Nimbus Tricopter VTOL

Ok, I moved the wires a bit and put the ferule on, no more twitching (for now at least).

I’ve fixed all of the issues I know of, would anyone mind taking a look at my parameter list and see if anything obviously wrong is going on? This is an important build for me!

Nimbus VTOL V1.2.param (17.1 KB)

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I can’t remember if you are just hover testing the Nimbus or plan a transition to forward flight as well.

If you stick to using only FBWA mode for your maiden forward flight, you’ll be fine. However, if you decided to use CRUISE or LOITER modes, I would not enable your AS sensor until it has been calibrated once. Rolf has recommended even doing this on the SDP33 sensor.

For first flights without an AS sensor.


After a calibration flight of simply flying in CRUISE or LOITER mode for 10 minutes…then check the log for Air Speed vs. Ground Speed. If the results look reasonable then enable the AS sensor.


If you are not carrying a payload, you could change your settings below,


to a lower value like these. This keeps the plane from flying too fast when the AS sensor is disabled and you keep the throttle at mid-stick. It will also transition to FF sooner.


Your flight modes have me a bit concerned.


As with any “copter” testing, the preferred method is to start without sensors. I use the flight mode sequence below.

  • QSTABILIZE (Pilot)
  • QHOVER (Pilot and BARO)
  • QLOITER (Pilot, BARO, and GPS)

Once the copter testing has finished, I used this sequence below. When transitioning from a forward flight mode, it is (or was) considered a bad idea to change to QLOITER mode as the vehicle is stressed to stop as quick as possible due to GPS. I am not sure if that has changed but I never do it.

  • FBWA
  • QRTL or AUTO

Good luck!


Hi Greg:Ok i.m trying to set this up but really don’t know how it’s supposed to look and act like in Q stab, when checking the controls IE do ail work and vtail ,motors what position should they be in etc? when i put power to it both motors go up left side about 80 deg,right side 90 deg i get no movement at all from the Ail’s the V tail goes up 5or 6 deg and theirs no movement from them either? All three motors start and when i use Ail stick control my motors act like AIL but the ail flaps don’t move nor does the Vtail flaps only the motors speed and direction are going to keep it stab like one of my drones.Thanks B.K

Hi: Can someone point or tell me how to adjust the 2 front motor servo’s to get them properly aligned either by in the Taranis or in MP i’m drawing a blank


Start out by using a servo tester to see that you can properly position the servo…both up and forward. If not, you need to change the mechanical connection so that you can obtain this.

Next, you can control the position fine tuning using the APM flight modes (QSTABILIZE for Up and FBWA for Forward) by changing the SERVO9_MAX, SERVO9_MIN, SERVO10_MAX, and SERVO10_MIN settings in Mission Planner.

See if this works for you…

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Thanks Greg: I’ll give that a a try,now i had to send for a couple of [Dubro Products Safety Lock Kwik Link 2mm for control horn the ones i got were crap and i received the airspeed sensor today something else i need to learn whew.B.K


I need to adjust some trims but other than that she was rock solid!


@Greg I’ll do those adjustments when I am ready for transition, I like to make the hover perfect before I actually fly (so I can always rely on hover).

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Chad: Congrads Very Nice Build

The local club added some paths from the flying field into the woods so I decided to try my S100 mapping camera on the Nimbus VTOL. I use the BirdsEyeView gimbal mount for the S100 which is similar to the Feiyu Tech G3 Ultra gimbal mount with the same vibration dampening. This has proven to work nicely in the past on my FireFLY6 VTOL.

The mapping camera can be set up for autonomous mapping using the Pixhawk and Mission Planner for control or directly from a switch on my Horus X10 when flying manual passes in CRUISE mode. Note that the ImmersionRC video transmitter is for the 2-axis camera in the nose, not the S100 mapping camera. The last image shows the Yaapu telemetry mapping screen on my Horus X10 using Google Maps images.

I’ll post some results after I stitch the photos together. Fun stuff!


Man, that transmitter Greg, is looking better and better every time I see it.

I did a very thorough 1 axis accel calibration for my bird (using leveling bubbles on top of the autopilot) and then re-calibrated my transmitter and between those two things my bird hovers in place like a champ!

I used the cannon S100 for a LONG time! Very good starter camera, I loved mine to pieces! I have now switched to the MAP-02 and will be working on the attachment after I get transition testing completed.

She is weighing in at 7.51 pounds without battery and without payload. The battery I am testing with is an 8000maH 10C 6S.

