Servers by jDrones

Nimbus Tricopter VTOL

(Michael De Leon) #48

Thank you @Aticof

This will be a big help with the community

(Greg Covey) #49

I received my Foxtech Nimbus VTOL V2-Tilting System and was happy with the quality of the parts. I’ll probably still wait for my replacement RDS3115MG servos to arrive since it requires less assembly and changeover.

I noticed that the FoxTech servos in the kit have only a 90 degree swing and the RDS3115MG servos have a 180 degree swing. They even have RDS3115MG servos with a 270 degree swing. Can any of these servos be used just by changing the max/min settings for the tilt?

(Atico) #50

are you sure? Surely they turn something else for yaw vectorial.


(Atico) #51

I read on the Foxtech website that they use a 1755 rear propeller.
What do you think? I think it’s too much diameter

(Greg Covey) #52

Yes, it is nominally 90 degrees and maybe 100-110 degrees with maximum 1000-2000msec swing. The servo used is AGF-RC B53CHL Digital servo.

They changed their rear motor to a X5008 330Kv motor so the 17x5.5 t-style prop is probably fine. I am using the SunnySky X4112S-11 KV400 motor with a 14x5.5 MKII carbon prop.

It looks like they added lifting power to the V2 design once payloads were being used.

(Graham D) #53

Our PG20 dual battery switch arrived today. Has anyone used one of these?

It is switched by varying PWM values, so does one just switch it with the Tx or setup the FC to switch it according to mode (I’m thinking the latter is the better option)?

(Atico) #54

The last it would be the best option. Tell us if it is feasible.

(Atico) #55

One question:

I can not find tables or motor tests for the Sunnysky X2112 400Kv.
I do not know what will be better, 15" or 16" propeller.

What is your opinion?

(Greg Covey) #56


Did you mean 4112? If so, tables are here.

As for prop size, 14" to 16", it all depends on your usage and payload. I would think that different prop sizes would work fine as long as the servo output pwm control is not near a limit. PIDs are adjusted to compliment the setup. The changes in the FoxTechFPV motors and props are likely due to gaining experience with heavier payloads and wind resistance.

In other words, a mapping VTOL will be set up differently than an FPV VTOL or an aerobatic LOS VTOL.

I noticed on my FoxTech V2 Tilting System that they use 7" carbon tubes. On my initial setup, I use 6" aluminum tubes like the original conversion by Kris. It seems that the longer the motor mount tube becomes, the more change in CG you have between VTOL and FF mode, but, there is less prop over the wing. Any comments on this from anyone?


(Atico) #57

Sorry, yes 4112. But in this table and others there is no performance for 16".

(Greg Covey) #58

Correct. It doesn’t mean that you can’t use a 16" prop. Sometimes the easiest way to change your system dynamics is to simply change the prop size. Remember that in most VTOL applications, the idea is to use minimal hover time because forward flight is much more efficient.

(Graham D) #59

Foxtech has kindly responded to my PG20 question on their Facebook page and put some details on their product page:

(Atico) #60

Hi Greg, on the FoxTech V2 Tilting System, if the CG is 100 mm from the leading edge

What is the distance between CG and the tilt servo shaft?

And between CG and the X3520 motor base in plane mode?


(Greg Covey) #61


I measured approximately 220mm between the CG and tilt servo shaft. Add another 35mm to reach the motor base.


I am a bit leary about the PG20 as it adds complexity and does not have a track record. What duration do you hope to obtain that cannot be done by simply using two main batteries for two flights? Perhaps I am thinking more of mapping and your goal is longer FPV flight?


I received my new RDS3115MG servos from Amazon and was happy to discover that they are really the same 180 degree servos like I had before and not 270 degree like the site promotes. For $16 each with free 2-day shipping, they beat my order from Banggood which is still in transit.

I installed the servos and powered up my Nimbus and aligned the motors for QSTABILIZE and FBWA flight modes. The servos seem to work quite well and the Sunnysky X3520 520Kv motors really spin nicely!

My currently issue is that the front motors only spin when armed in FBWA mode. In QSTABILIZE mode, only the rear motor spins. The robot servos do properly point the front motors up. I will check my servo connections today as I ran out of time last night.

(Atico) #62

OK Greg, I think is better 19,5mm (6") between the CG and tilt servo shaft. It will be easier to balance CG although the propeller overlaps more over the wing

(Greg Covey) #63

I must have been brain dead when I connected the throttle because I connected the stock “Y” cable to output 3. You need to split the throttles apart and connect the left ESC control to output 6 and the right ESC control to output 5. My setup seems ready to add the props and do a final alignment. It is rainy and wet today but I should be able to try a hover test tomorrow (Sunday). Fun stuff!

(Greg Covey) #64

My wife took the grandkids to get pumpkins so I seized the opportunity to put the props on and go for a backyard test. Guess what, it hovers! :slight_smile:

I’ll look to get some photos or video tomorrow. All the stick directions seemed correct so I moved it out into my backyard that has lots of tree and bush hazzards. In QSTABILIZE mode I seemed to have good control. One issue seen was a back and forth yaw movement which was being done by the front motors slowly yawing maybe ±5 degrees. I am used to quadplanes or my FF6 that uses motor speed for yaw so I am not sure what parameter I can tune to reduce this issue.

(Graham D) #65

That’s awesome Greg, have you had a chance to try QLOITER?

I have managed to get rid of most of our tail wag with the following params:

It’s not perfect but the tail is almost now without any yaw variation.

(Greg Covey) #66


Thanks for the parameters! I’ll give them a try tomorrow. I only use QSTABILIZE initially in my backyard because it is a very small area surrounded by trees and an upper canopy. When ready, I’ll take it to the park and check the BARO and GPS modes. I had three hovers today and it’s still in one piece so I was happy.


(Greg Covey) #67

After my intial hovers, I decided that I never really did a good job aligning the front motors so I used a yard stick and a level to fine tune the front motor up and forward positions. The tail boom, level, and front props are all in alignment now.

Since I am likely to take off the props during my test, I didn’t used the 6mm lock nuts but used the nut and spinner that came with the Sunnysky motors for easier removal.