[biggestRCEfan]

Inspect the tips of your antennas. I had a similar configuration and in descent the uptown pushed the antennas into the prop. Maybe something else.

[biggestRCEfan]

Kevin, I note that you think that prop below the frame is more efficient. It would be good to have scientific measurements that support this assumption. A prop above the frame loses efficiency due to the blockage effect of the structure below it. A prop below the frame looses efficiency due to “dirty” air flowing into the prop.

The latter is evident in wings where the pusher is noisy (and less efficient) due to the fuselage boundary layer flowing into the prop. This will be less pronounced on a multirotors prop but same principle holds.

Distance between prop and frame is a parameter that may affect efficiency differently in both cases?

The need for clean air entering the proppelor plane is also evident in ducted prop designs, where the design of the lip of the duct needs to minimise stall (and therefore dirty/turbulent air entering the prop plane). But you know all about this :-). Nice work on your ducted props!

[biggestRCEfan]

Mate, that behaviour is normal. When you arm, the FC is driving the position of the servo as a function of a few things. For starters the initial angle when yaw stick is centred reflects the FC knowing that a tilt is required to balance the torque of the third prop (the front two cancel each other).

The movement of the servo when you change the yaw stick position is also the sum of a few inputs, where the stick is one. Anyway, the behaviour is not representative of in-flight behaviour as the craft is moving freely.

Next step is to fly it!

[biggestRCEfan]

Sorry to hear that, Daniel. Did you find it? I lost my V4 on the weekend as well, flying FPV at the beach. My fault as I lost video signal due to flying behind obstacles. For a moment I thought it fell into the sea, but then realised I was heading for the dunes when it happened. Using the goggles we were able to find it. No damage whatsoever due to impact on soft sand and growth.

Did you have failsafe set on the flight control board?

[biggestRCEfan]

Nice. You have a nice area to fly! What camera and settings are you using? GoPro. The image is good.

I decided to go to 3-bladed props to increase the frequency and see if that improves things. Hence the smaller props. Somehow I don’t have the whole as much anymore. From memory I think the PIDs made the difference. Will see how we go when I start playing with them again.

[biggestRCEfan]

Update: I fitted the V4 with 6x4x3 props (not the 6x3x3 I stated earlier). I think it improves the quality of the HD footage.

Here is some footage: https://youtu.be/76wTnOVyPzQ

Wynn, I haven’t changed any PIDs as yet (see my settings above in an earlier post in this thread). But clearly the performance and handling is not good enough. On a 2200mAh 4S I get around 8 minutes, the hover throttle position is about 75%, and response is sluggish. I should increase rates to address this. Current draw in the hover is around 14 Amps (can’t recall what is is with the 8×5 props) and motors and ESCs are handling it well.

Next step is to fit 7×3.5×3 props I have on order, which hopefully would be closer in thrust to the 8×5 props at similar power settings.

Once I am happy with the performance and overall handling, I will start working on rates and PIDs. I believe the image quality can further improve with tightening the PIDs loop gains.

[biggestRCEfan]

Just an update by way of a video flying my V4. There is minor jello which I am going to try to get rid of by using 6x3x3 props. Will see if that helps. But I am quite happy with what I have in the V4 as a chase drone/cruiser.

Check out the https://youtu.be/TgEGRPBI7eU. [Where did the link button go?]

[biggestRCEfan]

Tail tune requires stable hover. This can be achieved by flying with no wind or slight, steady breeze. For steady hover you also need your stick/RC rates set low enough so that minor adjustments to counter any drift dont result in you struggling to maintain the hover because of overreaction due to too sensitive controls. Mainly in pitch and roll. It also helps to have throttle expo set up such that responses in the vertical axis is less sensitive around the hover power setting.

If the above is achieved, the other things don’t matter, as even in acro mode the copter should be quite steady. In fact, I prefer acro, as angle mode tend to drift until you have adjusted the drift out. Airmode does not affect tail tune at all, as it only affects control at zero throttle.

[biggestRCEfan]

Have fun!

[biggestRCEfan]

Mboarman, the tilt to the right shen arming is not a problem. You should be able to take it into a stable hover now. I guess the firmware is setting the tilt angle to an approximate value required to compensate the torque imbalance coming from the rear motor. In hover you will see you that the motor is tilted at an angle.

[biggestRCEfan]

Interesting idea. I found going from 3S to 4S gave me enough step-up in terms of responsiveness and speed. Since then I progressed flying FPV so maybe 6S would be interesting if you want to race.

Did you check if the targeted 6S will fit?

[biggestRCEfan]

James, you landed in a good spot for the tricopters variant of multirotors, or drones in the popular parlance.

I found a few good spots. Google Joshua Bardwell and painless 360 for starters. Both have a wide range of instructional videos and tips wllell organised in themes, that will help you get started. And my favourite: flitetest.

Be prepared though to be overwhelmed by the enormous choice of equipment/components available and by the rate of change. In hardware and software.

I recommend picking a kit where everything is pre-selected to limit the decisions required and build the first one this way. Once you have this flying your will either be hooked or ready to move on to a next challenge …

Think also on the purpose: aerial photography/cinematography, racing, free-style? This will determine some of your choices.

Enjoy! And keep us posted.

[biggestRCEfan]

Kevin, the oscillations I see in your video I wouldn’t characterise as tail wag but rather some oscillations in pitch and roll at the end of a maneuver. What I see is PIDs that need some tuning. Both in roll and pitch the response is not very crisp which leads me to think that roll and pitch PIDs require some work. Did you retain the tune from the previous version of triflight?

What I also found useful in triflight based on BF is to beef up the hyper expo (is this the right term?) on roll and pitch to increase rates when doing flips and rolls. This reduces the time being upside down and less height loss. In forward flight I do a snap roll at full stick deflection without loosing much altitude.

[biggestRCEfan]

Yes Wynn, sorry I forgot that I did a similar research and found the enclosed SD card to be good for the logging application. The 1/2 sampling is working for me, removing those data drops.

Attachments:

1. 

   IMG_20171007_165223.jpg
   

[biggestRCEfan]

Repeat post: previous doesn’t show:

Wynn, The parameters I have set up in betaflight related to this are:

# get black
blackbox_rate_num = 1
Allowed range: 1 – 32

blackbox_rate_denom = 1
Allowed range: 1 – 32

blackbox_device = SERIAL
Allowed values: SERIAL, SPIFLASH, SDCARD

blackbox_on_motor_test = OFF
Allowed values: OFF, ON

I should increase _denom to 2 (I think) as I have a similar issue but not as bad. The result as I understand it will be that the sample rate is multiplied by blackbox_rate_num/blackbox_rate_denom, which will be half the sample/log rate. On the bottom status line of the enclosed image it shows Sample rate = 1/1, After this change it should show 1/2.

My blackbox config file is:

250000,26,3,0,1,1,0
baud,escape,esc#,mode,verb,echo,ignoreRX

Attachments:

1. 

   Screenshot-2017-10-07-07.13.25-1.png
   

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