Citabria Rolls to the Left

Thanks, Shawn.
That was very helpful.

I'll let all you folks know when I find out what works.
I'll be talking to my favorite mechanic in the next couple of weeks.

-john

"ShawnD2112" wrote:

Before taking your airplane's wings apart, answer a couple of questions.
You want to solve the roll problem but not add any extra drag to the
airframe, which altering a wing's incidence angle may do.

Are you sure you're straight and level when you're checking for the roll? A
slight, nearly imperceptable climb without correcting rudder will induce
left roll as a secondary effect of the yaw.

Does your airplane have rudder trim? (Most do, I think). If so, it will
only trim for staight and level at one airspeed. Try flying straight and
level at several airspeeds with your feet flat on the floor and see what it
does to the roll. Start off in 5 knt increments and you'll be able to see
the roll become more or less pronounced. If you narrow it down to a cruise
speed that gives no roll, that's the speed your rudder trim is set for. If
you can live with that as your cruise speed, no worries. If you can't,
alter the trim tab to give more or less rudder and try a few more test
flights until you get it right.

If you can't find a no-roll airspeed, or you end up with a huge amount of
rudder trim, then you've probably got a rigging problem as the others here
have suggested. On my Pitts, I had the same problem, but the roll was to
the right. I went through the test procedure just like above and concluded
my wings weren't rigged properly. Because it's experimental, I was able to
re-rig the wings myself with some help from the UK's Pitts expert and she
flies like a dream now. In fact, rerigging the wings took so much drag out
of the airframe that I got an extra 5 knts in the cruise! When I bought her
she only had 34 hours on the airframe and had never been really aerobatted.
In the ensuing 50 hours I put on her, she started to settle and things
stretched and basically settled in, so things needed to be tightened and
readjusted here and there.

If you can rerig the wings yourself, the preference is to take incidence
angle OUT of a wing, rather than put it in. So, if it's rolling left, you
want to raise the trailing edge of the right wing, if you can. Lower angle
of incidence means less induced drag and the wings aren't fighting against
each other, wasting lift.

It's a bit simplistic, but that's the essence of how we solved my rolling
problem. Best of luck with yours!

Shawn
Pitts S-1D G-BKVP
"John Shoemaker" wrote in message
.. .
With my feet flat on the floor, ... not touching the rudder pedals, my
Citabria rolls to the left.

I have to hold right stick a bit for an entire trip.

I was told the the wing had to be "bent".
There are adjustments at the base of each strut on both sides of the
fuselage. I'd like to take in a turn or two and see what happens, but I
don't know which side to adjust.

-shoe

You bet, John. I hope it helps. Rereading my last posting, I'm reminded to
mention that when test flying to find a no-roll airspeed, you're basically
looking to make sure the ball is centered. That's the easiest way to tell
if the rudder trim/airspeed combination is right.

Let us know how you get on.

Shawn
"John" wrote in message
...
Thanks, Shawn.
That was very helpful.

I'll let all you folks know when I find out what works.
I'll be talking to my favorite mechanic in the next couple of weeks.

-john

"ShawnD2112" wrote:

Before taking your airplane's wings apart, answer a couple of questions.
You want to solve the roll problem but not add any extra drag to the
airframe, which altering a wing's incidence angle may do.

Are you sure you're straight and level when you're checking for the roll?
A
slight, nearly imperceptable climb without correcting rudder will induce
left roll as a secondary effect of the yaw.

Does your airplane have rudder trim? (Most do, I think). If so, it
will
only trim for staight and level at one airspeed. Try flying straight and
level at several airspeeds with your feet flat on the floor and see what
it
does to the roll. Start off in 5 knt increments and you'll be able to
see
the roll become more or less pronounced. If you narrow it down to a
cruise
speed that gives no roll, that's the speed your rudder trim is set for.
If
you can live with that as your cruise speed, no worries. If you can't,
alter the trim tab to give more or less rudder and try a few more test
flights until you get it right.

If you can't find a no-roll airspeed, or you end up with a huge amount of
rudder trim, then you've probably got a rigging problem as the others
here
have suggested. On my Pitts, I had the same problem, but the roll was to
the right. I went through the test procedure just like above and
concluded
my wings weren't rigged properly. Because it's experimental, I was able
to
re-rig the wings myself with some help from the UK's Pitts expert and she
flies like a dream now. In fact, rerigging the wings took so much drag
out
of the airframe that I got an extra 5 knts in the cruise! When I bought
her
she only had 34 hours on the airframe and had never been really
aerobatted.
In the ensuing 50 hours I put on her, she started to settle and things
stretched and basically settled in, so things needed to be tightened and
readjusted here and there.

If you can rerig the wings yourself, the preference is to take incidence
angle OUT of a wing, rather than put it in. So, if it's rolling left,
you
want to raise the trailing edge of the right wing, if you can. Lower
angle
of incidence means less induced drag and the wings aren't fighting
against
each other, wasting lift.

It's a bit simplistic, but that's the essence of how we solved my rolling
problem. Best of luck with yours!

Shawn
Pitts S-1D G-BKVP
"John Shoemaker" wrote in message
.. .
With my feet flat on the floor, ... not touching the rudder pedals, my
Citabria rolls to the left.

I have to hold right stick a bit for an entire trip.

I was told the the wing had to be "bent".
There are adjustments at the base of each strut on both sides of the
fuselage. I'd like to take in a turn or two and see what happens, but I
don't know which side to adjust.

-shoe