Bravo Roll to the Left

[jcollier]

Hey guys!  I hope all are doing well.  I have an issue we can't seem to find the "smoking gun" yet.

Within the last few months, I have noticed a "roll" to the left when flying my Bravo.  The roll is more significant the faster I go.  I have attached a short video.  In the video, I take my hand off the yoke when level, you see the roll to the left.  I straighten to wings level and take my hand off the yoke again around 20 sec.

A few points.  There has been no hangar rash, no moderate or hard turbulence, looking down the trailing edges they are all straight.  The gear has been swung and the shop stated the doors were firmly closed (meaning there wasn't anything able to come open and produce drag).  The shop also checked all the rigging to the MMM standards.  They even measured nose to wingtip and wingtip to tail for symmetry.  All was good.

During a maintenance flight, once the plane was trimmed for straight & level flight (and rolling to the left), if you input right rudder and swing the ball about "1/2 ball out to the left", the rolling stops and the plane flies without any rolling, whatsoever.  This prompted us to level the plane per MMM Ch 8-00-00, then level the inclinometer to the Aircraft.  The ball was literally 1/2 ball out to the left.  We thought we had found the "smoking gun", if you will.  However, after leveling everything, we went for a maintenance flight.  Once at straight and level flight and trimmed, I take my hand off the yoke and it immediately begins the roll to the left.  I put in right rudder and swing the ball to "1/2 ball out to the left" and the roll goes away.  

The autopilot is also being affected by the roll.  The AP is strong enough to maintain straight and level flight.  It has a very brisk turn to the left....(obviously).  It struggles to straighten from a turn to the left.  If I am in a descent to the left and gaining speed, it can't overcome the roll and straighten.  Also, at S&L flight, the AP is very sluggish to the right, since it has to 1st overcome the left roll.  I don't think this is an AP issue and it does it when the AP is not engaged.  If the rudder trim is used to swing the ball "1/2 ball out to the left", the AP is very responsive Right and Left.  

 

Any insight would be GREATLY appreciated and I thank you, in advance.  This is extremely frustrating.  I can't point any one specific thing that started this rolling.

 

Kindest regards,

Joshua

IMG_4218.MOV

[carusoam]

Joshua, see if you can post the video using YouTube...  a lot of iPad users will be able to follow along this way...

my long body flies straight using small amounts of rudder trim to center the ball. Right for T/O and climb.  Centered in flight. And a touch of left for descent...

Flying with a heavy left wing...

• Marauder's girls are sitting on the left side.
• fuel only in the left tank, none in the right.
• Something is interrupting the rudder centering set-up.

How well does the plane track the centerline while taxiing? Can you steer using the rudder trim?

PP thoughts only, not a Bravo pilot or mechanic.

Best regards,

-a-

[mike_elliott]

Hi Joshua, how have you been? Were the trailing edges of the airlerons bent a bit by chance? I have seen shops "tweak" them to prevent a drooping wing. It doesnt take much, just finger pressure to change the flight characteristic at Bravo cruise speeds.

 

[N201MKTurbo]

Perhaps one of your rudder aileron interconnect springs broke.

[rpcc]

Engine mounts?

[FoxMike]

I had a somewhat similar problem years ago.  I found the factory had misrigged the flaps. Left side was 0d and right side was up 5d.  I would suggest you measure the flaps.  You may find the stops on one side or the other to to be out of adjustment.

[Airways]

On 8/30/2017 at 12:31 AM, jcollier said:

Hey guys!  I hope all are doing well.  I have an issue we can't seem to find the "smoking gun" yet.

Within the last few months, I have noticed a "roll" to the left when flying my Bravo.  The roll is more significant the faster I go.  I have attached a short video.  In the video, I take my hand off the yoke when level, you see the roll to the left.  I straighten to wings level and take my hand off the yoke again around 20 sec.

A few points.  There has been no hangar rash, no moderate or hard turbulence, looking down the trailing edges they are all straight.  The gear has been swung and the shop stated the doors were firmly closed (meaning there wasn't anything able to come open and produce drag).  The shop also checked all the rigging to the MMM standards.  They even measured nose to wingtip and wingtip to tail for symmetry.  All was good.

