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Can I build a simple multi-rotor using airplane parts? Advice Needed!! PLEASE!!

#1
I’ve asked this question to local hobby shops and nobody can seem to help me so I thought I would ask you!! PLEASE HELP!

I'm building my first multi-rotor and I know nothing about flight controllers, PDB boards, and programming... I fly simple fixed-wing aircrafts.

The multi-rotor I need to build only has ONE purpose: to carry a heavy payload (5 lbs minimum) and drop said payload using a mechanical servo (like the ones FliteTest rigs up on their airplanes) attached to the underside of the drone.

I've been flying "fixed wing aircraft" for year several years now and I want to use the same equipment that I have to fly big airplanes to build this multi-rotor… such as my: FrSky X8R Receiver and Taranis QX7 transmitter, along with some BIG brushless (Turnigy SK3) motors, 80A Hobbyking speed controllers (w/sbec), swinging 13”-15" props, and mechanical servo bomb drops that I already have on hand from all my airplane builds... (That way when I’m not using the multi-rotor I can use the equipment back in my fixed-wing airplanes). I will make the frame using the same technique as in the old FliteTest "H-Quad" series.

The older "Naze32 Rev6" flight controller was most commonly used for these types of (PWM) based multi-rotors several years ago however I read somewhere that CleanFlight and BetaFlight no longer offer programming support for the old "Naze32 Rev6" flight controllers. Which SUCKS!!!

Is there a current flight controller on the market that is similar to the older "Naze32 Rev6" board that can handle inputs for servo functionality such as "bomb drops,” etc. ??

The ONLY purpose for this multi-rotor is to carry heavy (5lb - 8lb) bait out to sea from the beach when surf-fishing for sharks thus replacing the need to paddle my bait out on a kayak. I’m not interested in small, fast, race drones with tons of sensors. I need a simple, yet powerful multi-motor that can lift weight.. (I own an old "DJI Phantom 3" but it can only lift 2.5 pounds... not good enough for my application.)

I need to fly 400-600 yards off the beach and be able to hit a switch on my transmitter and have a mechanical servo drop the bait down to the water and I DON'T want to have to use 2 separate transmitters and receivers in order to achieve this... I would like to find a flight controller that can handle the entire operation.

Questions:
1. Is it possible to still build a multi-rotor using basic airplane parts? ... like the old "FliteTest H-Quad"
2. What kind of flight controller and PDB board do you recommend that is NOT outdated?
3. Do you know of anyone in the southeast who could mentor me and help me on this project? ... (I live in Alabama)

Thanks everyone!!!! :)
 

ElectriSean

Eternal Student
Mentor
#2
I think you are confusing inputs and outputs here. The inputs to the FC are the receiver (your X8R can do PWM or SBUS) and it's onboard sensors (gyro, accelerometer). The outputs are the ESCs/motors and any additional servos. All FC's can output PWM, and all FC's accept SBUS input, though newer FC's do not accept receiver PWM inputs.

So, to answer your questions:
1. Yes
2. Any F4 or F7 based FC will work, many are "all in ones", meaning they combine the FC and PDB
3. Can't help you there, but you can learn everything you need to know online :)
 
#3
Thank you for your reply ElectriSean!!! After numerous attempts on forums you're the first person who has offered a reply and I really appreciate that!!

So I can take my receiver (X8R) and wire it to a Flight Controller using it's SBus connection and have the FC recognize the additional auxiliary channel that will ultimately control a bomb-drop release mechanism?

The other thing I'm confused about is what happens to the sBEC port on fixed-wing ESC's and how does the built-in sBEC port work with a power distribution board and Flight Controller? Does the FC just ignore the fact that the ESC already has a built-in sBEC port?

- How about this Omnibus F4 ?? I can't tell if it has a built-in PDB or not... Do you think it's a good match for this build??
https://www.amazon.com/dp/B07B9VM898/?tag=lstir-20

- What about this PDB board ??
https://www.amazon.com/dp/B06ZYFY89Z/?tag=lstir-20
 

ElectriSean

Eternal Student
Mentor
#4
Using SBUS gives you up to 16 channels depending on how you bind. You'll have to set them up in your radio of course, and the servo will take extra setup in Betaflight or iNav.

When you connect the FC to the ESC's, you do not connect the red wire from the BEC, just the signal and ground. You can and should use one of those BEC's to power any servos you are running, so that a stalled or malfunctioning servo/brownout won't kill the Rx or FC and make you drop out of the sky.

The Omnibus is a nice FC, but it does not include a PDB. The Matek PDB is decent, those 2 items are a good combo.
 
#6
Thank you for all the help! Attached are the motors, esc's, props, flight controller, and PDB I'm considering getting... I think I want to go with the Hexacopter layout that utilizes 6 motors for more stability and power. So just eye-balling it, do you think these components put together can roughly lift "5 - 8 lbs" of payload?

I have a DJI Phantom 3 and it can lift 2lbs so surely these components can lift more than that, right? Any feedback is greatly appreciated!!!
 

Attachments

ElectriSean

Eternal Student
Mentor
#7
I've never run motors that big, I'm not sure what they can do for thrust. By the specs though, I think that PDB is undersized, and only provides enough pads for a quad.
 

"Corpse"

Well-known member
#9
I've never run motors that big, I'm not sure what they can do for thrust. By the specs though, I think that PDB is undersized, and only provides enough pads for a quad.
I took a look at the board and there are six B+ pads and 6 ground pads. That should be enough for all the esc's he's running.

I will say this @tristantrc, bigger multirotors are harder to tune and sometimes fly. The best advice on tuning, building and flying would probably come from X-class drone racers like Zoe FPV. They are wizards when it comes to tinkering with these sized quads. If you can contact someone like that they could definitely help your hex fly much better! Good luck!
 

PsyBorg

Wake up! Time to fly!
#10
Something to ponder about this project...

Most of us fly quads as a hobby along the lines of sport flying. Heavy lift usage is a completely different animal. I think setting a project up under those requirements using parts designed for agility is setting yourself up for a major disaster. There are too many factors in doing this to be addressed in a forum thread so Im not going to bother.

The main point to focus on is not so much the lifting and carrying as Flite test has proven time and again that anything can fly given enough power. The issue comes when the release of a payload that heavy transitions the weight loss to the air frame. The factors that will create upon release on the air frame alone with reflex of the arms could easily throw an FC into failsafe or smoke esc's trying to compensate. That doesnt even consider the FC's tune as a light multirotor will require a very different tune then a heavy one. You want to fly under both conditions in the same flight.

Suffice it to say most "Heavy Lift" multirotors use collective pitch and themselves are higher in mass to support the weight it carries in a manor that does not produce the typical issues we face with more agile hobby craft.

With all the bad press as well as you being new to all this you might want to put this project on hold for a while and start with a small build, learn to fly in non assisted modes first while you research more on what you want to accomplish rather then go on happy confirmations of your ideas on a friendly forum.
 

ElectriSean

Eternal Student
Mentor
#11
I took a look at the board and there are six B+ pads and 6 ground pads. That should be enough for all the esc's he's running.
You're right about the pads, I was thinking the battery connector took a set, but now I see my mistake. The overall power rating is still undersized though, from the specs:

ESC outputs:
-Continuous current: 25A*4 or 15A*6
-Peak current (10 seconds/minute): 30A*4 or 20A*6

Those motors will draw up to 37A each, well over double the continuous rating.