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TAS at Alt for Yak52 flight planning

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Mark Scrivener

Joined: 04 Aug 2007
Posts: 10
Location: San Jose, CA

Posted: Tue Oct 02, 2007 7:51 pm Post subject: TAS at Alt for Yak52 flight planning

I'm taking the '52 cross country this week and was wondering what a good TAS is for planning purposes. Assuming I pull the power back to 68%/5 or something similar, what should I plan on for true airspeed at an ALT of 7,000 to 9,000?



Also, what is typically the most efficient cruising altitude for the 52? Obviously there is less drag up higher, but you burn more fuel getting up there.



Thanks!

Mark

craig(at)ustek.com
Guest

Posted: Wed Oct 03, 2007 2:46 am Post subject: TAS at Alt for Yak52 flight planning

Mark,

  

 When flying cross country in my YAK-52W, I typically fly 70% which is 2050rpm and 29"mp.  This yeilds a pretty constant 120-130kts TAS with a fuel flow of 16-18gph at 5-8K feet.  ( I have a EI fuel flow wired to a Garmin 430)

  

 Reducing power to 60%, 1820rpm, 27"mp, same altitudes, I get 110-115kts TAS with a fuel flow of 12-14gph.

  

 Hope that helps!

  

 Craig

 N90GC



 

  From: Mark Scrivener

Sent: Tue 10/2/2007 11:51 PM

To: yak-list(at)matronics.com

Subject: TAS at Alt for Yak52 flight planning

 [quote]--> Yak-List message posted by: "Mark Scrivener" <mark_scrivener(at)yahoo.com>



I'm taking the '52 cross country this week and was wondering what a good TAS is for planning purposes. Assuming I pull the power back to 68%/5 or something similar, what should I plan on for true airspeed at an ALT of 7,000 to 9,000?



Also, what is typically the most efficient cruising altitude for the 52? Obviously there is less drag up higher, but you burn more fuel getting up there.



Thanks!

Mark





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=137767#137767





[b]

Mark Scrivener

Joined: 04 Aug 2007
Posts: 10
Location: San Jose, CA

Posted: Wed Oct 03, 2007 8:51 am Post subject: Re: TAS at Alt for Yak52 flight planning

Thanks Craig.



I guess I was a little optimistic - thinking I would get 130kts TAS and 13gph up at ~9k ft. 



No fuel flow meter in my 52, just the stock Russian stuff and a hand held GPS. Quite different from my usual cross country ride with multiple moving maps and at least 2 readouts for everything. Should be fun...



-Mark

brian-1927(at)lloyd.com
Guest

Posted: Wed Oct 03, 2007 9:50 am Post subject: TAS at Alt for Yak52 flight planning

On Oct 3, 2007, at 3:45 AM, Craig Schneider wrote:



 	  Quote: 	
		   Mark,



 When flying cross country in my YAK-52W, I typically fly 70% which  

 is 2050rpm and 29"mp.  This yeilds a pretty constant 120-130kts TAS  

 with a fuel flow of 16-18gph at 5-8K feet.  ( I have a EI fuel flow  

 wired to a Garmin 430)



 Reducing power to 60%, 1820rpm, 27"mp, same altitudes, I get  

 110-115kts TAS with a fuel flow of 12-14gph.


	


Generally speaking, higher is going to be better. I found the most  

efficient altitude for the CJ6A to be 11,000'-12,000'. I would pull  

the RPM back to 1850 and use full throttle. Fuel burn was around  

11gph with a TAS of about 125kts. I could comfortably fly 3 hour legs  

with reserve that way. With tailwinds I have flown a 450nm leg before.



If you are looking for efficiency plan on operating with the throttle  

wide open and only make power changes with the prop control (RPM).  

The Yak-52, being overpowered, is going to have its most efficient  

altitude up higher. Basically you want to climb until your IAS in  

cruise is best L/D. That is pretty high. But in order to get best  

efficiency you need to stay up there as long as possible in order to  

offset the cost of getting up there.



But given the available climb from the Yak-52, I would certainly be  

looking to cruise up above 12,000'.

