Multirotor, multicopter and quadcopter discussion - The Drone thread

I found this guide which explained both the science and the tech of how it flies.

Do more expensive quads automatically compensate for loss of lift when you pitch in a direction? I would have thought that would more of a hindrance than a help (if you know what you're doing)
 
Guides are a bit subjective, depends what takes your interests.

Generally, bigger the frame, the bigger/slower your motors. Motors are chosen to suite the required thrust to lift the frame. If you don't have a 2:1 power to weight ratio, it will be sluggish. ESCs are chosen for the motors based on nominal/burst current. For example, an 1806 sized motor may draw 8-9A at wide open throttle. You COULD get away with 10A ESC, but it would be on the ragged edge and not accounting for Chinese tolerances :p 12-20A would be a better choice in this scenario, but anything bigger would be severe overkill price and weight wise. ESCs have micro controllers which run their own program separate from the flight controller, the two biggest camps being BLHELI and SimonK. BL seems to have come on leaps and bounds lately, so would probably be the better choice, I won't even start on OneShot/active breaking (damping), as that's a whole other topic. For larger craft, these considerations are less important, most ESC software will be more than fine for a 450+mm frame,

Flight controllers are also a matter of what you want. Naze32/CC3D/Flip32 all run on similar hardware (STM32 ARM CPU) and are the in thing for smaller craft. On the Naze32 anyway, there are two versions, a "FunFly" which is basic sensors and a "Full", which includes a barometer (rough altitude hold) and a magnetic compass (course hold). There is also the KK boards from HobbyKing, which include an LCD screen for tuning in the field, but these are only 8bit CPU and have limited usefulness (IMO). Some people love these, I've found them a PITA, where a Naze32 will fly pretty much anything stock, my KK2.x boards have required a lot of tuning/fettling. They are both collecting dust now...

What the new breed of 32bit controller lacks is solid GPS/compass support. They all CAN run GPS for return to launch, position hold/loiter etc. These features are at the mercy of the community and may or may not ever be 100%. TBH I don't know anything about the more "professional" solutions from DJI, and the likes of the Ardupilot project as GPS has no interest for me. I'd rather buy a balloon to drag about :p

FPV can be as complicated or as simple as you like, and the price has tumbled tremendously since I started.

If you want to get started with a cheap 250, which is an excellent entry to multis, this series from Bruce might be handy




 
Cheers for the reply DJ,
Ive narrowed it down to a couple of These
They should be ok?
What does the C (as in 25C) mean? Is it the higher the better?

Just a charger to look for now, any reccomendations chaps? (about £50 ish)
 
almoststew1990 said:
I found this guide which explained both the science and the tech of how it flies.

Do more expensive quads automatically compensate for loss of lift when you pitch in a direction? I would have thought that would more of a hindrance than a help (if you know what you're doing)
Click to expand...

It depends on the flight controller, but in general yes.

A small 250 sized quad will likely not have GPS or altitude hold, so you are in full control of the throttle. When you manoeuvre about you will need to modulate the throttle to keep a consistent altitude to compensate for the varying thrusts of the motors.

Larger craft from 450 upwards usually get built with altitude and heading hold, or full GPS controllers. These will place a layer of electronic control between the pilot and the motors to remove the need to control them all manually. the main reason for this 2 fold, firstly bigger quads are more expensive and more dangerous, so assistance to avoid crashing is always welcome. and secondly, larger quads are used a lot for aerial filming or photography, so the pilot is able to focus his attention on lining up shots without having to also worry about things like holding the right altitude or heading.

For a lot of GPS models you can let go of the controller and the craft will hover stationary in the sky. A fully manual 250 style craft will not. Think of it like cruise control, ABS and power steering in a car. A 250 is a Caterham 7, while Russ' 8 rotor filming rig is a Maybach.
 
The C is the maximum discharge rate of the battery. Simply put it's the the max. amount of current in amps (A) the battery can manage to supply using the following calculation:

Battery capacity x C rating = max amps can be put out by the battery.

E.g. 5,000mha battery x 25C = 125,000 milliamps, or 125 amps theoretical discharge rate.

As a (simplistic) guideline if you are running 4 x motors maxing out 30A ESCs , you need 30A x 4 of current = 120 amps from your battery at full throttle. So that would be enought.

For multirotors you want some breathing space though, running the battery at max discharge rate will a) not give you enough top end power b) reduce the battery life or even damage it.
 
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Skeeter said:
snip...

