This is an interesting build because it did not turn out as planned. In the middle of this build I have been testing and idea of prop placement within the ducts and it turns out that it can make a difference. If the props are too high, you will some efficiency. Even though we are using mini ducts, they can make a difference in the amount of thrust you get. I will come back to this idea later, but in the meantime, I will take about the problem I encountered.

A while back, I bought some 1507 2800kv motors that was on a 3” quad, but never really pay much attention to them because I did not run 6s. Finally, I have a build that it would work perfectly with those motors. After building the Squirt, I notice that one of the shaft was bent when I was testing the motor direction in Betaflight. It has been so long since I bought it so, I cannot go back to the seller and complain about it. What should I do now, because I need some motors? Since I like trying new things, I came up with another test that I have not tired before. How would a Squirt do with 2004 T Mount motors? I know of 3 props that would work with this setup:

• HQ Duct T75MMX5 CineWhoop 5-Blade Propeller
• Gemfan D76 Ducted 5-Blade 76mm CineWhoop Propeller
• T-Motor T76 3" Ducted Propeller

Of the 3 props I only have the HQ and Gemfan. I just ordered a set of the T-Motor props but that would not show up until the end of the week. If I had to guess, I think the T-motor props would be the most efficient, the HQ will be the smoothest and the Gemfan is amp hungry powerhouse.

I was kind of worried about the HQ props not having enough thrust, but I was wrong. I can hover with a Full GoPro 7 around 20 - 30% throttle. It is kind of difficult to know the actual throttle position because the OSD no longer shows us with the DJI HD system.

3D Printed Parts

In the recent weeks I have been doing a lot of testing with the variouse duct setup and 3D printing settings.

To sacrafice ridgidty I was able to save a lot of weight. I am not sure what is the typical weight for a set of ducts, but in the past I was happy with the 52g weight for the pair. But now, I am able to get a pair of duct down to 32g!

More info coming soon.....

Betaflight

I tried using the Presets on EMU 0.4.0 and it was bad, then I tried 2 other Betaflight tunes for the Squirt and they were also no good. It is rare to find this quad with a T Mount motors so I end up try the PIDs that was on a CineLog 35 because they have similar motor size and surprisingly, it worked very well.
PIDS

set p_pitch = 80
set i_pitch = 88
set d_pitch = 45
set f_pitch = 105
set p_roll = 82
set i_roll = 88
set d_roll = 45
set f_roll = 99
set p_yaw = 80
set i_yaw = 60
set d_yaw = 0
set f_yaw = 99

Rates

As for the rate, I used the same thing I have on the Squirt with 2205 motors.

Filters

set dyn_notch_width_percent = 0
set dyn_notch_q = 120
set dyn_notch_min_hz = 150
set dyn_notch_max_hz = 600

Videos

Fast Flying

GoPro 7 - HQ T75MMX5 - CNHL MiniStar 1000MAH 22.2V 6S 100C Lipo Battery

Same video as above but with the DVR

Madien Flight

Maiden Flight - GoPro 7 - HQ T75MMX5 - CNHL MiniStar 1000MAH 22.2V 6S 100C Lipo Battery

Same video as above but with the DJI DVR