I recently had the opportunity to have 2 demo flights in a -22. I want to buy one, but I noticed on both flights there was noticeable wing flutter between 160-190 knots in SMOOTH air!! I also noticed some cabin vibration. I am a very high time ex-jet jock, so I’m positive of what I saw occurring. What’s up here?
…I noticed on both flights there was noticeable wing flutter between 160-190 knots in SMOOTH air…
A more useful description would include your best estimates of the amplitude (say, at the wing tips) and frequency of the oscillations to which you refer. Can you provide same?
I have seen no such oscillations in our SR20.
Taking my SR22 home from Duluth last May I also noticed wingtip up/down vibrations. At that time the left wingtip was the worst, with an amplitude of about 1" and a frequency of about 12Hz. The right wingtip and the horizontal tails also showed up/down vibrations but of smaller amplitudes.
I do not know where the source of the vibration might be. The wingtip motion is likely a symptom, not cause.
At almost 50 hours, the wingtip vibration has diminished with the left wingtip amplitude now about 1/2"
Did you have the auto-pilot engaged??
I had a slow rocking when on autopilot last night. Wingtip displacement was just a few inches but you could see the yoke handle doing a small side to side rocking motion. It was like sitting on a chair with uneven legs and wobbling from side to side.
None of the responses to this guy’s post have been about what he was asking about! He said he noticed wing tip flutter, and since he’s a high time jet pilot, I think we can assume he knows what flutter is (to quote him). Flutter isn’t autopilot induced roll occillations but is aerodynamic in nature, and potentially very dangerous. It’s caused when some part of the aircraft (usually a control surface) becomes resonant with the airflow. If it’s undamped enough and conditions are right, it can rip the airplane apart. That’s why there are weights on ailerons, for example.
At any rate, I think it would be enlightening to discuss the actual problem this guy mentioned. Flutter is not good.
-Jonathan
In reply to:
I have seen no such oscillations in our SR20.
Of course the wings on a 20 are shorter AND you seldom see 160-190 KIAS.
In reply to:
I do not know where the source of the vibration might be. The wingtip motion is likely a symptom, not cause.
This all makes sense now. I think they must have a hidden mechanism that “flaps” the wings! Obviously, this would be actuated by the flap motor, and the posts on the Members forum regarding infant mortatlity of the flap relay have hinted that it is a load-related problem. Takes more to flap stiff new wings I guess.
(Seriously, there were a few reports of wingtip vibration some time ago, and we should query owners to see if this is still prevalent.)
We had a roll trim motor failure shortly there after…you should check yours asap
Paul,
Rocking side-sticks from auto-pilots oscillating are as old/common as this site (and the previous one for that matter)…you can do a search and see what remedies are available…the 1 i remember most had to do with the airlerons being ‘lubed’ and free. Sounds like you recently got your plane so this may not be it…Unfortunately, as i recall, there wasn’t just one simple solution…it will take some trial and error.
Regarding my 20…it often happened…I lube the joints every month…no more rocking chair, ever.
good luck
Interesting because the trim servo just got ‘fixed’. It used to really hunt on the autopilot.
Just because it is new (<100 hours) doesn’t mean it can’t be sticking.
Don,
How do you lube and what do you use?
Thanks,
Paul
N925PW
In reply to:
How do you lube and what do you use?
Click here for a Response! post on the subject.
LPS2 is the preferred lube, although DRYFLOW or LPS 1 is deemed OK. Cirrus warns not to use WD-40.
Ditto Gordon’s post!
I took an SR22 for a test flight (~200 miles round trip) and looked specifically for some form of vibration, as some have mentioned vibrations before, in this forum. I could’nt detect any noticeable/signficant vibration or flutter on my test flight. The wingtips did move up and down a little, at times, but not what I would call an airframe resonance, just the wings flexing with small bumps in the air, because they are composite. So I looked for it, and didn’t see anything noticeable.
I’m planning on checking for this in my acceptance flight for my SR22, as it may be the case that vibration exists in some Cirrus aircraft, but not others.
J.,
SR22 ‘vibrations’ on many planes are still a problem after all this time…, If it doesn’t tear the plane apart…it will certainly act like a ‘cancer’ and eat everything internal up…However, I know Cirrus has made great strides in improving the overall situation.
Fortunately, we haven’t heard of any real bad side effects of this so far…but if it isn’t/wasn’t straightened out…we will.
Frankly, I couldn’t believe they were flying 22’s last year with all that vibration acting as if it were only a slight bug…I supect if the wing tips are ‘fluttering’’, it is time to land the bird…permanently until resolved.
TC