-charged voltage is 4.2V, which can be 4.35V for some high-voltage batteries on the market. If the voltage of a battery cell is lower than 3.3V, it is called over-discharged, resulting in swollen and inflation. At this time, the battery performance is subject to irrevocable damage.

S: The number of cells. 3S means that 3 pieces of cells are connected in series. Standard voltage 3.7×3=11.1V.

mah: This represents the battery capacity. When the single cell is 3.8V, the capacity is 50%. Therefore, when the voltage is 3.8V-4.2V, about half of the nominal capacity can be charged. Based on this, you can estimate whether the capacity is false.

C value: This represents the discharging capacity of battery. For example, in a 1,500 mah battery, 1C discharge current is 1.5A. 100C means 150A discharge current. The higher the C value, the stronger the discharge capacity is, and the more powerful the battery is.

Some reliable battery brands are shown below: Grepow, Dupu, Fullymax and Nanjue. Some special batteries for FPV, such as Snowman are also launched, which will not be evaluated as I haven’t used them. Anyway, Grepow is a good choice.

It should be noted that some FPV batteries (including Grepow R-line batteries) are high-voltage. That means, the single cell voltage after being fully charged is 4.35V. Some chargers such as ISDT can charge these high-voltage batteries. However, if you have an ordinary battery, remember to adjust the charger to 4.20V charging mode. Otherwise, it would be dangerous to charge an ordinary battery to 4.35V.

Battery charger

Usually FPV batteries are small. It is suggested to select small-sized chargers without power adaptor. Therefore you can charge the drones with high power batteries when flying outside. The power doesn’t necessarily need to be too high. The key point is that it’s small sized and easy to use. If the capacity is 1,500mah, use four 2C chargers for charging:

1.5A×2×4×16V=192W.

Based on the calculation, it is enough to use three pieces to charge 150W. Currently, I am using an ISDT SC608 charger, which has been launched for years. The original parallel charger board is of good quality, and the price is acceptable.

The mainstream trends for model airplane chargers are small-sized, high power and convenient. Balance, however, attracts less attention. Based on the service life of 200-300 circles, an ordinary balance charging can meet daily needs. I often use the A6 charger for balance charging after flying. My A6 has been used for seven or eight years and still works well.

Thanks so much for sharing

Hello and good day Freefly-FPV. These information is wonderful. Great information and thank you for sharing.

Nicely done - thanks again for sharing!

Thanks for sharing the information!