FrSky Tx/Rx behaviour in the air?

Problems, experiences or just something to say about RC gear? Say it here.

FrSky Tx/Rx behaviour in the air?

Postby pldb64 » Sun Feb 19, 2012 2:26 am

Hi All,

I have my AXN setup with the FrSky DHT DIY module and i'm flying it with a D4FR receiver. It's now clocked up a whopping great 7 flights :-) ... you gotta start somewhere right!

I had an interesting experience during the last flight today and wanted to get people's feedback as to what the possible cause might have been.

Note - to this point, 6 flights with perfect responsiveness - no issues whatsoever other than needing to get use to the sensitivity of the model/settings.

Flight 7 - take off all ok into a slight breeze (~2-3km/h) then about 20 seconds into the flight the plane rolled sharply left and pitched down without any input from me. I was approximately 200m from the plane at the time and no audible warning to indicate that i was approaching FrSky receiver limits. (BTW - i had down a power down range test and confirmed that audible warning were operational). From my PoV, it appeared to loose control momentarily. Fortunately i was able to gather everything up pretty quickly (2-3 seconds of heart palpations) and carry on flying. No further loss of control. Instructor nearly had heart failure as well :-)

So my question to this learned forum is whether or not this is something others have seen as well? Is it a symptom of 2.4Ghz interference at play or was it more likely a sharp wind gust that took over for a second?

If it was interference, i would have thought that i would continue to see bad behaviour? Would the FrSky reset the portions of the band it was using to communicate or could it be something else?

I'm really interested in any suggestions that its a faulty setup on my part so i can eliminate the problem.

Any suggestions as to how to confirm my setup is NOT the issue would be greatly appreciated.

Thanks
Peter
Turnigy 9x, FrSky 2-Way/Telemetry DHT DIY, Smartieparts BRD, ER9x FW
AXN-Floater (stock esc, motor & prop, HK orange 9g servos)
pldb64
 
Posts: 156
Joined: Fri Nov 04, 2011 3:09 am
Location: Sydney, australia

Re: FrSky Tx/Rx behaviour in the air?

Postby RCModelReviews » Sun Feb 19, 2012 6:31 am

Unlike the old AM and FM systems associated with long-wire, 2.4GHz systems don't respond to interference by "glitching".

When the data is sent across the 2.4GHz system it has accompanying checksums that verify the received data is what was sent -- and if the checksums indicate that the data has been corrupted then it's simply ignored.

So, what happens in a case of interference is that control either becomes very sluggish or the system simply stops responding and (after half a second or so) goes into failsafe.

If your plane dropped a wing and turned unexpectedly then you may have had a tip-stall. This can happen with the AXN if you're flying very slowly -- they will drop a wing and turn sharply. The answer is to simply fly more often and learn to recognize when the model is close to the stall. Sometimes, when I'm doing my "low and slow" flying, I still get caught out by a tip-stall because I'm "on the ragged edge". Fortunately, because it's an AXN, you just pick it up, throw it and keep on flying ;-)
RCModelReviews.com, just the facts.
User avatar
RCModelReviews
 
Posts: 2120
Joined: Tue May 04, 2010 3:40 am

Re: FrSky Tx/Rx behaviour in the air?

Postby pldb64 » Sun Feb 19, 2012 7:44 am

Hi Bruce,

Thanks for the explanation of 2.4GHz behaviour - just what i was hoping for.

I'll certainly err on the side of accepting the tip-stall explanation. Much rather explain it away with newbie piloting rather than a radio issue. I'll be sure to report back again if i see anything that doesn't fit with the explanations provided.

Thanks
Peter
Turnigy 9x, FrSky 2-Way/Telemetry DHT DIY, Smartieparts BRD, ER9x FW
AXN-Floater (stock esc, motor & prop, HK orange 9g servos)
pldb64
 
Posts: 156
Joined: Fri Nov 04, 2011 3:09 am
Location: Sydney, australia


Return to Radios and Servos

Who is online

Users browsing this forum: No registered users and 3 guests

cron