nano drak
Introduction:
This was quite time consuming to build. Even creating the stencils from CAD took a bit of trial and error. The front and rear battery hatch are custom since I needed something elevated to be able to use 6s 21700 batteries. The whole thing was then laminated.
Components:
Nano Drak 28" wings w/3d printed parts
Matek F405 Std flight controller (powered by a 5v bec)
Amax 60A 6s ESC
SunnySky 2212-6 2450KV motorBrotherHobby Avenger 2808 1500kv motor w/ 7x5 prop
Crossfire Nano RX
Beitian 220 GPS
Tramp HV VTX
Runcam Swift camera
JX PDI-1181MG servo
Conclusion:
628g dry although I need an extra 12 pennies in the front as ballast.
Update: 10/6/21 - Cooked the motor on the maiden flight. Luckily, I was flying in an empty field and didn't lose it in the water like the other time. I knew I would be at the limit, but felt it was ok since I was using li-on batteries and limited throttle to well under 50%. Cruising throttle was around 12%.
Update: 10/7/21 - Second day of testing was lousy in terms of luck. Couldn't even get her off the ground. Crash after crash during launch. I came home and figured out that I didn't set the degrees properly for autolaunch to work properly for overhead throws. Unfortunately, the F80 motor smoked during one of the failed launches when it hit the ground and continued to try to spin. I quickly disarmed, but for some reason, Inav doesn't recognize disarms quickly when it is in launch mode (wtf??). The only way to immediately cut the motor is to cancel autolaunch by moving the right stick.
I don't want to fry anymore new motors during testing, so I slapped on a really old emax 2212 1400kv motor with lower pitch 6" carbon fiber props.
Update 10/13/21 - Third day of testing was really bad. After another few failed launches, the FC reset itself completely and erased all the settings.
Update 10/14/21 - I swapped the motor to a 2212/2200kv with the recommended 5.5" props and 4s to try to get closer to the stock settings. I figured that a lot of my previous issues were not due to bad throws, but rather to bad motor/prop combos and torque roll/not enough thrust issues. After many more bad autolaunches and broken props and mounts, I was about to pack it in until I decided to try manual launches again. Amazingly, I was able to finally launch it manually two times in a row, but since I broke all the 5.5" props I had with me, I had to switch back to a 6" prop and it fried again. This is now the 3rd motor I burned up during testing. However, I have made progress in launching it. After launching, I realized that all my autolaunches were failing because the gyro was not working properly. My guess is that it had somehow malfunctioned from all the crashes because my artificial horizon was spinning around like a clock whenever I was flying level and when I tried to put it in angle, it would bank sharply. After a few mins of flying though, the issue cleared itself up. Unfortunately, the motor also fried at that time and all my flights ended.
I feel like I'm making progress, but this has been very painful along the way...almost like when I first learned how to fly.
Update 10/15/21 - Swapped in another F80 2200kv with a 5.5x4.5 prop and have had mostly successful manual launches since. I feel like it is underpowered since launches require 100% throttle. It also doesn't feel very powerful at all and looking at the efficiency logs, it looks pretty bleak at around 120mah/km for regular cruising around. I feel like it needs another prop or motor to really wake this wing up.
Update 10/18/21 - Swapped to a 5.5x6.5 prop and could not get it to launch. The FC did a complete reset after a crash and I could not continue until I reloaded my backup config. There was just way too much torque roll.
Update 10/19/21 - Swapped to a 6x3 APC prop and was again successful in launching. In fact, it launches easier than the 5.5x4.5 prop. In the air, it is an improvement over the 5.5x4.5, but still feels lacking. Cruise is about 30% throttle @ 10amps on 4s.
Update 10/21/21 - Swapped to a 6x4 prop and crashed it a couple times trying to hand launch. The torque roll issues were really bad. I later measured and set the autolaunch throttle to 65% and did the overhead launch and it took off easily. All subsequent launch attempts had no issues with the same method. It flew a lot better with the 6x4 gemfan than the 6x3 apc, but I still felt like it could be a lot better if it had more power. I also flew it today with a 4s 21700 li-ion pack. It flew pretty well and I may make more to switch over.
Update 11/2/21 - I tried the 5.5x6.6 props again after getting it flying well. Top speed reaches 150kph now, but overall, I don't like the flight characteristics as much since it loses quite a bit of static thrust.
Update 11/4/21 - Failed on about half of the takeoffs and I have no idea why. On the last failed launch, it hit asphalt and bent the motor bell, broke the motor mount, destroyed both coroplast winglets, broke the camera, and tore off a ground cable from the FC.
Update 12/14/21 - Swapped out to a Xing 3106 motor with 7" props. It flew a lot more efficiently on 4s cruising at around 7amps. Top speed has gone down to 100kph, but the most annoying part is that there is a lot more torque roll can be felt in manual mode. Will need to try it again with 6" props on 6s.
Update 12/16/21 - Tried the Xing 3106 motor on 6s with 6" props and it was amazing. It cruises and generally flies much better at around 7-10 amps on 21700 li-ions. I'm going to try swapping to BH 2808 1500kvs as it seems to be a smaller motor with even better specs on paper.
Update 1/23/21 - Swapped out to the extended wing set. It cruises at just under 4 amps at around 50kph. The ext wings are highly maneuverable and the roll rate is really amazing for a 1 meter wingspan plane. It does fly a bit slower with the advantage of higher efficiency.
Efficiency Logs:
16.66km (1393mah used) | 4s lipo | 83.61mah/km | 6" carbon prop on 2212 1400kv 80% throttle limit
15.37km (1369mah used) | 4s lipo | 89.06mah/km | 6" carbon prop on 2212 1400kv 80% throttle limit
10.5km (1210mah used) | 4s lipo | 115mah/km | 5.5x4.5 prop on F80 2200kv
12.5km (1509mah used) | 4s lipo | 120mah/km | 5.5x4.5 prop on F80 2200kv
13.73km (1702mah used) | 4s lion | 123.96mah/km | 6x4 gemfan prop on F80 2200kv
13.3km (1310mah used) | 4s lion | 98.49/km | 6x4 gemfan prop on 2212 2450kv - steady cruising
13.1km (1676mah used) | 4s lion | 127.9mah/km | 6x4 gemfan prop on 2212 2450kv - more aerobatics
15.5km (1600mah used) | 4s lipo | 103mah/km | 7x4 gemfan prop on 3106 1500kv motor
17.2km (1364mah used) | 6s lion | 79mah/km | 6x4 gemfan prop on 3106 1500kv motor
15.3km (1455mah used) | 6s lion | 95mah/km | 6x4 gemfan prop on 3106 1500kv motor
17.5km (1617mah used) | 6s lion | 92mah/km | 6x4 gemfan prop on 3106 1500kv motor
17.7km (1450mah used) | 6s lion | 81.9mah/km | 6x4 gemfan prop on 3106 1500kv motor