X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 01 Aug 2005 20:54:56 -0400 Message-ID: X-Original-Return-Path: Received: from wind.imbris.com ([216.18.130.7] verified) by logan.com (CommuniGate Pro SMTP 4.3.6) with ESMTPS id 621507 for lml@lancaironline.net; Mon, 01 Aug 2005 15:56:40 -0400 Received-SPF: none receiver=logan.com; client-ip=216.18.130.7; envelope-from=brent@regandesigns.com Received: from [192.168.1.100] (wireless-216-18-135-19.imbris.com [216.18.135.19]) (authenticated bits=0) by wind.imbris.com (8.12.11/8.12.11.S) with ESMTP id j71JtG9S088112 for ; Mon, 1 Aug 2005 12:55:44 -0700 (PDT) (envelope-from brent@regandesigns.com) X-Original-Message-ID: <42EE7E1E.4030706@regandesigns.com> X-Original-Date: Mon, 01 Aug 2005 12:55:10 -0700 From: Brent Regan User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: Lancair Subject: RE: Turbine Revolution Content-Type: multipart/alternative; boundary="------------060302020608080101000607" This is a multi-part message in MIME format. --------------060302020608080101000607 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit I was able to spend some time at the Innodyne tent and examining the twin engine unit on display in the Lancair tent. There was also a high wing on the flight line with the engine installed and (apparently) flying. From what I could see from the outside, it seems like an attractive alternative, if you have money to burn. The engine has a single stage centrifugal turbine and compressor. Imagine a big turbocharger (apologies to Innodyne engineers). On interrogation, the Innodyne representative claimed an overall compression ration of 4.5 to 1 and a fuel burn of 8 gallons per hour per one hundred horsepower. Later in the conversation he mentioned that the horsepower was rated at sea level but the fuel burn was from a 9,000' MSL test flight so the fuel burn claim is significantly underestimated. If you calculate the horsepower derating based on the density delta from 0 to 9,000' MSL you will have 76 horsepower where you once had 100 so you now have 8 gallons per hour per 76 horsepower or (given 8 lbs per gallon for Jet-A) 64 lbs per hour per 76 horsepower or 0.84 pounds per horsepower hour. My Lycoming running at 75% power and 150 deg F rich of peak burns 0.47 pounds per horsepower hour. To be fair, there are 15% more pounds in a gallon of Jet-A than a gallon of 100LL and Jet-A is ~10% cheaper so the fuel consumption of the Innodyne only 116% of the Lycoming comparing dollars per hour. All this assumes that the horsepower number was not overstated and the fuel consumption was not understated, in the best OSH tradition. Of course my calculations are very rough estimates. For a sanity check we can review the performance of a similar engine made by Solar, the T62, you will find the overall compression ration listed as 3.5 with a BSFC of 1.3 Lb/HpHr. Is it reasonable to expect a 35% reduction in fuel consumption? The laws of thermodynamics are very difficult to break. Turbine (and IC) engines benefit from size such that bigger is more efficient. A twin pack of smaller, less efficient engines, will not be as efficient as a single larger engine. I am encouraged by the advent of engine alternatives. I am also hopeful that accurate data will be forthcoming so that a reasoned performance comparison can be performed. Show me the data......Until then "Caveat Emptor". Regards Brent Regan --------------060302020608080101000607 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit I was able to spend some time at the Innodyne tent and examining the twin engine unit on display in the Lancair tent. There was also a high wing on the flight line with the engine installed and (apparently) flying. From what I could see from the outside, it seems like an attractive alternative, if you have money to burn.

The  engine has a single stage centrifugal turbine and compressor. Imagine a big turbocharger (apologies to Innodyne engineers).  On interrogation, the Innodyne representative claimed an overall compression ration of 4.5 to 1 and a fuel burn of 8 gallons per hour per one hundred horsepower.  Later in the conversation he mentioned that the horsepower was rated at sea level but the fuel burn was from a 9,000' MSL test flight so the fuel burn claim is significantly underestimated.  If you calculate the horsepower derating based on the density delta from 0 to 9,000' MSL you will have 76 horsepower where you once had 100 so you now have 8 gallons per hour per 76 horsepower or (given 8 lbs per gallon for Jet-A) 64 lbs per hour per 76 horsepower or  0.84 pounds per horsepower hour.  My Lycoming running at 75% power and 150 deg F rich of peak burns 0.47 pounds per horsepower hour. To be fair, there are 15% more pounds in a gallon of Jet-A than a gallon of 100LL and Jet-A is ~10% cheaper so the fuel consumption of the Innodyne only 116% of the Lycoming comparing dollars per hour. All this assumes that the horsepower number was not overstated and the fuel consumption was not understated, in the best OSH tradition. Of course my calculations are very rough estimates.

For a sanity check we can review the performance of a similar engine made by Solar, the T62,  you will find the overall compression ration listed as 3.5 with a  BSFC of 1.3 Lb/HpHr.  Is it reasonable to expect a 35% reduction in fuel consumption?  The laws of thermodynamics are very difficult to break.

Turbine (and IC) engines benefit from size such that bigger is more efficient. A twin pack of smaller, less efficient engines, will not be as efficient as a single larger engine.

I am encouraged by the advent of engine alternatives. I am also hopeful that accurate data will be forthcoming so that a reasoned performance comparison can be performed.

Show me the data......Until then "Caveat Emptor".

Regards
Brent Regan


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