My wife getting scared

My mechanic -- a guy with over 40 years of experience as an IA, A&P,
grand champion home builder, and owner of an engine and prop shop --

Is he a pilot? airplane owner?

He's an expert pilot, and a very experienced owner. He has hand-built
several airplanes from scratch -- no "kit planes" for him. (His next
project will be to recreate -- from photos only -- a 1916 aircraft
that flew out of Grinnell, IA.)

They make it to TBO because they are flown many hours per week, the
numbers add up fast, and they are monitored, inspected and maintained
every 100 hours (which might be every other month) ... not simply
because flying them every day enables the engine to withstand doing the
"worst" possible thing 75% of the time it is in use.

Correct. That's what I was aiming to say, even it if didn't come out
quite right.

And you do half of that every time you take off and land. That doesn't
damage your engine, but the one extra application of power during a
touch-n-go or go-around is going to do your engine in?

Well, your engine has a limited number of those cycles in it. It's
the same thing I explain to my 17 year old son: Yes, you can floor
the car and spin the rear wheels a certain number of times, without
harming the engine. Sooner or later, though, that kind of treatment
*will* break something.

Airplanes are no different. Cycling from full power to idle is just a
bad thing to do with your engine.

Plenty of people practice touch-n-goes in their own airplanes ... if
they are THAT damaging to an engine, we'd be hearing of this engine
damage all the time. People with Cubs or other small tailwheels are out
doing touch-n-goes ALL THE TIME...doesn't seem to bother their engines.

Is this damage something you can quantify? When my buddy's engine
crapped out 700 hours before TBO, was it directly attributable to his
doing a zillion touch & goes?

I don't know, but I can safely say that if he had simply let his
engine run at a steady-state 2200 RPM, it would still be running
today. THAT is an indication of the wear and tear inherent with full
power/idle power engine management, versus cruise flight.

I understand and agree about inactivity and that most privately-owned
airplanes aren't flown enough. But you're saying that an engine that
flies for 8 hours/month and does touch-n-goes/engine-out practice during
ONE of those hours is more likely to be damaged than an engine that
flies 80 hours a month and does the damaging maneuvers during 60 of
those hours. If it's THAT bad, subjecting it to 60 hours a month would
still take a heavy toll even it flies every day.

I would agree with that. Full power/idle power cycles are very hard
on engines -- and that is what you're doing in a touch & go.

In fact, wasn't part of your training getting so familiar with
the airplane that you know how it acts and reacts to as many different
conditions/configurations as possible? How can you do that if you're
afraid that touch-n-goes or simulated engine failures are going to ruin
the engine?

Touch & goes aren't necessary to practice after your first 1000 or so
landings, IMHO. If you don't have it down pat by then, a few more
T&Gs isn't gonna help, and the beating your plane takes during the T&G
process is something to be avoided.

That's why airplane ads say stuff like "Never used as a trainer."

Engine out practice IS a good thing to do, however, and is why I do
feel badly about my reluctance to do them. I'm thinking maybe we'll
do some next time we go up, maybe at reduced (not idle) power...

I've never seen anything in my engine documentation that says it was
designed to be run every day.

Optimally, in order to run the longest possible number of hours, you
would never shut the engine off. I'll bet a Lycoming could run 10,000
hours easily if all you did was keep it running at 2000 RPM, and keep
adding oil and gas.

But that's not "real world". Looking at trainers at big flight
schools, they usually fly daily, often for many hours per day. And
they usually get some pretty impressive time on their engines that
way. (Hours-wise, not calendar-wise, of course.)

I just spent at least that much, too, and I'm sure as heck not going to
intentionally abuse the engine. But I'm not going to skip some aspects
of ongoing skill retention drills that I've seen the pay off firsthand
in an emergency because I'm thinking about the $20K I just spent.

Yep, I agree. You're the voice of experience here, which is why I'm
engaged in this thread. I *am* worried about not practicing the
procedures enough, but I just don't want to shorten the lifespan of a
very expensive engine needlessly...

In skating, we used to teach students that they could expect to lose up
to 25% of their actual ability/competence during their 4 minute routine
in a competition due to nerves and pressure; so if they wanted to show
the judges 100% of their capabilities, they have to be skating at 125%
in the weeks prior to the competition. I don't know if those numbers
translate to flying, but I think the concept itself does. I would hate
to lose a percentage of my ability in an actual emergency if I was only
at 80% to begin with. YMMV, of course. Everyone's different.

