My wife getting scared

Jay Honeck wrote:
So, I've seen scads of real-life experience that says that shock cooling
is just not real. The real part is people who don't practice engine-out
landings and then crumple an airplane botching the real thing.

I don't believe shock cooling exists, either. Or, if it does, it's
fairly insignificant.

But I do believe that repeated and sudden applications of full power
are harder on an engine than steady-state operation. Touch & goes
and engine out practice require this type of engine operation.

Engines have vibration and resonances that vary with RPM. Running at a
constant RPM for long periods of time causes a certain wear pattern on
certain parts. Varying RPM over time induces different vibration an
part resonances and spreads the wear over different areas. This isn't a
bad, bad, bad thing.

Matt

Matt Whiting wrote:
Engines have vibration and resonances that vary with RPM. Running at a
constant RPM for long periods of time causes a certain wear pattern on
certain parts. Varying RPM over time induces different vibration an
part resonances and spreads the wear over different areas. This isn't a
bad, bad, bad thing.

My mechanic echoed this also. I was told even in cruise that it's a good
idea to vary the RPMs every 10 minutes or so.

Shirl wrote:
Matt Whiting wrote:
Engines have vibration and resonances that vary with RPM. Running at a
constant RPM for long periods of time causes a certain wear pattern on
certain parts. Varying RPM over time induces different vibration an
part resonances and spreads the wear over different areas. This isn't a
bad, bad, bad thing.

My mechanic echoed this also. I was told even in cruise that it's a good
idea to vary the RPMs every 10 minutes or so.

I believe that is a good idea also. Constant RPM is great for engines
that will ALWAYS run at constant RPM (stationary generators, etc.).
However, for engines that must run across a range of RPMs, I believe it
is better to operate them across that full range as often as practical.

Matt

Engines have vibration and resonances that vary with RPM. Running at a
constant RPM for long periods of time causes a certain wear pattern on
certain parts. Varying RPM over time induces different vibration an
part resonances and spreads the wear over different areas. This isn't a
bad, bad, bad thing.

True enough. It is good for your engine to vary RPMs gradually and
gently.

In my experience, every mechanical thing last longer when treated
gently. This is why I (and others) take a full 3 or 4 seconds to
apply full power at take off, rather than simply slapping the throttle
lever to the stops. (I confess that I never worried about such things
as a renter...)

Young people -- especially young men -- take a long time to learn
this. (I know I did.) To illustrate this phenomenon, we need only
look at my riding lawn mower. For four years it ran perfectly with
me on board. This summer, my 16 (now 17) year old son took over the
hotel mowing duties. Within two weeks, the mower needed to be
repaired. Rough, abrupt usage of ANY mechanical equipment will
shorten its lifespan.

At the core I think we're talking about a matter of degree and
technique here. In my experience of doing engine out practice with
CFIs, we would get down to within a few hundred feet of the ground
(this in the wide-open Midwest, remember) and then quickly apply full-
power when we knew we had made (or not made) the chosen field.

I am going to try to practice them with a gentler technique next time
I fly.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:
In my experience, every mechanical thing last longer when treated
gently. This is why I (and others) take a full 3 or 4 seconds to
apply full power at take off, rather than simply slapping the throttle
lever to the stops. (I confess that I never worried about such things
as a renter...)

I do, too, but I did this as a renter, too. My dad was a carpenter -- he
insisted that we go easy on EVERYTHING! If we changed channels on the TV
"too fast", we were in trouble because that was considered "hard" on the
dial and the TV. Not to mention that everything in life generally
responds better when treated gently and with respect rather than being
manhandled!
;-)

Young people -- especially young men -- take a long time to learn
this. (I know I did.) To illustrate this phenomenon, we need only
look at my riding lawn mower. For four years it ran perfectly with
me on board. This summer, my 16 (now 17) year old son took over the
hotel mowing duties. Within two weeks, the mower needed to be
repaired. Rough, abrupt usage of ANY mechanical equipment will
shorten its lifespan.

I think part of this is learned and sinks in more once you start paying
for your own stuff and its associated maintenance out of your own
pocket, with money YOU have earned!

In my experience, every mechanical thing last longer when treated
gently.

Young people -- especially young men -- take a long time to learn
this.

I think part of this is learned and sinks in more once you start paying
for your own stuff and its associated maintenance out of your own
pocket, with money YOU have earned!

A friend of mine, whose four kids were all a little older than my four
kids, told me his car maintenance and repair bills had gone up 25% when
his kids began to drive. He said a mechanic told him that was typical.

Learning from his experience, I told my kids that when they began to
drive, they would have to pay the additional insurance premium, plus
their share of gas, oil, and maintenance.

When they discovered the incremental insurance alone was about $160 per
year, they decided they really didn't want to drive after all.

One benefit of that is that they are all still alive.

vince norris