X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 13 Sep 2005 21:35:52 -0400 Message-ID: X-Original-Return-Path: <210flyer@earthlink.net> Received: from smtpauth05.mail.atl.earthlink.net ([209.86.89.65] verified) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 720783 for lml@lancaironline.net; Tue, 13 Sep 2005 16:39:04 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.65; envelope-from=210flyer@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=SDlEwTJSrf2hrec+UmdwLgcZPHmu/TQckJcurywD9u7g+ojwn/GQH0FLAsrxw4kV; h=Received:From:To:Subject:Date:MIME-Version:Content-Type:X-Mailer:thread-index:X-MimeOLE:Message-ID:X-ELNK-Trace:X-Originating-IP; Received: from [68.166.211.175] (helo=dune) by smtpauth05.mail.atl.earthlink.net with asmtp (Exim 4.34) id 1EFHXn-00051K-ON for lml@lancaironline.net; Tue, 13 Sep 2005 16:38:20 -0400 From: "Mike Hutchins" <210flyer@earthlink.net> X-Original-To: "Lancair Mailing List" Subject: Turbo Diesel vs. Turbo Gas (JET A vs. 100LL) X-Original-Date: Tue, 13 Sep 2005 14:37:52 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_01D2_01C5B870.B953EC20" X-Mailer: Microsoft Office Outlook, Build 11.0.6353 thread-index: AcW4owNo1CIR0t/BSc64rpGPL3uQFA== X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2670 X-Original-Message-ID: X-ELNK-Trace: 96606e18df264d301aa676d7e74259b7b3291a7d08dfec79dba62ad1bfa88e347975845769e82dd3350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 68.166.211.175 This is a multi-part message in MIME format. ------=_NextPart_000_01D2_01C5B870.B953EC20 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi Gang, With the recent discussion about the Innodyne turbine and diesel aircraft engines in general there has been some misinformation about the inherent advantage of Jet A over 100LL with regards to energy content. Here is an excellent link to a Chevron web site that covers everything you might want to know about various aviation fuels. In particular, the energy density of jet fuel, on a BTU/Gal basis does show about an 11.8% advantage over Avgas. On the other hand, if you look at the energy density on a BTU/Lb basis, Avgas has the advantage by about 1%. So where does the supposed 30% energy advantage of diesel engines over Avgas engines come from? Do diesel engines really enjoy a 30% efficiency advantage over aircraft engines? In terms of BSFC, they are starting from a 1% disadvantage solely on the basis of the energy content per pound of fuel. Granted, diesel engines operate at a much higher compression ratio (the Thielert Centurion 4.0L engine is 18.5:1) than our Avgas engines, but is that difference sufficient to extract more than 30% efficiency. I don't think so. Thielert claims a 0.36 BSFC for their 1.7L turbocharged diesel engine with a compression ratio of 18:1. The GAMI folks report that our turbocharged Avgas engines typically achieve a BSFC in the range of 0.41-0.43 when operated LOP. This works out to a 16% efficiency advantage per pound of fuel for the turbo-diesel engine. Taking it a step further, when we fuel up our diesel powered airplane, our fuel tanks will hold the same number of gallons of fuel whether it is Jet A or 100LL, but the Jet A will weigh 17% more than a load of 100LL. Ahh, this is how we get the 30% advantage over our 10LL engines. When we combine the 16% greater load of BTUs per wing with the 16% better efficiency of a turbo-diesel engine, we do, in fact end up with an aircraft that has a 30% greater potential energy conversion than our current rides. Now the question is, can we really go 30% farther between fill ups? Wow, that 350HP, 4.0L certificated (in Europe) turbo-diesel engine is starting to sound pretty good. Too bad it weighs 600 pounds, although Thielert claims the installed weight is comparable to a TCM engine. Time will tell. Best Regards, Mike http://www.chevron.com/products/prodserv/fuels/bulletin/aviationfuel/2_at_fu el_perf.shtm http://www.centurion-engines.com/c40/c40_data.htm ------=_NextPart_000_01D2_01C5B870.B953EC20 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi Gang,

 

With the recent discussion about the Innodyne turbine = and diesel aircraft engines in general there has been some misinformation = about the inherent advantage of Jet A over 100LL with regards to energy content. = Here is an excellent link to a Chevron web site that covers everything you might want to know about various aviation fuels. In particular, the energy density of jet fuel, on a = BTU/Gal basis does show about an 11.8% advantage over Avgas. On the other hand, = if you look at the energy density on a BTU/Lb basis, Avgas has the advantage by = about 1%.

 

So where does the supposed 30% energy advantage of = diesel engines over Avgas engines come from? Do diesel engines really enjoy a 30% = efficiency advantage over aircraft engines? In terms of BSFC, they are starting = from a 1% disadvantage solely on the basis of the energy content per pound of = fuel. Granted, diesel engines operate at a much higher compression ratio (the Thielert Centurion 4.0L engine is 18.5:1) than our Avgas engines, but is = that difference sufficient to extract more than 30% efficiency. I don’t = think so.

 

Thielert claims a 0.36 BSFC for their 1.7L = turbocharged diesel engine with a compression ratio of 18:1. The GAMI folks report = that our turbocharged Avgas engines typically achieve a BSFC in the range of 0.41-0.43 when = operated LOP. This works out to a 16% efficiency advantage per pound of fuel for = the turbo-diesel engine.

 

Taking it a step further, when we fuel up our diesel = powered airplane, our fuel tanks will hold the same number of gallons of fuel = whether it is Jet A or 100LL, but the Jet A will weigh 17% more than a load of = 100LL. Ahh, this is how we get the 30% advantage over our 10LL engines. When we combine the 16% greater load of BTUs per wing with the 16% better = efficiency of a turbo-diesel engine, we do, in fact end up with an aircraft that has a = 30% greater potential energy conversion than our current rides. Now the = question is, can we really go 30% farther between fill = ups?

 

Wow, that 350HP, 4.0L certificated (in Europe) turbo-diesel engine is starting to sound pretty good. Too bad it weighs = 600 pounds, although Thielert claims the installed weight is comparable to a = TCM engine. Time will tell…

 

 

Best Regards,

Mike

 

 

 

 

http://www.chevron.com/products/prodserv/fuels/b= ulletin/aviationfuel/2_at_fuel_perf.shtm

=

 

http://www.centurion-engines.com/c40/c40_data.htm=

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