Parramatta Radio Control Aircraft Club
channel questions !!! tx/rx - Printable Version

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channel questions !!! tx/rx - wingtipper - 21-12-2012

hi , as the dx18 has been released , i was wondering if anyone can give an example in detail , of how all these channels would be utilized in an aircraft or heli . even 12 channels utilized i'd be interested to hear .
Start thinking guys !!! waiting for answers . cheers .

RE: channel questions !!! tx/rx - BenR - 21-12-2012

Well the plane I want to get to one day is 12 channel - its this one.

http://sydneyrcjets.com.au/electric-fighter-rc-jets-70mm-edf-jets-c-8_12/12ch-lx-f18-super-hornet-twin-vector-thrust-rc-edf-jet-pnp-p-360

Of note is this line...

12 Channel Full Function Radio Controlled (Aileron, Elevator, Throttle, Rudder, Retract, Thrust Vectoring, Airbrake Flaps)



RE: channel questions !!! tx/rx - wingtipper - 21-12-2012

sweet , thats seven functions . why the 12 channels ?
by the way what a beaut EDF .

RE: channel questions !!! tx/rx - kizza42 - 21-12-2012

When you get into larger aircraft life Jets, you generally have a channel per control surface so the plane can be tuned perfectly.
Take an F15 Eagle:

Aileron L
Aileron R
Flap L
Flap R
Elevon L
Elevon R
Rudder L
Rudder R
Gear
Brakes
Airbrake
Nosewheel Steer
Engine 1 Throttle
Engine 2 Throttle
Engine 1 ECU
Engine 2 ECU

16 before you even chuck in say a Gyro or scale features like canopy or lighting.

RE: channel questions !!! tx/rx - gbanger - 21-12-2012

I don't like to sound like a smart arse but you will probably find that all those other systems need their own channels, canopy, air brakes, flaps at least 2, thrust vectoring will need at least 2 quite possibly 3, not to mention the fact that ailerons would use 2 channels, rudder is probably 2 channels, if the retracts use a sequencer for the doors there is another one, they add up pretty quickly.
Oops I almost forgot the folding wings... shit!.. have you got enough channels?
So when you add em up properly you will find it's a good idea to have a couple of extra channels when the aircraft start getting bigger and more complex. Doing a system mix is always going to give you a lot more adjustability and control precision on all these systems rather than using crappy Y leads etc.
Gazz

RE: channel questions !!! tx/rx - secant0give - 22-12-2012

don't forget wheel breaks need a channel for that by it self

If you use dual rudder and put one out each side for breaking then you need two one for each rudder
and one channel to mix in the offset so they both go out together and still move with the rudder stick and then you will need a seperate one for the nose wheel.
OK that's 4 just for rudder

One for each aileron 'cause you want to use differential

one for each elevator 'cause you want to mix the with aileron to up the roll rate

that's 9

And we havn't even mentioned FPV stuff like pan and tilt for the camera thats another two
one to set RTH (return to home) another to set alt hold on an off and another to toggle the OSD display on and off. thee's another three, so that makes it 12

Oh I guess I might need throttle as well, 13 channels

perhaps I might want to use retracts too that 14

Flaps could be handy a channel each for those so I can do crow breaking and mix them both in with ailerons for max low speed handeling. that's 16

Hmmmmm how am I going to set up my air breaks or my drag chute deployment ?? or drop water balast ?? I've run out of channels ???

RE: channel questions !!! tx/rx - wingtipper - 22-12-2012

well thats a detailed explanations . thanks to all who replied. i must say it would be a load of fun electronicaly setting up , then customising mixes etc . for such a beast , but i would imagine seveal thousand dollars would be involved there . i'd better brush up on my flying skills over the next 2 years , GEORGE on the other hand .

RE: channel questions !!! tx/rx - Skidz - 22-12-2012

And then you have to wire them all up (somehow).

http://www.futaba-rc.com/sbus/index.html
http://www.rcmodelreviews.com/futabasbus.shtml

RE: channel questions !!! tx/rx - secant0give - 22-12-2012


Good old Futaba ay !!

That looks like a nice system and probably the locical next step for large and complex set ups.



RE: channel questions !!! tx/rx - gbanger - 23-12-2012

I will stick with JR/Spectrum thank you very much
Simple and reliable with built in redundancy, and a dam site cheaper.

http://www.spektrumrc.com/Products/Default.aspx?ProdID=SPMAR12120

RE: channel questions !!! tx/rx - popeyepete - 23-12-2012

That Futaba is some complicated sh!t, why would anyone????

I'm with you Gazz, Spektrum = simple

RE: channel questions !!! tx/rx - robair - 23-12-2012

G'day All

The sbus system looks like a twist on what I have been using on my model railways for years. It's called DCC or Digital Command Control and could easily translate across to model aircraft. It is heaps simpler from the wiring perspective however does require a bit of set up shennanigans.
Google DCC and you will see what I mean.
The Futaba system lacks a dongle that allows other brand equipment to hang off it.
They lose my vote to JR/ spectrum primarily for that reason alone.
Back in the late 80's my mates and I used to drool over a new 4ch Futaba tx that cost a bazillion $. We described Futaba as "fundamentally undermining total assets bank accounts".
Nothing has changed it appears.

And, yes, it is pretty easy to get up to 12+ channels required.

Cheers
Rob B

RE: channel questions !!! tx/rx - kizza42 - 23-12-2012

Hobbyking Sbus coming soon!

Personally prefer multiple channels/signal paths of redundancy.
I know of a few rc jets that have likely gone down from fried elevator servo cables.

RE: channel questions !!! tx/rx - wingtipper - 23-12-2012

awesome stuff fellas . i can now see the next stages of my electrics for dummies , coming into play . really exciting stuff for me anyhow . sbus eh .
similar to profy bus , and then the next stage optical fibre . , and of course pilotless flying . lol
these are all the things coming on the 1400 tonne ZPMC gantry AC cranes i work on . funny how the big stuff directly relates to the small stuff . LOL . I'm a fitter by trade but its pretty to watch and learn .
i really love this RC stuff .