On Fri, 29 Jan 2010 10:08:07 -0800 (PST), Oliver Arend
wrote:

Inspired by a couple of articles on Bob Hoovers blog and the fact that
it's likely that my first homebuilt will be slow and VW-powered, I was
thinking of making a wood propeller.

There is an australian company in bundaberg that sells a propeller
made from Queensland Hoop Pine.

at one of our flyins a friend was walking around asking everyone where
the bushfires were to the north of the airfield. he could sure smell
them but he couldnt see smoke or fire but guessed that we were all in
for a busy fire season.
everyone looked at him and went "huh??"
fact is that there were no fires in new south wales that day.

one of the guys asked "have you got a wooden prop?"
"yeah a new &&&&&&& prop, I swapped out the old one yesterday"
"we'd better have a look at your prop!, got tools?"
"nuh, bit overloaded as it is"

one of the guys grabbed his aircraft tool roll and we gathered by his
canard dragonfly.
there was ceratinly a bushfire smell near that prop.

when the prop came off the rear face of the hub was charred to a depth
of about quarter of an inch.

the analysis was that the hoop pine lacks the compressive strength to
make a good propellor wood. evidently all the props made in queensland
hoop pine eventually fail in the hub area to either crushing or
charring.

friend hurridly phoned a mate who was departing later that day and got
him to bring the old prop with him, so it became a non event.

the crush strength of the wood in the hub area is likely to be the
critical factor in selecting the wood species used for a propeller.

(gads an interruption I cant dodge. I'll continue this in another post
after I get clear. back soon.)
Stealth Pilot