Review: CL Racing F7 Flight Controller

CL Racing F7 FC is finally here! I have been a great fan of the F4 so I cannot wait to check out their latest offering. The F7 maintains the same killer layout, and introduces a few pioneering features which we will go over in the review.

Update Sep 2019: CLRacing released the V2 of this FC.

Learn more about mini quad flight controller in this article.

What’s Special About the CL Racing F7?

I just received the board, so I can’t comment on how reliable this FC is yet. But so far it’s been nothing but pure joy to build. The CL Racing F7 probably has one of the most logical and practical soldering pad layout I’ve seen!

Camera power, signal and control connections are at the front, while VTX connections are at the rear with jumpers to choose input voltage for the camera and VTX. All the pads are on the edge so there is no wires overlapping each other which often creates a huge mess that looks like a bowl of spaghetti.

This board is designed to be used with 4in1 ESC, so there is no integrated PDB. But you can also use it with separate ESC’s by using a dedicated PDB.

Where To Buy?

In the package you will find a cable for connecting 4in1 ESC, extra connector headers to match different 4in1 ESCs, and spare rubber grommets for soft mounting.

Beware that it doesn’t come with any standoff or nylon hardware, so make sure to get your own.

CL Racing F7 Specifications

Here are the basic spec of the CLRacing F7:

  • STM32 F722 MCU
  • ICM20602 Gyro – Up to 32KHz Sampling Rate
  • BEC: [email protected], [email protected]
  • 2S – 8S Direct LiPo Input (up to 36V)
  • 1Gbit Flash Memory for Blackbox
  • VTX Pitmode built into to the FC
  • 6 UART’s
  • Reversed polarity protection
  • 5 Motor Outputs
  • Built-in Camera Control for OSD Pin

There are some pioneering features in this flight controller. Well I am not sure if others have done it before but this is certainly the first time I heard about them in a flight controller.

1Gbit Flash Memory?!

I personally prefer using flash memory for Blackbox, because it’s more convenient to use and doesn’t require an SD card. They also take up less physical space compared to micro SD card readers, and reduce the overall thickness of the board. But the 16MB flash chips on existing FC just aren’t quite large enough…

Introducing the 1Gbit memory chip on the CL Racing F7 flight controller, which is equivalent to 128MB, should be plenty for Blackbox log. Assuming if you log at 4K for 4 minutes each flight, 128MB should be adequate for 15+ flights.

FC Pitmode

Pitmode is basically a feature to turn down VTX power near zero when you are not flying, in order to minimize interference to other pilots.

Now the CL Racing F7 has this feature built into it, it allows you to turn your VTX on or off using a switch on the radio whenever you want.

Direct Solder Buzzer

I don’t know if it’s intentional, they leave just enough spacing between the beeper solder pads, so you can solder the buzzer on the FC directly without the need for extension wires.

Of course this is only possible if your frame has the space, but it’s such a nice touch!

Camera Control

By connecting CAMC pin on the FC to the OSD pin on your FPV camera, you can adjust your camera settings using your sticks! This was a pretty complicated thing to setup in the past, I am glad that CL Racing has it integrated.

I didn’t have to do any of the configuration, I simply soldered the OSD pin from my Runcam Eagle 2 to the FC and it just works!

Closer Look at the CLRacing F7 FC

Loving the layout, it’s so clean! The FC comes with the iconic yellow rubber grommets for soft mounting.

The pins are available on both sides of the board, which makes it flexible for soldering and wiring. The 1Gb flash memory chip is located on the bottom right, and is noticeably bigger than the 16MB ones.

The build quality appears to be top notch.

Building and Wiring

Make sure to check out the manual if you are building the CL Racing F7.

When connecting it to a 4in1 ESC, double check… no… triple check the wire orders! Even better, check each wire with a multimeter to avoid burning your FC.

When connecting Frsky SBUS and Smartport, don’t worry about inversion, any UART will work just fine. That’s the beauty of F7 compared to F4 :)

Here is the official wiring diagram provided by CL Racing. Note that there is a mistake, they had TX1 and RX1 the other way round. Just follow the print screen on your board and you should be fine.

Noise Problem with ICM Gyro?

ICM series gyros was known to have noise issue, and everyone suggests using MPU6000 gyro for this reason. So why did CL Racing go with this seemingly “bad choice”?

Well, it turns out the noise problem associated with ICM gyro’s in the past was caused by poor hardware design – bad power supply to the gyro without proper decoupling.

CL Racing reassured me that they’ve eliminated this noise issue. I will report back once I have tested it.

