John,
Beg to differ.  I'm agreed that there are a lot of variables and we should examine as many as we are able and that "dumb luck" might be considered as an explanation for aberrations from patterns.  That said, 6" of exhaust is 6" of exhaust.  Nobody's exhaust is soft or plastic or aluminum.  They're mostly about the same weight, distance from the hub (I would guess my Velocity exhaust would hit the prop a little farther from the hub than DD's), etc.  Mine hit edge first (so as to dig the deepest gouge in the leading edge of the prop) on the first blade, and pretty much cross ways on the second.  Craig says there have been a number of exhaust incidents, ALL as benign as mine, and one of his customers had the ENTIRE LOWER COWL from a Long-EZ go through his prop and the airplane flew home under power.

I've had wooden props on my EZ that got nearly as dinged up with an errant cowl screw as the Catto unit did with the exhaust pipe, and much MUCH worse from a 3" x 6" piece of .020 SS that hit much closer to the hub.  I do give credit to the LE protective tape for helping out some in minimizing the damage, but it did NOT "save" the prop.  It's clear to me that it was the composite construction did that.

I know you have a Performance prop, and we have only two data points that we are really familiar with.  I would suggest that if there were lots of data points and my experience was easily the most benign, then we could talk about pure "dumb luck".  But that should be the last explanation put forth, not the first.  Absent evidence of dumb luck or other compelling factors, anecdotal evidence rules.

I will ask Craig Catto to elaborate on incidents involving his products.  Why don't you talk to the Performance folks about their experience?

I think this issue is important enough to warrant some research .... Jim S.
 

John Slade wrote:

Jim,
I think you're WAY off mark here. When you're bored one day, try throwing
things at a you're ceiling fan. Sometimes you'll be lucky sometimes you
won't.

When something comes off an engine and hits a prop (ANY prop) there are lots
of variables at work which determine the damage that's going to be caused.
The item involved, the RPM at the time, the exact impact angle and position
of the prop at the second the item hits it, and pure dumb luck come to mind
as just a few.

No offense to Craig Catto and his excellent products, but I'd suggest that
the latter is the main reason for the end results in both you're case and
Dave Domier's.
Regards,
John

>>  Homepage:  http://www.flyrotary.com/
>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html

--
Jim Sower
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T