AtomRC Dolphin - Launches on 4S and 6S

Comparing launches of my AtomRC Dolphin
I had three flights on my AtomRC Dolphin before it met an untimely demise due to some kind EdgeTX/IRC Ghost/Horus X10S-slow-inverter-failsafe perfect storm. Initially built with a 2208 1750kv spinning an HQ 7x4.5 on 4S, none of the launches (INAV auto launches) were particularly confidence-inspiring. Though the plane flew well in the air with that power system, I didn't like the sound of the prop trimming the grass as it came within inches of the ground. So after the plane augered into the dirt and needed some repair anyway, I swapped the 2208 motor for a 2807 1300kv and the 4S 2200mAh for a 6S 1500mAh.
The first launch (and flight) on 6S was fantastic. Not a hint of doubt anywhere in the sequence. The prop does sound like it's distorting a bit at full power (HQ 7x5.4 V1S bi-blade), but anything below that and the plane just goes. I'm quite happy with the upgrade.
-- AtomRC Dolphin --
First motor: T-Motor Velox 2208 1750kv / 4S 2200mAh rcbattery.com
New motor: EMAX ECO II 2807 1300kv / 6S 1500mAh CNHL
HQ 7x4.5 V1S
Strix Rocket 65A ESC
Matek F405-WING w/ INAV 6.0-RC3
iFlight M8Q-5883 GPS
EMAX ES09MD servos
DJI Air Unit
FeeTech FT90m pan servo
Insta360 Go 2
ImmersionRC Ghost Atto 2.4Ghz Receiver
-- Ground --
Frsky Horus X10S
DJI Goggles V1 w/ WTFOS
iFlight Crystal antenna, swapped for 5-turn "Death Ray" helical antennas
Two sons running ground support that make every success and failure more fun

[@IanF-FPV]

I like how after the crash video you put your RSSI right in the middle of the screen 😂.

[@GhostRyderFPV]

My maiden throw went exactly like your second throw - wild! My flight: _"Thank you autolaunch thank you autolaunch thank you autolaunch!"_

[@brubakerjm]

Haha! I know the feeling all too well! My first 3D-printed plane maiden was millimeters from disaster but auto-launch squeaked it out! kzbin.info/www/bejne/bGfXe3-jqJiJe7s

[@вечная_мерзлота]

nice work. camera panning ability is awesome.

[@brubakerjm]

Yes! I discovered how awesome panning is last year and nearly every plane I've built since as a pan in the nose! Thanks for watching!

[@SteveJohnstoneNG3D]

Great video, very inspiring, thanks for sharing.

[@smookicz]

I think instead of throwing plane with spinning propeller over, using plane throttle power while holding it from the front and releasing in to air is really just qite easier and safer. Also these launches will reliably turn out qite all the same every time as only wind or changing trust to weight ratio will change them. Just beware that it require different settings, as plane might take off with slower acc without trigering, so the sticks and the timer will not then deactivate launch, so acc trigger needs to be set lower, and as there is little danger from the propeller upon releasing the launch trigger time can be shorted and it can have zero delay and this faster reaction time can be used for more spinup time.

[@dronepilot260rc]

Seems like you need a little upwards thrust on the motor. The way it nose dives initially is either motor thrust angle or too nose heavy

[@brubakerjm]

I was spot-on for factory CG markings, so I don't think it was nose heavy. Could be thrust angle? My 3D-printed motor extension had a very slight curl on the motor face after printing, so maybe that induced a degree or two of misalignment. To counteract that, I would need to shim the bottom of the motor, correct?

[@dronepilot260rc]

@@brubakerjm kzbin.info/www/bejne/aWaropiEjZl7ers. Could also just be the propeller but here my launch on 4s lithium ion pack and it leaves flat on launch with no effort. I have a small amount of up thrust on the motor.

[@opt123123]

@@dronepilot260rc The issue was too much nose up attitude on launch so the flight controller had the ailerons pointing down when you threw it. As soon as you threw it down pitched ailerons pitched the nose down to the set launch angle, but the airspeed was too low (+ downward rotating inertia of the aircraft) for the ailerons to keep the nose at that angle so the nose continued to pitch down until the airspeed increased and pitched the nose up again. Pretty common issue to be aware of and why you dont launch in auto level without pulling back on the stick at the same time.

