X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 25 Mar 2009 08:16:30 -0400 Message-ID: X-Original-Return-Path: Received: from mailrelay.embarq.synacor.com ([208.47.184.3] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3558614 for lml@lancaironline.net; Wed, 25 Mar 2009 06:33:51 -0400 Received-SPF: pass receiver=logan.com; client-ip=208.47.184.3; envelope-from=liegner@embarqmail.com X-Original-Return-Path: X_CMAE_Category: 0,0 Undefined,Undefined X-CNFS-Analysis: v=1.0 c=1 a=1oqGTYSLAAAA:8 a=Ia-xEzejAAAA:8 a=RnOZ9p3EAAAA:8 a=Y4HaiTZi6akhiCfBbpIA:9 a=tloLz64CPr7wJ4i7amoA:7 a=AdsZaMU8Pd3WKNGNL0oJ7ZUnEiAA:4 a=rCILQYlsaxwA:10 a=cvn8laQl214A:10 a=EzXvWhQp4_cA:10 a=xdHejXoO0hc71jjZBkIA:9 a=CM9GIqsYXNwdwU_f9QEA:7 a=ZKlJYcNzmsAi6ci23dHsUElHAuYA:4 a=AfD3MYMu9mQA:10 X-CM-Score: 0 X-Scanned-by: Cloudmark Authority Engine Authentication-Results: smtp02.embarq.synacor.com smtp.user=liegner@embarqmail.com; auth=pass (LOGIN) Received: from [71.1.169.171] ([71.1.169.171:23766] helo=[172.16.1.2]) by mailrelay.embarq.synacor.com (envelope-from ) (ecelerity 2.2.2.36 r(27513/27514)) with ESMTPA id 5D/7F-19093-9680AC94; Wed, 25 Mar 2009 06:33:15 -0400 Mime-Version: 1.0 X-Sender: liegner@embarqmail.com@pop.embarqmail.com X-Original-Message-Id: X-Original-Date: Wed, 25 Mar 2009 06:28:22 -0400 X-Original-To: "Lancair Mailing List" From: "Jeffrey Liegner, MD" Subject: Re: FAA Swft 702 Fuel Test Report Content-Type: multipart/alternative; boundary="============_-974145289==_ma============" --============_-974145289==_ma============ Content-Type: text/plain; charset="iso-8859-1" ; format="flowed" Content-Transfer-Encoding: 8bit From a pilot/engineer friend of mine: Pass this along to the LML recipient list if you'd like. I read through the whole test report and I looked through most of the graphs although I really concentrated on the results of the TIO-540 engine since it is the one that most closely resembles the Continental in our airplanes. It looks like a workable alternative to 100LL with the caveats noted below as far as energy/lb and elevated EGTs. The first thing that struck me is that none of the tests of the Swift 702 fuel got the engine to run LOP. Even at the lowest power test which was 60%. I believe this is because the TIT hit redline (1650*F) as they leaned so they terminated leaning before going LOP. The 100LL at 60% tests went LOP because the TITs were 50 degrees lower and they didn't hit 1650*F before they went LOP. So there is no data so far how this fuel will perform LOP. Specifically how power drops off as you move further LOP. We know that with 100LL power drops off about 10% when one moves from 100*F ROP to 50*F LOP. What will Swift 702 do? Since max TIT is 1750*F on the Continental TSIO-550 engines (with a 1850*F limit for 30secs max) this may allow us to find peak TIT and lean properly to a reasonable LOP. Going too far LOP actually causes an increase in BSFC with fixed timing with 100LL. The other big question is what does CHT do? We know EGTs are higher with Swift 702. Higher EGTs do not necessarily mean that CHTs will be higher also(except in the immeadiate vicinity of the exhaust port). Advancing timing lowers the Swift 702 EGTs close to what they are with 100LL. This is explained as being due to the slower burning of Swift 702. I know from my experience that advancing timing as they did to try to lower EGTs actually increases CHTs. I did not see detailed data on CHTs in the report when they tried this. The detonation margins with Swift 702 were higher so compression ratios could be higher to take advantage of this. If done this would lower EGTs. Increasing compression ratio increases thermodynamic efficiency because it allows the capture and conversion to work of the expanding gases to occur over a wider expansion ratio. That is primarily why the Diesel cycle is more efficient than the Otto cycle and why diesels have lower EGTs than gas engines. The other big question is altitude testing. None was done in these tests and induction air temps go up quite a bit at high altitudes in turbocharged engines, so this is another important question to answer. ----- Original Message ----- From: Jeffrey Liegner, MD To: Recipient List Suppressed: Sent: Monday, March 23, 2009 9:28 PM Subject: Fwd: FAA Swft 702 Fuel Test Report >To: lml@lancaironline.net >Date: Mon, 23 Mar 2009 12:59:09 -0400 > From: "Colyn Case at earthlink" Subject: Re: [LML] FAA Swft 702 Fuel test report It's worth reading the summary section on page 29. It's only 2 pages Highlights: - swift fuel weighs 21% more but only increases range by 8% - if you are weight limited for fuel you will only get 89% as much range. - if you are gallon limited for fuel you will get 8% more range - egt's increase by 50 dF. On my installation that would mean having to back off the mixture an additional 50dF to keep the TIT's in range - something about aromatics I didn't understand Overall: It's better than not flying but not as far or as fast as 100LL. --------------------------------------------- ----- Original Message ----- From: To: lml@lancaironline.net Sent: Sunday, March 22, 2009 4:13 PM Subject: [LML] FAA Swft 702 Fuel test report I found a link to a pdf of the Swift fuel test report from FAA testing done last year. Looks like there is a heat issue ( around 50F greater than 100LL) and peak HP is about 1.3% less than 100LL. I know very little about the chemistry behind fuels and engine design, but if more heat is generated, how come that can’t be harnessed and turned into power? http://www.tc.faa.gov/its/worldpac/techrpt/ar0853.pdf Kevin --============_-974145289==_ma============ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Re: FAA Swft 702 Fuel Test Report
From a pilot/engineer friend of mine:
 