For a lot of GPS models you can let go of the controller and the craft will hover stationary in the sky. A fully manual 250 style craft will not. Think of it like cruise control, ABS and power steering in a car. A 250 is a Caterham 7, while Russ' 8 rotor filming rig is a Maybach.
Click to expand...

Great explanation. It's not only a Maybach but one with driverless capabilities :)
 
mingeroonie said:
Cheers for the reply DJ,
Ive narrowed it down to a couple of These
They should be ok?
What does the C (as in 25C) mean? Is it the higher the better?

Just a charger to look for now, any reccomendations chaps? (about £50 ish)
Click to expand...


im using turnigy nano-techs, this is mine i think

http://www.hobbyking.co.uk/hobbykin...gy_nano_tech_5000mah_4S_25_50C_Lipo_Pack.html


C Rating explained

https://www.commonsenserc.com/page.php?page=c_ratings_explained.html

:)

I dont know a great deal about the C rating stuff tbh, I just buy what other people tend to buy


My 450 I use the 5000mah 4S 25-50c

my 250 I have 1 x 1300mah 3S 45-90 C and 2 x 1300mah 25-50c
 
Skeeter said:
Am I heading for a world of hurt if I start trying to solder 2mm bullets?
Click to expand...



NO! IT WILL BE UN-NEEDED WEIGHT :mad::p

I say if you can do it and keep it neat, and still have the bend radius to keep the wires tied up, go for it, it surely cant add up to that much weight.
 
So Im looking at picking up the Syma X5C-1 does anyone have any experience with it and do you have any tip on what to buy in the way of spares or upgrades? Thanks
 
Well I'm officially grounded I've accidentally knocked my transmitter off the kitchen table and snapped the anttenna and can't find a replacement anywhere so looks like I've got to get a new transmitter

Unless anyone knows where I can get a new anntenna for a devo 10

Another 1 I'm looking at is a turnigy x9 anyone rate these ?
 
DJMK4 said:
NO! IT WILL BE UN-NEEDED WEIGHT :mad::p

I say if you can do it and keep it neat, and still have the bend radius to keep the wires tied up, go for it, it surely cant add up to that much weight.
Click to expand...

My crafts getting tubby as hell so I'm considering chopping the motor and ESC wires right down to the minimum possible, but I want to keep the bullet connectors for easy replacement.

Actually, I might cheat. They all have bullets already, so I could just cut a chunk of wire out the middle and solder the 2 bits together, not touching the bullets :p
 
kPATm said:
So Im looking at picking up the Syma X5C-1 does anyone have any experience with it and do you have any tip on what to buy in the way of spares or upgrades? Thanks
Click to expand...

I bought this just the other day. It's my first quadcopter although I've messed around with RC helicopters a fair bit.

Ignoring the fact that I was sent the wrong one (without a C means no camera, without the -1 means older version, so double check when yours arrives) I really like it. I asked on this thread and was advised that two good choices are the Husban 4 something and the Syma. The Hubsan is smaller and as I was going to do outdoor flying I got the larger one.

It flies stable and surprisingly smooth (maybe all quads do); it is a 350 span quadcopter rather than the 250 of the Hubsan. It isn't quite as agile as you'd imagine.

Video is of average quality (crap lense) and is recorded at 720p. Photos are disappointingly poor- you remember how on old 2mp digital camera the photos would be substantially better than the video- that isn't the case as photos are literally 1 frame of video. I might upload a video later if you want. The camera points down a little too much for my liking but some celloptape bodging will fix that. It comes with a 4GB memory card which is big enough, and also a usb to microSD adapter which is nice. Just don't forget to put the card back in the helicopter like I did :(

The battery connectors are the same style as PC 3 pin fans. Considering you have to disconnect the battery to charge it, I don't imagine that this connection will last long. Batteries themselves are cheap (I've got two larger 600MaH batteries on the way, for a fiver) and as this larger copter will appreciate open spaces, you'll likely travel a bit to fly it, so grab a few batteries.

It seems to be a good introduction to quads basically!
 
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Thanks mate. Where did you buy from. TBH if they sent the wrong one I would send it back as the C-1 is supposed to be a pretty good upgrade from the standard X5. I have seen one on Amazon for just under £40 but they havnt replied to confirm it is the C-1.

Is that £5 for the 2 batteries or a £5 each?
 
Here's my current rig, a bit bashed up but ready to go in this gorgeous sun!

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hPXpovel.jpg.png
 
Looking good, going to give it a miss today as its a little damp outside, and I have things I need to do, but I need to finish putting my 450 bits together after its clean.


Whats the performance like on those 3 blade props over 2 blade?
 
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