A week of improvements (3)

Over the past week, I have continued to fly my tiny whoop religiously. I also have been focusing on upgrading and improving my setup in order to get better performance from both my quad-copter and FPV gear.

The first improvements I made where in software. One of the reasons I chose to use the F3 EVO flight controller on my drone instead of a cheaper, simpler one was because of its programmable and customization nature. As such, I plugged it into the computer and made a few tweaks.

The first thing I did was add EXPO or exponential control to my throttle, roll, and pitch response. EXPO changes the aircraft response curve from a straight line (linear) to an S-curve, flatter in the middle (less sensitive) and steeper at the extremes. This means you get more precise control in the range around neutral where most flying takes place, while allowing for full throw (!) when the sticks are at their extremes. You can see the result bellow.

The second thing I did was increase the rates to the vehicle response. In a non-technical sense, rates controls the rate of rotation on each axis. Say I have the pitch and roll rate at .30, the copter will do flips and rolls at about 360* of rotation per second (or one full flip / roll per second) when the stick is held hard over. If you raise the rates to say .60 the copter will now to 2 full flips / rolls (720*) per second with the stick hard over. I used the CLI command line to change the rates on the quad and make it much more responsive (read: faster) in pitch, roll, and yaw.

I also made a pretty significant hardware change as well. I (along with almost all quad pilots) use Lithium Polymer (LiPo) batteries to power my machine. LiPo batteries have a huge advantage over traditional lead-acid or nickel–metal hydride batteries due to their high max voltage of 3.7v per cell for nominal discharge while still maintaining a low weight. Recently however, Lithium iron (LiFe) batteries have come to be available to pilots. They provide a powerful 3.9v per cell nominal voltage at the same weight. This means more power for maneuvers and punch-outs!

Take a look at the voltage of a LiPO battery (yellow and blue) vs that of a LiFe battery (purple) when discharged at 30 amps.

It is clear that the LiFe battery is able to provide a higher discharge rate and voltage for a much longer time than the standard LiPo battery with the same C-raiting.

I have taken the plunge and bought 5 additional batteries, all LiFe and will be receiving them soon for even more power.

Finaly, I changed the lens on my FPV camera from a wide view raceband lens to a narrow focus unify pro lens. You can see the difference bellow and it is quite an improvement. (this picture is not mine but it shows what the 2 lenses look like on a similar camera to the one I use)