[@dronepilot260rc]

@@opt123123 I fly without a flight controller so there is no (Auto Launch 🚀) I feel like learner how to launch a plane manually should be a mandatory skill 🫡

[@07onurboyuk]

You are perfect, the flights are great. I am Onur from Turkey. Can you please tell me if there is a camera servo line, I want to buy one too. It is small and rotates all the way to the back.

[@brubakerjm]

The camera is mounted on a Feetech FT90m servo. I extend the servo endpoints in INAV to something like 750 to 2250 PWM and it can turn about 300-degrees. Thanks for watching!

[@Catboy-hr2qp]

Glad i decided to go 6s i was gonna a 2806.5 1350kv on 4s with a 8.4AH pack now planning to use a 6s 10AH pack funny thing is the 10AH pack is over 100g ligher so win win

[@user-otzlixr]

Great videos , but I worry how you have the plane pointed at your face when you arm it.

[@brubakerjm]

Thanks for your concern! I'll try not to get complacent!

[@edygome]

Thats awesome!!

[@brubakerjm]

Thanks for watching!

[@wallaguest1]

what OSD is this one? i like it, you see this OSD live like that or is telemtry added in postproduction? the one of the initial images, thats just on top.

[@brubakerjm]

The KZbin video has the OSD added in post-production, but it looks exactly like that in flight. The DJI Goggles V2 *can't* record the OSD as part of the DVR recording, so one has to use a separate utility to add the info back in during post-production. I'm using FPV.WTF firmware on the Goggles V2 and SneakyFPV fonts for the symbols. So what you're seeing in the video is what I saw during flight, but it has to be re-created in post. This is one of the reasons I like my DJI Goggles 2, since they record the OSD on the DVR, but the fonts are not nearly as good (or as complete) as the FPV.WTF ones. Oh shoot, sorry. You said the one with the info on top. Yes, that is created only in post-production. I record the telemetry on the radio using OpenTX, then import the DVR and OpenTX log into a program called Dashware which generates the overlay, then layer the overlay on top of the DVR and re-render it. There are tutorials on KZbin (search "dashware opentx logs") for doing this that I followed and messed with until I finally got it acceptable. Thanks for watching!

[@GaryBaird.Photography]

Is there a 'return to home' mode on this outfit?

[@brubakerjm]

Yep. The flight controller is running INAV so "return to home" is one of the modes I have configured. Unfortunately, during the loss of RC control, I don't think the FC "saw the failsafe" and didn't attempt to "fly home" until it was buried in the weeds. Other than that incident, RTH works well.

[@Crunklefloop]

1:33 was cutting it close!

[@brubakerjm]

Yeah! "Cutting" a little too close! You can hear it tick the grass. And of course, I get away with a sketchy launch on the same flight that a failsafe ends my fun. :)

[@Crunklefloop]

@@brubakerjmThe foam gods work in mysterious ways!

[@brubakerjm]

@@Crunklefloop What they giveth, they taketh away!

[@romanfomin5653]

Судя по твоим стартам ты реально под Богом ходишь :). Тебе надо мотор поставить 2806 1800 кв с 5 дюймовым пропом.

[@erlandfpv]

Hi, if we using 28xx 1300/1500kv, it would be nice too with 6s1p 21700 liion? Thanks before

[@brubakerjm]

Yes, 21700 would work, probably high amp cells like Molicel P42A. I have a 6S1P 21700 to try in my Dolphin, but it will not balance with the lithium-ion battery in the forward position. I would need to add weight in the rear compartment for it to balance. I plan to try it, but have not had time yet.

[@erlandfpv]

​@brubakerjm thanks for replyng, i have pnp version, but so many friends say it will bot good enough, mine is v1, 2000kv motor, so others say it will burn ASAP, if u know VISMA on youtube, he using f90 tmotor 1500kv with 6s1p molicell, and 80A esc 😄, so in the middle, I'm thinking about 1500 or 1300kv, will it make so much different ? 1500 or 1300kv, and the last, did u have link to motor mount? Thanks before.