Agree. Staying sharp is your best defense.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:
He's an expert pilot, and a very experienced owner. He has hand-built
several airplanes from scratch -- no "kit planes" for him. (His next
project will be to recreate -- from photos only -- a 1916 aircraft
that flew out of Grinnell, IA.)

Cool. Sounds like an interesting, knowledgeable guy.

Well, your engine has a limited number of those cycles in it. It's
the same thing I explain to my 17 year old son: Yes, you can floor
the car and spin the rear wheels a certain number of times, without
harming the engine. Sooner or later, though, that kind of treatment
*will* break something.

Airplanes are no different. Cycling from full power to idle is just a
bad thing to do with your engine.

The engine was designed with the knowledge that in order to fly, the
transition from full power to idle will have to be made at some point
.... that in itself is not "a bad thing". If that's ALL you're constantly
doing in every flight, then yes, I would agree with you, but that isn't
what I meant by practicing simulated engine failures more often than
every other year (during BFRs). Certainly a healthy engine can do them
more often than that without being damaged.

When my buddy's engine crapped out 700 hours before TBO,
was it directly attributable to his doing a zillion touch & goes?

Maybe, maybe not.
But again, I wasn't talking about doing a zillion touch-n-goes, I was
talking about practicing simulated engine failures often enough that
*IF* the real thing occurs, you don't waste several precious seconds
reacting, trying to remember the drill, or make any mistakes because you
(not you personally) haven't flown enough power-off approaches/landings
in the airplane you always fly.

I don't know, but I can safely say that if he had simply let his
engine run at a steady-state 2200 RPM, it would still be running
today.

No, you can't. Not doing touch-n-goes is not a guarantee that any engine
will make it to TBO or still be running. It's hard to make ANY
guarantees where engines are concerned...we do what the experts we know
and respect recommend, and hope for the best, but even they don't make
guarantees.

THAT is an indication of the wear and tear inherent with full
power/idle power engine management, versus cruise flight.

I'm not disagreeing that there is wear and tear involved. But again, I
also was not talking about a plane that ONLY does touch-n-goes. Of
course cruise flight should make up the bulk of the time.

Touch & goes aren't necessary to practice after your first 1000 or so
landings, IMHO. If you don't have it down pat by then, a few more
T&Gs isn't gonna help, and the beating your plane takes during the T&G
process is something to be avoided.

It isn't a matter of "having it down pat" -- most of us have landings
down fairly pat by the time we get our ticket. But just because a person
has done 1000 landings doesn't mean it's never necessary to practice
touch-n-goes. Is there anyone who flies religiously once- or
twice-a-week *without fail*, FOREVER? If so, they likely don't have to
practice touch-n-goes. But who hasn't had to be off for a month or more
once in a while due to other priorities in life or when a mechanical
issue takes a month or more to resolve? When you get back in the air
after a long period off, are your approaches and landings just as sharp
as ever? If so, kudos to you! I'm not a professional pilot, and mine
aren't always as good as they could be after I've been off for a month
or more, and in those instances, three or four touch-n-goes is usually
just what the doctor ordered. And once again, I'm not suggesting that
EVERY flight should consist of touch-n-goes or include an engine-out
practice.

That's why airplane ads say stuff like "Never used as a trainer."

That's not the only reason. "Trainers" take a lot more forms of abuse
than just touch-n-goes.

Engine out practice IS a good thing to do, however, and is why I do
feel badly about my reluctance to do them. I'm thinking maybe we'll
do some next time we go up, maybe at reduced (not idle) power...

Good. As a friend, I'm glad to hear that.

Optimally, in order to run the longest possible number of hours, you
would never shut the engine off. I'll bet a Lycoming could run 10,000
hours easily if all you did was keep it running at 2000 RPM, and keep
adding oil and gas.

My mechanic was at my hangar this morning. I was picking his brain about
this stuff. He said an airplane should be flown *at least* once a week
to keep condensation/corrosion away (and other reasons but that being
most important). He said Lycoming documentation actually states that an
engine should be preserved (pickled) if it isn't going to be flown for
10 days or more, although no one does that. I've heard of pickling in
extreme temps (cold) when not being flown *for an entire season*, but
even then, seems a lot of people just let them sit.

The person in the hangar across the taxiway from me was there for the
first time this morning -- I'd never even seen or met him in the entire
time I've been there. He said he hasn't flown in 2 years, and his C-180
hasn't either. It's having an annual now and he's about to begin flying
again. It was not pickled, and I'll be interested to hear what was done
in this annual, with that in mind. (I didn't ask why he was off for 2
years...guessing it might have been a medical issue.)

