X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 20 Dec 2009 19:34:34 -0500 Message-ID: X-Original-Return-Path: Received: from web57503.mail.re1.yahoo.com ([66.196.100.70] verified) by logan.com (CommuniGate Pro SMTP 5.3c4) with SMTP id 4032032 for lml@lancaironline.net; Sun, 20 Dec 2009 10:00:16 -0500 Received-SPF: none receiver=logan.com; client-ip=66.196.100.70; envelope-from=casey.gary@yahoo.com Received: (qmail 68658 invoked by uid 60001); 20 Dec 2009 14:59:41 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=P9CWobj81FaTOGu86rw8K2XX6rlJQuEXFrvh4jTqkVPv5Tj53ax5pdXNDW8zuLbwomaQGLizju0Xe8iwIkLCCUO18pHr639gWh9CwFthjIDtcETWNV4WrV+0ial+ioNAOrvkPabwAM34WPsTGgf5pdpU951t+ELUYB0/376AFZY=; X-Original-Message-ID: <201815.68063.qm@web57503.mail.re1.yahoo.com> X-YMail-OSG: z6kgBT8VM1lrNhgfTbesOTQre4Chsx9mGMPzboyusGh8ZjYijFBy0OOt_4lK4HYJ.jQVOQEND7aU2Im5DkuCNLhk3AzILslvzijLR09wEnz_Y6Ie3Nl2axVNz7soEg_U7gyKm5vLoJ92mC0ybbcPg3E7KX41JyhfpuYeJ19Uoq1fTYUsw4z7J83sZ5218GedlXrNnAiptXY8FN5bftGP_tD0VYN7VpIYKJiP6tb_mIrVTziDfGaPpVOcsgSVNm6wZaCY5Ty9fig7Jm0- Received: from [97.122.191.52] by web57503.mail.re1.yahoo.com via HTTP; Sun, 20 Dec 2009 06:59:40 PST X-Mailer: YahooMailRC/240.3 YahooMailWebService/0.8.100.260964 References: X-Original-Date: Sun, 20 Dec 2009 06:59:40 -0800 (PST) From: Gary Casey Subject: Re: io-550 vs. tsio-550 differences? X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1825597303-1261321180=:68063" --0-1825597303-1261321180=:68063 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable I certainly agree with George in his comments in that a well-designed inter= cooler will offer significant performance benefits at altitudes like 18,000= . When I said "marginal benefit" I was referring to benefit in a more glob= al sense. It all depends on how much of the operation is conducted at 18,0= 00 feet. From my experience I would guess it would be very, very rare for = someone to spend 50% of of the total hours at or near 18,000. A 4-hour fli= ght will spend maybe 30 minutes in climb and 3 minutes in descent from 18,0= 00 for 50% spent at 18,000. A serious cross-country flier might be there f= or, what, 20%? And then how much of that time is spent at 30 inches manifo= ld pressure, burning close to 30 GPH? At lower manifold pressures the high= er inlet temperatures are not as detrimental as they are at full power, whe= re they limit the power output. In other words, 25 inches with a 150F inle= t might be equivalent in power - and nearly equivalent in efficiency - to 24 inches at 100F inlet. Another thing to be aware of - the inlet ai= r temperature does not exactly match the temperature of the inlet charge as= it is trapped in the cylinder, which is, after all, what counts. Tests I = have seen show that the charge is heated about halfway to the cylinder temp= erature. If the cylinder temp is 300F and the incoming charge is 100 the r= esulting charge temperature is about 200. Increase the inlet temp from 100= to 200 and the trapped charge will be at 250, only 50 higher. While no o= ne is truly an average operator, my point was that chasing the optimum perf= ormance at 18,000 feet may not be worth the cost and development expense. = Depends on your goals. All flights involve operation below 10,000 feet whi= le a limited number involve operation above 18,000. When flying my TR182 o= n a lot of cross-countries I flew between 12 and 15 a lot, but flew above 1= 8,000 only a couple of times in 5 years. Like in the drug commercials, these comments are directed only at turbonormalized nonpressu= rized oxygen-equipped aircraft operated in non-commercial environments. Oh= , yeah - and by "average" resource-limited owners :-)=0A=0AI'm not sure I a= gree with George when he says that "Intercoolers have large benefits - - -= even at sea level." In this case the turbo is producing negligible pressu= re, so the temperature rise is dependent only on the heat picked up going t= hrough the turbo and the small compression heating when the turbo has to ov= ercome its own flow restriction. This is also true when cruising at less t= han 10,000 feet at reduced manifold pressure. Is the added weight, cost an= d aerodynamic drag more of a detriment than the cooling is a benefit?=0AGar= y =0A=0A>>Here's another thought: A lot of it might depend on your intende= d usage. If you want to go really high (over 20K) and have maximum perform= ance you might want to consider getting the extra power of the TSIO-550. B= ut if you, like me, might limit altitudes to less than 20K and are more cos= t and fuel economy sensitive, then a lower tech solution might be in order.= I flew for many years behind a Lycoming O-540 that was turbonormalized (C= -TR-182) and it worked quite well. It didn't have an intercooler or automa= tic waste gate - the waste gate was connected to the throttle linkage so th= ere were no extra levers. It was fed by a pressurized carburetor, so that = doesn't apply with a Continental. So the question is, what's wrong with us= ing a standard IO-550 with a turbo and manual waste gate? The Lycomings do= n't bother with a sniffle valve, so there isn't any difference between turb= o, fuel injected, or naturally aspirated engines in that regard. At 18,000 feet the use of an aftercooler has real, but marginal benefit, as the extr= a aerodynamic drag and pressure loss negate most of the charge-cooling bene= fit. Just a thought, suggesting a KISS methodology.=0AGary<<=0A =0A =0AGar= y, =0A =0ASome comments.=0A =0AI think new designed high compression engin= es with compressors of any kind should use our present state of knowledge a= nd incorporate intercoolers - - good intercoolers.=0A =0AThe engine you ar= e discussing had lower compression ratios. As someone else said in this s= ame thread of messages, unless you really know what you are doing, you ca= n screw up and have a very unhappy installation.=0A =0AIntercoolers have la= rge benefits - - - even at sea level. I do not think it is accurate to = claim that intercoolers only have =E2=80=9Cmarginal benefit=E2=80=9D below= 18,000 feet.=0A =0AHere is why I think they are important: At 18,000 fee= t, the compressor discharge temperature on a warm day can easily exceed 20= 0dF. Without an intercooler, 200dF air goes straight to your cylinders= .=0A =0AWith the TN IO-550, the induction air temperature at 30=E2=80= =9D at 18,000 feet on a hot day will be less than 105dF. Typically 95 to = 100. There is a large difference in performance and detonation margins be= tween 200+dF air and < 105dF air. =0A =0AThe O-540 =E2=80=9Csolution=E2= =80=9D does not really provide more fuel economy. Rather, likely just t= he opposite.=0A =0AThe TN IO-550N engine that Tornado Alley delivers to Cir= rus will produce horsepower at 0.38 to 0.39 BHp/lb-fuel/hr across an a= ltitude and power range that spans anywhere from sea level to 29000 feet an= d do so at 200 Hp or at 310 Hp, or anywhere in between. [The real world n= umbers for the Thielert diesel was about 0.36 to 0.37 BHP/lb-fuel/hr.] Ther= e is no other general aviation engine installed in any fleet of aircraft th= at works anywhere near that well across that broad range of operating req= uirements and environment.=0A =0A90% of the hours flown with those engines = are flown between 11,000 and 18,000 feet. =0A =0AThere is a reason why Cir= rus has sold ~ 900+ turbonormalized SR22 aircraft in the last 35 months, i= ncluding 15 months of some of the worst times in general aviation history.= =0A =0AThe reason is - - the systems consistently exceed the expectations = of the owners.=0A =0ADuring that period of time TAT continued to improve a= nd refine those systems. They are, today, about 15 lbs lighter than they = were in 2007. They run cooler. They are simpler to maintain. That comes = from a passion for continuous improvement.=0A =0AAnd those systems are goin= g to become still more efficient and versatile when the electronic density = controllers are installed.=0A =0ARegards, George=0A=0A=0A --0-1825597303-1261321180=:68063 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

