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Bouncing up after landing

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Hi All,

Ok I have a wee problem as of the past two flights.

My H has been perfect since its maiden flight last Oct 2016. It is the pro RS version.

Lat two flights when I have landed (perfectly as usual) I have let go of the throttle to move my left index finger to the red button to kill the motors and as soon as I let go of the stick it starts to take off again!! Only an inch or so but I then have to press the red button and 'drop it' onto the floor.

I always fly in angle mode, I am aware of the OA issues regarding landing (I rarely use OA as most work is done at high altitude, 70m+) and not approaching the H till the powers off etc.
I rebind, calibrate compass, accelerometer and gimbal prior to EVERY flight and give the H a good 15 min on the ground to settle in prior to first flight.

I am wondering about the following potential issues;

1. The H always sets its 'home' altitude to zero at boot up, If I am landing it a little lower than the take off position could this be an issue.

2. I have been told that barometric pressure is used to monitor altitude, I doubt this. I believe the large number of satellites required by the H to get 'GPS good' status is because it uses GPS for altitude as well as positioning when outdoors. Again this may be causing an error if I am landing lower than take off location.

3. Last flight was into a large china clay pit, during this time I was flying around 30m lower than take off location, no problem. This contradicts previous ideas so I am confused.

Any ideas chaps and chapettes??
 
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I had the same issue couple of weeks ago. Re calibrated and all was good

Bill W.
 
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Never let go of the throttle until after the props have stopped. If the throttle returns to center, the TH will try to hold its altitude, so the props will speed up until the GPS and barometer tell the TH that it is climbing. Also, if you land on an uneven surface, it will try to level itself.
 
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Never let go of the throttle until after the props have stopped. If the throttle returns to center, the TH will try to hold its altitude, so the props will speed up until the GPS and barometer tell the TH that it is climbing. Also, if you land on an uneven surface, it will try to level itself.
I did that. They never would go to idle.

Bill W.
 
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Hi All,

Ok I have a wee problem as of the past two flights.

My H has been perfect since its maiden flight last Oct 2016. It is the pro RS version.

Lat two flights when I have landed (perfectly as usual) I have let go of the throttle to move my left index finger to the red button to kill the motors and as soon as I let go of the stick it starts to take off again!! Only an inch or so but I then have to press the red button and 'drop it' onto the floor.

I always fly in angle mode, I am aware of the OA issues regarding landing (I rarely use OA as most work is done at high altitude, 70m+) and not approaching the H till the powers off etc.
I rebind, calibrate compass, accelerometer and gimbal prior to EVERY flight and give the H a good 15 min on the ground to settle in prior to first flight.

I am wondering about the following potential issues;

1. The H always sets its 'home' altitude to zero at boot up, If I am landing it a little lower than the take off position could this be an issue.

2. I have been told that barometric pressure is used to monitor altitude, I doubt this. I believe the large number of satellites required by the H to get 'GPS good' status is because it uses GPS for altitude as well as positioning when outdoors. Again this may be causing an error if I am landing lower than take off location.

3. Last flight was into a large china clay pit, during this time I was flying around 30m lower than take off location, no problem. This contradicts previous ideas so I am confused.

Any ideas chaps and chapettes??
Have you noticed any difference on your bouncing effect based upon the type of surface you are landing on? For example, I have noticed that when I land on my landing pad on a roadway or asphalt and concrete I get a little bit of a bounce upon those surfaces. But if my pad is in a field or on a grassy type surface, my typhoon seem to land more firmly and without bounce. Just a thought.

I am no expert, but what you may be experiencing is some propeller backwash from hovering just a bit too long above your landing site and landing your H into the invisible air wash there. When I have done that, I noticed my Typhoon was a little more reluctant to sit on the ground for me and allow me to hit the red button for three seconds and power it down. I think it may still give it the feeling that it is about to take flight.


