Charlie and Tupper England wrote:

Is this relevant to the ACRE prop design process?

Charlie England

>From AvWeb today:

HAMILTON PROP AIRWORTHINESS DIRECTIVE: It seems

that some

Hamilton
Sundstrand model 247F propellers, which are

frequently found

on
Aerospatiale ATR-72 and Xian MA-60 airplanes, are

having a

bit of
trouble staying together.  The FAA counts nine

reports of

blades
partially slipping at the bond joint between the

blade tulip

and the
composite interface.  To date, no blades have come

free, but

nine slips
is enough for the FAA to be concerned that somebody

might

throw at least
part of one blade and possibly have a bad day.  The

AD calls

for a one-
time rework of the blades and a change to the part

number.

   NOTE: AVweb's NewsWire <http://avweb.com/n/?01b>

includes

the
   complete text of the Airworthiness Directive

affecting

Hamilton
   Sundstrand propellers.

We need to see how they attach the composite blade to

the metal shank.

Several pretty competent engineering types believe

that the LAEV

attach method will work, but, hey, we can be all

wrong.  This is why

the prototype will be torture tested on a moving test

stand before we

build a second iteration.

If they're method is similar to ours we need to

understand what their problem

is and avoid duplicating it.

Bill Freeman
Long EZ builder & pilot
BSME, MSME
EAA Technical Counselor

Hi Paul/Guys;

Bill I agree!.........As I've mentioned numerous times
before, the bonding of the Composite to the steel Shank
is the ONLY thing that bothers me about the LAEV, and it
scares the S--T out of me.............We Damn-Well
better investigate and test this VERY VERY thoroughly.

In reference to the LAEV Prop assembly:
I had recently made a comment that I might experience
difficulty with the installation of the Snap-Rings, to
paraphrase it, "They might be a Bear to install", well
they are actually 2 BEARS, so get this, the manufacturer
simply recommends that a heat treated conical bushing
should be used for its installation!!??.......F--K THEM!
I've replaced them with double Spiral Rings, they cost
more but they are definitely easier to install.

Will be resuming assembly tomorrow and will be reporting
in to all.

                                     Butch

Hey guys if a Warp Drive and IVO prop can almost live on a Lycoming
we are home free :-)>

Paul Lamar
 
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