I certainly= agree with George in his comments in that a well-designed intercooler will= offer significant performance benefits at altitudes like 18,000.  Whe= n I said "marginal benefit" I was referring to benefit in a more global sen= se.  It all depends on how much of the operation is conducted at 18,00= 0 feet.  From my experience I would guess it would be very, very rare = for someone to spend 50% of of the total hours at or near 18,000.  A 4-hour fligh= t will spend maybe 30 minutes in climb and 3 minutes in descent from 18,000= for 50% spent at 18,000.  A serious cross-country flier might be ther= e for, what, 20%?  And then how much of that time is spent at 30 inche= s manifold pressure, burning close to 30 GPH?  At lower manifold press= ures the higher inlet temperatures are not as detrimental as they are at fu= ll power, where they limit the power output.  In other words, 25 inche= s with a 150F inlet might be equivalent in power - and nearly equivalent in= efficiency - to 24 inches at 100F inlet.  Another thing to be aware o= f - the inlet air temperature does not exactly match the temperature of the= inlet charge as it is trapped in the cylinder, which is, after all, what c= ounts.  Tests I have seen show that the charge is heated about halfway= to the cylinder temperature.  If the cylinder temp is 300F and the incoming charge is 100 the resulting charge temperature is about 200. =  Increase the inlet temp from 100 to 200 and the trapped charge will &= nbsp;be at 250, only 50 higher.  While no one is truly an average oper= ator, my point was that chasing the optimum performance at 18,000 feet may = not be worth the cost and development expense.  Depends on your goals.=  All flights involve operation below 10,000 feet while a limited numb= er involve operation above 18,000.  When flying my TR182 on a lot of c= ross-countries I flew between 12 and 15 a lot, but flew above 18,000 only a= couple of times in 5 years.  Like in the drug commercials, these comm= ents are directed only at turbonormalized nonpressurized oxygen-equipped ai= rcraft operated in non-commercial environments.  Oh, yeah - and by "av= erage" resource-limited owners :-)


