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Gary, et.al, I certainly can’t speak to what others are getting but I have GAMI injectors and my engine has been flow balanced. On consistent 2.5 hour flights from VA to MI I indicate about 8.5 to 8.8 gph. This is backed up by the amount of fuel I replace in the tanks which is about 22 gal. – never been more but sometimes a little less. I fly at 2400 rpm and whatever MP I can get (usually about 21”) at 10,000 ft. So again, for me, the expense of this $995 course just doesn’t work out for my ROI. Danny Miller N 38° 43' 25.7" W 77° 30' 38.6" From: Gary Casey [mailto:casey.gary@yahoo.com]
Sent: Monday, August 22, 2011 10:10 AM
To: lml@lancaironline.net
Subject: Re: How do I run lean of peak? I won't comment on other aspects of LOP operation, as Walter pretty much covered that. But I think the ROI calculations below are not realistic. I flew behind an IO-360(Lyc) for many hours and, depending on the power setting) the ROP fuel flow was more like 11 to 12 GPH. The LOP number was, as Danny suggested, about 8.5. This was at about 12,000 feet and 2500 rpm. Instead of the 0.5 GPH savings, it is more realistically 1.5 and up to 2.5 GPH savings. That brings the break-even in cost down to maybe 100 hours from 331. And that doesn't count the - in my experience - doubled time between spark plug cleanings and potentially longer time between oil changes. I run about 70 hours instead of 50. Then there is the increased engine life because of lower peak cylinder pressures and lower CHT's. Granted, you will take a minute or two longer to get where you are going. My ES cruises at about 174 LOP (12.3 GPH) and 180 ROP (15+ GPH). What's not to like? I’m not convinced of the ROI for spending $995 on this course in my particular case. As an example, for my LNC2 with an IO-360, if I burn 9 gph running ROP and 8.5 gph running LOP (best case scenario), how long does it take to recover the expense? To keep it simple, let’s say I spend $6/gal. So, that’s $995 x gal/$6 / 0.5gph = 331.7 hrs, or about 3 years of flying. So, the question becomes, is it worth all the hub bub? Again, for me, I think not. For you guys with the high burn rates, maybe so. But what is your actual hourly saving and is it worth the additional stress on your engines for the potentially much lower TBO? You decide and your mileage may vary. |
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