Aerohead

My Feedback: (37)

Okay, all you guys out there that have the Futaba 9C know that when you mix two channels together, for instance channels 2 & 8 for dual elevator servos, there is a slight lag on one of the servos, so these servos are not perfectly matched. Does anyone out there know if the new 9C Super fixes this lag time? I thought that I had read that somewhere, but I'm not sure. I wouldn't mind upgrading to the 9C Super if this problem has been solved for sure, but I'd be pretty pissed off if I paid the money for the Super and got the same exact problem. Also, does anybody know what the actual upgrades are with the super, other than more model memories? On all the Futaba ads, all they do is list the characteristics of the Super, not the actual improvements over the 9C. If the 9C Super does not fix the time-lag problem, is there a radio out there that does, other than the ridiculously high-priced 14Z?

Bax

My Feedback: (11)

Short of operating the two servos off of one channel with a 'Y' harness or servo synchronizer, the slight variance between two channels operating elevator halves cannot be eliminated. Even the 14MZ does not totally eliminate it, but because the two channels used are adjacent in the counting order, the effect is greatly reduced, especially with the slightly higher processing speed of the MZ.

The features of the Futaba 9C Super can be found at:

http://www.futaba-rc.com/radios/futk75.html

iflyj3

My Feedback: (7)

With the difference of about 9 milliseconds between channels 2 and 8 I find it hard to believe any one can detect the difference when flying the plane. It would take a lab setup to measure the difference.

Josey Wales

My Feedback: (61)

When using normal sport-flying rates it isnt that big of a deal..when you goto 3d rates( 45-70 )deg it is very noticeable. You can get them pretty close by adjusting the linkages but not exact.

Geistware

My Feedback: (16)

I have dealt with this back with the 8U.
For precision flying, it doesn't have much of an effect.
I don't know about 3D but from the above post, it does make a difference.
Also the way that data is sent to the RX from the TX is not sequential.
Futaba does something that others can better define.

jayjayneri

The solution to dual elevator servos on the 9C is not to mix 2 channels together but to use the Ailevator function. I think you use channels 2 and 8 with this. then all you have to do is set the aileron travel rate to 0 on the ailevators menu and you are set. Try it.

Josey Wales

My Feedback: (61)

I dont think the problem is getting them to both move in the same direction..the issue is that there is a slight delay between the 2 channels causing 1 servo to lag behind the other...like Bax stated above, the 14MZ uses 2 channels right next to each other instead of 5 channels apart reducing the lag.

3D Joy

I use ailevator functio and I can actually see lag between the 2 elevators. Never feeled it was a big concern though. It does not show in my flying.

Bax

My Feedback: (11)

Actually, for any R/C transmitter, the information is sequential. It can't be helped. The processing is digital, which means the processor can only do things in a sequential manner. Seamless operation is achieved through higher processing speeds. The transmitter reads the postion of stick #1, then stick #2, and so on through the channels. They are each processed in order. If you have two channels that are mixed, then the mixing is processed after the second channel is read. The resulting position information is then sent to the receiver.

For all systems, the channels are most definitely sent out in a defined order. The only difference between PPM and PCM transmissions is how the position information is coded. For PPM, the duration of a pulse dictates the position. For PCM, an 8-12 bit string describes the position. The information is still sent out sequentially. It cannot be otherwise.

To make things move in a more simultaneous manner, the time interval between them must be shortened, as well as having the overall speed of the total information group increased. This takes up bandwidth. More speed = more bandwidth. Because bandwidth is very limited in the current R/C environment, systems are about as fast as is possible. Bandwidth cannot be increased because it's strictly-defined by the FCC.

Even the fastest computers process things sequentially. It's just that they can do it so fast that we don't notice it. "Parallel" processors still operate in a sequential manner....you just have two centers of sequential processing instead of one.

mglavin

My Feedback: (31)

FWIW: Variables in model construction, hardware installation, linkage, servos and TX programming greatly affect the ability of the two independent channels/surfaces from working/responding together simultaneously. The software frame rate lag mentioned previously in not as BIG an issue as the model specific set-up.

Food for thought:

If you have sub-trim/trim involved you've created an offset in the servo EPA/ATV travel volumes which now co-exists in MIXes, this contributes greatly.