She has a carbon fiber 17x4.5 prop from foxtech on the rear and I am using a 13x8E APC brand pusher/tractor props for the forward motors.

AND, in celebration of the Cannon S100, here are my models for mounting them:

S100 Underslung Craddle v2.STL (504.7 KB) This one uses two 1/4in wooden dowels glued into the foam wing as hardpoints for attachments. Use a servo rod (thin one) to lock it in place after you have glued in the dowels and match drilled the rod holes in the model with the wooden hardpoint dowels.

S100 Internal Cradle v3.STL (421.8 KB) I used this one with the Buffalo FX79 but I’m sure it will work for a lot more airframes.

Phantom Cradle.STL (419.9 KB) Internal Phantom FX flying wing mount.

Cannon Powershot S100.STL (74.9 KB) This model is accurate enough to use to make your own S100 mounts with.

My bird wants to hover around 30-32 amps with a 2.09lb battery, does this agree with other’s hover power consumption?

I am guessing that forward flight will be around 13±2amps when in cruise mode, is that a good guess?

I am also unable to disarm after I have hovered in QLoiter mode, the motors keep spinning at the armed and throttle at zero speed (5% throttle I believe). I have to use the GCS to disarm. I expected it to auto disarm upon detecting a landing. Any ideas?


Hi Chad,

I am happy to see that you have used an S100. I would love to have a MAP-02 but without a need, it was too expensive for my hobby use. Thanks for posting the STL files!

Your current measurement is right on the money. My measurement below is from last Fall using a 6s 10AH pack. For forward flight, your guess of 13amps is also correct. It will depend upon your throttle setting and ARSPD_FBW_X settings. My Nimbus ranges from 8-23amps for a 20m/s speed. Once I realized that my Nimbus can fly much slower, I have changed my settings as below so that mid-throttle in CRUISE mode flies around 16m/s. Keep in mind that I have lower flying weight using only a Multistar 6s 10AH pack and smaller cameras for payload.


It looks like your ARMING_RUDDER is set to 1. You need to change that to 2 in order to disarm via the rudder. Using 1 is a protective mode for applications that use lots of rudder.


hi @GregCovey, hi all, i just wonder… all this time i use xrotor 40a ESC and this ESC is little bit too often fail… either is death, burned or just lost power unexpectedly… i think i must find another replace more reliable ESC… can u all share to me what the most reliable ESC for nimbus vtol…
PS: if i use SUNNYSKY X4112S 400KV + 1555 prop and SUNNYSKY X4112S 485KV + 1455 prop


I’ve had the same problem with “non name brand” ESC’s. I piledrived an X8 flying wing into the ground at 86mph due to failed ESC once.

On this build I went with everything Foxtech does for their VTOL builds but if I was to go with something else I’d go Castle Creation ESC’s any day along with OS Max or E-Flight brands.

Be sure to look at your motor’s top rated steady state current and then multiply that by 1.2 so you have a nice buffer of using only 80% of the ESC’s maximum rating. This is done due to poor heat dissipation issues and it allows the ESC lifespan to be as good as it is manufactured to be.

Xrotor 40A are heating a lot. It needs to add dissipator with gpu thermal compound. I fly in tropical area and they are not reliable : my tarot 650 with x4108s 380kv failed a lot due to these esc (burnt in flight). Long wire between battery and esc are bad, it’s better to have long wires between esc and motors.

Castle creations bec’s fails a lot due to conception (short circuit between two pole), I don’t know about their esc but not what I will choose …

Any specific recommendation ESC for my nimbus beside Hobbywing Xrotor 40A? or i just use Hobbywing Xrotor 60A?

Pro version have better dissipator : foxtech use xrotor pro 50A at this time

thank you… maybe i will try this…

I agree with this. Sometimes the designs do not allow for this so thicker power wires and/or capacitors can be used.

I also agree with this. :slight_smile: Perhaps this is why FoxTech changed to the Pro version.

I have not had any issues with Hobbywing XRotor 40A ESCs on my setup. Perhaps keeping them external (outside the housing) and flying in the NorthEastern region of NY has made the difference.

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yes i think ur right, flying in the hot tropical part of this earth make it more fragile… for hobbywing xrotor 40a

Hi Greg: i got a Speed sensor in but it only has a 3 wire servo connection the one i bought says for apm2.6 & pixhawk so would you know what aux port i need to plug it into or doesn’t it matter and does the pixhawk know that it’s a speed sensor or do i need a different sensor,i’m still waiting on 16.5.5 props to try a Q Stab Test