aeajr

My Feedback: (2)

I see these 10+ channel transmitters and have to wonder what use people have for all these channels.

My most complex plane would be my Aerotowed glider. If I use all the channels possible I get to 9.

R/E/A/A/F/F/ 2 spoiler channels/tow release = 9

What's in your plane that uses more than 9?

aussiesteve

My 150cc YAK

2 x Rudder
4 x Aileron
4 x Elevator
1 x Throttle
1 x Choke


On a 14MZ TX through 2 x RX's

My 150cc Ultimate
2 x Rudder
8 x Aileron
4 x Elevator
1 x Throttle
1 x Choke



On the same Setup but some of them use the same channels

felker14

My Feedback: (50)

comp-arf flash = 1 rudder, 2 elevator, 2 aileron, 2 flap, 1 nose wheel, 1 brake, 1 retract, and 1 throttle

s3nfo

My Feedback: (14)

Bobcat - 1 elev, 2 rudder, 2 flap, 2 ail, 1 nose wheel, 1 brake, 1 retract, 1 throttle (ECU).

A7 - 2 elev, 1 rudder, 2 flap, 2 ail, 1 nose wheel, 1 brake, 1 retract, 2 throttle (older turbine requires seperate (mixed) kill). Would like to have one or 2 more for drop tanks/bombs.

aeajr

My Feedback: (2)

Thanks to all who responded. I will ask based on Steve's but it really applies to all of them.

2 Rudder? Why not a Y cable? They need to work together, right?

8 Aileron? I presume you have 2 ailerons with 4 servos each. If so, why would they not be on a common harness on the same channel? I would think sequence lag would cause them all to move at slightly different times causing the the 4 on the same surface to work against each other.

Forgive my ignorance, but I don't fly planes in the class of what you seem to be flying, so I am interested. I can see 2 channels for ailerons, but 8?

That 150C ultimate calls for a 16 channel radio, if I understand your post. Yet the 14MZ only has 14. Remember the question is about channels, not how many servos you have.

Also, how do you do this through 2 receivers?

aviti

My Feedback: (54)

A Y cable will not allow you to match servos so 2 ganged on rudder will fight. What if you want 3 on rudder? A 3 way Y cable? Matchboxes have been a solution for this but I prefer to avoid another point of failure when possible. The newer high end radios are becoming easier and easier to set up a plane with 12+ servos.

TLH101

My Feedback: (90)

Add to those already mentioned, scale functions like bomb drops, lights, drag/air brakes, sliding canopies, smoke systems, drag chutes etc. If there is a channel left, a scale guy will use it for something. Also servo contolled chokes or kill switches on gas engines, and inflight mixture control on ducted fan types.

rmh

Having assembed some all glass 40% stuf - I see why guys like 14 channels

a lot of it has to do with the goofy aileron setups whre the linkage and servo positions don't permit identical servo/linkage at 3 points
(these were done for others -I don't have any myself) but for any powered aerobatic model - 5 channels of info, pretty well covers all the bases
this info , distributed to a good power system ,will work -
If the model needs a bunch of servo matching - due to linkage design - well then go for more channels
personally one rx and 5 channels is all I see as required - I can manually match servos .
on a 40%.
dun it

Red B.

I don't know if receivers like the ACT Diversity systems are available in the U.S. but they are a very good solution for big aircraft with the need for a lot of servos. Two 10-ch receivers can be linked together, providing 2*10 = 20 channels output. The great thing is that the receivers are programmable. Each transmitter function, i.e., ailerons, rudder, elevators..., can be linked to one or more of the 20 outputs of the receivers. Each servo output has its own servo reverse, end-point, sub-trim and fail-safe adjustments. Additionally, for each of the 20 servo outputs, up to 4 free mixers are available. This means that each Rx output will accept inputs from up to 4 transmitter channels in varying amounts depending on what mixing ratios are used.



For an IMAC-style aircraft with 6 aileron servos, 4 elevator servos, 4 rudder servos, smoke and throttle one could choose to send the aileron signal to Rx outputs 1-6, the elevator signal to Rx outputs 7-10, the rudder sigbnal to outputs 11-14, smoke to output 15 and throttle to output 16. Sub-trim and end-point adjustments in the receivers would be used to match servos. As for the transmitter, any 5-channel transmitter would suffice.

tranker

My Feedback: (1)

Larger Warbirds tend to require more channels or servo matching components.
Seperate servos for retracts, flaps, elevators, rudder, tailwheel, choke, throttle, etc....

Ron101

My Feedback: (22)

"Also, how do you do this through 2 receivers?"

I have not done this myself, but this is my understanding of it from talking with guys at the field.
You would use two RX on the same channel. One would control everything on the right side (R Aileron, R Elevator half so on)
the other would work the Left side. You get more open channels to work with for many servos. Plus you have a battery for each side which give you a back up Batt. and switch plus not so much load on one RX. Also if you lose a RX you can still fly the plane useing one side.
I've been told the plane will fly fine with just one side... good enough to get down in one piece.
thats just my understanding could be a bit off

Ron

Darkbird

My Feedback: (7)

Another thing that no one has mentioned would be seperate channels for engines on multi engine planes. Would allow for easier syncing of the engines and differential thrust mixed with rudder.

aeajr

My Feedback: (2)

Wow, now that IS interesting. Sounds simple enough to set-up. I like the redundancy factor to protect you against either receiver path going out. If you mix ailerons to flaps, then if you lost an aileron, the flap on that side would help to fly the plane. Awesome!