Unequal travel arcs, disproportionate control arm pivot lengths, control arms that are not perpendicular to the surface, different thickness surfaces and varying hinge line centers of the surface and servo arm angle are all suspect.

One can make HUGE improvements by matching servo angle travel arcs and control surface travel to same. In fact if the model is properly set-up you’ll not likely note the TX frame rate lag channel to channel shortcomings..

YakPak

Guys,
Anybody out there have a Futaba 9 Channel super PPM. I am thinking about buying one and would like to know the thoughts of flyers that use them.
Thanks
YakPak

3D Joy

I have one. You can also ask those that use the PCM version, it is the same radio but with a PCM receiver. I never noticed any difference in flying a PCM vs an FM receiver...

Anyway, the radio is nice. I fly competition IMAC and I like the features like multi point programmable mixes. I especially like the fact that you can lower dual rates to less than 30% like I was stuck with on my 8UAP. Elevator IMAC rates are less than 30% of the 3D rates so it can be done with the 9C.

If I had more money, I would purchase something that has flight conditions. I will live without them for the next few years, thats for sure.

jayjayneri

Get the 12Z. Great radio!!!!!!

3D Joy

About 3 times more expensive... Its like going to the car dealer, ask for a Ford Escape and get told that a Hummer would better suit my needs...

Flyfalcons

I don't use the ailevator function for this reason. The difference is visually noticeable, though I have not tried it in flight. When setting up two elevator servos I put the second servo on channel 5. Lag is significantly reduced when using channel 5. Pretty simple work-around for those who can't live with the lag of the standard ailevator function.

3D Joy

You use a simple P-Mix for that?

pilott34

I have a 9Z. I was range checking my plane this past weekend. When in close, you cant tell the difference between the control surfaces, when you get towards the outer edge of the range, the lag is VERY obvious. The weird thing is that the ailerons which are also on separate channels dont have any lag that I can tell. Im getting around 40 paces of range without lag with the antenna collapsed. As soon as I take another 3-4 paces...the lag returns.

So what I am getting from this thread is that I should try switching the slave elevator servo to channel 5??

Mike

Zeeb

My Feedback: (41)

Well this thread is for the 9C, but I'll answer your question by saying that the default channel for the second elevator servo on the 9Z is channel 5, so I changed all my models I'd been flying with my 9C to that configuration and reprogrammed the 9C to work with it that way.

Also, the manual on the 9Z states that the first or largest diameter section of the antenna should be extended for range checks or programming the radio if it is transmitting (the 9Z can be turned on without transmitting) since it's antenna is gimbal mounted that action is what puts the antenna in contact with the RF out circuit...

edit info:
Actually I need to re-phrase that antenna information as I'm not 100% sure I saw that in the manual. But I am 100% sure it's on the FAQ for the 9Z on Futaba's website.

juanes1969

Guys, I fly a 8UAPS in my YAK 54, I have 60 deg. of movement on the elevators and even in 3D it does not show any lag in the two servos. Could it be that there are some systems that show more lag than others?
The geometry in my set up is pactically the same on both sides, maybe that is a reason for not having lag on the two servos, or reducing it to almost no lag. I am using the elevator fuction on the 8UAPS, channels 2 and 8. and even if you stand behind the plane, most (or any) of the modelers in my field, can´t see any lag on the elevators.
The 3D´s very well, and if there is lag (which I´m assuming by now there should be) it´s not a noticeable problem.
Just my 2 cents.
John

Bax

My Feedback: (11)

Servo-to-control surface geometry is VERY important in model setups. With systems that have throw and sub-trim adjustments, you should set the throw to 100% and the sub-trims to zero. Get the control surfaces set up as closely as possible by getting the geometry right first. If that's not done, then alterations in throws and sub-trims can greatly affect what happens when you add any kind of mixing or rate adjustment.

Geistware

My Feedback: (16)

I have one and while the delay is obvious, the geometery of my setup is correct so the halves stop in the same place.
It is only out of sink when moving.

dirtybird

My Feedback: (5)

The easy way to fix this is just get a pair of servos that you can reverse. Then you can reverse one and use a Y harness.

NdFrSpeed

My Feedback: (1)

Use 2 and 7,,you'll see very little lag time


NdFrSpeed