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Observing Typhoon H Behavior

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Hey gang
I just took my typhoon h on a test spin. Full battery fully charged controller everything calibrated.
I was basically running the battery down to Storage level. Before
I got a battery warning indication.
I brought it home. The voltage on a controller red 14. 4, I then hit return to home. I noticed a bit of toilet bowling when it was about 15 to 10 feet off the ground. I failed to mention I had it in Turtle mode when I was returning to home.
When it was approximately 20 ft to 25 ft off the ground, I put it in the middle not fast not slow but in the middle. Once I got about 2 ft off the ground it was drifting.
So I got it on the ground, but in a skidding Landing. I was fortunate it did not tip over. Does anyone think
Because the battery was getting low that is why It was drifting ?
All comments welcome.
Thanks
Keith Kuhn
 
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Most likely just some compass drift or GPS. If you notice It drifting just give it a little throttle and go up a little and try again . I use return to home only to bring it back and then manually land the H . Closer to the ground I notice some drifting so always maunaly land the thing
 
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Most likely just some compass drift or GPS. If you notice It drifting just give it a little throttle and go up a little and try again . I use return to home only to bring it back and then manually land the H . Closer to the ground I notice some drifting so always maunaly land the thing

I usually do as you do hit return to home once it starts getting above me 50 ft or so .
I switch it back into angle mode and bring it back manually.
Keith
 

Eagle's Eye Video

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Start bringing the H back at about 14.7V... If you have drifting issues, usually the best solution is to gain some altitude and let it calm down. Those couple of extra tenths of a volt give you time to calmly address any landing issues and still be on the ground by 14.5V without residual drifting contributing to the mix.

Keith let me ask you... do you always make sure when landing, to yaw into the wind, to minimize crosswind gusts?
 
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Start bringing the H back at about 14.7V... If you have drifting issues, usually the best solution is to gain some altitude and let it calm down. Those couple of extra tenths of a volt give you time to calmly address any landing issues and still be on the ground by 14.5V without residual drifting contributing to the mix.

Keith let me ask you... do you always make sure when landing, to yaw into the wind, to minimize crosswind gusts?
There was no wind whatsoever this evening when I flew it.
I very seldom if ever fly in windy conditions. If it is real windy there's no way I will take the typhoon H up Knowing the winds are stronger
At higher altitudes.
 

Eagle's Eye Video

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Ok, well at least that removes wind from the equation.
 
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Drifting near ground is a thing with the typhoon H, or at least it certainly is with mine. In a lot of cases it is caused by aileron not returning to exactly center on the st-16. Check this is in the channel settings rather than the hardware monitor, which allows you to see in more detail if it is hitting exactly 0 when you release the stick. If it's not, calibrate the St-16 using its hidden menu, which should fix it. If it doesn't, you may need to clean the sticks, or you can circumvent it less ideally by setting the rates for aileron so that it stays at 0 output for the first 5% of input off center.

Once you are confident that aileron is centering on 0, then the right thing to do when the H drifts near the ground is to release both sticks and wait for position hold, which should happen quite quickly after you let the sticks go. The thing not to do is to try and counter the drift with additional inputs (unless a collision is imminent of course, but even then it's better to solve it (if you can) with additional throttle rather than directional input), which usually makes things worse, and can be what leads to flips on landing....

Whatever the cause or solution is, it is a thing that happens regularly, so I always make sure I am landing in a nice wide open area where any drift can be allowed to just continue until it sorts itself out. Once you have hover lock, then down throttle is all you need, and it should stay locked all the way to the ground. Just very occasionally it keeps losing that lock, and then it's 'raise to above head height, and hand-catch' time :)
 
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Eagle's Eye Video

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Actually the order of procedure is to clean the sticks first... the calibration process assumes that there are no physical issues with the hardware. Going through the calibration process before cleaning, will make the problem worse.

If oxidation or dirt is causing the limiting of stick movement and return, this can be seen in the hardware monitor. The thread below has instructions on how to clean the sticks:

ST 16 Calibration issue with J2

Also take the time to read all of the Secret Menu thread... it's become one of the most valuable threads on the board.

ST-16 Calibration ( secret menu )
 

FlushVision

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So far as I can remember I have only ever taken my TH down to the first warning at 14.3v twice (there was another instance caused by a sudden voltage drop from 15.0v to 14.3v in the blink of an eye, but that's another story). Both times I saw some strange behavior in the aircraft.

It simply isn't wise to be still in the air at 14.3v. If you are you are at far greater risk of getting problems. As has been said above, you need to be on the ground with motors off in such a way that you never see the first warning...and preferably by 14.5v. That way you are certain to have a bit in reserve should you need to attempt another landing having aborted the first.

The last three flights of my TH last Tuesday I was on the ground after all flights by 14.6v and one of them ws 14.7v. I still managed to get 32 minutes of video over the three flights, though...ample for a 3 minute video edit.
 

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As @Eagle's Eye Video stated I never wait until a battery warning to land. IMHO that’s inviting trouble. It leaves you with a slim margin of error to avoid issues like drifting.

At 14.7V I’m looking to be putting it on the ground. An extra minute or two of flight time isn’t worth it for me.

