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How to fly Constant Speed?

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bobrundle2(at)hotmail.com
Guest

Posted: Mon Jul 10, 2006 8:58 pm Post subject: How to fly Constant Speed?

Can someone explain how to fly a constant speed prop?  I can't seem to find 

much info in the wealth of flying books I have here.  Any recommended books?



So far I've read:

  To reduce power: Set throttle to desired RPM.  See prop to MP, RPM will 

remain constant.

  To increase power: Set prop to fine.  Increase throttle/RPM.



Correct? Else?



BobR



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rv8ch

Joined: 10 Jan 2006
Posts: 250
Location: Switzerland

Posted: Tue Jul 11, 2006 12:26 am Post subject: How to fly Constant Speed?

bob rundle wrote:

 	  Quote: 	
		   Can someone explain how to fly a constant speed prop?  I can't seem to 

 find much info in the wealth of flying books I have here.  Any 

 recommended books?


	


It's not hard, but I think the best would be to spend some

time with an instructor.  Perhaps 30 minutes of "ground school"

to explain the techniques, followed by a little bit of time in

the air.  You might combine this with a BFR, and kill two birds

with one stone.



-- 

Mickey Coggins

http://www.rv8.ch/

#82007 finishing

do not archive

_________________
Mickey Coggins
http://www.rv8.ch/

Gary.A.Sobek

Joined: 09 Jan 2006
Posts: 217
Location: SoCAL USA

Posted: Tue Jul 11, 2006 4:00 am Post subject: How to fly Constant Speed?

Here is what Lycoming has to say:

http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/basicPowerSequence.html



http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/powerSettings.html



http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/lowPowerLowRPM.html



http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/oldWivesTales.html



Gary A. Sobek

"My Sanity" RV-6 N157GS O-320 Hartzell,

1,892 + Flying Hours So. CA, USA

http://SoCAL_WVAF.rvproject.com



----Original Message Follows----

Reply-To: rv-list(at)matronics.com






Can someone explain how to fly a constant speed prop?  I can't seem to find 

much info in the wealth of flying books I have here.  Any recommended books?



So far I've read:

  To reduce power: Set throttle to desired RPM.  See prop to MP, RPM will 

remain constant.

  To increase power: Set prop to fine.  Increase throttle/RPM.



Correct? Else?



BobR



_________________________________________________________________

Don’t just search. Find. Check out the new MSN Search! 

http://search.msn.click-url.com/go/onm00200636ave/direct/01/





http://www.matronics.com/Navigator?RV-List

http://wiki.matronics.com

pbesing(at)yahoo.com
Guest

Posted: Tue Jul 11, 2006 6:26 am Post subject: How to fly Constant Speed?

Yes definately get some instruction.  You'll learn

procedures and techniques with landing, etc that

you'll want to experience before you fly with a CS

prop.  Not a big science, but as mentioned already, a

flight with a CFI on using a CS prop would be very

beneficial.



Paul Besing

--- bob rundle <bobrundle2(at)hotmail.com> wrote:



 	  Quote: 	
		   

 <bobrundle2(at)hotmail.com>

 

 Can someone explain how to fly a constant speed

 prop?  I can't seem to find 

 much info in the wealth of flying books I have here.

  Any recommended books?

 

 So far I've read:

   To reduce power: Set throttle to desired RPM.  See

 prop to MP, RPM will 

 remain constant.

   To increase power: Set prop to fine.  Increase

 throttle/RPM.

 

 Correct? Else?

 

 BobR

 



_________________________________________________________________
	


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 Search! 



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 	  Quote: 	
		   

 

 

 



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__________________________________________________

dbris200(at)sbcglobal.net
Guest

Posted: Tue Jul 11, 2006 7:23 am Post subject: How to fly Constant Speed?

