uncommanded left roll tendency

Any DA40 related topics

Moderators: Rick, Lance Murray

Post Reply
User avatar
ahmebane
2 Diamonds Member
2 Diamonds Member
FIRST NAME: Holt
Aircraft: DA40
Registration: N275DS
Airport: KMYF

Posts: 11
Joined: Tue Sep 17, 2019 7:05 pm
Has thanked: 11 times

uncommanded left roll tendency

Post by ahmebane »

My fairly-newly-purchased 2003 DA-40 likes to roll left. I've checked the flight characteristics with flaps down a notch & that does not change the roll, so I dont think the flaps are hanging out in the breeze. The roll is coordinated, in that the ball is centered, but hands-off the plane really wants to roll left.

Other observations: the left aileron trim tab is bent upwards slightly, which would counteract this left roll tendency; the rudder trim tab is bent fairly significantly to the right, which would introduce a left rudder force. So these two are fighting each other.

One other observation, and I have no idea is this is normal or whether something happened to the tail sometime in the past. When the elevator is centered on the right winglet (term?) of the horizontal stabilizer, the left side of the elevator is NOT centered/aligned on the left winglet of the horizontal stab. As I write this, I dont 100% recall which way it is off. Seems like the elevator should be centered across the stab. Could this be introducing some roll tendency? I'll go to the airport tomorrow & check which way its off, but I think the elevator is above the stab, which would introduce a downward force on the left side.

Any thoughts? I' a first time owner - how much of the diagnosis & correction should I turn over to the shop? They are a Diamond-certified facility.
User avatar
astaib
4 Diamonds Member
4 Diamonds Member
FIRST NAME: Arnaud
Aircraft: DA40
Registration: FGNJX
Airport: LFPX

Posts: 329
Joined: Mon Feb 26, 2018 9:00 pm
Has thanked: 68 times
Been thanked: 31 times

Re: uncommanded left roll tendency

Post by astaib »

Hi,

Mine also has tendency to go left but I bent the tab in order to compensate it.
Now it’s fine but always a bit different when I’m alone or when we are balanced left/right.

My elevator is straight.

Arnaud.
Arnaud
DA40 Star 180 / 40.026 / 2001
GNS430 NON-WAAS - Steam gauges
Non certified ADS-b
User avatar
Steve
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Steve
Aircraft: DA40
Registration: N432SC
Airport: 1T7

Posts: 1188
Joined: Thu Aug 12, 2010 1:23 am
Has thanked: 26 times
Been thanked: 184 times

Re: uncommanded left roll tendency

Post by Steve »

On my airplane:

The left aileron trim tab is bent upwards slightly,
The rudder trim tab is bent slightly to the left,
The elevator is level with the horizontal stabilizer fairings on both sides.

I haven't touched these in the 19 years since the airplane arrived from the factory, and it flies straight.

Steve
User avatar
Lance Murray
5 Diamonds Member
5 Diamonds Member
FIRST NAME: Lance
Aircraft: DA40

Posts: 1052
Joined: Tue Jul 06, 2010 11:25 pm
Has thanked: 2 times
Been thanked: 74 times

Re: uncommanded left roll tendency

Post by Lance Murray »

Remember that the tab must be removed to be adjusted. If you bend it while attached you risk damage to the surface it is attached to.
Post Reply