Nasa Icing courses

On Sun, 08 Jan 2006 13:45:12 GMT, Jay Honeck wrote:

Or, put another way, it's four 1-hour hamburger flights per week, every
week, all year long...

Is this slightly low Jay? 1/2 hour each way? My hamburger runs are
minimum 1 hour each way, which would reduce it to 2 hamburger flights per
week.

You are right, 200 hours a year is an awful lot of flying. You had me
curious for me, how much in a year I fly, and it was as follows:

2001 11.7
2002 49.5
2003 142.2
2004 192.9
2005 126.4
2006 4.0

I try to fly once a week at minimum myself and no less then one hour air
time when I fly.

I was told ground runs is one of the worst things you can do to an airplane
engine, as it was designed for sustained high RPM operations, not ground
run RPMS.

Allen

It is to do with air flow, you don't get proper cooling and
crankcase ventilation is very poor on the ground.

After landing, cool down is as important as warm up,
particularly with a turbocharged engine.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"A Lieberman" wrote in message
...
| On Sun, 08 Jan 2006 13:45:12 GMT, Jay Honeck wrote:
|
| Or, put another way, it's four 1-hour hamburger flights
per week, every
| week, all year long...
|
| Is this slightly low Jay? 1/2 hour each way? My
hamburger runs are
| minimum 1 hour each way, which would reduce it to 2
hamburger flights per
| week.
|
| You are right, 200 hours a year is an awful lot of flying.
You had me
| curious for me, how much in a year I fly, and it was as
follows:
|
| 2001 11.7
| 2002 49.5
| 2003 142.2
| 2004 192.9
| 2005 126.4
| 2006 4.0
|
| I try to fly once a week at minimum myself and no less
then one hour air
| time when I fly.
|
| I was told ground runs is one of the worst things you can
do to an airplane
| engine, as it was designed for sustained high RPM
operations, not ground
| run RPMS.
|
| Allen

I was told ground runs is one of the worst things you can do to an airplane
engine, as it was designed for sustained high RPM operations, not ground
run RPMS.

You know, I've heard that since Day One of ownership, too, but ya just
gotta wonder if it's not yet another "old wive's tale", like so many of
these "tried and true" things. How does the engine know the
difference between ground runs at, say 2000 RPM (run-up speed on our
plane) and an extended descent? Is *that* "bad" for the engine, too?

Doesn't running it for 30 minutes on the ground circulate the oil, and
prevent corrosion? Can't you get oil temps up to 150 or better (I
know, 180 is optimal, but...) with a ground run? Isn't that better
than letting it sit and rot till spring?

I fly too often for this to really matter, but I always wonder if it's
a real issue or not? Kinda like "shock cooling" and "pulling the prop
through" before starting on a cold day... And Marvel Mystery oil,
while we're at it...

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

In article .com,
"Jay Honeck" wrote:

I was told ground runs is one of the worst things you can do to an airplane
engine, as it was designed for sustained high RPM operations, not ground
run RPMS.

You know, I've heard that since Day One of ownership, too, but ya just
gotta wonder if it's not yet another "old wive's tale", like so many of
these "tried and true" things. How does the engine know the
difference between ground runs at, say 2000 RPM (run-up speed on our
plane) and an extended descent? Is *that* "bad" for the engine, too?

consider the difference in cooling air.

--
Bob Noel
New NHL? what a joke

Ground running does not scavenge the vapors since the vent
system depends on airspeed.



--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Jay Honeck" wrote in message
oups.com...
| I was told ground runs is one of the worst things you can
do to an airplane
| engine, as it was designed for sustained high RPM
operations, not ground
| run RPMS.
|
| You know, I've heard that since Day One of ownership, too,
but ya just
| gotta wonder if it's not yet another "old wive's tale",
like so many of
| these "tried and true" things. How does the engine know
the
| difference between ground runs at, say 2000 RPM (run-up
speed on our
| plane) and an extended descent? Is *that* "bad" for the
engine, too?
|
| Doesn't running it for 30 minutes on the ground circulate
the oil, and
| prevent corrosion? Can't you get oil temps up to 150 or
better (I
| know, 180 is optimal, but...) with a ground run? Isn't
that better
| than letting it sit and rot till spring?
|
| I fly too often for this to really matter, but I always
wonder if it's
| a real issue or not? Kinda like "shock cooling" and
"pulling the prop
| through" before starting on a cold day... And Marvel
Mystery oil,
| while we're at it...
|
| :-)
| --
| Jay Honeck
| Iowa City, IA
| Pathfinder N56993
| www.AlexisParkInn.com
| "Your Aviation Destination"
|