It's interesting to note that Lycoming (in the second link) says that running oversquare is no problem but in the first link they say:

 <>TO INCREASE POWER - first, enrich mixture, increase RPM, then follow with throttle.</>

 <>TO DECREASE POWER - first, reduce throttle, reduce RPM, and then adjust mixture. </>

 <>

 Be nice if they got their stories straight.</> 

 

 Dave

 <></><>

 do not archive

 </>

 RV6 Flyer wrote:

  	  Quote: 	
		  --> RV-List message posted by: "RV6 Flyer" <rv6_flyer(at)hotmail.com> (rv6_flyer(at)hotmail.com)   

   

   

 Here is what Lycoming has to say:   

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/basicPowerSequence.html   

   

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/powerSettings.html   

   

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/lowPowerLowRPM.html   

   

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/oldWivesTales.html   

   

   

   

 Gary A. Sobek   

 "My Sanity" RV-6 N157GS O-320 Hartzell,   

 1,892 + Flying Hours So. CA, USA   

 http://SoCAL_WVAF.rvproject.com   

   

   

   

 ----Original Message Follows----   

 Reply-To: rv-list(at)matronics.com (rv-list(at)matronics.com)   

   

 --> RV-List message posted by: "bob rundle" <bobrundle2(at)hotmail.com> (bobrundle2(at)hotmail.com)   

   

 Can someone explain how to fly a constant speed prop?  I can't seem to find much info in the wealth of flying books I have here.  Any recommended books?   

   

 So far I've read:   

  To reduce power: Set throttle to desired RPM.  See prop to MP, RPM will remain constant.   

  To increase power: Set prop to fine.  Increase throttle/RPM.   

   

 Correct? Else?   

   

 BobR   

   

 _________________________________________________________________   

 Don’t just search. Find. Check out the new MSN Search! http://search.msn.click-url.com/go/onm00200636ave/direct/01/   

   

   

   

   

 http://www.matronics.com/Navigator?RV-List   

 http://wiki.matronics.com   

   

   

   

   

   

   

   

   

   

   

   

 http://www.matronics.com/Navigator?RV-List   

   

   

   

 http://wiki.matronics.com

Ollie Washburn

Joined: 10 Jan 2006
Posts: 56
Location: Central Florida

Posted: Tue Jul 11, 2006 9:44 am Post subject: How to fly Constant Speed?

There story is straight. Oversquare is OK, but when you increase power they don't want you to be running along at say 2100 rpm and then advance the throttle to full power.

  

 



 Ollie

 [quote] ---

_________________
Ollie RV6-A & Rans S7S
Central FL

lsbrv7a(at)yahoo.com
Guest

Posted: Tue Jul 11, 2006 10:04 am Post subject: How to fly Constant Speed?

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> I read Flying High Performance Singles and Twins and Flying the Beech Bonanzas.  They provide examples of power settings and the resulting performance of the aircraft.  As an example, from study level flight reducing the MP by 5 inches will cause the Bonanza to descend at 500 fpm.  So will extending the landing gear.

   

  My Basic rules

   

  1 More MP (Manifold Pressure) means more power

  2 Closing throttle and climbing will decrease MP

  3 MP will not exceed density altitude pressure  without assistance, will equal it with engine off, and can be a predictor of takeoff performance.

  4 More RPM means more power, and use maximum for takeoff.

  5 High power and low RPM is bad.  Causes unnecessary engine stress.

  6 High RPM means high noise and engine wear.

  7 Low power and high RPM can act as an aerodynamic  brake on descent or approach.

bob rundle <bobrundle2(at)hotmail.com> wrote:   	  Quote: 	
		  --> RV-List message posted by: "bob rundle" 



Can someone explain how to fly a constant speed prop? I can't seem to find 

much info in the wealth of flying books I have here. Any recommended books?



	


Sherman Butler

RV-7a Wings

Idaho Falls

khorton01(at)rogers.com
Guest

Posted: Tue Jul 11, 2006 1:32 pm Post subject: How to fly Constant Speed?

It all depends on the exact engine model.  If you look at the power charts in the Lycoming Operator's Manual, some power charts show a dashed line which is the maximum allowable manifold pressure for continuous operations at a given RPM (e.g. O-360-A, IO-360-A, and IO-360-B series engines).  Other engines don't have such a limitation.

