FASST VS XPS

[tppjr]

Any inputs??

Thanks,

Thomas

[tppjr]

Over 100 views and nobody has any information?

Thomas

[capebob]

Over 100 views and nobody has any information

Yep, that just about says it all.

Bob

[Motions]

XPS is already available. Does that help?

[tppjr]

I guess my biggest concern is if the Faast system will slow down my already SLOW 9C even more? I know the XPS does. Trying to decide to wait for the Futabe system of ditch it all and go with a DX7?

Thomas

[Motions]

How does the XPS slow down your 9C? I use the 9C with XPS and mine is much faster now.

[tppjr]

Don't remember where but do remember seeing a amount (ms) of latency that XPS would add. I will see if I can find it again.

Thomas

[Bastian1337]

Do you guys really think the average pilot will be able to notice if a 9C is slower than a DX7? I kind of doubt that.

[Motions]

Originally Posted by Bastian1337

Do you guys really think the average pilot will be able to notice if a 9C is slower than a DX7? I kind of doubt that.

I know for a fact they can't tell the difference. It's all mind games. If you tell someone it's faster, they expect it to be and they're mind says " It IS faster".

[tppjr]

Originally Posted by Motions

I know for a fact they can't tell the difference. It's all mind games. If you tell someone it's faster, they expect it to be and they're mind says " It IS faster".

But didn't you just say that yours was much faster now with the XPS?

Thomas

[Motions]

Yes. I had to lower the gain on my gyro 5% and I have a slightly batter feel for the model. If you just threw it in my hands without telling me what it was, I probably wouldn't notice, like anyone else.

I know for sure it's not slower though, that's a fact of numbers there.

[kgfly]

Detailed latency info is available here (first post is updated whenever new data becomes available): http://www.runryder.com/helicopter/t172571p1

A few facts to ponder:

* To use XPS (or Spektrum) module in any radio you have to set the radio to PPM (not PCM) mode. PPM mode is always faster than PCM so you gain right there.

* Futaba 6ex/7c/9c/9z all have CCPM mixing software that introduces a lot of latency and slew-rate limiting on the CCPM channels. This tends to swamp all the contributions to overall performance. For example for CCPM operation the 9c has 84ms latency in PCM mode versus 65ms in PPM. This compares to 36/24 for a JR 9303 or 27ms for a DX7(DSM2) or 34ms for a T6EX(FASST).

* The first generation XPS was shown to add from 22 to 44ms on a JR9303/PPM setup making it average 60ms, still ahead of the 9c on its best day.

* XPS have updated firmware that they say produces significantly faster performance due to a bug fix (should eliminate the rolling from 22 to 44 down to no more than 22) and a feature similar to Spektrum ServoSynch that makes the CCPM channel outputs at the Rx synchronous. This update is not yet shipping AFAIK.

* The ability to perceive differences in latency varies from pilot to pilot. However, we are generally able to compensate for fixed latency but we are very sensitive to variations in latency and so the wide latency range for the Futaba solutions makes them even worse than their average latency values suggest. While it is undoubtadly true that there is a psychological aspect/placebo affect when someone gets a new toy, experienced pilots flying familiar models repeatedly describe how well practised manouvres are off when switching to a lower latency solution (like the DX7 or in some cases, XPS) and that they have to adjust their control timing to compensate for less lag. So it seems lower latency and certainly more consistant latency, can really make a difference to flight feel and performance. Small differences between systems (say under 20ms) are probably not too important so long as variability is similar.

Based on the above the odds are that an XPS module with the new firmware will probably be faster in your 9c than your existing FM solution but the wide variability and limited slew rate, which are a function of the 9c CCPM mixing, will remain.

If you really love the features/programming of the 9c then go ahead and get an XPS solution for it, I bet you will be happy. If you are not wedded to the 9c and can afford it, change to a DX7, 9303+XPS or the new X9303/2.4 or 12X/2.4 which will almost certainly deliver blazing performance equal to or better than the FM 9303 does today.

