View Full Version : 1024 versus 2048

05-02-2005, 11:29 AM
at torchs, markus showed us how the resolution makes a difference by pulling the cyclic all the way down and let it snap forward.
you could see all the vibration before it came to a complete stand still in his swashblate.
now, this started a debate about if it really would matter.

it clearly is a difference in theory, since we now transmit the information on where the servo has to go at twice the speed, but what does that mean for the pilot?

as an example, if I hover a heli and I push the cyclic from mid stick to all the way right and then all the way left, then after this input has been transmitted, now the servo needs to move the linkages and then the change in angle of attack in your flybar has to move the mass of the heli.
all this should mean that there is a limit on where you would feel a difference in the transmission speed and the assumption would be that that was achieved with the 1024 resolution.

the once who have this radio, if the setup and electronic in your heli stays the exact same and you only replace the receiver and transmitter, did you experience any difference in how the heli flies now?
please explain exactly what you experience.

05-02-2005, 04:57 PM
The machine feels quite a bit different in flight. The 2048 and faster update is definitely more real time in feel and a lot of things that I noticed before where caused by the slower systems. For a lot of pilots the difference may not mean much and may or may not be that noticeable. But for a lot of pilots it is very apparent.

That stick trick that Marcus showed you will tell you one thing for sure. Try that on any other radio and you will see the lag, and lack of response. I can demo the same thing in the air. Move the stick fast in the air and the hei will respond on the 14MZ. Do it with another radio and you will get a wobble, but not near the same response.

Probably even more noticeable is when you setup an ECCPM heli. You will find that 90% of the issues we saw that where attributed to servo's and or linkages where actually caused by the radio and its update speed. Even without adjusting the swash detail menu my swashplates where much more true than what I was able to achieve in the past.

Anyway, just some things to think about. The radio may not be for everybody due to the price, but if the price where not the issue I believe you would see most people flying this radio. Probably even more of a reality check is to fly the radio a while then go back and fly something else....... Then you really notice the difference. I am sure others will comment.

take it easy :D

05-02-2005, 05:01 PM
thanks for your input eric.
anyone else?

Russ McC
05-02-2005, 05:49 PM
Hi Data,

Second every thing Eric said! It is interesting that these servos (9252) are rated at a given speed but with the 14MZ-G3 they are faster, so the old systems update speed was apparently slower then the servos rated speed.

The combination of the faster update speed and the increased resolution are very noticeable and even make some maneuvers easier, where quick well timed cyclic inputs are required. Also my swash runs true, very very true. These are the reasons this radio is worth the money! The easy programming and cool features are just the frosting :glasses2:

05-03-2005, 11:35 AM
The trick Markus showed you is not really demonstrating higher resolution but more importantly the 40 percent faster data rate from the tx to the rx. You only need three positions in your example, mid, full right and left. The performance in this radio comes in timing and in precise flying.

You really need to fly the 14MZ to feel the big difference it has over the 9Z. Itís more than the 2048 resolution but also the 40 percent increase in response that makes it a better radio. The speed of the digital servos is now being utilized by the 14mz. Here are some first flight observations from my trip to Birmingham, Alabama, this year.

Control inputs are faster and more precise, resulting in the pilot not having to move the sticks as much. As I fly smooth and precise the amount of time I spend thinking of making corrections is far less than before. Now when I do make a correction I don't need to move the stick as much as the model is commanded sooner and faster. Again, less stick corrections as the faster datalink and servo speed keep up with the slightest corrections. I'm now just putting in very little inputs to keep the model were I want and spending more time thinking about where I want to go and what's next. I'm also flying more comfortable down low as the speed of my commands and corrections by the model are so fast that I know I can get out of trouble quicker.

With the 9z the model would move out of position even if I gave some small correction. In the pitch and throttle (especially while hovering) it was like my corrections were two steps behind. Thatís gone with the 14mz. Also, I used a lot of - expo as the fast digital servos we really not helping my flying and I had to reduce their affect to help with my control timing, especially during hovering. My commands would be behind what was needed and I would get in situations where I needed to wait to see if my inputs would take affect. This mental delay resulted in slower flying /corrections on my part.

On my first flight on the second day of using the 14mz at B-ham I placed the model starting position to hover sideways right in front of me. As I lifted the model to have the landing gear eye level I locked the model into a hover and tired to maintain position. I don't remember holding a model so still before and or actually giving any inputs. I just would see the model about to move and then it didn't. As the model was out of trim, wanting to fly forward, I held back elevator all the time. But once I found the stick position to hold the model I didn't think I moved the stick very much at all. I don't remember ever holding the model so stationary than with the new 14mz.

Just like the GY601 is using a high data rate from the gyro to the servo, the 9251 data speed is like 270hz, all the other flying channels (throttle, pitch, elevator, and aileron) are now keeping up with the speed of the tail servo. The 14mz is using the speed in the 9252 servos to keep the commands to a minimum and more precise. With the 14mz I had to delay my inputs while flying as they are taking affect too soon compared to the 9z.

I was doing medium speed pirouetting flips at eye level and while the heli was pirouetting I was making slight corrections to cyclic more than I could before. I was mentally and physically correcting the position of the model much faster than I could with the 9z.


Andi G
05-03-2005, 11:45 AM

> Just like the GY601 is using a high data rate from the gyro to the servo, the 9251 data speed is like 270hz, all the other flying channels (throttle, pitch, elevator, and aileron) are now keeping up with the speed of the tail servo.

that would mean you can't use analog servos on the G3 rx. Actually the G3 framerate time is 17.6ms (57Hz) according to Futaba, pcm1024 is 14ms (70Hz) and therefore a bit faster - but this times don't really matter, they are just marketing hype.

Where the 14MZ excels is the time it takes to read in the stick position and compute the new channel data. Some radios lag a lot there see the discussion on runryder (about ccpm implementations).

Another pcm1024 problem seems to be that it's differential, therefore fast changes need several frames to arrive at the rx.


05-03-2005, 01:09 PM
Futaba says it is 40% faster than the 9Z. Not sure what the #'s are based on, but that I assume is 40% faster at 2048 than the 9Z at 1024.

Despite the #'s, it sure feels faster and more precise. There is not much question there.

The radio is just another in the long list of improvements we have seen. I am glad Futaba is willing to take the risks and R&D new stuff. There still is not any gyro out there that will keep up with the GY601 and the GY401 will outperform 99% of others out there. The GY611 is right around the corner and though it is just an updated and upgraded 601 I am happy to see they are not sitting on the sidelines.

05-03-2005, 05:05 PM

"that would mean you can't use analog servos on the G3 rx"

"are now keeping up" does not mean we can't use current servos. Yes we have the same servos, shame I would have purchased faster servos with a new radio, but it turns out the digital servos were/are under utilized.

"Actually the G3 frame rate time is 17.6ms (57Hz) according to Futaba, pcm1024 is 14ms (70Hz) and therefore a bit faster - but this times don't really matter, they are just marketing hype. "

I have seen o-scope pictures where Ail, Ele, and Pitch pulses are all being sent at the same time (not sure exactly where these were taken, see RR). So grouping them improves the data throughput more than the slower frame rate numbers indicate. We need more information on the signal characterizes from start to end of the 9z us the 14mz before we can clearly indicate where the 40% improvement comes from.

I agree it looks like the implementation is done correct. Shame they didn't design it right from the start. Now were approaching the true specs with this radio, or are we?

If you ever find your way over to Maryland USA I'll let you fly my 14mz and feel the difference for yourself.