Intercoolers ha= ve large benefits  - - - even at sea level."  In this case the tu= rbo is producing negligible pressure, so the temperature rise is dependent = only on the heat picked up going through the turbo and the small compressio= n heating when the turbo has to overcome its own flow restriction.  Th= is is also true when cruising at less than 10,000 feet at reduced manifold = pressure.  Is the added weight, cost and aerodynamic drag more of a de= triment than the cooling is a benefit?

Gary 


>>Here'= s another thought:  A lot of it might depend on your intended usage. &= nbsp;If you want to go really high (over 20K) and have maximum performance = you might want to consider getting the extra power of the TSIO-550.  But if you, lik= e me, might limit altitudes to less than 20K and are more cost and fuel eco= nomy sensitive, then a lower tech solution might be in order.  I flew = for many years behind a Lycoming O-540 that was turbonormalized (C-TR-182) = and it worked quite well.  It didn't have an intercooler or automatic = waste gate - the waste gate was connected to the throttle linkage so there = were no extra levers.  It was fed by a pressurized carburetor, so that= doesn't apply with a Continental.  So the question is, what's wrong w= ith using a standard IO-550 with a turbo and manual waste gate?  The L= ycomings don't bother with a sniffle valve, so there isn't any difference b= etween turbo, fuel injected, or naturally aspirated engines in that regard.=  At 18,000 feet the use of an aftercooler has real, but marginal bene= fit, as the extra aerodynamic drag and pressure loss negate most of the charge-cooling benefit.  Just a thought, suggesting a KISS method= ology.

Gary<<

 

Gary, 

 

So= me comments.

 

I think  new designed high compression engin= es with compressors of any kind should use our present state of knowledge a= nd  incorporate intercoolers - - good intercoolers.

 

 

Intercoolers have large benefits&nbs= p; - - - even at sea level.    I do not think it is accurate to cl= aim that intercoolers only have  =E2=80=9Cmarginal benefit=E2=80=9D be= low 18,000 feet.

 

Here is why I think they are imp= ortant:   At 18,000 feet,  the compressor discharge temperat= ure on a warm day can easily exceed 200dF.    Without an int= ercooler,  200dF  air goes straight to your cylinders.

=

 

With the  TN IO-550,  the  induction air tempe= rature at  30=E2=80=9D at 18,000 feet on a hot day will be less than 1= 05dF.   Typically 95 to 100.   There is a large differe= nce in performance and detonation margins between 200+dF air and < 105dF= air.   

 

The O-540 =E2=80=9Csolution=E2=80=9D= does not really provide more fuel economy.     Rather,= likely just the opposite.

&= nbsp;

The TN IO-550N engine that Tornado Alle= y delivers to Cirrus will   produce   horsepower at 0.3= 8 to 0.39 BHp/lb-fuel/hr  across an altitude and power range that span= s anywhere from sea level to 29000 feet and do so at 200 Hp or at 310 Hp, o= r anywhere in between.   [The real world numbers for the Thielert= diesel was about 0.36 to 0.37 BHP/lb-fuel/hr.] There is no other general a= viation engine installed in any fleet of aircraft that  works anywhere= near that well across that broad range of operating  requirements and= environment.

 

90% of the hours f= lown with those engines are flown between 11,000 and 18,000 feet. &nbs= p;

 

There is a reason why Cirrus has sold ~ 900+&n= bsp; turbonormalized SR22 aircraft in the last 35 months, including 15 months o= f some of the worst times in general aviation history.

 

The reason is - -  the systems consistently exceed the expect= ations of the owners.

 =

During that period of time  T= AT continued to improve and refine those systems.  They are, today,&nb= sp; about 15 lbs lighter than they were in 2007.  They run cooler.&nbs= p; They are simpler to maintain.  That comes from a passion for contin= uous improvement.

 

And those systems are going to= become still more efficient and versatile when the electronic density cont= rollers are installed.

 = ;

Regards,  George

 

=

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