Nano Goblin

Introduction:

Time to see how the scratch built goblins compare with the real thing.

Components:

Nano Goblin frame
TBS crossfire nano receiver
Noxe F4 flight controller
Vivafpv 600mw vtx
Runcam micro camera
2x PowerHD DSM44 6g servo
~~SZ speed 1408 motor with 4" props~~ Emax 1606 4000kv with 3" props
Turnigy AE20a esc
Buzzer
Beitian 220 GPS

Conclusion:

167g dry. I wanted to use a larger motor, but motor mount screw holes are made for smaller motors. The CG was also a factor. I'm going to fly this as is to see what the efficiency is before switching.

Update 4/18/21: Maidened it on a nice day with winds in the 5-10mph range. It flies a lot better on 3s than 2s. I ended up liking flying it on manual mode the most. On 2s, it cruises around 20-25% throttle and on 3s, it cruises at a little over 10% with a max speed of around 90kph (similar to ar6 on 3s). Roll rate is fast and snappy as expected. Overall, it's a good plane, but with the smaller motor, it doesn't quite have as much power and exhibits micro stalls at lower speeds when trying to pull loops (which are not as evident on my custom planks of a similar size using 2204 motors instead. So far, I am preferring my own custom planks over the official nano goblin mainly because it tends to be tail heavy and it is hard to balance it on 2s with a larger motor in the back. I really think it would do better with a 2204 & 5" props instead.

Update 4/19/21: Flew it today at the fore river, which is completely new to me. I have to say that this is quite a bit more efficient than the planks I make by hand. Basically, I found a thermal and this one just went straight up with no effort and I was pretty much gliding and climbing with absolutely no effort. I went to about 400m and had to put the nose down for it to descend again. I later tried the same spot again with my own scratch built planks and they did not perform as well. However, while the official strix version is more efficient, I still prefer my own custom planks for just the way they fly.

Also, after the flight, I realized that the ESC was running a bit warm and even though it wasn't a hot day, there just isn't enough airflow inside the fuse. Therefore, I cut a hole on the side of the fuse and mounted the ESC externally for better cooling.

Update 5/20/21: I had an issue with this earlier on where I would try to do an autolaunch, but it would take off and not know that I had launched so you would have no control of your plane unless you cut throttle and roll to cancel autolaunch. I was finally able to figure out that the way to prevent this is to set the idle throttle much lower so that it won't take off prematurely. This is definitely a bug which inav can fix.

Update 7/15/21: Swapped motors to the stock Emax 1606 4000kv to compare efficiency.

Flight efficiency logs (1408 motor):

15.7km (965mah used)| 3s lion | 61.46mah/km
15.6km (1233mah used) | 3s lion | 79mah/km | Flew 1169 meters high
15.8km (1191mah used) | 3s lion | 75.3mah/km
10.58km (888mah used) | 2s lion | 83.98mah/km
15.86km (1150mah used) | 3s lion | 72.50mah/km
13.1km (1180mah used) | 3s lion | 90.07mah/km | gliding in windy conditions
10.35km (954mah used) | 2s lion | 92.17mah/km | gliding in windy conditions
16.72km (1423mah used) | 3s lion | 85.1 mah/km | Used HQ 4x3x3 prop
15.72km (1375mah used) | 3s lion | 87.46 mah/km | Used HQ 4x3x3 prop
10.19km (869mah used) | 2s lion | 85.27 mah/km | Used HQ 4x3x3 prop
15.46km (1273mah used) | 3s lion | 82.34 mah/km | Used 3x3 prop with higher cruise throttle
16.3km (1177mah used) | 3s lion | 72.2 mah/km | Used 3x3 prop but with lower cruise throttle
16.22km (1311mah used) | 3s lion | 80.82 mah/km | 3x3 prop
13.9km (1109mah used) | 3s lion | 79.78 mah/km | 3x3 prop
14.53 (1213mah used) | 3s lion | 83.48 mah/km | proximity flying with 3x3 prop

Flight efficiency logs (1606 motor):

14.57km (1425mah used) | 3s lion | 97.80mah/km | proximity flying
16.95km (1244mah used) | 3s lion | 73.39mah/km | efficient cruising