[rebel-builders] Moose Structural Failure ! Possible rudder

[Wayne G. O'Shea]

You already know my thoughts on it Ted and I'll keep them private for now.
Thinking cap is still in motion though..

Wayne

----- Original Message -----
From: "Ted Waltman" <ted@vafm.org>
To: <rebel-builders@dcsol.com>
Sent: Tuesday, October 04, 2011 5:49 PM
Subject: [rebel-builders] Moose Structural Failure ! Possible rudder flutter
(long post)


[quote]I posted two pictures (Area 107 S/M-Fuselage) of my buckled fuselage due to
what I suspect-but have not yet confirmed-is rudder flutter. Below is a
synopsis of the event-from which I and my passengers are blessed to have
survived. I will post more information on this event as I further analyze
the structure while I make repairs--and after I receive input from NTSB
investigators who are looking at the plane in person.

Note: No rudder counter-weight / balancing is required by the build
manual.
The standard rudder is therefore aft (aft of rudder hinge point that is)
heavy. I added electric rudder trim (servo motor & related hardware) as
well as a curved rudder top--both of which add yet more weight aft of the
rudder hinge point.

I believe this video illustrates what happens with a rudder whose weight
is
aft of the hinge point is very telling (47 seconds long-well worth
watching!!): http://tinyurl.com/44p6o35 (when he waves his hand in front
of
the rudder he is simulating a wind gust).

Rest assured, when I make repairs, I will dynamically balance both my
rudder
and my elevator (which already has some counter-weight but perhaps not
enough?).

Ted Waltman

Moose N384JP Denver, Colorado

-----------

Event synopsis

----------

Departed 18V at approximately 7:40 a.m. after filling fuel tanks
completely
full (80.0 total gallons) and checking oil full at 16 quarts. Climbed to
5,500' cruise altitude on heading of approximately 97 degrees magnetic on
a
direct course to KHYS.

After approximately