NTSB Safety Alert CH 601

Wanna see an airplane break up from flutter?

Watch the movie clip:

http://www.velozia.com/?p=1387

BTW, the Auguste Raspet Memorial Department of Aeronautical
Engineering at Mississippi State University does flutter testing on
airplanes, including experimentals. Bring your checkbook.

White Lightning designer and Citadel-educated engineer Nick Jones had
the White Lightning successfully tested there.

I have balanced a set of flight controls with lead embedded in the
leading edges--- rudder, elevator, ailerons --- for the White
Lightning; and no, they are not completely balanced, just enough to
avoid flutter up to about 350 kts. This is a 220 kt. cruise aircraft.

jl wrote:
Wanna see an airplane break up from flutter?

Watch the movie clip:

http://www.velozia.com/?p=1387

BTW, the Auguste Raspet Memorial Department of Aeronautical
Engineering at Mississippi State University does flutter testing on
airplanes, including experimentals. Bring your checkbook.

White Lightning designer and Citadel-educated engineer Nick Jones had
the White Lightning successfully tested there.

I have balanced a set of flight controls with lead embedded in the
leading edges--- rudder, elevator, ailerons --- for the White
Lightning; and no, they are not completely balanced, just enough to
avoid flutter up to about 350 kts. This is a 220 kt. cruise aircraft.


Great post! That flying wing breakup looked kinda like a divergent
pitch oscillation to me. There is nothing like a first hand account
of a surface balancing - any idea what proportion of the control
surface weight was balanced? That would be an interesting value!

Regards

Brian W

jl wrote:
Wanna see an airplane break up from flutter?

Watch the movie clip:

http://www.velozia.com/?p=1387

Here's the proper way to handle flutter:

http://www.youtube.com/watch?v=a-qS7oN-3tA

Sorry - it's an experimental aircraft in the traditional sense, so probably
not topical for a "homebuilt" group. ;-)

Morgans wrote:
"Bob Hoover" wrote

For anyone unfamiliar with bureaucratic formats, skipping to the last
page of the 12 page report, will give you a complete list of the
highlights. But the real message is more subtle than it appears. The
real message offers a polite Heads-Up to ALL American airmen, telling
us that if we can't keep our house in order there are plenty of
bureaucrats more than eager to jump in and take care of that little
matter for us. (Need I mention that bureaucrats don't come cheap?)

I STRONGLY suggest you read the whole report and be prepared to act on
it accordingly, when appropriate.

-R.S.Hoover

***********************************************8
Zactly. Even better, I can't imagine flying a plane that might come apart
in mid air (for no apparent reason) without fixing the problem causing it to
come apart. Perhaps people should consider that fact, too.

Does anyone know why there is no mass ballancing (as is common practice) on
the ailerons, in the first place?

The Zenair Zodiac uses wing warping. (They call it a "hingeless
aileron"). Looks pretty springy to me.
http://www.zenithair.com/kit-data/ht-aileron.html

John Kimmel

John Kimmel wrote:

The Zenair Zodiac uses wing warping. (They call it a "hingeless
aileron").

Not all of them. Zenair has offered a piano-hinged aileron for quite a
while...the SLSA version of the CH601 uses 'em, and some kit builders
have opted for them. Two of the wing-failure accidents involved SLSA
Zenairs, which have the piano hinges. Haven't heard the type of
ailerons for the others.

Ron Wanttaja

Ron Wanttaja wrote:
John Kimmel wrote:

The Zenair Zodiac uses wing warping. (They call it a "hingeless
aileron").

Not all of them. Zenair has offered a piano-hinged aileron for quite a
while...the SLSA version of the CH601 uses 'em, and some kit builders
have opted for them. Two of the wing-failure accidents involved SLSA
Zenairs, which have the piano hinges. Haven't heard the type of
ailerons for the others.

Ron Wanttaja



As best we can find out NONE of the accident aircraft had the hingeless
ailerons. This could explain why there has been no problems until the
last few years when the hinges started replacing the hingeless.

In fact the only commonality that I can find between the accident
aircraft is hinged ailerons and the sort of strange (for an plane that
the majority of the fleet is EXP-HB) fact that none of the aircraft were
flown by the builder.