Originally Posted by
Jim.Thompson
I am interested to know what telemetry receiver(s) you are using then Bert? Also, how is the telemetry useful for "getting a good tune"? (I probably should already know this - pardon my ignorance).
The reason that I abandoned use of telemetry receivers years ago was that I had a run of FrSky telemetry receivers failing. I have a thread documenting these failures (and crashed planes), over on rcgroups. (More than one failed on the bench!).
(A flying buddy also had similar experiences and we both bought up and since use "V" series FrSky receivers. Zero problems experienced with them, and I have not read of one single failure from other flyers.)
Nothing in this regard is irretrievably locked in for me; I could now use another brand; maybe FlySky which to my knowledge, have a good reputation. Also, they produce a 10 channel rx. which would add an extra advantage as I am running out of channels on both my two stroke powered tugs; resorting to sharing one channel for two control surfaces etc. (Y leads).
So, to sum up; what Chris has provided for me will get the project moving forward, which is my primary need.
His assistance has increased my understanding of arduino basics and with some further work on my part in due course, I may be able to get a "full" sketch to verify.
I am completely open to flashing my XIAO board with the full sketch and to order another 10 channel FlySky receiver. (I have one in commission somewhere - cannot remember this morning!)
I have no legal flying field locally, so cannot fly until sometime next year - so I have plenty of time to experiment and modify etc.
The little XIAO board can be flashed (uploaded) with the limited sketch and then flashed again with the full sketch when and if I get a sketch to verify on my system.
Thanks for reading all this, I did not intend to clutter the discussion up with extraneous matters.
Jim.
I Use nowadays the X8R or XR8R (from memory, forgive me if the designations differ a bit from reality) receivers, with the in Europe compulsory "listen before talk" protocols and max 100 mW TX power, and I do not experience any issues.
Having telemetry data in itself (with which I mean, the option to read data from the display while flying) is not all that important... But what IS important and has brought good progress both in developing this solenoid stuff, as well as solving tuning issues, is the data-logging option, which allows to represent each flight in graphs.
In order to utilize this, it is necessary to fly test-protocols (a predetermined series of engine-manouvres, if needed combined with certain flight conditions) and "marker manouvres" in order to be able to identify the running conditions.
As an example of how it helped: Remember that servo slow down that I recommend in order to prevent engine stumble on acceleration?
It IS possible to remedy that stumble by fattening up the idle mixture. But above trendcurve analysis learned that while idle RPM on the ground is as intended, once airborne idle won't come down for the following reason: A rich idle mixture on the ground forces the idle air opening to be larger in order to sustain, say, 1500 RPM. Unloading in the air causes the mixture to lean out however, and the larger air opening and now leaner mixture will easily keep the engine at 4, maybe even 5K and landing becomes a challenge.
Especially in 2-strokes, that run rather rough at lower RPM and rich settings, this is inaudible to the naked ear, but telemetry data combined with overlaid throttle position data makes this very visible. I would not have known this without telemetry and datalogging.
But it can also help identifying non-audible rich or lean spots in the curve by for example flying 30 seconds at 20% throttle, 30 seconds at 30%, 40%, 50 etc and comparing the changes in throttle with th changes in both RPM and CHT.
It is time consuming, but extremely educational if you know what to look for.