US L-13 AD

Last weekend I got a bit more information about the "Llewellen
Modification" mentioned below. It is said to be a steel reinforcing
strap applied to the outside of the wing along the wing main spar for
2/3 semispan or so. If that is true, it's great from a structural
perspective. From the aerodynamic perspective, maybe not so much...

Thanks, Bob K.



On Jul 15, 7:31*am, Bob Kuykendall wrote:
On Jul 15, 3:53*am, Graemec wrote:

A whole lot of the field data is in. *The highest hour Blaniks have
always been in Australia
and a large amount of work has already been done. *The AD below was
issued in 1989:

http://2009.gfa.org.au/Docs/ADs/gfa%...0issue%201.pdf

Thanks for posting that! It answers a question that I and some others
have been asking: "What the heck is the difference between an L-13A1
and a regular old L-13?

From the Australian GFA AD 369 document linked above:

+ In 1984 D.J Llewellen and Riley Aeronautics developed and
+ received C.A.A. certification for a modification of the Blanik
+ wing to extend its fatigue life to nominaly three times the
+ basic Blanik L-13 life.
+
+ Up to the date of this Airworthiness Directive 9 Blaniks have
+ been modified being re-certified as "BLANIK L-13A1 gliders.
+ Riley Aeronautics (Australia) Pty.Ltd. hold Supplemental
+ Type Certificate No 96-1 covering this modification program.

Thanks again, Bob K.