ChixwithTrix

My Feedback: (8)

If you have 4 aileron servos, 2 on each wing, and you y connect the 2 servos on each side. Could you y connect the already y connected aileron servos so all 4 of them would come together and go into one slot in the reciever, instead of 2 and having to mix the 2 channels?

bob_nj

My Feedback: (62)

I'm sure you will see some interesting and informative replies. It is possible though. What size plane and how many servos total?
Are they analog or digital? So many questions...

ChixwithTrix

My Feedback: (8)

they may be jr 8411's digital(8) or hitec 5735mg digital(8)
the plane will be a h-9 33% cap. which servos woul u use?

bob_nj

My Feedback: (62)

http://www.rcuniverse.com/showthread...086&forumid=38

I asked a similar question earlier. It has no responses yet but I'm hoping Mr. Glavin gets a hold of it. He's the bomb on this stuff I am using 8411's. One of my concerns is how in the world to match the aileron and elevator servos using the linkage only. I put seven 8411's on the bench and built a degree wheel of sorts to get the real poop on the neutrals and endpoints. They weren't even close. I used a JR Matchbox to set up the three servo setup on my rudder and I got it perfect. I used a milliampmeter to verify and am only drawing idle currents at neutral and the ends. This is my first hand at setting up a large multi servo plane. Man am I getting an education :

ChixwithTrix

My Feedback: (8)

well...is it easier to just y it once and mix the 2 channels for the ailerons?
yea this is my ist giant scale plane to have to build, and im not even building it yet, just gathering info

bob_nj

My Feedback: (62)

When using digitals, it's not so much the mixes, but the linkages and total throw that gets you. One of the outstanding features of the digital servo is its tremendous centering ability and holding power. In a perfect world when you link several servos together and all centers are equal life is good. What actually happens is that the neutrals are slightly off and the fight begins. Each servo wants to hold its current position in a big way. Same thing happens at the extremes. Result -> Amp draw goes out of sight.
Battery time decreases and strains are put on gears and linkages that cause abnormal wear and tear. Anyway, what I and you need to do is adjust the geometry and linkage on each two servo aileron so there is no buzzing at neutral or full throw. Better to use a milliampmeter. Whew, that was easy

mglavin

My Feedback: (31)

First thing I gotta ask is about the name ChixwithTrix?

Now to the task at hand:

Yes you could do this but it will be nightmare with servo reversing, high current draw, centering, ATV's and such. I strongly advise you do something else.

The H9 Cap ARF manual is very informative on these issues and provides a required component list and if I recall offers programming ideas for various radio system.

I would use one HD 22 gage Wye per wing. Use the aileron differential mix, flaperon mix or create your own p-mix. I like to have the Wye's custom built, the length is tailored to you needs eleimanates additional extensions and connections. These wyes cost about the same as an off the shelf wye, and when consider you are eliminating additionally extensions to reach the servos and RX you actually save money and end up wiring system that has chance of failure due to the reduced connector count, additionally you have less electrical/wire/connector resistance which is a huge plus...

The servo matching anomaly is less of an issue with aileron and elevators due the space between the surfaces, since there not right next to each other so you get by with the mechanical adjustment generally. However there still maybe ATV issues, the centering issue is usually absorbed by the space/distance between the servos as mentioned previously. The milliamp meter is an excellent method of setting up these types of ganged servos.

Alternatively the HiTec servos and programmer work great.... There are other companies that offer devices such as the JR Matchbox that are limited to two servos and I believe they are about half the cost.

EMS-Jomar can and will provide custom Wye's and they also offer a unit as mentioned above.

bob_nj

My Feedback: (62)

I'm not sure I completely understood the two channel statement. My understanding is that it is for a single receiver channel and up to four servos. Each servo having its own center, reverse, and endpoint adjustments. Thanks_bob

Steve Collins

My Feedback: (8)

It sounds like the JR Matchbox is exactly what you need. Go here for a detailed review of the Matchbox and decide for yourself:

http://www.jetpilots.org/JR_mathcbox.htm

mglavin

My Feedback: (31)

Bob

I meant to say two servos, not two channels. As you recognized. :stupid:

Others are offering a device similar to the Matchbox that works with two servos. These devices actually allow you to gang three servos. The master is controlled by the TX for centering, reversing and ATV while the slaves are programmed individually. Same idea and concept.

HarryC

My Feedback: (1)

If you are building that sort of model with expensive servos, haven't you got a decent computer Tx that can handle 4 aileron servos on 4 separate channels? You only need 7 channels for a 4 function model with 4 aileron servos so it's not a demanding task. Then you adjust each channel separately at the Tx to equalise the travel of each servo.

Harry

bob_nj

My Feedback: (62)

Let's use say an Aeroworks 33% Edge 540T as an example. Dual aileron, elevator servos per half and one big baby on the rudder, one throttle. 10 servos, 10channels. On many computer radios each of the 10 channels will have its own center(sub-trim), reverse, speed, and end point adjustments. Mix RH aileron with aux2, LH aileron/flap with aux1, LH Elevator with aux4 and RH Elevator is aux3 with aux5. Use p mixes to get them together. Will it work? Sounds like a ton of long wires but they don't seem to be a huge issue if done properly.

Let's also consider this. Theoretically couldn't you run a siimilar scenario on a larger model by "Y"ing the ailerons and elevators and gang 3 rudder servos on seperate channels in the transmitter mixing.
As mglavin pointed out to me, when servos are not ganged and close to one another as on a rudder, the linkage adjustment and current drain is easier to get to a minimum because of the distances apart as on ailerons and elevatos. This becomes especially important when using digitals. Go here ->
http://www.rcuniverse.com/showthread...145&forumid=27

While we're at it, there is a related thread here ->
http://www.rcuniverse.com/showthread...086&forumid=38
Guess we might as well get it all done at once )

HarryC

My Feedback: (1)

I only count 8 channels if using 4 aileron, 2 elevator, 1 rudder and 1 throttle? On my Tx this takes less than 1 minute to set up and no mixing is required either, unless I want ele-flap and tailerons. I just assign whatever channels I want to the aileron control, if you have to mix then you have a restrictive Tx, get a better one! I can get a 9 channel Tx with user assignable channels in the UK for £250 ($350). Surely the likes of a 3810, 8U or 9C can handle 4 ailerons? Even if you have to use mixers it is still better than a Y lead. You can do all your adjusting at the Tx without buying and adding another component (I have never heard of a JR matchbox but if you need something like that you need a better TX) If something goes wrong with a Y lead you lose 2 servos, if you use separate channels and something goes wrong with a lead you lose one servo, plus the single bit of the Y lead is having to carry the curent for 2 servos. Whether you use 4 channels, or 1 channel with Y leads, you still have stacks of wiring, it makes no real difference. I fly 4 servo wings using 4 separate channels, no mixing, with a ferrite ring at the rx end of the wires to block any RF signals.