Nasa Icing courses

"George Patterson" wrote

In the absence of some catastrophe, such as a bent pushrod, this is
generally caused by not flying enough.

Whenever I see less than 200 hours on an engine in a year, it seems like
there are tales of destruction of an engine to follow.

All of this would not be nearly as likely (it seems to me) if aircraft
engines were equipped with rollers on the cams.
--
Jim in NC

George Patterson writes:


"So why not build the shaft entirely of hardened steel?", I hear you cry. That's
because the harder steel is, the more brittle it becomes. The best strength
comes from this sort of lamination of hard and soft steels.

Saw a show w/ a Japanese craftsman making a sword. Two layers of
different steels. Pounded it thin; folded it over; pounded...
Many layers later, that was the sword...

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Sun, 08 Jan 2006 05:02:33 GMT, George Patterson
wrote:

In the absence of some catastrophe, such as a bent pushrod, this is generally
caused by not flying enough. The layer of hardened steel on a camshaft is fairly
thin. Let the plane sit long enough, and rust will form. When the engine starts
again, the rust is worn away, making the thin layer of hardened steel thinner.
The worst wear points, of course, are the tips of the lobes. Once the hardened
steel wears through, the softer steel underneath goes pretty rapidly.

The automotive world tried out roller lifters a long time ago. They
would work fine in aircraft engines too. I've heard that some of the
engines built for the homebuilt market can and do incorporate roller
lifters. I even thought I read that at least one company was
intending to certify such an engine.

Corky Scott

"Jay Honeck"

The intake cam lobe for the #3 and #4 cylinders failed and is worn down
considerably, hence the engine coming off and waiting for the crate.

I've been following your engine woes with great interest, Ray, and not a
small bit of horror. To say you are living one of my worst nightmares is
not far from the truth, and I feel your pain.

Does anyone *really* know what causes a camshaft to fail like this? I
read about it happening with alarming regularity, and it's never
attributed to anything in particular. It's always treated like an act of
God, or like a weather phenomenon, rather than like the mechanical failure
it is.

And mechanical failures should have simple explanations, no? WHY did one
of the cam lobes fail? Why didn't ALL of the cam lobes fail?

Timeless issue. www.aviationconsumer.com has hours of reading on the
subject. The common factor is infrequent flying.

moo

And mechanical failures should have simple explanations, no? WHY did
one of the cam lobes fail? Why didn't ALL of the cam lobes fail?

Timeless issue. www.aviationconsumer.com has hours of reading on the
subject. The common factor is infrequent flying.

I suppose the *real* issue should be: Why do camshafts work at all? When
you sit down and rationally analyze what is happening inside your engine,
the danged thing should just throw itself to pieces in the first ten minutes
of operation.

Yet, most of them don't.

Some, however, like Ray's engine, do -- and in very peculiar ways. (Just
ONE cam lobe went bad?)

Why?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I guess I understand now how you fellows and gals have
time to work on your airplane. Down here in sunny Texas,
it is almost always good flying weather, and given the choice
between flying and tinkering, I always seem to pick flying.

Ronnie

"Jay Honeck" wrote in message
news:24Hvf.682611$x96.306653@attbi_s72...
Hey... that little window let me fly home (Wisconsin-Virginia) on New
Year's
Day.... Take what you can get!

Hey, we flew VFR from Iowa City to Janesville, WI (and back) last Sunday.

The last 45 minutes were, um, interesting. The temperature and dew
points began to converge, as the sun began to set, and sky conditions
dropped from 11,000 broken to a very optimistic 1300 overcast -- across a
250 mile wide stretch of terrain -- in about 20 minutes. It was the most
widespread deterioration I've ever seen.

I was glad to be on the ground at the end of that flight. We were still
legal VFR, but visibility was 5 miles or less, and nasty icing was
occurring less than a thousand feet up.

Other than that, we haven't flown diddly squat in weeks. Our last fly-in
guest was sometime around Thanksgiving. Worst flying weather I've ever
seen.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"