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01-15-2009, 11:10 AM
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Join Date: Jul 2007
Location: Rock Hill, SC
Posts: 390
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Does CS prop help in IMC?
I've got a decent amount of hours in IMC behind a FP propeller. At times it results in a lot of throttle jockeying in heavy updrafts and downdrafts.
I have only flown with a CS prop in VMC on basically calm days. Those of you who have flown behind a CS prop in IMC, do you find it makes engine management easier? Can you just "set and forget" the RPM?
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Jonathan Hines
Charlotte, NC
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01-15-2009, 11:16 AM
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Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,398
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Quote:
Originally Posted by JHines
I've got a decent amount of hours in IMC behind a FP propeller. At times it results in a lot of throttle jockeying in heavy updrafts and downdrafts.
I have only flown with a CS prop in VMC on basically calm days. Those of you who have flown behind a CS prop in IMC, do you find it makes engine management easier? Can you just "set and forget" the RPM?
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I suppose. But its not really a set and forget, in fact its one more thing to deal with. I could make the argument that a c/s prop under a high workload enviornment like IMC adds to the list of things to deal with. I certianly would not have listed "management in IMC" in the top ten reasons to own a C/S prop. Nor would it be in the top 50 items on my mind for things to deal with IMC. I dont consider it a factor one way or the other.
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01-15-2009, 11:25 AM
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VAF Moderator / Line Boy
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Join Date: Jan 2005
Location: Dayton, NV
Posts: 12,245
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I agree with Mike - management of RPM wouldn't be anywhere near the top of my list of things to manage in IMC. In fact, after initial climb, I usually set the RPM I like, and don't touch it again until short final.
But then, flying a fixed pitch prop in IMC, I set up cruise power and then don't touch the throttle either - I fly pitch (or let the autopilot do it). Never really thought about playing with the throttle, unless I am managing a descent.
Paul
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Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
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01-15-2009, 12:30 PM
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Join Date: Jul 2007
Location: Rock Hill, SC
Posts: 390
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Quote:
Originally Posted by Ironflight
I agree with Mike - management of RPM wouldn't be anywhere near the top of my list of things to manage in IMC. In fact, after initial climb, I usually set the RPM I like, and don't touch it again until short final.
<SNIP>
Paul
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Hi Paul,
I know in extreme situations one should just fly attitude, keep under Va and tell ATC "unable" on the assigned altitude.
I am thinking more of situations such as maintaining altitude +/- 100 feet while transiting 300 to 500 FPM updrafts/downdrafts.
Maybe I'm using some poor piloting techinques, but I've found that in a Skyhawk or similar in such conditions, I would need to pull the throttle to avoid an overspeed or firewall it to maintain altitude.
Quote:
Originally Posted by Ironflight
But then, flying a fixed pitch prop in IMC, I set up cruise power and then don't touch the throttle either - I fly pitch (or let the autopilot do it). Never really thought about playing with the throttle, unless I am managing a descent.
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this is what I do in normal conditions.
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Jonathan Hines
Charlotte, NC
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01-15-2009, 12:59 PM
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Join Date: Jun 2006
Location: Cincinnati, OH
Posts: 837
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I would have to disagree with the folks who say it's a hindrance. Having the prop governor control your RPM to prevent overspeeding while fighting up/downdrafts doesn't seem like it would be a problem to me. It's almost like saying that managing an autopilot in IMC is just another thing to increase your workload. Simply not the case! Another possible side benefit of C/S is the ability to shed some prop ice by manipulating the blade pitch.
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Ron Leach
RV-7 N713CM reserved VAF # 603
Cincinnati
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"Wish I didn't know now what I didn't know then".
.....Bob Seger
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01-15-2009, 01:05 PM
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Join Date: Dec 2004
Location: Gold Hill, NC25
Posts: 2,398
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Quote:
Originally Posted by captainron
I would have to disagree with the folks who say it's a hindrance. Having the prop governor control your RPM to prevent overspeeding while fighting up/downdrafts doesn't seem like it would be a problem to me. It's almost like saying that managing an autopilot in IMC is just another thing to increase your workload. Simply not the case! Another possible side benefit of C/S is the ability to shed some prop ice by manipulating the blade pitch.
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Good points Ron. I had not considered the blue lever de-ice function before. Thats a good one.
I personally have zero fixed pitch RV IMC time for any comparison.
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01-15-2009, 05:35 PM
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Join Date: Jan 2005
Location: Ottawa, Canada
Posts: 2,357
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Another plus for the CS prop in IMC is that if you screw up and end up in icing conditions, you will have better climb performance to get out of the stuff.
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01-15-2009, 05:42 PM
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Join Date: Jan 2006
Location: Green Bay, WI (GRB)
Posts: 476
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Another advantage for the CS the ability to keep your speed up on the approach and still be in a good position to slow down and land. This worked well for me when on the ILS with jet traffic in trail.
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Don Pansier
Green Bay, WI (GRB)
RV-7 N450DP
W9LYX
Antennas for Experimental Aircraft
www.deltapopaviation.com
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02-13-2009, 10:00 PM
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Join Date: Aug 2005
Location: Pasadena CA
Posts: 2,484
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CS prop is less workload in the air... no matter, VFR or IFR.
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Stephen Samuelian, CFII, A&P IA, CTO
RV4 wing in Jig @ KPOC
RV7 emp built
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02-13-2009, 10:10 PM
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fugio ergo sum
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Join Date: Apr 2006
Location: Carlsbad, NM
Posts: 1,912
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Quote:
Originally Posted by osxuser
CS prop is less workload in the air... no matter, VFR or IFR.
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I agree with that but there are times when you have to pull and push that throttle (or prop control) with either prop type. Today there was pretty strong mountain wave activity along my route and I had to pull the throttle back on my fixed pitch equipped airplane to keep the indicated airspeed to something reasonable in the ups. I would have had to do just the same with a constant speed.
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Larry Pardue
Carlsbad, NM
RV-6 N441LP Flying
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