My wings began flapping - scary - what was it?

[SkyPirate]

2 completely different construction formats,..the zenith also used the skin for the aileron hinge,..their fix was to make the top and bottom of the spar stronger,..and beefed up the carry thru's

[SkyPirate]

Im curious if the wing was twisting or just rapidly flexing up and down

[SkyPirate]

an example of how much a wing with round spars can flex,..the zenith could never with stand this

[Av8r3400]

In 30 years of history, with thousands of aircraft flying, there has never been an in flight breakup of an Avid or Kitfox.

There are some pretty shoddy built airplanes out there. (Honest truth) Not one has failed. That says a lot about the design. Even built poorly they are still a safe aircraft.



This is one of the many reasons I chose to join the family.

[SkyPirate]

amen......

[rogerh12]

I too think that if there was a flaw in the kitfox design that allowed a flutter to occur, it would have been found out years ago. So, if it did flutter, something must be "wrong" or loose, or worn out. But one thing I do find interesting, sadly, is that when the first Zenith XL guy reported that he was "scared to death" seeing his wings flutter, the response from most of the others on the forum was: No it didn't, you don't know what flutter is, your a bad pilot, your an idiot,,,, it just got worse from there. Then another guy reported the same problem, and got the same response, and again, and then the wings started breaking off.....

We, as a group, need to take any report of a possible flutter seriously, and not point a finger back at the pilot, or poohoo his reports. I don't want to see this happen again. Not on the Kitfox too.
Roger

[Micro Mong Bldr]

Hi Folks,
I haven't owned the 'Fox very long, previous owner said he'd never seen any flutter, I've only flown it so far on "perfect" days - as flexy as the outer wing panels are, maybe it was my first encounter with its normal response to bumps?
Cheers,
Larry

[Dave F]

So here's the scenario, looking for feedback on what
I experienced:

Model 3, 90hours total time, I have 50 of those since I purchased it.
9am in Oregon
winds @ 800ft AGL: 10-15mph from the north.
Direction flying: South
Airspeed Indicated: 75mph
Thermals: Moderate to Heavy, it's a 100degree day now.
Engine: 582
RPM: 5000ish
Load: 950lbs gross

While minding my own business the wings suddenly
began oscillating up and down, both sides it appeared. Lasted
3-4 seconds. I was about a mile south of some rolling hills.

I pulled the power to 4000, pulled the nose back a touch to drop
it below 70mph... and waited. It stopped. Full inpsection shows
NOTHING loose etc... remainder of flight was normal (but quite
gusty, bumpy, and not much fun due to weather).

So please avoid wild speculations (I can do that on my own haha!)
if you've had this happen or KNOW what this was from experience
preferably in a model3 please let me know... just wanting to double
check this isn't a known issue of any kind and was truely just the
airflow/thermals that prevailed.

Thanks in advance!
~Wild

>>... just wanting to double
check this isn't a known issue of any kind and was truely just the
airflow/thermals that prevailed.<<


I am going to agree that is sounds like wing flexing .

Cheers

[ofergd]

Hi
I have a KF-II and I had the same experience. It only happens in rough air. It is caused by free play in the aileron control system. In my case it was caused by exra play in the plasic bearing between the turtledeck and the body at the wing root. Eliminating the free play in the control system stoped the vibrations I experienced.

[Peteohms]

I have a Kitfox 3 and have about 660 hours flying it. I have never experienced any wing flutter. I cruise about 90 mph.