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Never let go of the throttle until after the props have stopped. If the throttle returns to center, the TH will try to hold its altitude, so the props will speed up until the GPS and barometer tell the TH that it is climbing. Also, if you land on an uneven surface, it will try to level itself.
My experience is that when you hold the throttle stick all the way to the bottom for a few seconds after landing, the motors will drop to idle speed. If you let go of the throttle then, the H will not try to self level. (Then you can press the red button to shut off the motors.) The motors should not speed up again unless you move the throttle ABOVE 50%. If release the stick quickly, it can bounce above 50% and try to take off or self level. If you release the stick gently to center, it will not do this. If it behaves differently, then you may need to recalibrate your ST16.
 
R

Rayray

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My experience is that when you hold the throttle stick all the way to the bottom for a few seconds after landing, the motors will drop to idle speed. If you let go of the throttle then, the H will not try to self level. (Then you can press the red button to shut off the motors.) The motors should not speed up again unless you move the throttle ABOVE 50%. If release the stick quickly, it can bounce above 50% and try to take off or self level. If you release the stick gently to center, it will not do this. If it behaves differently, then you may need to recalibrate your ST16.
I believe this is completely correct. Also, GPS not used for height, only the barometric sensor, but nothing to do with landing...
 

PatR

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Perhaps "recalibrating" muscle memory is in order. If we maintain aft stick pressure on the throttle stick for a few moments after landing, long enough for the aircraft to recognize it has landed, the "bounce" problems are no longer there.

Another assist is not making a singular descent to landing. Stop the descent a couple feet from the ground and allow the H to stabilize in a hover for a moment before setting it on the ground. That also permits you the opportunity to better gauge the wind and input the correct response to counter it when touching down.


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Also, Were you at RABBIT or TURTLE setting??? That can make a big difference in the "bouncing". I always do the final 10 - 20 Ft at TURTLE setting.
 
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Perhaps "recalibrating" muscle memory is in order. If we maintain aft stick pressure on the throttle stick for a few moments after landing, long enough for the aircraft to recognize it has landed, the "bounce" problems are no longer there.

Another assist is not making a singular descent to landing. Stop the descent a couple feet from the ground and allow the H to stabilize in a hover for a moment before setting it on the ground. That also permits you the opportunity to better gauge the wind and input the correct response to counter it when touching down.


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Hey Pat, I will endeavour to recalibrate my 'muscle memory' just gotta find them first :)

I think the top tip here is a momentary hover prior to touch down, I choose rabbit/turtle dependent on conditions, if its nice, calm predictable weather turtle is fine. If its gusting etc I like to get it down fast as soon as I make the 'command decision' to land
 
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This is a small snippet from my COM / Checklist, I had a problem similar to this a while ago when the motors/engine will not transition into idle. You can also hear a pitch change when it does transition into idle.

If I fail to successfully land I try to take off again come back around and land again. (Battery Permitting) The thing is to ensure the throttle is retarded all the way from touch down until you either shutdown the motors or until the master power is turned off. (Master power is the UAV main ON/OFF switch)

Edit: If the problem persists send it to Yuneec.

Hope this helps.

Cheers

Landing Checklist:
- Gear = Down/Extended
- Sensitivity = Low/Rabbit
- Trim Tabs = As Rqrd.
- Obs. Avoid = Off
- Flight Mode Selector = Angle
- Landing Pad = As Rqrd.
- Landing Site = Clear
- TO/GA Path = Checked
(Begin landing)
- Throttle = ****** (maintain until shutdown)
- Check for RPM Pitch change / motors transition to Idle​
- Engine/Motor* = Cut Off / Off

*While maintaining retarding the throttle.

Landing Failure Checklist:
--If engine/motor refuses to transition into idle / RPM Pitch change hand catching may be req if landing attempt 2 fail.--

- Aircraft/UAV Position = Rear / Battery Compartment Facing Operator
- Gear = Down/Extended
- Sensitivity = Low/Rabbit
- Trim Tabs = As Rqrd.
- Obs. Avoid = Off
- Flight Mode Selector = Angle
- TO/GA Path = Checked
- Landing Site = Clear (no un-auth. persons within 10-20ft)
- (Begin landing)
- Throttle = ****** (maintain until shutdown)
- Check for RPM Pitch change / motors transition to Idle​
- Engine/Motor* = Cut Off / Off

-- If engine/motor refuses to Cut Off / Off carefully and firmly remove the battery.--
 

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