On Sun, 27 Jun 2004 13:05:33 GMT, "Jay Honeck"
wrote:

Interesting work, Kent. Thanks for doing it.

Any word on the O-540s? A 3-blade is in our future, if (when) our 2-blade
needs to be over-hauled.

But only if it doesn't change the vibration for the worse!


I did a bunch of "research" (asking as many 235 owners as I could
find) about this two years ago when one of my blades failed
inspection. Almost all of them reported some sort of vibration. Many
thought it was insignificant, but many thought it was worrisome. A
couple returned the new prop because they really didn't like it. I
took the approach that additional vibration no matter how minor is
un-needed. It could do nothing to the aircraft, or it could do
something, either way a small plane is noisy enough and has enough
vibration that I didn't want to add anymore, and my luck would be that
I'd have the same violent tail vibration one guy reported. No Thanks.

Other things I didn't like about the 3 blades were the fact that they
are a new "plastic" (carbon composite) type of material. No one knows
for sure what UV does to them. We may see some interesting stories
over the next 10 years if they don't hold up real well. Again its a
debate. Some people say composites are fine, some people say they
will become problematic. Until a 10 or 20 year study shows real
documentation it's all a matter of opinion. Also no ADs have been
issued for these yet (although many blades were scrapped before use
due to a bad production process). I like knowing that my prop
probably won't have any real expensive ADs issued against it. Since
its been in use for so long we generally know the limitations. (I
know once again a subjective opinion). With the composites I just
think a big surprise might be around the corner.

The last thing is that the 3 blades really kill your glide
performance. Almost everyone agreed on this one. My 235 already
leaves a little to be desired at best glide speed, why would anyone
want to shorten it even more? I know you can use the prop control to
overcome some of that, but what if you need to go-around for some
reason, you've got one more (critical) thing to do. The performance
gains on the other side didn't seem significant enough to me to
balance this out. Very slightly better climb performance an no one
reported better cruise.

When all was said and done I spent about 5Gs to do my governor, buy a
blade and have everything put back together. It would have been about
10 for the 3-blade. When I looked at the extra money, and some of the
downsides/unknowns. I kept the extra money in my pocket.

Hope this helps, I kind of streamed my thought process.

z

P.S. Glad you got some momentum behind your airport.