"Larry Dighera" wrote in message
.. .
On Wed, 26 Jan 2005 14:43:35 GMT, "Jay Honeck"
wrote in q0OJd.29738$EG1.8340@attbi_s53::

We went through the prestart checklist, and I engaged the starter only
to hear a loud clunk as the first blade went by. He had left the tow
bar on the front gear leg.

I saw a guy do that once.

Hitting the tow bar may not damage the prop, but it sure would damage
whatever the tow bar hit.

We were fortunate. The tow bar remained attached to the gear leg. I
presume this meant that the cylinder failed to fire in the first 180
degrees of prop rotation.


On Thu, 27 Jan 2005 19:28:02 -0500, "steve" wrote
in ::

Hitting the tow bar would damage the prop enough to put any nick or stress
riser out of limits...a nick on the trailing edge would cause a chordwise
crack quite quickly...If i were flying that plane, I would refuse to fly the
aircraft until the prop was certified airworthy by at least a qualified
mechanic. A small scratch may seem irrelevant but at 9000g's it really is.

We examined the prop and the tow bar and were unable to discern any
nick, scratch nor evidence of any impact at all. Of course the
trailing edge of the propeller wasn't involved in our incident.

If you consider that a 4-stroke IC engine requires two revolutions to
complete one full combustion cycle, then it would seem there is one
cylinder firing each half turn of a four cylinder engine.

Fortunately it was just the power of the starter motor that powered
the propeller that (probably less than) half turn. If the engine had
been running or even if it had fired a cylinder in that first 180
degrees, we would have considered scrubbing the flight.

Incidentally, what's a "stress riser?"