Red B.

That ACT system is even cooler. In that case 1 channel can handle multiple servos and you can tune each one individually from the receiver. Very very cool. But it must cost a fortune! But I guess in this kind of application, it is worth it.

Red B.

It gets even better. Using a twin frequency Tx module the ACT Rx is capable of receiving on two frequencies simultaneously(!). Using digital signal processing the Rx is programmed to select the strongest signal that contains valid information, rejecting signals with interference. For monitoring purposes the Rx contains a data logger that records the signal strength and Rx voltage.

As for power supply, the Rx can handle anything from 4-7 NiCd or NimH batteries or 2s LiPo batteries. Because the Rx uses Multiplex high current connectors the Rx is capable of handling servo current up to 15 A in total, thus in most cases eliminating the need for "powerbox" systems.

I bought a couple of receivers last years and have not yet exploited all the possibilities they offer :-)

Here is a manual (in German): [link=http://www.acteurope.de/Handbuch5neu.pdf]Rx manual (PDF)[/link]

aussiesteve

OK Then. Here's my reasons for doing what I have done.
Y cables are a common source of failure. In a plane of this size, equipment Failure is not an option. The planes are expensive, the danger levels in the case of a failure are very high and in competition (IMAC in this case) You lose too many points for lack of precision (Even though the plane flies better than I can anyway - At least the only limiting factor is me).

As Aviti mentioned, Separate Channels allow for proper servo matching.
I use multiple servos on the control surfaces because it is often lighter and cheaper, but definitely more accurate to get the torque required from 2 smaller servos than one large one. Also the current draw through a single large servo can be quite high which requires the use of a bunch more electronic components that are a potential source of failure.

Now to contradict myself a little
On the Ultimate, I do have some servos "Y'd" together via JR Matchboxes. I had no choice but to do this Because The radio only has 14 channels.

For the two receiver Question. I use two receivers so that there is some redundancy. I use one for RHS and one for LHS as Ron101 has mentioned. I have also recently trialled the Powerbox Redundant Receiver System but it is limited in Channels at the moment. I have heard of the ACT Diversity units but have yet to experience them.

In Summary - I prefer to use separate channels for each servo as it allows more fine tuning of the servo, More current available for the servo and redundancy in the event of a failure of a single item.

I actually considered the idea of turbo-propping the Ultimate (To turn it into a Toucan) but that required even more channels to allow for the starting sequence.

causeitflies

F-16:
2 tailerons
1 rudder
1 steering
1 throttle
2 retracts/doors
1 brake
1 smoke
Ailerons are optional on this one and that would be two more.

ww2birds

My Feedback: (14)

Typical large warbird with my 14MZ (this is the "luxury" approach exploiting lots of channels to make setup fast+easy, and usage flexible):

4 on Wing: 1 channel each for Left Flap, Right Flap, Left Ail, Right Ail ... could use harnesses or MSA/Matchboxes, but 4 ch is really easy for setup, allows ail diff, allows flap travel to be trimmed independently even in flight to eliminate any roll coupling from full flap deployment. I use a 3-pos switch so I get three repeatable settings: no flap, 15 degrees and about 45 degrees. Typically mix from flap to elevator so that I get 3-5% down elevator with full flap ... but that is airplane dependant. Could also use a flight mode for this. Flap operation uses slowed-down motion .. 1-2 secs for full travel.

4 on Tail: 1 channel for rudder, 1 channel for tailwheel, one for each elevator half .. use the "jet guys" setup on tailwheel .. with separate tailwheel servo. The primary control for rudder is left stick, primary control for tail wheel is one of the rotary knobs. Mix rudder to tailwheel at low rate (on all the time) , second mix rudder to tailwheel that turns on below 1/4 throttle. Allows full taiwheel travel on taxi, tones down tailwheel travel on takeoff roll. Allows taxi direction to be trimmed by using knob .. really easy while taxiing .. then snap knob into down position.

2 on motor: 1 for throttle, 1 for choke (set choke to work on trainer momentary switch .. can usually keep engine running when starting .. flip till coughs while holding trainer switch .. let go and she stays running). Also gives a second kill option (in addition to low throttle)

1 on retracts

--- end of "core" ----

--- optional ---

1 for smoke system (if used .. typically left hand slider on bottom of case .. easy to reach while flying)
1 on gyro gain (if used, typically on rudder)
1 on brakes (some warbirds, most jets .. typically right hand slider on bottom of case .. )


So this gives 11 channels for "core" with three options. Oh, and there might be ordinance drops, operating canopies and speedbrakes .. yikes .. good thing Futaba has the channel expanders :-)


Dave McQ