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Prop to High RPM on downwind



 
 
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  #51  
Old November 24th 04, 02:52 PM
Mike Rapoport
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"Peter Duniho" wrote in message
...
"Chris" wrote in message
...
[...]
With the 182, it is 80 knots turning from the 45 to downwind, 75 on
base, and 70
on final. I don't understand why pushing the prop to full flat has any
noise
effect whatsoever.


Exactly


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

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.

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.

Pete


Why would anyone want to fly around the pattern at a constant altitude with
gear and flaps out except on a circling approach? I was leave the gear and
flaps up until I want to descend. I was under the impression that virtually
everyone did it this way.

Mike
MU-2


  #52  
Old November 24th 04, 03:00 PM
Icebound
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"Jim Weir" wrote in message
...
Then I hope you won't take my offer of a free biennial next July. I
expect a
person to fly the same pattern from Anchorage to Dallas, no matter whether
they
are the only person in the pattern or #25 to land.

Certainly we can make allowances for situations, but if you are saying
that you
make different patterns when you are alone in the pattern, I'd suggest
another
instructor. I certainly won't sign you off.


Surely different pattern *speeds* in different conditions, does not imply
different *patterns*, does it?


  #53  
Old November 24th 04, 03:12 PM
Jay Honeck
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Certainly we can make allowances for situations, but if you are saying
that you
make different patterns when you are alone in the pattern, I'd suggest
another
instructor. I certainly won't sign you off.


Dang -- and here I was all set to fly to California for my biennial...

Spoil sport...

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


  #54  
Old November 24th 04, 03:21 PM
Jay Honeck
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Surely different pattern *speeds* in different conditions, does not imply
different *patterns*, does it?


Personally, I like to make a "figure-8" on downwind, just to break the
monotony of it all...

;-)

Of course I fly the same pattern each time. We're talking approach speeds
here.

Quite frankly, most Spam Cans could fly the pattern at full throttle and no
one would care much, other than the noise Nazis on the ground. My maximum
forward speed is only about 10 knots over what King Airs *normally* fly
their approaches at...

There are two reasons we don't:

1. Because every other Spam Can in the pattern is usually doing 80 - 90.
2. Because inexperienced pilots have a terrible time landing if they don't
fly a traditional stabilized approach.

These are very good reasons, indeed, and I'm not arguing otherwise -- but to
say you must (or should) ALWAYS fly the pattern at 80 is a bit too stiff.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"


  #55  
Old November 24th 04, 05:42 PM
Peter Duniho
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"Mike Rapoport" wrote in message
nk.net...
Why would anyone want to fly around the pattern at a constant altitude
with gear and flaps out except on a circling approach? I was leave the
gear and flaps up until I want to descend. I was under the impression
that virtually everyone did it this way.


Your impression is mistaken. In fact, I've never had a single instructor
comment on my habit of lowering the gear as I enter the downwind, and I see
plenty of retractable gear airplanes flying in the pattern with their gear
lowered.

Just as a "for example", in my airplane having the flaps and gear out do a
couple of things: they help stablize the aircraft, making flying in the
pattern easier, and the flaps ensure that even though I'm slowing to 80
knots in the pattern, I'm still comfortably above stall speed. Aircraft
handling is significantly better with the flaps and gear out.

When I was flying 182RGs, I found similar benefits, though the stabilizing
factor was the primary issue (stall speed wasn't as big of a problem, being
lower than in the airplane I fly now).

But, even if you prefer to fly with gear and flaps up until beginning your
descent, you still need less power during the descent than you needed during
level flight in the pattern. It doesn't change the fundamentals of what I
wrote.

Pete


  #56  
Old November 24th 04, 06:11 PM
Ditch
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Dang -- and here I was all set to fly to California for my biennial...


Come on out...I'll do your Flight Review for ya. I can even show you a Caravan
painted in Fed Ex colors....like that's exciting.




-John
*You are nothing until you have flown a Douglas, Lockheed, Grumman or North
American*
  #57  
Old November 24th 04, 07:07 PM
Mike Rapoport
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"Peter Duniho" wrote in message
...
"Mike Rapoport" wrote in message
nk.net...
Why would anyone want to fly around the pattern at a constant altitude
with gear and flaps out except on a circling approach? I was leave the
gear and flaps up until I want to descend. I was under the impression
that virtually everyone did it this way.


Your impression is mistaken. In fact, I've never had a single instructor
comment on my habit of lowering the gear as I enter the downwind, and I
see plenty of retractable gear airplanes flying in the pattern with their
gear lowered.