[@brubakerjm]

@@erlandfpv I love VISMA's videos! I watch them all. The F90 is an excellent motor to try. I'm not sure how he gets the plane to balance with that 21700 pack. I run EMAX ECO II 2807 1300kv on mine and on 6S it packs plenty of punch and can flatten the HQ 7x4.5 I'm using. I use a 65A ESC. If you go with 1500kv, you could probably switch back and forth between 6S and 4S. Something like 7x4.5x2 for 6S and maybe a 7x6 (or even 8x5) on 4S. This is the motor mount I used: www.thingiverse.com/thing:5147947 I had to cut away some of the internal space so my M3 socket head bolts would fit. If your motor is 16x16 mount, then you probably also want to print one of these: www.thingiverse.com/thing:6056736 I didn't think of that and instead drilled out a normal, aluminum x-mount for 16x16 holes.

[@erlandfpv]

​@brubakerjm thanks for the detail, i appreciate it 🙏, using 6s and 4s sound good with 1500kv then, I'm new to the fixed wing world, daily I'm using heewing t1, but i love dolphin, it runs very quick and have a so mich space on it. , 😁👍👍👍👍

[@Gonzalo-qf6ov]

I don't appreciate iNav launch logic actually, motor go full power in air still gives great amount of torque. Either iNav or AP should achieve sufficient RPM for launch ON THE GROUND before airborne.

[@brubakerjm]

The "idle throttle before launch throttle" is adjustable in INAV, and some people do indeed set 100% throttle so there is no "ramp up" after the throw. For this model, I wouldn't be comfortable with that much thrust in my hands, so I am still in search of the "perfect" settings, which probably don't exist as different models can be quite unique. I should note that I have *not* done the "hover test" and found the amount of throttle I should actually be setting the launch throttle to as suggested by INAV people.

[@Gonzalo-qf6ov]

@@brubakerjmJust go 97% on 6s, nose up and back toss to your behind.

[@nlexfpv]

hi how do u fitted 2807 1300 into dolpin..any 3dprint part? if u do may u share it pls

[@brubakerjm]

It was a little difficult. I am using a 3D-printed extended motor mount. Then a normal, metal x-adapter drilled out to fit the 16x16 mounting pattern of the 2807. Then getting the screws past the motor bell required putting the outside screws through the x-mount first, then attaching the motor, then attaching the x-mount to the plane. If I was doing it again, I'd 3D-print an x-mount that already had 16x16 holes, and would probably add a 10mm spacer between the motor and x-mount to make getting the screws in easier. Here's the mount: www.thingiverse.com/thing:5147947

[@brubakerjm]

Here's a few more links to check that I came across when working on it. One solution: www.rcgroups.com/forums/showpost.php?p=50582963&postcount=1964, another solution: www.rcgroups.com/forums/showpost.php?p=50587347&postcount=1970, and a different swappable mount I couldn't use because my mount was already glued in: www.printables.com/model/402023-quick-change-dolphin-motor-mount/files

[@EnglishTurbines]

If your going to use 2.4g ELRS for control, then CROSSFIRE protocol gives you Link Quality and also a live indicator of RF assuming you're using auto RF ramping. Paints a better picture of your control link IMO......🤔😮😏😏😏🇬🇧

[@brubakerjm]

This particular plane uses Ghost for control, so the CRSF link stats aren't available. On my other ELRS planes, I typically just show LQ in the OSD unless I have plans to fly in such a way that the link might be close to failure. I have tried dynamic power on ELRS, but I don't really like it, to be honest. It's just another variable in the equation that I have to worry about (well, maybe don't *have* to, but do anyway). I kinda feel like dynamic power "hides" some of the pockets of weak link quality by ramping the power up to accommodate a degrading link. I would rather fly around with constant output power and get a better feel for the link quality in a given situation or location. But that's just my personal preference. I do have the Radiomaster Ranger that goes to 2W but usually just fly it at 250mw. If I wanted to run 2W I would probably turn on dynamic so as not to totally kill my handset battery. Thanks for watching!