Flash Memory Not Supported Yet

The 128MB memory chip isn’t working yet in the current Betaflight release (BF 3.5.2). I have been informed that the support for this flash chip is only likely to be merged into Betaflight from version 4.0.

If you can’t wait, you can flash your board with their own compiled BF firmware, download here.

Having Some Power Issue with Pitmode

Unfortunately I had some problem with FC Pitmode. Since both of my FPV camera and VTX are powered by 5V from the FC, I think they must be putting some stress on the 5V BEC. Every time I flip the Pitmode switch to try to turn on the VTX, it causes the FC to restart and so the VTX fails to turn on.

After talking to CL Racing, they reckon the VTX makes a current surge when turning on, and causes the 5V rail to drop below a threshold.

As an attempt to “fix” it, I soldered a capacitor (470uF) to the 5V pad and it worked! CL Racing is also looking to upgrade the 5V BEC from 1.5A to 3A in future revision.

It could be a VTX specific issue (I am using the OBVTX). If you have a different VTX, or you are powering the VTX from LiPo, you shouldn’t have this problem.

First Flight

I love how this FC performs! There is no oscillations at all even running 16K/32K looptime. All seem good apart form a tiny bit of lines when doing punch-outs, not a big deal. I might have to add a low ESR capacitor to the ESC power at some point to mitigate this issue.

21 thoughts on “Review: CL Racing F7 Flight Controller

  1. Matt

    Hi
    I bought this flight controller and wired it up to a tmotor f45 4 in 1 ESC. I checked the wiring pinout vs the esc’s pinout and of course it was completely backwards so I pulled the wires from the plug and swapped accordingly. When I plug in my battery the esc’s make the initial startup tone minus the last 2 beeps. Letting me know it isn’t see the flight controller. And the flight controller doesn’t power on. The wires from the ESC have 16.8v when tested with a volt meter. So it should come on. When I plug in the USB the flight controller comes on and the esc makes the startup tone the way it should. So in other words the only way I can get the flight controller to is to plug in the in USB.
    I’m stumped. Any help would be greatly appreciated.
    Thanks.

    Reply
    1. Oscar Post author

      I don’t know this ESC, check the voltage of the wire that powers the FC? Sounds your FC isn’t getting power from the ESC.

      Reply
  2. Dalton

    Hi Oscar,
    I just bought the clracing f7 after reading your review (thank you!) and I’m trying to take advantage of the built in mic on my Runcam Eagle 2pro. I would prefer not to run the audio wire from the camera in front all the way back to the vtx if it can be avoided. Is there a pad on the fc up by the camera where I can connect the audio wire? The pad layout is so convenient it’s making for a very clean build otherwise. Thanks in advance!
    Dalton

    Reply
  3. BarendDS

    Hi Oscar,

    I installed this fc recently and i’ve noticed that it takes much longer for this fc to boot then all my other fc’s have in the past.
    Normally when you apply power you can hear your esc tune almost right away but with this one it takes 15 seconds before it does anything.
    Have you noticed this also or do you know by what it could be caused?

    I haven’t flown it because I broke my receiver (too much force) when installing it, but everything looks fine other then it takes forever to boot.

    Tx in advance.

    Reply
  4. Vince

    Having an issue with a gray screen using CLRacing F7 and Foxeer Predator v2 Mini. Instead of using OSD wire for small controller, I wired it straight to CAMC on F& board and cut the secondary ground off. Was this correct or does the secondary ground (one intended for camera controller) need to be grounded too? I can’t see why it would be. Regardless, I have a gray screen (NO picture), but OSD works. Although, I cannot access camera setting via OSD. Any assistance would be appreciated.

    Reply
    1. Vince

      Solved. Wasn’t getting necessary voltage to my Camera. So far, CLRacing F7 hasn’t done me well. Had to use the 5v pad on back to power XSR receive and VTX. Neither dedicated pads provided the needed voltage (I used correct jumper). I’m still having a problem getting RSSI. Battery voltage is right, but RSSI isn’t. Still working on that issue…

      Reply
  5. Mark

    Any update on ICM gyro noise? Every FC I’ve tried with ICM 20602 has massive noise in 32k mode, and I’ve always suspected it was electrical not mechanical as it’s across the whole frequency spectrum. You’re suggesting that this FC fixed that, which is exciting! Have you been able to verify this?

    Reply
  6. Markus

    Please review Strix binary F10, as it looks like big innovation😃https://www.readymaderc.com/products/details/strix-binary-f10-flight-controller-heliorc

    Reply

Leave a Reply

Your e-mail address will not be published. Required fields are marked *

Are you Robot? *

For prompt technical support, please use our forum IntoFPV.com. I check blog comments weekly.