Here’s a little insider info into the Propwashed product testing “department”: I’ve been sitting on a Betaflight F7 flight controller from FPVModel since February. Shout out to FPVModel – they sent us this FC for review no questions asked despite a couple of less-than-stellar reviews we’ve written about their products in the past. Unfortunately, it seems like this may be the way that the Betaflight F7 is going — through no fault of FPVModel or the manufacturer of the board.
When this FC was announced I was really excited. I anticipated being able to run Betaflight with everything turned on (Dynamic + BQRCF2 filters with maxed out DSHOT) without any overclocking or performance worries. It comes with the high-performance ICM20608 gyro which can be run at 32kHz. I was really excited to try this out with the Fast Kalman Filter. It also has a secondary MPU6000 which opens up an interesting new avenue for dual-gyro filtering (which I am told the Betaflight devs are looking into for 3.4, by the way).
When I received the FC in the mail back in early February, I immediately gutted my beloved Bolt 210 and stuck in the Betflight F7. I was happy to find out installation was similar to the Betaflight F4 – which I loved. The excitement continued to grow.
It all came apart when it came time to actually flash the flight controller. I had to download Betaflight 3.3 pre-release builds at the time to even get the BETAFLIGHT_F7 target option (which was expected), but those builds simply did not work. The FC would not even connect to Configurator. After perusing the forums and seeing others having similar problems, I shelved the project for a few weeks.
I came back to it in late April, hopeful that the gremlins had disappeared and I could start trying out high-performance Betaflight. This time, I was able to flash a released build and connect to Configurator and set-up my quadcopter. Likewise, I was finally able to take-off! My elation was short-lived as an audible motor twitch was immediately evident. Wondering if I had somehow damaged an ESC capacitor or shorted a motor winding when installing the F7, I landed and did a close inspection of the power system PCBs and wiring. I didn’t find anything.
Looking at the Blackbox logs, I noticed that there were several sections of log that got missed. This is evident in the Blackbox Log Viewer by sections of disjointed graphs:
I’ve seen these in the past, and it generally indicates that the CPU is being overworked in some way – logging is the lowest priority task so it will get cut out before anything else. Suspecting DSHOT due to some things I’ve read on community forums, I tuned ONESHOT125 for the quadcopter and went out to fly again. The quadcopter flew perfectly — and I was very disappointed. So much for being able to test out the latest and greatest, with all features enabled.
So this leads to my conclusion of this subdued article: F7 flight controllers are flyable, but they are still far behind their F3 and F4 brethren. If you think you are going to get the latest in cutting edge performance from an F7 flight controller, think again. That being said — my experience over the last few months has proven that this is all a software problem. Sooner or later someone in the Betaflight development community is going to get their act together and fix whatever problems exist with these FCs (shout-out to developer DieHertz – he has made some of the most substantial F7 improvements in the last few months). I’m really excited to try out (and review) my Betaflight F7 when that happens.