[@EnglishTurbines]

@@brubakerjm I see, I don't use 2.4g ELRS. I only use the original Crossfire gear on 868mhz. Most of the time it's on its lowest output at 25mw but can ramp up if needed to a max setting of 250mw. Key is correct vertical orientation of the Dipoles. On my quads, it's horizontal but the signal nulls show themselves sometimes quite close in with jumps in RF to compensate. So, isn't Ghost on 2.4g ELRS chip technology too?....🤔😳🤔🇬🇧

[@sunfpv]

I would like STL pan servo pls.

[@brubakerjm]

This one: www.thingiverse.com/thing:4914046

[@alerx94]

What servo are you using here??

[@brubakerjm]

@@alerx94 On the pan? It's a FeeTech FT90m. It gets about 270-degrees rotation when the PWM outputs are set to 500-2500ms on the flight controller. Plus it supports 6V, which is good because I usually run my control surface servos at 6V or more. www.robotshop.com/products/feetech-digital-servo-2kg-cm-ft90m

[@alerx94]

@@brubakerjm yeah sorry for the dumb question, I opened later the description and saw that you mentioned there the exact model.. How's cg with the servo and the insta 360 go? I fly with an air unit strapped to the front canopy and with a 6s 1300mah it's almost nose heavy.. I'm wondering about the added weight..

[@brubakerjm]

@@alerx94 So up front I have the pan servo, Insta360 Go 2, and the full-size Air Unit basically under than pan servo. I do run an extended motor mount and a heavier-than-stock motor, but with my configuration, my 1,500 6S is pushed back against the rear of the battery bay. I want to try my 6S 4,200 Li-Ion pack, but I'm probably going to need to add some weight behind the CG to get that to balance. Or possibly put it in the rear bay? I haven't worked it out yet. It's so much fun to rip around on 6S I haven't been super motivated to work on endurance times. Oh, I also broke the wood battery tray in the crash, so I printed one in PLA+ and replaced it. That probably adds a few grams ahead of the CG too.

[@joerocket1977]

Great setup and flying all the keyboard pilots all ways have something to say.

[@brubakerjm]

Appreciate your comments. Thanks for watching!

[@Carboneye7]

Those throws were really foolish to do around those kids bro keep your radio in your hand throw with the other.

[@ttucker2073]

I always throw with the radio on the ground. I’ve seen a good few times where people hold the radio with 1 hand and throw with the other hand and crash there plane. One touch of the radio during autolaunch while throwing takes it strait out of the launch and crashes. I know what your saying about the kids but they seemed out the way and I’m sure he was cautious with them.

[@devilsreject78]

My Dolphin also does that now is where it didn't do that before the dip down on lunch never used to do that now it does I don't know why

[@brubakerjm]

Are you using autolaunch?

[@devilsreject78]

@@brubakerjm yes

[@brubakerjm]

@@devilsreject78 I also still seem to fight "the dip" on launch. I suspect that part of the issue is the angle at which the plane is thrown. I think that sometimes I throw the plane too much "up" and the autopilot actively corrects to bring the nose back down, which then limits how fast it can transition to climbing once minimum airspeed is achieved. I actually just flew this Dolphin last week, two flights, back-to-back (with a quick nose repair in-between). One launch (double-handed, backward, overhead throw) resulted in minimum dip (and then crashed because the prop nut came loose and had no thrust!) and the second resulted in a lot of dip with the prop trimming the grass as it just barely made it. Looking at the recordings, I think in the second case, the plane had a much higher nose-up attitude as the plane was leaving my hands. I have a few other aircraft that also fight this dip on launch, and I suspect the same issue. That said, I don't really know for sure. Once my Dolphin has enough airspeed, it climbs out like an absolute rocket ship. The fact that it can be nearly perfect on one launch and then almost a total disaster on the second leads me to believe that it likely has more to do with my throwing than the autolaunch settings.

[@devilsreject78]

@@brubakerjm I have never done an over head throw with the dolphin I might try it though. I do it for my s800, I changed motors for this year in running a 7in tri blade with 4s 2216 1400kv I might try a 8 or 9in biblade. I not sure how it'll work.

[@brubakerjm]

@@devilsreject78 I run 2216 1400kv Sunnysky on my AR Wing Pro with an 8x6 and it flies great. The AR Pro PNP kit actually comes with the same motor but 8x5. I think I have one more plane with that combo but I can't remember which off the top of my head. Too many planes!