I’ve experienced drifting at landing as well. I’ve pulled up and tried to see if it will go away without stick input. If it won’t then it’s time to get careful with the sticks, get it controlled as best I can, get it down to less than 4’ AGL and judiciously execute a red button landing with sort presses until it’s inches off the ground and hold down the red button until the props stop. This is why I would never wait until a battery alert.

Afterwards I’ve done a hardware check which has never revealed a problem. So...I’ve sprayed the suspect pot with cleaner and recalibrated in the “secret” menu anyway.

I always check the H after takeoff at 20-30’ AGL to make sure it can hover properly for 30 seconds.

I have a hunch that when the H heats up after a flight and we’re close to the ground for a landing the compass or GPS may not be as accurate as at launch. That’s just a WAG of course.

These kind of drifting landings don’t happen very often for me and very rarely in cool weather.
 
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The H uses a low-quality GPS unit. That's why there are so many reports of odd behavior.
 
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The H uses a low-quality GPS unit. That's why there are so many reports of odd behavior.
The H might have a "low-quality GPS unit" ... I have been in the air for about 35hrs since I bought it late 2016 and it has never showed any drifting / toilet bowling or tricky landings. But...I ALWAYS wait minimum 15minutes if not flewn for 3-4days of moved around 10km east-west or vice versa, for full calibr. Or did Yuneec put a high quality GPS unit in my H? Me too do as "rdonson" do " Always check the H after takeoff at 20-30’ AGL to make sure it can hover properly for 30 seconds.
 
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These kind of drifting landings don’t happen very often for me and very rarely in cool weather.
That's interesting - I hadn't thought heat could be contributing to this before now, but now I come to think of it I got my H right at the start of the current UK heatwave, and it has always been very hot when I am flying, even in the evening when the sun is losing power fast. I also notice that almost as soon as I land I get a GPS warning, though I have never had that whilst actually in the air.
Apparently all this UK heat is coming to an end by Wednesday, so I will be interested to note any differences in behaviour in the cooler weather after that...

I'm also like you in that I start bringing back the H at around 15 volts, and want to be on the ground at 14.7 ideally. I have never so much as even heard the first battery warning, and don't mind limiting my flights to 13-15 minutes to keep those packs happy and unpuffed, and hopefully extend the amount of cycles they will do if never stressed. I admit that might be slightly too cautious, but I do note that I always have time to address any drift problems and still get down to ground for 14.7.
 
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rdonson

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I have nothing to judge by whether the GPS unit in the H is a “low quality” unit or not. I’ve replaced one after a flyaway as I lost faith in it. Still, I wouldn’t know a “high quality” GPS unit if it bit me on the ankle.

@AeroJ I fly with caution as well. Actually I fly like that’s a $700 bill that I’m controlling in the sky. :D ;)

The promising news is that I’ve yet to hear any of these complaints about the H Plus. It’s still new though so I follow it’s exploits closely.
 

PatR

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Heat has always been a factor with electronics. It’s why the military specifies a thermal operational range and requires a lot of empirical test data to establish proof of performance at temperature extremes. Heat is the cause of iPhones left in a hot car failing to function until they cool down. They even display an excessive heat warning message when this happens.

The GPS unit in the H is certainly not the best but where it resides inside the aircraft does more to cause failures than the design of the module. It’s placed in a location that assures it will collect heat from functioning electronics and a discharging battery. It is not well ventilated at this location. In fact, it receives almost zero cooling air. It also sits directly under a black plastic cover that acts virtually the same as a solar thermal collector that lacks a liquid flowing over it to transfer excess heat.

If I was building a drone the last place I would consider locating a GPS unit would be at the hottest area in the aircraft, regardless of the unit’s quality. It also would not be placed directly over the aircraft power supply. I believe Glider would use the same design considerations.

I’m convinced the GPS unit employed in the H would be far more reliable and accurate when installed at a better location. John Hennessey has already proven that with his relocation of the GPS module. I’m not saying the H GPS module is as good as it should be, I’m suggesting it would function a lot better and more reliably if Yuneec had made function a greater priority than airframe appearance and placed the GPS unit in a better environment. The design of the H induces GPS failures. The 920+ uses the same GPS unit but does not experience the positional maladies the H does. What’s different? The GPS module is located forward of the power supply and elevated up and away from the power distribution board, moving the GPS unit away from detrimental heat and EMI influences.
 
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Pat's points above make perfect sense, and it's nice to have a fairly definitive answer as to why this happens, even if it is quite a PITA to rectify / improve it by moving the GPS like John did !
I can live with it if I'm honest - a little drift on landing is hardly a problem if you know how to respond to it, as long that's the limit of the seriousness of problems that occur. I suspect it's not however :)
So I will keep my H for at least a year, and see how it does in all weathers, and if it's looking questionable in other ways I will probably upgrade, or move the GPS next year..
 

rdonson

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As soon as @John Hennessy makes his GPS mod available I will order it and install it. Actually I’d likely order one for each of my H.

My Dremel is at the ready for the mod :)
 
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I’m almost always putting it down at 1st warning. Through testing, my max flight time is about 15m (once) on average around 12m. Sucks!
Not sure why I get such lousy battery life
 

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