But that's not "real world". Looking at trainers at big flight
schools, they usually fly daily, often for many hours per day. And
they usually get some pretty impressive time on their engines that
way. (Hours-wise, not calendar-wise, of course.)

We had a C-152 at our flight school. It had 13K hours on it when I got
my ticket in it, and while it had its own little quirks, it obviously
had been reliable. It was nearing 14K hours when a customer had an
emergency, landed in the desert, flipped it onto its back and totaled
it. Thankfully, they walked away. It had been a reliable, fun little
bird. I do not know how many overhauls it had or if it went to TBO each
time, but considering how much abuse it took doing T&Gs, spin training,
being khablammed by people learning to land, and who-knows-what else
customers put it through, it served everyone well and did Cessna proud.

I just spent at least that much, too, and I'm sure as heck not going to
intentionally abuse the engine. But I'm not going to skip some aspects
of ongoing skill retention drills that I've seen the pay off firsthand
in an emergency because I'm thinking about the $20K I just spent.

Yep, I agree. You're the voice of experience here, which is why I'm
engaged in this thread. I *am* worried about not practicing the
procedures enough, but I just don't want to shorten the lifespan of a
very expensive engine needlessly...

Yeah, I hear ya. I just don't think an occasional simulated engine-out
practice is "needlessly".

Shirl

"Shirl" wrote:
but I just don't want to shorten the lifespan of a
very expensive engine needlessly...

Yeah, I hear ya. I just don't think an occasional simulated engine-out
practice is "needlessly".


And I still want to know *how* it harms the engine. Exactly what parts will
be damaged, and why?

--
Dan
T-182T at BFM

Yeah, I hear ya. I just don't think an occasional simulated engine-out
practice is "needlessly".

And I still want to know *how* it harms the engine. Exactly what parts will
be damaged, and why?

Can we agree that idle power/full power engine management will cause
more wear and tear (AKA: "Damage") to an engine than steady-state
operation?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote:

Yeah, I hear ya. I just don't think an occasional simulated engine-out
practice is "needlessly".

And I still want to know *how* it harms the engine. Exactly what parts
will
be damaged, and why?

Can we agree that idle power/full power engine management will cause
more wear and tear (AKA: "Damage") to an engine than steady-state
operation?

No, Jay, not until I know what the "wear and tear" is, and why increasing and
decreasing the power at short intervals causes it.

It's a serious question. Off-hand, I can't think why t&g engine operation
would be more harmful per hour than takeoff/cruise/land, as long as no
operating limits are exceeded.

--
Dan
T-182T at BFM

Jay Honeck wrote:
Yeah, I hear ya. I just don't think an occasional simulated engine-out
practice is "needlessly".
And I still want to know *how* it harms the engine. Exactly what parts will
be damaged, and why?

Can we agree that idle power/full power engine management will cause
more wear and tear (AKA: "Damage") to an engine than steady-state
operation?

I am not at all convinced that this is the case. Prolonged idling on
the ground probably isn't that good due to lack of cooling air flow, but
other than that, I don't think that varying the throttle from low to
high power settings necessarily causes any damage and I've read a fair
bit that suggests just the opposite.

Matt

Jay,

Can we agree that idle power/full power engine management will cause
more wear and tear (AKA: "Damage") to an engine than steady-state
operation?


No. Why?

--
Thomas Borchert (EDDH)

Can we agree that idle power/full power engine management will cause
more wear and tear (AKA: "Damage") to an engine than steady-state
operation?

No. Why?

I'm no thermodynamist, but I believe it's commonly accepted that
taking an internal combustion engine from steady state/low RPMs to
full power/high RPMs (as one would repeatedly do during touch & goes
and engine-out practice) is more harmful to the engine than simply
steady-state/mid-RPM power settings.

A rough analogy would be to think of drag racers versus rally car
engines. One lasts 20 to 30 seconds, the other lasts 1000 miles.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay Honeck wrote:

I'm no thermodynamist,

......and owning your own hotel, it's an odds on bet you didn't sleep at
a Holiday Express last night ether!!!!!!!
:-))
D

--
Dudley Henriques

"Jay Honeck" wrote:

A rough analogy would be to think of drag racers versus rally car
engines. One lasts 20 to 30 seconds, the other lasts 1000 miles.

That's *too* rough. Unlimited drag racers are blown to a jillion horsepower
and burning nitro. It ain't the cycles that breaks 'em, it's the internal
pressures.

I think you're just going on gut feeling, and you know...

Intestinologists concur that the human gut does not contain any
rational thoughts.

What the human gut *is* full of is moderately well
known.

--
Dan
T-182T at BFM