--

Brian Lloyd                         3191 Western Drive

brian HYPHEN 1927 AT lloyd DOT com    Cameron Park, CA 95682

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C

Dale

Joined: 30 May 2007
Posts: 178

Posted: Wed Oct 03, 2007 1:41 pm Post subject: Re: TAS at Alt for Yak52 flight planning

A friend of mine cautioned me not to run a 9cyl below 2000 RPM at cruise because of the vibration resonance found in radial engines is transmitted through the airframe at that RPM or lower. I can't remember the airline that changed hands and thought they could save money and extend range with lower RPM's.  The airline found out the tails were suffering cracks and needed repaired. When they returned to the 2000 RPM min the crack problem once again disappeared. My friend was maintaince chief for a fleet of radial powered cargo transports flying in the Caribbean islands for years. I trust him and do not operate below 70% for this reason and feel safe than sorry is in order for me, everyone else can do what they want as I am in no way a expert and am only expressing my opinion.

cjpilot710(at)aol.com
Guest

Posted: Wed Oct 03, 2007 2:52 pm Post subject: TAS at Alt for Yak52 flight planning

In a message dated 10/3/2007 5:47:50 P.M. Eastern Daylight Time,  hdinamic(at)qwest.net writes:

  

 That may have been for a particular aircraft/engine combination.  It's  not a general rule.  We cruise our B-17G at 1800 rpm all the time, there is  not 'resonance vibration' (unless the props are out of syncopation).  Was  that airline "Macky"?  If so, they operated out of Miami, Fl. for  years.  They had mixed fleet of DC-4, DC-3, and C-46s.  I've never  heard of any of these aircraft having that problem.  That airline was quite  a "colorful" bunch.  Gipsies, nar-do-wells, laid off airlines pilots, or  just plain old-fart pilots, run by a real character.  I try once to get a  job there.  Took one look at me and said (honest to God) "Go away  kid".

  

 I do believe that Lindbergh taught this during WW2 so as to  extend the range of military aircraft.  I never heard of a resonance  vibration indicative to round engines, though.  It is true that the 9 cly  Wright 1820 is not as smooth running at the 14 cly P&W-1830 but I never  heard of vibration problems in either engine.

  

 Jim "Pappy" Goolsby

  

  	  Quote: 	
		  -->    Yak-List message posted by: "Dale" <hdinamic(at)qwest.net>



A friend    of mine cautioned me not to run a 9cyl below 2000 RPM at cruise because of the    vibration resonance found in radial engines is transmitted through the    airframe at that RPM or lower. I can't remember the airline that changed hands    and thought they could save money and extend range with lower RPM's.  The    airline found out the tails were suffering cracks and needed repaired. When    they returned to the 2000 RPM min the crack problem once again disappeared. My    friend was maintaince chief for a fleet of radial powered cargo transports    flying in the Caribbean islands for years. I trust him and do not operate    below 70% for this reason and feel safe than sorry is in order for me,    everyone else can do what they want as I am in no way a expert and am only    expressing my opinion. 

	


 

  



See what's new="_blank">Make AOL Your Homepage.

  [quote][b]

dsavarese(at)elmore.rr.co
Guest

Posted: Wed Oct 03, 2007 4:19 pm Post subject: TAS at Alt for Yak52 flight planning

Dale,

Regardless of what you've heard, the M14P is quite comfortable running at

less than 2000 RPM.  If you read the Russian Flight Manual or the M14

Manual, it clearly shows you cruise rpm's at less than 2000 RPM.  It is a

proven fact that this engine is designed to run "over square".  Not by my

say so.  But by the Russian manuals say so.  That means running a higher

manifold pressure (ie: 700 MM) and lower RPM (ie: 64%) is most acceptable

for the M14 mounted on a Yak 52.  Click on this link.  It is right out of

the Russian manual.  http://n9tumimypu.win.aplus.net/Power%20Settings.htm

Dennis

---

viperdoc(at)mindspring.co
Guest

Posted: Wed Oct 03, 2007 6:20 pm Post subject: TAS at Alt for Yak52 flight planning

Mark,

Try setting your throttle and pitch over square. Meaning your manifold

pressure is set higher than your prop. Try 65% at 700 mmHg (70 on the dial).

Nominal one is 65% and 650 mmHg if my memory serves correct (been awhile

since I looked at it for the 52). You will see right at 15 gal/hour fuel

burn or 1 liter/min (standard for the M-14). You will see approximately 130

kts/hr for your airspeed. Plan on 150 mi. legs to be safe. You can push it

to 200nm but. Know it is the proverbial frog bumping its' ass cross country

but you are not going to be a statistic for fuel starvation that way either.