For the IO-360-A series engines, Lycoming allows full throttle at 2400 rpm or higher.  At 2300 rpm they recommend a max MP of 29 inches HG.   The allowable MP drops with rpm to 25 " HG at 1800 rpm.  So, oversquare operation is OK, within limits.  So it still makes sense to increase the rpm before increasing the MP, and to reduce the MP before reducing the rpm.



Kevin Horton



On 11 Jul 2006, at 11:22, D.Bristol wrote:

 	  Quote: 	
		    It's interesting to note that Lycoming (in the second link) says that running oversquare is no problem but in the first link they say:

 <>TO INCREASE POWER - first, enrich mixture, increase RPM, then follow with throttle.

 <>TO DECREASE POWER - first, reduce throttle, reduce RPM, and then adjust mixture. 

 <>

 Be nice if they got their stories straight. 

 

 Dave

 <><>

 do not archive

 

 RV6 Flyer wrote:

  	  Quote: 	
		  --> RV-List message posted by: "RV6 Flyer" <rv6_flyer(at)hotmail.com> (rv6_flyer(at)hotmail.com)  

  

  

 Here is what Lycoming has to say:  

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/basicPowerSequence.html  

  

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/powerSettings.html  

  

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/lowPowerLowRPM.html  

  

 http://www.lycoming.textron.com/main.jsp?bodyPage=/support/publications/keyReprints/operation/oldWivesTales.html  

  

  

  

 Gary A. Sobek  

 "My Sanity" RV-6 N157GS O-320 Hartzell,  

 1,892 + Flying Hours So. CA, USA  

 http://SoCAL_WVAF.rvproject.com  

  

  

  

 ----Original Message Follows----  

 Reply-To: rv-list(at)matronics.com (rv-list(at)matronics.com)  

  

 --> RV-List message posted by: "bob rundle" <bobrundle2(at)hotmail.com> (bobrundle2(at)hotmail.com)  

  

 Can someone explain how to fly a constant speed prop?  I can't seem to find much info in the wealth of flying books I have here.  Any recommended books?  

  

 So far I've read:  

  To reduce power: Set throttle to desired RPM.  See prop to MP, RPM will remain constant.  

  To increase power: Set prop to fine.  Increase throttle/RPM.  

  

 Correct? Else?

klwerner(at)comcast.net
Guest

Posted: Tue Jul 11, 2006 3:48 pm Post subject: How to fly Constant Speed?

On a sidenote on running  oversquare:  

 How does one with a fixed pitch  propeller operating from low altitude or even sea level deal with said  oversquare scenario's? 

 Isn't that pretty much an oversquare  situation right from the get-go when one applies full take off power?  

 As a Manifold Pressure Gauge is not  required in a fixed pitch airplane, how would one even know  how much oversquare they are during the takeoff roll?

  

 Just wondering...

  

 do not archive

 [quote]   ---

ebundy(at)speedyquick.net
Guest

Posted: Tue Jul 11, 2006 4:58 pm Post subject: How to fly Constant Speed?

Oversquare operation has been pretty much de-bunked as  an old wives tale.  Most POH's show available operations well into  oversquare territory.  My fixed-pitch prop RV operates oversquare on pretty  much every takeoff.  I have MAP in mine and at sea level I show  31" at 2200 rpm on takeoff.  I usually pull back to 25" on climb (RPM  approx 2300) and keep bumping the power back up to 75% as I  climb.

  

 If you don't  have MAP, then you don't know you're oversquare and it won't harm the engine.  

  

 Ed  Bundy 



  	  Quote: 	
		     On a sidenote on running    oversquare:  

   How does one with a fixed pitch    propeller operating from low altitude or even sea level deal with said    oversquare scenario's? 

   Isn't that pretty much an    oversquare situation right from the get-go when one applies full take off    power? 

   As a Manifold Pressure Gauge is not    required in a fixed pitch airplane, how would one even    know how much oversquare they are during the takeoff roll?

klwerner(at)comcast.net
Guest

Posted: Tue Jul 11, 2006 5:11 pm Post subject: How to fly Constant Speed?