During a maintenance flight, once the plane was trimmed for straight & level flight (and rolling to the left), if you input right rudder and swing the ball about "1/2 ball out to the left", the rolling stops and the plane flies without any rolling, whatsoever.  This prompted us to level the plane per MMM Ch 8-00-00, then level the inclinometer to the Aircraft.  The ball was literally 1/2 ball out to the left.  We thought we had found the "smoking gun", if you will.  However, after leveling everything, we went for a maintenance flight.  Once at straight and level flight and trimmed, I take my hand off the yoke and it immediately begins the roll to the left.  I put in right rudder and swing the ball to "1/2 ball out to the left" and the roll goes away.  

The autopilot is also being affected by the roll.  The AP is strong enough to maintain straight and level flight.  It has a very brisk turn to the left....(obviously).  It struggles to straighten from a turn to the left.  If I am in a descent to the left and gaining speed, it can't overcome the roll and straighten.  Also, at S&L flight, the AP is very sluggish to the right, since it has to 1st overcome the left roll.  I don't think this is an AP issue and it does it when the AP is not engaged.  If the rudder trim is used to swing the ball "1/2 ball out to the left", the AP is very responsive Right and Left.  

 

Any insight would be GREATLY appreciated and I thank you, in advance.  This is extremely frustrating.  I can't point any one specific thing that started this rolling.

 

Kindest regards,

Joshua

IMG_4218.MOV

Did you find a cause for this problem ?  My M20K shows the same behaviour and it looks like it's not aileron-related...

[Davidv]

Did your Bravo recently spend time in CA or NY?

In all seriousness I'd check the flaps as previously mentioned.  I assume your shop used the Mooney travel boards to make sure the flaps, ailerons, and rudder were all where they are supposed to be.  Do you have any pictures of your ailerons in flight so we can see how they meet the edge of the flaps?

[irishpilot]

Flaps and rudder as previously mentioned. 

[carusoam]

15 hours ago, Airways said:

Did you find a cause for this problem ?  My M20K shows the same behaviour and it looks like it's not aileron-related...

JC hasn’t been around for a while...  

He may get an email since you quoted his post... (depending on how he has his MS set up...)

Best regards,

-a-

[Rick Junkin]

On 4/12/2021 at 8:28 AM, Airways said:

Did you find a cause for this problem ?  My M20K shows the same behaviour and it looks like it's not aileron-related...

Have you checked your elevators for symmetry? @Airways

My elevators were out of symmetry by about a degree and a half (about 3/8" at the bob weights) and was enough in cruise to cause the autopilot to hold left aileron, which required left rudder trim for coordinated flight. Lynn at AGL Aviation @AGL Aviation adjusted it for me yesterday and I'm back to zero trim and centered yokes in cruise.

Cheers,
Rick

[Airways]

And how was your handflying? Did your acft initiate a roll the moment you let go of the yoke ? My yokes are centered but a left roll happens anyway.  But I’ll add the elevators to the list and hopefully we’ll figure it out during the next annual.

[Rick Junkin]

8 hours ago, Airways said:

And how was your handflying? Did your acft initiate a roll the moment you let go of the yoke ? My yokes are centered but a left roll happens anyway.  But I’ll add the elevators to the list and hopefully we’ll figure it out during the next annual.

@Airways Unfortunately turbulence over the "mountains" between KMRN and KGKT didn't allow a good assessment of hands-free performance. I'll follow up with that on the next smooth air day here.

It's easy to eyeball if your elevators are out - stand at the rudder and pull up on both elevators until one of the bob weights is streamlined with the horizontal stab. Hold it there and look to see if the other bob weight is in the same relative position. If the left bob weight is inline and the right one looks higher protruding above the horizontal stab it will induce a left roll.

EDIT: I think you were asking about hand flying before the adjustment - yes, I had to hold slight left aileron to keep the wings level. The airplane would roll to the right hands off. In my case the the right elevator bob weight was below the horizontal stab surface with the left bob weight inline, which induced a right roll.

Cheers,
Rick

Edited April 22, 2021 by Junkman

[Airways]

Thanks a lot for the input, Rick.  I’m heading to the airport today and I’ll have a good look at that elevator !

[Airways]

You might be onto something, @Junkman.  I definitely saw asymmetry in the elevator.  Sent some remarks to the a&p. 

 

 

[Rick Junkin]

19 minutes ago, Airways said:

You might be onto something, @Junkman.  I definitely saw asymmetry in the elevator.  Sent some remarks to the a&p. 

 

 

It's important to have a protractor to determine which elevator is "right", if either are, and then align them properly. Hopefully your A&P is Mooney-savvy and is familiar with the process. Good luck!

Cheers,
Rick