The over square throttle setting is just something a few of the old B17

drivers on the field taught us. You get the best fuel economy and cruise A/S

that way.



--

brian-1927(at)lloyd.com
Guest

Posted: Wed Oct 03, 2007 7:35 pm Post subject: TAS at Alt for Yak52 flight planning

On Oct 3, 2007, at 2:41 PM, Dale wrote:



 	  Quote: 	
		   



 A friend of mine cautioned me not to run a 9cyl below 2000 RPM at  

 cruise because of the vibration resonance found in radial engines  

 is transmitted through the airframe at that RPM or lower. I can't  

 remember the airline that changed hands and thought they could save  

 money and extend range with lower RPM's.


	


Well, my father flew OS2Us, SBDs, SB2Cs, F6Fs, F8Fs, and the SNB in  

the Navy. (He later went on to fly jets but those were the recips he  

flew.) He says that they regularly ran very low RPM, i.e. 1800 or so,  

when flying long legs from the carrier.



 	  Quote: 	
		   The airline found out the tails were suffering cracks and needed  

 repaired. When they returned to the 2000 RPM min the crack problem  

 once again disappeared. My friend was maintaince chief for a fleet  

 of radial powered cargo transports flying in the Caribbean islands  

 for years. I trust him and do not operate below 70% for this reason  

 and feel safe than sorry is in order for me, everyone else can do  

 what they want as I am in no way a expert and am only expressing my  

 opinion.


	


It depends on the aircraft and/or engine.



--

Brian Lloyd                         3191 Western Drive

brian HYPHEN 1927 AT lloyd DOT com    Cameron Park, CA 95682

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

— Antoine de Saint-Exupéry



PGP key ID:          12095C52A32A1B6C

PGP key fingerprint: 3B1D BA11 4913 3254 B6E0  CC09 1209 5C52 A32A 1B6C

Dale

Joined: 30 May 2007
Posts: 178

Posted: Wed Oct 03, 2007 8:41 pm Post subject: Re: TAS at Alt for Yak52 flight planning

Hi Guys



No the airline was a major. I will not argue the point , just telling you what I was told. I am sure you are all correct, just repeating. I remember my friend telling me that it was not  a issue in military aircraft as they were not built to be flown like airliners for hundreds of thousand of hours. Or for that matter just a few thousand and thrown away as the Russians like to do. I have a 1947 V35 that Beech didn't bother to put zinc chromate in either thinking it would be gone in the dust in a few years, and they still haven't figured out why the tails fall off ( read the AD13-2002 ) I get a laugh that the Russians bothered to corrosion treat the 52's considering how long they planned to use them ( I know about the alloy they are built with ). I realize the book numbers from the M-14p power settings also and don't remember my friend saying that the radial or any radial for that matter had a "vibration problem" just that the vibration was transmitted through the airframe and best to avoid it. He did own personally two Beech 18's a DC-3, C-47, DC-4, and a A-26, still has his DC-3. I do listen to him and everyone else for that matter. His experience far exceeds mine.

dabear(at)damned.org
Guest

Posted: Thu Oct 04, 2007 4:07 am Post subject: TAS at Alt for Yak52 flight planning

When flying formation cross country with other Yaks/CJs, I'll regularly 

run at 1860RPM and 580-600MP.  This typically gives me 11Gph fuel burn 

even down around 4-5k alt.



Dabear



Roger Kemp wrote:

[quote] 



 Mark,

 Try setting your throttle and pitch over square. Meaning your manifold

 pressure is set higher than your prop. Try 65% at 700 mmHg (70 on the dial).

 Nominal one is 65% and 650 mmHg if my memory serves correct (been awhile

 since I looked at it for the 52). You will see right at 15 gal/hour fuel

 burn or 1 liter/min (standard for the M-14). You will see approximately 130

 kts/hr for your airspeed. Plan on 150 mi. legs to be safe. You can push it

 to 200nm but. Know it is the proverbial frog bumping its' ass cross country

 but you are not going to be a statistic for fuel starvation that way either.

 The over square throttle setting is just something a few of the old B17

 drivers on the field taught us. You get the best fuel economy and cruise A/S

 that way.



 --

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