You get 31"? 

 Ram Air?

  

 What engine & what prop do you  have?

  

 Do not archive

 [quote]   ---

khorton01(at)rogers.com
Guest

Posted: Tue Jul 11, 2006 5:38 pm Post subject: How to fly Constant Speed?

What does your MP read when the engine is stopped on the ground?  31" sounds like a MP gauge that is reading high.

Kevin Horton

do not archive

On 11 Jul 2006, at 20:54, Ed Bundy wrote:

 	  Quote: 	
		   Oversquare operation has been pretty much de-bunked as an old wives tale.  Most POH's show available operations well into oversquare territory.  My fixed-pitch prop RV operates oversquare on pretty much every takeoff.  I have MAP in mine and at sea level I show 31" at 2200 rpm on takeoff.  I usually pull back to 25" on climb (RPM approx 2300) and keep bumping the power back up to 75% as I climb.

  

 If you don't have MAP, then you don't know you're oversquare and it won't harm the engine. 

  

 Ed Bundy 



  	  Quote: 	
		    On a sidenote on running   oversquare:  

  How does one with a fixed pitch   propeller operating from low altitude or even sea level deal with said   oversquare scenario's? 

  Isn't that pretty much an   oversquare situation right from the get-go when one applies full take off   power? 

  As a Manifold Pressure Gauge is not   required in a fixed pitch airplane, how would one even   know how much oversquare they are during the takeoff roll?

garrys(at)tampabay.rr.com
Guest

Posted: Tue Jul 11, 2006 5:47 pm Post subject: How to fly Constant Speed?

Amen!  I always thought the most MP you could  get without super/turbo charging was 29.92 inches.  What gives with the 31  inches?

  

 Garry Stout

 RV7A in progress

 [quote]   ---

Tim(at)MyRV10.com
Guest

Posted: Tue Jul 11, 2006 6:42 pm Post subject: How to fly Constant Speed?

Well, the most you could read would be the highest ambient

pressure....and in some areas of the world, it gets into

the 30's....



Or, maybe he got this a long time ago:

"the highest barometric pressure ever recorded in the USA was 31.85 

inches in Northway, Alaska, in January 1989"



Tim Olson - RV-10 N104CD - Flying

do not archive

Garry wrote:

[quote] Amen!  I always thought the most MP you could get without super/turbo 

 charging was 29.92 inches.  What gives with the 31 inches?

  

 Garry Stout

 RV7A in progress

 

     ---

khorton01(at)rogers.com
Guest

Posted: Wed Jul 12, 2006 3:19 am Post subject: How to fly Constant Speed?

"Oversquare" in this context has traditionally meant operation where the MP value in inches of HG exceeds the rpm divided by 100.  I.e. a MP of greater than 24" HG at 2400 rpm.  The Lycoming power charts specifically allow oversquare operation.  E.g., 29" HG MP and 2300 is OK for continuous operations on the IO-360-A.  The whole "avoid oversquare operations" thing is not directly applicable to our engines.  It had it's root in a few old radial engines that didn't like such operations.  Every engine has some limit of MP vs rpm where it won't be happy, but on many engines that limit is not at the magic "oversquare" point.



The info in the Lycoming Operator's Manual doesn't prohibit operation with MP exceeding the values on the power charts.  They just indicate that this is the limit for continuous operations.  Typically, engine manufacturers establish power limits for take-off, with a five minute time limit, and another set of limits for continuous operation.  So Lycoming should have no problem if the MP vs rpm limit for continuous operations is exceeded during take-off.

The rpm during a full throttle climb on a FP aircraft is higher than the rpm during take-off.  I except that the MP vs rpm relationship is quite close to Lycoming's continuous limit for the first part of the climb, but the MP drops as the altitude increases.  So, in practice, very little time is spent with the MP greater than Lycoming's limit for continuous operations.  There are thousands of Lycoming-powered FP RVs flying, and the service history suggests that this is not a problem area.