Just as a "for example", in my airplane having the flaps and gear out do a
couple of things: they help stablize the aircraft, making flying in the
pattern easier, and the flaps ensure that even though I'm slowing to 80
knots in the pattern, I'm still comfortably above stall speed. Aircraft
handling is significantly better with the flaps and gear out.

When I was flying 182RGs, I found similar benefits, though the stabilizing
factor was the primary issue (stall speed wasn't as big of a problem,
being lower than in the airplane I fly now).

But, even if you prefer to fly with gear and flaps up until beginning your
descent, you still need less power during the descent than you needed
during level flight in the pattern. It doesn't change the fundamentals of
what I wrote.

Pete


Interesting

In the MU-2, I always lower the gear and 5deg flaps on downwind between
midfield and abeam the numbers depending on how much speed I need to lose..
I go to 20deg flaps on base and do nothing on final. Power is only changed
if I misjudged something. On an ILS it is the same drill without the turns,
flaps 5deg with gear up until one dot high then gear down, at 1/2 dot high
flaps 20deg. Again power isn't changed until landing unless there is a
large wind change between GS intercept and the runway.

It has been a few years but I remember my Turbo Lance being the same with
16.5"MP being the required power setting.

The Helio is different. The trick is to slow down as soon as possible
because the flap speed is only 70kts. Once full flaps are set then slow
down and ADD power to slow down some more. The better you get the more
lower the speed and more power will be required. The limit is about 30kts
and full power. I can't do that yet but I saw it demonstrated at OSH this
year.

Mike
MU-2


Mike
MU-2


  #58  
Old November 24th 04, 09:25 PM
Peter Duniho
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"Mike Rapoport" wrote in message
ink.net...
In the MU-2, I always lower the gear and 5deg flaps on downwind between
midfield and abeam the numbers depending on how much speed I need to
lose.. I go to 20deg flaps on base and do nothing on final. Power is only
changed if I misjudged something. On an ILS it is the same drill without
the turns, flaps 5deg with gear up until one dot high then gear down, at
1/2 dot high flaps 20deg. Again power isn't changed until landing unless
there is a large wind change between GS intercept and the runway.

It has been a few years but I remember my Turbo Lance being the same with
16.5"MP being the required power setting.


I'm a bit amazed that you descended to the runway in your Turbo Lance with a
power setting of 16.5" MP (regardless of what RPM you also use/see at that
setting...it does matter though). I have a very draggy airplane (Lake
Renegade) even without the gear and flaps out, but my descent power setting
is generally in the 13-15" range, depending on weight, wind, etc. Never
having flown a Lance (turbo or otherwise), I don't know first-hand, but I'd
expect a descending pattern flown at 16.5" MP to be pretty wide.

As far as comparison with the MU-2 goes, I'm not convinced it's necessarily
a great comparison. If I recall, the MU-2 has relatively high wing loading,
which should make descents easier. Also, in a twin (a turbine no less) I
would certainly expect a wider pattern to be appropriate. That's ignoring
whether the differences between turbines and pistons, including prop
systems, have any effect (I'm not sure they do, but I'm not sure they don't
either).

In my single-engine piston airplane, I try to stay reasonably close to the
runway, probably not a priority for you in your turbine twin. Some people
even go so far as to fly power-off descents in the pattern. In that extreme
example, obviously descent power is less than level-flight power.

The Helio is different. The trick is to slow down as soon as possible
because the flap speed is only 70kts. Once full flaps are set then slow
down and ADD power to slow down some more. The better you get the more
lower the speed and more power will be required. The limit is about 30kts
and full power. I can't do that yet but I saw it demonstrated at OSH this
year.


Well, I suppose if you really want to practice the short-field stuff (and
with a Helio, why wouldn't you?) flying power-on "backside of the power
curve", that's fine. But it's hardly applicable to this discussion. All
airplanes can land much shorter with appropriate power-on, slow-flight
techniques, but we normally avoid that part of the flight envelope.

I certainly concede that in any airplane, if you want to steepen your
descent without reducing power, you can simply fly at an appropriate
airspeed slower than max L/D speed (to a point, of course). But that's not
a normal operation, and I don't think it applies here.

Pete


  #59  
Old November 24th 04, 09:25 PM
Jay Honeck
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Default

Come on out...I'll do your Flight Review for ya. I can even show you a
Caravan
painted in Fed Ex colors....like that's exciting.


If we get to actually *fly* it, you've got a deal!

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


  #60  
Old November 24th 04, 10:21 PM
Andrew Gideon
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One interesting side-effect of this thread:

It reminded me to remind the plane captain for our 182RG to have the gear
horn set to a slightly lower MP. It currently hoots intermittently at
about 15"...which is where the power needs to be to do about 80 or so
clean.

- Andrew

 




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