dolphin

Introduction:

I've had this kit for a long time, so now it's time to compare how it flies to other 800mm class wings.

Components:

  • AtomRC Dolphin kit

  • JHEMCU Wing FC v2

  • Amax 60A 6s ESC

  • Tmotor F80

  • Sunnysky V3 2216 2600kv

  • Crossfire Nano RX

  • Beitian 220T GPS

  • Tramp HV VTX

  • FX799T 200mw vtx

  • Foxeer Falkor micro camera

  • DJI vista Polar

  • Emax ES08MA II Analog Metal Gear Micro Servo x2

Conclusion:

677g dry. Spray painted gloss red was easy, but laminating the fuse was a real pain. I did like how easy it was to wire up the wing FC. I really like the way this wing looks. It's about the same size and weight as the nano drak, so it'll be interesting to see which one I like more.

Update 12/5/21: The maiden went really well except for not having a properly calibrated compass and no RTH. It launched with a football toss and flew great. It was capable of speeds over 150km/hr as well as slow and floaty flight. It cruises at about 15% throttle drawing under 3 amps. Efficiency was amazing. The same motor with the nano drak 28" wings was drawing 10amps at cruise. The only things I need to change are to disable to compass (use GPS instead) and also to mount the antenna externally instead of internally (reception was not great, unfortunately).

Update 12/6/21: The motor mount broke off with a not so perfect landing. It wasn't smooth for sure, but I wouldn't call it a crash either. I replaced it with a 3d printed motor mount instead that seems much more durable. Also, the vtx reception was better with the antenna mounted outside, but it was still not great compared to other planes, so I swapped the vtx & antenna to see if it will improve.

While this is an amazing plane, the only issue I have with it is that the turns are not as smooth as other wings. I'm not sure why, but it seems to rock a bit on turns. At this point, I'm thinking that it is an airframe design issue rather than a bad servo. This is really the only issue keeping it from being my favorite plane of this size so far.

Update 12/9/21: Couldn't get it to launch properly today after the new motor mount was installed. Not sure what went wrong, but it nosed in and cracked the fuse. Subsequent launches didn't fare any better. Need to repair and try again.

Update 12/12/21: Made some battery cables to run 4s2p li-ion and 4s3p lipos. Had to increase launch throttle to 1930 due to the increased weight. Lipos are easier to launch than li-ion due to the higher C ratings. With the 4s2p 21700 li-ions, I comfortably flew for 30km and still landed with around 3.8v per cell, which is pretty impressive since I wasn't trying to be efficient.

I also tried landing on asphalt and the first one pretty much shattered the landing skids. I lined it with goop and will try again to see if it lasts longer.

Update 12/14/21: Goop works a bit better landing on asphalt. Taking off with 4s2p Li-Ion requires quite a bit more launching distance (half a football field before it stabilizes and starts to ascend). I took it out to over 5km away and it flew pretty well. For more aerobatic flying, it becomes much more agile with 2 4s 1500mah lipo (quad) packs in parallel.

Update 1/23/22: Swapped out to a Mach 3 vtx to run 5s. It seems to do well on 5s, but unfortunately, the vtx was experiencing drifting issues. Will need to swap it out for another one to see how it flies.

Update 3/16/22: Swapped out to DJI vista along with a motor upgrade 2216 2600kv. At first, I used a 6x6.5 prop which was very amp hungry and after I swapped to a Gemfan 6045, it was almost a perfect match for the motor. Top speed is probably over 110mph, but I'm not sure what it truly is since it was pulling over 60amps.

Update 3/27/22: The 2216 v3 2600kv sunnysky motor broke. One of the magnets fragmented and got lodged in the bell. I swapped over to the 1400kv with a 8x6 prop. The new combo has a much more linear feel and tops out at around 130kph with 38amps. It has a much lower top speed and doesn't sounds as good in the air. I need to fly it more, but I think I prefer the 2600 kv version.

Update 4/3/22: With the 2216 1400kv motor with 8.6" props and 4s, I was able to cruise at 80kph on 4amps, 120kph on 10amps, and 170kph on 36amps.

Update 4/26/22: I tried it on 6s li-ion and 7x6 props which I ended up liking a lot more. I was able to go quite a bit faster on fewer amps.

Efficiency Logs:

  • 30km (3000mah used) | 4s2p 21700 lion | 100mah/km - regular cruising, not trying to be efficient

  • 25km (2386mah used) | 4s2p 21700 lion | 95.44mah/km - flying 5km away and back

  • 20.85km (1848mah used) | 6s 21700 lion | 88.63mah/km - regular fast cruising

  • 17.6km (1456mah used) | 6s 21700 lion | 82.72mah/km - 10 min flight (65.61 mph avg) 8x6 prop

  • 23.21km (1670mah used | 6s 21700 lion | 71.95mah/km - 15 min flight (57.67 mph avg) 8x6 prop

  • 28.72km (2101mah used | 6s 21700 lion | 73.15mah/km - 19 min flight (56.29mph avg) 7" prop