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01-02-2011, 06:47 PM
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Join Date: Sep 2006
Location: Defiance, MO
Posts: 1,674
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Do you do partial power take-offs?
I was always taught to use full power until you get to a safe altitude (typically pattern altitude). When I started to fly my RV-6A four years ago I wondered whether I really needed full power on every take-off, after all I am in the air in 500 ft, but I still use full power. Now in the cold of STL this winter I have been again thinking if I ought to use less then full power as the plane is even more peppy. Just wondering how many people use less then full throttle for take-off.
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Philip
RV-6A - 14+ years, 950+ hours
Based at 1H0 (Creve Coeur)
Paid dues yearly since 2007
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01-02-2011, 07:02 PM
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Join Date: Mar 2009
Location: NE Where
Posts: 339
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Why are you considering reduced power take-offs? Are you running an engine with full power time limits? Do you perceive a benefit from reduced power take-offs? Once we know your goals then we can better address your question.
George
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01-02-2011, 07:02 PM
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Join Date: Sep 2006
Location: Townsend, Montana
Posts: 3,179
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I use full power always.
disclaimer: I've only got 7.2hrs on her and I'm breaking in my engine.
Soon I will be using full power until I reach 1000' then pull back to 2500.
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Retired Dam guy. Life is good.
Brian, N155BKsold but bought back.
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01-02-2011, 07:34 PM
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Join Date: Mar 2008
Location: Salem, Va.
Posts: 50
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Full power take
The only time I don't is when I am in a formation take off. I use full power even time with a 6000ft runway just because it is more fun and impresses the locals 
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Jeff and Linda Stubbs
Roanoke, Va.
EAA chapter 646 President
Van's RV-7A
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01-02-2011, 07:35 PM
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Join Date: Feb 2005
Location: Huskerland, USA
Posts: 5,862
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I rarely use full power. Waste of fuel.
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RV-7 : In the hangar
RV-10 : In the hangar
RV-12 : Built and sold
RV-44 : 4 place helicopter on order.
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01-02-2011, 07:49 PM
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Join Date: Oct 2010
Location: Lancaster, PA
Posts: 144
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Always full power unless practicing high density altitude takeoffs. But then again that's in a Piper Archer and not the RV-7 I'm working on :-(
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Andrew
Lancaster, PA l RV-7 #3898 l Empennage l N627AB
"I fly because it releases my mind from the tyranny of petty things" ~Antoine de Saint-Exupery
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01-02-2011, 07:56 PM
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Join Date: Jul 2010
Location: Hendersonville, NC
Posts: 167
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Quote:
Originally Posted by plehrke
I was always taught to use full power until you get to a safe altitude (typically pattern altitude). When I started to fly my RV-6A four years ago I wondered whether I really needed full power on every take-off, after all I am in the air in 500 ft, but I still use full power. Now in the cold of STL this winter I have been again thinking if I ought to use less then full power as the plane is even more peppy. Just wondering how many people use less then full throttle for take-off.
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Altitude is my friend :-). Yes, full power, full rpm till 1000', then 2500rpm WOT till cruising altitude. IMHO it's safer to get up quicker, and it's certainly more fun! :-)))))).
__________________
Steve Jarrell
Building RV-14A QB "Freedom"
N614US (June 14 - Flag Day)
Dues Paid - Gladly!
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01-02-2011, 08:02 PM
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Join Date: Nov 2005
Location: KRTS
Posts: 1,798
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As the old adage goes, the most worthless things to a pilot are runway behind you, altitude above you, and fuel in the truck.
Most airlines use partial power take off's 90% of the time. I'll vary how much power I use for what I fly at work based on conditions.
That said, those are multi engine a/c. If we accept that we're in a single engine a/c and remove engine out considerations, then yes for longevity you can probably lengthen the life if your engine by minimizing your use of full throttle. However if you're doing a reduced power takeoff, and cruise climb to cruise alt you're almost guaranteed to burn more gas than to use full power to altitude, where you can get back to a cruise power setting, speed and fuel burn sooner. Try testing it out some time. Do a reduced power take off and cruise climb to say 10K', and see how long it takes and how much fuel you burn. Then do it again with full power and a Vy climb to 10K. Curious to see the results if anyone tries it out.
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Next?, TBD
IAR-823, SOLD
RV-8, SOLD
RV-7, SOLD
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01-02-2011, 08:04 PM
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Join Date: Sep 2006
Location: Defiance, MO
Posts: 1,674
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Quote:
Originally Posted by sjarrell
Altitude is my friend :-). Yes, full power, full rpm till 1000', then 2500rpm WOT till cruising altitude. IMHO it's safer to get up quicker, and it's certainly more fun! :-)))))).
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I agree with the more fun and get to safe altitude faster. Of coarse everybodies situation is different (short field etc) but I fly out of an airport that is under the 1700 ft level of a Class B. Therefore I can only climb 1000 ft and then have to level off and fly 5-10 nm before I can start a slow climb until clear of the Class B.
__________________
Philip
RV-6A - 14+ years, 950+ hours
Based at 1H0 (Creve Coeur)
Paid dues yearly since 2007
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01-02-2011, 11:46 PM
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Join Date: Oct 2006
Location: Seattle, wa
Posts: 679
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On many piston aircraft a slightly reduced power takeoff is potentially harmful because you do not engage the full power enriching that provides extra cooling fuel on the slow, high power pull on takeoff. A fully loaded pig 172 at sea level on a hot day, fixed pitch, way over square limping into the air with little cooling air and a throttle pulled back 1/4" with CHTs climbing through 400f is a perfect example of why it is often taught not to do partial power takeoffs in a piston acft........
...... However, this is NOT the senario with most RVs; Most are so nimble they can takeoff with a very significant power reduction and not create CHT cooling issues as described above. Is this easier on the engine? Yes. Will the engine last longer? Perhaps not. Most RVs might rust out before they wear out. Will this save gas? Depends. One thing I have noticed using a lot of all around reduced power ops is the oil gets dark faster. I'm not sure but perhaps extensive use of reduced power (all around) is making the oil get darker faster because the rings are allowing more blow by with less pressure? Any gurus on this one?
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