Typical fixed-pitch type-certificated aircraft have static rpms that are higher than RVs, as they don't need such a coarse pitch prop (their lower cruise speed allows a finer pitch prop).  I expect typical fixed-pitch type-certificated aircraft to have rpm/MP combinations that fall within, or not far outside, Lycoming's limit for continuous operation.



Kevin Horton



On 11 Jul 2006, at 19:43, Konrad L. Werner wrote:

[quote]On a sidenote on running oversquare: 

How does one with a fixed pitch propeller operating from low altitude or even sea level deal with said oversquare scenario's?

Isn't that pretty much an oversquare situation right from the get-go when one applies full take off power?

As a Manifold Pressure Gauge is not required in a fixed pitch airplane, how would one even know how much oversquare they are during the takeoff roll?

 

Just wondering...

 

do not archive

[quote]---

LessDragProd(at)aol.com
Guest

Posted: Wed Jul 12, 2006 12:34 pm Post subject: How to fly Constant Speed?

An interesting discussion.  Strong statements related to the  engine.  And the propeller seems to be ignored.

  

 Certified aircraft have POH power settings directly related to  the engine/propeller combination installed on that aircraft.   Unfortunately, the POH power settings for an RV would be much more  difficult to establish, because of all of the different engine/propeller  combinations used.

  

 Just an aside.  The engine may provide more horsepower with an  increase in RPM, but the propeller requires more horsepower to turn at a given  airspeed with an increase in RPM.

 Empirically, in cruise at full throttle at 7,500', the 72" diameter CS  propeller on a Lycoming O-360 engine requires more horsepower than the  engine produces when the RPM is increased from 2600 to 2700.  This results  in a slight decrease in airspeed.

  

 Regards,

 Jim Ayers

low pass

Joined: 10 Jan 2006
Posts: 32
Location: Houston

Posted: Wed Jul 12, 2006 1:39 pm Post subject: Re: How to fly Constant Speed?

Lots of detail above.  Two VERY GENERAL sequences of operation used to operate a CS prop/engine combo:



Enrich the mixture, increase prop rpm, increase MAP (throttle).  



Decrease MAP (throttle), decrease rpm, lean the mixture.



The specific numbers will vary with engine, prop, AC, etc.  There are also lots of variations to these general sequences.



Search for controllable pitch propeller (FAA lingo).  Try the FAA document, Airplane Flying Handbook.  



http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-5of7.pdf

ebundy(at)speedyquick.net
Guest

Posted: Wed Jul 12, 2006 5:09 pm Post subject: How to fly Constant Speed?

It reads whatever the current pressure setting is.   If it's 30.25, then MP reads 30.25 (at sea level).  During takeoff,  some slight ram pressure develops (my cowl to airbox seal is very tight)  generating maybe 30.50".  I actually meant to say I get 30", but on  occasion when ambient pressure is high, it comes mighty close to  31".

  

 Ed  Bundy 



  	  Quote: 	
		  What does your MP read when the    engine is stopped on the ground? 31" sounds like a MP gauge that is reading    high.   

   Kevin Horton

      do not archive

   

   

      On 11 Jul 2006, at 20:54, Ed Bundy wrote:

    	  Quote: 	
		       Oversquare operation has been pretty      much de-bunked as an old wives tale. Most POH's show available operations      well into oversquare territory. My fixed-pitch prop RV operates oversquare      on pretty much every takeoff. I have MAP in mine and at sea level I show 31"      at 2200 rpm on takeoff. I usually pull back to 25" on climb (RPM approx      2300) and keep bumping the power back up to 75% as I      climb.

     

     If you      don't have MAP, then you don't know you're oversquare and it won't harm the      engine. 

     

     Ed      Bundy      



      	  Quote: 	
		         On a sidenote on running        oversquare: 

       How does one with a fixed pitch        propeller operating from low altitude or even sea level deal with said        oversquare scenario's? 

       Isn't that pretty much an        oversquare situation right from the get-go when one applies full take off        power? 

       As a Manifold Pressure Gauge is        not required in a fixed pitch airplane, how would one even know how much        oversquare they are during the takeoff roll?

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