Jay Honeck wrote:

You know, I've heard that since Day One of ownership, too, but ya just
gotta wonder if it's not yet another "old wive's tale", like so many of
these "tried and true" things. How does the engine know the
difference between ground runs at, say 2000 RPM (run-up speed on our
plane) and an extended descent? Is *that* "bad" for the engine, too?

I've wondered that myself. The only big difference that I can think of is that
the circulation of cooling air will be different. As far as long descents is
concerned, I've seen statements that this is harmful due to excessive cooling
and possible plug fouling. Never seen a claim that oil circulation suffers, though.

Doesn't running it for 30 minutes on the ground circulate the oil, and
prevent corrosion? Can't you get oil temps up to 150 or better (I
know, 180 is optimal, but...) with a ground run? Isn't that better
than letting it sit and rot till spring?

As several others have pointed out, circulation of the oil isn't the problem
with the cam lobes. Those are lubricated by splash from the crank. I've never
seen any claims that this differs much from splash while in flight, though.

What I've read is that you really can't get the oil temperature high enough by
running it on the ground. The claim is that ground running adds water and acids
to the oil (flying also does this) and never gets the oil hot enough to vaporize
these. Crankcase ventilation through the breather is also very poor on the
ground; as a result, vapors that do form never leave the crankcase. As another
poster suggested, some form of positive crankcase ventilation would probably
help that.

If the only real issue proves to be the buildup of pollutants in the oil from
ground running, then changing the oil after every other run would take care of
the problem; however, given a choice between this and simply flying the plane
for a few hours, I'd be in the air.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.

On Mon, 09 Jan 2006 16:10:22 GMT, George Patterson
wrote:

As several others have pointed out, circulation of the oil isn't the problem
with the cam lobes. Those are lubricated by splash from the crank. I've never
seen any claims that this differs much from splash while in flight, though.

I actually thought this was a joke when I read it in a previous post.
You mean to tell me that the cam REALLY gets it's lubrication from
splash?

The crankshaft has to whip it's throws into the oil in the oil pan so
that the oil gets whipped around inside the engine and THAT's how the
cam gets oiled?

Lordy, thought that technology went out with Model T's

I can't think of a single engine in the automotive world that depends
on splash oil to lubricate anything.

No wonder auto oil is not supposed to be used in airplane engines.

Corky Scott

On 1/18/2006 11:44 AM, wrote the following:
On Mon, 09 Jan 2006 16:10:22 GMT, George Patterson
snip

I can't think of a single engine in the automotive world that depends
on splash oil to lubricate anything.


Hmm ... In every engine I've ever assembled the cam lobes running against the
tappets are splash oiled. In pushrod motors the rocker arm noses running
against the valve stems are splash oiled. Also the timing chain(s), the
distributor drive gear, ... Pretty much it is only the bearings that are
pressure oiled. i.e., mains, rods, cam(s).

YMMV, of course.

On Wed, 18 Jan 2006 13:40:21 -0600, Mitty wrote:

In pushrod motors the rocker arm noses running
against the valve stems are splash oiled. Also the timing chain(s), the
distributor drive gear, ... Pretty much it is only the bearings that are
pressure oiled. i.e., mains, rods, cam(s).

The engines pushrod engines I've assembled had hollow pushrods and fed
pressurized oil to the rocker arms. The rocker arms were hollow and
injected oil onto the valve stem to assist in cooling. Yes, the top
of the valve stem did not have any direct injection so it did require
splash oil for it's lubrication. That's where roller rockers help.

Guess I hadn't thought that much about it for a long while. I stopped
working as an auto mechanic a long time ago.

Corky Scott

How does the engine know the
difference between ground runs at, say 2000 RPM (run-up speed on our
plane) and an extended descent? Is *that* "bad" for the engine, too?

I'm guessing, but in an extended descent, the engine was already running
full bore for a while and is nice and hot and happy. In a ground run,
the engine probably started out cold and never got hot and happy.

Jose
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.