Proping Question

On May 15, 5:59 am, "Doug Palmer" wrote:
Several pilots found themselves in a debate at our field yesterday. The
issue is weather it is safer to move the propeller on a (parked) aircraft in
the direction of usual engine rotation, or opposite usual rotation. This is
assuming that the propeller needs to move for some reason.

The reasonings ranged from "you should not turn an engine backwards" to
"turning the engine backwards disarms the impulse coupling", to several
issues in between.

Any thoughts from the groups collective wisdom?

Of course turning it backward may damage the vac pump but I've never
flown a hand prop'ped airplane that had a vac system.
The problem with turning it backwards is that it can still on forward.
If you turn it and stop near the compression, it will then turn back
the other way. So, either way assume its hot.
Once you've been flying a hand propped airplane for awhile you will
realize that it is not safe or reasonable to use a full body kick
every time you turn the prop. So I would pull the prop through with an
open palm hand such that if the prop did start I would be ok (some of
the old guys actually start the plane this way). Then, when its time
to start, I hit the mags and do a full kick. If you primed the engine
correctly it should only take about an 1/8 of a turn for it to fire.
BTW: I would never hand prop a nosewheel plane.

-Robert

Robert M. Gary wrote:
BTW: I would never hand prop a nosewheel plane.

Personally, I wouldn't hand prop any plane. I got too many nicks and
cuts as a kid finger propping model airplanes. (-:

Which reminds me of a story. One winter a few years ago the FBO had a
152 that was being stubborn in the cold weather, so one of the line guys
helped out by hand propping it for the pilot. He was wearing gloves and
when the plane started, one of his gloves came off. The prop threw the
glove about 30 feet and the pilot freaked out because he thought the
guy's hand was still in the glove! He shut the engine down to check on
him. The line guy wasn't happy about having to hand prop it again...


-m
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Robert M. Gary wrote:
BTW: I would never hand prop a nosewheel plane.


Just out of curiosity, why does a nosewheel make a difference?

I used to have an old 172 (with the cheesey 20 amp generator) that required
a handprop after most night flights. I didn't seem any different than
handpropping a tailwheel equiped 170.

John Galban=====N4BQ (PA28-180)

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"Robert M. Gary" wrote

BTW: I would never hand prop a nosewheel plane.

I think I know the reason for this opinion, but I would still be interested
in hearing your reasoning.

Why no hand propping a nose dragger for you?
--
Jim in NC

On May 15, 2:47 pm, "Morgans" wrote:
"Robert M. Gary" wrote

BTW: I would never hand prop a nosewheel plane.

I think I know the reason for this opinion, but I would still be interested
in hearing your reasoning.

Why no hand propping a nose dragger for you?

Because the top arch of the prop is close to my head. When teaching
students to hand prop the biggest challenge is to get them to stand
close enough to the prop. Standing too far back is much more dangerous
than standing too close. The worst thing that could happen is to fall
into the prop, something that can only happen if you are standing back
and leaning into it.

-Robert

"Robert M. Gary" wrote

Because the top arch of the prop is close to my head. When teaching
students to hand prop the biggest challenge is to get them to stand
close enough to the prop. Standing too far back is much more dangerous
than standing too close. The worst thing that could happen is to fall
into the prop, something that can only happen if you are standing back
and leaning into it.

I was wrong. I had not heard that exact variation, before. g

Kicking though is still too close, even if you are swinging your body away
from the tip?
--
Jim in NC

Kicking though is still too close, even if you are swinging your body away
from the tip?

What exactly is "kicking"?

Jose
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On Thu, 17 May 2007 04:05:57 GMT, Jose
wrote:

Kicking though is still too close, even if you are swinging your body away
from the tip?

What exactly is "kicking"?

You're facing the prop from the front ot the plane. The blade is at
10 o'clock, at the start of a compression stroke,. You've previously
primed the engine and pulled the prop through several compressions
with the switch cold and the mixture rich.

Now you holler "Hot!, Brakes!" (assuming somebody's in the cockpit --
otherwise you switch the mags to hot and check the chocks and tiedown.

Reach up, pads of your fingers just over the top of the blade. Left
leg on ground, right leg swings forward and smartly back at the same
time that you snap the blade down. The leg swing propels your body
backward, away from the propeller arc.

That was the drill on the Taylorcraft. Cub pilots can swing the prop
from behind because of the way the doors work. I guess you'd have to
prop a T-craft on floats from behind, too, but it wouldn't be pretty
to look at.

It took the lady who sold me the plane about ten minutes to teach it
to me. It feels kinda natural. If it's a big exertion, you're doing
it wrong.

Don

On Wed, 16 May 2007 21:39:54 -0700, Don Tuite
wrote:

Now you holler "Hot!, Brakes!" (assuming somebody's in the cockpit --
otherwise you switch the mags to hot and check the chocks and tiedown.

With me, it's BRAKES! CRACKED! (referring to the throttle), HOT!

Reach up, pads of your fingers just over the top of the blade. Left
leg on ground, right leg swings forward and smartly back at the same
time that you snap the blade down. The leg swing propels your body
backward, away from the propeller arc.

Huh. With me it's the left leg that swings. Then the right leg turns
me farther back and to the left, out of the propeller arc.

Blue skies! -- Dan Ford

On May 16, 3:05 pm, "Morgans" wrote:
"Robert M. Gary" wrote

Because the top arch of the prop is close to my head. When teaching
students to hand prop the biggest challenge is to get them to stand
close enough to the prop. Standing too far back is much more dangerous
than standing too close. The worst thing that could happen is to fall
into the prop, something that can only happen if you are standing back
and leaning into it.

I was wrong. I had not heard that exact variation, before. g

Kicking though is still too close, even if you are swinging your body away
from the tip?
--
Jim in NC

In a tailwheel, as you pull the prop "down" during the kick you are
also moving toward yourself (because of the angle the taildragger sits
on the ground), which helps you maintain contact as you are moving
away from it. In a nose wheel plane you'd be pushing straight down on
the prop, causing your head to move down closer to the prop arch.

-Robert