[kgfly]

Late breaking news...this comment was posted here today about flying a 9303 after swapping from FM to XPS:

Originally Posted by ErichF

The connection felt great, although I did have to get used to the different feel for my precision work. It was a solid link, though, even when doing far out turn-around manuevers typical of FAi flying.

I just noticed that 9303+Spektrum has been added to the results:

Tx               Rx        Min    Max    Avg
--------------  --------  -----  -----  -----
JR 9303         770S       15     47     36.3
JR 9303/Spektr  AR9000     40     68.3   54.4
JR 9303/XPS     XPS 8-ch   33     81     60
--------------  --------  -----  -----  -----
Prediction for XPS with FW upgrade:
JR 9303/XPS     XPS 8-ch   33     49     40
--------------  --------  -----  -----  -----

What is intriguing is that according to the JKOS measurements, the latency for Erich went from a range of 15-47 (avg 37) to 33-81 (avg 60). So both the variability and average have increased but it felt better to the pilot Maybe this is evidence of placebo but he is a precision pilot so I doubt it. It is also possible that the JKOS tests don't represent real world usage : JKOS documents his test setup and it seems to make sense to me, I guess you will have to decide for yourself

[DavidH]

It is also possible that the JKOS tests don't represent real world usage

Tbat has been the key to this all along the way. Real world vs. test scope is totally different. Can write numbers on paper all day. That doesn't mean it is actually going to work that way when being used by people in the real world everyday.

David

[heliboy88]

Is it possible to use expo to at least compensate the feel of that latency around mid stick? I just got my 9CS months ago and i love this radio, really don't want to give it up for a dedicated 2.4G radio, but still thinking of going the 2.4 module route. Any advice?

Best regards,
Rich

[Nankin Hobby]

I have a 9C Super and the XPS module i picked up at Toledo. I am a huge fan of XPS and have been since day one. I love the 9C programming ease and the reliability of the XPS system (best 2.4 i have used to date) I do not however like the Eccpm of the 9C. It blows in my T-Rex 600 and it is noticeable even when i let a novice fly it. Its my favorite radio with the XPS in it as long as you are not doing Eccpm helicopters. Even with this so call chip upgrade futaba supposedly did before the 9C Super hit the shelfs, it still sucks. If you happen to be/are going into Eccpm helis, then look at the 9303 or DX7, you will be glad you did.

[Skiddz]

I've been flying a 9C for the past year or so (both planks and helis) and just got a DX7 and swapped over one heli. I don't really feel a difference in how the heli flies and the "feel" of the Tx in my hand is "odd" compared to the 9C - I guess it feels "cheesy" since the mass is a bit less than the 9C.

Programming wise, the DX7 is cake, but I prefer the 9C's interface. I'm not sure if I'm going to hold on to either radio when the 12FG comes out or opt for an XPS or FASST module. I guess I'll have to see what's out there in a few months and decide then.

[Nankin Hobby]

I will have a 12FG in the shop tomorrow...gunna have to do a little testing on that bad boy. A Futaba rep told me today that the programming is based of the 12MZ but it is different. (coding) I couldn't get a direct answer to how much of the hardware in the 12FG is the same as the 12MZ. Knowing Futaba i cant imagine they would redesign the hardware completely that soon after the 12MZ release. Has anyone head anything else on it?

[heliboy88]

Hi Nankin Hobby and Skiddz,

Thanks a lot for the heads up, i'm and will be flying eccpm helis, so i think i better get a dedicated 2.4 radio then. And i saw the 2.4 futaba 7C somewhere, so i think i'll wait a while til it comes out before i decide on anything.

Best regards,
Rich

[kgfly]

Rich - The Futaba 7c (and 9c/9z for that matter) have very poor eCCPM performance compared to almost every other radio currently available: http://www.runryder.com/helicopter/g...y_pcm8_avg.gif

I don't know why one would choose an F7c over a DX7 particularly if 2.4GHz is an important part of the solution