Motors spooling up on their own

[Channel70Productions]

All updates on everything has been installed. Despite recalibration of sticks and IMU, the motors, after the first flight and landing and hands off of everything, will slowly increase rpm to the point the bird will want to flop onto one side. Prior to the first flight of the day, I can start the motors and they will idle at a steady speed - probably until the battery is depleted. After a flight and landing, and releasing the sticks, 20-30 seconds will pass and then the rpm's begin to increase. Pulling down on the left stick almost to engine cut off position has no effect. All the way down does shut off the motors. If I shut everything down and restart the RC, wifi amp, and Phantom from scratch, the problem again occurs after the initial flight. Anyone else experience this?

 

[N017RW]

All updates on everything has been installed. Despite recalibration of sticks and IMU, the motors, after the first flight and landing and hands off of everything, will slowly increase rpm to the point the bird will want to flop onto one side. Prior to the first flight of the day, I can start the motors and they will idle at a steady speed - probably until the battery is depleted. After a flight and landing, and releasing the sticks, 20-30 seconds will pass and then the rpm's begin to increase. Pulling down on the left stick almost to engine cut off position has no effect. All the down does shut off the motors. If I shut everything down and restart the RC, wifi amp, and Phantom from scratch, the problem again occurs after the initial flight. Anyone else experience this?

Yes! Was going to let it idle for deeper battery discharge (I have a P2 with 3.06).

It never was allowed to tip over but it looked like it would have.

 

[DBS]

Mine does that after a landing also... I saw my buddy mede8er have the same thing happen to him... it seems after a flight the motors don't want to go back to "idle" when left stick is centered... they want to go back to "hover"

I thought this was normal... so I shut down the motors and then csc again if I want to idle and drain battery or whatever :ugeek:

 

[Phantom_Menace66]

All updates on everything has been installed. Despite recalibration of sticks and IMU, the motors, after the first flight and landing and hands off of everything, will slowly increase rpm to the point the bird will want to flop onto one side. Prior to the first flight of the day, I can start the motors and they will idle at a steady speed - probably until the battery is depleted. After a flight and landing, and releasing the sticks, 20-30 seconds will pass and then the rpm's begin to increase. Pulling down on the left stick almost to engine cut off position has no effect. All the way down does shut off the motors. If I shut everything down and restart the RC, wifi amp, and Phantom from scratch, the problem again occurs after the initial flight. Anyone else experience this?

I've had the same issue with both my P2V+'s (First one crashed months ago). It seems to want to take off again but doesn't throttle up enough to get off the ground, just enough to fall over.... Some bug in the system somewhere....

 

[Mako79]

I carry mine in a back pack. I noticed if I leave it sitting up, the IMU gets 3.0 or more mod. I end up trying to calibrate it on a flat surface or in the field. The IMU essentially feeds info to Naza to keep her stable. If she thinks she's on an angle, the Naza will counter and spin up the props to balance.

 

[N017RW]

I carry mine in a back pack. I noticed if I leave it sitting up, the IMU gets 3.0 or more mod. I end up trying to calibrate it on a flat surface or in the field. The IMU essentially feeds info to Naza to keep her stable. If she thinks she's on an angle, the Naza will counter and spin up the props to balance.

Not sure that's what were talking about here...

Fly your a/c, land it, release throttle (to mid position), a/c motors will 'idle, then 'it' slowly increases motor rpms resulting in a tip over if not caught.

 

[DCGOO]

I would consider that to be normal. Centered sticks is normally hovering. If you want it to stay down, you have to pull down on the left stick. If the sticks are left centered, the bird thinks it is hovering, not on the ground. GPS/barometer altitude is not that stable. If the bird thinks it is descending, it will add power to maintain altitude, even it is "hovering" on the ground. If you want it to sit, turn it off.

 

[N017RW]

Not saying it's not normal but maybe inherent is better.

It likely wasn't anticipated by the programmers that someone would do this (but apparently a few have) .

 

[BlackTracer]

I would consider that to be normal. Centered sticks is normally hovering. If you want it to stay down, you have to pull down on the left stick. If the sticks are left centered, the bird thinks it is hovering, not on the ground. GPS/barometer altitude is not that stable. If the bird thinks it is descending, it will add power to maintain altitude, even it is "hovering" on the ground. If you want it to sit, turn it off.

+1

My experience has been that when it touches down, the motors spin down to idle speed. So the bird clearly knows it is not hovering and has landed. Otherwise left stick down wouldn't turn off the motors. So why would it think it is hovering after that? Maybe there is a timer that starts when the motors go to idle on the ground, that expires if you don't turn the motors off via left stick down or CSC.

I think I can test this with a hand catch because it seems to control the motors (goes to idle) the same way when I grab it. I will try it tonight.

 

[Dirty Bird]

Odd, I haven't noticed this. Usually when I land I shut the motors down immediately, but I have restarted them and let them run at idle to bring the batteries down to 8%. Never had mine spool up again.

 

[BlackTracer]

Odd, I haven't noticed this. Usually when I land I shut the motors down immediately, but I have restarted them and let them run at idle to bring the batteries down to 8%. Never had mine spool up again.

Well this may reinforce my timer theory. The timer doesn't start on a stationary power up. Only on a "landing" when motors are already spinning.

 

[DCGOO]

Except, if you not do a left stick shutdown, instead returning the stick to center, the bird assumes you are flying (hovering) again.

Basically think of the left stick having three modes: Centered = hovering; Down: = descending, (limited by the ground); and Up = Ascending = Climbing. I do not think there is any difference whether the aircraft is on the ground or in the air. As we all know the aircraft moves around slightly when hovering in the air due to variances in altitude measurement. Why would this not still be the case when it is sitting on the ground?

I certainly had nothing to do with developing the software algorithms involved, but it sure seems to me like that would be logical behavior.

The one exception to that might be upon initial power up, I've never had the bird ascend until I at least pushed up once. So apparently there is an exception for just after first spin up (again I am just guessing).

 

[Double-D]

Very interesting. Something I'll have to try.

 

[sar104]

I would consider that to be normal. Centered sticks is normally hovering. If you want it to stay down, you have to pull down on the left stick. If the sticks are left centered, the bird thinks it is hovering, not on the ground. GPS/barometer altitude is not that stable. If the bird thinks it is descending, it will add power to maintain altitude, even it is "hovering" on the ground. If you want it to sit, turn it off.

+1

My experience has been that when it touches down, the motors spin down to idle speed. So the bird clearly knows it is not hovering and has landed. Otherwise left stick down wouldn't turn off the motors. So why would it think it is hovering after that? Maybe there is a timer that starts when the motors go to idle on the ground, that expires if you don't turn the motors off via left stick down or CSC.

I think I can test this with a hand catch because it seems to control the motors (goes to idle) the same way when I grab it. I will try it tonight.

That is not correct. On the ground before takeoff (sticks centered = idle) is not the same as on the ground after landing (sticks centered = maintain altitude). The motors do not go to idle after a manual landing - in fact the FC doesn't know that it landed at all. Left stick fully down turns off the motors after 3 seconds if it detects no further descent. Centered sticks still commands a hover, and it will spool up the motors if it detects reducing altitude (increasing barometric pressure). Increased power to the motors on the ground will actually tend to cause an increase in pressure reading due to air flow stagnation (ground effect), leading to a positive feedback loop.

 

[BlackTracer]

When I land, my motors reduce speed to the same speed as when I start them before takeoff. This is what i mean by idle speed. I always immediately go left stick down after landing so I have never experienced a spool up like the OP.

 

[Fulcanic]

I have had the same experience with my PV+. For me recalibration of the RC solved the problem perfectly!