Pass this along to the LML recipient list if you'd like. I read through the whole test report and I looked through most of the graphs although I really concentrated on the results of the TIO-540 engine since it is the one that most closely resembles the Continental in our airplanes. It looks like a workable alternative to 100LL with the caveats noted below as far as energy/lb and elevated EGTs. 

The first thing that struck me is that none of the tests of the Swift 702 fuel got the engine to run LOP. Even at the lowest power test which was 60%.  I believe this is because the TIT hit redline (1650*F) as they leaned so they terminated leaning before going LOP. The 100LL at 60% tests went LOP because the TITs were 50 degrees lower and they didn't hit 1650*F before they went LOP. So there is no data so far how this fuel will perform LOP. Specifically how power drops off as you move further LOP. We know that with 100LL power drops off about 10% when one moves from 100*F ROP to 50*F LOP. What will Swift 702 do? Since max TIT is 1750*F on the Continental TSIO-550 engines (with a 1850*F limit for 30secs max) this may allow us to find peak TIT and lean properly to a reasonable LOP. Going too far LOP actually causes an increase in BSFC with fixed timing with 100LL.
 
The other big question is what does CHT do? We know EGTs are higher with Swift 702. Higher EGTs do not necessarily mean that CHTs will be higher also(except in the immeadiate vicinity of the exhaust port). Advancing timing lowers the Swift 702 EGTs close to what they are with 100LL. This is explained as being due to the slower burning of Swift 702. I know from my experience that advancing timing as they did to try to lower EGTs actually increases CHTs. I did not see detailed data on CHTs in the report when they tried this.
 
The detonation margins with Swift 702 were higher so compression ratios could be higher to take advantage of this. If done this would lower EGTs. Increasing compression ratio increases thermodynamic efficiency because it allows the capture and conversion to work of the expanding gases to occur over a wider expansion ratio. That is primarily why the Diesel cycle is more efficient than the Otto cycle and why diesels have lower EGTs than gas engines.
 
The other big question is altitude testing. None was done in these tests and induction air temps go up quite a bit at high altitudes in turbocharged engines, so this is another important question to answer.
 

----- Original Message -----
From: Jeffrey Liegner, MD
To: Recipient List Suppressed:
Sent: Monday, March 23, 2009 9:28 PM
Subject: Fwd: FAA Swft 702 Fuel Test Report

To:  lml@lancaironline.net
Date: Mon, 23 Mar 2009 12:59:09 -0400
From: "Colyn Case at earthlink"
Subject: Re: [LML] FAA Swft 702 Fuel test report
It's worth reading the summary section on page 29.  It's only 2 pages
 
Highlights:
- swift fuel weighs 21% more but only increases range by 8%
- if you are weight limited for fuel you will only get 89% as much range.
- if you are gallon limited for fuel you will get 8% more range
- egt's increase by 50 dF.  On my installation that would mean having to back off the mixture an additional 50dF to keep the TIT's in range
- something about aromatics I didn't understand
 
Overall:
It's better than not flying but not as far or as fast as 100LL.
 
---------------------------------------------
----- Original Message -----
From:
To: lml@lancaironline.net
Sent: Sunday, March 22, 2009 4:13 PM
Subject: [LML] FAA Swft 702 Fuel test report

I found a link to a pdf of the Swift fuel test report from FAA testing done last year.  Looks like there is a heat issue ( around 50F greater than 100LL) and peak HP is about 1.3% less than 100LL.

 
I know very little about the chemistry behind fuels and engine design, but if more heat is generated, how come that can’t be harnessed and turned into power?

 
http://www.tc.faa.gov/its/worldpac/techrpt/ar0853.pdf
 
Kevin
 
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