Long range DIY autopilot drone, mainly Pixhawk questions

Kerotan1989

Kerotan1989

New Member
Hello,

I have a friend who needs a fairly long range drone (say about 4 miles or so) that can take off, follow a GPS route, return home and land, all completely autonomously. I've done a fair amount of research into my own build, and am fairly certain on a few things, but a bit confused about some other things.

So here's the things I'm pretty sure will work well together for the type of drone we need

Tarot 650mm Ironman frame
Tarot 4008 330KV motors
30A HobbyWing Platinum Pro ESCs
Tattu 6S1P 10000mAh 15C battery
15" diam 5.5" pitch props, carbon fibre or plastic

now the stuff I'm a bit confused on

Pixhawk Radiolink with GPS OR HolyBro Pixhawk PX4 with GPS (similar to HolyBro Pix32?)
FrSky X8R receiver (EU firmware, we're British)
FrSky Taranis QX7 2.4GHz transmitter

All up weight - ~2780g, including camera and gimbal (not mentioned above)

So here are my questions (a fair few, but any help would be appreciated)

Drive components

1. Will the selected drive components be compatible with each other and the weight of the drone? I've
put it all through eCalc and it seems okay, but a bit of human advice or warnings would be great.

Flight controllers

2. My understanding of the Pixhawk devices is that the Radiolink is best suited to using APM (ArduPilot), whilst the HolyBro is optimised for PX4. Is this accurate?

3. What we really need is pre-flight GPS route planning, telemetry monitoring, and some very basic RC control just for the PID tuning and testing the drone (as stated, the plan is for it to fly fully automated). This is why we're looking at Pixhawk, because the available software seems good for the job. The only part of that that would need to be fairly long range is the telemetry.

With all that in mind, could someone(s) who's worked with these devices before perhaps recommend a good telemetry setup for each of the flight controllers?

4. Power to the FC. From looking around, I thought the easiest way to power either of the Pixhawk flight controllers would be to use a power module directly between the battery and the FC. For the HolyBro, I was going to use the HolyBro APM 10s power module. Would this work, and would the same power module also work for the Radiolink?

5. What is the difference between , the HolyBro Pix32 and the HolyBro Px4? I'm struggling to find a good history of Pixhawk models to compare the two, and can't even tell which is more recent, and so a bit of advise on this would be great.

6. For either flight controller, I'm not quite clear on how to set up telemetry, and what hardware to use to match the various firmwares. Could someone suggest a good telemetry module for the Radiolink and also for the HolyBro?

7. Finally, I'm fairly sure that the FrSky transmitter and receiver I mentioned above would be compatible with either flight controller. Is this the case?

That's it! If anyone can give any advise at all I'd be eternally grateful.

Thanks,

Tom
 
Your drive components like compatible, I personally use 40 amp ESCs just to be sure but the 30 amps will be fine. As for the radio, the Radiolink is OK, I used one for quite a while, but I'm not sure about a long range module for it. For your purpose the FRSky QX7 won't work well as it just doesn't have enough 3-way switches (in fact it may only have 1). My suggestion would be to use the FRSky X9D + with the Crossfire module. This is basically the go-to setup for long range flight. And some may disagree, but I would scrap the PixHawk and go with the EagleTree Vector. Just because it is much more user-friendly, does everything you want and more, and the OSD is second to none.
https://www.getfpv.com/radios/radio...ranis-x9d-plus-2-4ghz-accst-radio-mode-2.html
https://www.getfpv.com/tbs-crossfire-tx-long-range-r-c-link.html
https://www.getfpv.com/tbs-crossfire-8ch-diversity-receiver.html
https://www.getfpv.com/eagle-tree-vector-fpv-controller-with-color-osd.html
 
The QX7 has four 3-way switches. How many do you feel is needed for long range? What would they be used for?
The S9D has six.
 
So on my T650 Sport with the Vector, I have:
2 X 3-way switches for different flight modes
1 X 3-way switches for camera switching
2 X 3-way for different OSD screens (definitely not required but fun to play with)
 
Thanks very much for all the replies so far.

@ RENOV8R Thanks for the suggestions on ESCs. I may go for Hobbywing 40A ESCs anyway as I've heard they're good from various places.
On the QX7 vs X9D, we plan for the craft to eventually be fully autonomous, and thus not having any user controls during flight, only telemetry communication with a control centre. We'd only need the controller to tune the PID settings, test out the drone at short to medium range, and when checking the RTH and autopilot work well. I feel like this means we probably don't need all the power of the X9D and crossfire?

I'm interested by your suggested of the Eagle Tree Vector instead. I've heard of it but haven't done any research into it so will take a look.

If I was to go for a Pixhawk, I think it's likely to be the Holybro. The thing is, I quite like the look of ArduPilot over PX4, and have heard it's typically more stable and better tested. Does anyone know if the HolyBro Pixhawk will take Ardupilot instead of PX4? It says it's APM compatible, which I assume is supposed to mean the same thing, but just wanted to make sure.

EDIT: On the telemetry issue in my original post I think I've figured out my confusion, and would plan to run separate telemetry antennae connected to the flight controller, set up for long range comms to a control centre.
 
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