Prop to High RPM on downwind

Mitty wrote:
I like the several suggestions that the go-around mantra be "everything
forward" -- in fact I wish I had been drilled on that one while training
for my Private.

It's an okay mantra, but you probably want to make sure that you don't
have it so drilled in that you push the mixture full forward on a go
around at a high altitude airport.

--
David Rind

"Mitty" wrote

In the Six, which has a three-blade prop, I have to carry more power of
course.
Next time I fly it, I am going to listen more carefully while flattening
the
prop on downwind and see if there is much noise effect.


You, as a pilot, are in a bad place to observe prop noise, since 98% of the
extra noise comes off the prop, at high RPM, only in the plane of the prop,
or another way of saying it, is, right off the ends of the tips.

But you already knew that, didn't you? g
--
Jim in NC


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.799 / Virus Database: 543 - Release Date: 11/19/2004

try setting up your pattern so you arrive 1500 feet above field elevation
when abeam the approach end of the runway

No thanks. Especially not in a low wing airplane. I'll stick with the orthodox
pattern. I don't mind steep approaches, but I do mind descending onto someone
who is following the rules.

You, as a pilot, are in a bad place to observe prop noise, since 98% of the
extra noise comes off the prop, at high RPM, only in the plane of the prop,
or another way of saying it, is, right off the ends of the tips.

But you already knew that, didn't you? g

Actually, no. But whatever the level to others, it is probably proportional to
the level I get, no? So I can still make the judgement call.

David Rind wrote:

Mitty wrote:
I like the several suggestions that the go-around mantra be "everything
forward" -- in fact I wish I had been drilled on that one while training
for my Private.

It's an okay mantra, but you probably want to make sure that you don't
have it so drilled in that you push the mixture full forward on a go
around at a high altitude airport.

That's just another good reason why a "flow-check" involves thinking.
Letting it become too automatic is a Bad Thing. Oddly enough grin.

- Andrew

Icebound wrote:

Do not high-volume airports prefer "local procedures" that encourage
cruise or near-cruise for the small types until just about base turn, just
to keep the traffic from backing up???

I don't know about it being as well-defined as a "local procedure", but I've
been told to keep the speed up on final at some airports in the past
(Teterboro comes to mind). That's not always the best choice, though, and
I'm sure ATC knows it. On approach into Albany last week, I was able to
turn off quite early. If I'd been told to keep my speed up, I'd have
floated much farther.

Keeping the speed up is actually fun at the airports where it happens, as
there's plenty of runway for a slow-motion flair.

- Andrew

Following what rules? Downwind, base and final? Everything I described,
just closer to the airport.
By flying the approach I described, you will always reach the runway.
Flying a wide pattern and pushing the power/prop up and hearing the
engine make a strange sound may not get you where you want to go.

Mitty wrote:
try setting up your pattern so you arrive 1500 feet above field
elevation when abeam the approach end of the runway

No thanks. Especially not in a low wing airplane. I'll stick with the
orthodox pattern. I don't mind steep approaches, but I do mind
descending onto someone who is following the rules.

Exactly, except for those airplanes that cannot maintain level flight at
pattern speed with gear and flaps out at final descent power settings.

I fly downwind at 90 KIAS, 15" MP nice and level. Its a bit faster than Jim,
but a nice easy number to remember and consistent with everything else in
the pattern for the most part.


Which is, by the way, all airplanes with a constant speed prop. The power
setting for final descent is necessarily lower than that required for
level flight within the pattern, even if you slowed ALL the way to your
final approach speed. RPM will thus be higher, assuming the pitch is set
to full fine pitch (high RPM). Higher RPM means more noise.

Jim talked about speed not power. The point is that the power is already
reduced to the point where the Prop control does nothing (the prop is at its
stops) so pushing the prop control to fine pitch does nothing - the prop is
already at its finest pitch because the governor set it there trying to
maintain whatever RPM setting (say 2200) you had set for cruise - as you
reduce power it tried to keep the RPM up, until it couldn't make the pitch
any finer after which the RPM started to decline along with engine power.


If Jim's 182 flies along level in the pattern at the same airspeed and
prop RPM that he uses for final descent, I have no idea how he
accomplishes a final descent at all. A plane like that would be stuck up
in the pattern indefinitely.

No, he like everyone else reduces the power - sets the pitch to get the
airspeed he wants and the plane comes down - flaps help even more. The RPM
reduces along with the power (irrespective) of the position of the prop
control.

-Brenor

"Brenor Brophy" wrote in message
news
Jim talked about speed not power. The point is that the power is already
reduced to the point where the Prop control does nothing (the prop is at
its stops) so pushing the prop control to fine pitch does nothing - the
prop is already at its finest pitch because the governor set it there
trying to maintain whatever RPM setting (say 2200) you had set for cruise

I'm talking about power though, which is the point here. In my airplane, if
I push the prop control to full fine pitch while in the pattern, I will
require a significantly high RPM to have enough power to maintain level
flight at my pattern speed (which is, coincidently, the same speed I fly my
approach). Many airplanes have this characteristic.

Similarly, even in an airplane where the required power setting is
relatively quiet, you can still be even quieter if you pull the prop back
further. Who cares if your cruise setting was 2200 RPM? If you're trying
to fly friendly, then fly a power setting that slows the prop down even
more. 2000, 1800 RPM, whatever it takes to get that prop back off the stops
at your current power setting.

Bottom line: from level flight in the pattern, it requires a power reduction
to descend to the runway. If the prop is at fine pitch during that level
flight segment, it doesn't need to be, and you could reduce prop RPM (and
noise) even further. By doing so, you'll fly quieter and more efficiently
(not that efficiency really matters so late in the flight).

I recognize that many people call it "good enough" and don't bother to try
to get their airplane any quieter. But IMHO, it's pretty hypocritical to
claim to be in favor of not pushing the prop control to max RPM until the
power is set low enough, but to not be willing to minimize one's noise
footprint by reducing RPM in the pattern as well.

Pete

"Mitty" wrote in message
.. .

You, as a pilot, are in a bad place to observe prop noise, since 98% of
the
extra noise comes off the prop, at high RPM, only in the plane of the
prop,
or another way of saying it, is, right off the ends of the tips.

But you already knew that, didn't you? g

Actually, no. But whatever the level to others, it is probably
proportional to
the level I get, no? So I can still make the judgement call.

Actually, no. You just don't get the "blat" from the tips when you are
sitting behind them.
--
Jim in NC


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.799 / Virus Database: 543 - Release Date: 11/20/2004